New article: The components of adult astigmatism and their age-related changes


Refractive astigmatism gradually changes from with-the-rule (WTR) towards against-the-rule (ATR) with age. This work studies the underlying corneal and internal changes using the refractive and corneal biometry data 1195 healthy Caucasian subjects, expressed in power vectors. The refractive power vectors had leptokurtic distributions with a narrow peak at zero, and a broader, secondary distribution at its base, corresponding to eyes without balanced components. The distribution of vector J0 changes significantly with age, with the narrow peak progressively becoming shorter and the broad peak shifting positive from to negative values, corresponding to increased astigmatism and a shift from with-the rule towards against-the-rule. In young participants corneal and internal astigmatism partially cancel each other out. This balance between both is gradually lost after age 50, leading to larger amounts of refractive astigmatism, as well as a reorientation of the axis. Given the small amplitude of these changes, they are unlikely to have repercussions for long term stability toric cataract or refractive surgery outcomes.

Rozema JJ, Hershko S, Tassignon MJ, for, Project Gullstrand Study Group. The components of adult astigmatism and their age-related changes. Ophthalmic Physiol Opt. 2019;39:183–193.