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Polypoidal choroidal vasculopathy in Caucasian patients with presumed age-related macular degeneration
  1. Colin S Tan1,2,
  2. Wei Kiong Ngo1,2,
  3. Kai Xiong Cheong1,
  4. Tock Han Lim1,2
  1. 1 National Healthcare Group Eye Institute, Singapore, Singapore
  2. 2 Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore
  1. Correspondence to Dr Colin S H Tan, National Healthcare Group Eye Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; Colintan_eye{at}yahoo.com.sg

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We read with interest the article by Hatz and Prünte1 describing the frequency of polypoidal choroidal vasculopathy (PCV) among Caucasian patients treated for presumed age-related macular degeneration (AMD). We wholeheartedly agree with the authors that differentiation between PCV and choroidal neovascularisation secondary to typical AMD at initial clinical presentation is important, because this distinction may alter the management decisions and influence the eventual visual outcome.

While the prevalence of PCV in this study is generally higher than those previously reported in Caucasian populations, it is possible that the frequency of PCV in this series may have been even higher if indocyanine green angiography (ICGA) had been performed at baseline. In this study, the authors included patients who were evaluated with ICGA only after receiving ≥8 ranibizumab injections. Prior to evaluation with ICGA, the patients who were eventually diagnosed with PCV had received a mean of 6.7±3.1 ranibizumab injections.1 If the number of ranibizumab injections given to the group of patients without PCV is similar, then it is possible that some of these patients may have had PCV at initial presentation, with the polyps subsequently resolving as a result of ranibizumab therapy. Although the authors correctly pointed out that combination therapy with photodynamic therapy (PDT) and antivascular endothelial growth factor (anti-VEGF) agents appears to be more effective than anti-VEGF monotherapy in the treatment of PCV, anti-VEGF monotherapy does result in polyp resolution in a proportion of patients.2 In the EVEREST (Efficacy and safety of verteporfin photodynamic therapy in combination with ranibizumab or alone versus ranibizumab monotherapy in patients with symptomatic macular polypoidal choroidal vasculopathy) study, a multicenter, randomised, controlled study comparing PDT alone or in combination with ranibizumab against ranibizumab monotherapy, complete regression of polyps at 6 months occurred in 28.6% of patients treated with ranibizumab monotherapy (mean number of injections was 5.2±1.2).3 Therefore, in the current study, it is possible that even more patients may have manifested with PCV lesions had ICGA been performed at baseline.

The prevalence of PCV among Caucasian patients manifesting with signs of AMD merits further study and will enhance our understanding of this disease. Early detection of polyps is also important because some polyps which are initially asymptomatic may suddenly develop massive submacular haemorrhage, with significant and permanent visual loss.4 ,5

The authors highlighted the crucial role of ICGA in the diagnosis of PCV. In the methodology, it was stated that ‘differentiation was possible from the pulsation of polyps that could be observed using an ICGA movie’.1 The use of ICGA video-angiography is an essential part in the imaging protocol, as it allows detection of polyp pulsation and the presence of branching vascular network, which are two of six diagnostic criteria used for PCV.4 However, it is important to point out that pulsation is not always seen in polyps. In a review of 100 patients at our institution, only 27 (27%) manifested with pulsation on ICGA. Therefore, it is also important to rely on other diagnostic criteria to determine the presence of polyps.

For clinical settings where ICGA is not routine, another useful diagnostic feature that clinicians should evaluate is the presence of orange-red nodules, or the presence of large areas of submacular haemorrhage, both of which can be seen on fundus examination or colour fundus photography.4 ,5 These features will highlight the possible presence of polyps and suggest the need for ICGA to confirm the diagnosis. Choroidal thickening seen on spectral domain optical coherence tomography may also be a useful feature, although choroidal thickness exhibits considerable variation with factors such as refractive error.6

In summary, we support the authors’ view that PCV should be detected early using ICGA because the optimal treatment for PCV is different from typical AMD.

References

Footnotes

  • Contributors CST, WKN and KXC were involved in the literature search and writing of the article. CST and THL were involved in the reviewing and approving the article.

  • Competing interests CST receives research funding from the National Healthcare Group Clinician Scientist Career Scheme Grant (CSCS/12005) and travel support from Bayer (South East Asia) Pte Ltd. THL receives travel support from Novartis, Bayer and Heidelberg Engineering.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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