Abstract
Purpose :
The area of a toxoplasmic scar in the fundus is one of the main factors defining its prognosis, especially when the lesion is in the macular area. Our goal was to assess the ratio of scarred/active areas of fundus lesions in patients with presumed ocular toxoplasmosis.
Methods :
This was a retrospective monocentric study of patients with presumed ocular toxoplasmosis seen between May 2004 and February 2018. The diagnosis was made in the presence of characteristic fundus lesions in patients with a positive anti-Toxoplasma serology. Cases with images of baseline active as well as scarred lesions of the fundus were included. The borders of each active or scarred lesion were delineated on color photographs by two masked observers and the area of the lesions was calculated using Digimizer 4.2.2 (MedCalc Software, Ostend, Belgium). The interobserver variability of the measures was recorded and the means of the measures assessed by each observer were used for further calculations. For every case, the ratio of the area of scarred retinochoroiditis over the area of the baseline active lesion (R) was calculated. Factors that could have influenced this ratio were analyzed using Wilcoxon sum rank test and a multivariate linear regression.
Results :
171 cases (83 males and 88 females) with a mean age of 31.6 ± 13.8 years were included. The median time between the measures of the active and the scarred areas was 85 [38-361] days. The average areas of active and scarred retinochoroiditis were respectively 1.32 ± 1.59 and 1.79 ± 2.36 optic disc area. Interobserver reliability was high (Intraclass correlation coefficient 0.92 [range 0.89; 0.96]). There was a strong correlation between active and scarred areas of retinochoroiditis (Linear correlation - Pearson coefficient 0.89 [range 0.85 - 0.92]). The average ratio between scarred and active areas of retinochoroiditis was 1.36 [range 0.54 - 2.18]. The administration of a systemic treatment [R=1.25, p=0.003], the absence of a pre-existing scar [R=1.05, p<0.001] and a peripapillary location of the lesion [R=0.85, p<0.001] were each significantly associated with smaller scarred/active area ratios.
Conclusions :
We assessed in a reproducible manner the ratio of scarred/active areas of toxoplasmic lesions. Our results showed that the area of scarred lesions was on average slightly larger than the area of active retinochoroiditis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.