PubMed Health⌕ Search

Biomedical subjects

Kevin H Merkley

Publications and source records attributed to Kevin H Merkley.

7 recordsLinked to original sources
PubMed2006

Retreatment after wavefront-guided and standard myopic LASIK.

PURPOSE: To assess and compare the clinical outcomes of conventional LASIK retreatments after primary wavefront-guided and standard myopic LASIK. DESIGN: Retrospective review of interventional case series. PARTICIPANTS: One hundred fifty-four eyes of 114 consecutive patients underwent a conventional LASIK retreatment after previous wavefront-guided and standard myopic LASIK. The eyes were divided into two groups: standard conventional myopic LASIK (SM) (n = 101) and wavefront-guided myopic LASIK (WM) (n = 53). INTERVENTION: Retreatment LASIK was performed by lifting the original flap and using an excimer laser. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and complications were evaluated at a mean follow-up of 7.8+/-5.5 months after retreatment (range, 3-26). RESULTS: At the last visit, mean spherical equivalents (SEs) were -0.17+/-0.42 diopters (D) in the SM group and -0.11+/-0.34 D in the WM group (P = 0.394). An SE of +/-0.50 D was achieved in 87% (88/101) of SM eyes and 91% (49/53) of WM eyes. Seventy-five percent of eyes in both groups had UCVA> or =20/20. All eyes in the WM group and 98% of eyes in the SM group had 20/30 or better UCVA. All eyes in both groups had a postoperative BSCVA of 20/25 or better. No eyes lost 2 lines of BSCVA in either group. No sight-threatening complications were encountered. The number of eyes with pre-retreatment optical symptoms was reduced to half after retreatment. CONCLUSIONS: Our results suggest that retreatment with conventional LASIK is a safe, effective, predictable way of dealing with different types of residual refractive errors after both wavefront-guided and standard myopic LASIK.

Adult↗
PubMed2006

Conventional and wavefront-guided myopic LASIK retreatment.

PURPOSE: To assess the clinical outcomes of conventional and wavefront-guided myopic laser in situ keratomileusis (LASIK) retreatment. DESIGN: Retrospective, nonrandomized case series. METHODS: The study comprised a cohort of 97 eyes having LASIK retreatment for residual myopia after primary LASIK. The eyes were divided into two groups: conventional retreatment (CR) group (n = 74) and wavefront-guided retreatment (WR) group (n = 23). The retreatment LASIK was performed using LADARVison 4000 with/without CustomCornea (Alcon Surgical, Orlando, Florida, USA). The mean follow-up was 8.9 +/- 5.8 months after retreatment (range three to thirty-six months). RESULTS: The mean pre-retreatment spherical equivalent (SE) was -0.93 +/- 0.41 diopters in the CR group and -0.84 +/- 0.48 diopters in the WR group (P = .409). At the last visit, the mean SE was -0.19 +/- 0.28 diopters and +0.32 +/- 0.47 diopters, respectively (P < .001). An SE of +/- 0.50 diopters was achieved in 92% (68 of 74) of CR eyes and 65% (15 of 23) of WR eyes. In the CR group, 85% eyes had a uncorrected visual acuity (UCVA) > or = 20/20 and 99% > or = 20/40, and in the WR group, 35% and 100%, respectively. None of the CR eyes and 17% (4 of 23) of WR eyes lost two lines of best spectacle-corrected visual acuity (BSCVA). Nine percent (7 of 74) of CR eyes and 30% of WR eyes (7 of 23) had optical symptoms before retreatment, the number was reduced to 1% (1 of 74) and 4% (1 of 23), respectively. CONCLUSIONS: In the study period with the current equipment, our results showed that conventional LASIK retreatment was superior to wavefront-guided LASIK retreatment in both efficacy and safety.

Adult↗
PubMed2006

Laceration and partial dislocation of LASIK flaps 7 and 4 years postoperatively with 20/20 visual acuity after repair.

PURPOSE: To report two cases of late ocular trauma resulting in laceration of corneal flaps 7 and 4 years (cases 1 and 2, respectively) after LASIK. METHODS: A 49-year-old man sustained laceration of the flap and interface foreign body debris from construction material in the right eye 7 years after uneventful LASIK (case 1). A 33-year-old man had partial dislocation of the flap 4 years after LASIK in the left eye (case 2) due to a penetrating wood chip accident. Surgical procedures were performed to remove the foreign bodies and reposition the flaps. RESULTS: In case 1, postoperative uncorrected visual acuity (UCVA) was 20/25 with manifest refraction of -0.50 -0.50 x 110 corrected to 20/20. In case 2, UCVA was 20/20 with piano refraction after LASIK retreatment. CONCLUSIONS: Corneal LASIK flaps are susceptible to penetrating trauma, which can occur >7 years after the procedure. Proper everamanage ment of the trauma and LASIK flap can restore excellent visual acuity.

Adult↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2005

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↗