Laser in situ Keratomileusis Enhancement After Radial Keratotomy

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.

Pinhole pupilloplasty after previous radial keratotomy

The multiple radial stromal deep corneal incisions placed in radial keratotomy (RK) lead to higher-order aberrations and pose a surgical challenge to performing any further corrective procedure on the cornea because of fear of inducing an incisional dehiscence. A method to perform pinhole pupilloplasty (PPP) in the setting of previous RK is presented. Application of pinhole optics by performing PPP leads to significant improvement in image quality and helps to optimize visual potential in post-RK cases.

One-Year Outcomes of Femtosecond Laser-Assisted LASIK Following Previous Radial Keratotomy

PURPOSE

To report the 1-year outcomes of LASIK in patients with previous radial keratotomy using a novel femtosecond laser platform.

METHODS

The charts of 27 eyes of 18 patients who underwent femtosecond laser-assisted LASIK with the WaveLight FS200 laser (Alcon Laboratories, Inc., Fort Worth, TX) for consecutive hyperopia following previous radial keratotomy were retrospectively reviewed at a single private practice location. The preoperative characteristics, intraoperative details, and postoperative results were evaluated.

RESULTS

All 27 eyes had successful femtosecond laser flap creation without significant intraoperative or postoperative complications. Uncorrected visual acuity significantly improved postoperatively to 0.13 ± 0.13 logMAR at 12 months of follow-up (P < .0001). Postoperative spherical equivalent averaged 0.11 ± 0.53 diopters. None of the patients lost any lines of corrected distance visual acuity during the postoperative period.

CONCLUSIONS

The femtosecond laser technique described by this study resulted in a safe and effective way to deliver LASIK following previous radial keratotomy. Future investigations are needed to further validate the outcomes of this study.

Femtosecond Laser Flap Creation for Laser In Situ Keratomileusis in the Setting of Previous Radial Keratotomy

PURPOSE

The aim of the study was to report the outcomes of laser in situ keratomileusis (LASIK) in subjects with previous radial keratotomy (RK) using a novel femtosecond laser setting on a proprietary femtosecond laser platform.

DESIGN

This was a retrospective, consecutive chart review of patients at a single private practice institution.

METHODS

The medical records of 16 eyes of 8 subjects who underwent femtosecond-assisted LASIK for consecutive hyperopia after RK were retrospectively reviewed. The preoperative characteristics, intraoperative details, and postoperative outcomes were analyzed.

RESULTS

All 16 eyes had successful femtosecond laser flap creation without significant intraoperative or postoperative complications. Uncorrected visual acuity significantly improved postoperatively (P = 0.0142) and remained stable through the final follow-up interval at 9 to 12 months postoperatively. None of the subjects lost any lines of best spectacle-corrected visual acuity in the postoperative period.

CONCLUSIONS

The novel femtosecond laser technique described in this study can provide a safe and effective method for patients undergoing LASIK after previous RK. Future investigations are required to further validate the findings reported in this study.

Corneal Suture for the Correction of Hyperopia Following Radial Keratotomy

PURPOSE

To report the visual and refractive changes observed after double concentric corneal suture to correct hyperopic shift after radial keratotomy (RK).

METHODS

This retrospective consecutive case series comprised 17 eyes (15 patients) that underwent two concentric corneal sutures (modified Grene Lasso suture) to correct hyperopic shift after RK. All surgeries were performed by the same surgeon between 2000 and 2003.

RESULTS

The mean time after RK was 11.6 +/- 3.2 years. The mean follow-up was 20.3 +/- 11.3 months. The spherical equivalent refraction was reduced from a preoperative mean of +4.38 +/- 2.87 diopters (D) to -0.54 +/- 2.59 D at last postoperative follow-up (P < .001). No statistically significant difference was observed in mean refractive astigmatism before and after the corneal suture (P = .15). Before surgery, no eye presented with best spectacle-corrected visual acuity (BSCVA) > or = 20/20. At final follow-up, 3 (17.6%) eyes attained this level. Seven (41.2%) eyes improved their BSCVA by > or = 2 Snellen lines. One (5.9%) eye lost 2 Snellen lines of BSCVA.

CONCLUSIONS

Corneal suture can be used to correct RK-induced hyperopia, improving the corneal asphericity in an attempt to stabilize these corneas. It appeared to be effective even for high degrees of hyperopia and in cases with associated irregular astigmatism or open incisions.

Surgical Correction of Hyperopia

Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.

Laser in situ keratomileusis outcomes following radial keratotomy, astigmatic keratotomy, photorefractive keratectomy, and penetrating keratoplasty

PURPOSE

To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) to enhance refractive status following other corneal surgical procedures.

SETTING

Clinical office-based practice.

METHODS

Seventy-one eyes of 57 patients had LASIK for refractive errors following radial keratotomy (n = 22), astigmatic keratotomy (n = 13), photorefractive keratectomy (n = 18), and penetrating keratoplasty (n = 18). A Moria LSK-1 microkeratome was used with a Visx S2 or Wavelight Allegretto excimer laser. Data were acquired by retrospective chart review of all appropriately qualified patients.

RESULTS

The mean preoperative manifest refractive spherical equivalent (MRSE) was -3.93 diopters (D) +/- 2.83 (SD) in myopic eyes and +1.43 +/- 1.79 D in hyperopic eyes. The mean time from the initial corneal surgical procedure to LASIK was 65.0 months. The mean post-LASIK follow-up was 9.40 months (range 1 to 42 months). Postoperatively, the mean MRSE was -0.85 +/- 1.42 D in myopic eyes (P<.0001) and -0.16 +/- 1.09 D in hyperopic eyes (P<.0001). Enhancement by LASIK was required in 14% of eyes.

CONCLUSION

In eyes that have had a variety of previous corneal surgeries, LASIK offers a safe and predictable method for enhancing refractive results.

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.

LASIK for hyperopia, hyperopic astigmatism, and mixed astigmatism

OBJECTIVE

To describe LASIK for hyperopia, hyperopia with astigmatism, and mixed astigmatism and to examine the evidence to answer questions about the safety and efficacy of the procedure.

METHODS

A literature search conducted for the years 1968 to 2002 retrieved 118 citations. During review and preparation of this article, an additional 2 articles were included. The panel members selected 36 articles for the panel methodologist to review and rate according to the strength of evidence. A level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a level II rating to well-designed cohort and case-control studies; and a level III rating to case series, case reports, and poorly designed prospective and retrospective studies.

RESULTS

This assessment describes 5 nonrandomized interventional trials (level II), 3 nonrandomized comparative trials (level III), and 20 noncomparative case series (level III). Additionally, 6 single-case reports (level III) were included because they reported relevant complications, and 2 theoretical analyses (level III) were also considered. This assessment does not compare studies because many variables such as range of hyperopia, follow-up periods, lasers, microkeratomes, techniques, and surgeon experience have not been controlled.

CONCLUSIONS

For low (<3 diopters [D]) to moderate (3-5 D) hyperopia, results from published studies (levels II and III evidence) have shown that LASIK is effective and predictable in achieving very good to excellent uncorrected visual acuity, achieving postoperative refractions within 1 D of emmetropia, and is safe in terms of minimal loss of best-corrected spectacle vision. Although there are fewer data for hyperopic astigmatism, the results available seem to mirror the data for low to moderate hyperopia (levels II and III evidence). The postoperative results for both uncorrected vision and safety are less compelling, as greater amounts of hyperopia are treated (>4 to 5 D). Utilizing hyperopic LASIK for the treatment of consecutive hyperopia and astigmatism is also effective, although the ability to reduce hyperopic astigmatism after radial keratotomy is limited. Although a variety of ablation profiles can be used to treat mixed astigmatism, very good visual results have been reported (levels II and III evidence). Serious adverse complications leading to permanent visual loss are possible but, fortunately, very rare. There are insufficient data to compare one laser system with another or one ablation profile with another.

Laser in situ Keratomileusis for Residual Hyperopic Astigmatism After Conductive Keratoplasty

PURPOSE

To report a case of laser in situ keratomileusis (LASIK) in a patient with previous conductive keratoplasty.

METHODS

A 48-year-old man underwent conductive keratoplasty for low hyperopic astigmatism (manifest refraction OD: +2.25 -0.50 x 77 degrees; OS: +2.50 -0.50 x 105 degrees). Three months postoperatively, UCVA was 20/25 and BSCVA was 20/20 in both eyes; manifest refraction OD: -0.25 -0.75 x 110 degrees; OS: +0.75 -0.75 x 50 degrees. Sixteen months after the operation, regression of refractive outcome was (manifest) OD: +1.75 -1.25 x 90 degrees; OS: +2.50 -0.50 x 85 degrees; UCVA was 20/40 in the right eye and 20/63 in the left eye and BSCVA was 20/20 in both eyes. LASIK was performed for hyperopic regression in the left eye using an automated microkeratome (Alcon SKBM, 130-microm plate; Aesculap-Meditec MEL 70 excimer laser).

RESULTS

LASIK was uneventful and no intraoperative or postoperative complications related to the previous conductive keratoplasty procedure or LASIK were observed. Three months after LASIK and 19 months after the initial conductive keratoplasty, the patient's left eye was emmetropic; UCVA was 20/20(-2), BSCVA was 20/20 and manifest refraction was +0.25 -0.25 x 35 degrees. There was a uniform increase in topographical steepening. Visual acuity, refraction and topographic findings remained unchanged at 6 months.

CONCLUSIONS

Even though our experience is limited, treatment of hyperopia with LASIK in an eye with refractive regression following previous conductive keratoplasty resulted in a predicted refractive outcome, with no complications, and improvement in visual acuity at 6 months follow-up.

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.

Management of the corneal flap in laser in situ keratomileusis after previous radial keratotomy

PURPOSE

To report a method of managing the corneal flap in patients having laser in situ keratomileusis for the treatment of residual refractive errors after radial keratotomy.

DESIGN

Retrospective case series.

METHODS

Intraoperative dehiscence of radial keratotomy wounds occurred in 7 eyes of 6 patients treated with laser in situ keratomileusis for residual myopia or astigmatism or hyperopia 5 to 15 years after radial keratotomy. To minimize extension of these tears, the flap was initially rolled like a carpet toward the hinge before the ablation and then rolled away from the hinge to its original position after the ablation.

RESULTS

Using this method of managing the laser in situ keratomileusis flap in patients with previous radial keratotomy, all eyes had successful laser in situ keratomileusis, with 1-year postoperative uncorrected visual acuity ranging between 20/16 and 20/25. No eye had loss of spectacle-corrected vision or interface epithelial ingrowth.

CONCLUSIONS

Laser in situ keratomileusis has proved to be an effective treatment for correction of residual refractive errors after radial keratotomy. The surgical technique used in these cases was targeted at minimizing shearing forces in lifting the corneal flap to avoid extension of radial keratotomy wound dehiscence, which could lead to epithelial ingrowth and loss of best-corrected vision.

A Retrospective Study of Laser in situ Keratomileusis After Radial Keratotomy

PURPOSE

This is a retrospective study designed to present results of laser in situ keratomileusis (LASIK) after radial keratotomy (RK).

METHODS

Eighty eyes of 56 patients underwent LASIK for residual myopia, astigmatism, and hyperopia after RK. Absolute mean preoperative spherical equivalent refraction was 2.36 +/- 1.17 D. Best spectacle-corrected visual acuity (BSCVA) was 20/20 in 56% of eyes, 20/25 in 25%, 20/30 in 13%, 20/40 in 5%, and 20/60 in 1%. Uncorrected visual acuity was better than 20/40 in four eyes. Follow-up ranged from a minimum of 1 day after surgery to a maximum of 2 years, with an average of 6 months.

RESULTS

Mean final absolute spherical equivalent refraction was 0.62 +/- 0.611 D. Six eyes experienced a loss of BSCVA of one line, one eye lost two lines, and one lost more than two lines. Three eyes had one line of improvement and one eye had two lines of improvement. Uncorrected visual acuity was 20/20 in 21 eyes, 20/25 in 20 eyes, and 20/30 in 19 eyes. There was stromal opacity in two eyes, epithelial defects in two eyes, and epithelial ingrowth in four eyes.

CONCLUSION

LASIK may be an effective treatment for myopia, astigmatism, and hyperopia in patients with residual refractive error after RK. Extreme caution should be exercised due to the complexity of this group of patients.