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PRP remains effective

Laser therapy still has its place in PDR treatment

Dermot McGrath

Posted: Thursday, March 1, 2018

Panretinal photocoagulation (PRP) is an established, effective therapy that should be used for treatment of proliferative diabetic retinopathy (PDR), according to Michaella Goldstein MD.
“The long-term benefits and risks of treatment with anti-VEGF agents for PDR are currently unknown, whereas we have an abundance of data over many years for PRP,” Dr Goldstein told delegates attending the 17th EURETINA Congress in Barcelona.
Left untreated, PDR is a leading cause of blindness, with more than 50% of eyes with high-risk PDR experiencing severe vision loss within five years.
Although promising results have been attained in recent years with anti-VEGF treatments, adherence to follow-up is critical to success with these pharmacological agents. In the CLARITY clinical trial, 9% of participants did not complete the one-year visit, and in the DRCR.net protocols, 12% of participants did not complete the two-year visit, she said.
“PRP is typically able to be completed in two-to-four visits, which is often sufficient for a long-lasting effect and requires no additional treatment in 50% of eyes. The Protocol S study, which compared intravitreal ranibizumab injections to PRP, suggests that approximately 45% of eyes in the Anti-VEGF arm were given additional PRP during the two-year study period,” she said.
Another potential advantage of PRP is economic, pointed out Dr Goldstein, Head of the Retinal Vascular Unit at Tel Aviv Medical Centre, Israel.
“PRP is significantly more cost-effective than anti-VEGF injections and thus may be more feasible in some health systems. Furthermore, there is no risk of endophthalmitis with laser treatment and no risk of systemic exposure to anti-VEGF,” she added.
While patients treated with intravitreal ranibizumab in the Protocol S study did have better final visual outcomes, with a gain of nearly eight letters compared to a two-letter gain for the PRP-treated group, this applied only to patients with baseline diabetic macular oedema (DME), said Dr Goldstein.
“The eyes with PDR and without baseline DME showed no statistically significant difference in final visual acuity whether treated with intravitreal ranibizumab or PRP therapy,” she said.
Another study by Dogru et al. on long-term outcomes in PDR patients after PRP treatment showed that complete regression could be successfully achieved and well preserved after 10 years.
More than 28% of patients had 20/40 or better visual acuity after five years, and most cases maintained the same visual acuity at 10 years, she noted.
“We need to bear in mind that this study was performed prior to the anti-VEGF era, and if performed nowadays the visual acuity outcomes would probably be much better by using anti-VEGF or steroid injections to treat the DME,” concluded Dr Goldstein.

Michaella Goldstein: michgold@netvision.net.il