Résumé
Purpose: To compare the efficacy of Kane formula with Sanders Retzlaff Kraff/Theoretical (SRK/T) and Barrett Universal II in predicting intraocular lens (IOL) power in Indian eyes. Methods: This retrospective study conducted in a tertiary care eye hospital. Data from patients having uneventful cataract surgery with Tecnis ZCB00 IOL implantation were obtained from Lenstar and electronic medical records. Eyes were divided into subgroups based on axial length (AL) as short (<22.0 mm), medium (22� mm), and long (>24 mm). The predicted refractive outcome for each patient was calculated after optimizing the lens constant. Prediction error was calculated by subtracting the predicted spherical equivalent from achieved spherical equivalent 1 week post?surgery. The mean absolute error (MAE) and median absolute error (MedAE) and percentage of eyes within 0.25, 0.5, 1, and 2 D were calculated for each formula. Friedman test, Cochrane Q test were used for statistical analysis. Results: Out of the 350 eyes included in the study, we found that without lens constant optimization, Barrett formula performed better than SRK/T and Kane (P < 0.0001). Over the entire range of axial lengths, Kane formula performed slightly inferior compared to Barrett and SRK?T, both of which performed equally well (P = 0.006). On subgroup analysis, Kane formula performed inferiorly for medium eyes as compared to the other two. No significant differences were noted between the formulae for short and long eyes. Conclusion: Kane formula did not outperform Barrett Universal II and SRK/T in Indian eyes
Résumé
Background: Nonmydriatic digital imaging (NMDI) is ideal for screening diabetic retinopathy (DR), but its use in Indian eyes has not been evaluated. Aim: The aim was to evaluate the sensitivity and specifi city of NMDI as a screening tool in detecting DR in Indian eyes. Design: A prospective, nonrandomized, noncomparative, noninterventional study. Materials and Methods: A total of 500 diabetic patients visiting the endocrinology clinic (September 2008-June 2010) underwent NMDI (Zeiss Procam), followed by routine dilated fundus photography (FP; Zeiss Visupac 450+) of 345° retinal fi elds (1) optic disc and macula, (2) superotemporal, and (3) nasal to optic disc. Two-masked retina specialists graded the images for quality and severity of DR, and compared between NMDI and dilated FP. Statistical Analysis: SPSS Windows 17 for version. Results: Mean age was 52.97 ± 13.46 years (306 males: 194 females). The rate of ungradable images was 30.6% and 31% by the two observers. By observer 1, the sensitivity and specifi city of detecting any DR was 58.8% and 69.1%, respectively, ( = 0.608) and sight-threatening DR (STDR) was 63.1% and 68.9%, respectively, ( = 0.641). By observer 2, the sensitivity and specifi city was 57.3% and 68.3%, respectively, for any DR ( = 0.593) and 62.8% and 68.3%, respectively, for STDR ( = 0.637). The level of agreement between two observers was high ( = 0.96). Conclusion: A high rate of poor quality photographs and low sensitivity limited the use of NMDI as a perfect screening system, particularly in dark iris population with diabetes as seen in Indian eyes.
Résumé
The purpose of this study was to measure peripapillary retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography (SD-OCT) in normal Indian eyes, for which, 210 normal volunteers were recruited. One eye of each subject underwent RNFL scanning at 3.4 mm circle diameter around optic nerve using SD OCT. The data were analyzed to determine RNFLT in the sample population and its variation with age and gender. The average peripapillary RNFLT was 114.03 ± 9.59 μm. There was no effect of gender on RNFLT parameters. Age had significant negative correlation with average (P = 0.005), superior (P = 0.04), temporal (P = 0.049), and nasal quadrants (P = 0.01) RNFLT. Inferior quadrant RNFLT also had a negative correlation with age, but it was not statistically significant (P = 0.15).
Résumé
Purpose: The aim was to study optic nerve head (ONH) parameters in normal Indian eyes using spectral domain optical coherence tomography (OCT)/scanning laser ophthamoscope (SLO). Materials and Methods: One hundred and fifty-seven eyes of 157 normal subjects of various age groups underwent ONH imaging with spectral OCT/SLO and the parameters obtained were correlated with disc size. The effect of age, gender, and refractive error on various ONH parameters were also studied. Results: The mean optic disc area was 3.36 ± 0.64 mm2 (range, 2.13–5.08 mm2), mean rim area was 2.49 ± 0.58 mm2 (range, 1.20–3.62 mm2), and mean cup area was 1.10 ± 0.75 mm2 (range, 0–3.07 mm2). The disc area showed significant positive correlation with the rim area, cup area, horizontal cup disc ratio, vertical cup disc ratio, cup disc area ratio, mean cup depth, and maximum cup depth (P < 0.001). Neither gender nor refractive error showed any significant difference in various ONH parameters. ONH parameters did not show significant change with age except for rim area which declined with the advancing age (r = –0.25, P < 0.001). Conclusions: The quantitative measurement of ONH topography obtained with this study provides a normative database for an Indian population with spectral OCT/SLO. As optic disc area influences ONH topography, disc size should to be considered when evaluating optic disc for progressive optic neuropathies such as glaucoma.