Abstract
Purpose: :
Anti-VEGF therapies are well established as the mainstay of treating exudative (wet) AMD. They are effective in the treatment of CNV secondary to exudative AMD. Their effect however is limited by the time it takes from the development of exudative AMD to the initiation of treatment. This study aims to determine whether there are any detectable changes on SDOCT that precede the clinical diagnosis of CNV.
Methods: :
In order to assess whether pre clinical signs of CNV were observable on OCT, patients who developed CNV in their second eye whilst on treatment for their first eye were identified from the anti VEGF database. Baseline OCTs and angiograms were reviewed in this group to confirm absence of CNV in the second eyes at baseline. OCT scans of these fellow eyes, which were captured at frequent intervals prior to the onset of CNV, and before the initiation of ranibizumab therapy were retrospectively examined and qualitatively graded for changes in the RPE and neural retinal layers. Cases with and without predictive changes on OCT were determined and detailed descriptions of any changes were made.
Results: :
Out of 749 patients on ranibizumab therapy, 73 (9.7%) received bilateral therapy. Of these 19 were male and 54 female. Their mean age was 79.3 (SD±8.4) years. The most frequent scan interval was eight weeks. (Range: 2-14 weeks). 33 (45.2%) patients had bilateral CNV on first presentation. 8 out of 73 (11 %) had no detectable SDOCT changes in their second eye at baseline. The remaining patients had abnormal OCT findings at baseline, which were not regarded as neovascular at the time but slowly developed into manifest CNV. The main changes that were seen and could be indicative of exudative AMD in the fellow eyes with no detectable SDOCT changes at baseline included; changes in the micro architecture of the RPE layer, single cysts with no evidence of SRF and small non-descript pigment epithelium detachments or drusenoid RPE changes.
Conclusions: :
Few patients showed minor changes on OCT just prior to development of manifest CNV, it is unlikely that serial OCT examination would be useful in predicting the onset of CNV in these high-risk eyes.
Keywords: age-related macular degeneration • imaging/image analysis: clinical