Photorefractive keratectomy for residual myopia after radial keratotomy. PRK After RK Study Group

Laser vision correction after radial keratotomy: systematic review and meta-analysis

Laser vision correction for residual refractive errors in patients with previous radial keratotomy (RK) presents a challenging task. Different techniques have been used with varying outcomes. This study aimed to systematically review published articles on refractive surgeries in post-RK patients by conducting a search on PubMed, Scopus, and Web of Science. The final analysis included 35 studies that described a total of 888 eyes. Our systematic review and meta-analysis demonstrated a significant improvement in uncorrected distance visual acuity (UDVA) for photorefractive keratectomy (PRK), topography-guided PRK, wavefront-guided PRK, and femtosecond laser-assisted in situ keratomileusis (LASIK) while mechanical microkeratome LASIK did not yield such significant improvements. Moreover, our results suggest that post-RK patients with hyperopia had a significant improvement in UDVA, whereas no such improvement was observed in patients with myopia.

BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report provides an overview of the evidence for the treatment profile, safety, and efficacy of the range of corneal techniques currently available for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. Presbyopia correction by conductive keratoplasty involves application of radiofrequency energy to the mid-peripheral corneal stroma which leads to mid-peripheral corneal shrinkage, inducing central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Understanding cornea epithelial stem cells and stem cell deficiency: Lessons learned using vertebrate model systems

Animal models have contributed greatly to our understanding of human diseases. Here, we focus on cornea epithelial stem cell (CESC) deficiency (commonly called limbal stem cell deficiency, LSCD). Corneal development, homeostasis and wound healing are supported by specific stem cells, that include the CESCs. Damage to or loss of these cells results in blindness and other debilitating ocular conditions. Here we describe the contributions from several vertebrate models toward understanding CESCs and LSCD treatments. These include both mammalian models, as well as two aquatic models, Zebrafish and the amphibian, Xenopus. Pioneering developments have been made using stem cell transplants to restore normal vision in patients with LSCD, but questions still remain about the basic biology of CESCs, including their precise cell lineages and behavior in the cornea. We describe various cell lineage tracing studies to follow their patterns of division, and the fates of their progeny during development, homeostasis, and wound healing. In addition, we present some preliminary results using the Xenopus model system. Ultimately, a more thorough understanding of these cornea cells will advance our knowledge of stem cell biology and lead to better cornea disease therapeutics.

Multifocal Intraocular Lens Results in Correcting Presbyopia in Eyes After Radial Keratotomy

OBJECTIVES

To report results of multifocal intraocular lens (IOL) implantation in 2 patients with refractive error and presbyopia after previous radial keratotomy (RK).

METHODS

A refractive multifocal IOL with rotational asymmetry (LS313-MF30; Oculentis, Berlin, Germany) was implanted.

RESULTS

The first patient was a 60-year-old man with myopia who underwent unilateral RK 20 years before. His uncorrected distance visual acuity (UDVA) was 20/400, and his distance corrected near vision was J9 in both eyes. Six months after bilateral surgery, his binocular UDVA and uncorrected near visual acuity (UNVA) improved to 20/20 and J1, respectively, although he experienced diurnal fluctuation. The second patient was a 55-year-old woman with hyperopia who underwent bilateral RK 18 years before. Uncorrected distance visual acuity was 20/25 in both eyes, but UNVA was between J9 and J10. Three months after unilateral surgery, UDVA and UNVA of the postsurgical eye improved to 20/20 and J1, respectively. Neither patient reported any significant photic phenomena, and both were satisfied with the results of treatment.

CONCLUSIONS

The desirable clinical outcomes and levels of satisfaction expressed by these patients indicate that surgery using this particular multifocal IOL may benefit presbyopic patients with previous RK.

Laser in-situ keratomileusis for refractive error following radial keratotomy

AIM

To evaluate the safety and efficacy of laser in-situ keratomileusis (LASIK) in eyes with residual/induced refractive error following radial keratotomy (RK).

DESIGN

Retrospective study.

MATERIALS AND METHODS

A retrospective analysis of data of 18 eyes of 10 patients, who had undergone LASIK for refractive error following RK, was performed. All the patients had undergone RK in both eyes at least one year before LASIK. Parameters like uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), contrast sensitivity, glare acuity and corneal parameters were evaluated both preoperatively and postoperatively. STATISTICAL SOFTWARE: STATA-9.0.

RESULTS

The mean UCVA before LASIK was 0.16±0.16 which improved to 0.64 ± 0.22 ( P < 0.001) after one year following LASIK. Fourteen eyes (out of 18) had UCVA of ≥ 20/30 on Snellen's acuity chart at one year following LASIK. The mean BCVA before LASIK was 0.75 ± 0.18. This improved to 0.87 ± 0.16 at one year following LASIK. The mean spherical refractive error at the time of LASIK and at one year after the procedure was -5.37 ± 4.83 diopters (D) and -0.22 ± 1.45D, respectively. Only three eyes had a residual spherical refractive error of ≥ 1.0D at one year follow-up. In two eyes, we noted opening up of the RK incisions. No eye developed epithelial in-growth till 1 year after LASIK.

CONCLUSION

LASIK is effective in treating refractive error following RK. However, it carries the risk of flap-related complications like opening up of the previously placed RK incisions and splitting of the corneal flap.

LASIK surgery in patients with residual refractive errors after radial keratotomy

AIM

To study the results and complications of LASIK surgery after radial keratotomy.

METHODS

This descriptive study was carried out in Yazd LASIK Center, Yazd, Iran. Cases included all patients who had been operated between April 2003 and September 2006. Data were collected via a special questionnaire and analyzed by SPSS software and paired t-test.

RESULTS

Samples included 33 eyes of 23 patients of whom 11 (47.8%) were women and 12 (52.2%) were men. Their age ranged from 28 to 49 years old and the mean age was 31.6 years old. Two cases (6.1%) had openings of the previous radial keratotomy incisions during flap lifting and one case (3%) had moderate non-infectious keratitis. The mean preoperative spherical equivalent (SE) was -2.17D±0.94SD, while the postoperative SE was -0.17D±0.19SD, the difference of which was significant (P=0.0001). Mean preoperative uncorrected visual acuity (UCVA) was 0.07±0.02SD (logMAR) and the postoperative was 0.880.16SD (log MAR), the difference of which was also significant (P=0.0001). The mean best spectacle corrected visual acuity prior to the operation was 0.930.08SD (log MAR) and 0.920.08SD (logMAR) after the operation, the difference of which was not significant (P=0.268).

CONCLUSION

LASIK surgery could improve residual myopia after the radial keratotomy without major complications during or post operation, but necessity of the second procedure must be pondering and require careful case selection and assessment.

Mitomycin C in corneal refractive surgery

Mitomycin C has played a deciding role in the current revival of excimer laser surface ablation techniques. We review the literature regarding mechanism of action of mitomycin C, histological effects on the cornea, and indications, dose, exposure time, and toxicity of mitomycin C in corneal refractive surgery. Mitomycin C is an alkylating agent with cytotoxic and antiproliferative effects that reduces the myofibroblast repopulation after laser surface ablation and, therefore, reduces the risk of postoperative corneal haze. It is used prophylactically to avoid haze after primary surface ablation and therapeutically to treat pre-existing haze. There is no definite evidence that establishes an exact diopter limit or ablation depth at which to apply prophylactic mitomycin C. It is usually applied at a concentration of 0.2mg/ml (0.02%) for 12 to 120 seconds over the ablated stroma, although some studies suggest that lower concentrations (0.01%, 0.002%) could also be effective in preventing haze when treating low to moderate myopia. This dose of mitomycin C has not been associated with any clinically relevant epithelial corneal toxicity. Its effect on the endothelium is more controversial: two studies report a decrease in endothelial cell density, but the majority of reports suggest that the endothelium is not altered. Regarding mitomycin C's effect on keratocyte population, although animal studies report keratocyte depletion after its use, longer follow-up suggested that the initial keratocyte depletion does not persist over time.

Wavefront-guided photorefractive keratectomy in eyes with prior radial keratotomy: a multicenter study

PURPOSE

To investigate the outcomes of wavefront-guided photorefractive keratectomy (WG PRK) using prophylactic mitomycin C (MMC) in eyes that had previously undergone radial keratotomy (RK).

DESIGN

Retrospective, observational, consecutive case series.

PARTICIPANTS

Thirty-two eyes of 27 patients with previous RK that underwent WG PRK with MMC.

METHODS

The records were reviewed of consecutive RK patients whose eyes underwent WG PRK with MMC in 4 centers with postoperative follow-up of 6 months or longer (range, 6-21 months). Eyes were divided into myopic WG PRK and hyperopic WG PRK groups based on their preoperative spherical equivalent (SE). Preoperative best spectacle-corrected visual acuity (BSCVA) was compared with postoperative uncorrected visual acuity (UCVA) and BSCVA to ascertain efficacy and safety. Change in SE and attempted versus achieved SE were evaluated. Incidences of haze and other complications were recorded.

MAIN OUTCOME MEASURES

Uncorrected visual acuity, BSCVA, SE, corneal haze, and other complications.

RESULTS

In the myopic WG PRK group (n = 9), UCVA improved by 3 lines on average (P = 0.015) with UCVA of > or =20/20 in 56% and > or =20/40 in 100% of eyes; 55% were within 0.5 diopter (D), and 100% were within 1 D of attempted refraction. In the hyperopic WG PRK group (n = 23), UCVA improved for 3 lines on average (P<0.001), with UCVA of > or =20/20 in 48% and > or =20/40 in 100% of eyes; 57% were within 0.5 D and 74% were within 1 D of attempted refraction. One eye lost 2 lines of BSCVA as a result of the development of mild to moderate haze, but recovered in 4 months. No eyes lost more than 2 lines of BSCVA. Six eyes (19%; 6/32) experienced the development of haze in the postoperative course, with mild to moderate haze in 1 eye and trace haze in the other 5 eyes. No other complications were noted.

CONCLUSIONS

Wavefront-guided PRK with MMC in eyes with prior RK improved the UCVA significantly and was safe over the short follow-up of this series. Although haze occurred, no eye suffered persistent visual loss of 2 or more lines.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Complicated Flap Creation With Femtosecond Laser After Radial Keratotomy

PURPOSE

To report a case of laser in situ keratomileusis (LASIK) that used the Intralase femtosecond laser 14 years after radial keratotomy (RK) for residual myopic astigmatism.

METHODS

A 39 year-old male patient had undergone a bilateral RK operation for myopic correction. The manifest refraction was -1.25 -3.00 x 175 D, with uncorrected visual acuity (UCVA) of 20/50 and best-corrected visual acuity (BCVA) of 20/20. The central and thinnest pachymetry measurements were 582 and 576 mum, respectively, by Orbscan II.

RESULTS

Intralase was used for LASIK, and initially, a loss of suction was seen during flap formation. The flap could be created again at the same intracorneal plane. During flap lifting, the RK incisions were separated, and one of the RK incisions progressed to the corneal center with the force applied by the blunt spatula. No piece was separated completely from the flap. Excimer laser treatment and flap repositioning could be done without any problems. At the fifth postoperative month, his UCVA was 20/20. All RK incisions seemed well aligned. There was no haze or epithelial ingrowth.

CONCLUSIONS

This case showed that the Intralase femtosecond laser not only has no unique benefit as opposed to the mechanical keratome for post-RK eyes but also can lead to serious complications. We recommend that femtosecond laser flap formation not be used in post-RK eyes.

Artisan iris-fixated toric phakic and aphakic intraocular lens implantation for the correction of astigmatic refractive error after radial keratotomy

We report 2 patients who had radial keratotomy (RK) to correct myopia. The first patient developed a postoperative hyperopic shift and cataract. Nine years post RK, she had intracapsular cataract extraction and implantation of an Artisan aphakic intraocular lens (IOL). Twenty years post RK, hyperopia and astigmatism progressed to +7.0 -5.75 x 100 with a best corrected visual acuity (BCVA) of 20/20. Due to contact lens intolerance, the Artisan aphakic IOL was exchanged for an Artisan toric aphakic IOL. Three months later, the BCVA was 20/20 with +1.0 -0.50 x 130. The second patient demonstrated residual myopic astigmatism 6 years after bilateral RK and had become contact-lens intolerant. An Artisan toric phakic IOL was implanted in both eyes. Four months later, the BCVA was 20/25 with a refraction of +0.25 -1.0 x 135 and 20/20 with a refraction of -1.0 x 40. Both patients were satisfied with the visual outcomes.

Prophylactic Mitomycin C to Inhibit Corneal Haze After Photorefractive Keratectomy for Residual Myopia Following Radial Keratotomy

PURPOSE

To evaluate the efficacy and safety of mitomycin C (MMC) 0.02% in inhibiting haze formation after excimer laser photorefractive keratectomy (PRK) for residual myopia following radial keratotomy (RK).

METHODS

A prospective, nonrandomized, noncomparative interventional case series was conducted of 22 eyes (14 patients) with residual myopia after RK performed at a single institution. All eyes were treated with PRK and a single intraoperative topical application of MMC 0.02% solution for 2 minutes using a soaked cellulose sponge placed over the ablated area. Refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and slit-lamp evidence of cotneal opacity (haze) were evaluated over 12 months.

RESULTS

Twelve months postoperatively, 3 eyes showed grade 1 haze, and 2 eyes showed grade 0.5 haze. Twelve months postoperatively, 2 (9%) eyes had UCVA > or = 20/20. No eye before and 17 (77%) eyes after treatment had UCVA > or = 20/40, and no eye before and 9 eyes (40.9%) after treatment had UCVA > or = 20/25. Best spectacle-corrected visual acuity was > or = 20/40 in all (100%) eyes and 21 (95%) eyes before and after treatment, respectively, and > or = 20/25 in 12 (54.5%) eyes before and after treatment. One (4.5%) eye lost 1 line of BSCVA. Mean spherical equivalent refraction achieved was -0.18 diopters (D) (range: -0.75 to +0.50 D) compared to -2.72 D (range: -1.50 to -4.00 D) before treatment. Twelve months after treatment, 19 (85.5%) eyes had a refractive outcome within +/- 0.50 D.

CONCLUSIONS

A single intraoperative application of MMC 0.02% for 2 minutes appears to be effective in preventing subepithelial haze after PRK for residual myopia in patients with undercorrection or regression following RK.

Hyperopic laser in situ keratomileusis in eyes with previous radial keratotomy

PURPOSE

To assess the safety and efficacy of hyperopic laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK).

SETTING

Zale Lipshy University Hospital Laser Center for Vision, University of Texas Southwestern Medical Center, Dallas, Texas, USA.

METHODS

Thirty-eight eyes of 25 patients were treated with LASIK for secondary hyperopia after RK using a Visx Star S2, S3, S4, or LADARVision excimer laser. Retreatment was done in 7 eyes. The main outcome measures were manifest refraction spherical equivalent (MRSE), uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), predictability of treatment, and complications.

RESULTS

Preoperative mean MRSE was +2.39 diopters (D) +/- 1.28 (SD) (range +0.87 to +6.00 D). At the last visit (25 eyes with minimum follow-up of 12 months, including retreatments), the mean follow-up was 23.3 +/- 7.3 months (range 12 to 34 months), the mean MRSE was +0.11 +/- 0.71 D, and the UCVA was 20/40 or better in 24 eyes (96%). Although no significant change in the mean MRSE was observed, the postoperative mean refractive cylinder showed a gradual increase over the follow-up period. No eye lost more than 2 lines of BSCVA.

CONCLUSIONS

Laser in situ keratomileusis was a safe and effective treatment with good predictability for the correction of consecutive hyperopia after RK. Cylindrical errors were difficult to correct, and astigmatic correction tended to regress over time. Retreatments are safe when old flaps were relifted.

Long Term Analysis of LASIK for the Correction of Refractive Errors After Penetrating Keratoplasty

PURPOSE

To determine the long-term safety and effectiveness of laser in-situ keratomileusis (LASIK) in the treatment of refractive errors following penetrating keratoplasty (PK).

METHODS

A retrospective review was performed of 57 eyes of 48 patients with anisometropia or high astigmatism who were unable to wear glasses or a contact lens after PK and who underwent LASIK for visual rehabilitation. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), and corneal transplant integrity were recorded before surgery as well as up to 60 months after LASIK.

RESULTS

The mean follow-up after the LASIK was 21.4 +/- 14.2 months (range 3 to 60 months). Mean preoperative spherical equivalent (SE) was -4.19 +/- 3.38 D. The mean preoperative astigmatism was 4.67 +/- 2.18 D. Preoperative BCVA was 20/40 or better in 42 eyes (74%). At 2 years the mean SE was -0.61 +/- 1.81 D, and mean astigmatism was 1.94 +/- 1.35 D for the 28 eyes with follow-up. UCVA was 20/40 or better in 12 eyes (43%), and BCVA was 20/40 or better in 24 eyes (86%) at 2 years. A gain in BCVA of 1 line or more was seen in 8 eyes (29%). Two eyes (7%) had loss of 2 or more lines of BCVA at 2 years. There were 9 eyes (16%) that developed epithelial ingrowth. Five eyes (9%) in this series had repeat corneal transplants.

CONCLUSIONS

LASIK is effective for reducing ametropia after PK. Proper patient counseling is necessary because the results of LASIK after PK are not as good as, and complications are more frequent than in eyes with naturally occurring myopia and astigmatism. Complications are especially common in patients with mismatch of the donor and host cornea or in those with poor endothelial cell function.

Central Corneal Haze Increased by Radial Keratotomy Following Photorefractive Keratectomy

PURPOSE

To report a case of central corneal haze induced by minimally invasive radial keratotomy (mini-RK) after photorefractive keratectomy (PRK) and subsequent deep lamellar keratoplasty.

METHODS

We report a case (one eye of one patient) of central corneal haze that worsened after mini-RK was performed 2 years following PRK. Four years later, a second PRK was done, myopic regression was subsequently observed, and corneal haze persisted. Deep lamellar keratoplasty was performed and a corneal graft was taken, which was examined by light and electron microscopy.

RESULTS

In the ablated area, irregularity of the basal membrane and hypertrophy of the corneal epithelium were observed. In the stromal layer, collagen fibers showed disorder in their disposition. Aggregated activated keratocytes were observed. An epithelial plug filling the gap of the RK incision persisted for 6 years after the mini-RK. The RK incision was easily divided when deep lamellar keratoplasty was performed and the patient obtained a stable visual outcome.

CONCLUSIONS

It is possible that mini-RK enhancement after PRK induces central corneal haze and reduces corneal integrity. Deep lamellar keratoplasty for refractory corneal haze after refractive surgery was useful in this eye.

Photorefractive keratectomy to correct hyperopic shift after radial keratotomy

To evaluate the safety, efficacy, and predictability of photorefractive keratectomy (PRK) to correct post-radial-keratotomy (RK) hyperopic shift. University of Sherbrooke, Sherbrooke, Québec, Canada.This retrospective nonconsecutive case series comprised 53 eyes of 53 patients who had PRK to correct hyperopic shift after RK. Both RK and PRK were performed by the same surgeon at the same clinic from 1993 to 2001.The mean time after RK was 57 months (range 24 to 84 months). The mean follow-up after hyperopic PRK (HPRK) was 10 months (range 3 to 33 months). The mean hyperopic shift 1 month post-RK to HPRK was +1.6 diopters (D) +/- 1.0 (SD) (range +0.25 to +4.125 D). The mean pre-HPRK spherical equivalent (SE) was +2.15 +/- 0.80 D (range +1.00 to +4.125 D) and the mean post-HPRK SE, -0.10 +/- 0.80 D (range -2.00 to +2.125 D). At the last examination, 47 eyes (88.7%) had a refractive error within +/-1.0 D of emmetropia and 38 eyes (71.7%) had an uncorrected visual acuity of 20/25 or better. Two eyes lost 1 Snellen line of best corrected visual acuity. No significant haze or complications developed in any eye. Hyperopic PRK with a conservative technique (large optical zone and small ablation thickness) can be used successfully to correct RK-induced hyperopia in patients with small to moderate refractive errors. It appeared to be effective, predictable, and safe.

Surgically induced topographical abnormalities after LASIK: management of central islands, corneal ectasia, decentration, and irregular astigmatism

Proper preoperative evaluation is critical for avoiding many postoperative complications associated with laser in-situ keratomileusis (LASIK). Proper nonsurgical management includes careful monitoring of patients during the recovery period using various testing procedures, including corneal topography. When surgical intervention is required, a stepwise approach often is used as a conservative treatment, allowing further treatment if necessary. Many complications after LASIK are amenable to further treatment. However, it often is advisable to monitor patients until improved instrumentation is developed. The authors review the etiology and management of several complications after LASIK by reviewing the literature and relaying their own clinical experiences.

Laser in situ keratomileusis for residual myopia after radial keratotomy and photorefractive keratectomy

PURPOSE

To evaluate the visual outcome, stability, and complications of laser in situ keratomileusis (LASIK) for residual myopia after radial keratotomy (RK) and photorefractive keratectomy (PRK).

SETTING

Dr. Agarwal's Eye Hospital, Chennai, India.

METHODS

Twenty eyes that had LASIK treatment for residual myopia after RK (10 eyes) or PRK (10 eyes) were retrospectively analyzed. Laser in situ keratomileusis was performed after a mean period of 24.3 months +/- 0.75 (SD) in the RK group and 22.0 +/- 1.07 months in the PRK group.

RESULTS

At the last follow-up, the mean spherical equivalent was reduced from -6.05 +/- 1.98 diopters (D) to -1.26 +/- 0.32 D (P <.05) in the RK group and from -3.38 +/- 1.30 D to -0.55 +/- 0.40 D (P <.005) in the PRK group. The mean uncorrected visual acuity improved from 20/300 (range 20/600 to 20/200) to 20/40 (range 20/60 to 20/20) (P <.05) and from 20/200 (range 20/800 to 20/80) to 20/25 (range 20/40 to 20/20) (P <.05), respectively. Two eyes in the RK group and 3 in the PRK group gained 1 line of best corrected visual acuity, and 2 eyes in the RK group lost 1 line. No sight-threatening complications such as a free flap, corneal ectasia, or a retinal complication occurred. There was no statistically significant difference in corneal haze before and after LASIK. Two eyes in the RK group required repositioning of the flap because of irregular apposition to the stromal bed.

CONCLUSION

Laser in situ keratomileusis was safe, effective, and stable in the treatment of residual myopia after RK and PRK.

Laser in situ keratomileusis for undercorrection and overcorrection after radial keratotomy

PURPOSE

To evaluate laser in situ keratomileusis (LASIK) in the management of overcorrection and undercorrection after radial keratotomy (RK).

SETTING

Instituto Oftalmológico de Alicante, Alicante, Spain.

METHODS

This prospective study comprised 20 eyes of 13 patients. The eyes were divided into 2 groups: 11 eyes that were overcorrected after RK and 9 eyes that were undercorrected after RK. Both groups were treated with LASIK after a mean interval of 22 months +/- 8.4 (SD) (range 12 to 45 months). The follow-up was 6 months.

RESULTS

Six months after LASIK, there was a significant decrease in the spherical equivalent in both groups. Ninety-one percent of eyes in the overcorrected group and 89% in the undercorrected group were within +/-1.0 diopter of the intended correction. There was a significant improvement in the uncorrected visual acuity in both groups. In the overcorrected group, 91% showed no change or improvement in their best corrected visual acuity; in the undercorrected group, 89% showed no change or improvement.

CONCLUSIONS

Laser in situ keratomileusis was relatively safe in treating both overcorrection and undercorrection after RK. With proper intraoperative precautions, LASIK can effectively treat the residual refractive defects after RK.

Laser in situ keratomileusis to correct residual myopia and astigmatism after radial keratotomy

PURPOSE

To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) in selected post-radial-keratotomy (RK) eyes with residual myopia and astigmatism.

SETTING

TLC-The Brea Laser Eye Center, Brea, California, USA.

METHODS

Nine eyes of 6 patients who had had RK but had residual myopia and/or astigmatism had LASIK. All RK eyes had 8 radial incisions, were more than 1 year post-RK, had no epithelial inclusion cysts or corneal disease, and had had no subsequent ocular surgery. Follow-up was a minimum of 13 months, at which time uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, cycloplegic refraction, keratometry, central and peripheral pachymetries, intraocular pressure, and a subjective assessment of visual function were obtained.

RESULTS

At the last follow-up, the mean spherical equivalent (SE) was -0.156 diopter (D) +/- 0.174 (SD). All eyes treated for distance vision had a UCVA of 20/25 or better. No patient lost BCVA. No intraoperative or postoperative complications occurred. Seven eyes had morning and evening measurements. The mean change in manifest SE from morning to evening was -0.143 D. Six of the 7 eyes (86%) had 0 to 1 Snellen line change in UCVA from morning to evening. The subjective questionnaire revealed a high degree of satisfaction with overall vision, minimal glare, and less fluctuation in daily vision than before LASIK.

CONCLUSION

Laser in situ keratomileusis is safe and efficacious for reducing residual myopia and astigmatism in properly selected RK patients.