Low-fluence-rate photodynamic therapy to treat subfoveal choroidal neovascularization in pathological myopia. A study of efficacy and safety.

BACKGROUND: To evaluate the efficacy and safety of low-fluence-rate photodynamic therapy (LFPDT) to treat choroidal neovascularisation (CNV) secondary to pathological myopia (PM). METHODS: Twenty-five eyes with CNV in PM underwent LFPDT, with a standard dose of verteporfin and timing but adopting fluence and irradiance rates reduced to 25 mJ/cm2 and 300 mW/cm2, respectively. Best corrected visual acuity (BCVA) was measured and biomicroscopy and fluorescein angiography (FA) were evaluated. Particular attention was paid to choroidal hypoperfusion, and to changes (depigmentation/atrophy) at the RPE level in areas exposed to laser light. RESULTS: After a mean follow-up of 13.4+/-2.46 months (range: 12-21), and 1.37+/-0.66 treatments (range: 1-3), BCVA was stable in 29 (91%) eyes. Two (6%) patients gained more than three lines and one (3%) eye lost more than three lines. Mean greatest linear dimension did not change significantly (p=0.08) at the end of follow-up. RPE depigmentation was present in six eyes (18%) and no patient showed RPE atrophy. CONCLUSIONS: LFPDT is effective and safe for CNV secondary to PM treatment, stabilizing visual acuity and lesion size and determining only mild RPE changes. Further controlled studies are needed to demonstrate the long-term efficacy and safety of this treatment option.