Abstract
Purpose:
To investigate the prevalence and relationships of peripheral vasculitis, ischemia, and vascular leakage in uveitis using ultra widefield fluorescein angiography (uwFA).
Methods:
Consecutive uwFA images were collected from patients with uveitis over a 12-month period. The extent of peripheral vasculitis, capillary non perfusion and leakage were quantified. Parameters quantified included (1) vasculitis- the length of vascular segment affected, (2) capillary non perfusion- foveal avascular zone (FAZ) area, peripheral ischemic index, and (3) peripheral vascular index from (i) “diffuse leakage” i.e. from existing retinal arteries, veins and capillaries, or (ii) leakage from neovascularisation. Optical coherence tomography scans at the foveal centre subfield were used to derive central macular thickness (CMT).
Results:
82 eyes from 82 patients were included. 38 (46.3%) had a diagnosis of idiopathic uveitis, 26 (31.7%) tuberculosis, 7 (8.5%) sarcoidosis, and the remaining 11 (13.4%) from other causes. 29/82 (35.4%) of patients had peripheral ischemia, 38/82 (46.3%) peripheral leakage, and 24/82 (29.3%) peripheral vasculitis. In all patients, the extent of peripheral ischemia was correlated to CMT (r=0.37, p=0.006) and the peripheral vasculitis index (r=0.45, p=0.0001). An association was also observed between the peripheral vasculitis index and CMT (r=0.30, p=0.03). No relationships were observed between peripheral ischemia and leakage. Stepwise multiple regression analysis revealed that a poor visual acuity was independently associated with peripheral ischemia and FAZ size (R2-adjusted=0.41, p=0.0001) but not with CMT, peripheral leakage or vasculitis.
Conclusions:
The relationships between peripheral vascular pathology and visual function in uveitis are not well understood. We present the largest reported cohort of patients with uveitis, imaged using uwFA and describe novel methods for characterization of peripheral vascular pathology, in an attempt to identify visually significant parameters, not possible with conventional fluorescein angiography.
Keywords: 550 imaging/image analysis: clinical •
746 uveitis-clinical/animal model •
464 clinical (human) or epidemiologic studies: risk factor assessment