Optical coherence tomography of the vitreomacular interface in photodynamic therapy
- Correspondence to: Jay S Duker New England Eye Center, Tufts-New England Medical Center, Tufts University, Boston, MA, USA; jdukertufts-nemc.org
- Accepted 14 March 2005
We would like to comment on the excellent article by Sahni et al.1 In their paper, a number of descriptive terms for optical coherence tomography (OCT) analysis are defined in patients with age related macular degeneration (AMD) with subfoveal choroidal neovascularisation undergoing treatment with photodynamic therapy. One term, “vitreomacular hyaloid attachment (VMHA),” was used to refer to incomplete separation of the posterior hyaloid with attachment at the macula. Twenty of 56 patients (35.7%) included in the study had VMHA on OCT. We would like to point out that this vitreomacular configuration is identical to that described in a previous report of normal eyes.2
The study by Uchino et al reported OCT findings at the vitreoretinal interface in 209 normal eyes. In their study, they defined five individual stages of posterior vitreous detachment (PVD). Two stages represented partial PVD with persistent macular attachment, identical to VMHA as defined by Sahni et al. Stage 1 was defined as focal perifoveal PVD in one to three quadrants with persistent vitreofoveal attachment, and stage 2 was defined as perifoveal PVD in all four quadrants with persistent vitreofoveal attachment. Of the 209 normal eyes, 47.8% had stage 1 PVD and 12.6% had stage 2 PVD. Mean age of the patients in the study was 52.3 years (range 31–74 years).2
We find it interesting that the percentage of AMD patients with VMHA in the Sahni study is less than the percentage of normal eyes with stage 1 or 2 PVD in the Uchino study.1,2 This suggests that the vitreomacular configuration defined as VMHA by Sahni et al is probably not a finding specific to the AMD patients included in the study.
Author’s reply
We thank Mennel et al and Duker and Witkin for their interesting comments regarding our article.
Mennel et al make some interesting points on the immediate structural changes that occur after photodynamic therapy (PDT), a topic that we thought was outside the scope of our study. I agree that the short term and long term changes after treatment are important and need to be taken into account in future studies on patients undergoing PDT.
We are grateful to Duker and Witkin for pointing out the article by Uchino and colleagues.1 Our patients were older (mean 76 years (range 59–94)) than those reported by these authors (mean 52.3 years). Uchino et al had 20 patients in the same age group and only two patients were above 70 years of age. Both these had a complete posterior vitreous detachment (PVD). All our patients had associated pathology and the majority had undergone PDT, all of which may have influenced the outcome. While the finding of vitreomacular attachment may be more common in normal eyes (>50%), our study2 suggests that the incidence may be may be lower in patients with exudative age related macular degeneration (35.7%).
