Anterior, posterior, and total corneal astigmatism: clinical evidence and implications for ophthalmological practice

Cristina M. F. Carossa Veiga

Jardim

, Bárbara Santos

Rodrigues

, Alexandre Chater

Taleb

DOI: 10.37039/1982.8551.20260084

ABSTRACT

This study aimed to critically review the literature regarding the magnitude, orientation, and correlation between anterior, posterior, and total corneal astigmatism, as well as their clinical implications in normal eyes, in patients with keratoconus, and in individuals evaluated in the context of refractive surgery. An integrative literature review was conducted, with a systematic search of studies published between 2010 and 2025. Observational studies that assessed corneal astigmatism using Scheimpflug tomography in healthy eyes, eyes with keratoconus, or eyes evaluated in the preoperative refractive surgery setting were included. Twenty studies with different methodological designs were included. Of these, 12 evaluated healthy eyes, 3 evaluated eyes with keratoconus, 3 compared eyes with keratoconus and healthy eyes, and 2 involved populations assessed in the preoperative refractive surgery context. No studies were identified in post–refractive surgery populations. Consistently, anterior corneal astigmatism showed greater mean magnitude, whereas posterior corneal astigmatism, although smaller in absolute value, demonstrated clinically relevant influence on total corneal astigmatism, particularly in cases of keratoconus and oblique or against-the-rule astigmatism. Integrated evaluation of the corneal surfaces is essential for improved understanding of ocular astigmatism, greater diagnostic accuracy, and more precise surgical planning, contributing to better refractive outcomes in clinical practice.