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Corneal Epithelial Removal with a Newly Designed Epithelial Brush. J Ophthalmol 2021; 2021:4668056. [PMID: 35154818 PMCID: PMC8828349 DOI: 10.1155/2021/4668056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/02/2021] [Indexed: 11/17/2022] Open
Abstract
This study aimed to evaluate and compare the effectiveness of a newly developed epithelial removal brush with conventional methods in a rabbit model of corneal epithelial defects. The corneal epithelia of thirty-seven rabbits were removed by three different methods including blades (blade group), newly developed epithelial brushes (Ocu group), and conventional rotating brushes (Amo group). The defect area was measured with light microscopy immediately and at 4, 18, 24, and 50 hours after removal. Corneas were obtained immediately and at 24 and 50 hours and subjected to hematoxylin and eosin (H&E) and immunofluorescence staining using proliferating cell nuclear antigen (PCNA) and phosphorylated heat shock protein 27 (pHSP27) antibodies. The residual stromal surface was observed by scanning electron microscopy (SEM). In the Ocu group, epithelia were significantly recovered at 18, 24, and 50 hours compared with immediately after removal, and in the blade and Amo groups, epithelia were significantly recovered only at 50 hours after epithelial removal. The expression levels of PCNA and pHSP27 did not differ among three groups. There was significantly more inflammatory cell infiltration in the blade group than in the other groups. SEM showed a more regular and uniform residual stromal surface in the Ocu group than in the other groups. The newly developed epithelial brush showed better polishing ability and led to earlier significant epithelial recovery and a more regular and uniform stromal surface than conventional methods in this rabbit model of epithelial defects. Accumulation of clinical data is expected to expand the scope of application of new brushes for laser surface ablation.
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Charpentier S, Keilani C, Maréchal M, Friang C, De Faria A, Froussart-Maille F, Delbarre M. Corneal haze post photorefractive keratectomy. J Fr Ophtalmol 2021; 44:1425-1438. [PMID: 34538661 DOI: 10.1016/j.jfo.2021.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/21/2021] [Accepted: 05/18/2021] [Indexed: 10/20/2022]
Abstract
Corneal haze represents subepithelial corneal fibrosis, a manifestation of a pathological healing process. It occurs as a result of an epithelial-stromal lesion involving a break in the epithelial barrier. It is an inflammatory response that involves the migration, multiplication and differentiation of keratocytes into mature myofibroblasts, causing loss of corneal transparency. Although it is a transient phenomenon, this complication is feared following refractive photokeratectomy (PRK), because it can cause alterations in the quality of vision, refractive regression and decreased visual acuity. The severity of these symptoms is correlated with the severity of the corneal haze, which can be assessed clinically or by objective means such as corneal densitometry measurement. The frequency and severity of corneal haze increase with the depth of photoablation in PRK and are therefore increased during the treatment of severe ametropia. Considering that no consensus exists, the application of mitomycin C (MMC) intraoperatively and topical corticosteroids postoperatively are conventionally used to inhibit collagen synthesis, sometimes in combination with various protocols depending on the center or surgeon. This review of the literature reports the current knowledge on corneal haze, in order to better understand it and optimise its prevention in the context of a decreased MMC supply, which has occurred in the past and could recur in the future.
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Affiliation(s)
- S Charpentier
- Service d'ophtalmologie, hôpital d'instruction des armées Bégin, 69, avenue de Paris, 94163 Saint-Mandé Cedex, France.
| | - C Keilani
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France
| | - M Maréchal
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - C Friang
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - A De Faria
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - F Froussart-Maille
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France; École du Val-de-Grâce, 1, place Alphonse Laveran, 75230 Paris Cedex 05, France
| | - M Delbarre
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
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Busool Y, Mimouni M, Vainer I, Levartovsky S, Sela T, Munzer G, Kaiserman I. Risk factors predicting steroid-induced ocular hypertension after photorefractive keratectomy. J Cataract Refract Surg 2019; 43:389-393. [PMID: 28410723 DOI: 10.1016/j.jcrs.2016.12.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/21/2016] [Accepted: 12/30/2016] [Indexed: 10/19/2022]
Abstract
PURPOSE To assess the risk factors contributing to steroid-induced ocular hypertension after photorefractive keratectomy (PRK). SETTING Care Laser Centers, Tel Aviv, Israel. DESIGN Retrospective case series. METHODS Patients having PRK between January 2000 and December 2015 were followed for at least 3 months. Intraocular pressure (IOP) was measured using the Goldmann applanation tonometer after 1 week and after 1, 3, and 6 months. Ocular hypertension was defined as an IOP elevation of 25% while on topical steroid treatment (minimum 28 mm Hg) followed by an IOP drop of 25% when steroid treatment was discontinued. RESULTS The study comprised 1783 patients (3566 eyes). The mean age of the patients was 26.95 years ± 7.56 (SD), and 54.85% were men. A total of 106 eyes (2.97%) were steroid responders. The responder group had a higher proportion of men than the nonresponder group (70.75% versus 29.25%; P < .001), higher central corneal thickness (CCT) (531.9 ± 40.2 μm versus 521.2 ± 40.9 μm; P = .008), lower mean keratometry (K) power (43.39 ± 1.84 diopters [D] versus 44.08 ± 1.88 D; P < .001), higher proportion of high myopia (>6.0 D) (31.13% versus 22.18%; P = .03), and higher rate of postoperative corneal haze (16.98% versus 4.25%; P < .001) and were treated postoperatively with more potent steroids. All factors remained significant in the multivariate analysis. CONCLUSION Significant factors associated with post-PRK ocular hypertension were male sex, high CCT, a low mean K reading, high myopia, corneal haze, and treatment with stronger steroids such as dexamethasone.
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Affiliation(s)
- Yumna Busool
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
| | - Michael Mimouni
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel.
| | - Igor Vainer
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
| | - Shmuel Levartovsky
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
| | - Tzahi Sela
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
| | - Gur Munzer
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
| | - Igor Kaiserman
- From the Department of Ophthalmology (Busool, Mimouni, Vaineer), Rambam Health Care Campus, Haifa, the Department of Ophthalmology (Levartovsky, Kaiserman), Barzilai Medical Center, Ashkelon, the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheba, and Care-Vision Laser Centers (Sela, Munzer, Kaiserman), Tel Aviv, Israel
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Singh A, Abd AJ, Al-Mashahedah A, Kanwar JR. Corneal Haze, Refractive Surgery, and Implications for Choroidal Neovascularization. DRUG DELIVERY FOR THE RETINA AND POSTERIOR SEGMENT DISEASE 2018:439-477. [DOI: 10.1007/978-3-319-95807-1_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Dynamic Roles of the Corneal Epithelium in Refractive Surgery. CURRENT OPHTHALMOLOGY REPORTS 2017. [DOI: 10.1007/s40135-017-0149-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Aslanides IM, Kymionis GD. Trans advanced surface laser ablation (TransPRK) outcomes using SmartPulseTechnology. Cont Lens Anterior Eye 2016; 40:42-46. [PMID: 27884617 DOI: 10.1016/j.clae.2016.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate early visual rehabilitation, post-operative pain, epithelial healing and haze after transepithelial photorefractive keratectomy (TransPRK) using the SmartPulseTechnology (SPT) of Schwind Amaris (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany). METHODS This was a retrospective comparative evaluation of a cohort of myopic patients undergoing TransPRK with SPT (group 1), with one matched control group that underwent conventional TransPRK (group 2). All cases had a 6-month post-operative follow-up including visual acuity and slit-lamp examination. Subjective evaluation of pain was recorded post-operatively. RESULTS 49 eyes of 25 patients in group 1 and 40 eyes of 20 patients in group 2 were enrolled. The patients' visual rehabilitation was significantly faster in group 1, one day and one week post-operatively (P<0.05). From one month onward there was no significant difference between the groups. The epithelial defect size was significantly smaller on post-operative days 1 and 2 for group 1 (P<0.05 in both cases). The pain score was also significantly less in group 1 (P<0.05). The haze level had no significant difference between the groups at any post-operative point (P>0.05). DISCUSSION TransPRK using SPT provides promising results in the early post-operative period. Visual rehabilitation, re-epithelialization and pain were faster in the early post-operative period in group 1 in comparison with group 2. Haze formation was not significantly different between the two groups; however, it was consistently less in group 1.
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Affiliation(s)
- Ioannis M Aslanides
- Emmetropia Mediterranean Eye Institute, Plateia Eleftherias 44, Heraklion, Crete 71201, Greece.
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Repeatability of Pentacam peripheral corneal thickness measurements. Cont Lens Anterior Eye 2015; 38:424-9. [DOI: 10.1016/j.clae.2015.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 04/01/2015] [Accepted: 05/13/2015] [Indexed: 11/18/2022]
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Abstract
PURPOSE To provide an overview of the safety and efficacy of mitomycin C (MMC) as adjuvant therapy after refractive surgery procedures. METHODS Literature review. RESULTS Over the past 10 years, MMC has been used by refractive surgeons to prophylactically decrease haze after surface ablation procedures and therapeutically in the treatment of preexisting haze. Development of MMC treatments has had a significant role in the revival of surface ablation techniques. We reviewed the literature regarding mechanism of action of MMC, its role in modulating wound healing after refractive surgery, and its safety and efficacy as adjuvant therapy applied after primary photorefractive keratectomy surgery or after photorefractive keratectomy re-treatment after laser in situ keratomileusis and other corneal surgeries and disorders. The drug is a potent mitotic inhibitor that effectively blocks keratocyte activation, proliferation, and myofibroblast differentiation. Many studies have suggested that MMC is safe and effective in doses used by anterior surface surgeons, although there continue to be concerns regarding long-term safety. After initial depletion of anterior keratocytes, keratocyte density seems to return to normal 6 to 12 months after the use of MMC when corneas are examined with the confocal microscope. Most clinical studies found no difference between preoperative and postoperative corneal endothelial cell densities when MMC 0.02% was applied during refractive surgery, with exposure time of 2 minutes or less. CONCLUSIONS After more than 10 years of use, MMC has been found to be effective when used for prevention and treatment of corneal haze. Questions remain regarding optimal treatment parameters and long-term safety.
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Surface Ablation. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00172-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Moshirfar M, Schliesser JA, Chang JC, Oberg TJ, Mifflin MD, Townley R, Livingston MK, Kurz CJ. Visual outcomes after wavefront-guided photorefractive keratectomy and wavefront-guided laser in situ keratomileusis: Prospective comparison. J Cataract Refract Surg 2010; 36:1336-43. [DOI: 10.1016/j.jcrs.2010.02.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 01/17/2010] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
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Corneal transparency: genesis, maintenance and dysfunction. Brain Res Bull 2009; 81:198-210. [PMID: 19481138 DOI: 10.1016/j.brainresbull.2009.05.019] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 04/14/2009] [Accepted: 05/20/2009] [Indexed: 02/01/2023]
Abstract
Optimal vision is contingent upon transparency of the cornea. Corneal neovascularization, trauma and, surgical procedures such as photorefractive keratectomy and graft rejection after penetrating keratoplasty can lead to corneal opacification. In this article we identify the underlying basis of corneal transparency and factors that compromise the integrity of the cornea. With evidence from work on animal models and clinical studies, we explore the molecular mechanisms of both corneal avascularity and its dysfunction. We also seek to review therapeutic regimens that can safely salvage and restore corneal transparency.
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Corneal Topography Six Years After Photorefractive Keratectomy for Myopia and Myopic Astigmatism. J Refract Surg 2009; 25:451-8. [DOI: 10.3928/1081597x-20090422-08] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Burka JM, Bower KS, VanRoekel RC, Stutzman RD, Kuzmowych CR. The Effect of Moxifloxacin and Gatifloxacin on Long-term Visual Outcomes Following Photorefractive Keratectomy. J Refract Surg 2007; 23:414-7. [PMID: 17455838 DOI: 10.3928/1081-597x-20070401-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the effect of gatifloxacin and moxifloxacin on visual outcomes after photorefractive keratectomy (PRK). METHODS Thirty-five PRK patients were treated postoperatively with gatifloxacin (Zymar) in one eye and moxifloxacin (Vigamox) in the fellow eye. Postoperative regimens were otherwise identical. In a previous study (initial phase), we evaluated epithelial healing. In this study (second phase), we compared uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest spherical equivalent (MSE), and corneal haze at 6 months postoperatively for 32 patients using the Wilcoxon signed ranks test. RESULTS No statistically significant difference was noted between eyes treated with Zymar and Vigamox in terms of UCVA, BSCVA, MSE, or corneal haze at 6 months postoperatively. Two (6%) Vigamox-treated eyes versus 0 (0%) Zymar-treated eyes lost one line of BSCVA from preoperative examination. Median UCVA and MSE were equivalent for both groups. CONCLUSIONS At 6 months after PRK, there was no significant difference in visual outcomes with either antibiotic.
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Affiliation(s)
- Jenna M Burka
- Department of Ophthalmology, Georgetown University/Washington Hospital Center, Washington, DC, USA.
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Lombardo M, Lombardo G, Serrao S. Interocular high-order corneal wavefront aberration symmetry. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2006; 23:777-87. [PMID: 16604757 DOI: 10.1364/josaa.23.000777] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The interocular symmetry of the high-order corneal wavefront aberration (WA) in a population of myopic eyes was analyzed before and after photorefractive keratectomy (PRK). The preoperative and one-year postoperative corneal aberration data (from third to seventh Zernike orders) for 4- and 7-mm pupils from right and left eyes were averaged after correcting for the effects of enantiomorphism to test for mirror symmetry. Also, the mean corneal point-spread function (PSF) for right and left eyes was calculated. Preoperatively, a moderate and high degree of correlation in the high-order corneal WA between eyes was found for 4- and 7-mm pupils, respectively. Myopic PRK did not significantly change the interocular symmetry of corneal high-order aberrations. No discernible differences in the orientation PSF between eyes were observed one year after surgery in comparison with the preoperative state over the two analyzed pupils.
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Affiliation(s)
- Marco Lombardo
- Department of Experimental and Clinical Medicine, University Magna Graecia, Viale Europa, Catanzaro, Italy.
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Netto MV, Mohan RR, Sinha S, Sharma A, Dupps W, Wilson SE. Stromal haze, myofibroblasts, and surface irregularity after PRK. Exp Eye Res 2005; 82:788-97. [PMID: 16303127 PMCID: PMC2693937 DOI: 10.1016/j.exer.2005.09.021] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 09/14/2005] [Accepted: 09/27/2005] [Indexed: 12/25/2022]
Abstract
The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze. Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups: [see table in text]. Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr or 4 weeks after surgery and histochemical analysis was performed on corneas for apoptosis (TUNEL assay), myofibroblast marker alpha-smooth muscle actin (SMA), and integrin alpha4 to delineate the epithelial basement membrane. Slit-lamp grading revealed severe haze formation in corneas in groups IV and VI, with significantly less haze in groups II, III, and VII and insignificant haze compared with the unwounded control in groups I and V. Analysis of SMA staining at 4 weeks after surgery, the approximate peak of haze formation in rabbits, revealed low myofibroblast formation in group I (1.2+/-0.2 cells/400x field) and group V (1.8+/-0.4), with significantly more in groups II (3.5+/-1.8), III (6.8+/-1.6), VII (7.9+/-3.8), IV (12.4+/-4.2) and VI (14.6+/-5.1). The screened groups were significantly different from each other (p < 0.05), with myofibroblast generation increasing with higher surface irregularity in the -4.5 diopter PRK groups. The -9.0 diopter PRK group VI had significantly more myofibroblast generation than the -9.0 diopter PRK with PTK-smoothing group VII (p < 0.01). Areas of basement membrane disruption were demonstrated by staining corneas for integrin alpha4 and were prominent in corneas with grade I or higher haze. SMA-positive myofibroblasts tended to be present sub-adjacent to basement membrane defects. Late apoptosis was detected at 1 month after surgery within clusters of myofibroblasts in the sub-epithelial stroma. In conclusion, these results demonstrated a relationship between the level of corneal haze formation after PRK and the level of stromal surface irregularity. PTK-smoothing with methylcellulose was an effective method to reduce stromal surface irregularity and decreased both haze and associated myofibroblast density. We hypothesize that stromal surface irregularity after PRK for high myopia results in defective basement membrane regeneration and increased epithelium-derived TGFbeta signalling to the stroma that increases myofibroblast generation. Late apoptosis appears to have a role in the disappearance of myofibroblasts and haze over time.
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Affiliation(s)
- Marcelo V. Netto
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
- Department of Ophthalmology, University of São Paulo, Brazil
| | - Rajiv R. Mohan
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sunilima Sinha
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Ajay Sharma
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - William Dupps
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Steven E. Wilson
- The Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
- Corresponding author. Steven E. Wilson, The Cole Eye Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA. E-mail address: (S.E. Wilson)
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Lombardo M, De Santo MP, Lombardo G, Barberi R, Serrao S. Roughness of Excimer Laser Ablated Corneas With and Without Smoothing Measured With Atomic Force Microscopy. J Refract Surg 2005; 21:469-75. [PMID: 16209444 DOI: 10.3928/1081-597x-20050901-08] [Citation(s) in RCA: 14] [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 analyze the surface roughness of porcine corneas after excimer laser ablation with and without the smoothing procedure by means of atomic force microscopy. METHODS Excimer laser photorefractive keratectomy (PRK) was performed on eight porcine corneas. Immediately following the procedure, smoothing was performed on four corneas using a viscous solution of 0.25% sodium hyaluronate. The corneas were examined in balanced salt solution after fixation in 2.5% glutaraldehyde solution using atomic force microscopy. Quantitative analysis of the ablated stromal surface topography was performed using the section analysis module of the atomic force microscopy software. Repeated measurements were made over small areas (< or =50 microm2) near the center of each ablation, with a vertical resolution of <1 nm. RESULTS Images of the ablated stromal surface showed undulations and granule-like features on the ablated surface of the specimens. The specimens on which the smoothing procedure was performed (root-mean-square [RMS] rough: 0.152 +/- 0.014 microm) were more regular (P < .001) than those on which PRK alone was performed (RMS rough: 0.229 +/- 0.018 microm). CONCLUSIONS Atomic force microscopy analysis requires a simpler preparation of the specimens with respect to that necessary for scanning electron microscopy; for this reason, atomic force microscopy techniques are more reliable for the study of biological surfaces and prove to be a feasible method to establish the differences when comparing different laser techniques. Our investigations highlight that although the laser cut of scanning-spot excimer laser systems is precise in removing even the smallest amounts of tissue, the smoothing technique may still be useful to reduce post-ablation roughness.
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Affiliation(s)
- Marco Lombardo
- Department of Experimental and Clinical Medicine, University Magna Greecia of Catanzaro.
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Netto MV, Mohan RR, Ambrósio R, Hutcheon AEK, Zieske JD, Wilson SE. Wound healing in the cornea: a review of refractive surgery complications and new prospects for therapy. Cornea 2005; 24:509-22. [PMID: 15968154 DOI: 10.1097/01.ico.0000151544.23360.17] [Citation(s) in RCA: 279] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE The corneal wound healing response is of particular relevance for refractive surgical procedures since it is a major determinant of efficacy and safety. The purpose of this review is to provide an overview of the healing response in refractive surgery procedures. METHODS Literature review. RESULTS LASIK and PRK are the most common refractive procedures; however, alternative techniques, including LASEK, PRK with mitomycin C, and Epi-LASIK, have been developed in an attempt to overcome common complications. Clinical outcomes and a number of common complications are directly related to the healing process and the unpredictable nature of the associated corneal cellular response. These complications include overcorrection, undercorrection, regression, corneal stroma opacification, and many other side effects that have their roots in the biologic response to surgery. The corneal epithelium, stroma, nerves, inflammatory cells, and lacrimal glands are the main tissues and organs involved in the wound healing response to corneal surgical procedures. Complex cellular interactions mediated by cytokines and growth factors occur among the cells of the cornea, resulting in a highly variable biologic response. Among the best characterized processes are keratocyte apoptosis, keratocyte necrosis, keratocyte proliferation, migration of inflammatory cells, and myofibroblast generation. These cellular interactions are involved in extracellular matrix reorganization, stromal remodeling, wound contraction, and several other responses to surgical injury. CONCLUSIONS A better understanding of the complete cascade of events involved in the corneal wound healing process and anomalies that lead to complications is critical to improve the efficacy and safety of refractive surgical procedures. Recent advances in understanding the biologic and molecular processes that contribute to the healing response bring hope that safe and effective pharmacologic modulators of the corneal wound healing response may soon be developed.
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Affiliation(s)
- Marcelo V Netto
- The Cole Eye Institute, The Cleveland Clinic Foundation, OH 44195, USA
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Serrao S, Lombardo M. Corneal epithelial healing after photorefractive keratectomy: analytical study. J Cataract Refract Surg 2005; 31:930-7. [PMID: 15975458 DOI: 10.1016/j.jcrs.2004.12.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Accepted: 08/27/2004] [Indexed: 10/25/2022]
Abstract
PURPOSE To characterize the velocity of epithelial migration after photorefractive keratectomy (PRK) with 3 different corneal ablation patterns. SETTING Department of Ophthalmology, Catholic University of Rome, Rome, Italy. METHODS Fifteen patients (30 eyes) with mild to moderate myopia and with simple to compound myopic astigmatism were enrolled for this study. The surgical procedure consisted of standardized PRK with final smoothing performed using the Technolas Keracor 217C excimer laser. The reepithelialization process was evaluated at 0 hours, 20 hours, 40 hours, and 60 hours after surgery using a digital photo camera and custom software for measurement. Digital analysis of the images was performed. Corneal topographies were taken at 1 month, 3 months, 6 months, and 12 months after PRK. RESULTS The mean speed of radial migration in the 10 eyes (33%) in the low spherical ablation group was 0.087 mm/h +/- 0.008 (SD). This was significantly higher than that found in the 10 eyes (33%) in the high spherical ablation group (mean speed 0.078 +/- 0.007 mm/h; P<.001) and in the 10 eyes (33%) in the cross-cylinder ablation group (mean speed 0.055 +/- 0.014 mm/h; P<.001). CONCLUSION Analysis of the data shows that epithelial migration along the photoablated corneal surface depends on the ablation pattern. The epithelial sliding is highly influenced by local variations in the curvature of the stromal surface. The data demonstrate that faster epithelial wound healing after PRK is predictive of optimal visual performance.
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Vinciguerra P, Camesasca FI, Torres IM. Transition zone design and smoothing in custom laser-assisted subepithelial keratectomy. J Cataract Refract Surg 2005; 31:39-47. [PMID: 15721695 DOI: 10.1016/j.jcrs.2004.10.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2004] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the results of custom laser-assisted subepithelial keratectomy (LASEK) with a specially designed transition zone and smoothing for the treatment of refractive errors. SETTING Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milan, Italy. METHODS This prospective study involved myopic eyes having refractive surgery with the butterfly LASEK technique and the Nidek EC-5000 excimer laser. The treatment was based on the surgeon's analysis of topographic and aberrometric data provided by Final Fit ablation software, which features the Custom Aspheric Transition Zone software algorithm. After the ablation, smoothing was performed to remove corneal microirregularities. RESULTS Fifty-five eyes of 38 patients were treated. The mean preoperative spherical equivalent (SE) refraction was -6.58 diopters (D) +/- 2.24 (SD) (range -12.13 to -1.75 D). At 1 year, the mean SE refraction was -0.26 +/- 0.79 D (range -4.00 to +0.75 D). CONCLUSION The surface ablation technique provided satisfactory results and took into account strategies to reduce unpredictability factors such as corneal biomechanical forces, haze induced by an irregular postoperative surface, and a high curvature gradient in the transition zone.
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Affiliation(s)
- Paolo Vinciguerra
- Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milan, Italy
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Serrao S, Lombardo G, Lombardo M. Differences in nasal and temporal responses of the cornea after photorefractive keratectomy. J Cataract Refract Surg 2005; 31:30-8. [PMID: 15721694 DOI: 10.1016/j.jcrs.2004.10.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2004] [Indexed: 11/29/2022]
Abstract
PURPOSE To examine the differences in the biomechanical response of the peripheral regions of the cornea after photorefractive keratectomy (PRK). SETTING Department of Ophthalmology, Catholic University of Rome, Rome, Italy. METHODS Preoperative and 1-, 3-, 6-, and 12-month postoperative corneal topographies of 70 eyes that had PRK with the Technolas 217C excimer laser (Bausch & Lomb) were obtained. The eyes were divided into 4 groups according to the preoperative spherical equivalent refraction. Preoperative and follow-up topographic data were imported into custom software that computed the average composite corneal map and difference maps in each group to scientifically evaluate the corneal response to the surgery. The software was also used to analyze regional corneal changes after the laser ablation. Corneal peripheries up to 9.0 mm were evaluated. RESULTS The preoperative corneas had a flatter nasal periphery than temporal periphery. The corneal surfaces in the right eyes and left eyes showed a mirror symmetry. Significant differences in the regional response of the cornea were observed (P<.05), with a greater increase in the curvature of the nasal periphery than in the temporal periphery. CONCLUSIONS To refine modeling of the cornea, the different regional anatomic features and biomechanical responses must be considered. Modifying existing ablation algorithms to compensate for the differences between nasal and temporal corneal flattening of the preoperative corneal surface and between the nasal and temporal responses may improve the postoperative corneal shape and quality of peripheral optics.
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Affiliation(s)
- Sebastiano Serrao
- Department of Ophthalmology, Catholic University of Rome, Rome, Italy.
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Serrao S, Lombardo M. One-year Results of Photorefractive Keratectomy With and Without Surface Smoothing Using the Technolas 217C Laser. J Refract Surg 2004; 20:444-9. [PMID: 15523955 DOI: 10.3928/1081-597x-20040901-06] [Citation(s) in RCA: 13] [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 assess the efficacy, predictability, stability, and safety of a smoothing technique in patients with myopia immediately after photorefractive keratectomy (PRK) using a scanning-spot excimer laser. METHODS Using the Technolas 217C excimer laser, PRK was performed on 100 eyes of 54 patients. Ablation zone diameter was 6.0 mm and transition zone diameter was 9.0 mm. The eyes were randomized into two groups: in 50 eyes PRK alone was performed and in the other 50 eyes, a smoothing technique was performed after the initial ablation. Preoperative mean spherical equivalent refraction was -4.98 +/- 1.71 D in the PRK only group (range -2.25 to -8.60 D) and -4.82 +/- 1.61 D in the smoothing group (range -2.00 to -8.00 D). Follow-up was 12 months for all patients. RESULTS At 1 year after surgery, mean manifest spherical equivalent refraction was -0.61 +/- 0.50 D (range -2.25 to +0.62 D) in the PRK only group and in the smoothing group, +0.02 +/- 0.32 D (range -0.75 to +0.75 D). Postoperative regularity topographic indices were lower in the smoothing group than in the PRK group (P<.001). CONCLUSIONS Smoothing after PRK for correction of myopia up to -6.50 D increased surface regularity, as expressed by lower topography surface regularity indices, and reduced the incidence and severity of postoperative haze. We observed higher predictability throughout follow-up in the smoothing group, which may be addressed by a nomogram adjustment in the PRK only group.
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Affiliation(s)
- Sebastiano Serrao
- Catholic University of Rome, Department of Ophthalmology, Rome, Italy.
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Lombardo M, Serrao S. Smoothing of the Ablated Porcine Anterior Corneal Surface Using the Technolas Keracor 217C and Nidek EC-5000 Excimer Lasers. J Refract Surg 2004; 20:450-3. [PMID: 15523956 DOI: 10.3928/1081-597x-20040901-07] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To demonstrate efficacy of a smoothing technique to increase regularity of the anterior corneal surface after photorefractive keratectomy (PRK), using two different excimer lasers. METHODS Spherical ablations of -10.00 D were performed on 11 fresh porcine corneas using either the Technolas Keracor 217C scanning-spot or the Nidek EC-5000 scanning-slit beam excimer laser. Following the procedure, we performed a phototherapeutic keratectomy treatment (smoothing technique) on half of the corneal surface. The smoothing technique was performed using a viscous solution of 0.25% sodium hyaluronate, which was spread on the cornea prior to the procedure. The ablation zone was 6 mm in diameter and the transition zone extended to 3 mm. The ablation depth was set at 10 microm. Corneas were then examined with scanning electron microscopy. RESULTS Smoother treatment zones were apparent in porcine corneas in which smoothing was performed following PRK, with both laser systems. Results from the two lasers were not directly compared. CONCLUSIONS The smoothing procedure performed following PRK using a viscous 0.25% sodium hyaluronate masking solution and a scanning laser system rendered the porcine corneal surface more regular.
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Affiliation(s)
- Marco Lombardo
- Catholic University of Rome, Department of Ophthalmology, Rome, Italy.
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