This study enrolled fifty-five eyes with intermediate uveitis: 30 eyes from 20 patients with refractory macular edema due to intermediate uveitis (RME group), and 25 eyes from 17 patients with intermediate uveitis without macular edema (control group). Eight patients in RME group and 7 patients in control group were male (P=0.124). Averaged age of patients was 38.2 ± 7.9 (range 16-58years) in RME group versus 40.3 ± 9.4 (range 21-59 years) in control group. (P=0.753)
In refractory macular edema (RME) group underlying cause of intermediate uveitis (IU) was idiopathic in 27 eyes, Multiple Sclerosis related IU in 2 eyes and Tuberculosis related IU in one eye. In the control group, 22 eyes had idiopathic IU, 1 eye rheumatoid arthritis related IU, 1 eye sarcoidosis IU and 1 eye Tuberculosis related IU.
In the examination period, there was neither active inflammation in RME patients nor reported history of macular edema in the control group. All patients in both groups were phakic and negative for previous ocular surgery.
Vascular structure of whole image in the size of 6 × 6 mm, fovea (1.5 ×1.5 mm) and parafovea (0.5 mm circle around fovea) were analyzed in the two groups using superficial and deep layer vascular information.
Superficial layer density in RME and control group were 41.91± 5.36 vs 45.77 ± 5.55 in whole image, 17.09 ± 8.27 vs 17.93 ± 6.72 in fovea and 39.02 ± 9.75 vs 47.47 ± 6.75 in parafovea respectively. There were significant differences in superficial density of whole image and parafovea between the two groups (P=0.027, p= 0.001 respectively) however there was no significant difference between the two groups in fovea superficial density (P=0.711).
Deep layer density in the two groups were 44.78 ± 6.40 vs 45.03 ± 7.24, 32.93 ± 11.81 vs 33.04 ± 8.06, 49.95 ± 6.43 vs 51.82 ± 6.91 in whole image, fovea and parafovea respectively.
There was no significant difference in deep layer density between the two groups (P>0.05).
Cystoid space was seen in the superficial capillary plexus in all 30 eyes in the RME group and in the deep capillary plexus in 20 eyes (66%). (Figures 1 and 2)
Compared to the control group, whole image thicknesses of macula, central foveal thicknesses and parafoveal thicknesses were significantly higher in the RME group. (Table 1)
There were no significant differences between the two groups in FAZ, FAZ perimeter, acircularity index, or the foveal vessel density in 300µm-wide region around the FAZ (P>0 . 05) (Table 1 ,Figure 3).
There was no significant qualitative differences in overview images of OCT angiography print-out and vascular changes in the two groups such as capillary tuft, telangiectatic vessels or micro-aneurism.