Detection of structural and electrical disturbances in macula and optic nerve in Alzheimer’s patients and their correlation with disease severity

ABSTRACT

Aim: To evaluate and compare structural and functional changes in macula and optic nerve in Alzheimer disease (AD) patients and healthy subjects.

Methods: Both eyes of 20 AD patients and 40 age-matched healthy controls were evaluated. All subjects were evaluated by cognitive testing and comprehensive ophthalmological examination, including visual acuity, visual fields, color vision, contrast sensitivity, anterior, and posterior segment examination, optical coherence tomography, multifocal electroretinography (mfERG), and pattern-reversal visual evoked potential (pVEP).

Results: AD patients showed significantly reduced contrast sensitivity, thinner nerve fiber layer, ganglion cell layer andmacular volume. Multifocal ERG wave amplitudes were significantly reduced with delayed implicit times, which correlated significantly with the inner retinal layer thinning and poorer disease severity scores. The correlation with structural changes and disease severity was highest for pVEP, which showed significant derangement in AD patients.

Conclusion: Subclinical visual dysfunction may be present in AD patients, which may be detected as inner retinal thinning. A probable photoreceptor abnormality may also form a part of the AD disease process.

Keywords:

• Alzheimer’s
• RNFL
• GCL
• OCT
• mfERG

Authorship statement

Authors’ contributions: SS, RS, MT, DV, PS, RT, SP were involved in study design. SS, RS, MT, and DV were involved in data collection. SS and RS performed the data analyses. RS, MT, and DV provided guidance about the data analysis, interpretation, and presentation of the data. PK helped in ophthalmic investigations. All authors critically reviewed and edited the article. The authors have no funding sources to declare.

Data availability

With authors, will be made available on request.