Will a patient with Accommodative Excess have a more reduced NRA or PRA?

Will a patient with Accommodative Excess have a more reduced NRA or PRA?

• A. NRA
• B. PRA
• C. Both
• D. Neither

Answer: (A)

Relative accommodation tests assess how easily a person can adjust accommodation in response to changes in lens power—relaxing it with plus lenses (NRA) and stimulating it with minus lenses (PRA). In accommodative excess, the visual system stays over-activated and has trouble relaxing accommodation. Because NRA measures the ability to relax accommodation while keeping a clear distance target, this relaxation capacity is reduced, so NRA is lowered. PRA, which measures the ability to increase accommodation with minus lenses, is less affected in accommodative excess because the primary issue isn’t the ability to accommodate more, but the tendency to over-accommodate. Therefore, a patient with accommodative excess shows a more reduced NRA.

Relative accommodation tests assess how easily a person can adjust accommodation in response to changes in lens power—relaxing it with plus lenses (NRA) and stimulating it with minus lenses (PRA). In accommodative excess, the visual system stays over-activated and has trouble relaxing accommodation. Because NRA measures the ability to relax accommodation while keeping a clear distance target, this relaxation capacity is reduced, so NRA is lowered. PRA, which measures the ability to increase accommodation with minus lenses, is less affected in accommodative excess because the primary issue isn’t the ability to accommodate more, but the tendency to over-accommodate. Therefore, a patient with accommodative excess shows a more reduced NRA.