RETINAL ISCHAEMIA

Targeted retinal photocoagulation (TRP) seems to offer a safe and potentially less traumatic approach to the treatment of retinal ischaemia in diabetic retinopathy and venous occlusive eye diseases, according to a study presented at the 14th EURETINA Congress in London.

“TRP is an alternative approach to standard destructive pan-retinal photocoagulation in the treatment of ischaemic retinal conditions. Using integrated imaging technology with retinal eye-tracking we can deliver targeted laser treatment to the affected areas while sparing surrounding tissue,” said Igor Kozak MD, PhD, MAS.

Retinal laser photocoagulation of the posterior pole has undergone some revolutionary changes in recent years, noted Dr Kozak, with innovations such as semi-automated delivery, micropulse and selective application and the use of imaging technologies helping to improve the safety and accuracy of laser photocoagulation procedures.

Dr Kozak, a retina specialist and vitreoretinal surgeon at the King Khaled Eye Specialist Hospital, Saudi Arabia, said that TRP offers several advantages over pan-retinal laser photocoagulation (PRP), which remains the treatment of choice in numerous retinal ischaemic conditions.

“Complications of PRP even when it is well performed include laser scar expansion, worsening of macular oedema, retinal breaks and subretinal bleeding. The introduction of short-pulse pattern or sub-threshold micropulse lasers has helped somewhat to overcome these problems, but the treatments are still not as targeted as they could be when the latest imaging technology is incorporated into the procedure,” he said.

The rationale behind TRP is to direct laser photocoagulation to pathologic areas of the retina only, said Dr Kozak.

For TRP, Dr Kozak said he uses the Navilas navigated laser photocoagulator (OD-OS, Inc., Irvine, US), which integrates retinal imaging, fluorescein angiography and retinal laser in one device. Photocoagulation is executed based on previously acquired images from the same system, or imported images from another device, and the subsequent treatment plan to target the pathologic areas.

The physician prepares the treatment plan based on either angiography or fundus photos, and then overlays the plan on live retina so laser photocoagulation can follow ocular movements during treatment without contact lenses.

To test the safety and efficacy of the approach, Dr Kozak carried out a pilot case series on eight eyes of six patients with diabetic retinopathy. All pre-planned ischaemic areas were targeted by laser. Four months after treatment, just one eye needed additional photocoagulation for persistent neovascularisation while the other eyes showed no signs of proliferative disease or adverse effects from the treatment.

Dr Kozak said that navigated TRP seems to offer a viable approach to standard destructive PRP in the treatment of ischaemic retinal conditions. “The advantages include precise documentation of treatment areas with decrease in false positive and false negative laser applications,” he concluded.

Igor Kozak: ikozak@kkesh.med.sa