Abstract
Purpose :
Individuals with myopia frequently show poorer outcomes in various aspects of visual function. The underlying cause is unclear; however, reduction in retinal image quality is frequently attributed to structural and neural changes in the posterior myopic eye. Forward light scatter, which originates predominantly in the cornea and the lens, is known to produce veiling glare on the retina which in turn affects retinal image contrast. We aim to investigate whether the amount of forward light scatter varies with refractive error.
Methods :
Thirteen young-adult subjects (18-25 years), with mean spherical errors (MSE±SD, D) RE: -1.91±2.02 (range 0.38 to -4.75), LE: -1.69±1.94 (range 0.50 to -4.63) and anisometropia of ≤1.25D, underwent binocular assessment of forward light scatter using the City University AVOT test. Five glare annuli, with effective eccentricities ranging from 2 to 10 degrees, were used to estimate the parameters of the light scatter function k and n. These were then used to calculate the area under the light scatter function (k’) and the total volume of light scatter (k’’). The relationships between k’, k’’, n and MSE were examined using linear regression analyses.
Results :
A significant correlation was found between increasing myopic MSE and increase in both the integral of light scatter (k’) (RE: p<0.01, r -0.82; LE: p<0.01, r -0.81) and the total volume of light scatter (k’’) (RE: p=0.02, r -0.64; LE: p=0.01, r -0.68). There was no significant relationship found between the angular distribution of light scatter (n) and refractive error (p>0.05 for both eyes).
Conclusions :
These pilot data suggest structural changes in the crystalline lens and cornea, may play a significant role in increasing forward light scatter and hence retinal image degradation in myopic eyes. Further studies are needed to characterise such changes in the anterior media of the eye.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.