Correlation between cognitive impairment and retinal neural loss assessed by swept‐source optical coherence tomography in patients with mild cognitive impairment

Abstract

Introduction We compared peripapillary retinal nerve fiber layer and macular thickness measurements in patients with mild cognitive impairment (MCI) and control subjects using swept‐source optical coherence tomography (SS‐OCT). We also assessed the relationship between SS‐OCT measurements and the severity of cognitive impairment. Methods Peripapillary retinal nerve fiber layer and macular thickness were measured in 23 patients and 24 control subjects using SS‐OCT. Cognitive status was assessed using the Mini‐Mental State Examination, the Montreal Cognitive Assessment, and the Pfeffer Questionnaire. Results Most inner retinal layer thickness parameters were significantly smaller in patients with MCI, especially macular ganglion cell complex thickness measurements. Mini‐Mental State Examination and Montreal Cognitive Assessment findings were significantly correlated with most macular thickness parameters. Discussion The SS‐OCT–measured inner retinal layers of patients with MCI displayed thinning, especially in the central macular area. SS‐OCT technology can provide useful information on ocular involvement patterns and holds promise as an ocular biomarker in this patient population.

Optical Coherence Tomography in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

“…Two of the five studies showed pRNFL thinning, but no changes in the GCL-IPL complex or the macular volume (subjects MCI:controls, 52:101) (25,36). In the three other studies revealing significant differences, the authors observed significant thinning of macular structures in MCI patients compared with controls, but no significant differences in the pRNFL (subjects MCI:Controls, 90:168) (30,31,40). The final two studies did not find any significant changes in either pRNFL of macular structures between MCI patients and control pRNFL (subjects MCI:controls, 36:52) (39,45).…”

“…Communication with the authors was attempted, but no clarification was possible ( 42 , 43 ). Finally, a total of 15 studies meeting inclusion criteria were evaluated and summarized ( 21 , 23 , 25 , 26 , 28 – 32 , 34 , 36 – 40 ) (see Figure 1 ). The general description and main findings of the included studies are described in Table 1 .…”

“…The countries with the highest number of publications were from the USA (4/15) and China (3/15) ( 25 , 29 , 30 , 32 , 37 – 39 ). Other studies belonged to countries in Asia, Europe, and South America ( 21 , 23 , 26 , 28 , 31 , 34 , 36 , 40 ). Overall, there were seven different diagnostic criteria used to define MCI and one study did not report the diagnostic criteria.…”

“…Twelve studies reported circumpapillary retinal nerve fiber layer (pRNFL) measures, five reported GCL-IPL measures, and one reported an outer retinal layer measure ( 21 , 23 , 25 , 26 , 28 – 32 , 38 , 39 ). Spectral-domain OCT was the most commonly used technology (10 of 15 studies), and the remainder used time-domain OCT, Almeida et al, who used frequency domain with source sweep domain ( 21 , 23 , 25 , 26 , 29 , 40 ). All of the studies used the automated segmentation technique, with Uchida et al and Lad et al also using manual segmentation as a “safety check.” Ferrari et al used an in-house-developed segmentation software for GCL-IPL complex analysis from circumpapillary scans, which is a relatively novel approach ( 36 ).…”

“…The most common report was both circumpapillary and macular scanning (approximately 46.6%), followed by circumpapillary scan alone (33.3%), and macular scan alone (20%). Macular thickness was reported by five studies (25,26,34,37,40). Macular volume was reported in five studies with some studies reporting both volume and thickness (25,26,30,32,37).…”