Peripapillary atrophy in patients with birdshot chorioretinitis

This study aims to analyse peripapillary atrophy (PPA), its frequency, extent and relation with measures of visual function in patients with birdshot chorioretinitis (BSCR).

Patients of the single-centre prospective COhort of patients with BIRDshot chorioretinitis (ClinicalTrials.gov Identifier: NCT05153057) were included. The areas of the optic nerve head (ONH) and PPA were measured on red-green and autofluorescence fundus images acquired by ultrawidefield retinal photography. The main outcome measure was the frequency of PPA. Correlations between the PPA/ONH ratio and disease duration, age, best corrected visual acuity (BCVA) and visual field results (mean deviation (MD) and the pattern SD (PSD)-Humphrey perimeter 30-2) were evaluated using the Spearman coefficient.

A total of 752 eyes from 384 patients (mean age 62.4±12.1 years) were included. The median disease duration was 13.0 (7.0-19.0) years. PPA was observed in 717 (95.4%) eyes. The mean PPA/ONH ratio was 2.9±2.2 on red-green images, 3.1±2.2 on autofluorescence, and these measures were highly correlated (R=0.95, p<0.0001). The ratio of PPA/ONH increased with the duration of the disease (R=0.57, p<0.0001) from 1.6±0.6 in the 0-5 years group to 5.2±2.9 after 25 years and with age (R=0.51, p<0.0001). PPA was also associated with a worse BCVA (R=-0.42, p<0.0001) and worse visual field results: MD (R=-0.41, p<0.0001), PSD (R=0.42, p<0.0001). A strong intereye symmetry of the PPA/ONH ratio was observed (R=0.91, p<0.0001), which was greater than that of BCVA (R=0.58, p<0.0001), MD (R=0.76, p<0.0001) or PSD (R=0.70, p<0.0001).

Almost all patients with BSCR exhibit PPA and its extent increases over time. PPA is associated with poorer vision.