The Effect of Anti-glaucoma Eyedrops and 0.1% Fluorometholone on Myopic Regression after LASIK or LASEK

PURPOSE: To evaluate the effect of combined medical treatment with anti-glaucoma eyedrops and 0.1% fluorometholone on visual acuity and refractive errors in patients complaining of blurred vision due to myopic regression after laser-assisted in-situ keratomileusis (LASIK) or laser-assisted sub-epithelial keratectomy (LASEK). METHODS: This study comprised 155 patients (155 eyes) who were diagnosed with myopic regression after LASIK or LASEK and received medical treatment from January 2015 to January 2016. The visual acuity and refractive errors were compared before and after medical treatment and evaluated to determine whether the results differ between LASIK and LASEK. RESULTS: The mean time of medical treatment was 64.1 ± 36.8 months after surgery. The responder group whose vision was improved and whose myopic error was decreased after medical treatment was comprised of 63 patients (41%). Their visual acuity in this group improved -0.21 ± 0.11 logMAR, and the amount of myopic error decreased 0.56 ± 0.32 diopters. The full responder group was 24 patients (15%), and the partial responder group was 39 patients (26%). The frequency of response to medical treatment was higher after LASIK than after LASEK, but the difference was not statistically significant. CONCLUSIONS: The combined medical treatment with anti-glaucoma eyedrops and 0.1% fluorometholone was effective in 41% of patients with regard to visual acuity improvement when used for post-LASIK or post-LASEK myopic regression. The medical treatment was effective after both LASIK and LASEK.

Clinical Outcome of Retreatment after Refractive Surgery

PURPOSE: To evaluate the clinical outcome of retreatment after refractive surgery. METHODS: Retrospective analysis of 38 eyes of 24 patients who received retreatment surgery after refractive surgery from August 2008 to May 2013 was performed. Pre-initial surgery characteristics and the reason for retreatment were investigated, and preand post-retreatment uncorrected visual acuity, best corrected visual acuity, safety index, efficacy index, predictability, and postoperative complication were also investigated. RESULTS: Age at initial refractive surgery and retreatment were 28.50 +/- 7.29 years (17-49 years) and 31.21 +/- 6.49 years (21-49 years). Reasons for retreatment were myopic regression in 36 eyes (94.7%) and overcorrection in two eyes (5.3%). Methods of retreatment were laser subepithelial keratomileusis (LASEK) in 31 eyes (81.6%) and laser-assisted in situ keratomileusis (LASIK) in seven eyes (18.4%). Safety index values for all were above 1.0 and efficacy index values were 0.92, 0.93, and 0.95 in postoperative examination at 1 month, 3 months, and 6 months, respectively. No eye showed a decrease in best corrected visual acuity. One eye had transient hyperopia after retreatment, and two eyes had postoperative corneal opacity, but no eye experienced significant alteration in visual prognosis. CONCLUSIONS: Retreatment after refractive surgery was an efficient and safe clinical course in our clinic. No long-term complications were observed, and uncorrected visual acuity and refractive errors significantly improved after retreatment. In particular, LASEK can be considered as a safe and efficient retreatment modality without risk of keratectasia.

Clinical Characteristics of Glaucomatous Subjects Treated with Refractive Corneal Ablation Surgery

PURPOSE: To evaluate the clinical characteristics of newly diagnosed glaucomatous subjects who had a history of refractive corneal ablation surgery (RCAS). METHODS: Sixty-eight glaucomatous subjects who had a history of RCAS and 68 age- and visual field (VF) mean deviation-matched glaucomatous subjects with no history of RCAS were included. Intraocular pressure (IOP), central corneal thickness (CCT), VF, and retinal nerve fiber layer thickness determined by optical coherence tomography were assessed. Parameters were compared between patients with and without a history of RCAS. Between-eye comparisons in the same participant (more advanced vs. less-advanced eye, in terms of glaucoma severity) were performed in the RCAS group. RESULTS: With similar levels of glaucoma severity, those with a history of RCAS showed significantly lower baseline IOP and a thinner CCT than the eyes of individuals without a RCAS history (13.6 vs. 18.7 mmHg, 490.5 vs. 551.7 micrometer, all p < 0.001). However, the extent of IOP reduction after anti-glaucoma medication did not significantly differ between the two groups (17% vs. 24.3%, p = 0.144). In the between-eye comparisons of individual participants in the RCAS group, the more advanced eyes were more myopic than the less-advanced eyes (-1.84 vs. -0.58 diopter, p = 0.003). CONCLUSIONS: Eyes with a history of RCAS showed a similar level of IOP reduction as eyes without such a history after anti-glaucoma medication. Our finding that the more advanced eyes were more myopic than the less-advanced eyes in the same participant may suggest an association between glaucoma severity and myopic regression.

Clinical Characteristics of Glaucomatous Subjects Treated with Refractive Corneal Ablation Surgery

PURPOSE: To evaluate the clinical characteristics of newly diagnosed glaucomatous subjects who had a history of refractive corneal ablation surgery (RCAS). METHODS: Sixty-eight glaucomatous subjects who had a history of RCAS and 68 age- and visual field (VF) mean deviation-matched glaucomatous subjects with no history of RCAS were included. Intraocular pressure (IOP), central corneal thickness (CCT), VF, and retinal nerve fiber layer thickness determined by optical coherence tomography were assessed. Parameters were compared between patients with and without a history of RCAS. Between-eye comparisons in the same participant (more advanced vs. less-advanced eye, in terms of glaucoma severity) were performed in the RCAS group. RESULTS: With similar levels of glaucoma severity, those with a history of RCAS showed significantly lower baseline IOP and a thinner CCT than the eyes of individuals without a RCAS history (13.6 vs. 18.7 mmHg, 490.5 vs. 551.7 micrometer, all p < 0.001). However, the extent of IOP reduction after anti-glaucoma medication did not significantly differ between the two groups (17% vs. 24.3%, p = 0.144). In the between-eye comparisons of individual participants in the RCAS group, the more advanced eyes were more myopic than the less-advanced eyes (-1.84 vs. -0.58 diopter, p = 0.003). CONCLUSIONS: Eyes with a history of RCAS showed a similar level of IOP reduction as eyes without such a history after anti-glaucoma medication. Our finding that the more advanced eyes were more myopic than the less-advanced eyes in the same participant may suggest an association between glaucoma severity and myopic regression.

Comparison of the Clinical Effect of the 1% Rimexolone with That of 0.1% Fluorometholone Following LASIK

PURPOSE: We compared therapeutic efficacy and steroid-induced IOP elevation of 1% rimexolone with that of 0.1% fluorometholone. METHODS: Of all LASIK treated eyes from March of 2001 to December of 2002 in Sungae General Hospital, 46 eyes were treated with 1% rimexolone and 46 eyes were treated with 0.1% fluorometholone. And we measured the degree of myopic regression (1 day, 1 month, 3 month) and intraocular pressure (1 month). RESULTS: Statistically signicant difference in therapeutic efficacy of myopic regression, and no statistically signicant difference in IOP were found. The therapeutic efficacy of 1% rimexolone was higher. CONCLUSIONS: We concluded that application of 1% rimexolone was more useful in myopic regression following LASIK rather than that of 0.1% fluorometholone.

Two Year Clinical Results of LASEK (Laser Epithelial Keratomileusis) for Correcting Myopia

PURPOSE: To evaluate efficacy and stability of vision correction and corneal haze of LASEK. METHODS: We reviewed 16 patients (30 eyes) who had undergone LASEK from October 1999 to April 2000. And we divided them into two groups and followed up 2 years (Group I: manifest refraction is from -3.0D to -6.0D, Group II: manifest refraction is from -6.25D to -10.25D). RESULTS: Mean uncorrected visual acuity (by logMAR) is improved from 1.28 +/- 0.40 to 0.02 +/- 0.05 one year after LASEK and reserved 0.02 +/- 0.04 two years after LASEK. Both groups showed over 20/25 of uncorrected visual acuity in one year and also two years after LASEK. Spherical equivalent less than 1.0 diopter in Group I and II was 85.7 % and 75.0 % of eyes one year after LASEK and 92.9 % and 81.3% of eyes two years after LASEK respectively. Myopic regression mostly occurred from 1 week to 2 months and remained stable after 1 year. Serious complications were not observed and corneal haze had no clinical significance. CONCLUSIONS: Efficacy of LASEK in the aspects of myopic correction and visual improvement is good and myopic regression and corneal haze was minimal. So LASEK is a good procedure to correct myopia.

The Effect of Corticosteroids on Myopic Regression after Laser in Situ Keratomileusis

PURPOSE: This study was to evaluate the effect of topical steroid treatment on eyes that showed myopic regression after LASIK. METHODS: A total of 26 patients (33 eyes) who showed myopic regression more than 1.00 diopter(D) confirmed by topography and pachymeter, were prospectively treated with 1% topical prednisolone acetate. Manifest refraction, Snellen uncorrected visual acuity and intraocular pressure(IOP) were measured before and after treatment. Topical steroids were administered every 2 hours for 3 days and 4 times a day for 11 days. Then the treatments were tapered in the eyes that showed over +0.50 D reversal of myopic regression. But it was immediately stopped in those eyes that showed no improvement or IOP increase. Pachymeter was taken in the improved group 4 weeks after the treatment. RESULTS: Fifteen eyes (45.5 %) showed over +0.50 D reversal of myopic regression(mean +/- SD +1.21 +/- 0.74 D, range: +0.50 ~ +2.75) and the uncorrected visual acuity increased (20/45 before treatment, 20/27 after treatment, p<0.01). The mean corneal thickness decreased (501.9 +/- 18.5 micrometer before treatment, 492.2 +/- 19.2 micrometer after treatment, p<0.01). Refractive effect of the steroid treatment remained stable with four of the eight eyes that could be followed up over six months. IOP was elevated in 3 eyes, but readily normalized with pressure-lowering agent. CONCLUSIONS: Topical steroid treatment for myopic regression after LASIK is partially effective and safe. It is recommendable to use topical steroid prior to performing surgical retreatment.

Four-Year Results of Laser In Situ Keratomileusis for High Myopia

PURPOSE: To evaluate the long term efficacy and stability of laser in situ keratomileusis (LASIK) for high myopia. METHODS: We investigated a retrospective study of 51 eyes that had LASIK to correct myopia. During the follow-up period, uncorrected visual acuity (UCVA) and refractive error were examined. The patients were divided into two groups according to preoperative refraction: Group 1, -6D to -10D (27 eyes); Group 2, -10D to -19D (24eyes). The data were analyzed using paired T-test and regression analysis. RESULTS: In group 1, mean spherical equivalent was -7.82+/-1.34D preoperatively and -0.19+/-1.35D at 2 months and -0.86+/-1.15D at four years postoperatively. In group 2, it was -12.66+/-2.66D preoperatively and -0.10+/-1.58D at 2 months and -1.76+/-1.78D at four years postoperatively. Myopic regression was statistically significant in both groups between 1 and 6 months, although the high myopia group had further regression. It was stable after 6 month in group 1(p>0.05) and continued during the four-years follow-up in group 2 (p<0.05). In group 1, uncorrected visual acuity was 0.84+/-0.15 at 6month and 0.64+/-0.27 at four year after LASIK . In group 2, it was 0.67+/-0.15 at 6month and 0.52+/-0.22 at four year after LASIK. At the last examination, the spherical equivalent was within 1.00D in 63% and 42%, respectively. UCVA was 0.5 or better in 74% and 50% of eyes in group 1 and group 2. CONCLUSIONS: According to these results, LASIK was safety and effective in the correction of high myopia but myopic regression was continuous progressed in myopia up to 10.00D.

Causes of the Lower Uncorrected Visual Acuity than 20/40 after LASIK

PURPOSE: To evaluate the causes of low uncorrected visual acuity below 20/40 after LASIK (laser in situ keratomileusis). METHODS: 289 eyes (more -6.0 D myopia) that had LASIK between July 1997 and December 1999 by one surgeon were observed for at least 6 months. We evaluated their uncorrected visual acuity and ocular state. RESULTS: 51 eyes (17.64%) of 289 eyes have lower uncorrected visual acuity than 20/40 after LASIK. The causes were myopic regression (22/51), decentering (10/51), undercorrection of myopia (5/51), corneal ectasia (5/51), undercorrection of astigmatism (4/51), central island (2/51), free flap (1/51), postoperative flap displacement (1/51) and incomplete keratome pass (1/51). CONCLUSION: Although LASIK is a safe and effective procedure, many patients had lower uncorrected visual acuity less than 20/40 after LASIK. We must be able to manage correctable factors among the causes above.

Nine-Year Results of Excimer Laser Photorefractive Keratectomy for Myopia

PURPOSE: To evaluate the long term stability, complications, and causative factors in eyes that had photorefractive keratectomy (PRK) for myopia. METHODS: We investigated the results of photorefractive keratectomy (PRK) on 72 consecutive myopic eyes (45 patients) with follow-up of 9 years by using Eximed UV 200LA laser (Summit technology, USA). The patients were divided into two groups according to preoperative myopia : group 1 with diopters between -3.25 D and -6.50 D, group 2 with diopters above -6.50 D. During the follow-up period, 1, 2, 3, 5, 7 and 9 years, refractive error, uncorrected and best corrected visual acuity and corneal opacity were examined. Preoperative myopia ranged from -3.25 D to -9.12 diopters (D), with astigmatism of less than 1.50 D. The excimer laser was set to a maximum correction of -6.50 D at a 5.0mm diameter ablation zone. Patients with more than -6.50 Dmm of myopia had double-pass PRK with two different ablation zone sizes (5.0 and 4.5 mm). The data were analyzed using paird T-test and Regression analysis. RESULTS: Mean refractive error 9 years after PRK was -2.10+/-0.99 D. It was -1.67+/-0.71 D in moderately myopic eyes (less than 6.50 D) and -2.60+/-1.04 D in highly myopic eyes (more than 7.0 D). The Myopic regression rate markedly decreased after 2years in moderate myopic group but after 3 years in highly myopic group (P<0.01). The most possible causative factor for myopic regression were pre-PRK refraction (P<0.01) and its relative risk was 4.21: At 9 years, 92.3% eyes achieved uncorrected visual acuity of 0.5 or better group1, and 78.7% in group2. Moderate corneal haze was present in 2eyes in group 2. CONCLUSION: According to these results, we thought that eximer PRK was effective for myopia under -9.62 D. Myopic regression was stabilized after 3 years of PRK.

One Year Clinical Result of Successful LASIK Using VISX Star

To evaluate the one year efficacy, visual recovery and stability for the correction of myopia we reviewed the 65 eyes successfully underwent LASIK from Dec.1996 to June 1997. All the visual acuity was calculated by logarithmic mean scale.Mean uncorrected visual acuity[UCVA]was 1.39 +/-0.44 and 0.16 +/-0.12 before and one year after LASIK, respectively.One year visual outcome after LASIK was better in the eyes under -6.0 diopter[D]than the eyes over-10.0D [P<0.05].Uncorrected visual acuity of 1 year after LASIK was 20/25 or better in all myopic eyes better than -6.0D and in 36 percent of eyes over-10.0D.Mean spherical equivalent[SE]was -8.71D and -0.8D before and one year after LASIK, respectively.Spherical equivalent less than +/- 1.0 diopter was 85.7 percent of the eyes under -6.0D and in 39.3 percent of the eyes over than -10.0D.Myopic regression was prominent from 1 week to 2months[P<0.05]and stable after 6 months[P<0.05]. With these results it was found that the efficacy of LASIK in visual acuity and the stability of myopic regression were related reversely with severity of myopia.

Seven Year Results of Excimer Laser Photore fractive Keratecto my for Myopia

To evaluate the long term efficacy of excimer laser photorefractive kerate-ctomy (PRK)for myopia, 37 eyes of 20 patients were observed for 7 years after PRK.The patients were divided into three groups according to preop-erative myopia :group 1 with diopters between -2.00 and -5.75, group 2with diopters between -6.00 and -9.75, group 3 with myopia over -10.0 diopter.During the follow up period, 6 months, 1 year, 2 years and 7 years, refractive error, uncorrected and best corrected visual acuity and corneal opacity were examined. Mean refractive errors seven years after PRK were changed significantly. In group 1 and group 3, long-term regression occured between 2 and 7 years (paired t test:p=0.01, p=0.01, respectively).In group 2, long-term regression occured between 1 and 7 years (p=0.02).At 7 years, in group 1, 92%of eyes, in group 2, 69%of eyes, and in group 3, 20%of eyes achieved uncorrected visual acuity of 0.5 or better.The group 3 showed a trend toward greater regression. With these results we thought that excimer PRK was effective for mild-to-moderate myopia, while less effective for high myopia.Despite the effi-cacy, we believe that slow myopic regression can continue up to 7 years and further follow-up is essential to assess long-term effect.

The Effect of Topical Corticosteroid Treatment On Myopic Regression after Photorefractive keratectomy: Long-term Follow-up

To evaluate the long-term effect of topical corticosteroid treatment on reversing myopic regression after excimer laser potorefractive keratectomy(PRK), 118 eyes of 103 patients demonstrating myopic regression of more than-1.00D were treated with 0.1% dexamethasone eye solution, and the changes in visual acuity, refraction and corneal haze after treatment were assessed. The mean preoperative refraction was -6.89D. The mean myopic regression was -1.72D which improved to +0.12D after treatment and the mean uncorrected visual acuity also improved from 0.51 to 0.92. Corneal haze of Grade 1.04 at the time of regression decreased to Grade 0.61 after treatment. All eyes showed improvement after dexamethasone treatment but among 88 eyes which underwent long-term follow-up f the average 21.2 months(6~24 months), 48.9%(43 eyes) showed at least one 1episode of repeated regression while 51%(45 eyes) remained stable. Whether regression developed again depended on the changes of corneal haze(p<0.05). This study suggest that the effect of topical corticosteroid on reversing myopic regression after PRK lasted long in a significant number of eyes, retreat mint which also would have some complications.

Excimer Laser Photorefractive Keratectomy: Two-year follow-up

Excimer laser photorefractive keratectomy(PRK) for myopia has been performed recently by refractive surgeons, in spite of myopic regression and corneal opacity following excimer PRK. We analyzed refractive change, corneal opacity, and uncorrected visual acuity of 313 eyes (233 patients) for one year and 115 eyes(83 patients) for two years after excimer PRK. The patients were divided tnto 3 groups accordign to theit refractive errors [group 1 (n=123 eyes): from -2.25D to -6D, group 2 (n=145 eyes) : from -6.25D to -10D, and group 3 (n=45 eyes): less than -19.25D]. Mean refractive errors one year after excimer PRK were -0.31+/-0.57D, -0.54+/-0.90D, and -1.71+/-2.01D in group 1, 2, and 3, respectively. These errors were increased to -0.45+/-0.68D, -0.90+/-1.20D, and -3.37+/-3.20D two years after excimer PRK in group 1, group 2, and group 3, respectively. These changes were staistically significant in group 2 (p=0.000) and group 3 (p=0.015), not in group 1 (p=0.426). Corneal opacity was more severe in group 3 than in group 1 and 2 and decreased depending on time passing by. Diopteric error within +/-1.0D from the attempted correction one year after excimer PRK was found in 89% of group 1, 74% of group 2, and 40% of group 3. These percentages were after excimer PRK. Uncorrected visual acuity equal to or better than 0.5 were 95% in group 1, 87% in group 2, and only 44% in group 3 two years after excimer PRK. With these results we thought that excimer PRK was effective and safe for myopia more than -6D, while unpredictable for myopia less than6D.

Excimer Laser Photorefractive Keratectomy: Two-year follow-up

Excimer laser photorefractive keratectomy(PRK) for myopia has been performed recently by refractive surgeons, in spite of myopic regression and corneal opacity following excimer PRK. We analyzed refractive change, corneal opacity, and uncorrected visual acuity of 313 eyes (233 patients) for one year and 115 eyes(83 patients) for two years after excimer PRK. The patients were divided tnto 3 groups accordign to theit refractive errors [group 1 (n=123 eyes): from -2.25D to -6D, group 2 (n=145 eyes) : from -6.25D to -10D, and group 3 (n=45 eyes): less than -19.25D]. Mean refractive errors one year after excimer PRK were -0.31+/-0.57D, -0.54+/-0.90D, and -1.71+/-2.01D in group 1, 2, and 3, respectively. These errors were increased to -0.45+/-0.68D, -0.90+/-1.20D, and -3.37+/-3.20D two years after excimer PRK in group 1, group 2, and group 3, respectively. These changes were staistically significant in group 2 (p=0.000) and group 3 (p=0.015), not in group 1 (p=0.426). Corneal opacity was more severe in group 3 than in group 1 and 2 and decreased depending on time passing by. Diopteric error within +/-1.0D from the attempted correction one year after excimer PRK was found in 89% of group 1, 74% of group 2, and 40% of group 3. These percentages were after excimer PRK. Uncorrected visual acuity equal to or better than 0.5 were 95% in group 1, 87% in group 2, and only 44% in group 3 two years after excimer PRK. With these results we thought that excimer PRK was effective and safe for myopia more than -6D, while unpredictable for myopia less than6D.

Clinical results of multizone photorefractive keratectomy for high myopia: Comparative study of two-zone and three-zone technique

In order to reduce a depth and slope of edge of ablation, the technique using 2 or 3 ablaiton zones has been applied to excimer laser photorefracitve keratectomy (PRK) for high myopic patients. In this study, excimer PRK using 2 zones (5.0mm; 100%, 6.0mm; 70%) or 3 zone (5.0mm; 100%, 5.5mm; 70%, 6.0mm; 50%) were used to each 10 patients having a range of refractive power between -8D and -9.5D randomly and divided into group 1 and group 2, respectively. corneal epithelial healing was delayed in group 2 comparaed to group 1 and the diference of that between group 1 and group 2 were statistical significant (P0.05). Uncorrected visual acuities of 20/40 or better were achieved in all patients of both groups at the last postoperrative visit (mean+/-SD, 22+/-3.4 weeks). Spherical equivalent less than 1.0 diopter was achieved in 60% of group 1 and 80% of group 2. As a complication 3 eyes (30%) in group 1 and 1 eye (10%) in group 2 lost 2 lines of best corrected visual acuity and thee was no statistically significant difference in both corneal haziness and patients' complaints between group 1 and group 2. With these results we could find a similar clinical results between excimer PRK using 2 zones and 3 zones by 6 months.

The Effect of Corticosteoid Treatment on Myopic Regression after Photorefractive Keratectomy

With the aim of reversing myopic regression after PRK, the effect of highdose topical corticosteroid in modulating changes in refraction and corneal transparency were assessed prospectively. Seventy-two eyes of 62 patients (mean preoperative SE -6.14D; -2.30 D to -11.50D), demonstrating myopic regression ranging between -0.75D to -5.33D (mean: -1.69D), were treated with 0.1% dexamethasone eye solution five times a day for averaging 2.8 weeks. The age of patient, amount of attempted correction and K-reading did not influenced statistically significantly on myopic regression. Uncorrected visual acuity, mean refraction before reintroducing corticosteroids (mean: 0.58, -1.69D) improved after corticosteroid treatment (mean: 0.85, -0.42D)(p<0.01). Corneal haze changed statistically significant from 0.80 +/- 0.61 to 0.53 +/- 0.40 after steroid treatment(p<0.01). Topical corticosteroid therapy can modulate refractive changes after PRK, appearing to improve myopic regression. However, a long term follow up will be necessary to determine the final refractive outcome of these eyes.

The Necessity of Topical Corticosteroid After Excimer Laser Photorefractive Keratectomy

The effect of topical steroid application on clinical results of 215 eyes(126 patients) performed with excimer laser photorefractive keratectomy (PRK) from July 1993 to July 1994 was evaluated, postopertively. The range of myopia was between -2.5 and -11.5 diopter and followed for 9 months after PRK with Summit Omnimed(TM). Topical corticosteroid or non-steroidal antiinflammatory drug (NSAID) was not applied for one month after operation in all cases. After one month, in cases of 115 eyes showing myopic regression of more than -1 diopter or stromal haziness of more than grade 1(delayed steroid group; DSG), 0.1% fluorometholone was applied 4 times daily for 4 weeks, then tapered according to the planned schedule. 46.5% (100 eyes, non-steroid group;NSG) did not show the myopic regression nor stromal haziness without treatment of fluorometholone throughout the follow-up period. Uncorrected visual acuity, spherical equivalent and corneal haziness were evaluated 1, 2, 4, 8, 12, 24, 36 week after operation. 73%(73 eyes) of NSG and 27%(30 eyes) of DSG showed a myopia less than 6.0 diopters preoperatively. The proportion of male was 36% in NSG and 50.4% in DSG. 88.1% of male high myopia(>6.0 diopters) needed 0.1% fluorometholone, while 17.6% of female moderate and mild myopia(

Evaluation of Multifactorial Factors Contributing to The Myopic Regression after PRK

The thirty four patients(60 eyes) of the same age group, sex and refractive error receiving eximer laser photorefractive keratectomy(PRK) from April 2, 1991 to May 2, 1993 were studied to evaluate the possible factors influencing the myopic regression. In this study, we didn't find any difference between regressed and nonregressed group in the individual parameters such as IOP, keratometer, corneal thickness, occupation, surgeon, hyperopic peak after PRK, and topographic analysis preoperatively and postoperatively. But, the increased tendency of myopic regression one the another eye experiencmg myopic regression on one eye showed statistically significance(P=0.005) and the same tendency was applied on the corneal haziness(P=0.012). We suggest corneal haziness is likely related to causing the myopic regression following PRK. Therefore, the surgeon should particularily try to prevent myopic regression in patients experiencing myopic regression on his one eye by minimizing coneal haziness following PRK.