Visual function and macular architecture in patients with inactive zone 2 and 3 toxoplasmic retinochoroiditis

To evaluate the visual function and architecture of the central and peripapillary retina in patients with inactive toxoplasmic retinochoroiditis outside the macular and peripapillary regions (zones 2 and 3).

Cross-sectional study of 20 eyes (18 patients) with zone 2 and 3 toxoplasmic scars and visual acuity ≥20/25. Patients underwent Humphrey 10-2 perimetry, contrast sensitivity (Mars test), and color vision testing (L'Anthony desaturated D-15). The retinal nerve fiber layer (RNFL) and macular thicknesses were determined by optical coherence tomography.

The patients' mean age was 27.4 ± 10.3 years, and the mean duration of remission was 6.15 ± 5.19 months. Abnormal contrast sensitivity and color vision were observed in three (15.0%) and four eyes (20.0%), respectively. Mean deviation (MD) and pattern standard deviation (PSD) fell outside the 95% normal confidence limits of the perimeter's database in 14 (70.0%) and seven eyes (35.0%), respectively. Foveal and mean RNFL thicknesses were within the normal limits in all eyes. Eyes with zone 2 retinochoroiditis had lower foveal sensitivity than eyes with zone 3 lesions (p=0.041). Eyes with a longer duration of remission had a higher MD (r=0.575; p=0.013) and a lower PSD (r=-0.593; p=0.010).

Despite normal central and peripapillary retinal architecture, eyes with inactive zone 2 and 3 toxoplasmic retinochoroiditis can present with abnormal color, contrast, and macular perimetric sensitivity. Zone 2 retinochoroiditis was associated with lower foveal sensitivity, and a longer duration of retinochoroiditis remission was associated with better perimetric parameters (MD and PSD).