Results.
For SAP, MS increased by 0.5 dB over the first year, and then showed no significant change until after year 5 (despite expected effects of aging and disease progression), after which it started to decline. For SWAP, MS of the average eye continued to improve until year 6 of the study.
Conclusions.
Our findings seem to indicate a prolonged learning effect for SWAP, with MS increasing for several years. A smaller prolonged learning effect may also be present for SAP, counteracting the effects of aging and disease progression. Deterioration of the subject's visual field may be underestimated within this period.