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Biomedical subjects

W Andrew Lyle

Publications and source records attributed to W Andrew Lyle.

8 recordsLinked to original sources

Laser in situ keratomileusis for primary and secondary mixed astigmatism.

PURPOSE: To evaluate and compare the efficacy, predictability, and safety of LASIK in the correction of primary and secondary mixed astigmatism after previous LASIK surgery. DESIGN: Retrospective, comparative case series. METHODS: The retrospective study included 118 eyes having LASIK with the LADARVison 4000 excimer laser (Alcon Surgical, Orlando, Florida) to correct mixed astigmatism. The eyes were divided into two groups: in group A (n = 64), LASIK was for primary mixed astigmatism and in group B (n = 54), LASIK was for secondary mixed astigmatism. Mean follow-up was 10.6 +/- 5.90 months. RESULTS: Overall, the postoperative UCVA was 20/20 in 51% of eyes and 20/40 or better in 97% of eyes at the last visit. The mean refractive cylinder was -2.18 +/- 0.94 D preoperatively and -0.56 +/- 0.56 D postoperatively. Sixty-one percent of eyes had a refractive cylinder of 0.50 D or less. One eye lost 2 lines of BSCVA (0.8%). None of the eyes had postoperative BSCVA worse than 20/25. The difference of preoperative cylinder was significant between group A and group B (P = .000). However, there was no statistical difference of postoperative refraction and UCVA between these two groups. At 12 months, the mean vector magnitude achieved was 93% of intended cylinder correction with a mean angle of error of -3.0 +/- 16 degrees. CONCLUSIONS: LASIK is a safe, effective, and predictable procedure to treat both primary and secondary mixed astigmatism. Nomogram adjustment with spherical and astigmatism components individually may improve refractive outcomes.

Adult↗

Late-onset idiopathic diffuse lamellar keratitis after laser in situ keratomileusis.

We report a case of late-onset diffuse lamellar keratitis (DLK) in the left eye of a 56-year-old white woman 3 years after uneventful bilateral laser in situ keratomileusis (LASIK). Slitlamp examination revealed stage 3 DLK with diffuse, multifocal, dot-like, and granular haze in the interface. The DLK did not have an obvious causative agent such as trauma or epithelial defects and responded rapidly to topical corticosteroid therapy. Surgery was performed to relift the flap, remove cellular infiltrates, and obtain cultures. The microbiology culture was negative. This case indicates that DLK can occur several years after LASIK without an obvious cause.

Administration, Topical↗

Laser in situ keratomileusis for primary hyperopia.

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of hyperopic laser in situ keratomileusis (H-LASIK) over a 24-month period and analyze topographic changes after H-LASIK to assess topographic pseudokeratectasia (TPKE) following H-LASIK. SETTING: Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: This prospective study included 139 eyes of 77 patients having H-LASIK for primary hyperopia. The mean follow-up was 15.6 months +/- 7.6 (SD) (range 6 to 48 months). One hundred twenty-two eyes (88%) were followed at 1 year and 36 eyes (26%) at 24 months. Topographic pseudokeratectasia was defined as 1 or more positive keratoconus screening findings in an eye with topographic central or inferior steepening detected by the Topography Modeling System but without corneal thinning or progressive change. RESULTS: The mean spherical equivalent manifest refraction was +2.39 +/- 0.99 diopter (D) preoperatively and -0.05 +/- 0.61 D at the last visit. Ninety-one percent of eyes were within +/-1.00 D of emmetropia and 71% of the eyes were within +/-0.50 D. Uncorrected visual acuity of 20/20 or better was present in 42%, 20/25 in 63%, and 20/40 or better in 93% of eyes. Loss of 2 lines of BSCVA occurred in 2 eyes (1.4%). In 1 eye, ischemic optic neuropathy occurred, and in another, choroidal neovascularization developed postoperatively. Topographic pseudokeratectasia was detected in 28% to 56% of eyes postoperatively. No significant difference between postoperative visual and refractive outcome, regression, or irregularity was found between the eyes with or without TPKE. CONCLUSION: Hyperopic LASIK appears to be an effective, predictable, and safe procedure to correct low to moderate primary hyperopia. Topographic pseudokeratectasia, which was observed after H-LASIK with a keratoconus-like topographic pattern in otherwise normal eyes, may represent a relatively static condition.

Adult↗

Laser in situ keratomileusis for consecutive hyperopia after myopic LASIK and radial keratotomy.

PURPOSE: To evaluate and compare the efficacy, predictability, and safety of hyperopic laser in situ keratomileusis (H-LASIK) for the correction of consecutive hyperopia after myopic-LASIK (M-LASIK) and radial keratotomy (RK). SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: Seventy-seven eyes of 64 patients were studied. The eyes were divided into 2 groups based on the prior refractive procedures: in Group A (n = 34), H-LASIK was performed for overcorrection after M-LASIK and in Group B (n = 43), for overcorrection after RK. All eyes were included in the analysis of intraoperative and postoperative complications. Only eyes with a minimum follow-up of 6 months were included in the analysis of visual and refractive results. Among these 66 eyes, 30 were in Group A and 36 were in Group B. The mean follow-up in these eyes was 12.34 months +/- 5.95 (SD) (range 6 to 33 months). RESULTS: Overall, the mean spherical equivalent (SE) was +1.88 +/- 0.91 diopters (D) preoperatively and -0.37 +/- 0.65 D at the last visit. Eighty-three percent of eyes were within +/-1.00 D of emmetropia, and 66% were within +/-0.50 D. The uncorrected visual acuity (UCVA) was 20/20 in 39% of eyes and 20/40 or better in 92% of eyes. The preoperative SE was +1.43 +/- 0.59 D in Group A and +2.26 +/- 0.96 D in Group B; the difference in the preoperative SE was significant (P=.001). However, there was no statistically significant between-group difference in postoperative refraction and UCVA. One eye in Group B (3%) lost 2 or more lines of best corrected visual acuity. Corneal ectasia developed in 1 eye in Group B 11 months after H-LASIK. A sliver occurred in 1 eye in Group A after the flap was recut. CONCLUSION: Hyperopic LASIK was equally effective and predictable in treating consecutive hyperopia after overcorrected M-LASIK and overcorrected RK. The safety of the procedure in the RK group appeared to be inferior to that in the M-LASIK group. Although vision-threatening complications are rare after H-LASIK retreatment, corneal ectasia developed in 1 eye in the RK group.

Adult↗

Interface fluid after laser in situ keratomileusis.

PURPOSE: To describe a case of interface fluid after laser in situ keratomileusis (LASIK) and review the literature on this rare complication after LASIK. METHODS: We present a case report and literature review. Articles for this review were chosen from electronic database and manual literature searches. MEDLINE searches were made from 1990 to April 2002, using the key words "interface fluid" and "LASIK." RESULTS: A 40-year-old man had uneventful LASIK for residual refractive error from previous penetrating keratoplasty in his right eye. Diffuse lamellar keratitis began 1 day postoperatively. Topical corticosteroids were administered. Six weeks after LASIK, a layer of interface fluid developed. Intraocular pressure was 9 mmHg when measured centrally by Goldmann applanation tonometry and 30 mmHg by Tono-pen tonometry. The interface fluid resolved with antiglaucoma agents and corticosteroids combined with cyclosporine. CONCLUSIONS: This case, along with other reported cases, demonstrate the clinical features of interface fluid after LASIK.

Adult↗