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Half-dose verteporfin PDT increases visual acuity, reduces recurrence in central serous chorioretinopathy
COLORADO SPRINGS, Colo. — Photodynamic therapy with half-dose verteporfin significantly increased visual acuity in eyes with central serous chorioretinopathy compared with that in untreated controls, according to a study presented here.
Furthermore, recurrence was significantly less likely to occur in treated patients during the follow-up (P < .001), Timothy Y.Y. Lai, MD, said in a presentation of his thesis paper to the American Ophthalmological Society.
Timothy Y.Y. Lai
“My thesis was to look at the long-term outcome of PDT in CSC,” Lai said. The retrospective study looked at patients who were followed up for 3 or more years against an observation control group, comparing the use of PDT with half-dose verteporfin and no treatment in the controls.
The study included 192 eyes of 192 patients with mean duration of central serous chorioretinopathy of 11.2 weeks before presentation; 75 eyes were treated, and 117 eyes served as controls. Age and gender distribution between the groups was similar, as was smoking history and presence of systemic risk factors.
Mean best corrected visual acuity improved 1.8 lines and mean logMAR visual acuity improved significantly from 0.35 (20/44) to 0.17 (20/26) at last visit, Lai said. In the untreated control group, logMAR visual acuity did not change, remaining at 0.28 (20/36) with zero lines of gain in BCVA.
“In terms of recurrence, 20% of the half-dose verteporfin PDT group developed recurrence during the follow-up and there were 53% in the observation group,” Lai said. “The only factor that was significantly associated with less recurrence was use of half-dose PDT.”
As well, half-dose verteporfin PDT was the only significant factor in reducing the risk of having visual acuity of 20/40 or worse. Longer duration of symptoms before half-dose PDT treatment decreased the chance for visual acuity improvement by 4% per week of delay.
“Earlier treatment appears to improve the visual prognosis for these patients,” Lai said. – by Patricia Nale, ELS
Reference:
Lai TYY. Long-term outcome of half-dose verteporfin photodynamic therapy for the treatment of central serous chorioretinopathy: An AOS thesis. Presented at: American Ophthalmological Society meeting; May 19-22, 2016; Colorado Springs, Colo.
Disclosure: Lai reports he is a consultant for and has received grant support from Novartis Pharmaceuticals.
Perspective
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Dr. Lai discussed the efficacy of half-dose verteporfin for central serous chorioretinopathy, and when we look for level one data to support the use of this technique, the best data is probably from the randomized study by Lai and colleagues, but the cohort in this study was relatively small.
Playing devil’s advocate here, I want to raise the question, what is actually so bad about full-fluence or full-dose PDT for CSR? Dr. Lai pointed out some of the potential risks, such as secondary choroidal neovascularization, but CNV is a known complication of CSR. Does PDT truly increase the risk in this setting? The literature is not convincing on this issue. And, despite the choriocapillary ischemia and electroretinogram reductions that are seen, there did not seem to be a difference in terms of patients’ final acuity. Cases of severe persistent visual decrease are extremely rare. If the thinning of the choroid is an important mechanism by which PDT works, then maybe there would be more thinning with full-dose PDT and less recurrence than even that which Dr. Lai described. Also, if the rationale for half-dose PDT is that it may be safer than full-dose PDT, perhaps there are other approaches to increase safety, such as treatment of small regions or regions far from the foveal center, which may still cause diffuse or remote effects on the choroid.
It is exciting that there are potential treatment options for patients with CSR, but we need further randomized trials to better define the optimal therapeutic approach.