Abstract
Purpose:
Choroidal blood flow accounts for most of the ocular blood flow and is the major source of oxygen and nutrients for the choroid and the outer retina. The choroid has also been implicated in the pathophysiology of macular oedema and retinal hypoxia. We set out to investigate the role of the choroid in retinal vein occlusion using enhanced depth optical coherence imaging (EDI-OCT). Our aim was to compare the subfoveal choroidal thickness in eyes with retinal vein occlusion with normal fellow eyes and describe changes in choroidal thickness after treatment with dexamethasone intravitreal implant (DEX implant, Allergan)
Methods:
In this pilot, longitudinal study, consecutive patients with macular oedema secondary to retinal vein occlusion were evaluated. Slit lamp biomicroscopy, spectral domain optical coherence tomography and EDI-OCT were performed at baseline in the affected and the normal fellow eye. Wide-field fluorescein angiography was also performed in all patients. 10 weeks after treatment with intravitreal dexamethasone implant, EDI-OCT was repeated in the affected eyes.
Results:
There were 10 eyes of 5 patients. 2 patients presented with branch retinal vein occlusion, 2 with hemi-vein occlusion and 1 patient with central retinal vein occlusion. Mean age was 69.8 (±13.4, range: 58-90), mean duration of symptoms at baseline was 18.8 weeks (±21.3, range: 3-52), mean axial length was 22.68 (±0.7, range:22.2-24.05) and mean best corrected visual acuity in early treatment of diabetes retinopathy study (ETDRS) letters was 48.2 (±24.6, range:17-73). In all 5 patients, the subfoveal choroidal thickness was thinner in the fellow eye compared to the normal eye (297.2µm vs 208.9µm). Additionally, 10 weeks after treatment with intravitreal DEX implant, choroidal thickness was lower compared to baseline in 3 of 5 affected eyes.
Conclusions:
EDI-OCT provides a non-invasive method of evaluating the changes in the choroid in retinal vein occlusion. Choroidal thickness was thinner in unaffected fellow eyes, compared to eyes with retinal vein occlusion. This may indicate an increase in choroidal perfusion resulting from local mechanisms compensating for the decrease in retinal blood flow. Further work is required to elucidate the role of choroidal perfusion in visual acuity and response to treatment in retinal vein occlusion
Keywords: 749 vascular occlusion/vascular occlusive disease •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
452 choroid