Functional Evaluation of Retinal Pigment Epithelium and Outer Retinal Atrophy by High-Density Targeted Microperimetry Testing.

PURPOSE

Complete retinal pigment epithelium (RPE) and outer retinal atrophy (cRORA) on OCT imaging has recently been proposed to describe end-stage atrophy in age-related macular degeneration (AMD) by international consensus and expected to be associated with a , but such functional evidence is lacking. This study sought to examine the visual sensitivity defects associated with cRORA and to determine OCT features associated with deep defects.

DESIGN

Observational study.

PARTICIPANTS

Sixty eyes from 53 participants, including 342 microperimetry tests over 171 study visits.

METHODS

Participants underwent targeted high-density threshold-based microperimetry testing of atrophic lesions (with at least incomplete RPE and outer retinal atrophy [iRORA]) with a 3.5° diameter grid. The maximum extent of signs of atrophy for all lesions was graded on OCT imaging.

MAIN OUTCOME MEASURES

Number of deep visual sensitivity defects (threshold ≤ 10 decibels [dB]).

RESULTS

Presence of choroidal signal hypertransmission ≥ 500 μm, complete RPE loss ≥250 μm, and inner nuclear layer and outer plexiform layer subsidence, and hyporeflective wedge-shaped band (defined as nascent geographic atrophy [nGA]) ≥ 500 μm ( ≤ 0.020), but not RPE attenuation or disruption ( ≥ 0.192), were all independently associated with a significant increase in the number of deep visual sensitivity defects ≤ 10 dB. Only cRORA lesions with hypertransmission ≥ 500 μm or complete RPE loss ≥ 250 μm, or with both of these features ( < 0.001), but not lesions with only hypertransmission 250-499 μm ( = 0.303), had significantly more deep visual sensitivity defects ≤ 10 dB compared with iRORA lesions. Lesions with nGA ≥ 500 μm, irrespective of the presence of hypertransmission ≥ 500 μm and/or complete RPE loss ≥ 250 μm, also showed a higher number of deep visual sensitivity defects ≤ 10 dB compared with lesions without nGA ≥ 500 μm ( ≤ 0.011).

CONCLUSIONS

Not all cRORA lesions show a difference in the number of deep visual sensitivity defects compared with iRORA. Instead, hypertransmission ≥ 500 μm, complete RPE loss ≥ 250 μm, and nGA ≥ 500 μm are all OCT features independently associated with deep visual sensitivity detects that could help inform the definition of end-stage atrophy on OCT imaging.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.