Refractive prediction by various intraocular lens formulas using optical biometry and effect of ocular parameters on their accuracy

Purpose: To assess the prediction accuracy of intraocular lens (IOL) formulas and study the effect of axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), and lens thickness (LT) on the accuracy of formulas using optic biometry. Methods: This study was performed on 164 eyes of 164 patients who underwent uneventful cataract surgery. Ocular biometry values were measured using Lenstar?900, and intraocular lens (IOL) power was calculated using the SRK/T, SRK II, Hoffer Q, Holladay 2, and Barrett Universal II formulas. We evaluated the extent of bias within each formula for different ocular biometric measurements and explored the relationship between the prediction error and the ocular parameters by using various IOL formulas. Results: The summarization of refractive prediction error and absolute prediction error for each IOL formulation was performed after adjusting the mean refractive error to zero. The deviation in the error values was minimum for SRK/T (0.265) followed by Holladay 2 (0.327) and Barret (0.382). Further, SRK/T had the lowest median (0.15) and mean (0.198) absolute error as compared to other formulations. For the above formulations, 100% of the eyes were in the diopter range of ±1.0. It was observed that the overall distribution of error was closer to zero for SRK/T, followed by Holladay 2 and then Barrett. Conclusion: In summary, we found that accuracy was better in SRK/T formula. We achieved a better understanding of how each variable in the formulas is relatively weighed and the influencing factors in the refraction prediction.

Medical Students' Perception about Various Methods of Learning Physiology in a Medical College in Central India

Teaching methods have huge impact over appropriate acquisition of knowledge by the intendedrecipient.Physiology course in our college is taught through lectures, laboratory sessions, tutorials, all ofwhich are teacher centered; and student-led seminars. Aim of this study was to investigate students’perceptions of the value of varying academic methods on their learning of physiology. A faculty-baseddescriptive study was conducted. 150 Pro-formas were distributed & 127 were completed. Results showedthat 108 students (85%) believed that their absence from different academic activities could affect performance.Students perceived lectures as the most valuable academic activity (90.7%), whereas seminars by studentswere perceived as least important (18.5%). There was significant correlation between lectures attendanceand performance in examinations (P-0.008). 90% students thought that teacher involvement in tutorials wasessential. These results showed that in our course, students perceived teacher involvement as a keycomponent of the learning process.