Purpose: To evaluate CORNEAL TOPOGRAPHIC CHANGES and induced CORNEAL astigmatism after scleral buckling surgery. Methods: As an interventional case series, patients referred to us from February to November 2002, with rhegmatogenous retinal detachment were scheduled for scleral buckling surgery. The exclusion criteria were: history of pervious scleral buckling, any CORNEAL disease visible on slit lamp biomicroscopy, and any ophthalmic operation in the previous 6 months. According to the extent of surgery, the patients were divided into 4 groups: A) 3600 encircling band + buckling, B) segmental buckling + encircling band, C) radial buckling, and D) local circumferential buckling. Videokeratography was done for all patients before, and then one and 3 months after scleral buckling. CORNEAL astigmatism, mean keratometry, SRI (surface regulatory index), SAl (surface asymmetry index), PVA (potential visual acuity) were evaluated at each visit. Results: From 56 patients enrolled in this study, 39 patients completed follow up. There were 29 (74.4%) males and 10 (25.6%) females with mean age of 50.35±20years. The patients consisted of 3 (7.65%) in group A, 30 (76.92%) in group B, 4 (10.25%) in group C, and 2 (10.25%) in group D. Statistically significant differences regarding SRI, SAl, PVA (in Log MAR) from baseline measurements were observed in all patients at one and 3 months postoperatively. In spite of increasing CORNEAL astigmatism, there were no statistically significant differences in mean keratometry after scleral buckling surgery. In group B, the results were the same as overall results. In groups A, C, and D the above variables were increased postoperatively. Conclusion: Irregular astigmatism is induced after scleral buckling surgery that remains up to 3 months. It is one of the important causes of decreased visual acuity postoperatively.

To investigale the TOPOGRAPHIC CHANGES in the cornea after scleral buckling and vitrectommy. A prospective study was conducted. Thses CHANGES were analyzed based on the type of surgical procedures performed. Design of this study was observational prospective case series. 49 eyes from 48 patients were stratified into four groups based on the type of surgical procedures performed. 10 underwent local buckling (group A), 9 underwent vitrectomy (group B), 18 underwent vitrectomy with encircling (group C) and 12 underwent encircling with additional segmental buckling (group D). These eyes underwent keratometry and videokeratography examinations before surgery as well as at 1, 3, and 6 months after surgery. No statistical significance was observed in the amounts of the induced CORNEAL astigmatism and the refractive cylinder among the four groups. There was statistical significance in the amount’s of the spherical equivalent among the four groups as well as based on the status of the lens(phakia and aphakia)after local buckling (group A). Statistical significance was observed in the amounts of the induced CORNEAL astigmatism before surgery and 6 months after surgery. There was statistical significance in the amounts of the spherical equivalent before surgery and 6 months after surgery among the B, C and D groups as well as based on the status of the lens (phakia and aphakia). After local or additional segmental buckling (groups A and D), CORNEAL steepening, which corresponded to the buckle occurred at a high incidence. After vitrectomy (group B) CORNEAL steepening, which correspond to the scleral sutures occurred that than changed to central steepening over time. After vitrectomy with eneircling (group C) similar CHANGES bbserved but done changed to central steepening over time such CORNEAL CHANGES persisted for up to 6 months in an irregular and asymmetric configuration. CORNEAL video keratography is a useful tool for evaluationg the post operative CORNEAL curvature. All four types of surgery were found to produce prolonged irregular and asymmetric CORNEAL shape CHANGES, where as the patterns of the CHANGES differed depending on the surgical procedures used.

Purpose: Evaluation of CORNEAL TOPOGRAPHIC CHANGES after LASIK with quantitative and qualitative methods.Materials and Methods: A semiexperimental clinical trial was done in 80 eyes of 41 patients from 1380-1382 (2001-2003) in Tabriz. In this study eyes with myopia and myopic astigmatism undergo LASIK with Nidek EC-5000.Computerized video keratography was made before, 5days after and in the last visit following LASIK with Eye sys CORNEAL analysis system and Holladay diagnostic summary programs. Findings are comparised and differences was analysed with T-test and Wilcoxon statistical methods. Results: Mean age of Patients was 30±10 (SD) Year. Mean duration of follow up was 12 months. Mean level of best corrected visual acuity before operation was 0.1 LogMar (20/25) and mean uncorrected visual acuity after operation in the last visit was 0.2 LogMar (20/30). Mean Level of best corrected visual acuity in the last visit was 0.35 LogMar (20/22).Mean amount of refractive error before operation in the spectacle plan was -5.75±3 (SD) that reached to -0.35±0.62 (SD) after operation.Mean amount of CORNEAL asphericity (Q) before operation was -0.105 (min -1.04 and max +0.35) that raised to +1.07 (min +0.01 and max +1.99) in the last visit after LASIK. Mean CORNEAL uniformity index (CUI) before operation was 97.25%, that reached to 85.37% in the last visit after LASIK.Mean predicted CORNEAL acuity (P.C.A) before operation was 20/14 that reduced to 20/25 in the last visit after LASIK.Mean decentration of CORNEAL center before and after LASIK in the horizontal axis was 0.03 mm and 0.045 mm (respectively) and in the vertical axis was 0.037mm and 0.024mm (respectively).Mean amount of effective refractive power before operation was 43.83±1.63 (SD) that reduced to 38.98±2.05 (SD) in the last visit after LASIK.TOPOGRAPHIC profiles after LASIK were: Circular (C) in 53 eyes (66.25%), circular with central bowtie (CCB) in 25 eyes (31.25%) and assymetric bowtie (ASB) in 2 eyes (2.5%).Conclusion: This study shows that LASIK with Nidek-EC 5000 causes CORNEAL TOPOGRAPHIC change from prolate to oblate with resultant correction of myopia and myopic astigmatism but, CU index and PCA are reduced after LASIK that causes unwanted effects on visual quality.

Purpose: To determine correlation between horizontal and vertical size and staging of pterygium, and CORNEAL spherical power and CORNEAL astigmatism by refraction, keratometry and CORNEAL topography.Material & Methods: 59 eyes of 44 patients were selected simply and nonrandom, in a cross sectional study. VA, staging, horizontal and vertical size of pterygium were determined and refraction, keratometry and CORNEAL topography were done. Correlation between pterygium horizontal and vertical size and staging and CORNEAL spherical power and astigmatism and VA were evaluated by Bivariate correlation tests with pearson and spearman.Results: 59 eyes of 44 patients with mean age of 49.71 years were studied. 28 patients were male and 16 patients were female. Mean of vertical size was 5.16 mm and mean of horizontal size was 3.19 mm. Correlation between horizontal and vertical size and VA (p=0.001), refraction spherical equivalent (p<0.01), average sim k (p<0.05), cu index (p<0.001), Pc acuity (p<0.001) was significant. Also significant correlation between horizontal and vertical pterygium size and refraction cyl. (p<0.00) keratometric delta k (p=0.001 and p=0.01 respectively), total astigmatism (p<0.001), delta k (p<0.001) and regular astigmatism (p<0.001)was present. No significant correlation was between staging of pterygium and refraction, keratometry and TOPOGRAPHIC parameters.Refraction astigmatism (-2.63 D), Keratometric Delta k (D) and TOPOGRAPHIC Delta k (2.20 D) was less than Total astigmatism (5.06 D) and regular astigmatism (D) on CORNEAL topography. In greater than two thirds of patients, the axis of astigmatism was with the rule.Conclusion: The greater pterygium csize, the greater effects on CORNEAL spherical power astigmatism of refraction, keratometry and topography is seen and therefore decrease in VA is greater. For decision to excise the pterygium, CORNEAL refractive CHANGES and astigmatism is better seen by topography than keratometry and refraction.

This study was performed to investigate aberrometric CHANGES of Keratoconus (KC) and its correlation with CORNEAL TOPOGRAPHIC indices. In a cross sectional study, the researchers included 170 eyes of 138 candidates that were seeking CORNEAL refractive surgery in Sohag refractive center, Sohag, Egypt and had been diagnosed as clinical KC. Patients were divided to mild, moderate, and severe KC. All eyes included in this study were subjected to CORNEAL tomographic evaluation. CORNEAL aberrometry data was collected from the Sirius topography (Sirius, Costruzione Strumenti Oftalmici, Italy) over a 5-mm diameter. The collected data included Zernike coefficients for CORNEAL aberrations, including total Root Mean Square (RMS), RMS Spherical Aberration (SA), RMS Coma, and RMS astigmatism. The study population was divided to mild, moderate, and severe KC. Mild KC cases included 58 eyes of 46 patients, moderate KC were 64 eyes of 52 patients, and severe KC were 48 eyes of 40 patients. Root mean square total was statistically significant in all groups with a higher p value in moderate KC (P = 0. 001) and also was statistically significant when compared in the three groups altogether (P = 0. 0001). Coma aberration was statistically significant in mild and moderate KC and when compared between the three groups (P = 0. 0001). Root mean square Trefoil aberration was statistically significant only in moderate KC yet was statistically significant when compared in all groups (P = 0. 0001). Root mean square astigmatism was statistically significant in mild KC only and when compared in the three groups altogether (P = 0. 0001). Spherical aberration was also statistically significant in moderate and severe KC with a P value of < 0. 0001 and 0. 001, respectively. There was a positive correlation between posterior elevation and RMS values in mild and moderate KC while there was negative or very weak positive correlation in severe KC. There were negative correlations between the thinnest location and RMS values in nearly all variables in the three groups except weak positive correlation with RMS astigmatism in mild KC and with RMS total and coma aberration in severe KC. In conclusion CORNEAL high order aberrations measured by the Sirius topography system had low to moderate correlation with CORNEAL TOPOGRAPHIC indices provided by the same device in different grades of KC...

Purpose: To study the effect of pterygium surgery on induced TOPOGRAPHIC CHANGES. Method: In 30 patients undergoing pterygium surgery, visual acuilty, CORNEAL topography, Keratometric readings and manifest refraction were recorded before and 1 month after surgery. Patients with pterygium size>3 mm were selected. Results: Successful pterygium surgery was associated with statistically significant improvement in TOPOGRAPHIC status, visual acuity, keratometry and manifest refraction. Conclusion: Surgery may eliminate all factors which induce TOPOGRAPHIC and refractive cylinder and brings about steepening in the meridian of the pterygium.

Purpose: To investigate the effect of the near visual task of movie-watching in the straight gaze position on CORNEAL TOPOGRAPHIC parameters. Methods: Thirty myopic young adults with an average age of 25.10 ± 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. CORNEAL topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis. Results: Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P > 0.130). Also, watching the movie had no effect on other CORNEAL topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P > 0.163). Conclusion: The results of the present study showed that watching movies in the straight gaze position had no effect on CORNEAL TOPOGRAPHIC parameters and did not cause errors in CORNEAL TOPOGRAPHIC measurements.

We aimed to assess age-related CHANGES in CORNEAL TOPOGRAPHIC indices, keratometry and visual acuity after sequential intraCORNEAL ring segment implantation (ICRS) and crosslinking (CXL). This was a retrospective matched case-control series including 26 eyes of patients ≤ 18 years as cases and 26 eyes of adult patients as controls. All eyes received ICRS+CXL for progressive keratoconus. Eyes were matched regarding the keratoconus parameters and the treatment (type, number and thickness of ICRS). Data was analyzed for refractive and TOPOGRAPHIC values [uncorrected and corrected distance visual acuity (UDVA; CDVA) sphere; cylinder; spherical equivalent; maximum keratometry (Kmax); flat keratometry (Kflat); steep keratometry (Ksteep); all 7 pentacam TOPOGRAPHIC indices] preoperatively and one year postoperatively. Preoperatively, there was no significant difference for any refractive, clinical or TOPOGRAPHIC parameters between the groups except for index of vertical asymmetry. After one year, children had a significantly higher improvement in Ksteep (3. 05D) than adults (2. 10D; P=0. 036) and a trend to significance for Kflat (2. 7D compared to 1. 78D, respectively; P=0. 081). UDVA improved by 4. 3 ETDRS lines in children compared to 3. 3 ETDRS lines in adults and CDVA improved by 1. 7 ETDRS lines in children compared to 1. 2 ETDRS lines in adults, but with no statistical significance. The effects on keratometry indicated that CORNEAL response after ICRS and CXL for keratoconus is more pronounced in young patients than adults. This assumption is also supported by functional improvement and by the fact that a few eyes (5) of some very young patients (<13years) showed highly remarkable improvements after surgery (higher than any adult eye)...

Purpose: To determine TOPOGRAPHIC and aberrometric CHANGES after accelerated cross-linking (ACXL; 18 mW/cm2 for 5 min) as measured with OPD Scan III (Nidek Inc., Tokyo, Japan) and their repeatability in patients with mild and moderate keratoconus (KCN). Methods: In this prospective study, 25 eyes with mild KCN [Ksteep ¼ 47. 24 ± 3. 11 diopter (D)] and 20 moderate cases (Ksteep ¼ 52. 86 ± 4. 39 D) were examined under mesopic conditions (20 lux) twice, 30e45 min apart, at baseline and 6 and 12 months afterwards. Extracted indices were Ksteep, Kflat, ocular and CORNEAL irregularity, ocular and CORNEAL total higher order aberrations (HOAs), coma, trefoil, and spherical aberration (SA). Repeatability index (RI) and intraclass correlation coefficients (ICCs) were determined. Results: In mild cases, Ksteep and CORNEAL irregularity had lower RI, but Kflat and ocular irregularity had higher RI (all P > 0. 050) at 1 year. The RI for ocular total HOAs, coma, and SA decreased and showed no significant change for trefoil (all P > 0. 050). Moderate cases showed nonsignificant increases in RI for Ksteep, Kflat, ocular and CORNEAL irregularity (all P > 0. 050), and all aberrometry indices, and significant increases in RI for ocular coma (P ¼ 0. 046) and CORNEAL trefoil (P ¼ 0. 037). At 1 year, ICC was >0. 75 for all indices except ocular and CORNEAL trefoil (ICC ¼ 0. 613 and 0. 390) in moderate cases. Conclusions: At one year after ACXL, OPD Scan III showed acceptable repeatability in mild cases. In moderate cases, TOPOGRAPHIC indices had acceptable repeatability but poorer compared to the mild group. Overall, ocular HOAs showed better repeatability than CORNEAL ones. These CHANGES should be considered in the interpretation of measurements.