Evaluation of arteriovenous crossing sheathotomy for branch retinal vein occlusion by fluorescein videoangiography and image analysis

Purpose We quantitatively evaluated the effects of arteriovenous (A/V) crossing sheathotomy on retinal circulation in patients with branch retinal vein occlusion (BRVO) accompanied by macular edema. Design Interventional case series. Methods In 18 consecutive patients (18 eyes) with BRVO accompanied by macular edema who underwent A/V crossing sheathotomy between August 1999 and April 2002, changes in retinal circulation after the surgery were evaluated by fluorescein videoangiography with a scanning laser ophthalmoscope and by image analysis using dye dilution technique. At a venule distal to the responsible A/V crossing site and a normal venule, the circulation time (T50) from the beginning of filling to 50% filling of the peak intensity was calculated. The time difference (ΔT50) between T50 at the point on the affected venule and that at the point on the normal venule, which represents the filling delay at the venule distal to the A/V crossing site, was compared between before and early after the surgery. Results The preoperative ΔT50 was 1.36 ± 1.15 seconds (mean ± SD), and the postoperative ΔT50 was 0.72 ± 0.77 seconds (P = .035, paired t test). In 11 of the 18 eyes, ΔT50 decreased by 20% or more after the surgery. In the other 7 eyes, ΔT50 was unchanged or slightly increased after the surgery. Conclusions Although a randomized controlled study is needed to confirm the effectiveness of A/V crossing sheathotomy on visual function, this technique could be effective for improving the delay in perfusion in the affected venule.