Hypertransmission and Vision in Aging and Age-Related Macular Degeneration: Longitudinal Data From ALSTAR2

To investigate the presence of hypertransmission (HT) in normal aging, early (e)AMD, and intermediate (i)AMD, changes over 3 years, and the impact of HTs ≥ 250 µm (LHyperTD) on 7 tests of scotopic, mesopic, and photopic vision.

Prospective cohort study.

Participants of the Alabama Study on Early Age-Related Macular Degeneration 2.

ALSTAR2 participants underwent spectral domain optical coherence tomography angiography (OCTA), color fundus photography, and vision testing at baseline and 3-year follow-up. HT presence and stepped diameters in choroidal en face slabs were assessed with custom review software. Only LHyperTD were analyzed at follow-up. AMD was staged via AREDS 9-step. Vision at baseline and follow-up between eyes with and without LHyperTD was analyzed with linear regression.

Presence, size, and illustrative examples of HT, association with tests of photopic, mesopic and scotopic vision.

Baseline data was available on 460 eyes of 460 patients (mean age 71.5 ± 5.7 years, 277 female; 236 normal, 134 eAMD, 90 iAMD). HT of any size were found in iAMD (86.7%), eAMD (35.1%), and normal (3.8%) eyes, with proportional LHyperTD (13.3% vs 4.2% vs 0.4%, P < .01). For 339 eyes (mean age 71.2 ± 5.8 years, 206 female, 181 normal, 92 eAMD, 66 iAMD), LHyperTD presence significantly increased in normal (P = .01) and iAMD (P < .01) but not in eAMD eyes. At baseline, photopic contrast sensitivity (CS), mesopic CS, and rod intercept time (for rod mediated dark adaptation, RMDA) were worse in eyes with LHyperTD compared to eyes without (all P < .01). At follow-up, the same were worse in LHyperTD (all P < .01), as well as low luminance visual acuity (P < .01) and scotopic light sensitivity (P = .05).

LHyperTD are rare in normal and eAMD eyes and associate with mesopic and scotopic visual functions in addition to risk-indicating RMDA. Delayed RMDA reflects other factors other than LHyperTD including differences in disease stage. Our analysis of HT < 250 µm may inform other studies of early disease. LHyperTD are best utilized as imaging biomarkers for later stages of iAMD than ALSTAR2.