Purpose: : To evaluate the long-term natural course of macular telangiectasia Type 2, correlation with visual acuity and the incidence of Choroidal Neovascularisation (CNV) in Indian eyes.
Material and methods: : A Retrospective analysis of Patients with MacTel Type 2 was done over a period of 12 years with all patients having a minimum of 3 years follow up. The demographic details and ocular characteristics including best-corrected visual acuity (BCVA), fundus photography, fluorescein angiography, and optical coherence tomography images were studied in both proliferative and non-proliferative MacTel. Mixed models were used to estimate progression rates and a Kaplan Meier estimation of BCVA was plotted.
Results: : Eighty-two eyes of 47 patients were studied over a period of mean duration of 4.5 years (range: 3 years-8.5 years). There was no difference in the demographic characteristics between the non-proliferative MacTel and proliferative MacTel groups. There were no significant risk factors observed for progression. However, patients with retinal greying had significant risk reduction for a BCVA decline. The mean logMAR BCVA decreased from 0.25 ± 0.25 at baseline to 0.46 ± 0.42 by 4 years. Twenty-eight percent of the patients maintained their vision 8 years from baseline and were unlikely to progress. The incidence of CNV was 10.6% and the mean duration for the development of CNV was 2.36 years from baseline. Seventy-Three percent (11 of 15) patients with CNV had a BCVA of <20/40.
Conclusion: : In patients of MacTel, the maximum vision loss occurred at the fourth year and then stabilized. The major cause of poor vision observed was CNV (active in 10.98% and scarred in 7.32%), foveal atrophy (10.98%) and central pigmented plaques (3.66%). The incidence of sight-threatening complication of CNV (10.6%) is likely to occur only in a minority of eyes.
Keywords: Disease progression; Indian eyes; MacTel type 2; Natural history; Visual acuity; choroidal Neovascularization; neovascularization.