ORIGINAL RESEARCH ARTICLE Deactivation of the rod response in retinopathy of prematurity

Abstract It is known that retinopathy of prematu-rity (ROP) alters the activation of rod photorecep-tors, but the effect of ROP on deactivation has not been investigated. We studied deactivation using an electroretinographic (ERG) paired flash procedure in 22 subjects (12 infants and 10 older subjects) with a history of preterm birth and ROP. The amplitude of the rod-isolated a-wave response to a flash presented 2–120 s after a test flash was measured, and the time at which it reached 50 % of the single flash amplitude (t50) was determined by linear interpola-tion. Deactivation results were compared to those in former preterms who never had ROP (n = 6) and term-born controls. In infants, t50 values of ROP subjects did not differ from those in subjects who never had ROP or term-born controls. Among mature ROP subjects, eight of 12 had t50 values longer than any control subject. Prolonged deacti-vation in these mature ROP subjects may indicate lack of maturation of the deactivation process (t50) or progressive compromise of retinal function with increasing age