Abstract
Purpose: :
One feature of Macular Telangiectasia Type 2 (MacTel Type 2) is the magnitude of visual disability when compared to loss of visual acuity. The presence of intraretinal pigment migration temporal to the fovea is characteristic of the advancing disease and signals the presence of profound paracentral visual loss, the cause of visual disability. It has been postulated that Tamoxifen might play a role neuro-protection and consequently slow the progression of the disease, effects that are seen in AMD and glaucoma. The present study aims to analyse the characteristics of MacTel Type 2 patients on Tamoxifen against matched MacTel Type 2 and normal controls, using colour (CI) auto-fluorescence (AF) amd optical coherence tomography (OCT) images.
Methods: :
The MacTel Study follows 323 patients at different stages of the disease. The patients are recruited from 23 study sites from around the world and the images are graded at the Reading Centre, Moorfields Eye Hospital, London, UK. Of those recruited, 8 patients had Tamoxifen history; no patient had Tamoxifen retinopathy. Twelve MacTel patients and 14 normal controls without exposure to Tamoxifen from the same study were age, sex, gender and visual acuity matched and graded in a masked fashion.
Results: :
On CI and AF imaging, Tamoxifen patients had less pigmentary changes (12% versus 54%). On good quality OCT (signal strength over 6), there was no difference in central thickness, or temporal inner and outer thickness between the groups (as an example: temporal inner subfield 208±22µm in normal; 200±43 µm in Tamoxifen and 183±26 µm in non-Tamoxifen MacTel patients); or in the presence and size of characteristic empty spaces on OCT.
Conclusions: :
Overall, there has been no difference noted in the severity of the OCT abnormalities related to MacTel between the groups. Further research is warranted into the pigmentary findings in order to ascertain their relevance to the disease process.
Keywords: retina • neuroprotection • clinical (human) or epidemiologic studies: natural history