To compare the results of radial keratotomt an LASIK in low to medium myopia (1-7.5D). It was a randomized clinical trial study which was done on 136 eyes between 1998-1999. They were referred to Feiz hospital and Bassir clinic and were divided to two groups. The first group was 66 eyes which was operated by RK method and the second group 70 eyes was operated by LASIK technical post operatively for 6 months both group were examined regarding the remained amount of astigmatism, myopia or hyperopia and visual acuity. Post operatively 50% (33 eyes) the RK group and 74.3% (52 eyes) of LASIK with pre operatively simple myopia were emmetropic. 30.3% (20 eyes) of the Rk group and 8.6% (6 eyes) of the LASIK group with preoperatively simple myopia were undercorvected. 19.7% (13 eyes) of the RK group and 17.1% (12 eyes) of the LASIK group with preoperatively simple myopia were over corrected. 21.3% (10 eyes) in RK group and 50% (30 eyes) in LASIK group with preoperativly astigmatism became emmetropic. 42.6% (20 eyes) in RK group, 33.2% (20 eyes) in LASIK group with preoperatively astigmatism had residual astigmatism. 36.2% (17 eyes) in Rk. Group, 16.7% (10 eyes) in LASIK group with preoperatively astigmatism had induced astigmatism. Comparing lasik technique to RK, LASIK is safer, more predictable and needs less reoperation.      

Background and Objectives: Radial keratotomy is one of the current techniques in correction of myopia which has high prevalence in general population. The main purpose of this study was to evaluate changes in pattern and profile of corneal topography before, one week and third months after surgery. Secondary aims of this study were to record the subjective complaints and their correlation with topographic changes after surgery. Materials and Methods: In a clinical trial, comparison of corneal topography before and after RK was done in 50 eyes of 26 patients from 19/3/1997 to 20/9/2001. In all patients, routine eye examinations were performed before surgery along with determination of pattern and profile of corneal topographies (asphericity coefficient). Surgery were done under topical anesthesia with 0.2 mm diamond knife. Incision technique was as the American method with present standard nomograms. Corneal topography in first week and third months after surgery was done with special attention to central optical zone (COZ) pattern, presence of multifocality and asphericity coefficient. Patient’s complaints also were recorded.Results: The mean age of patients was 29 (18-60) years. 74% out of patients were male and 26% female. The mean duration of follow up was 10.5 months. The most common patterns of topography before surgery were asymmetric bow-tie (44%), symmetric bow-tie (40%), and spheric (8%). Corneal profile was prolate in 92% and spheric in 8% of cases. No case of oblate profile was found before surgery. Prevalent corneal patterns after surgery were regular polygonal (circular or elliptic) in 50% , Band like in 22%, and split in 28% of cases. Corneal multifocality was found in 38% of cases after surgery. Corneal profile was oblate in 94% and prolate in 6% of cases.Conclusion: Radial keratotomy induces various changes in corneal pattern and profile after surgery. Increased corneal asphericity and switching from prolate to oblate profile were noted. Multifocality in central flat zone can increase uncorrected visual acuity without considerable optical complications. Split pattern of central optic zone can cause diurnal fluctuation of vision.

History and Objectives: Due to the importance of correction corneal astigmatism in improvement of vision and reported various techniques, the present study was carried out to determine the effect of radial keratotomy on patients with astigmatism on patients referred to the Matini Hospital in 1996-1997. Materials and Methods: A quazi-experimental study was carried out in order to compare the vision of 34 patients (60 eyes) before and after the operation who were complaining from contact lens and eyeglass usage. Personal records, vision acuity with and without correction, type and extent of astigmatism were recorded. The criteria for operation were diopter of 1.25 and the best value for correction was set at 40.20. Radial keratotomay was carried out using 7mm Ophcal Zone on the basis of Lindstrom nomogram. Patients were followed for six month after the operation; and the effect of surgery was assessed on vision, the extent and type of astigmatism, and probable surgical side effects were recorded. T-test and Mc Nemor statistical test were carried out in order to determine the effect of keratotmy. Results: From 34 patients (9 male, 25 female; mean age 30±.5.2) 98.3% of patients had corrected vision by eye-glasses and contact lens use of more than 40.20. After surgery 82.5% of patients retained vision of 40.20. Mean esfer with astigmatism before the operation was 3.8±2.05 diaopter of myopia and after operation was 2±0.8. In 21.6% of patients side effects such as microperfusion and epithelial abnormality was observed. Conclusions: Surgical operation in order to correct astigmatism by radial keratotomy on the basis of Lindstrom nomogram is very effective and has minimal side effects. The results in the reduction of astigmatism and improvement of vision is such that it is recommended for corneal vision problems.      

Background: Radial keratotomy is a major type of refractive surgery. This study was performed to determine the association of visual evoked potential (VEP) and radial keratotomy. Materials and methods: In this cross-sectional descriptive-comparative survey, 25 patients under radial keratotomy attending to Basir Clinic in 2014 and 2015 were enrolled and the VEP results, including voltage and latency, were determined and compared with 25 control subjects. Results: The mean voltage was 5.6 ± 2.0 microvolt and 6.0 ± 2.2 microvolt in case and control groups, respectively (P>0.05). Mean latency duration was 95.7 ± 6.1 millisecond and 95.6 ± 5.7 millisecond in case and control groups, respectively (P>0.05). Conclusion: Totally, according to the obtained results, it may be concluded that there is no significant association between visual evoked potential and radial keratotomy. Keywords: VEP, Refractory surgery, Radial keratotomy.

Purpose: To report manifestation of granular corneal dystrophy after radial keratotomy (RK).Case Report: A 32-year-old man presented with white radial lines in both corneas. He had undergone uncomplicated RK in both eyes 8 years ago. Preoperative refraction had been OD: -3.5 -0.75@180 and OS: -3.0 -0.5@175. Uncorrected visual acuity was OD: 8/10 and OS: 7/10; best corrected visual acuity was 9/10 in both eyes with OD: -0.5 -0.5@60 and OS: -0.75 -0.5@80. Slit lamp examination revealed discrete well-demarcated whitish lesions with clear intervening stroma in the central anterior cornea consistent with granular dystrophy. Similar opacities were present within the RK incisions.Conclusion: Granular dystrophy deposits may appear within RK incisions besides other previously reported locations.

Purpose: To compare results of different methods for true corneal power determination and intraocular lens (IOL) power calculation formulas in 10 eyes of 7 patients with previous radial keratotomy (RK) with or without astigmatic keratotomy. Methods: In this case series study, we determined the corneal power of 10 eyes of 7 patients who had undergone RK with or without astigmatic keratotomy with two methods: the contact lens method (CLM) and the mean keratometry of the 3 mm zone in topography. In the next step, the IOL power for these eyes was calculated with the 3 formulas of SRK II, SRK T, and Holladay II; the latter was used for the IOL selection. Refractive results were determined 3 month after surgery. According to the rule that 1.5 diopter (D) change in IOL power results in 1.0 D change in a patient’s refraction at the spectacle plane, we estimated the manifest refraction of these eyes with other formulas and compared them with the results achieved by Holladay II formula.Results: Using the CLM and Holladay II formula, the postoperative manifest refraction spherical equivalent in 8 eyes ranged from -3.00 to+2.00 D. Both CLM and the mean keratometry of the 3 mm zone in topography lead to a greater degree of hyperopia after cataract surgery with SRK II formula than SRK T, and with SRK T than Holladay II. The mean spherical equivalent with mean keratometry of the 3 mm zone in topography and Holladay II formula was 0.08 D, and with CLM and Holladay II formula was -0.05 D.Conclusion: In this study, it seemed that after RK, the mean keratometry of the 3 mm zone in topography gives a better estimate of true corneal power compared with CLM, and that the Holladay II formula brings results closer to emetropia compared with SRK II and SRK T formulas.

Background and Objectives: Refractive errors have relatively higher prevalence in populations and myopia is byfar the most of them (25%). Many efforts have been made for correction of myopia. Radial Keratotomy (R.K) is one of them. The aim of this study was to evaluate the longterm refractive, keratometric and visual results after RK at Alavi Eye Hospital in Tabriz.Materials and Methods: This prospective study was done from 1997 to 2001 on 50 eyes from both sexes. In all patients slit lamp examination, fundus exam, refraction with and without cycloplegia, ultrasonic pachymetry and corneal topography were done and recorded. Through local anesthesia with a 0.2mm diamond knife, American incisions performed with standard nomograms (with regard to the age , sex , degree of myopia, pachymetry and topography). Slit lamp examination, visual acuity, checking refraction and topography were done in first week and 3 months after operation and in year 2001, as well as results analyzed with statistical methods.Results: the mean age of patients was 29 (74% male and 26% female). The mean duration of follow-up was 10.5 months. The average central pachymetry was 536.68µ, and had not meaningful relation with the degree of myopia. Average keratometry before and after operation was 43.75D and 40.67D respectively. The average myopia before surgery was -5.07 after which decreased to -1.50. Uncorrected visual acuity in 80% of the eyes was 8/10 or better. The most complaints after surgery were disturbances in night vision and blurred distance vision in 13 out of cases. Hyperopic shift was not seen and undercorrection was the most prevalent complication.Conclusion: With regard to the successful RK in correction of mild to moderate degrees of myopia, it is effective in cases of spectacle intolerance or vocational limitations.

It is essential for radial keratotomy surgery to determine corneal thickness preoperatively because appropriate incisional depth plays essential role in the effectiveness of surgery and prevention of corneal perforation. Any change in corneal thickness after RK will influence on selecting incisional depth for repeated surgery. Also relationship between changes in corneal thickness and age, sex and the interval between the operations is important. This research has been performed to address these problems.Medical records of 200 patients (101 males & 99 females) which were operated in Isfahan Farabi Hospital in 1995-1998, were studied. The informations were recorded in the information assembly tables including sex, age, interval between the operations and corneal thickness before and after surgery at 5 standard points. Then statistical tests were performed. The results are as bellow:Average of change in corneal thickness were: Central point 10.96±13.8 micron (2%); Superior point 6.82±29.8 micron (1.34%); Inferior point 9.01±28.8 micron (1.77%); Temporal point 12.1±26.4 micron (2.34%); Nasal point 5.14±34.4 micron (1.13%) Therefore corneal thickness was increased after RK surgery and it is important in repeated surgery for eye surgeon. These changes in corneal thickness at 5 standard points are related to sex with a confidence of level of 95% and in females were more. The changes of corneal thickness at 5 standard points are related to age and interval of operation with a confidence of 35%.