Table 1. Cone ERG Actuarial Table for Retinitis Pigmentosa.

Cone ERG actuarial table for patients with retinitis pigmentosa to estimate average long-term visual prognoses based on 30-Hz cone ERG amplitude at a single visit.

Expected # of Years for a Patient with a Given 30Hz Cone ERG at the Initial Visit to Decline to 0.05 μV
30Hz ERG (μV) (initial visit)	No Treatment (10% loss per year)	Vitamin A (8.3% loss per year)
0.10	6.58	8.00
0.50	21.85	26.57
1.00	28.43	34.57
2.00	35.01	42.57
2.50	37.13	45.15
3.50	40.32	49.03
5.00	43.71	53.15
8.00	48.17	58.57
10.00	50.29	61.15

Example: With no treatment, a patient age 32 with 2.0 μV at the initial visit would be expected, on average, to reach 0.05 μV in 35 years and retain useful vision until age 67 (ie., 32+35). With vitamin A treatment, this patient would be expected, on average, to reach 0.05 μV in 42.5 years and retain useful vision until age 74.5 (ie., 32+35).