Figure.

Changes in ERG responses as a function of age (solid line). As humans age, there is a gradual decline in ERG responses until age 55 years, followed by rapid decline until ERG responses drop to approximately 50% of that of young cohorts by age 69 years for rods and by age 70 years for cones.⁹ Shown are hypothetical ERG responses from patients with PIRDDs as a function of age, without any therapeutic interventions (squares); with one form of therapy such as gene, cell, or neurotrophic therapy (circles); or with combinational therapy (stars). @, Age-dependent critical point; #, age when PIRDDs-associated changes become prominent. This can shift depending upon the rate of degeneration.