Total Retinal Thickness Research Articles

Total retinal thickness is an important factor in evaluating diabetic retinal neurodegeneration

ObjectiveMacular retinal nerve fibre layer (mRNFL) and ganglion cell-inner plexiform layer thickness (GC-IPL) measurements are important markers of diabetic retinal neurodegeneration (DRN). In this cross-sectional study, we aimed to quantify...

Multimodal Imaging Characteristics and Correlation to Outcomes in Patients with CRAO Presenting to a Large Academic Center

PurposeTo characterize a large modern cohort of patients with central retinal artery occlusion (CRAO) by describing presenting features and outcomes relating to manually segmented optical coherence tomography (OCT) features, angiographic reperfusion, and visual recovery. DesignRetrospective clinical cohort study. MethodsPatients with CRAO (ICD-10: H34.1) initially presenting to a tertiary referral center between January 2017 and December 2021 were included. Demographics, eye exam findings, fundus photographs, OCT, and fluorescein angiography (FA) were analyzed. Main outcome measures included total and inner retinal thickness on macular OCT, reperfusion, visual outcomes, and development of neovascularization. Results145 eyes of 144 patients with mean age at of 69.4±13.6 years were included. The mean time to presentation was 1.6±4.2 days, with 19% examined within 4.5 hours and 26% within 6 hours of vision loss. 19% had cilioretinal artery (CLRA) sparing. Mean initial visual acuity (VA) was 1.68±1.10 LogMAR (CLRA sparing) compared to 2.53±0.58 LogMAR (non-CLRA sparing), P<0.001. 32% had elevated inflammatory makers. Out of 47 eyes with final fluorescein angiography, one-third showed some reperfusion. Final vision was 1.40±1.16 LogMAR (CLRA sparing) compared to 2.46±0.81 (non-CLRA sparing), P<0.001. A third of patients improved in VA in both groups, 27% of patients gained more than 2 lines of vision in the CLRA sparing group and 36% in the non-CLRA sparing group. 17% improved to better than 20/200 in CLRA-sparing and 4% in non-CLRA sparing. 11% developed neovascularization all in non-CLRA sparing. In a multiple linear regression, VA at presentation was associated with regaining vision of 2 lines or more (OR=2.603, P=0.007). OCT showed progressive thinning over time, reaching lowest measurements at 6 months, and stabilizing thereafter. ConclusionsIn this modern cohort of acute CRAO patients, presentation to a tertiary facility within 12 hours of symptoms was seen in almost half of the patients. Final visual acuity improved in almost a third of the patients, however, vision better than the legal blindness limit was rare (∼5%). Interestingly, a third of patients had some mild elevation of systemic inflammatory markers. Better visual acuity at presentation was associated with visual gain, while baseline OCT values had poor correlation with final outcome.

Internal Limiting Membrane Peeling for Large Macular Holes Induces Only Structural Remodeling without Functional Impairment Over 12 Years

To evaluate the very long-term functional and structural outcomes of internal limiting membrane (ILM) peeling for full-thickness macular holes (FTMH). Observational case series nested within a multicenter, randomized, controlled clinical trial (RCT) (ClinicalTrials.gov: NCT00190190). Patients who underwent vitrectomy with or without ILM peeling for an idiopathic large FTMH in a tertiary ophthalmology center, with a minimum follow-up of 10 years after surgery. Review of charts, spectral-domain OCT (SD-OCT) scans, OCT angiography (OCTA) scans, and microperimetry of patients originally enrolled in the RCT. Primary outcome was functional assessment in both groups (ILM peeling or not) including the retinal sensitivity (RS), distance and near best-corrected visual acuity (BCVA), and number of eyes achieving ≥0.3 logarithm of the minimum angle of resolution >10 years after surgery. Secondary outcomes were structural assessment in the entire 3× 3-mm and 6× 6-mm areas, and regionally in the different areas of the ETDRS grid: OCT and OCTA biomarkers in both groups and fellow eyes. Thirteen eyes of 13 patients with a mean follow-up of 12 ± 0.73 years were included. The mean RS and BCVA, or visual improvement did not differ between ILM peeling (n= 8) and no peeling (n= 5) (all P > 0.05). The dissociated optic nerve fiber layers on en face OCT were only observed in eyes with ILM peeling, predominantly in temporal parafoveal (20%) and perifoveal (19%) rings. The mean total retinal thickness and inner retinal thickness in the parafoveal ring were significantly lower in peeled eyes (309 ± 11 μm and 94 ± 9 μm respectively) versus nonpeeled eyes (330 ± 21 μm and 108 ± 11 μm respectively; P= 0.037 and P= 0.040), without significant difference in ganglion cell or retinal nerve fiber layers. Accordingly, the mean superficial capillary plexus density in the parafoveal ring was significantly lower in eyes with peeling versus without (39.65 ± 3.76 % versus 47.22 ± 4.00; P= 0.005). The mean foveal avascular zone area was smaller in eyes with peeling versus without (0.24 ± 0.05 mm2 vs. 0.42 ± 0.13 mm2, respectively, P= 0.005). Despite persistent structural changes especially in the parafoveal ring, ILM peeling for idiopathic large FTMH did not seem to impact long-term RS or BCVA over 12 years. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Differences in macular thickness associated with peripheral retinal vessel whitening in diabetic patients

This study aimed to determine the difference in macular thickness among patients with diabetes mellitus (DM) with and without peripheral retinal vessel whitening (PRVW). PRVW was defined by retinal vessel whitening outside the standard seven ETDRS fields. Subjects were divided into DM with PRVW, DM without PRVW, and normal age-matched controls. Optical coherence tomography scans were divided into total, inner, and outer retinal layer thicknesses and were compared in the macula's central, inner, and outer rings. Forty-seven eyes were included: DM with PRVW = 15, DM without PRVW = 16, and Controls = 16. Overall, the mean retinal thickness in patients with DM with PRVW was lower than in patients with DM without PRVW and controls. In the inner macula, DM patients with PRVW showed a significantly lower mean inner superior, nasal, inferior, and temporal macula compared to DM patients without PRVW (p = 0.014, 0.008, 0.005, < 0.001, respectively). DM patients with PRVW also showed a significantly lower mean outer superior, nasal, inferior, and temporal macula than controls (p = 0.005, 0.005, 0.016, 0.025, respectively). This study demonstrates that PRVW in DM patients may be associated with global structural changes to the macular region, promoting a decrease in inner and outer retinal thickness. Further studies should investigate the functional correlation with PRVW in DM patients in order to better understand its potential implications in diabetic patients.

Optic Nerve Head Morphology and Macula Ganglion Cell Inner Plexiform Layer Thickness in Axially Anisometropic Rhesus Monkeys.

The purpose of this study was to determine the effects of axial elongation on optic nerve head morphology and macula inner retinal thickness in young rhesus monkeys. Both eyes of 26 anisometropic, 1-year-old rhesus monkeys were imaged using optical coherence tomography (OCT). Before imaging, the animals were sedated, their eyes were dilated, and axial length was measured using an optical biometer. OCT imaging included a 20 degrees, 24-line radial scan centered on the optic nerve head (ONH) and two 20 degrees × 20 degrees raster scans, one centered on the ONH and the other on the macula. Radial scans were analyzed using programs written in MATLAB to quantify the Bruch's membrane opening (BMO) area and position, minimum rim width (MRW), anterior lamina cribrosa surface (ALCS) position, size of any scleral crescent, circumpapillary retinal nerve fiber layer (RNFL), and choroid thickness (pCh). Macula total retinal thickness (mTRT) and ganglion cell inner plexiform layer (GCIPL) thicknesses were quantified from macula scans. Linear least square regression was determined for OCT measures and axial length of the right eye, and for inter-eye differences. Animals were 341 ± 18days old at the time of imaging. BMO area (R2 = 0.38), ALCS position (R2 = 0.45), scleral crescent area (R2 = 0.35), pCh thickness (R2 = 0.21), mTRT (R2 = 0.24), and GCIPL thickness (R2 = 0.16) were correlated with the axial length (all P < 0.05). For each of these parameters, the right-eye regression slope did not differ from the slope of the interocular difference (P > 0.57). There are posterior segment morphological differences in anisometropic rhesus monkeys related to axial length. Whether these differences increase the risk of pathology remains to be investigated.

Severe Spaceflight-Associated Neuro-Ocular Syndrome in an Astronaut With 2 Predisposing Factors

Understanding potential predisposing factors associated with spaceflight-associated neuro-ocular syndrome (SANS) may influence its management. To describe a severe case of SANS associated with 2 potentially predisposing factors. Ocular testing of and blood collections from a female astronaut were completed preflight, inflight, and postflight in the setting of the International Space Station (ISS). Weightlessness throughout an approximately 6-month ISS mission. Mean carbon dioxide (CO2) partial pressure decreased from 2.6 to 1.3 mm Hg weeks before the astronaut's flight day (FD) 154 optical coherence tomography (OCT) session. In response to SANS, 4 B-vitamin supplements (vitamin B6, 100 mg; L-methylfolate, 5 mg; vitamin B12, 1000 μg; and riboflavin, 400 mg) were deployed, unpacked on FD153, consumed daily through FD169, and then discontinued due to gastrointestinal discomfort. Refraction, distance visual acuity (DVA), optic nerve, and macular assessment on OCT. Cycloplegic refraction was -1.00 diopter in both eyes preflight and +0.50 - 0.25 × 015 in the right eye and +1.00 diopter in the left eye 3 days postflight. Uncorrected DVA was 20/30 OU preflight, 20/16 or better by FD90, and 20/15 OU 3 days postflight. Inflight peripapillary total retinal thickness (TRT) peaked between FD84 and FD126 (right eye, 401 μm preflight, 613 μm on FD84; left eye, 404 μm preflight, 636 μm on FD126), then decreased. Peripapillary choroidal folds, quantified by surface roughness, peaked at 12.7 μm in the right eye on FD154 and 15.0 μm in the left eye on FD126, then decreased. Mean choroidal thickness increased throughout the mission. Genetic analyses revealed 2 minor alleles for MTRR 66 and 2 major alleles for SHMT1 1420 (ie, 4 of 4 SANS risk alleles). One-week postflight, lumbar puncture opening pressure was normal, at 19.4 cm H2O. To the authors' knowledge, no other report of SANS documented as large of a change in peripapillary TRT or hyperopic shift during a mission as in this astronaut, and this was only 1 of 4 astronauts to experience chorioretinal folds approaching the fovea. This case showed substantial inflight improvement greater than the sensitivity of the measure, possibly associated with B-vitamin supplementation and/or reduction in cabin CO2. However, as a single report, such improvement could be coincidental to these interventions, warranting further evaluation.

Evaluation of ophthalmic vascular and neuroretinal alterations in fibromyalgia syndrome: a cross-sectional comparative study

IntroductionFibromyalgia syndrome (FMS) is a prevalent rheumatic disorder, and its pathogenesis includes genetic, neuroendocrine, and autonomic abnormalities, which may impact ocular structures. The aim was to conduct a comparative analysis of the ophthalmic vasculature and the retinal nerve fiber layer (RNFL) thickness between FMS and control groups using optical coherence tomography (OCT) and OCT angiography (OCTA).MethodsThis cross-sectional comparative study included 43 FMS patients and 40 healthy controls recruited from a tertiary education and research hospital between January 2024 and May 2024. All patients satisfied the 2016 American College of Rheumatology criteria for FMS and consented. OCT and OCTA were used to assess the RNFL thickness and the retinal microvasculature structure. The Fibromyalgia Impact Questionnaire (FIQ) was performed to evaluate disease severity.ResultsThe study found significantly higher total retinal parafoveal thickness and foveal density in FMS patients (p = 0.017 and p = 0.044, respectively). Nevertheless, there were no significant differences among the groups concerning total retinal foveal thickness, foveal avascular zone characteristics, superficial and deep capillary plexus densities, choriocapillaris flow area, and outer retinal flow area values (p > 0.05). The RNFL thickness in all quadrants did not reveal significant differences between the groups (p > 0.05). Furthermore, there was no significant correlation between FIQ scores and OCTA parameters or RNFL thickness values (p > 0.05).ConclusionThe study revealed slight differences in retinal parafoveal thickness and foveal density in FMS patients, but no substantial vascular or neurodegenerative alterations were observed compared to healthy controls. These data indicate that FMS may not substantially affect ocular structures, contrary to earlier hypotheses.

Assessment of retinal atrophy in mixed breed dogs using spectral domain optical coherence tomography (SD-OCT) and electroretinography.

The aim of the study was to characterize retinal atrophy (RA) with progressive retinal atrophy symptoms in mixed breed dogs using ophthalmoscopy, spectral domain optical coherence tomography (SD-OCT) and electroretinography (ERG).The study was performed on 13 mixed breed dogs affected by retinal atrophy (11 males and 2 females that were 1.5-14 years old). Depending on the advancement of RA, SD-OCT examinations identified retinal abnormalities ranging from layer disorganisation to advanced atrophy. The most advanced RA occurred ventral to the optic disc. Total retinal thickness in both eyes (mean ± SD) was lower in dogs with RA compared to controls dorsally (77.7 ± 39.5 μm vs 173.5 ± 13.3 μm), ventrally (33.4 ± 29.9 μm vs 139.5 ± 10.8 μm), nasally (65.0 ± 34.5 μm vs 163.9 ± 11.0 μm) and temporally (61.8 ± 41.7 μm vs 171.9 ± 11.1 μm) to the optic disc. In dogs with locally normal architecture of inner retina, loss of definition of outer retinal layers occurred in many regions. Dark and light-adapted ERGs were reduced in 2 dogs with RA and were unrecordable in 11 dogs. Lesions evident in SD-OCT scans of mixed breed dogs affected with retinal atrophy initially appear ventrally to the optic disc and ventro-dorsally in advanced RA. In all mixed breed dogs with retinal atrophy, clinical signs and SD-OCT results correlate with ERG findings.

RETINAL STRUCTURAL CHANGES AFTER CESSATION OF PENTOSAN POLYSULFATE SODIUM.

To quantify baseline and longitudinal structural changes post-cessation in patients with pentosan polysulfate sodium retinopathy. This is a retrospective cohort study. Retinal thickness and volume of choroidal and hyperreflective retinal pigment epithelium excrescences were manually segmented from optical coherence tomography volume scans. Baseline measurements were compared against age-matched control subjects. Longitudinal measurements were performed on patients with follow-up data. Twenty-four eyes of 13 patients were included. At baseline, the mean total retinal thickness was lower in the pentosan polysulfate sodium retinopathy cohort than in age- and sex-matched control subjects (269.1 µ m vs. 290.2 µ m, P = 0.006). The median (range) of follow-up was 18.6 (4.1-34.7) months, with the mean last follow-up of 35.2 months after cessation. During the follow-up period, the thickness of the retina decreased significantly by 11.3 µ m (CI: 16.8, 5.8) ( P < 0.001), with an annual mean decrease of 6.70 µ m. However, the mean hyperreflective retinal pigment epithelium excrescence volume did not change significantly ( P = 0.140) over the follow-up period. After pentosan polysulfate sodium discontinuation, although retinal pigment epithelium excrescence volume do not change significantly, there continues to be a progressive long-term thinning of the retina, which continues at a rate greater than that associated with normal aging. Consequently, long-term follow-up is suggested to monitor patients with pentosan polysulfate sodium retinopathy.

Visual function and retinal thickness in children with type 1 diabetes mellitus

ABSTRACT Clinical Relevance The possibility that changes in blue–yellow visual thresholds and some retinal thickness measures in children with diabetes mellitus may be observed before any visible fundus changes points to the possibility of these measures being a useful predictor that the risks of diabetic retinopathy are higher in some children than in others. Introduction Previous studies showed mixed results on chromatic and achromatic contrast sensitivity early in the course of diabetes mellitus, and the findings of these studies may have been influenced by a lack of experimental sensitivity to visual deficits, a bias towards tritan-like errors or the cognitive demands of the tests and variations in sample composition. The purpose of this study was to evaluate colour and contrast thresholds and retinal thickness in children with type 1 diabetes mellitus compared with age-matched controls. Methods A prospective case–control study was carried out on 9–14-year-old children with type 1 diabetes mellitus (49 cases) and age matched controls (49) in which isoluminant red–green and blue–yellow and achromatic luminance contrast thresholds were measured. Fundus photography was used to grade diabetic retinopathy. Retinal thickness parameters were measured using optical coherence tomography. Data on the duration of diabetes mellitus, glycaemic control (HbA1c), blood glucose level, body mass index, blood pressure and blood oxygenation at the time of testing were obtained. Results The cases mostly had poorly controlled diabetes, HbA1c 8.6% (6.4–12.8%), for an average (range) duration of 5 (0.4–12) years. The cases had significantly higher blue–yellow thresholds (p = 0.02) and greater total retinal and inner retinal thickness (p < 0.05) than controls. No cases had diabetic retinopathy. Within the cases, poorer visual function and systemic health measures were associated with thinner retinal structures and greater global loss volume percentage in the ganglion cell complex. Conclusion Blue–yellow thresholds of cases were raised compared to normal. Within the cases, higher luminance contrast thresholds were also associated with, mostly, ganglion cell complex reductions.

Visual Field Prognosis From Macula and Circumpapillary Spectral Domain Optical Coherence Tomography.

To explore the structural-functional loss relationship from optic-nerve-head- and macula-centred spectral-domain (SD) Optical Coherence Tomography (OCT) images in the full spectrum of glaucoma patients using deep-learning methods. A cohort comprising 5238 unique eyes classified as suspects or diagnosed with glaucoma was considered. All patients underwent ophthalmologic examination consisting of standard automated perimetry (SAP), macular OCT, and peri-papillary OCT on the same day. Deep learning models were trained to estimate G-pattern visual field (VF) mean deviation (MD) and cluster MD using retinal thickness maps from seven layers: retinal nerve fiber layer (RNFL), ganglion cell layer and inner plexiform layer (GCL + IPL), inner nuclear layer and outer plexiform layer (INL + OPL), outer nuclear layer (ONL), photoreceptors and retinal pigmented epithelium (PR + RPE), choriocapillaris and choroidal stroma (CC + CS), total retinal thickness (RT). The best performance on MD prediction is achieved by RNFL, GCL + IPL and RT layers, with R2 scores of 0.37, 0.33, and 0.31, respectively. Combining macular and peri-papillary scans outperforms single modality prediction, achieving an R2 value of 0.48. Cluster MD predictions show promising results, notably in central clusters, reaching an R2 of 0.56. The combination of multiple modalities, such as optic-nerve-head circular B-scans and retinal thickness maps from macular SD-OCT images, improves the performance of MD and cluster MD prediction. Our proposed model demonstrates the highest level of accuracy in predicting MD in the early-to-mid stages of glaucoma. Objective measures recorded with SD-OCT can optimize the number of visual field tests and improve individualized glaucoma care by adjusting VF testing frequency based on deep-learning estimates of functional damage.

Linkage of Diabetic Retinopathy with Blood Antioxidants and Gut Microbiota in Type Two Diabetes Mellitus Saudi Patients

Background: The retina is a light-sensitive nerve layer located at the back of the eye that creates images of objects. These cells kept alive by getting oxygen and nutrients from tiny blood vessels in the eye. Retinopathy is a disease of the retina that is more prevalent in type 2 diabetes mellitus patients. Diabetic retinopathy is a leading cause of blindness because hyperglycemia weakens retinal capillaries, resulting in leakage of blood into the surrounding space. This bleeding can result in formation of scar tissue, which can cause traction retinal detachment and maculopathy. The development of a panel of blood biomarkers to monitor diabetic retinopathies is essential for both diagnosis and prognosis. Proteomics as a powerful tool for the analysis of complex mixtures of proteins and the identification of biomarkers can be of great importance. Purpose: To detect early nerve fiber layer changes around macula and optic disc in diabetic patients and to correlate diabetic retinopathy with blood antioxidants and gut microbiota in T2DM in Saudi patients. Materials and Methods: In this cross-sectional case-control study, a total of 77 eyes of 39 subjects aged 40-60 years who did not have any history of eye injuries or eye diseases affecting fundus viewing, were recruited from King Saud University Campus and the department of ophthalmology in King Abdul Aziz university hospital in Riyadh. All subjects underwent full ophthalmic examination including Peripapillary retinal nerve fiber layer thickness and macular profile, Proteomic approach of collected overnight fasting plasma and Microbial stool examination. Results: The nerve fiber layer thickness around the optic disc was measured for all groups and there was no statistically significant difference in all quadrants between groups. The total retinal thickness at the macular area was different among all groups and tends to increase in group 3 due to diabetic retinopathy. The macular thickness in the 4 quadrants revealed no statistical difference except in the inferior quadrant. Glutathione S transferase and lipid peroxides showed no significant difference between the three studied groups; vitamin C and Glutathione were surprisingly higher in controlled diabetic patients relative to controls. Moreover, over growth of bacteroids participated to the evolution of retinopathy in diabetic patients. Conclusion: As hyperglycemia and oxidative stress are implicated in the pathogenesis of diabetic retinopathy, the present study certified that the progressive damage can be delayed in controlled type 2 diabetic patients using different treatment modalities that subside oxidative stress.

Foveal thickness and its association with visual acuity in adults born preterm with very low birth weight: A two-country birth cohort study.

To explore foveal and parafoveal thickness in adults born preterm with very low birth weight (VLBW) and its association with best-corrected visual acuity (BCVA) and gestational age (GA) compared to adults born at term. In a joint study of the Helsinki Study of Very Low Birth Weight Adults (Finland) and the NTNU Low Birth Weight Life study (Norway), 106 VLBW and 143 term-born controls were examined with spectral-domain optical coherence tomography and BCVA at age 31-43 years. Thickness of retinal layers was segmented in the foveal and parafoveal areas of the macula. The total retinal thickness in the foveal area was thicker in VLBW adults compared with controls; mean (SD): 292.5 μm (28.2) and 272.4 μm (20.2); p < 0.001, and thinner in the parafoveal areas of the macula. These findings could be explained by a thicker inner retinal layer in the foveal area found in VLBW adults compared with controls (mean difference 20.4 μm; CI: 15.0 to 25.9), where a thicker fovea was associated with lower GA, but not BCVA. Adults born preterm with VLBW had a thicker retina in the foveal area than controls and this was associated with GA, but not with BCVA. These changes seem to be related to a thicker inner retinal layer in VLBW adults. The findings imply that signs of macular underdevelopment are still present in adulthood, but not necessarily related to reduced visual function.

Structural correlations between brain magnetic resonance image-derived phenotypes and retinal neuroanatomy.

The eye is a well-established model of brain structure and function, yet region-specific structural correlations between the retina and the brain remain underexplored. Therefore, we aim to explore and describe the relationships between the retinal layer thicknesses and brain magnetic resonance image (MRI)-derived phenotypes in UK Biobank. Participants with both quality-controlled optical coherence tomography (OCT) and brain MRI were included in this study. Retinal sublayer thicknesses and total macular thickness were derived from OCT scans. Brain image-derived phenotypes (IDPs) of 153 cortical and subcortical regions were processed from MRI scans. We utilized multivariable linear regression models to examine the association between retinal thickness and brain regional volumes. All analyses were corrected for multiple testing and adjusted for confounders. Data from 6446 participants were included in this study. We identified significant associations between volumetric brain MRI measures of subregions in the occipital lobe (intracalcarine cortex), parietal lobe (postcentral gyrus), cerebellum (lobules VI, VIIb, VIIIa, VIIIb, and IX), and deep brain structures (thalamus, hippocampus, caudate, putamen, pallidum, and accumbens) and the thickness of the innermost retinal sublayers and total macular thickness (all p < 3.3 × 10-5). We did not observe statistically significant associations between brain IDPs and the thickness of the outer retinal sublayers. Thinner inner and total retinal thicknesses are associated with smaller volumes of specific brain regions. Notably, these relationships extend beyond anatomically established retina-brain connections.

Possible retinotoxicity of long-term vardenafil treatment

Phosphodiesterase (PDE) inhibitors – such as vardenafil – are used primarily for treating erectile dysfunction via increasing cyclic guanosine monophosphate (cGMP) levels. Recent studies have also demonstrated their significant cardioprotective effects in several diseases, including diabetes, upon long-term, continuous application. However, PDE inhibitors are not specific for PDE5 and also inhibit the retinal isoform. A sustained rise in cGMP in photoreceptors is known to be toxic; therefore, we hypothesized that long-term vardenafil treatment might result in retinotoxicity. The hypothesis was tested in a clinically relevant animal model of type 2 diabetes mellitus. Histological experiments were performed on lean and diabetic Zucker Diabetic Fatty rats. Half of the animals were treated with vardenafil for six months, and the retinal effects were evaluated. Vardenafil treatment alleviated rod outer segment degeneration but decreased rod numbers in some positions and induced changes in the interphotoreceptor matrix, even in control animals. Vardenafil treatment decreased total retinal thickness in the control and diabetic groups and reduced the number of nuclei in the outer nuclear layer. Müller cell activation was detectable even in the vardenafil-treated control animals, and vardenafil did not improve gliosis in the diabetic group. Vardenafil-treated animals showed complex retinal alterations with improvements in some parameters while deterioration in others. Our results point towards the retinotoxicity of vardenafil, even without diabetes, which raises doubts about the retinal safety of long-term continuous vardenafil administration. This effect needs to be considered when approving PDE inhibitors for alternative indications.

Glycemic Variability and the Thickness of Retinal Layers in Cystic Fibrosis Patients with and without Cystic Fibrosis Related Diabetes

Purpose Patients with cystic fibrosis (CF) are at risk to develop CF related diabetes (CFRD) and subsequently even diabetic neuro- and/or vasculopathy. We sought to determine if there are typical signs of diabetes-related retinal alterations present in CF patients with preserved and impaired glycemic control. Methods During routine annual examination CF patients were offered an additional 7-day period of real time continuous glucose monitoring (rtCGM) and an ophthalmological examination including retinal optical coherence tomography (OCT). Patients were categorized according to the glycemic control, i.e. the results of an oral glucose tolerance test (OGTT) and rtCGM were taken into consideration. OCT data was analyzed by our previously published visual analysis software generating dedicated and spatially resolved deviation maps for visualization and quantification of differences in total retinal thickness and thickness of retinal nerve fiber layer (RNFL) as well as ganglion cell layer (GCL) in comparison to age-matched healthy controls and patients with either type 1 or type 2 diabetes mellitus. Results Results of the rtCGM and/or OGTT enabled discrimination between patients with normal glycemic control (CFNG; n = 6), with abnormal glycemic control (CFAG; n = 6) and overt CFRD (n = 4). OCT data indicates gradually increasing retinal thinning in all 3 groups, depending on the degree of glucose metabolism disorder compared to healthy controls. At the foveal region total retinal thickness and GCL thickness were significantly thinner in CFRD patients compared to CFNG patients (total retinal thickness: 260.4 µm (239.3–270.8) vs. 275.4 µm (254.3–289.5); GCL: 11.82 µm (11.16–15.25) vs. 17.30 µm (13.95–19.82); each p < 0.05). Conclusion Although we investigated a rather small number of patients, we obtained evidence that intraretinal neurodegenerative changes occur in each of our subgroups (CFNG, CFAG, CFRD). Beyond this, our results favor the detrimental role of additional diabetes, as the deviations from healthy controls were most pronounced in the CFRD group and are similar to those seen in patients suffering from type 1 or type 2 diabetes.

Attention flexibility is associated with retinal cup-to-disk ratio in patients with schizophrenia spectrum disorders

IntroductionIn recent years, there has been increasing interest in the potential use of retinal imaging as a non-invasive and easily accessible tool for investigating the neurobiological underpinnings of schizophrenia. Studies have suggested that patients with schizophrenia spectrum disorders (SSD) have structural abnormalities in the retina, including changes in retinal thickness and the ratio of the retinal cup-to-disk ratio.ObjectivesTo investigate the relationship between retinal cup-to-disk ratio and cognitive performance in patients with SSD using a high-definition retinal imaging device – optical coherence tomography (OCT) scanner.MethodsThe sample was comprised of twenty patients with SSD (F20-F29 according to ICD-10 criteria). All diagnoses were confirmed by a researcher using the Mini International Psychiatric Interview. All patients underwent complete ophthalmological examination, excluding any ocular pathology. Retinal thickness was measured in both eyes of all patients with a high-definition spectral-domain OCT device. Examined retinal parameters were: total retinal nerve fiber layer thickness (RNFL); RNFL thickness in all eye quadrants (nasal, temporal, superior, inferior); RNFL symmetry; average macular volume (MV); average macular thickness (MT); ganglion cell layer thickness (GC); average retinal cup-to-disk (C/D) ratio, vertical C/D ratio. Cognitive performance of all patients was tested using the Intra/Extradimensional Set Shift Task (IED). IED is a component of a state-of-the-art computerized battery for cognitive assessment – Cambridge Neuropsychological Automated Test Battery. IED is a measure of maintenance, shifting and flexibility of attention. Associations between retinal variables and IED measures were determined with Pearson correlation analyses.ResultsMean age of patients was 33 ± 7.5 years. Fifty five percent of the sample was male, illness duration was 6.2 ± 3.9 years. Daily dosage of chlorpromazine was 225.7 ± 108.8 mg. Retinal C/D ratio in the right eye was positively associated with IED total errors (r=0.50; p=0.02) and negatively with IED stage progression (r=-0.52, p=0.18). Likewise, vertical C/D ratio was positively associated with IED total errors (r=0.49; p=0.02) and negatively with IED stage progression (r=-0.52, p=0.18).ConclusionsPrevious analyses of retinal parameters in patients with schizophrenia point towards enlargement of retinal cup-to-disk ratio, irrespective of any underlying somatic comorbidities. Our data shows worsening of attention flexibility in association with the increase of cup-to-disk ratio in patients with schizophrenia spectrum disorders. The significance of cup-to-disk retinal disturbance in schizophrenia spectrum disorders and its connection with cognitive performance should be further evaluated and supplemented with measurements of functional adaptation in these patients.Disclosure of InterestNone Declared

Linkage of diabetic retinopathy with blood antioxidants and gut microbiota in type two diabetes mellitus Saudi patients

Background: The retina is a light-sensitive nerve layer located at the back of the eye that creates images of objects. These cells kept alive by getting oxygen and nutrients from tiny blood vessels in the eye. Retinopathy is a disease of the retina that is more prevalent in type 2 diabetes mellitus patients. Diabetic retinopathy is a leading cause of blindness because hyperglycemia weakens retinal capillaries, resulting in leakage of blood into the surrounding space. This bleeding can result in formation of scar tissue, which can cause traction retinal detachment and maculopathy. The development of a panel of blood biomarkers to monitor diabetic retinopathies is essential for both diagnosis and prognosis. Proteomics as a powerful tool for the analysis of complex mixtures of proteins and the identification of biomarkers can be of great importance. Purpose: To detect early nerve fiber layer changes around macula and optic disc in diabetic patients, and to correlate diabetic retinopathy with blood antioxidants and gut microbiota in T2DM in Saudi patients. Materials and Methods: In this cross-sectional case-control study, a total of 77 eyes of 39 subjects aged 40-60 years who did not have any history of eye injuries or eye diseases affecting fundus viewing, were recruited from King Saud University Campus and the department of ophthalmology in King Abdul Aziz university hospital in Riyadh. All subjects underwent full ophthalmic examination including Peripapillary retinal nerve fiber layer thickness and macular profile, Proteomic approach of collected overnight fasting plasma and Microbial stool examination. Results: The nerve fiber layer thickness around the optic disc was measured for all groups, and there was no statistically significant difference in all quadrants between groups. The total retinal thickness at the macular area was different among all groups and tends to increase in group 3 due to diabetic retinopathy. The macular thickness in the 4 quadrants revealed no statistical difference except in the inferior quadrant. Glutathione S transferase and lipid peroxides showed no significant difference between the three studied groups; vitamin C and Glutathione were surprisingly higher in controlled diabetic patients relative to controls. Moreover, over growth of bacteroids participated to the evolution of retinopathy in diabetic patients. Conclusion: As hyperglycemia and oxidative stress are implicated in the pathogenesis of diabetic retinopathy, the present study certified that the progressive damage can be delayed in controlled type 2 diabetic patients using different treatment modalities that subside oxidative stress.

Long-term impact of low-energy femtosecond laser and manual cataract surgery on macular layer thickness: A prospective randomized study.

To evaluate change in retinal layers 18 months after femtosecond laser-assisted cataract surgery (LCS) and manual cataract surgery (MCS) in a representative age-related cataract population using artificial intelligence (AI)-based automated retinal layer segmentation. This was a prospective, randomized and intraindividual-controlled study including 60 patients at the Medical University of Vienna, Austria. Bilateral same-day LCS and MCS were performed in a randomized sequence. To provide insight into the development of cystoid macular oedema (CME), retinal layer thickness was measured pre-operatively and up to 18 months post-operatively in the central 1 mm, 3 mm and 6 mm. Fifty-six patients completed all follow-up visits. LCS compared to MCS did not impact any of the investigated retinal layers at any follow-up visit (p > 0.05). For the central 1 mm, a significant increase in total retinal thickness (TRT) was seen after 1 week followed by an elevated plateau thereafter. For the 3 mm and 6 mm, TRT increased only after 3 weeks and 6 weeks and decreased again until 18 months. TRT remained significantly increased compared to pre-operative thickness (p < 0.001). Visual acuity remained unaffected by the macular thickening and no case of CME was observed. Inner nuclear layer (INL) and outer nuclear layer (ONL) were the main causative layers for the total TRT increase. Photoreceptors (PR) declined 1 week after surgery but regained pre-operative values 18 months after surgery. Low-energy femtosecond laser pre-treatment did not influence thickness of the retinal layers in any topographic zone compared to manual high fluidic phacoemulsification. TRT did not return to pre-operative values 18 months after surgery. The causative layers for subclinical development of CME were successfully identified.

The Impact of a Single Haemodialysis Session on the Retinal Thickness and Optic Nerve Morphology

Background: The aim of the study was to assess the influence of a single haemodialysis (HD) session on the retinal and optic nerve morphology in end-stage kidney disease (ESKD) patients. Methods: It is a prospective study including only the right eye of 35 chronic kidney disease (CKD) patients subjected to HD. Each patient underwent a full eye examination 30 min before HD (8 a.m.) and 15 min after HD. Optical coherence tomography (OCT) was used to assess the peripapillary retinal nerve fibre layer (pRNFL) thickness, macular nerve fibre layer (mRNFL) thickness, ganglion cell layer with inner plexiform layer thickness (GCL+), GCL++ (mRNFL and GCL+) thickness, total retinal thickness (RT) and total macular volume (TMV). The correlation was tested between such systemic parameters changes as systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), body weight, plasma osmolarity and ocular perfusion pressure (OPP) and ultrafiltration volume with total RT and pRNFL thickness changes during HD. Results: In the results of a single HD session, we could observe a statistically significant increase in the total RT thickness (pre-HD 270.4 ± 19.94 μm, post-HD 272.14 ± 20.11 μm; p = 0.0014), TMV (pre-HD 7.48 ± 0.53 mm3, post-HD 7.52 ± 0.55 mm3; p = 0.0006), total pRNFL thickness (pre-HD 97.46 ± 15.71 μm, post-HD 100.23 ± 14.7 μm; p = 0.0039), total GCL+ thickness (pre-HD 70.11 ± 9.24 μm, post-HD 70.6 ± 9.7 μm; p = 0.0044), and GCL++ thickness (pre-HD 97.46 ± 12.56 μm, post-HD 97.9 ± 12.94 μm; p = 0.0081). We observed a significant correlation between the change in total RT and DBP change, as well as between body weight change and the change in total pRNFL thickness. There was also a correlation between total pRNFL thickness change and the presence of diabetes mellitus. Conclusion: Even a single HD session affects the retinal and pRNFL thickness, which should be taken into account when interpreting the OCT results in patients subjected to HD. The impact of changes after a single HD session on selected parameters requires further assessment in subsequent studies, including long-term observation.