Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

PURPOSE: The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. METHODS: We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. RESULTS: Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. CONCLUSIONS: The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

Recurrence after Modified Mini-Flap Technique for Pterygium Surgery

PURPOSE: To compare and analyze the clinical outcomes after the traditional mini-flap technique and a new modified mini-flap technique for pterygium surgery. METHODS: This is a retrospective, clinical outcome study of 39 eyes that received the existing mini-flap technique from January, 2004 to August, 2005, and 142 eyes that received the modified mini-flap technique from September, 2008 to December, 2010. We analyzed the recurrence rate of each mini-flap technique and the difference between the group that experienced recurrence and the group that did not. We also analyzed the difference between the group that received the mini-flap technique and the group that received the modified mini-flap technique. RESULTS: The recurrence rate of pterygium patients who received the mini-flap technique was 10.3% (4/39). The rate of those who received the modified mini-flap technique was 2.1% (3/142), which is statistically lower (p = 0.040). However, compared from the recurrence rate of 6.1% (3/49) that was reported in 2008, the recurrence rate of the modified mini-flap technique did not show any statistical significance (p = 0.165). From the comparison of demographic factors of the patients in each surgical technique group, in both recurred and not recurred group, the patient group in the modified mini-flap technique group whose pterygium was recurrd was the youngest (p < 0.001). CONCLUSIONS: The newly applied modified mini-flap technique is not only a safe method with low recurrence rate compared to the traditional mini-flap technique, but also a reliable surgical technique in both primary and recurred pterygium.

The Change of Corneal Sensitivity and Recovery of Corneal Nerve after Cataract Surgery

PURPOSE: To compare corneal sensitivity and recovery of corneal innervations after a temporal clear corneal incision in cataract surgery. METHODS: We measured changes to corneal sensitivity using Cochet-Bonnet esthesiometer in 25 eyes of 20 patients and analyzed corneal nerve density with confocal microscopy in 20 eyes of 20 patients who had undergone cataract surgery. The parameters were measured before, and at 1 week, 1 month, and 3 months after cataract surgery. RESULTS: The mean preoperative corneal sensitivity was 56.40+/-3.39 mm at the temporal corneal incision site, and there was a significantly decreased sensitivity of 29.80+/-2.69 mm and 42.40+/-4.36 mm postoperatively at 1 week and 1 month, respectively. Nonetheless, by three months, corneal sensitivity had returned to 56.00+/-2.89 mm and was not significantly different from measurements prior to the cataract surgery. The mean preoperative subbasal nerve density was 5296+/-1642 micrometer/mm2. After cataract surgery, the subbasal nerve density was significantly reduced to 4113+/-1421, 3555+/-1448, 4198+/-1239 micrometer/mm2 at 1 week, 1 month, and 3 months, respectively. CONCLUSIONS: Corneal sensitivity after cataract surgery returned to near preoperative levels within 3 months before complete restoration of normal corneal innervations. Therefore, regeneration of subbasal nerve fibers (, as determined by confocal microscopy,) requires more time than the return of corneal sensation after cataract surgery.

The Change of Corneal Sensitivity and Recovery of Corneal Nerve after Cataract Surgery

PURPOSE: To compare corneal sensitivity and recovery of corneal innervations after a temporal clear corneal incision in cataract surgery. METHODS: We measured changes to corneal sensitivity using Cochet-Bonnet esthesiometer in 25 eyes of 20 patients and analyzed corneal nerve density with confocal microscopy in 20 eyes of 20 patients who had undergone cataract surgery. The parameters were measured before, and at 1 week, 1 month, and 3 months after cataract surgery. RESULTS: The mean preoperative corneal sensitivity was 56.40+/-3.39 mm at the temporal corneal incision site, and there was a significantly decreased sensitivity of 29.80+/-2.69 mm and 42.40+/-4.36 mm postoperatively at 1 week and 1 month, respectively. Nonetheless, by three months, corneal sensitivity had returned to 56.00+/-2.89 mm and was not significantly different from measurements prior to the cataract surgery. The mean preoperative subbasal nerve density was 5296+/-1642 micrometer/mm2. After cataract surgery, the subbasal nerve density was significantly reduced to 4113+/-1421, 3555+/-1448, 4198+/-1239 micrometer/mm2 at 1 week, 1 month, and 3 months, respectively. CONCLUSIONS: Corneal sensitivity after cataract surgery returned to near preoperative levels within 3 months before complete restoration of normal corneal innervations. Therefore, regeneration of subbasal nerve fibers (, as determined by confocal microscopy,) requires more time than the return of corneal sensation after cataract surgery.

Comparison of Higher-order Aberrations between Eyes with Natural Supervision and Highly Myopic Eyes in Koreans

PURPOSE: To describe the characteristics and investigate the differences of higher-order aberrations (HOAs) between the eyes with a natural, uncorrected visual acuity (UCVA) of 20/12 and eyes with highly myopic eyes in Korean adults. METHODS: Thirty-one eyes of 20 subjects with UCVA of 20/12 (Group 1) and 54 eyes of 36 myopic patients with greater than -6 diopters (Group 2) were analyzed for type and magnitude of HOAs across a 6.0 mm pupil. HOAs were measured by Wavescan (VISX, Santa Clara, CA, USA) in natural scotopic conditions and were presented as root-mean-square (RMS: micrometer) in Belle aberration maps. RESULTS: The mean spherical equivalent (SE) of manifest refraction was -0.15+/-0.25 D (range: +0.37 to -0.50 D) in Group 1 and -7.25+/-0.78 D (range: -6.00 to -9.25 D) in Group 2. The total root-mean-square (RMS) values of HOAs for Group 1 and Group 2 were 0.28+/-0.09 micrometer and 0.27+/-0.087 micrometer, respectively (P>0.05). The mean values of coma, trefoil, and spherical aberration were 0.14+/-0.091 micrometer, 0.14+/-0.089 micrometer, 0.091+/-0.059 micrometer in Group 1 and 0.16+/-0.077 micrometer, 0.14+/-0.073 micrometer, 0.082+/-0.059 micrometer in Group 2, respectively. CONCLUSIONS: This study helped establish ocular aberration standards for those with natural supervision and those with highly myopic eyes among Koreans. Individuals with natural supervision had significant amounts of HOAs, and there was no significant difference in the amount of HOAs between the two groups. The index of higher-order aberrations may not be a perfect predictor of the amount of refractive error.

Comparison of Higher-order Aberrations between Eyes with Natural Supervision and Highly Myopic Eyes in Koreans

PURPOSE: To describe the characteristics and investigate the differences of higher-order aberrations (HOAs) between the eyes with a natural, uncorrected visual acuity (UCVA) of 20/12 and eyes with highly myopic eyes in Korean adults. METHODS: Thirty-one eyes of 20 subjects with UCVA of 20/12 (Group 1) and 54 eyes of 36 myopic patients with greater than -6 diopters (Group 2) were analyzed for type and magnitude of HOAs across a 6.0 mm pupil. HOAs were measured by Wavescan (VISX, Santa Clara, CA, USA) in natural scotopic conditions and were presented as root-mean-square (RMS: micrometer) in Belle aberration maps. RESULTS: The mean spherical equivalent (SE) of manifest refraction was -0.15+/-0.25 D (range: +0.37 to -0.50 D) in Group 1 and -7.25+/-0.78 D (range: -6.00 to -9.25 D) in Group 2. The total root-mean-square (RMS) values of HOAs for Group 1 and Group 2 were 0.28+/-0.09 micrometer and 0.27+/-0.087 micrometer, respectively (P>0.05). The mean values of coma, trefoil, and spherical aberration were 0.14+/-0.091 micrometer, 0.14+/-0.089 micrometer, 0.091+/-0.059 micrometer in Group 1 and 0.16+/-0.077 micrometer, 0.14+/-0.073 micrometer, 0.082+/-0.059 micrometer in Group 2, respectively. CONCLUSIONS: This study helped establish ocular aberration standards for those with natural supervision and those with highly myopic eyes among Koreans. Individuals with natural supervision had significant amounts of HOAs, and there was no significant difference in the amount of HOAs between the two groups. The index of higher-order aberrations may not be a perfect predictor of the amount of refractive error.