There is little firm information on the natural history and visual outcome of the disease in literature. All of the reported cases have limitations, such as small sample size, adopting therapeutic regimens that have limited scientific validity, narrow period of follow-up and personal biases. Several features have been reported about IRVAN, including an association with fungal sinusitis, initial presentation as optic disc oedema with elevated intracranial hypertension and a rapid change in the dynamics of the aneurysms
Over the years, many therapeutic regimens have been evaluated. The main treatments can be divided into three categories: (1) medical, (2) surgical and (3) photocoagulation which includes PRP, focal laser on leaking macroaneurysms and grid laser photocoagulation for macular oedema.
The presence of the anterior chamber and vitreous cells as well as the rapid change in the morphological appearance and location of the aneurysms could be the result of a migratory inflammatory process involving the alternate segments along the vascular tree
. However, therapeutic response to steroids is absent or minimal
[1, 2, 5, 8, 10]. In the quest of better alternatives to steroids, antitumor necrosis factor agent therapy has been appraised with promising results
Vitrectomy has been used in the presence of vitreous haemorrhage and in conjunction to PRP in an attempt to improve visual outcome
. Recently, a case report has been published regarding the use of intravitreal ranibizumab treatment combined with PRP and vitrectomy
PRP has been suggested as the treatment of choice for IRVAN in the presence of widespread retinal ischemia so as to prevent the development of ocular neovascularization and vitreous haemorrhage
. The rationale for this therapeutic approach was based on the results of the Diabetic Retinopathy Study and the Central Vein Occlusion (CRVO) Study, which recommended argon laser PRP in high risk proliferative diabetic retinopathy and CRVO with iris neovascularisation respectively
[11, 12]. According to both studies, the presence of retinal or iris neovascularisation was a prerequisite for the initiation of PRP. However, Samuel et al. state that visual prognosis may depend on the early initiation of treatment with PRP for extensive ischemic retinal disease, even without the presence of neovascularization
. The extent of retinal non-perfusion though was not quantified.
In our case series, all eyes that were treated with PRP, irrelevant to the extent of retinal non-perfusion, maintained excellent VA and demonstrated no progression of retinal ischemia. Two eyes at stage 2, which exhibited retinal ischemia in less than two quadrants, were treated only with grid laser for macular oedema and focal laser on the macroaneurysms. VA improved by two lines of the Snellen chart, and there was no progression of retinal ischemia during the 3 and 4 years of follow-up period of these eyes (Figures
2I). One eye of stage 1 was not treated and the clinical picture remained stable.
Exudative maculopathy was responsible for the initial decrease in vision in the seven eyes of the review by Samuel et al. and in the five eyes of our patients. After application of grid/focal photocoagulation, two thirds of the eyes of the review maintained a VA within one line of the initial VA and all of our patients improved their VA by one or two Snellen lines. Direct photocoagulation to leaking macroaneurysms has been opposed due to the occlusion of the blood vessel originating at the site of the vessel burn
[4, 13]. However, laser was applied on the leaking macroaneurysms temporal to the fovea. Subsequent obstruction of the arterial branch in one eye did not affect VA and successfully prevented the leaking of the dye in FA (Figure