Variation on the Anterior Segment Parameters after Dilatation as Measured by Sirius Tomogram in the Young Indian Population

Introduction: Evaluating corneal parameters is crucial for understanding corneal diseases and ensuring accurate screening and monitoring in refractive surgeries. Precise corneal measurements are requisite for a good refractive surgery outcome. We routinely perform pupil dilatation (mydriasis) during comprehensive ophthalmological examination. Understanding the impact of dilating eye drops on corneal parameters is crucial for individuals planning refractive surgeries. Moreover, miscalculation of corneal parameters changes after dilatation might negatively impact the desired results after refractive procedures. Purpose: The cornea plays an important role in the precise focus of light onto the retina, facilitating the perception of clear vision. Numerous factors influence the corneal biomechanics, including the instillation of various topical eye drops. This study tries to explore the potential effects of dilating eye drops on corneal parameters. Methods: This cross-sectional analytical study included 55 young, healthy individuals (age 17–25 years) reporting to a boarding center for the medical examinations of different streams from June 2023 to August 2023. The sample size was calculated considering the last 3 years’ average number of candidates reporting for the examination, pre–posttest minimum central corneal thickness (CCT) values from the literature, and paired t -test for the hypothesis with a 95% confidence interval and power of the order of 0.8. All candidates underwent a detailed ophthalmological examination. The corneal tomogram was done using the Sirius (CSO Florence, Italy) machine under dim light, and pre- and postdilatation of four corneal parameters were recorded (CCT, higher-order aberrations (HOAs) at 2 mm 3 and 3 mm 3 , and corneal volume). Results: On the evaluation of pre- and postmydriatic values, it was observed that the CCT (min) and HOA (2 mm 3 ) increased significantly postmydriasis ( P < 0.001 and 0.02, respectively). The effect of the mydriatic on corneal volume and HOA (3 mm 3 ) was not found to be significantly different among pre- and postmydriatic values. Conclusion: This study emphasizes the role of dilating eye drops in increasing corneal thickness and corneal aberrations significantly, as measured by the Sirius tomogram, which plays a crucial role in planning various refractive procedures.