The Minnesota Grading System of eye bank eyes for age-related macular degeneration

Abstract

Purpose: The Minnesota Grading System (MGS) is a method to evaluate human eye bank eyes and determine the level of age-related macular degeneration (AMD), by using criteria and definitions from the Age-Related Eye Disease Study (AREDS).

Methods: Donor eyes (108 pairs) from the Minnesota Lions Eye Bank were cut circumferentially at the pars plana to remove the anterior segment. A 1000 +/- 2.5-microm ruby sphere was placed on the optic nerve as a size reference. A digital, high-resolution, color macular photograph was taken through a dissecting microscope. The neurosensory retina was removed from one globe of the pair. The underlying retinal pigment epithelium was rephotographed, localizing the fovea with a proportional triangle. A grid was superimposed in the macular photographs and images were graded according to AREDS criteria. Twenty pairs were dissected bilaterally and graded for symmetry.

Results: Eighty-eight globes were graded into one of four MGS categories. Nineteen (95%) of 20 globes had symmetric grades.

Conclusions: The MGS provides a methodology to grade donor tissue from eye bank eyes to correspond to the AREDS classification system. Donor tissue may be used for subsequent molecular analysis, including genomics and proteomics.