Two-Year Visual Results for Older Asian Women Treated With Photodynamic Therapy or Bevacizumab for Myopic Choroidal Neovascularization

We read with interest the article by Ikuno and associates regarding the long-term visual and anatomic outcomes of treatment with photodynamic therapy or intravitreal bevacizumab for myopic choroidal neovascularization (mCNV). The authors claim that their results indicate that “intravitreal bevacizumab (IVB) provides a significantly better best-corrected visual acuity (BCVA) than photodynamic therapy (PDT).” We believe that their study has an important limitation that casts doubt on their conclusions. The beneficial findings they report appear to be mainly related to a worsening of BCVA in PDT-treated patients rather than to an improvement in IVB-treated ones. This loss of BCVA in their PDT group is not in keeping with the previously published evidence. In the discussion the authors justify this finding, stating that in the VIP study “the benefit [of PDT on mCNV] was no longer significant after 2 years.” We do not agree with this statement.

In the VIP study the visual acuity at month 24 was in favor of a benefit for eyes assigned to verteporfin ( P = .05), with a median gain of 0.2 lines in the PDT-treated group (77 subjects), compared with a loss of 1.6 lines in the placebo-treated group (36 subjects).

This is supported by all the other published studies on the efficacy of PDT for mCNV with a 2-year or longer follow-up. Chen and associates reported that in 13 patients undergoing multiple PDT treatments, visual acuity remained relatively stable with no significant differences compared with baseline for 24 months. Similarly, Pece and associates could not find any statistically significant changes ( P = .854) in BCVA at 2 years in 52 patients. In the 20 eyes receiving PDT reported by Krebs and associates, the mean value of BCVA remained nearly unchanged at month 24 compared to baseline. Lastly, in Lam and associates’ study BCVA of 22 eyes was maintained at the baseline level over a 24-month follow-up period.

The differences between the cohort of eyes studied by Ikuno and associates and the other reports in the literature could be attributable to heterogeneity of study population characteristics with different inclusion and exclusion criteria. For instance, Ikuno and associates included in their study only Japanese women aged 50 years or older and, as rightly pointed out by the same authors, certainly younger age has often been associated with less loss of BCVA. However, it should be noted that Lam and associates, in a subgroup analysis comprising Asian myopic patients older than 55 years undergoing PDT, still could not find any significant BCVA change at the end of follow-up (BCVA was 0.82 (±0.32) at baseline and 0.82 (±0.40) at month 24).

Hence the question inevitably arises: is the significant difference in the long-term visual outcome observed by Ikuno and associates between PDT and IVB generalizable to other populations of mCNV? We believe that as yet there is insufficient evidence to support the claim that bevacizumab is superior to PDT in the treatment of mCNV at least in the longer term.

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Jan 17, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Two-Year Visual Results for Older Asian Women Treated With Photodynamic Therapy or Bevacizumab for Myopic Choroidal Neovascularization

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