Laser bypass procedure shows promise in CRVO treatments

An argon laser-based technique appears to effectively treat the underlying cause of central retinal vein occlusion (CRVO) and may lead to vision gains in a significant number of patients, Ian McAllister MBBS, Australia, told delegates at the 15th EURETINA Congress in Nice.

Laser chorioretinal anastomosis (L-CRA) works to bypass the occluded central retinal vein by creating an anastomosis between a retinal vein and the choroidal venous circulation. The laser-induced anastomosis provides an alternative route for the obstructed venous blood to exit the retinal circulation.

The rationale for L-CRA stems from the limitations of anti-VEGF treatments which essentially treat only the symptoms of CRVO and not the underlying cause, said Dr McAllister.

Studies have shown that raised venous pressure in occluded vessels can be up to 24 times the normal pressure and is a direct cause of the macular oedema in CRVO, he explained.

"Given that we know that venous pressure is a significant but as yet unaddressed component of the macular oedema in CRVO, what can we do about it? It really has been the elephant in the room for too long,” he said.

The efficacy of L-CRA has been demonstrated in the randomised Central Retinal Vein Bypass Study, said Dr McAllister. With a follow-up of 18 months, a successful L-CRA was created in 76.4 per cent of patients in the treatment group, and treated eyes that developed an L-CRA achieved an 11.7 letter-mean improvement from baseline over the control group in that same period, he said.

Recent studies looking at L-CRA treatment in combination with anti-VEGF agents also show promise as a means of producing better and more stable visual acuity with less reliance on continued intravitreal injections, concluded Dr McAllister.