Background/Aim Macular pigment optical density (MPOD) is centrally depleted early on in macular telangiectasia type 2 (MacTel). Contrast sensitivity (CS) might be related to MPOD, and thus impaired in early MacTel. The effect of low luminance was assessed on both CS and best corrected visual acuity (BCVA).
Methods This is a cross-sectional study. Pelli-Robson charts were used for CS testing at 1 m in photopic (110 lux) and mesopic (1 lux) conditions. BCVA was tested with ETDRS charts and low luminance visual acuity (LLVA) with a 2.0 log unit neutral density filter. MPOD was obtained with dual-wavelength autofluorescence.
Results One hundred and three eyes of 52 patients with MacTel (mean±SD age 62.9±10.2, range 35–77) were compared with 34 healthy eyes of 17 controls (mean±SD age 65.2±7.4, range 53–78). CS was significantly lower in the eyes with MacTel. This impairment was higher in low light conditions (low light contrast sensitivity (LL-CS)). Eyes at the early stages of MacTel had significantly lower LL-CS than controls, but normal (photopic) CS. The results were similar but less pronounced for BCVA/LLVA. Decrease in CS was correlated with loss of MPOD.
Conclusions Low light conditions have a detrimental effect on visual performance in MacTel. Impaired CS might correlate with MPOD depletion as a pathognomonic finding in MacTel. Functional impairment might precede structural disintegration, indicating dysfunction at the cellular level. The applied tests might be useful as additional functional assessments in clinical routine and as outcome measures in future interventional clinical trials.
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SMül and TFCH contributed equally.
Funding Lowy Medical Research Institute. This work was also made possible by the Victorian State Government Operational Infrastructure Support and the Australian Government's National Health and Medical Research Council (NHMRC) Independent Research Institute Infrastructure Support Scheme (IRIISS). RB was supported by the Melbourne International Research Scholarship. The funding organisation had no role in the design or conduct of this research. CAE is funded or partially funded by the National Institute of Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust, London, UK.
Competing interests None declared.
Patient consent Not required.
Ethics approval The study was conducted in accordance with the Declaration of Helsinki, and institutional review board approval (Ethikkomitee der Rheinischen Friedrich-Wilhelm Universität Bonn, Germany) has been obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent Not required.
Contributors SM and TFCH: conception and design of the work, data acquisition, analysis and interpretation of data, drafting the work and revising it critically for important intellectual content. RB: analysis and interpretation of data, critical revision of the manuscript. MF, PCI, CAE, FGH: interpretation of data, critical revision of the manuscript.
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