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N. Hunt, P. N. Dimitrov, R. H. Guymer; Abnormal Macular Function in Macular Telangiectasia. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3693.
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© ARVO (1962-2015); The Authors (2016-present)
To compare macular function with the psychophysical assessments of colour perception, flicker perception and cone and rod dynamics in adults with Macular Telangiectasia (Type II Idiopathic Juxtafoveal Telangiectasia).
The protocol was tested on 21 subjects with Macular Telangiectasia and 12 age-matched controls. In each subject contrast thresholds were measured 6° temporal to the fovea, typically where the disease starts, to evaluate visual function of the cones under steady state conditions (luminous flicker and isoluminant Red and Blue color). Adaptation dynamics of cones or rods were assessed following bleach of 30% photopigment.
The mean age of subjects with Macular Telangiectasia was 59 ± 10 years (range 46-69 years) and mean age of age-matched controls was 52 ± 14 years (range 43-76 years). Visual acuity of affected subjects ranged from 20/12.5 to 20/80 with a mean LogMAR visual acuity of 0.24, which was not significantly different between groups. Three Macular Telangiectasia subjects were diabetic with no diabetic retinopathy and one had glaucoma.In all tests there was a reduced steady state sensitivity in subjects with Macular Telangiectasia compared to the controls. Spatiotemporal: 4HZ and 14Hz, Red threshold, and Blue threshold were significantly different (p<0.001) between Macular Telangiectasia subjects and age-matched controls. Rod adaptation kinetics as derived from the RCB were significantly different between Macular Telangiectasia subjects and age-matched controls (p = 0.018).
Testing retinal function temporal to fixation in people with MacTel is feasible. The majority of subjects have abnormal results in both rod and cone function. Theses tests may be able to be used to follow the response to interventions used early in the disease.
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