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

Background And Objective: 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.

Patients And Methods: 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).

Results: 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 = .537) nor laser energy used at baseline (adjusted = .910). No significant associations were also observed when evaluating FAF-visible spots at 12-months (adjusted = .107) and the average laser energy used at baseline and 6 months (adjusted = .558).

Conclusions: 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. .