A PDR reactive to eye closure first appears at what age range?

A PDR (Pupillary Light Reflex) that is reactive to eye closure typically emerges between the ages of 3 to 6 months. At this stage, the central nervous system is developing, and the pathways that facilitate reflex responses are becoming functional. This development allows infants to begin demonstrating the ability to respond to light stimuli through pupil constriction when one eye is closed. By about six months, several visual and reflexive responses are becoming more coordinated, indicating maturation of both sensory and motor pathways.

In other age ranges, reflexive responses are developing but not specifically reactive to eye closure. For instance, infants younger than 3 months often exhibit a basic pupillary reaction to light, but this is not specifically tied to the eye-closing mechanism. By the time children reach 1-2 years, these reflexes are usually well-established and may appear more sophisticated, thus falling outside the range of initial emergence. The focus on the critical developmental milestones helps to clarify why 3 to 6 months is the correct age range for the first appearance of a PDR reactive to eye closure.