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Biomedical subjects

George J C Jin

Publications and source records attributed to George J C Jin.

15 recordsLinked to original sources
PubMed2006

Intraocular lens exchange due to incorrect lens power.

PURPOSE: To evaluate patients who had intraocular lens (IOL) exchange for unexpected postoperative refractive errors, determine the sources associated with the errors, and derive an empiric approach to estimating the power for IOL exchange. DESIGN: Retrospective review of interventional case series. PARTICIPANTS: Twenty-two eyes that underwent IOL exchange for correcting unexpected refractive errors after cataract surgery with IOL implantation were reviewed. INTERVENTION: All the IOLs for IOL exchange were placed in-the-bag. The same type of IOLs was used for original IOL implantation and IOL exchange in 91% (20/22) of eyes. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), refraction, and reasons for IOL exchange. The equation derived from refractive change and change in IOL power was developed to calculate IOL power for exchange. RESULTS: Of the 22 cases, the identified reasons were keratometry errors in 5 (23%) and incorrect axial length (AL) determination in 3 (14%). In 3 other cases, a wrong IOL was implanted. After IOL exchange, 82% (18/22) of eyes were within +/-0.50 diopters (D) and 86% (19/22) within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/40 or better in 82% of eyes, and BSCVA was 20/40 or better in 95% (21/22) of eyes. The correlation between change of refraction and IOL power was significant (P<0.002). CONCLUSIONS: Among the identified causes, incorrect corneal power determination was the most frequent reason for incorrect IOL power implantation, followed by error in AL measurement and inserting a wrong IOL. The pre-exchange refraction can be used theoretically to calculate the IOL power for exchange.

Cataract Extraction↗
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

Analysis of intraocular lens power calculation for eyes with previous myopic LASIK.

PURPOSE: To evaluate the effectiveness of a manual keratometry (K) adjusted value for intraocular lens (IOL) power calculation in patients who underwent cataract surgery following previous myopic LASIK. METHODS: Sixteen eyes of 14 consecutive patients who underwent cataract surgery after previous LASIK were evaluated retrospectively. All IOL powers were calculated using an adjusted K value (K minus 1.0 diopter [D]) with the Binkhorst II formula aiming for -0.75 to -1.00 D final refraction. Additionally, the IOL power for each eye was retrospectively calculated using K, refractive-derived K, and adjusted K with the Binkhorst II, Holladay I, and SRK/T formulas. The final refraction was used as a criterion of accuracy of each approach. RESULTS: Uncorrected visual acuity > or = 20/40 was achieved in 14 (87.5%) of 16 eyes. The mean postoperative spherical equivalent refraction was -0.41 +/- 0.57 D (range: +0.50 to -2.00 D). Twelve (75%) of 16 eyes were within +/- 0.50 D of emmetropia and 15 (94%) of 16 eyes were within +/- 1.00 D. No eye was > +1.00 D. CONCLUSIONS: Using an adjusted K with the Binkhorst II formula, aiming for -0.75 to -1.00 D, and with the Holladay I formula, aiming for -0.50 to -1.00 D, measuring K with a regular manual keratometer permits determination of an IOL power after myopic LASIK without the need of preoperative LASIK refractive data.

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

Changing indications for and improving outcomes of intraocular lens exchange.

PURPOSE: To evaluate the indications for and outcomes of intraocular lens (IOL) exchange at the same clinical setting over the past decade, as well as compare the efficacy and safety of anterior chamber lens (AC-IOL) and posterior chamber lens (PC-IOL) implantation for IOL exchange. DESIGN: Retrospective, nonrandomized case series. METHODS: The charts of all patients who had an IOL exchange at the Eye Institute of Utah between January 1998 and December 2004 were reviewed. The rate, indications, and outcomes are compared with the data of our previous study conducted between 1986 and 1990. RESULTS: This study comprised 51 eyes of 51 consecutive patients. The rate of IOL exchange was 0.77% of all cataract surgeries during the time considered. Incorrect IOL power (41.2%), decentration/dislocation (37.3%), and glare (7.8%) were the most common indications for IOL exchange. An AC-IOL was used in 14 eyes (27.5%) and a PC-IOL in 37 eyes (72.5%) for IOL exchange. None of the PC-IOLs was sutured to the sclera or iris. Overall, 90.2% of patients obtained a best-spectacle corrected visual acuity (BSCVA) of 20/40 or better. All eyes in AC-IOL group and 94.6% of eyes in PC-IOL group maintained within 1 line or improved 2 to 5 lines of the pre-exchange vision. CONCLUSIONS: The improvements in IOL design and materials as well as surgical techniques have greatly minimized the incidence, changed the indications for, and improved the visual outcomes of IOL exchange over the past decade. Our study suggests that the open loop, flexible AC-IOL poses no greater risk than PC-IOL with respect to visual outcome and safety for IOL exchange. An AC-IOL may be preferable to a PC-IOL suture fixation for IOL exchange in the absence of posterior capsular support.

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↗
PubMed2003

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↗
PubMedDate not supplied

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↗