Pilotto E, et al. - Using an integrated morpho-functional approach and quantifying biomarker of retinal macroglial activity, investigators estimated the eyes affected by unilateral geographic atrophy (GA) (and CNV in the fellow eye; U-GA group) or by bilateral GA (B-GA group) to study the pathophysiology of GA (secondary to age-related macular degeneration). They estimated 18 eyes in the U-GA group and 22 in the B-GA group. They observed not different between groups in case of retinal thicknesses (RT), GA area, best-corrected visual acuity (BCVA), contrast sensitivity, mesopic and scotopic microperimetry and multifocal electroretinography (mfERG), and microperimetry (at both background luminance). They found significantly worse low-luminance VA (LLVA) and low-luminance deficit (LLD) in the B-GA vs U-GA group. Significantly higher glial fibrillary acidic protein (GFAP) intraocular concentration was noted in the B-GA group. They suggested the key role of the thinner choroid in unilateral cases and Muller cells as well as their supported photoreceptors in bilateral cases.