The role of optical coherence tomography in Alzheimer’s disease

Abstract

BackgroundAlzheimer’s disease (AD) is the most common cause of dementia and its incidence is increasing worldwide along with population aging. Previous clinical and histologic studies suggest that the neurodegenerative process, which affects the brain, may also affect the retina of AD patients.Main bodyOptical coherence tomography (OCT) is a non-invasive technology that acquires cross-sectional images of retinal structures allowing neural fundus integrity assessment. Several previous studies demonstrated that both peripapillary retinal nerve fiber layer and macular thickness measurements assessed by OCT were able to detect neuronal loss in AD. Moreover, recent advances in OCT technology, have allowed substantial enhancement in ultrastructural evaluation of the macula, enabling the assessment not only of full-thickness retinal measurements but also of inner retinal layers, which seems to be a promising approach, mainly regarding the assessment of retinal ganglion cell layer impairment in AD patients. Furthermore, retinal neuronal loss seems to correlate with cognitive impairment in AD, reinforcing the promising role of OCT in the clinical evaluation of these patients.ConclusionThe purpose of this article is to review the main findings on OCT in AD patients, to discuss the role of this important diagnostic tool in these patients and how OCT technology may be useful in understanding morphological retinal changes in AD.

Evaluation of optical coherence tomography angiographic findings in Alzheimer’s type dementia

“…As the severity of cognitive impairment can be measured with MMSE score, the association between the OCT parameters and this cognitive test can give us useful information for the clinical valuation and monitoring of patients with ATD 25. In our study, we found a significantly higher positive correlation between the MMSE score and superficial retinal vascular density and CT.…”

Optical Coherence Tomography in Alzheimer’s Disease and Other Neurodegenerative Diseases

“…Converging data on AD-related retinal abnormalities encouraged investigators to develop noninvasive retinal imaging modalities in order to detect and measure these anatomical changes in living patients. This was initially attempted using blue-light high-resolution photography by Tsai et al ( 63 ), and later advanced to utilizing cross-sectional imaging by OCT ( 34 , 37 , 67 – 70 ). OCT findings in MCI, AD, and PD patients along with their correlations with cognition and vision are described subsequently and summarized in Tables 1 and 2 .…”

Optical coherence tomography in the investigation of systemic neurologic disease

“…In addition to the above findings, studies have demonstrated a link between OCT measures and psychological tests, such as the mini‐mental state examination, that are utilised to assess cognitive function . The retinal nerve fibre layer and macular parameters have been shown to be correlated with mini‐mental state examination scores.…”