Optic nerve head curvature flattening is associated with central visual field scotoma (blind area)

Myopia (near-sightedness) is a highly frequent eye disease, especially in Asia, and is a well-known risk factor for glaucoma. Myopia is characterized by structural changes, including changes in the optic nerve head (ONH) caused by the elongation of the eyeball, which are thought to contribute a lot of stress on the eyes and increase the risk of glaucoma. (The optic nerve head is the circular area in the back of the inside of the eye where the optic nerve connects to the retina.)  ONH tilting is one of the most frequently observed morphological changes in myopia, but current methods for measuring ONH tilt have drawbacks.

This study aimed to develop a new index of the average curvature ratio (ACR) to represent optic nerve head tilting and investigate its clinical relevance. 231 and 144 myopic eyes were included in the flat and convex ONH groups, respectively.

The researchers found that central scotoma occurred more frequently in the flat ONH group. Peripheral scotoma was not significantly different between the groups. In the correlation analysis, the ACR was positively correlated with spherical equivalence (an estimate of your eye’s refractive error), but not with axial length (measure of front to back of the eye) or central corneal thickness (a parameter used in assessing potential glaucoma patients). The authors conclude that ACR reflects the degree of ONH tilt and is a good index for estimating central visual field damage in myopic eyes.

Source: J Clin Med. 2024 Jan 19;13(2):596. doi: 10.3390/jcm13020596