[Outcomes of photorefractive keratectomy for post penetrating keratoplasty myopia and astigmatism]

To report the results of photorefractive keratectomy [PRK] with mitomycin-C [MMC] to correct myopia and astigmatism in patients who had previously undergone penetrating keratoplasty [PKP]. Thirty-eight eyes of 32 patients underwent PRK with MMC to correct astigmatism and myopia following PKP. Mean spherical equivalent [SE] was -5.2 +/- 4.7 D [diopter] and mean astigmatism was -2.4 +/- 3 D preoperatively which reached -3.1 +/- 3.1 D and -1.2 +/- 2.8 D 3 months after the operation respectively. The cornea was clear in 55.3%, had trace haze in 21.1%, moderate haze in 15.8% and severe haze in 7.9% of cases. PRK with MMC after PKP is a relatively safe and effective procedure. It reduces both the spherical error and the cylindrical component of the ametropia. Corneal haze is the major complication

[ comparison of ultrasonic and orbscan corneal pachymetry in corneal thickness measurement in the patients referred to Aban eye clinic, Isfahan]

With increased popularity of laser surgeries as a treatment for refractory errors and importance of pre-operative pachymetry for decreasing the complications of refractive surgery, correct measurement of corneal thickness is an important refractive procedure. There are two methods of corneal thickness measurement [phachymetry], optical method with orbscan system and ultrasonic method. This study was performed to compare the efficacy of these two methods in phachymetry. Corneal thicknesses of 324 eyes were measured with both orbscan and ultrasound phachymetry. Statistical analysis was performed using t-, ANOVA and correlation tests. Corneal thickness was 504.28 +/- 26.23micro using ultrasound pachymetry and 484.4 +/- 35.94micro using orbscan system. The difference between the two methods was statistically significant [p<0.001]. Corneal thickness measurement with orbscan and ultrasound systems might reveal different results and refractive surgeons should pay attention to this point

Correlation between corneal thickness and degree of myopic refractory error

Corneal thickness is an important factor in refractive surgeries such as Radial Keratotomy [RK], Photo Refractive Keratotomy [PRK] and Laser Insitu Keratomileusis [LASIK]. This study evaluated the correlation between this factor and the degree of myopic refractory error. In this cross-sectional study, 224 myopic eyes [112 patients] which had undergone LASIK operation were assessed. These patients had referred to Aban Eye Clinic, Isfahan, Iran, during August and September 2002. Corneal thickness was measured by ORB SCAN Topoghraphy, and cycloplegic refraction was performed with autorefratometery and retinoscopy. Suspected keratoconus cases and hyperopic patients were excluded. The patients' age was 27.2 +/- 1.36 in men [N = 35] and 30.13 +/- 1.04 in women [N = 77]. Mean value of myopic refractory error in male patients was 5.1 +/- 0.24D and in female patients was 3.8 +/- 0.36D. Mean of corneal thickness was 540 +/- 5.25 micro M and 530 +/- 5.88 micro M in male and female patients respectively. There was no correlation between the degree of myopia and corneal thickness in any of the patients. Also in this research, no relations between the age and myopia were found. Right eye [P > 0.5, r = 0.124] Left eye [P > 0.5, r = 0.104]. Based on our findings, corneal thickness and myopic refectory error do not seem to have any relations. [r = 0.039, p = 0.684]