101
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Affiliation(s)
- D Epstein
- Department of Ophthalmology, University of Zurich, Switzerland
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102
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Lee JB, Seong GJ, Lee JH, Seo KY, Lee YG, Kim EK. Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia. J Cataract Refract Surg 2001; 27:565-70. [PMID: 11311625 DOI: 10.1016/s0886-3350(00)00880-4] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To compare the effectiveness, safety, and stability of laser epithelial keratomileusis (LASEK), a modified photorefractive keratectomy (PRK) technique, with those of conventional PRK for low to moderate myopia. SETTING Department of Ophthalmology, Yonsei University School of Medicine, Seoul, Korea. METHODS In this prospective study, 27 patients with a manifest refraction of -3.00 to -6.50 diopters were treated and followed for 3 months. In each case, PRK was performed in 1 eye and LASEK in the other eye. The first eye treated and the surgical method used in the first eye were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity (UCVA), manifest refraction, corneal haze, and surgical preference were examined in PRK- and LASEK-treated eyes. RESULTS During the 3 month follow-up, there were no significant between-eye differences in epithelial healing time, UCVA, or refractive error. However, LASEK-treated eyes had lower postoperative pain scores (P =.047) and corneal haze scores (1 month; P =.02) than PRK-treated eyes. Seventeen patients (63%) preferred the LASEK procedure. CONCLUSIONS Laser epithelial keratomileusis safely and effectively treated eyes with low to moderate myopia. It reduced the incidence of significant postoperative pain and corneal haze and may prevent the flap- and interface-related problems of laser in situ keratomileusis.
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Affiliation(s)
- J B Lee
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
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103
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Weber BA, Gan L, Fagerholm PP. Short-term impact of corticosteroids on hyaluronan and epithelial hyperplasia in the rabbit cornea after photorefractive keratectomy. Cornea 2001; 20:321-4. [PMID: 11322424 DOI: 10.1097/00003226-200104000-00016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the impact of corticosteroids on subepithelial hyaluronan deposition and corneal epithelium thickness in the first 10 days after photorefractive keratectomy (PRK) and to analyze a possible contralateral effect of corticosteroids. METHODS Thirty-two New Zealand white rabbits were assigned into two groups and had a transepithelial 5.0-mm diameter, 8.00-diopter myopic PRK performed on one eye. The corticosteroid treatment group (16 animals) received 0.1 mL of methylprednisolone 4% subconjunctivally on the operation table, followed by 0.1% dexamethasone eye drops six times a day during the postoperative period. The sodium chloride (NaCl) treatment group received topical isotonic NaCl eye drops six times a day. In each treatment group, eight animals were killed after 3 and 9 days, respectively. The harvested specimens were stained for hyaluronan and the epithelial thickness was measured. RESULTS In contrast to the epithelial thickness, the subepithelial hyaluronan did not show a significant increase during the observation period. The corticosteroid treated group showed at both time-points significantly less subepithelial hyaluronan formation as well as a significantly thinner epithelium, when compared with the NaCl-treated group. At 9 days, the corticosteroid-treated group showed a mild epithelial hyperplasia in only one of eight eyes, whereas this was a common finding in the NaCl-treated group. We detected no hyaluronan deposits in any contralateral-untreated eye, and the epithelial thickness did not differ significantly between any of the four contralateral-untreated eye groups. CONCLUSIONS Corticosteroid medication during the first 10 days after operation reduces the amount of subepithelial hyaluronan production and inhibits the epithelial proliferation, and epithelial hyperplasia is prevented. Neither a contralateral hyaluronan deposition nor a contralateral corticosteroid effect could be detected.
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Affiliation(s)
- B A Weber
- St Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
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Newsom RS, McAlister JC, Saeed M, McHugh JD. Transpupillary thermotherapy (TTT) for the treatment of choroidal neovascularisation. Br J Ophthalmol 2001; 85:173-8. [PMID: 11159481 PMCID: PMC1723824 DOI: 10.1136/bjo.85.2.173] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To assess the effectiveness of transpupillary thermotherapy (TTT) for the treatment of classic and occult choroidal neovascularisation (CNV). METHOD In a retrospective, case selected, open label trial 44 eyes of 42 patients with CNV secondary to age related macular degeneration (ARMD) were studied. 44 eyes with angiographically defined CNV were treated with diode laser (810 nm) TTT. Laser beam sizes ranged between 0.8 and 3.0 mm and power settings between 250-750 mW. Treatment was given in one area for 1 minute, the end point being no visible change, or a slight greying of the retina. Outcome was assessed with Snellen visual acuity and clinical examination; in 24/44 patients angiographic follow up was available. RESULTS 12 predominantly classic CNV and 32 predominantly occult membranes were followed up for a mean of 6.1 months (range 2-19). Mean change in vision for classic membranes was -0.75 (SD 1.75) Snellen lines and occult membranes was -0.66 Snellen lines (2.1) (p>0.05). Predominantly classic membranes were closed in 75% (95% CI: 62.5-87.5) of eyes, remained persistent in 25% (95% CI: 12.5-37.5); no recurrences occurred. Predominantly occult membranes were closed in 78% (95% CI: 70.1-85.3) of eyes, remained persistent in 12.5% (95% CI: 6.6-18.5), and were recurrent in 5.1% (95% CI: 4.2-14.3). CONCLUSIONS Transpupillary thermotherapy is a potential treatment for CNV. It is able to close choroidal neovascularisation while maintaining visual function in patients with classic and occult disease. Further trials of TTT are needed to compare this intervention with the natural history and other treatment modalities.
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Affiliation(s)
- R S Newsom
- King's College Hospital, Denmark Hill, London SE5 9RS, UK.
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105
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Lee YG, Chen WY, Petroll WM, Cavanagh HD, Jester JV. Corneal haze after photorefractive keratectomy using different epithelial removal techniques: mechanical debridement versus laser scrape. Ophthalmology 2001; 108:112-20. [PMID: 11150274 DOI: 10.1016/s0161-6420(00)00426-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To determine differences of corneal wound healing and haze after photorefractive keratectomy (PRK) using either mechanical epithelial debridement or laser-scrape epithelial removal in human subjects. DESIGN A 6-month randomized, masked, prospective, paired-eye clinical study. PARTICIPANTS Twenty eyes in 10 myopic patients treated between March 1999 and May 1999. INTERVENTION Photorefractive keratectomy treatments with two different epithelial removal techniques. Continuous z-scan of confocal image, termed confocal microscopy through focusing (CMTF), was performed before surgery and at 3 weeks, 6 weeks, 3 months, and 6 months after surgery. MAIN OUTCOMES MEASURES Epithelial and stromal thickness measurement, achieved stromal ablation depth, and objective assessment of corneal light-backscattering (corneal haze) were obtained from digital image analysis of the CMTF scans. Manifest refraction was also measured. Student's paired t test or two-way repeated-measures analysis of variance after rank transformation were performed to evaluate statistical differences between groups. RESULTS Comparison of the mean posttreatment spherical equivalent between the two techniques showed no statistically significant difference. In preoperative corneas, mean epithelial thickness was 50.08+/-3.70 microm in the mechanical debridement group and 50.49+/-4.01 microm in laser-scrape group (not significant). For both groups, the epithelium was significantly thinner at 3 weeks, but returned to preoperative values by 6 months, with no difference between groups. Planned stromal ablation depth by PRK was 59.38+/-11.48 microm (39-73 microm; n = 8) in the mechanical group and 57.75 +/- 7.21 microm (48-70 microm; n = 8) in the laser-scrape group. Achieved stromal ablation depth was not significantly different between the two groups. Most importantly, in both groups CMTF-measured corneal haze increased significantly after surgery, peaked at 3 months, and then decreased at 6 months, with no significant difference between groups. (Power = 0.96). CONCLUSIONS There is no significant difference in the corneal wound healing response between mechanical epithelial debridement versus laser-scrape technique in human myopic eyes undergoing PRK.
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Affiliation(s)
- Y G Lee
- Department of Ophthalmology, University of Texas, Southwestern Medical Center at Dallas, Dallas, Texas, USA
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106
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Reviglio VE, Bossana EL, Luna JD, Muiño JC, Juarez CP. Laser in Situ Keratomileusis for Myopia and Hyperopia Using the Lasersight 200 Laser in 300 Consecutive Eyes. J Refract Surg 2000; 16:716-23. [PMID: 11110312 DOI: 10.3928/1081-597x-20001101-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate effectiveness, safety, predictability, and short-term stability of laser in situ keratomileusis (LASIK) using the LaserSight Compac-200 Mini excimer laser with software version 9.0, for all refractive errors. METHODS One hundred fifty consecutive patients (300 eyes) that received bilateral LASIK for myopia, hyperopia, and astigmatism were studied prospectively. A new 9.0 software version applying a modified nomogram that takes advantage of bilateral surgery was used. Follow-up at 6 months was available for 267 eyes (89%). RESULTS Six months postoperatively, 131 eyes (96.32%) in the low to moderate myopia group (-1.00 to -5.99 D; n=136) had a spherical equivalent refraction within +/-1.00 D, and 123 eyes (90.44%) were within +/-0.50 D of emmetropia. In the high to extreme myopia group (-6.00 to -25.00 D; n=114), 97 eyes (87.08%) had a spherical equivalent refraction within +/-1.00 D and 78 eyes (68.42%) were within +/-0.50 D of emmetropia. In the hyperopia group (+1.00 to +6.00 D; n=50), 44 eyes (88%) had a postoperative spherical equivalent refraction within +/-1.00 D, and 31 eyes (62%) were within +/-0.50 D of emmetropia. Mean change in spherical equivalent refraction at 6 months was less than -0.50 D in the low to high myopia groups and -1.16 +/- 0.55 D in the extreme myopia group. At 6 months follow-up, uncorrected visual acuity was 20/20 or better in 73 eyes (54%) in the low to moderate myopia groups and 21 eyes (18%) in the high to extreme myopia groups. In the hyperopia group at 6 months follow-up, uncorrected visual acuity was 20/20 or better in 31 eyes (62%) and 20/40 or better in 41 eyes (82%). Only two eyes had a temporary loss of two or more lines of spectacle-corrected visual acuity due to corneal folds that were surgically treated. Six months after LASIK, no eye had lost any lines of best spectacle-corrected visual acuity in this series. CONCLUSIONS Our modified LASIK nomogram with the 9.0 software of the LaserSight 200 excimer laser (with a larger and smoother ablation pattern) resulted in safe and effective outcomes for the treatment of low to high myopia, astigmatism, and hyperopia.
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107
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Keskinbora HK. Long-term results of multizone photorefractive keratectomy for myopia of -6.0 to -10.0 diopters. J Cataract Refract Surg 2000; 26:1484-91. [PMID: 11033395 DOI: 10.1016/s0886-3350(00)00563-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the 4 year refractive outcome of multizone photorefractive keratectomy (PRK) in eyes with high myopia. SETTING ++SSK Okmeydani Education Hospital, Eye Clinic, Türkiye Hospital, Okmeydani, Istanbul. METHODS Three ablation zones were used in 92 eyes of 48 patients whose refractive errors were between -6.0 and -10.0 diopters (D) (mean spherical equivalent -7.42 D +/- 1.25 [SD]). The zones were between 4.5 and 6.0 mm based on the thickness of the cornea and the refractive correction. After the epithelium healed, dexamethasone was applied 4 times a day during the first postoperative week and then fluorometholone was applied 4 times a day for a minimum of 4 weeks. If hyperopia was found post-PRK, the steroid dose was gradually tapered. The patients were examined 1 and 3 days postoperatively, 1, 2, and 4 weeks, every 3 months for the first year, and then every 6 months. RESULTS All patients were overcorrected in the first postoperative week. At 2 and 3 weeks, the mean manifest refraction was closer to emmetropia. At 6 months, the refraction was stable. The mean spherical equivalent was -0.10 D at the end of the first year, and stabilization continued for 4 years. After the third month, the haze regressed gradually without requiring treatment. In 1 patient, herpes simplex keratitis developed and healed in a short time with topical antiviral therapy. Nineteen eyes regressed more than -1.0 D, 4 eyes were overcorrected, 4 eyes had central islands (at 6 months), and 2 eyes were undercorrected. Two eyes were retreated for regression; 1 eye was retreated for undercorrection and 1 eye, for central island. An uncorrected visual acuity of 20/40 or better was achieved in 79.2% of eyes, and 73.9% were within +/-1. 0 D of the intended correction. CONCLUSION ++Photorefractive keratectomy was effective in treating high myopia between -6.0 and -10.0 D. The induced refractive changes stabilized between 6 and 9 months. In most patients, no significant regression was found after this period.
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Affiliation(s)
- H K Keskinbora
- SSK Okmeydani Education Hospital, Eye Clinic, Istanbul Türkiye Hospital, Okmeydani, Istanbul, Turkey.
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108
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Vetrugno M, Maino A, Cardia L. Prospective Randomized Comparison of Simultaneous and Sequential Bilateral Photorefractive Keratectomy for the Correction of Myopia. Ophthalmic Surg Lasers Imaging Retina 2000. [DOI: 10.3928/1542-8877-20000901-08] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lee JB, Ryu CH, Kim J, Kim EK, Kim HB. Comparison of tear secretion and tear film instability after photorefractive keratectomy and laser in situ keratomileusis. J Cataract Refract Surg 2000; 26:1326-31. [PMID: 11020617 DOI: 10.1016/s0886-3350(00)00566-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate and compare tear secretion and tear film instability following photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). SETTING Department of Ophthalmology, Yonsei University School of Medicine, Seoul, Korea. METHODS In a prospective study, 36 eyes (21 patients) had PRK and 39 eyes (25 patients) had LASIK to correct myopia. Tear secretion and tear film instability were tested preoperatively and 3 and 6 months postoperatively using Schirmer test values, tear breakup time (BUT) scores, and tear osmolarity. RESULTS Six months after surgery, the change in Schirmer test values from preoperative levels was -14.57% +/- 6.39% (SD) in the PRK eyes and -23.40% +/- 5.94% in the LASIK eyes and the change in BUT scores, -12.54% +/- 8.28% and -18.79% +/- 13.01%, respectively. The change in tear osmolarity was 14.95% +/- 6.46% and 35.63% +/- 8.51%, respectively. CONCLUSIONS The decrease in tear secretion was greater after LASIK than after PRK at 6 months. Proper treatment of dry eye is required after LASIK and PRK, particularly in the LASIK postoperative period.
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Affiliation(s)
- J B Lee
- Institute of Vision Research, Department of Ophthalmology, Seoul, South Korea.
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Abstract
PURPOSE To review the major advances in the field of refractive surgery occurring over the past 25 years. METHODS Literature review. RESULTS The major developments in refractive surgery over the past 25 years are reviewed. CONCLUSIONS The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.
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Affiliation(s)
- R D Stulting
- Cornea Service, Emory University School of Medicine, Department of Ophthalmology, Atlanta, Georgia, USA
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111
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Moller-Pedersen T, Cavanagh HD, Petroll WM, Jester JV. Stromal wound healing explains refractive instability and haze development after photorefractive keratectomy: a 1-year confocal microscopic study. Ophthalmology 2000; 107:1235-45. [PMID: 10889092 DOI: 10.1016/s0161-6420(00)00142-1] [Citation(s) in RCA: 208] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To evaluate the mechanism(s) producing refractive instability and corneal haze development after photorefractive keratectomy (PRK). DESIGN Prospective, nonrandomized, comparative case series, self-controlled. PARTICIPANTS Seventeen eyes of 17 patients with low- to moderate-grade myopia (-2.88 to -9.13 diopters [D]) were included. METHODS Surgical intervention was a standardized, 6-mm diameter PRK procedure using the Meditec MEL 60 excimer laser (Aesculap-Meditec, Heroldsberg, Germany). The photoablation center was evaluated before surgery and at 1, 3, 6, 9, and 12 months after PRK using rapid, continuous z-scans of confocal images, termed confocal microscopy through focusing (CMTF). MAIN OUTCOME MEASURES Simultaneous epithelial and stromal thickness analysis and objective assessment of corneal light backscattering were obtained from digital image analysis of the CMTF scans. Corneal reinnervation and anterior stromal keratocyte density and wound healing morphologic features were evaluated on high resolution, in vivo confocal images. Manifest refraction was measured and corneal clarity was graded by slit-lamp biomicroscopy. RESULTS Epithelial thickness averaged 45+/-10 microm at 1 month, 50+/-8 microm at 3 months, and 52+/-6 microm at 12 months after PRK, as compared with 51+/-4 microm before surgery, demonstrating complete restoration of the preoperative thickness without compensatory hyperplasia. Interestingly, epithelial rethickening had no significant correlation with refractive regression. By contrast, stromal regrowth (from 1-12 months) averaged 6+/-12 microm (range, 27 microm thinning-22 microm rethickening) and correlated closely (r = 0.84, P<0.001) with changes in refraction that averaged 0.84+/-1.23 D, ranging from -1.63 D (hyperopic shift) to +3.38 D (myopic regression). Stromal rethickening increased proportionally with the actual photoablation depth (r = 0.63, P<0.01); linear regression analysis suggested an average regrowth rate of 8% per year for the entire study group. Stromal rethickening was not associated with CMTF haze development over time, suggesting that haze and regression were caused by two independent wound healing mechanisms. In agreement with these findings, all "hazy" corneas showed increased numbers of anterior stromal wound healing keratocytes with increased reflectivity of both nuclei and cell bodies, suggesting that cellular-based reflections, as opposed to extracellular matrix deposition, are the major origin of increased corneal light scattering after PRK. CONCLUSIONS Taken together, these data indicate that keratocyte-mediated regrowth of the photoablated stroma appears to be the main cause of myopic regression in humans treated with a 6-mm diameter PRK, whereas hyperopic shifts appear to be a direct consequence of stromal thinning. By contrast, the corneal epithelium appeared to restore its preoperative thickness without contributing significantly to the refractive changes after PRK. Finally, this study also provides strong evidence that the development of haze after PRK is directly associated with increased cellular reflectivity from high numbers of wound healing keratocytes.
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Affiliation(s)
- T Moller-Pedersen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.
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112
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Vetrugno M, Quaranta GM, Maino A, Mossa F, Cardia L. Contrast sensitivity measured by 2 methods after photorefractive keratectomy. J Cataract Refract Surg 2000; 26:847-52. [PMID: 10889430 DOI: 10.1016/s0886-3350(00)00405-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To study contrast sensitivity in eyes that had flying-spot excimer laser photorefractive keratectomy (PRK) and to compare a subjective method (Vision Contrast Test System [VCTS] 6500) and an objective method (visual evoked potential [VEP]) of measuring contrast sensitivity. SETTING Istituto Clinica Oculistica, Università degli Studi, Bari, Italy. METHODS Contrast sensitivity changes over time were evaluated in 26 eyes. The baseline values were compared with measurements 3, 6, and 12 months after PRK using the VCTS 6500 and VEP. Contrast threshold and VEP amplitude were classified by myopic correction. RESULTS Contrast threshold values changed significantly over time (P <.001). Significant differences were found between mean contrast threshold preoperatively and 12 months postoperatively (P <.001) at all spatial frequencies. A significant relationship was established between baseline and 12 month measurements at 18 cycles per degree. Mean VEP amplitude measurements also changed significantly over time (P <.001) and showed a significant relationship between baseline and 12 month measurements (P <.001). A significant relationship was also established between baseline and 12 month VEP amplitude values at 100% of grating contrast. Patients with high myopia complained significantly more at a lower contrast threshold and at lower VEP amplitude values than patients with low myopia. CONCLUSIONS Three months after PRK, contrast threshold and VEP amplitude values were reduced. Partial recovery was established at 6 months, although patients reported permanent impairment under low-contrast conditions, especially if the myopia correction was more than 6.0 diopters.
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Affiliation(s)
- M Vetrugno
- Department of Ophthalmology and Otorhinolaryngology, University Hospital of Bari, Bari, Italy.
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113
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Eggink CA, Meurs P, Bardak Y, Deutman AF. Holmium Laser Thermal Keratoplasty for Hyperopia and Astigmatism After Photorefractive Keratectomy. J Refract Surg 2000; 16:317-22. [PMID: 10832980 DOI: 10.3928/1081-597x-20000501-04] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To report results of holmium laser thermal keratoplasty used to treat induced hyperopia and induced, as well as pre-existing astigmatism after photorefractive keratectomy. METHODS Sixteen eyes of 16 patients were included in this study. Contact holmium laser (Technomed Holmium 25) was used in 7 patients to correct hyperopia (8 spots at 8 or 9 mm) and in 9 patients to correct astigmatism (4 spots at 7, 8, or 9 mm). Follow-up evaluation was done after at least 6 months. The effectiveness, stability, and safety of the procedure were investigated. RESULTS Spherical correction was ineffective (1.00 D or less) when applied at the 9-mm diameter treatment zone. Spherical correction applied at the 8-mm diameter treatment zone was ineffective in 1 eye. Three eyes achieved 1.00 to 2.00 D change, but 2 of these eyes showed an induced astigmatic change as well. Correction of astigmatism at the 7-mm diameter treatment zone resulted in a 0 to 4.00 D cylinder component change. Treatment at the 8-mm diameter treatment zone showed a 0 to 1.50 D effect and at the 9-mm treatment zone, 0.25 to 1.50 D. All eyes that achieved significant improvement (1.00 D or more change in cylinder component) showed significant overcorrection in the first postoperative phase. There were no sight threatening complications. CONCLUSION Holmium laser thermal keratoplasty can be useful for the treatment of overcorrection and induced as well as pre-existing astigmatism after photorefractive keratectomy. However, predictability is low and astigmatism can be induced with the attempted spherical correction.
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Affiliation(s)
- C A Eggink
- Institute of Ophthalmology, University Hospital Nijmegen, The Netherlands
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114
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Alió JL, Artola A, Rodriguez-Mier FA. Selective zonal ablations with excimer laser for correction of irregular astigmatism induced by refractive surgery. Ophthalmology 2000; 107:662-73. [PMID: 10768327 DOI: 10.1016/s0161-6420(99)00152-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To demonstrate the safety and efficacy of selective zonal ablations with excimer laser for the correction of irregular astigmatism induced by refractive surgery. DESIGN Thirty-one eyes of 26 patients. Retrospective and noncomparative case series. METHODS The authors reviewed the medical results of the two series of consecutive cases of irregular astigmatism induced by refractive surgery. One group showed a topography map with a defined pattern: decentered ablation, decentered steep central island, central irregularity, and peripheral irregularity. The other group showed an irregular astigmatism without defined pattern. Selective zonal ablation was performed with a broad-beam excimer laser. Laser ablations were adjusted according to the Munnerlyn formula. A phototherapeutic keratectomy (PTK) mode was used in all cases without using viscous masking solution. MAIN OUTCOME MEASURES Uncorrected visual acuity, best spectacle-corrected visual acuity (BCVA), and Holladay diagnostic summary (Eye Sys 2.000) were considered before and after surgery to obtain the qualitative and quantitative characteristics of the visual acuity and corneal topography. The corneal uniformity index (CUI) was used to evaluate the corneal surface changes induced by the selective zonal ablations in the correction of irregular astigmatism. It proved to be a useful tool in the understanding of astigmatic changes when it is not possible to apply the vector analysis. RESULTS In group 1, the irregular astigmatism was significantly improved in 96.4% of cases. The CUI was improved from 58+/-0.3% to 87+/-0.8%, P < 0.005 (Student's t-test). The improvement of the BCVA was from 20/40+/-20/100 to 20/25+/-20/100, P < 0.005 (Student's t-test). The results obtained in group 2 were not clinically significant in terms of improvement of CUI and BCVA. CONCLUSIONS Using the corneal topographic map as a guide, selective zonal ablations with excimer laser can be used to create a more regular corneal surface, when a defined pattern of topographic irregularities can be defined.
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Affiliation(s)
- J L Alió
- Instituto Oftalmológico de Alicante, Spain.
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115
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Kang SW, Chung ES, Kim WJ. Clinical analysis of central islands after laser in situ keratomileusis. J Cataract Refract Surg 2000; 26:536-42. [PMID: 10771226 DOI: 10.1016/s0886-3350(99)00458-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To analyze the incidence and clinical characteristics of central islands after laser in situ keratomileusis (LASIK) and to elucidate factors associated with their formation. SETTING Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. METHODS Laser in situ keratomileusis was performed in 103 eyes of 61 patients with myopia ranging from -4.0 to -13.5 diopters (D) using the Hansatome (Chiron) and SVS Apex Plus (version 3.2.1) excimer laser (Summit Technology) in which the anti-central-island program was implemented. After 1 week, corneal topography (Orbscan, Orbtek) was done and manifest refraction and visual acuity were measured. RESULTS Postoperatively, the mean uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were 0.12 and 0.06 (logMAR scale), respectively, and the mean refractive error (spherical equivalent) was 0.07 D +/- 0.76 (SD). On topographic examination, a central island was defined as an area of higher refractive power of more than 1.5 D and 2.5 mm or more in diameter. Budding or isolated central islands were observed in 12 eyes of 12 patients (11.7%). The peak, height, and area of the islands were 41.5 +/- 3.1 D, 5.6 +/- 1. 9 D, and 3.5 +/- 1.1 mm(2), respectively. In the eyes with central islands, there were statistically significant differences in the postoperative change in UCVA and BCVA (P <.05). There was no significant correlation between the occurrence of a central island and preoperative refractive error, corneal thickness, age, or in sex and correction of astigmatism (P >.05). CONCLUSION Despite use of the anti-central-island pretreatment program, the occurrence of central islands after LASIK was significant, as in photorefractive keratectomy. Further studies of the effect of central islands on surgical results and clinical progress and measures to prevent the occurrence are needed.
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Affiliation(s)
- S W Kang
- Department of Ophthalmology, Samsung Medical Center School of Medicine, Sungkyunkwan University, Seoul, South Korea
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Bilgihan K, Ozdek S, Ozoğul C, Gurelik G, Bilgihan A, Hasanreisoğlu B. Topical vitamin E and hydrocortisone acetate treatment after photorefractive keratectomy. Eye (Lond) 2000; 14 ( Pt 2):231-7. [PMID: 10845023 DOI: 10.1038/eye.2000.60] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate the effects of topical vitamin E and hydrocortisone acetate treatments on corneal healing response after -10.0 D photorefractive keratectomy (PRK) in rabbits. METHODS Thirty-three New Zealand white rabbits were divided into four groups and -10 D PRK was performed under in vivo conditions. Following PRK, group 1 (n = 9) received no topical treatment and served as control. Group 2 (n = 8) received 0.1% hydrocortisone acetate ointment twice a day, group 3 (n = 8) received 1% vitamin E ointment and group 4 (n = 8) received both 0.1% hydrocortisone acetate and 1% vitamin E twice a day for a month. At the end of the third month, corneal haze was graded and the corneal hydroxyproline levels were measured, as a crude indicator of new collagen synthesis. Finally corneal samples were examined by transmission electron microscopy. RESULTS Non-homogeneously distributed strong haze was identified in group 1 which was greater than in the other groups; haze was least in groups 2 and 4. Corneal hydroxyproline levels were found to be significantly lower in groups 2, 3 and 4 compared with the control (Student's t-test, p < 0.05). Histopathologically, the most aggressive wound healing response was detected in group 1. The corneal wound healing response of group 2 was less than that of group 1 and equal to or more than that of group 4. CONCLUSIONS Deep corneal photoablation induces an aggressive healing response, and topical hydrocortisone acetate reduces this corneal wound healing effectively. The inhibitory effect of topical vitamin E on corneal wound healing seems to be less than that of hydrocortisone acetate, but combined treatment with these two drugs may have an additive effect in controlling corneal wound healing after PRK.
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Affiliation(s)
- K Bilgihan
- Gazi University Medical Faculty, Department of Ophthalmology, Ankara, Turkey.
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Affiliation(s)
- A Brahma
- Department of Ophthalmology, University of Dundee, Ninewells Hospital, Scotland, UK
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Abstract
PURPOSE To report the incidence of anisocoria after unilateral excimer laser photorefractive keratectomy (PRK) for myopia and subsequent corticosteroid therapy in a retrospective and prospective study and to explore possible etiologies. METHODS The horizontal pupil diameter was determined in 6 patients (6 eyes) at 21.8 +/- 12.6 months after unilateral wide-field excimer laser PRK (retrospective group) as well as in 8 consecutive patients (8 eyes) before and 3.4 +/- 2.9 months after unilateral PRK (prospective group). The Schwind-Keratom wide-field excimer laser was used. Measurements were done in an examination room using Rosenbaum card comparison pupillometry and with a Goldmann perimeter at 31.5 asb. In the prospective group, the effect of fitting a hard contact lens of zero diopter power and the application of 0.1% pilocarpine were evaluated. RESULTS Relative mydriasis was present in all treated eyes and the difference in pupil diameter between the two eyes measured 0.25 to 1.75 mm (retrospective group: +0.56 +/- 0.82 mm; prospective group: +0.72 +/- 0.29 mm). At the time of pupil measurement, the retrospective group had a significantly longer mean postoperative follow-up (21 mo) than the prospective group (3.4 mo) and significantly more eyes still received topical corticosteroid treatment (retrospective group, 1 of 6 eyes; prospective group, 7 of 8 eyes). The amount of anisocoria did not correlate with the applied laser energy, ablation depth, or refractive change, but showed a negative correlation with increasing time after PRK. Neither hard contact lens fitting nor pilocarpine 0.1% reduced the amount of anisocoria significantly. CONCLUSION Unilateral PRK with wide-field excimer laser ablation and subsequent application of topical corticosteroids regularly resulted in a relative pupillary mydriasis. Neither an altered corneal profile nor parasympathetic denervation is responsible for this. Weakening of the pupillary sphincter of the treated eye may cause this phenomenon.
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Affiliation(s)
- G Geerling
- Department of Ophthalmology, Medical University Lübeck, Germany.
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Tabbara KF, El-Sheikh HF, Sharara NA, Aabed B. Corneal haze among blue eyes and brown eyes after photorefractive keratectomy. Ophthalmology 1999; 106:2210-5. [PMID: 10571361 DOI: 10.1016/s0161-6420(99)90507-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND To compare the incidence and severity of corneal haze after photorefractive keratectomy (PRK) among white patients with blue eyes and Saudi patients with brown eyes. DESIGN Retrospective, nonrandomized, comparative trial. PARTICIPANTS A total of 150 patients (71 females and 79 males) were included in this study. Two hundred sixty-six eyes of 150 patients were subjected to PRK. One hundred blue eyes of 50 white patients and 166 brown eyes of 100 Saudi patients were included in this study. METHODS Two hundred sixty-six eyes of 150 patients were subjected to PRK with the Chiron Technolas Keracor 117C for the correction of myopia and astigmatism. MAIN OUTCOME MEASURES All patients had complete ophthalmologic examinations, visual acuity testing, intraocular pressure, pachymetry, corneal haze assessment (0-4+), and computerized corneal topography. RESULTS There were 266 eyes of 150 patients with 100 blue irides and 166 brown irides. The spherical equivalent was -0.50 diopter (D) to -8.75 D. The mean postoperative spherical equivalent at 6 months was -0.063 D (standard deviation [SD], +/-0.595) in blue eyes compared to -0.28 D (SD, +/-0.683) in brown eyes (P = 0.006). Ninety-five (95%) of 100 of the blue eyes achieved +/- 1 D of attempted correction compared to 148 (89.2%) of the 166 brown eyes. All patients with blue eyes had a visual acuity of 20/30 or better compared to 153 (92.2%) of the 166 brown eyes (P = 0.009). Forty-eight (18.04%) eyes had minimal to mild haze, 3 (1.12%) eyes had moderate haze, and 2 (0.75%) eyes had severe haze. The incidence of corneal haze among brown eyes was 48 (28.9%) of 166 eyes compared to 5 (5%) of 100 in blue eyes (P < 0.001). The difference remained significant after adjustment for age and gender with a P value of 0.0283. The relative risk for developing haze in brown eyes was found to be 7.72. CONCLUSION The incidence of corneal haze after PRK was significantly higher among Saudi patients with brown irides than among white patients with blue irides. This suggests that racial factors may play a role in the development of corneal haze.
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Affiliation(s)
- K F Tabbara
- The Eye Center and The Eye Foundation for Research in Ophthalmology, Riyadh, Saudi Arabia
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Artola A, Ayala MJ, Claramonte P, Pérez-Santonja JJ, Alió JL. Photorefractive keratectomy for residual myopia after cataract surgery. J Cataract Refract Surg 1999; 25:1456-60. [PMID: 10569159 DOI: 10.1016/s0886-3350(99)00233-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the effectiveness, predictability, and safety of photorefractive keratectomy (PRK) for correcting residual myopia and myopic astigmatism after cataract surgery with intraocular lens implantation. SETTING Refractive Surgery and Cornea Unit, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS Thirty consecutive eyes (30 patients) had PRK for residual myopia after cataract surgery. Surface PRK with a VISX Twenty-Twenty excimer laser was used in all patients. Follow-up was 1 year. RESULTS Before PRK, no eye had an uncorrected visual acuity (UCVA) of 20/40 or better. Twelve months after PRK, 16 eyes (53.33%) had a UCVA of 20/40 or better. After PRK, best corrected visual acuity (BCVA) improved 1 line or more in 14 eyes (46.66%) over the preoperative values, and 15 eyes (50.00%) had the same BCVA as before PRK. Mean pre-PRK refraction of -5.00 diopters (D) +/- 2.50 (SD) decreased significantly to -0.25 +/- 0.50 D at 12 months (P < .001). At 12 months, the spherical equivalent was within +/- 1.00 D of emmetropia in 27 eyes (90.00%). No vision-threatening complications occurred. CONCLUSION Photorefractive keratectomy was an effective, predictable, and safe procedure for correcting residual myopia and myopic astigmatism after cataract surgery.
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Affiliation(s)
- A Artola
- Refractive Surgery and Cornea Department, Alicante Institute of Ophthalmology, Miguel Hernández University School of Medicine, Spain
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Reviglio VE, Luna JD, Rodríguez ML, García FE, Juárez CP. Laser in situ keratomileus using the LaserSight 200 laser: results of 950 consecutive cases. J Cataract Refract Surg 1999; 25:1062-8. [PMID: 10445191 DOI: 10.1016/s0886-3350(99)00121-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To examine the refractive outcome in 950 consecutive eyes having laser in situ keratomileusis (LASIK) by 1 surgeon with experience in keratomileusis. SETTING Outpatient excimer laser surgical facility. METHODS This study comprised 950 consecutive eyes of 475 patients having LASIK as a primary procedure with a LaserSight 200 excimer laser (8.51 software). A nasal hinged flap and a Chiron microkeratome were used. Preoperative cycloplegic refraction was done only in patients younger than 25 years and in all hyperopic cases. Subjective preoperative and postoperative manifest refractions were done after autorefractometry in all cases. In cases of hyperopia, the software was modified by adding 30% to the refractive error. Enhancement results are not included. RESULTS Of the 950 eyes, 893 (94.00%) were myopic and 57 (6.00%), hyperopic. In the low myopia group (1.00 to 3.99 D) of 223 eyes (24.97%), mean spherical equivalents (SEs) were -2.90 D +/- 0.56 (SD) preoperatively, -0.46 +/- 0.6 D 3 months postoperatively, and -0.41 +/- 0.5 D 6 months postoperatively. In the moderate myopia group (4.00 to 5.99 D) of 205 eyes (22.96%), respective mean SEs were -4.90 +/- 0.7 D, -0.90 D +/- 0.9 D, and -0.67 +/- 0.7 D. In the high myopia group (6.00 to 9.99) of 266 eyes (25.30%), the respective means were -7.70 +/- 1.3 D, -0.76 +/- 0.99 D, and -0.60 +/- 0.8 D. In the extreme myopia group (10.21 to 30.00) of 199 eyes (22.28%), the respective means were -13.30 +/- 2.9 D, -1.30 +/- 1.4 D, and -1.13 +/- 1.3 D. For the entire myopic group, the mean astigmatism was +1.55 +/- 1.38 D, +1.09 +/- 0.92 D, and +0.87 +/- 0.77 D, respectively. The low hyperopia group (1.00 to 2.99 D) of 39 eyes (68.42%) had a mean preoperative SE of +1.80 +/- 0.59 D and mean postoperative SEs of +1.00 +/- 0.76 D at 3 months and +1.16 +/- 0.52 D at 6 months. The respective means in the moderate hyperopia group (3.00 to 6.00) of 18 eyes (31.57%) were +4.62 +/- 1.19 D, +3.71 +/- 1.12 D, and +4.00 +/- 1.07 D. CONCLUSIONS Laser in situ keratomileus for myopia using the LaserSight 200 excimer laser was stable with time and safe for the correction of different degrees of myopia. In the hyperopic group, marked regression occurred in a large percentage of patients. Thus, we will not perform LASIK for hyperopia until the software improves.
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Ahn CS, Clinch TE, Moshirfar M, Weis JR, Hutchinson CB. Initial results of photorefractive keratectomy and laser in situ keratomileusis performed by a single surgeon. J Cataract Refract Surg 1999; 25:1048-55. [PMID: 10445189 DOI: 10.1016/s0886-3350(99)00127-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To determine the safety and efficacy of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) early in a surgeon's experience. SETTING Ophthalmology Department, John A. Moran Eye Center, Salt Lake City, Utah, USA. METHODS Between October 1995 and April 1997, a retrospective analysis was performed of 200 eyes in 128 patients who had PRK or LASIK with a follow-up of at least 3 months. The mean age was 38.1 years +/- 10.4 (SD) in the PRK group and 42.3 +/- 10.1 years in the LASIK group. There were 36 women and 30 men in the former and 32 women and 30 men in the latter. Photorefractive keratectomy, PRK/astigmatic keratotomy (AK), LASIK, or LASIK/AK was performed with the Summit Omnimed excimer laser. Preoperative evaluation included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, tonometry, and computerized videokeratography. At 1, 3, and 6 months, UCVA, BSCVA, mean spherical equivalent (SE), astigmatism, corneal haze, subjective vision (day, night, glare, and halo), and complications were measured. RESULTS Mean SE was 0.16 +/- 0.82 diopter (D) in the PRK group and -0.09 +/- 0.63 D in the LASIK group at 1 month (P < .05), -0.18 +/- 0.66 D and -0.16 +/- 0.58 D, respectively, at 3 months, and -0.33 +/- 0.73 D and -0.09 +/- 0.62 D, respectively, at 6 months. Achieved correction was similar in the 2 groups. Mean BSCVA was 22.8 +/- 6.0 in the PRK group and 22.2 +/- 5.3 in the LASIK group at 1 month, 21.1 +/- 6.0 and 21.1 +/- 3.1, respectively, at 3 months, and 19.8 +/- 3.5 and 22.9 +/- 5.2, respectively, at 6 months (P < .005). Mean surface regularity index was 0.68 +/- 0.40 in the PRK group and 0.86 +/- 0.41 in the LASIK group at 1 month, 0.54 +/- 0.26 and 0.72 +/- 0.37, respectively, at 3 months (P < .05), and 0.49 +/- 0.27 and 0.84 +/- 0.42, respectively, at 6 months. Mean surface asymmetry index was 0.71 +/- 0.43 in the PRK group and 0.55 +/- 0.21 in the LASIK group at 1 month (P < .05), 0.53 +/- 0.24 and 0.51 +/- 0.23, respectively, at 3 months, and 0.46 +/- 0.19 and 0.64 +/- 0.54, respectively, at 6 months. The subjective parameters between the groups were significantly different only at 6 months; patients in the PRK group reported better day and night vision. CONCLUSION With careful preparation and proper training, PRK and LASIK appear to be safe and efficacious even during the surgeon's early learning phases.
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Affiliation(s)
- C S Ahn
- University of Utah Health Science Center, Salt Lake City, USA
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Kato T, Nakayasu K, Ikegami K, Obara T, Kanayama T, Kanai A. Analysis of glycosaminoglycans in rabbit cornea after excimer laser keratectomy. Br J Ophthalmol 1999; 83:609-12. [PMID: 10216064 PMCID: PMC1723022 DOI: 10.1136/bjo.83.5.609] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS The biochemical basis for the development of subepithelial opacity of the cornea after excimer laser keratectomy has yet to be fully defined. The aim of this study was to evaluate the alterations of glycosaminoglycans (GAGs) after excimer laser keratectomy. METHODS Rabbit corneas were harvested on days 5, 10, 20, and 30 after excimer laser photoablation. The amount of main disaccharide units was determined by high performance liquid chromatography (HPLC). In addition, immunohistochemical studies were performed on corneal sections 20 days after the ablation. RESULTS The concentrations of DeltaDi-0S at 5 and 10 days were significantly lower than before the ablation. DeltaDi-6S showed a significant increase 5 days after the ablation but DeltaDi-4S did not show any significant change. There was a significant increase in DeltaDi-HA at 20 and 30 days after ablation. In immunohistochemistry, the positive staining for DeltaDi-6S and hyaluronic acid was observed in the subepithelial region. These immunohistochemical results were well correlated with the HPLC findings. CONCLUSIONS The increase in chondroitin-6 sulphate and hyaluronic acid may be related to corneal subepithelial opacity after excimer laser keratectomy.
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Affiliation(s)
- T Kato
- Department of Ophthalmology, Juntendo University, Tokyo, Japan
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Alió JL, de la Hoz F, Pérez-Santonja JJ, Ruiz-Moreno JM, Quesada JA. Phakic anterior chamber lenses for the correction of myopia: a 7-year cumulative analysis of complications in 263 cases. Ophthalmology 1999; 106:458-66. [PMID: 10080200 DOI: 10.1016/s0161-6420(99)90103-3] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To perform a prospective, clinical trial to determine the potential cumulative complications of patients implanted with angle-supported phakic intraocular lenses (PIOLs) for the correction of myopia. DESIGN Nonrandomized, prospective, comparative trial. PARTICIPANTS Two hundred sixty-three eyes of 160 consecutive patients were included. INTERVENTION Angle-supported anterior chamber intraocular lenses were implanted into phakic eyes. MAIN OUTCOME MEASURES Night halos and glare were recorded. Central endothelial cell count, postoperative inflammation, applanation tonometry, cataract development, retinal detachment, and pupil ovalization were recorded by the same physician. RESULTS Night halos and glare were reported as significant by 20.2% at 1 year and 10% at year 7 of follow-up. This complication was significantly lower in the larger optical zone PIOL (ZSAL-4) than in the ZB5M/ZB5MF group (P < 0.05). Acute postoperative iritis was observed in 4.56% of cases. High intraocular pressure that required antiglaucoma medications appeared in 7.2% of cases. Central corneal endothelial cell density was significantly decreased at postoperative month 3 (P < 0.0001). The percentages of cell loss were 3.76% at month 3 and 1.83% at year 1, and then the percentages decreased by 1.37% more at year 2, 0.72% at year 3, 0.3% at year 4, 0.6% at year 5, 0.4% at year 6, and 0.56% at year 7. The total cumulative loss of central endothelial cells after 7 years was 8.37%. Pupil ovalization was present in 5.9% of cases, although smaller degrees of this complication were observed in another 10.3%. Retinal detachment appeared in 3% of cases. The PIOL explantation was decided in 11 cases (4.18%) because of cataract development (9 cases) and extreme pupil ovalization associated with severe glare (2 cases). The Kaplan-Meier cumulative survival analysis study showed an expected period free from complication of 86.5% for IOP elevation, 98.75% for endothelial cell count inferior to 1500 cells/mm2, 86.97% for pupil ovalization, 95.43% for retinal detachment, and 89.02% for explantation. CONCLUSIONS Angle-supported PIOL appeared to be well tolerated by the corneal endothelium with a low rate of other complications. Pupil ovalization seemed to be a specific problem for this type of PIOL.
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Affiliation(s)
- J L Alió
- Instituto Oftalmológico de Alicante, Spain
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Kremer I, Kaplan A, Novikov I, Blumenthal M. Patterns of late corneal scarring after photorefractive keratectomy in high and severe myopia. Ophthalmology 1999; 106:467-73. [PMID: 10080201 DOI: 10.1016/s0161-6420(99)90104-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To study the correlation between scarring 1 year after photorefractive keratectomy (PRK), final refraction, and degree of myopia. DESIGN A retrospective, noncomparative case series. PARTICIPANTS One hundred twenty eyes of 78 patients underwent PRK for high and severe myopia. Thirty-nine eyes had a pre-PRK spherical equivalent (SE) between -9.5 and -18.25 diopters (D) (severe myopia). Eighty-one eyes had a pre-PRK SE between -6.25 and -9.25 D (high myopia). Follow-up time ranged between 12 and 37 months with a mean of 18.2 months. INTERVENTION Multizone PRK with the VISX 20/20 excimer laser. MAIN OUTCOME MEASURES Corneal scarring, final best-corrected visual acuity (BCVA), and refraction. RESULTS There were 71.7% of eyes with severe myopia and 60.5% of eyes with high myopia found to have any pattern of stromal scarring, which was classified as focal, semiannular, annular, and discoid. Discoid scars were rare (6.6%) and found in 12.8% of severe myopic eyes compared to 3.7% of high myopic eyes. Only 50% of the eyes with a discoid scar achieved final BCVA between 6/6 and 6/9 compared to 81.6% of the eyes with a clear cornea. The severe myopic eyes with a discoid scar had the highest level of final undercorrection (-5.0 D) compared to a maximum of -1.5 D in the high myopia group. The severe myopic eyes with a discoid scar had a higher number of retreatments (4 of 5) compared to the high myopia group (1 of 3). Other types of scars were less clinically significant. CONCLUSIONS Photorefractive keratectomy was efficient in the correction of high myopia but less so in severe myopia, in which discoid scarring was more frequent and more clinically significant, being associated with significant regression. Other types of scarring were less clinically significant.
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Affiliation(s)
- I Kremer
- Ein Tal Eye Center, Tel Aviv, Israel
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Excimer laser photorefractive keratectomy (PRK) for myopia and astigmatism11Prepared by the Committee on Ophthalmic Procedures Assessment Refractive Surgery Panel, Christopher J. Rapuano, MD, Chair, and approved by the American Academy of Ophthalmology’s Board of Trustees December 14, 1998. Ophthalmology 1999. [DOI: 10.1016/s0161-6420(99)90085-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Abstract
PURPOSE To retrospectively analyze a group of patients to determine whether their induced astigmatism was caused by asymmetry in the laser beam, asymmetry in ablation rates, or wound healing in different corneal meridians. SETTING Single-center physician office. METHODS In this study, 146 eyes of 116 patients who had photorefractive keratectomy (PRK) for myopia with the Apex laser (Summit Technology) were retrospectively identified. In 28 eyes, the patient's chair had been rotated 90 degrees from its usual position under the laser. The vector-summated mean change in astigmatism in eyes with the chair rotated 90 degrees was compared with that in a group of control eyes in which the chair was in the usual position. RESULTS The vector-summated mean change in the control eyes was 0.30 diopter (D) at 83 degrees. Forty-eight of 113 eyes (42.5%) had induced with-the-rule (WTR) astigmatism, and 14 of 113 eyes (12.4%) had induced against-the-rule (ATR) astigmatism. In the eyes in which the chair was rotated 90 degrees, vector-summated mean change was 0.10 D at 13 degrees (P < .0005). One of 27 eyes (3.7%) had induced WTR astigmatism, and 13 of 27 eyes (48.1%) had induced ATR astigmatism (P < .001, chi-square). CONCLUSION Astigmatism induced by myopic PRK with the Apex laser was small. The axis of induced astigmatism rotated 90 degrees when the patient's chair was rotated, implying that it is inhomogeneities in the beam rather than meridional asymmetry in ablation rates or wound healing that are responsible for induced astigmatism.
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Affiliation(s)
- T Onclinx
- Maloney Vision Institute, Los Angeles, California 90024, USA
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Kapadia MS, Meisler DM, Wilson SE. Epithelial removal with the excimer laser (laser-scrape) in photorefractive keratectomy retreatment. Ophthalmology 1999; 106:29-34. [PMID: 9917777 DOI: 10.1016/s0161-6420(99)90002-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To retrospectively evaluate refractive and topographic outcomes after excimer laser photorefractive keratectomy (PRK) retreatment using the laser-scrape technique for epithelial removal. DESIGN Retrospective clinical study. PARTICIPANTS Thirty eyes of patients who had PRK retreatment for undercorrection after primary PRK were examined. INTERVENTION The PRK retreatment was performed using a laser-scrape technique in which the excimer laser was used to remove the majority of the epithelium overlying the anterior stromal surface before additional PRK ablation. MAIN OUTCOME MEASURES Uncorrected visual acuity, best-corrected visual acuity (BCVA), surface regularity index (SRI), and surface asymmetry index were measured. RESULTS Primary PRK was performed for myopia of -5.1 +/- 1.7 diopters (range, -1.1 to -7.5 diopters). Mean spherical equivalent (SE) was -1.3 +/- 0.4 diopters (range, -0.6 to -2.0 diopters) before retreatment. Mean SE 6 months after retreatment decreased to +0.1 +/- 0.4 diopter (range, +1.25 to -0.75 diopters; P < 0.0001). Four eyes (15%) were more than +0.5 diopter overcorrected at 6 months. Ninety-six percent of eyes achieved mean SE within +/- 1 diopter and 77% within +/- 0.5 diopter of emmetropia after retreatment. Visual acuity improved significantly 6 months after reablation (P < 0.0001) with 100% 20/40 or better and 73% 20/25 or better without correction. Final BCVA also improved compared with before retreatment (P = 0.02). Twelve eyes gained 1 line of BCVA and no eye lost more than 1 line of BCVA. The SRI before retreatment was 0.6 +/- 0.3 (range, 0.0-0.9) and remained the same 0.6 +/- 0.2 (range, 0.1-1.0; P = 0.8), 6 months after retreatment. CONCLUSION Excimer laser PRK retreatment using the laser-scrape technique for epithelial removal is an accurate and safe procedure for treating undercorrection of eyes after PRK for low-to-moderate myopia.
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Affiliation(s)
- M S Kapadia
- Eye Institute, Cleveland Clinic Foundation, Ohio, USA
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Böhnke M, Thaer A, Schipper I. Confocal microscopy reveals persisting stromal changes after myopic photorefractive keratectomy in zero haze corneas. Br J Ophthalmol 1998; 82:1393-400. [PMID: 9930270 PMCID: PMC1722439 DOI: 10.1136/bjo.82.12.1393] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS Micromorphological examination of the central cornea in myopic patients 8-43 months after excimer laser photorefractive keratectomy (PRK), using the slit scanning confocal microscope. METHODS Patients were selected from a larger cohort of individuals on the basis of full corneal clarity (haze grading 0 to +1; mean 0.3) and their willingness to participate in the study. 15 eyes of 10 patients with myopic PRK (-4 to -11 D; mean 6.7) and an uneventful postoperative interval of 8-43 months (mean 26) were examined. Contact lenses had been worn by eight of the 10 patients for 4-11 years (mean 6.7) before surgery. Controls included the five untreated fellow eyes of PRK patients, 10 healthy, age matched volunteers without a history of ocular inflammation or contact lens wear, and 20 patients who had worn rigid gas permeable (n = 10) or soft contact lenses (n = 10) for 2-11 years. Subjects were examined with a real time flying slit, scanning confocal microscope using x25 and x50 objectives. RESULTS In PRK treated patients and contact lens wearers, basal layer epithelial cells sporadically displayed enhanced reflectivity. The subepithelial nerve plexus was observed in all individuals, but was usually less well contrasted in the PRK group, owing to the presence of a very discrete layer of subepithelial scar tissue, which patchily enhanced background reflectivity. Within all layers of the stroma, two distinct types of abnormal reflective bodies were observed in all PRK treated eyes, but in none of the controls. One had the appearance of long (> = 50 microns), slender (2-8 microns in diameter) dimly reflective rods, which sometimes contained bright, punctate, crystal-like inclusions, arranged linearly and at irregular intervals. The other was shorter (< 25 microns), more slender in form (< 1 micron in diameter), and highly reflective; these so called needles were composed of crystal-like granules in linear array, with an individual appearance similar to the bright punctate inclusions seen in rods, but densely packed. Both of these unusual structures were confined, laterally, to the ablated area, but were otherwise distributed throughout all stromal layers, with a clear predominance in the anterior ones. These rods and needles were observed in all PRK treated corneas, irrespective of previous contact lens wear. On the basis of qualitative inspection, the incidence of rods and needles did not appear to correlate with either the volume of tissue ablated or the length of the postoperative interval. In contact lens wearing controls, highly reflective granules, reminiscent of those from which the needles were composed, were found scattered as isolated entities throughout the entire depth and lateral extent of the corneal stroma, but rods and needles were never encountered. The corneal endothelium exhibited no obvious abnormalities. CONCLUSION Confocal microscopy 8-43 months after PRK revealed belated changes in the corneal stroma. These were manifested as two distinct types of abnormal reflective bodies, which had persisted beyond the stage when acute wound healing would have been expected to be complete. The clinical significance of these findings in the context of contrast visual acuity and long term status of the cornea is, as yet, unknown.
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Affiliation(s)
- M Böhnke
- University of Bern, Department of Ophthalmology, Switzerland
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130
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MD AO, Aras C, Sener B, Bahcecioglu H. Two-Year Results of Photorefractive Keratectomy With Scanning Spot Ablation for Myopia of Less Than -6.0 Diopters. Ophthalmic Surg Lasers Imaging Retina 1998. [DOI: 10.3928/1542-8877-19981101-07] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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131
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Pérez-Santonja JJ, Linna TU, Tervo KM, Sakla HF, Alió y Sanz JL, Tervo TM. Corneal Wound Healing After Laser in situ Keratomileusis in Rabbits. J Refract Surg 1998; 14:602-9. [PMID: 9866098 DOI: 10.3928/1081-597x-19981101-06] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The aim of this study was to characterize the cell biology of wound healing in rabbit corneas subjected to laser in situ keratomileusis (LASIK). METHODS Rabbit corneas underwent LASIK with various multizone photoablations or only a lamellar keratotomy followed by repositioning of the flap. We looked for indications for an active wound healing process. Immunohistochemistry for the extradomain A cellular fibronectin (EDA-cFn) or tenascin (Tn) and routine histology were examined. RESULTS Four days after LASIK or lamellar keratotomy followed by repositioning of the flap, epithelial plugs and prominent keratocytes as well as Tn and EDA-cFn immunoreactions-indicative of a wound-healing process-appeared in the wound margins. Epithelial plugs were less conspicous, and prominent, presumably activated, keratocytes were no longer identified at the wound margin at 2.5 and 5 months after wounding. However, EDA-cFn and Tn immunoreactivities could still be observed. Only the stromal cells located in the periphery of the flap and in relatively close contact with the epithelium were surrounded by scar tissue expressing immunoreactivity for EDA-cFn or Tn. The central corneal stroma was devoid of scar tissue. CONCLUSION Results indicate that the wound healing reaction after LASIK takes place only at the periphery of the microkeratome wound, leaving the central optical zone clear.
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132
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Pietilä J, Mäkinen P, Pajari S, Uusitalo H. Photorefractive Keratectomy for -1.25 to -25.00 Diopters of Myopia. J Refract Surg 1998; 14:615-22. [PMID: 9866100 DOI: 10.3928/1081-597x-19981101-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND We evaluated prospectively the efficacy, predictability, stability, and safety of photorefractive keratectomy (PRK) for myopia. METHODS Three hundred sixty-nine eyes of 257 patients were treated with an Aesculap-Meditec MEL 60 excimer laser. Treated eyes were divided into 3 groups: low myopes (-1.25 to -6.00 D), 226 eyes; medium myopes (-6.10 to -10.00 D), 104 eyes; high myopes (-10.10 to -25.00 D), 39 eyes. Follow-up at 12 months was available for 348 eyes (94%). RESULTS One year after surgery the number of eyes within +/- 1.00 D of emmetropia was 182 (86.7%) for low myopes, 43 (40.5%) for medium myopes, and 12 (30.8%) for high myopes. Values for +/- 0.50 D were low: 142 (67.6%), medium: 29 (29.3%), and high: 9 (23.1%). Three eyes with low myopia (1.4%) and 5 eyes with medium myopia (5.1%) lost 2 or more lines of spectacle-corrected visual acuity. None of the high myopes lost 2 or more lines. Uncorrected visual acuity of 20/20 or better was achieved in 82 eyes (39%) with low myopia; 20/40 or better was achieved in 183 eyes (87.1%). Five eyes (5.1%) of medium myopes achieved 20/20 or better; 52 eyes (52.5%) with medium myopia achieved 20/40 or better. Zero eyes with high myopia achieved 20/20 or better; 11 eyes (28.8%) achieved 20/40 or better. CONCLUSION Photorefractive keratectomy proved to be an effective method to correct myopia up to -6.00 D. For myopia greater than -6.00 D, good results were achieved in most eyes when myopia was less than -10.00 D, but efficacy and predictability decrease. To avoid systematic undercorrection, slight overcorrection must be attempted with the Aesculap-Meditec MEL 60 excimer laser for the treatment of myopia.
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Affiliation(s)
- J Pietilä
- Department of Ophthalmology, University of Tampere, Medical School, Finland
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133
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Steinert RF, Bafna S. Surgical correction of moderate myopia: which method should you choose? II. PRK and LASIK are the treatments of choice. Surv Ophthalmol 1998; 43:157-79. [PMID: 9841455 DOI: 10.1016/s0039-6257(98)00027-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- R F Steinert
- Center for Eye Research and Education, Ophthalmic Consultants of Boston, MA., USA
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134
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Abstract
PURPOSE To compare the predictability, safety, and stability of photorefractive keratectomy (PRK) in patient groups with low, moderate, and high myopia. The astigmatic component of these corrections was also evaluated. METHODS In 110 patients, 110 consecutive eyes were operated with a VISX 20/20 excimer laser using standard settings and a 6 mm ablation zone for PRK. The eyes were divided into three groups. In low myopia group (N = 52) the intended correction ranged from -1.50 to -6.00 D (mean -4.28 +/- 1.29 D), in the moderate myopia group (N = 34) from -6.10 to -8.00 D (mean -7.05 +/- 0.70 D), and in the high myopia group (N = 24) from -8.10 to -11.50 D (mean -9.40 +/- 1.13 D). Twenty-seven eyes had 0.75 D of preoperative myopic astigmatism. All patients were followed for 12 months and 36% (N = 40) were available for the 24-month follow-up examination. RESULTS At 12 months the spherical equivalent manifest refraction was within 0.50 D of intended refraction in 58% (N = 30) of eyes in the low myopia group, 50% (N = 17) in the moderate myopia group, and 29% (N = 7) in the high myopia group. Eighty-seven percent (N = 45) in low, 79% (N = 27) in moderate, and 67% (N = 16) in the high myopia group were within 1.00 D of intended refraction. At 12 months, 88% (N = 46) of the eyes with low myopia, 68% (N = 23) with moderate myopia, and 68% (N = 16) with high myopia achieved uncorrected visual acuity of 20/40 or better, while 6% (N = 16) of the eyes lost and 4% (N = 4) gained two or more lines of Snellen visual acuity. Uncorrected visual acuity of 20/20 or better at 12 months was achieved by 58% (N = 30) of low myopes, 26% (N = 9) of moderate myopes, and 33% (N = 8) of high myopes; 20/25 or better by 71% (N = 37) of low myopes, 39% (N = 13) of moderate myopes, and 42% (N = 10) of high myopes. Overcorrection (> 0.25 D) was detected at 12 months in 31% (N = 16) with low, 38% (N = 13) with moderate, and 67% (N = 16) with high baseline myopia, with statistically significant differences between the low and high myopia groups. CONCLUSION In all groups, the safety of PRK was satisfactory, without major complications; in the high myopia group where corrections exceeded 8.0 D (mean -9.40 +/- 1.13 D) the procedure was only slightly more unpredictable than in low and moderate myopia at 1 year.
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Affiliation(s)
- T H Tuunanen
- Department of Ophthalmology, University of Helsinki, Finland
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135
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Abstract
A 41-year-old man who had photorefractive keratectomy (PRK) for myopia developed corneal haze. After intensive treatment with topical corticosteroids, he developed elevated intraocular pressure and optic nerve damage. Because of an inadequate response to steroid discontinuation and medical treatment, the patient required a glaucoma filtering procedure. Corticosteroid-induced glaucoma is a possible complication of the treatment often associated with PRK. Careful patient screening and disclosure of this risk are imperative.
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Affiliation(s)
- J Morales
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock 79430, USA
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136
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Knorz MC, Wiesinger B, Liermann A, Seiberth V, Liesenhoff H. Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism. Ophthalmology 1998; 105:932-40. [PMID: 9593400 DOI: 10.1016/s0161-6420(98)95040-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE This study evaluated the predictability, stability, and safety of laser in situ keratomileusis (LASIK) in myopia and myopic astigmatism. DESIGN The study design was a prospective, unmasked, nonrandomized clinical trial. PARTICIPANTS Participating were 25 patients with myopia (37 eyes) with astigmatism of less than 1.00 diopter (D), divided into 3 subgroups (-5.00 to -9.90 D, 8 eyes; -10.00 to -14.90 D, 10 eyes; -15.00 to -29.00 D, 19 eyes), and 37 patients with myopia (56 eyes) with corneal astigmatism of 1.00 to 4.50 D, divided into 3 subgroups (-5.00 to -9.90 D, 12 eyes; -10.00 to -14.90 D, 24 eyes; -15.00 to -29.00 D, 20 eyes). INTERVENTION LASIK was performed using the Automatic Corneal Shaper and the Keracor 116 excimer laser. MAIN OUTCOME MEASURES Visual acuity, manifest refraction, central corneal islands, ablation decentration, and patient satisfaction were measured. RESULTS At 12 months, predictability, regression between 1 and 12 months, uncorrected visual acuity (UCVA), loss of two or more lines of corrected visual acuity, and patient satisfaction of the spherical (toric) groups are reported. Subgroups -5.00 to -9.90 D: 100% (75%) +1.00 D; regression less than or equal to 1.00 D in 100% (91.7%); UCVA greater than or equal to 20/40 in 87.5% (70%); none lost two or more lines; 100% (84%) highly satisfied. Subgroups -10.00 to -14.90 D: 60% (78.3%) +/-1.00 D; regression less than or equal to 1.00 D in 100% (87%); UCVA greater than or equal to 20/40 in 77.8% (86.4%); 10% (4.3%) lost two lines; 90% (91%) highly satisfied. Subgroups -15.00 to -29.00 D: 38.9% (21.4%) +/-1.00 D; regression less than or equal to 1.00 D in 72.2% (64.3%); UCVA greater than or equal to 20/40 in 33.3% (40%); 5.6% (7.1%) lost two lines; 78% (50%) highly satisfied. Differences of predictability and change of manifest refraction between subgroups of -5.00 to -9.90 D and -15.00 to -29.00 D were statistically significant. Central islands (decentrations) were observed in 17% (5.6%) of eyes of the spherical and in 16% (4.1%) of the toric group. Overall, the corneal interface was visible in 8.2%. CONCLUSIONS The LASIK method used in this study showed stability of manifest refraction and adequate uncorrected central visual acuity in a large percentage of patients with myopia up to -15.00 D. Corneal stability was not as uniform. Central corneal islands were observed in a sizable minority of patients despite pretreatment. For myopia greater than 15.00 D, accuracy and patient satisfaction were sufficiently poor to advise against using the authors' treatment technique in these groups. Visually significant microkeratome and laser-related problems were noted in a smaller percentage of patients. Patients with astigmatism correction were less pleased with results than were patients who received spherical corrections.
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Affiliation(s)
- M C Knorz
- Department of Ophthalmology, Klinikum Mannheim, Germany
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137
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Alió JL, Artola A, Claramonte PJ, Ayala MJ, Sánchez SP. Complications of photorefractive keratectomy for myopia: two year follow-up of 3000 cases. J Cataract Refract Surg 1998; 24:619-26. [PMID: 9610444 DOI: 10.1016/s0886-3350(98)80256-3] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the results and complications of photorefractive keratectomy (PRK) for myopia. SETTING Alicante Institute of Ophthalmology, University of Alicante, Spain. METHODS This prospective study evaluated the results and complications of the first 3000 cases of PRK performed with a VISX Twenty-Twenty excimer laser. Myopia ranged from -1.0 to -14.0 diopters (D) and astigmatism, from -1.0 to -5.0 D. Follow-up was 2 years. RESULTS Ten eyes (0.7%) lost two or more lines of best corrected visual acuity 1 year after surgery. Retreatment for undercorrection or regression was done in 7.41% in the low myopia group and 38.69% in the high myopia group. Central islands, which could be detected only on videokeratoscopy, occurred frequently but influenced the refractive and visual outcomes in few cases. Severe haze was present in 17 eyes only after 1 year follow-up. There were no cases of progressive hyperopia. Other complications such as eccentric ablation producing astigmatism (n = 15), delayed re-epithelialization, or recurrent corneal erosion were rare. CONCLUSION There were few complications after PRK in 3000 eyes. With proper patient selection, PRK can be considered relatively safe compared with other refractive procedures.
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Affiliation(s)
- J L Alió
- Department of Pathology and Surgery, University of Alicante, Spain
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138
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Chang JH, Kook MC, Lee JH, Chung H, Wee WR. Effects of synthetic inhibitor of metalloproteinase and cyclosporin A on corneal haze after excimer laser photorefractive keratectomy in rabbits. Exp Eye Res 1998; 66:389-96. [PMID: 9593632 DOI: 10.1006/exer.1997.0415] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To evaluate the effects of synthetic inhibitor of metalloproteinase (SIMP) and cyclosporin A (CsA) on corneal haze after excimer laser photorefractive keratectomy (PRK) in rabbits, PRK was performed on 60 rabbits. They were randomized to one of four groups: group A which received topical SIMP, group B which received topical CsA, group C which received both SIMP and CsA, and group D which received vehicles. Another 16 rabbits did not undergo PRK and were randomized to one of four groups: group E which received topical SIMP, group F which received topical CsA, group G which received both SIMP and CsA, and group H which received vehicles. SIMP solution (1 mm) was instilled every two hours and 2% cyclosporin was instilled four times a day, this was carried out for as long as 6 weeks after surgery. At one, two, four, and six weeks after surgery, slit lamp examination was performed with haze gradings recorded, and corneal specimens were obtained from groups A, B, C, and D. In groups E-H, all rabbits were killed after six weeks of eyedrops instillation. Light microscopy and immunohistochemistry for collagen types III, IV, and VI were performed on the specimens obtained. Slit lamp examination and light microscopy revealed that SIMP significantly reduced corneal haze after PRK, but CsA did not. Immunohistochemistry revealed that deposition of types III and IV collagen was detected in ablated area in groups A-D, and SIMP reduced the frequency of positive staining for type III collagen. In groups E-F, corneas were normal. These findings suggest that SIMP significantly reduced corneal haze and the synthesis of type III collagen after excimer laser PRK in rabbits.
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Affiliation(s)
- J H Chang
- Department of Ophthalmology, Seoul City Boramae Hospital, Seoul, Korea
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139
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Kwitko ML, Jovkar S, Yan H, Atas M. Radial keratotomy for residual myopia after photorefractive keratectomy. J Cataract Refract Surg 1998; 24:315-9. [PMID: 9559465 DOI: 10.1016/s0886-3350(98)80317-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the safety, efficacy, and complications of radial keratotomy (RK) after photorefractive keratectomy (PRK) for myopia. SETTING Laser Ultravision Institute. Montreal, Canada. METHODS Surgically induced refractive and visual acuity changes were retrospectively evaluated in 14 eyes of 10 patients treated with RK after PRK. All patients had simple myopia or compound myopic astigmatism. Minimum follow-up was 6 months. RESULTS Three eyes (21%) had one PRK, 7 (50%) had two treatments, and 4 (29%) had three. Eleven eyes (79%) required four-incision RK and 3 (21%), eight-incision RK. All patients had improved uncorrected visual acuity. Six months after the RK retreatment, there was a significant reduction in spherical equivalent of 2.93 diopters +/- 1.53 (SD) (P < .05). No intraoperative or postoperative complications occurred except overcorrection (two cases). CONCLUSION Radial keratotomy is an effective, safe method for treating undercorrected myopia after PRK. Further study and analysis of this series of patients are planned.
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Affiliation(s)
- M L Kwitko
- Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
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140
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Higa H, Couper T, Robinson DI, Taylor HR. Multiple Photorefractive Keratectomy Retreatments for Myopia. J Refract Surg 1998; 14:123-8. [PMID: 9574742 DOI: 10.3928/1081-597x-19980301-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To examine the outcome of multiple photorefractive keratectomy retreatments by the excimer laser on eyes treated for myopia and myopic astigmatism. METHODS We present 980 of 1218 (80%) consecutive eyes treated with a VISX 20/20 excimer laser that were available for follow-up. Thirteen eyes of 13 individuals were retreated twice using the same VISX excimer laser because of refractive regression. Epithelium was mechanically removed in the initial treatment and subsequent retreatment of all the eyes. No increased difficulty was noted upon removing the epithelium on subsequent retreatments. The aim in both the initial and subsequent treatments was to correct 100% of the refractive error. RESULTS Eyes with higher amounts of myopia and astigmatism were more likely to require multiple retreatments. Seven eyes (54%) attained a spectacle-corrected visual acuity of 20/20 or better. Twelve eyes (92%) attained a spectacle-corrected visual acuity of 20/40 or greater following the second retreatment. The amount of astigmatism corrected was improved in 10 of the 13 eyes with an average improvement of 1.90 D of cylinder. Only one patient experienced a haze score of 3 or more following retreatment. CONCLUSION There is a subgroup of patients who require multiple PRK retreatments for myopic regression. A good visual outcome may be obtained with minimal haze.
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Affiliation(s)
- H Higa
- Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, University of Melbourne, Victoria, Australia
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141
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Pineda R, Talamo JH. Late Onset of Haze Associated with Viral Keratoconjunctivitis Following Photorefractive Keratectomy. J Refract Surg 1998; 14:147-51. [PMID: 9574746 DOI: 10.3928/1081-597x-19980301-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND To report a newly recognized cause of late onset of corneal haze following photorefractive keratectomy (PRK). METHODS A 35-year old woman who underwent uneventful PRK and subsequently developed viral keratoconjunctivitis 1 year after treatment. RESULTS During resolution of the viral keratoconjunctivitis, the patient developed extensive central corneal subepithelial infiltrates and anterior stromal fibrosis in the PRK ablation zone. More than 1 year after the initial infection, the central subepithelial fibrosis persisted, complicated by myopic regression, central steep island on videokeratography, and loss of five lines of spectacle-corrected visual acuity. By the end of the second year after the infection, visual acuity had improved with disappearance of the central steep island on videokeratography. However, the myopic regression and subepithelial fibrosis remained. CONCLUSION Patients who undergo PRK may be at greater risk of visual loss following viral keratoconjunctivitis secondary to persistent subepithelial infiltrates and/or stromal fibrosis within the PRK treatment zone.
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Affiliation(s)
- R Pineda
- Massachusetts Eye & Ear Infirmary, Boston 02114, USA
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142
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Danjoux JP, Fraenkel G, Wai D, Conway M, Eckstein R, Lawless M. Corneal scarring and irregular astigmatism following refractive surgery in a corneal transplant. ACTA ACUST UNITED AC 1998. [DOI: 10.1111/j.1442-9071.1998.tb01440.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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143
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Abstract
BACKGROUND A new technique, therapeutic alloplastic laser in situ keratomileusis to correct high myopia, is introduced. METHODS Therapeutic alloplastic laser in situ keratomileusis consists of neutral homoplastic epikeratoplasty combined with superficial keratectomy performed with an excimer laser and/or a microkeratome. Indications for the technique are: myopia over 20 diopters (D), eyes with corneal scarring after photorefractive keratectomy (PRK), complications following keratomileusis, radial keratotomy complications with undercorrection, and keratoconus suspect myopic eyes. RESULTS In all five eyes we achieved precise corneal lathing with the microkeratome or the excimer laser, and obtained a clear allograft. In all eyes, we maintained or improved the patient's spectacle-corrected visual acuity related to baseline values. We did not induce astigmatism, and corneal thickness was almost unchanged. CONCLUSIONS Advantages of therapeutic alloplastic laser in situ keratomileusis are that it provides a Bowman's layer for the cornea following keratectomy, it is possible to lathe ablation diameters larger than 5 mm, it prevents the appearance of corneal haze, and reduces the need for corticosteroid treatment.
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Affiliation(s)
- A Maldonado-Bas
- Department of Ophthalmology, National University of Córdoba, Argentina
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144
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Gartry DS, Larkin DF, Hill AR, Ficker LA, Steele AD. Retreatment for significant regression after excimer laser photorefractive keratectomy. A prospective, randomized, masked trial. Ophthalmology 1998; 105:131-41. [PMID: 9442789 DOI: 10.1016/s0161-6420(98)91715-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Regression, a gradual partial or complete return to the myopic state, remains a common complication of excimer laser photorefractive keratectomy (PRK) and limits the predictability of refractive outcome, especially in high myopia. An estimated 10% to 20% of patients, therefore, request a repeat PRK procedure. This study was designed to provide patient selection criteria and guidelines for successful retreatment. METHODS One hundred six patients who had regressed were randomized to 1 of 4 retreatment groups comprising (1) those with minimal haze after their first PRK who received an exact retreatment; (2) those with minimal haze treated with a 50% deliberate overcorrection; (3) those with significant haze (> or = 2+ haze) given an exact retreatment; and (4) those with significant haze who received a 50% overcorrection. A Visx 20/20 laser was used in each case. Mean follow-up after retreatment was 12 months (range, 6-18 months). RESULTS Deliberate overcorrection (groups 2 and 4) resulted in a statistically significantly better refractive outcome (P = 0.026 at 6 months). Analysis of variance showed that significant haze after the first PRK was the most important predictor of a poor outcome after retreatment, other factors being high original myopia, marked regression, and loss of best-corrected visual acuity. CONCLUSIONS A retreatment PRK procedure for significant regression will reduce residual myopia significantly in the majority of patients, and a deliberate overcorrection (50%) reduces the chance of further regression. However, patients with high myopia who have regressed beyond approximately -3.50 diopters originally and who show significant anterior stromal haze (> 2+) should be retreated only with great caution, because of the risk of further regression, haze, and loss of visual acuity.
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Affiliation(s)
- D S Gartry
- Cornea Service, Moorfields Eye Hospital, London, England
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145
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Shah S, Chatterjee A, Doyle SJ, Bessant DA. Epithelial debridement for secondary hyperopia following myopic excimer laser photorefractive keratectomy. J Cataract Refract Surg 1998; 24:31-4. [PMID: 9494896 DOI: 10.1016/s0886-3350(98)80071-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND To evaluate epithelial debridement for the treatment of persistent hyperopia in eyes that had photorefractive keratectomy (PRK). SETTING Optimax Laser Eye Clinics, Manchester, London, Bristol, England. METHODS Epithelial debridement was performed on 46 eyes to reduce the hypermetropia following excimer laser PRK. RESULTS Mean age of the patients was 43 years +/- 9.7 (SD). Mean refractive change was -0.51 diopter (D) +/- 0.76 (range +0.75 to -2.50 D). Mean change in best corrected visual acuity (BCVA) was 0.00 Logmar units (range +0.40 to -0.20 units), although 33% of eyes lost one line or more of Logmar BCVA. Mean follow-up after debridement was 61.0 +/- 26.9 weeks (range 26 to 140 weeks). CONCLUSIONS Epithelial debridement is an unpredictable procedure to treat secondary hyperopia after PRK, producing a small mean change in spherical equivalent with a wide range of results. A significant number of eyes lost one line or more of Logmar BCVA. We therefore do not advocate epithelial debridement after PRK.
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Affiliation(s)
- S Shah
- Optimax Laser Eye Clinic, Manchester, England
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146
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Johnson DG, Kezirian GM, George SP, Casebeer JC, Ashton J. Removal of Corneal Epithelium with Phototherapeutic Technique during Multizone, Multipass Photorefractive Keratectomy. J Refract Surg 1998; 14:38-48. [PMID: 9531084 DOI: 10.3928/1081-597x-19980101-09] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The therapeutic mode of the VISX 20/20 excimer laser was used to remove the corneal epithelium prior to performing photorefractive keratectomy (PRK) with a multizone, multipass technique. METHODS A retrospective analysis was performed of 120 eyes of 90 patients that were treated for preoperative spherical refractive errors from -1.00 to -7.00 diopters (D) (mean -3.90 D, SD 1.54) by one surgeon (DGJ) over 7 months. RESULTS Six-month follow-up was obtained in 76 eyes (63%). Sixty-nine eyes (91%) achieved a spherical equivalent refraction within +/-1.00 D of emmetropia. Regression of effect averaged -0.35 D (SD 0.53 D) from 1 to 6 months after surgery. Mean postoperative uncorrected visual acuity at 6 months was 20/25 (range 20/15 to 20/200). Seventy-three eyes (96%) achieved uncorrected visual acuity of 20/40 or better, 67 (88%) achieved uncorrected visual acuity of 20/25 or better, and 76 (71%) achieved 20/20 or better. Three eyes (4%) lost one line of spectacle-corrected visual acuity; no eye lost more than one line. There were no significant surgical complications. CONCLUSION Removal of corneal epithelium with the Summit Excimed UV 200 LA excimer laser using multizone, multipass photoablation yields visual and refractive results that compare favorably with published PRK series with excellent short-term stability.
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Affiliation(s)
- D G Johnson
- London Place Eye Center, New Westminster, British Columbia, Canada
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Der Intrastromale Corneale Ring (KeraVision® Ring, ICR®, ICRS®) — Eine neue, reversible Methode zur Korrektur der niedrigen Myopie Entwicklung, kritischer Vergleich mit RK und PRK, eigene refraktive Ergebnisse und Nebenwirkungen der ersten 25 Eingriffe. SPEKTRUM DER AUGENHEILKUNDE 1997. [DOI: 10.1007/bf03164200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Baek SH, Chang JH, Choi SY, Kim WJ, Lee JH. The Effect of Topical Corticosteroids on Refractive Outcome and Corneal Haze after Photorefractive Keratectomy. J Refract Surg 1997; 13:644-52. [PMID: 9427202 DOI: 10.3928/1081-597x-19971101-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The effect of topical corticosteroids after excimer laser photorefractive keratectomy (PRK) remains a matter of some controversy. Refractive effects may be different according to the amount of myopia and timing of instillation. METHODS Two groups of patients were studied: Study A consisted of 215 eyes (128 patients) with PRK (mean baseline myopia, -6.53 +/- 2.22 D) that received no corticosteroids (No Corticosteroid Group) unless significant regression or corneal haze appeared (Delayed Corticosteroid Group), and in Study B, we randomly assigned eyes to the Initial Corticosteroid Group (mean baseline myopia, -6.39 +/- 1.84 D) or the No/delayed Corticosteroid Group (mean baseline myopia -5.78 +/- 2.02 D). Clinical results after PRK for low-to-moderate and high myopia were compared. RESULTS In the first group, 70.9% (73 eyes) of moderately myopic eyes (mean, -4.56 +/- 1.10 D) belonged to the No Corticosteroid Group that had a mean refraction of -5.39 +/- 1.77 D. Delayed Corticosteroid Group eyes were more myopic (mean, -7.52 +/- 2.10 D), and showed more severe haze than those in the No Corticosteroid Group. In study B, only in high myopes with more than -6.00 D (mean, -7.76 +/- 1.15 D) did refraction and corneal haze outcomes show significant difference between the Initial Corticosteroid Group and the No/delayed Corticosteroid Group. CONCLUSIONS The effects of topical corticosteroids after PRK were less in moderate myopes compared to high myopes. Delayed instillation of corticosteroids did not reverse the regression or haze whereas initial instillation showed a beneficial effect on high myopes but not on moderate myopes.
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Affiliation(s)
- S H Baek
- Department of Ophthalmology, College of Medicine, Seoul National University, Korea
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Baek SH, Choi SY, Chang JH, Wee WR, Lee JH. Short-term effects of flurbiprofen and diclofenac on refractive outcome and corneal haze after photorefractive keratectomy. J Cataract Refract Surg 1997; 23:1317-23. [PMID: 9423902 DOI: 10.1016/s0886-3350(97)80109-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate the short-term effects of topical nonsteroidal anti-inflammatory drugs (NSAIDs) on refractive outcome and corneal haze after excimer laser photorefractive keratectomy (PRK) according to the degree of myopia and to compare the results with those of topical steroids. SETTING Seoul National University Hospital, Seoul, Korea. METHODS Patients were divided into two groups: low to moderate myopia (-6.00 diopters [D] or less) and high myopia (greater than 6.00 D). Then, each patient was randomly assigned to one of three drug subgroups for initial management (4 months post-PRK): corticosteroids (fluorometholone 0.1%); flurbiprofen sodium 0.03% (Ocufen); diclofenac sodium 0.1% (Decrol). Follow-up was 6 months. RESULTS In eyes with low to moderate myopia, the steroid and diclofenac subgroups had significantly different refractions 2 and 4 months postoperatively but no difference at 6 months; subjective haze grading was consistently lower in the steroid subgroup than in the NSAID subgroups (flurbiprofen, diclofenac) after 2 months. In eyes with high myopia, the steroid subgroup had significantly less myopic regression after 3 weeks and lower subjective haze after 2 months than the NSAID subgroups. The steroid subgroup had severe myopic regression or corneal haze less frequently than the NSAID subgroups. CONCLUSION Topical NSAIDs were less effective than topical steroids in reducing myopic regression and haze after PRK, especially in highly myopic eyes.
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Affiliation(s)
- S H Baek
- Department of Ophthalmology, Seoul National University College of Medicine, Korea
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Kitazawa Y, Tokoro T, Ito S, Ishii Y. The efficacy of cooling on excimer laser photorefractive keratectomy in the rabbit eye. Surv Ophthalmol 1997; 42 Suppl 1:S82-8. [PMID: 9603293 DOI: 10.1016/s0039-6257(97)80030-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We cooled the surface of the cornea to reduce the thermal damage by the excimer laser ablation and referred to this method as "cooling photorefractive keratectomy" (cooling PRK). We performed conventional PRK and cooling PRK on rabbits' eyes and measured the thermal change during laser ablation. We also examined the degree of subepithelial haze and the tissues with a light microscope and an electron microscope. Normal corneal temperature of live rabbit corneas was about 32 degrees C and it rose to 41 degrees C after 300 laser shots. However, when we cooled the rabbit corneas to 24 degrees C with continuous irrigation of chilled BSS PLUS solution before laser ablation, the temperature rose only to 34 degrees C after the same ablation. Slit-lamp evaluation showed that more severe corneal haze occurred with the conventional PRK procedure. At 2 weeks postoperatively, the mean haze score was 1.77 +/- 0.87 in the conventional PRK and 0.87 +/- 0.38 in the cooling PRK (P < 0.01). Light-microscopy examination showed epithelial hyperplasia and fibroblasts, type III collagen, and heat shock protein-70 in the subepithelium of corneas with conventional PRK procedure than with cooling PRK. Under the electron microscope, more disruption of the layers of fibroblasts and collagen fibrils was observed in the conventional PRK procedure than that of the cooling PRK. In conclusion, the cooling of the corneal surface in PRK effectively reduces tissue damage related to subepithelial haze and may enable us to reduce the degree of myopic regression.
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Affiliation(s)
- Y Kitazawa
- Department of Ophthalmology, Tokyo Medical and Dental University, School of Medicine, Japan
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