Topography-guided excimer treatment planning: Contribution of anterior corneal coma to ocular residual astigmatism

Manifest refractive astigmatism and anterior corneal astigmatism rarely agree in magnitude and axis. When expressed vectorially where RA is the refractive astigmatism and ACA is the anterior corneal astigmatism), the discrepancy between refractive astigmatism and anterior corneal astigmatism is called  ocular residual astigmatism (ORA).1 Corneal higher-order aberrations (HOAs) are thought to contribute to refractive astigmatism and therefore to ORA in highly aberrated keratoconus corneas and in irregular corneas post-laser in situ keratomileusis flap complications and excimer laser ablation–r elated complications.
Source: Journal of Cataract and Refractive Surgery - Category: Opthalmology Authors: Tags: Correspondence Source Type: research