The anterior corneal asphericity (Q) with the tangential radius is calculated, and a three-dimensional (3-D) anterior corneal model is constructed. Tangential power maps from Orbscan II are acquired for 66 young adult subjects. The Q-value of each semimeridian in the near-horizontal region is calculated with the tangential radius. Polynomial fitting is used to model the 360-semimeridional varia...

Collagen cross-linking is gaining popularity not only for arresting the progression of keratoconus but also other indications including management of corneal infections. In this review article, we analyzed the published literature to understand the level of evidence for its use in corneal ulcer. Photoactivated riboflavin and ultraviolet A light are known to possess antimicrobial properties. The...

Purpose. To compare the characteristics of asymmetric keratoconic eyes and normal eyes by Fourier domain optical coherence tomography (OCT) corneal mapping. Methods. Retrospective corneal and epithelial thickness OCT data for 74 patients were compared in three groups of eyes: keratoconic (n = 22) and normal fellow eyes (n = 22) in patients with asymmetric keratoconus and normal eyes (n = 104) i...

PURPOSE To assess the repeatability of Equivalent Keratometry Readings (EKRs) obtained by the Pentacam HR (high resolution) in untreated and post-LASIK eyes, and to compare them with the keratometry (K) values obtained by other algorithms. METHODS In this prospective study, 100 untreated eyes and 71 post-LASIK eyes were included. In the untreated group, each eye received 3 consecutive scans u...

BACKGROUND Corneal cross-linking is widely used to treat keratoconus. However, to date, only limited data from randomized trials support its efficacy. METHODS The efficacy and safety of corneal cross-linking for halting progression of keratoconus were investigated in a prospective, randomized, blinded, placebo controlled, multicentre trial. Twenty-nine keratoconus patients were randomized in ...

PURPOSE To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP). MATERIALS AND METHODS Clinical data from 25 eyes...

PURPOSE To determine the theoretical relationships between the changes in corneal paraxial power, asphericity, and the corresponding Zernike polynomial expansion after conventional and customized excimer laser correction of hyperopia. METHODS The initial corneal profile was modeled as a conic section of apical radius of curvature R1 and asphericity Q1. The theoretical value of the postoperati...

PURPOSE To compare the final changes in corneal wavefront aberration by limbal relaxing incisions (LRIs) after cataract surgery. METHODS This prospective cumulative interventional nonrandomized case study included cataract and astigmatic patients undergoing LRIs and phaco with intraocular lens implantation. LRIs were planned using Donnenfeld nomogram. The root mean square of corneal wave aber...