Treatment frequency and visual outcome in subfoveal choroidal neovascularization related to pathologic myopia treated with photodynamic therapy

Choroidal neovascularization in pathological myopia

Myopic choroidal neovascularization (CNV) is one of the leading causes of visual impairment worldwide. The clinical and socioeconomic impact of myopic CNV in Asian countries is particularly significant due to rising trend in the prevalence and severity of pathological myopia. The exact pathogenesis of myopic CNV remains unclear and there is paucity of information with respect to incidence and risk factors for myopic CNV from prospective studies. Furthermore, there are no recognized measures that may prevent or delay the development of CNV in eyes with pathological myopia. Advances have been made in the diagnosis and characterization of myopic CNV over the years. Until recently, treatment modalities for myopic CNV were limited to thermal laser photocoagulation and photodynamic therapy with verteporfin, both these modalities primarily aim at prevention of further visual loss. In the last 5 years, inhibitors of vascular endothelial growth factor (VEGF) have been used successfully and may improve vision to some extent. Nevertheless, the long-term safety and efficacy of anti-VEGF agents remains unknown. Furthermore, the risk of developing chorioretinal atrophy remains the key factor in determining the final visual outcome. This review article summarizes the current literature on myopic CNV, highlighting new evolving diagnostic and treatment modalities, prognostic factors influencing visual outcome, and areas of future research.

Photodynamic therapy of idiopathic subfoveal choroidal neovascularization in Taiwanese patients: a 2-year follow-up

AIMS

To study the efficacy of verteporfin photodynamic therapy (VPDT) retrospectively in the treatment of idiopathic subfoveal choroidal neovascularization (ICNV) in an Asian population in correlation with number of treatments and age at treatment. This is the first report to compare the efficacy between single and multiple treatments.

METHODS

VPDT was administered according to protocol to 45 eyes in 45 patients aged 18-55 years diagnosed with active subfoveal ICNV between September 2003 and December 2005. In total 28 patients received a single VPDT treatment and the remaining 17 received multiple treatments. Collected measurements of visual acuity (VA) were plotted on a time-course model, and later dichotomized by age (18-45 vs 46-55 years).

RESULTS

The 28 patients receiving a single VPDT treatment showed significant improvement in VA at 3-month follow-up. The 17 patients, who did not show improvement after the first treatment, received multiple VPDT treatments. Those patients showed an even clearer trend in VA improvement although significance was detected only at the 24th month. All patients showed a significant improvement in mean VA of 0.46 logMAR (P<0.01 compared to baseline) by the end of the 24-month observation period, although VPDT treatment for subfoveal ICNV appears to stabilize vision more rapidly in younger patients.

CONCLUSIONS

ICNV patients who did not benefit from single VPDT treatments could receive multiple treatments, and showed a more significant improvement in visual acuity. These results are the first of their kind in ICNV treatment.