PURPOSE: To investigate the clinical effects of different orientation and magnitude of cyclotorsion on the compensation capacity of the WaveLight EX500 photorefractive keratectomy (PRK) platform. METHODS: This retrospective study comprised 400 eyes of 200 patients who underwent bilateral simultaneous PRK due to compound myopic astigmatism. The subjects were separated according to the orientation of cyclotorsion into incyclotorsion and excyclotorsion groups, and by the magnitude of cyclotorsion into group 1 (0.50 to 2.50 degrees), group 2 (3.00 to 5.00 degrees), group 3 (5.50 to 7.50 degrees), and group 4 (8.00 to 9.50 degrees). RESULTS: The mean magnitude of cyclotorsion was 3.50 ± 2.4 degrees (0.50 to 9.50 degrees) in the incyclotorsion group and 3.32 ± 2.3 degrees (0.50 to 9.50 degrees) in the excyclotorsion group (p = 0.617). The postoperative refractive outcomes of the incyclotorsion and excyclotorsion groups were similar (p > 0.05 for all). The postoperative mean cylindrical refractive error was −0.32 ± 0.3 diopters (D, −1.25 to 0.00 D) in group 1, −0.47 ± 0.2 D (−2.00 to 0.00 D) in group 2, −0.62 ± 0.2 D (−1.00 to −0.25 D) in group 3, and −0.91 ± 0.2 D (−1.50 to −0.50 D) in group 4 (p < 0.001). Preoperative cylindrical refractive error was positively correlated with magnitude of cyclotorsion (r = 0.125 and p = 0.013), which was also positively correlated with postoperative cylindrical refractive error (r = 0.600 and p < 0.001). CONCLUSIONS: Incyclotorsion and excyclotorsion can be equally compensable in the WaveLight EX500 PRK platform for compound myopic astigmatism. A value of ≤2.50 degrees cyclotorsion magnitude was observed to be more compensable than higher degrees of cyclotorsion magnitude. Preoperative high astigmatism was associated with high cyclotorsion magnitude, which was also associated with a high degree of postoperative astigmatism.
Astigmatism ; Compensation and Redress ; Humans ; Myopia ; Photorefractive Keratectomy ; Refractive Errors ; Refractive Surgical Procedures ; Retrospective Studies

PURPOSE: We compared the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for the correction of hyperopia. METHODS: Patients who underwent PRK or LASIK, under +6.00 diopters (D) hyperopia and under −2.00 D astigmatism were included. In total, 21 patients (38 eyes) underwent PRK surgery and 25 patients (41 eyes) underwent LASIK surgery. We compared the visual acuity, refractive error, safety, and efficacy between the two groups. RESULTS: The manifest refractive spherical equivalent (MRSE) of the PRK and LASIK groups at 1 and 3 months after surgery was significantly different between the two groups (p < 0.05). However, the MRSE was not significantly different at postoperative 6 and 12 months between the two groups. The uncorrected visual acuity (UCVA) of the PRK and LASIK groups at 1 month after surgery was significantly different between the two groups (p < 0.05). However, the UCVA was not significantly different at postoperative 3, 6, and 12 months between the two groups. The best-corrected visual acuity was not significantly different at postoperative 1, 3, 6, and 12 months between the two groups. The safety index was not significantly different between the two groups at postoperative 1, 3, 6, and 12 months. The efficacy index of the PRK group was lower than that of the LASIK group at 1 month after surgery. However, the efficacy index was not significantly different at postoperative 3, 6, and 12 months between the two groups. There was no statistically significant difference between the predictability of the two groups at postoperative 1 year. CONCLUSIONS: After PRK treatment, temporary myopic deviation was observed after 1 month, but there was no significant difference between the two treatments after 3 months of follow-up. In the correction of hyperopia, there was no significant difference between PRK and LASIK in efficacy or safety.
Astigmatism ; Follow-Up Studies ; Humans ; Hyperopia ; Keratomileusis, Laser In Situ ; Photorefractive Keratectomy ; Refractive Errors ; Visual Acuity

PURPOSE: To assess the validity of central corneal thickness (CCT) and corrected intraocular pressure (IOP) values obtained by tono-pachymetry in non-surgical and post-photorefractive keratectomy (PRK) eyes. METHODS: For the study, 108 young healthy participants and 108 patients who had PRK were enrolled. Measurements were randomly performed by tono-pachymetry, ultrasonic (US) pachymetry, and Goldmann applanation tonometry (GAT). CCT measurement by tono-pachymetry was compared to that of US pachymetry. The corrected IOP value obtained by tono-pachymetry was compared to that obtained by US pachymetry and GAT. The corrected IOP from US pachymetry and GAT was calculated using the identical compensation formula built into the tono-pachymetry. Bland-Altman plot and paired t-test were conducted to evaluate the between-method agreements. RESULTS: The mean CCT measurement using tono-pachymetry was significantly greater by 7.3 µm in non-surgical eyes (p < 0.001) and 17.8 µm in post-PRK eyes (p < 0.001) compared with US pachymetry. Differences were significant in both Bland-Altman plotand paired t-test. The mean difference of corrected IOP values obtained by tono-pachymetry and calculated from measurements by US pachymetry and GAT was 0.33 ± 0.87 mmHg in non-surgical eyes and 0.57 ± 1.08 mmHg in post-PRK eyes. The differences in the Bland-Altman plot were not significant. CONCLUSIONS: The CCT measurement determined using tono-pachymetrywas significantly thicker than that of US pachymetry. The difference in CCT was greater in post-PRK eyes than in non-surgical eyes. However, the corrected IOP value obtained by tono-pachymetry showed reasonable agreement with that calculated from US pachymetry and GAT measurements.
Compensation and Redress ; Corneal Pachymetry ; Healthy Volunteers ; Humans ; Intraocular Pressure* ; Manometry ; Photorefractive Keratectomy ; Ultrasonics

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.
Coma ; Humans ; Keratectomy, Subepithelial, Laser-Assisted ; Keratomileusis, Laser In Situ ; Laser Therapy* ; Phosmet* ; Photorefractive Keratectomy ; Refractive Errors* ; Refractive Surgical Procedures ; Treatment Outcome ; Visual Acuity

PURPOSE: To determine the effectiveness of the method for preventing corneal opacity and minimizing the intraocular pressure (IOP) increase after photorefractive keratectomy treated with 0.1% fluorometholone and tranilast (0.5% tranilast, Krix®, JW pharmaceutical, Seoul, Korea), especially in cases with elevated IOP. METHODS: The patients who underwent photorefractive keratectomy from May 2014 to May 2015 were enrolled in the present study. The data of 49 patients (49 eyes) with elevated IOP at 1 month postoperatively and who used 0.1% fluorometholone and tranilast eye drops (tranilast group) were analyzed and compared with the control group consisting of patients who underwent the same surgery from December 2012 to October 2013 but used only 0.1% fluorometholone. RESULTS: The visual acuity at postoperative 6 months was log MAR -0.08 ± 0.05 and log MAR -0.08 ± 0.04 in the tranilast group and control group, respectively. The eye drops were used postoperatively for 17.7 ± 3.3 weeks in the tranilast group and for 20.5 ± 3.7 weeks in the control group (p < 0.01). Anti-glaucoma eye drops were used for 18.4 ± 3.2 weeks and 20.9 ± 3.7 weeks postoperatively in the tranilast group and control group, respectively (p < 0.01). CONCLUSIONS: Adding tranilast eye drops to patients whose IOP was elevated because of 0.1% fluorometholone use after photorefractive keratectomy is an effective method for preventing corneal haze and minimizing IOP elevation.
Corneal Opacity ; Fluorometholone* ; Humans ; Intraocular Pressure ; Ophthalmic Solutions* ; Photorefractive Keratectomy* ; Seoul ; Visual Acuity

PURPOSE: To evaluate the effect of 0.05% cyclosporine A on the ocular surface after photorefractive keratectomy (PRK). METHODS: This retrospective study included 50 patients who underwent PRK. Patients were divided into two groups: 25 patients in group I were treated with topical 0.05% cyclosporine A with conventional medication, and 25 patients in group II were treated with conventional medication. Visual acuity (VA), tear break-up time (BUT), fluorescein staining score (F-stain), Schirmer I test, and ocular surface disease index (OSDI) were evaluated before surgery and 2 weeks, 1 month, 2 months, and 3 months after surgery. RESULTS: F-stain was significantly lower in group I than in group II at 2 weeks and 1 month (p < 0.05). There was no significant difference in uncorrected VA, BUT, Schirmer I test, or OSDI between the groups. However, group I showed a more effective pattern in dry eye. CONCLUSIONS: Combination treatment with 0.05% cyclosporine A was helpful for early ocular surface stability in patients with dry eye after PRK.
Cyclosporine* ; Fluorescein ; Humans ; Photorefractive Keratectomy* ; Refractive Surgical Procedures ; Retrospective Studies ; Tears ; Visual Acuity

No abstract available.
Adult ; Corneal Opacity/etiology/pathology/*surgery ; Female ; Humans ; Male ; Monitoring, Intraoperative/*methods ; Photorefractive Keratectomy/*adverse effects ; Postoperative Complications/etiology/pathology/*surgery ; Young Adult

PURPOSE: To analyze the time and incidence of increased intraocular pressure (IOP) induced by 0.1% fluorometholone used to prevent corneal haze after photorefractive keratectomy (PRK). METHODS: The present study included 826 patients (826 eyes) who underwent PRK between November 2012 and October 2013 and were followed up for more than 6 months. After surgery the patients were treated with 0.1% fluorometholone for 3-6 months according to their corneal conditions. The time and incidence was analyzed with the time and incidence when anti-glaucoma eye drops were used. RESULTS: Anti-glaucoma eye drops were used in 312 eyes (38%). The anti-glaucoma eye drops were started before 4 weeks postoperatively in 105 eyes (13%) and postoperatively at 5-8 weeks in 86 eyes (10%), at 9-12 weeks in 83 eyes (10%), at 13-16 weeks in 25 eyes (3%) and after 17 weeks in 13 eyes (2%). CONCLUSIONS: The overall incidence of increased IOP when treated with 0.1% fluorometholone for 3-6 months after PRK was approximately 38%. The incidence of increased IOP in each month for the first 3 months was almost identical implying that the longer 0.1 fluorometholone was used, the higher incidence of increased IOP occurred. These results can be helpful in educating patients regarding the risk of increased IOP and determining the follow-up period after PRK.
Fluorometholone* ; Follow-Up Studies ; Humans ; Incidence* ; Intraocular Pressure* ; Keratectomy, Subepithelial, Laser-Assisted ; Ophthalmic Solutions ; Photorefractive Keratectomy*

PURPOSE: To analyze the time and incidence of increased intraocular pressure (IOP) induced by 0.1% fluorometholone used to prevent corneal haze after photorefractive keratectomy (PRK). METHODS: The present study included 826 patients (826 eyes) who underwent PRK between November 2012 and October 2013 and were followed up for more than 6 months. After surgery the patients were treated with 0.1% fluorometholone for 3-6 months according to their corneal conditions. The time and incidence was analyzed with the time and incidence when anti-glaucoma eye drops were used. RESULTS: Anti-glaucoma eye drops were used in 312 eyes (38%). The anti-glaucoma eye drops were started before 4 weeks postoperatively in 105 eyes (13%) and postoperatively at 5-8 weeks in 86 eyes (10%), at 9-12 weeks in 83 eyes (10%), at 13-16 weeks in 25 eyes (3%) and after 17 weeks in 13 eyes (2%). CONCLUSIONS: The overall incidence of increased IOP when treated with 0.1% fluorometholone for 3-6 months after PRK was approximately 38%. The incidence of increased IOP in each month for the first 3 months was almost identical implying that the longer 0.1 fluorometholone was used, the higher incidence of increased IOP occurred. These results can be helpful in educating patients regarding the risk of increased IOP and determining the follow-up period after PRK.
Fluorometholone* ; Follow-Up Studies ; Humans ; Incidence* ; Intraocular Pressure* ; Keratectomy, Subepithelial, Laser-Assisted ; Ophthalmic Solutions ; Photorefractive Keratectomy*

PURPOSE: To evaluate the efficacy of combined photorefractive keratectomy (PRK) and cataract surgery in granular corneal dystrophy (GCD) patients with corneal stromal haziness compromising vision and cataract and clinically significant lens opacity. METHODS: Medical records of 12 eyes that underwent PRK and cataract surgery between August 2009 and November 2013 in patients with GCD and cataracts were retrospectively evaluated. All PRKs were performed with the VISX S4 IR (VISX, Santa Clara, CA, USA). The double K SRK-T formula or double K Hoffer Q formula and postoperative corrected K were utilized to determine the intraocular lens power in patients with prior PRK. Postoperative best corrected visual acuity (BCVA), spherical equivalent, presence of the central island using topography analysis and recurrence of corneal opacity after combined PRK and cataract surgery were evaluated. RESULTS: In all eyes, the PRK was successful and 3 eyes showed recurrence of corneal opacities without visual impairment during a mean follow-up of 36.6 months. The mean BCVA improved with an average increase of 4.63 lines (minimum 1 line, maximum 9 lines) and no patient showed any BCVA loss. Final spherical equivalent was -0.56 diopter (D) and the corneal central island was reported in only 1 eye. The Maloney method using the double-K formula with the SRK/T formula showed the lowest absolute error of 0.33 +/- 0.25 D. CONCLUSIONS: Combined PRK and cataract surgery are effective methods for improving BCVA if patients with GCD have both visually significant diffuse corneal haze and clinically significant lens opacity.
Cataract* ; Corneal Opacity ; Follow-Up Studies ; Humans ; Lenses, Intraocular ; Medical Records ; Photorefractive Keratectomy* ; Recurrence ; Retrospective Studies ; Vision Disorders ; Visual Acuity