Abstract
Purpose :
To analyze retinal sensitivity (RS) over macular areas affected by fibrosis in neovascular age-related macular degeneration (nAMD) using microperimetry
Methods :
Observational, cross-sectional study including 40 eyes (40 patients,21 females) affected by inactive scar lesions due to nAMD.
Patients underwent visual acuity(VA), mesopic and dual-color scotopic microperimetry centered on the scar(MAIA-S; CenterVue),color fundus photography(CFP), optical coherence tomography (OCT) and blue autofluorescence (BAF).
To measure RS, Infrared images provided by S-MAIA and CFPs were imported in ImageJ and co-registered: the average of sensitivity values within the involved area was calculated.
Scars were graded as fibrotic or non-fibrotic on CFP as described by CATT study and subdivided based on the OCT classification proposed by Souied: underneath retinal pigment epithelium (type A, sub-RPE), mixed sub-retinal and sub-RPE (type B) and purely subretinal (type C). Outer retinal layers’ (ORL) status, pseudodrusen, central subfield thickness and subfoveal choroidal thickness (SCT) were evaluated on OCT.
Results :
Mean age of our cohort was 76.7±8.7 years.
Overall, 14 lesions(35%) were graded as non-fibrotic and 26 as fibrotic(65%).
Eyes with non-fibrotic lesions had better VA (p=0.002) and higher mesopic and red scotopic RS(p<0.001).
Based on OCT, 14 eyes had fibrovascular scars without fibrosis(35%), 8 had type A fibrosis(20%), 6 type B(15%) and 12 type C(30%).
Eyes without fibrosis or with type A fibrosis showed better VA and higher mesopic and red scotopic RS compared with eyes affected by type B-C fibrosis (p<0.001). No significant differences were found for cyan scotopic RS(all p>0.05).
On multivariate analysis, mesopic and red scotopic RS were negatively associated with fibrosis and rarefaction of ORL on OCT (p<0.05), while cyan scotopic RS was meaningfully affected by reduced SCT and ORL rarefaction(p<0.05).
Conclusions :
VA has limitations as functional endopoint in AMD: our study is the first to assess macular function with microperimetry over areas affected by scars.
Our results confirm that eyes with sub-RPE fibrosis(type A) maintain better functional outcomes under mesopic conditions compared with subretinal ones(type B-C). The lack of significance under cyan scotopic conditions suggests a preferential rod impairment over neovascular membranes or might be due to a floor effect exerted by the underlying AMD affection.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.