Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results.

Purpose: To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation.

Methods: In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters.

Intraocular lens power calculation with ray tracing based on AS-OCT and adjusted axial length after myopic excimer laser surgery.

Purpose: To report the results of intraocular lens (IOL) power calculation by ray tracing in eyes with previous myopic excimer laser surgery.

Setting: G.B.

Direct refractive index retrieval from interferometry measurements.

We present an alternative numerical method to the Abel inversion technique, which can be applied to complex non-symmetrical systems. A comparison with the Abel inversion algorithm was conducted. For benchmarking, the method was applied to a synthetic trace representing a plasma waveguide characterized by a constant parabolic density profile.

Refractive error assessment: influence of different optical elements and current limits of biometric techniques.

Purpose: To identify and quantify sources of error on refractive assessment using exact ray tracing.

Methods: The Liou-Brennan eye model was used as a starting point and its parameters were varied individually within a physiological range. The contribution of each parameter to refractive error was assessed using linear regression curve fits and Gaussian error propagation analysis.