Dose Response in the Subthreshold Nanosecond Laser Trial in Early Stages of AMD: A LEAD Study Report

To examine the association between treatment parameters and the progression to late age-related macular degeneration (AMD) in the Laser Intervention in Early Stages of Age-Related Macular Degeneration (LEAD) study, a randomized, controlled trial of a subthreshold nanosecond laser (SNL) for slowing disease progression in the early stages of AMD.

The association between treatment parameters early in the trial period for participants in the SNL arm of the LEAD study and time to develop late AMD during the 3-year trial duration was examined. Parameters included treatment energy at the baseline and 6-month visits and the number of laser spots visible on fundus autofluorescence (FAF) imaging taken at 6 and 12 months (taken as a proxy measure of early, adequate delivery of the laser treatment at the baseline and 6-month visits, respectively).

A multivariable analysis revealed there were no significant associations between time to develop late AMD and number of FAF-visible laser spots at 6-months (adjusted P = .537) nor laser energy used at baseline (adjusted P = .910). No significant associations were also observed when evaluating FAF-visible spots at 12-months (adjusted P = .107) and the average laser energy used at baseline and 6 months (adjusted P = .558).

This study did not find any evidence to suggest that there was a dose response for the effect of laser treatment using these treatment parameters on the progression of AMD. [.