Quantitative Assessment of the Retina Using OCT and Associations with Cognitive Function

Kałuz̊ny

et al. 2020

Preprint

Background Retinal imaging using optical coherence tomography (OCT) and OCT angiography (OCTA) may serve as an alternative approach to monitoring and diagnosing neurodegenerative diseases such as Alzheimer's disease (AD) and primary open-angle glaucoma (POAG). In this study, we performed direct comparisons of retinal vessel density with the thickness of inner retinal layer (IRL) and outer retinal layer (ORL) in patients with AD and POAG. Methods In this cross-sectional study, we analyzed data from 48 eyes of healthy control (HC) participants, 71 eyes of POAG patients, and 49 eyes of AD patients with confirmed presence of fibrillar brain amyloid on positron emission tomography (PET) imaging with florbetapir F 18. Ophthalmic examination included OCT imaging to measure IRL and ORL thickness in the macula and OCTA in the same region for the imaging of vessel density in the superficial vascular plexus (SVP) and deep vascular plexus (DVP) of the retina. A direct comparison of vessels density and retinal layers thickness, which different dynamic ranges, was obtained by normalizing values as percentage losses. Values were adjusted for inter-eye correlation, age, gender, and scan quality, where applicable. Results Patients with AD presented significantly greater losses of vascular density in the DVP and ORL thickness compared to POAG (p < 0.001), but percentage losses of vessel density in SVP and IRL thickness were considerable in POAG compared to AD eyes (p < 0.001). Positive associations among presence of AD were observed primarily in outer retina where a 1% decrease of ORL thickness was associated with about 24–29% increase in odds of the presence of AD. According to OCTA measurements, a 1% decrease of vessel density in DVP was positively associated with a 4–9% increase in odds of the presence of AD. In POAG positive associations among presence of disease were observed only in inner retina where 1% loss of IRL thickness and a 1% loss of vessel density in the SVP were positively associated with a 13–23% increase in risk of presence of the disease. Conclusions Analysis of ORL thickness and vessel density in DVP could potentially improve diagnostic capabilities and may provide a valuable approach for predicting of AD.

Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 84%

Quantitative Assessment of Retinal Thickness and Vessel Density Using Optical Coherence Tomography Angiography in Patients with Alzheimer’s Disease and Glaucoma

Kałuz̊ny

et al. 2020

Preprint

“…Further, neural bers and vessels were highly re ective, which interfered with OCT resolution. Therefore, we suggest that the "ganglion cell complex (GCC)" [19,20] including the RNFL, GCL, and IPL be used as a metric for retinal ganglion cell changes in rats and mice rather than the RNFL. The GCC includes all major compartments of retinal ganglion cells, while the RNFL is mainly composed of axons, the GCL of somata, and the IPL of dendrites.…”

Section: Discussionmentioning

confidence: 99%

Fundus Photography, Fundus Fluorescein Angiography, and Optical Coherence Tomography of Healthy Cynomolgus Monkey, New Zealand Rabbit, Sprague Dawley Rat, and BALB/c Mouse Retina

Xian

Zhao²,

Peng³

et al. 2020

Preprint

Background A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis. The choice of animal model is based on the measurability of specific parameters or structures, the applicability of clinical measurement technologies, and the similarity to human eye function. Studies of eye pathology usually compare optical parameters between a healthy and altered state, so accurate baseline assessments are critical, but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models. Methods Three cynomolgus monkeys, six New Zealand rabbits, ten Sprague Dawley (SD) rats, and BALB/c mice were examined by fundus photography (FP), fundus fluorescein angiography (FFA), and optical coherence tomography (OCT). Results Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP, FFA, and OCT. New Zealand rabbits have large eyeballs, but they have large optic disc and myelinated retinal nerve fibers in their retina, and the growth pattern of retinal vessels were also different to the human retina. Unlike monkeys and rabbits, the retinal vessels of SD rats and BLAB/c mice were widely distributed and clear. And the OCT preformance of them were similar with human beings. Conclusion Monkey is a good model to study changes in retinal structure associated with fundus disease, rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases, and rats and mice are good models for retinal vascular diseases. These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

“…Firstly, we assessed the cognitive function for three times in each subjects among 5-years follow-up. Previous studies concentrated on the relationship between retinal thickness and cognitive function assessed by single one-point and found close relationship between them [7,[41][42][43]. However, not all individuals with CD progressed to dementia or consistently stabilized CD, while 18%-24% of mild cognitive impairments individuals reverted to normal cognition [26,[44][45][46], which potentially leading to partial association of neurodegeneration with retinal thickness.…”

Section: Discussionmentioning

confidence: 99%

Ganglion Cell-Inner Plexiform Layer Thickness is Associated with Persistently Cognitive Decline -The Rugao Longevity and Aging Study

Zhang

Shen

Xiao-yan

et al. 2020

Preprint

Background: The simple, convenient and well-validated biomarkers are imperative for detection of cognitive decline (CD). The powerful evidence is lacked for verifying the reliability and clinical utility of retinal biomarkers for detection of CD with repeated assessments. To investigate the association of retinal thickness with CD using repeated assessments. Methods: This study included 446 older adults with three-time repeated assessments of cognitive function during 5-years follow-up. Retinal thickness measured on spectral-domain optical coherence tomography. Logistic regression models were conducted to analyze the association of retinal thickness with cognitive function. Results: According to cognitive status in three assessments, individuals were categorized into consistently normal cognition groups (N = 159), persistently CD groups (N = 134), progressed to CD groups (N = 70), and reverting or fluctuating CD groups (N = 83). Thinner ganglion cell-inner plexiform layer (GC-IPL) was associated with persistently CD (odds ratio [OR] per 1-μm decrease: 1.09, 95% confidence interval [CI], 1.02-1.18; per standard deviation [SD] decrease: 1.78, 95%CI, 1.04-3.19) rather than progressed to CD, reverting or fluctuating CD. No significant relationship was found between retinal nerve fiber layer and any CD subgroups (p > 0.05). Conclusions: Thinner GC-IPL was associated with persistently CD, suggesting retinal neurodegeneration may be a promising biomarker for persistently CD. Further studies, including both longitudinal and repeated measurements of retinal layer thickness and cognitive function, are needed to assess the possibility of retinal thickness as a biomarker for persistent CD.