Peripheral and central capillary non-perfusion in diabetic retinopathy: An updated overview

PEST Proteolysis Signals Containing Nuclear Protein Related Proteins in Eye and Eye Diseases:A Review

The human visual system is a critical component for understanding the world around us, but it is affected by various eye conditions that lead to visual impairments. More than 2.2 billion people worldwide suffer from vision problems such as macular degeneration, refractive errors, cataracts, and glaucoma. In the field of iridology, essential proteins for maintaining healthy eye activity are often mutated or dysregulated. Clear vision is essential for people, and mutations related to these proteins can significantly impact the prevalence and development of eye disorders. Proteins that are linked to ocular disorders, including the nuclear protein Ras, S-glutathionylation, the human ER1 protein, and the Pest Proteolysis Signal-containing Nuclear Protein (PCNP), were examined in this study. Identifying and studying potential treatment targets and strategies to regulate the function of these proteins is crucial for minimizing the prevalence of eye disorders. PCNP is specifically linked to the development of several eye disorders. The development of clinical strategies to effectively treat ocular disorders will benefit from an understanding of these molecular processes. The main focus of this study was on PCNP because of due to its significant role in the pathophysiology of eye disorders. Understanding the function of this protein is vital, as its dysregulation has been linked with several ocular diseases. It is important to fully understand the roles of these essential proteins to develop effective treatments and preventive measures for ocular problems. This review therefore aims to contribute to advancements in the research, treatment, and management of preventable blindness and vision impairment globally by influencing thoughts on how to target and regulate these prospective remedies.

Predictors of Peripheral Retinal Non-Perfusion in Clinically Significant Diabetic Macular Edema

Background/Objectives: Diabetic macular edema (DME) is a significant cause of vision loss. The development of peripheral non-perfusion (PNP) might be associated with the natural course, severity, and treatment of DME. The present study seeks to understand the predictive power of central macular changes and clinico-demographic features for PNP in patients with clinically significant DME. Methods: A prospective study using contemporaneous multi-modal retinal imaging was performed. In total, 48 eyes with DME from 33 patients were enrolled. Demographic, clinical history, laboratory measures, ultrawide field photography, fluorescein angiography, optical coherence tomography (OCT), and OCT angiography results were acquired. Anatomic and vascular features of the central macula and peripheral retina were quantified from retinal images. Separate (generalized) linear mixed models were used to assess differences between PNP present and absent groups. Mixed effects logistic regression was used to assess which features have predictive power for PNP. Results: Variables with significant differences between eyes with and without PNP were insulin use (p = 0.0001), PRP treatment (p = 0.0003), and diffuse fluorescein leakage (p = 0.013). Importantly, there were no significant differences for any of the macular vascular metrics including vessel density (p = 0.15) and foveal avascular zone (FAZ) area (p = 0.58 and capillary tortuosity (p = 0.55). Features with significant predictive power (all p < 0.001) were subretinal fluid, FAZ eccentricity, ellipsoid zone disruption, past anti-VEGF therapy, insulin use, and no ischemic heart disease. Conclusions: In the setting of DME, macular vascular changes did not predict the presence of PNP. Therefore, in order to detect peripheral non-perfusion in DME, our results implicate the importance of peripheral retinal vascular imaging.

Diabetes Renders Photoreceptors Susceptible to Retinal Ischemia-Reperfusion Injury

Purpose

Studies have suggested that photoreceptors (PR) are altered by diabetes, contributing to diabetic retinopathy (DR) pathology. Here, we explored the effect of diabetes on retinal ischemic injury.

Methods

Retinal ischemia-reperfusion (IR) injury was caused by elevation of intraocular pressure in 10-week-old BKS db/db type 2 diabetes mellitus (T2DM) mice or C57BL/6J mice at 4 or 12 weeks after streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM), and respective nondiabetic controls. Retinal neurodegeneration was evaluated by retinal layer thinning, TUNEL staining, and neuron loss. Vascular permeability was evaluated as retinal accumulation of circulating fluorescent albumin. The effects of pretreatment with a sodium-glucose co-transporter (SGLT1/2) inhibitor, phlorizin, were examined.

Results

Nondiabetic control mice exhibited no significant outer retinal layer thinning or PR loss after IR injury. In contrast, db/db mice exhibited significant outer retina thinning (49%, P < 0.0001), loss of PR nuclei (45%, P < 0.05) and inner segment (IS) length decline (45%, P < 0.0001). STZ-induced diabetic mice at 4 weeks showed progressive thinning of the outer retina (55%, by 14 days, P < 0.0001) and 4.3-fold greater number of TUNEL+ cells in the outer nuclear layer (ONL) than injured retinas of control mice (P < 0.0001). After 12 weeks of diabetes, the retinas exhibited similar outer layer thinning and PR loss after IR. Diabetes also delayed restoration of the blood-retinal barrier after IR injury. Phlorizin reduced outer retinal layer thinning from 49% to 3% (P < 0.0001).

Conclusions

Diabetes caused PR to become highly susceptible to IR injury. The ability of phlorizin pretreatment to block outer retinal thinning after IR suggests that the effects of diabetes on PR are readily reversible.

Risk Factors for Worsening Morphology and Visual Acuity in Eyes with Adult-Onset Foveomacular Vitelliform Dystrophy

PURPOSE

To explore clinical risk factors and OCT features associated with worse visual acuity (VA), progression of disease, choroidal neovascularization (CNV), and atrophy in eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD).

DESIGN

Single-center, retrospective, observational cohort study.

PARTICIPANTS

Patients seen at Duke Eye Center between January 2012 and May 2023 with a diagnosis of AOFVD confirmed via OCT and fundus autofluorescence.

METHODS

Baseline and final-visit images from eyes with AOFVD were examined. Disease stage was assigned, and presence of atrophy or CNV was determined. Clinical and OCT features associated with progression to atrophy and CNV were determined using t tests and chi-square analysis. Correlation with lower VA was determined using linear regression.

MAIN OUTCOME MEASURES

Association of clinical characteristics and OCT features with worse VA, progression of disease, CNV, and atrophy as determined by independent t tests, chi-square analysis, and linear regression (P < 0.05).

RESULTS

One hundred one eyes (63 patients) met inclusion criteria for this study, with mean follow-up duration of 48 months (standard deviation, 31 months). Fifty-one percent of eyes progressed beyond baseline staging during follow-up; among baseline stage 1 eyes, incidence of atrophy was 0.068/person-year; incidence of CNV was 0.022/person-year. Risk factors for worse final VA were baseline presence of vitreomacular traction ([VMT], P = 0.006), ellipsoid zone attenuation (P = 0.02), and increased lesion height and width (P < 0.001). Predictors of progression include diabetes mellitus (P = 0.01), statin use (P = 0.03), presence of hyperreflective foci (P = 0.01), and increased lesion width and volume (P = 0.03 and P = 0.04, respectively). Predictors of atrophy include the baseline presence of VMT (P = 0.02), decreased choroidal thickness (P = 0.03), and greater maximal height, width, and volume of the lesion (P = 0.03, P = 0.02, and P = 0.009, respectively). Lower baseline VA (P = 0.03) and increased lesion volume (P = 0.04) were associated with CNV.

CONCLUSIONS

Clinical and OCT imaging features at baseline may prove useful in stratifying patient risk for progression, atrophy, CNV, and worse VA. Features such as statin use, diabetes, baseline VA, and laterality should be accounted for. OCT features, such as lesion size, VMT, ellipsoid zone attenuation, choroidal thickness, and hyperreflective foci, may impart greater risk of poor outcomes. Future prospective analysis accounting for the time to development of atrophy and CNV is needed.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Clinical Utilisation of Wide-Field Optical Coherence Tomography and Angiography: A Narrative Review

Many important abnormalities of the vitreous, retina and choroid are predominantly located in the peripheral retina. In some retinal diseases with both central and peripheral manifestations, pathological structural or vascular changes can be apparent in the periphery before they are detectable in the central retina. Conventional optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A) imaging only cover the most posterior 30° of the retina. Wide-field OCT (WF-OCT), though offering detailed cross-sectional imaging of the peripheral retina, is not yet systematically used in clinical practice. This narrative review provides a presentation of the utilisation of WF-OCT and WF-OCT-A in the diagnosis and monitoring of a variety of ophthalmological diseases and discusses the advantages and limitations of the technology. With the rapidly developing technology, multiple WF-OCT and WF-OCT-A devices are now commercially available and enable the clinician to obtain scans within a field of view up to 200°. As detailed in this review, several studies have shown promising results in the application of WF-OCT and WF-OCT-A in diseases of the retina, choroid and vitreous, such as retinal vein occlusion, diabetic retinopathy, ocular oncology, paediatric ophthalmology, uveitis and lesions of the vitreo-retinal interface. In conclusion, WF-OCT and WF-OCT-A can reliably produce high-quality, non-invasive images of the vitreous, retinal, and choroidal structures and vascularity covering the posterior pole as well as the mid and far periphery. These methods can be a valuable part of a multimodal imaging approach in the management of a variety of ocular conditions. Future studies are warranted to investigate the patient outcome benefits of implementation of WF-OCT and WF-OCT-A imaging in a real-life clinical setting.

New Imaging Technology for Simultaneous Multiwavelength-UWF Fundus Fluorescein Angiography and Indocyanine Green Angiography With Navigated Central and Peripheral SS-OCT

OBJECTIVE

Our aim was to assess central and peripheral retinal and choroidal diseases using novel simultaneous multiwavelength-ultra-widefield (MW-UWF) fundus fluorescein angiography (FFA)/indocyanine green angiography (ICGA) with navigated central and peripheral swept-source optical coherence tomography (SS-OCT) technology.

METHODS

Retrospective evaluation was carried out of 30 consecutive patients (60 eyes) who underwent UWF red/green (RG), infrared (IR), FFA and ICGA with simultaneous navigated SS-OCT using Optos Silverstone (Optos PLC). Angiographic retinal and choroidal findings in vascular pathologies and their relationship with the vitreoretinal interface (VRI) were assessed.

RESULTS

Simultaneous FFA with navigated SSOCT was performed in all patients and simultaneous FFA-ICGA with SS-OCT in 18 eyes (30%). Cross-sectional central and peripheral changes in the retina, choroid, and VRI corresponding with angiographic findings in several diseases were imaged.

CONCLUSION

First-in-human study of a new technology providing UWF RG/FFA/ICGA with simultaneous navigated central and peripheral SS-OCT can guide clinical management and provide new insights and understanding of central and peripheral retinal and choroidal disease. [Ophthalmic Surg Lasers Imaging Retina 2023;54:xx-xx.].