Outer Retinal Layers Research Articles

Analysis of Henle's fiber layer and outer retinal layers in cone dystrophy.

To evaluate Henle's Fiber Layer (HFL) thickness and volume parameters in patients with cone photoreceptor atrophy with directional optical coherence tomography (D-OCT). Macular 20°×20° standard and D-OCT images were acquired from patients diagnosed with hereditary cone dystrophy with evident foveal ellipsoid zone defect in OCT, and age-matched healthy controls. Thickness and volume parameters of HFL, outer nuclear layer (ONL) and retinal layers between ellipsoid zone and Bruch membrane complex (EZ-BM) were calculated from manual segmentation through D-OCT images and comparative analysis is performed. Twelve eyes of 6 patients were compared to 12 eyes of 6 age-matched healthy controls (mean age: 29.5±16.6 and 26.6±3.9 years respectively; P=0.162). Patients had lower total HFL volume (0.45±0.03 and 0.85±0.15 mm3; P<0.001) and mean HFL thickness (16.1±1.1 and 30.1±5.3 µm; P<0.001) than healthy controls. Central subfield, parafoveal and perifoveal ETDRS zone HFL parameters in patients were significantly lower than healthy controls. A centrifugal correlation was found between central ONL and the corresponding parafoveal HFL (Spearman's rho: 0.785; P<0.001). HFL assessment might be a useful OCT biomarker in patients with cone photoreceptor atrophy. HFL thinning is observed in foveal, parafoveal and perifoveal areas of patients with cone photoreceptor atrophy, while volume reduction in ONL and EZ-BM components were limited to central and parafoveal zones.

New high-resolution prototype versus standard spectralis optical coherence tomography in patients with central serous chorioretinopathy

PurposeTo assess the accuracy of High-Resolution OCT in detecting biomarkers associated with central serous chorioretinopathy (CSC) compared to standard OCT.MethodsWe conducted a cross-sectional study involving CSC patients who underwent High-Resolution and standard OCT during the same visit. Using the SPECTRALIS High-Res OCT device (Heidelberg Engineering, Heidelberg, Germany), macular B-scans were obtained and compared with those acquired using a SPECTRALIS HRA + OCT device (Heidelberg Engineering, Heidelberg, Germany). Qualitative assessments were performed, and statistical analyses compared the performance of both OCT modalities.ResultsThirty-one patients diagnosed with CSC were included with a mean age of 56.3 years (± 10.2). Among them, 29% (n = 9) were classified as acute CSC (aCSC), while 71% (n = 22) had chronic CSC (cCSC). High-Resolution OCT outperformed standard OCT in detecting microstructural changes in the outer retinal layers, including a higher prevalence of disrupted interdigitation zone (IZ) (29% vs. 6%, p = 0.003) and retinal pigment epithelium (RPE) disruption (12% vs. 2%, p = 0.0024). Intergrader agreement was high (Cohen’s Kappa = 0.85).ConclusionHigh-Resolution OCT demonstrates promise in identifying critical biomarkers associated with CSC, particularly disruptions in the IZ and RPE. Further validation in larger cohorts is required to confirm their clinical relevance in patients with CSC.

TEMPORARY AMNIOTIC MEMBRANE GRAFT PLACEMENT FOR TREATMENT OF REFRACTORY MACULAR HOLES.

To report two patient cases demonstrating the management of refractory macular holes through the application of temporary thin amniotic membrane grafts, followed by subsequent graft removal upon achieving hole closure. Comprehensive chart and literature review was conducted utilizing the PubMed database. We describe two patients who underwent repeat pars plana vitrectomy for treatment of refractory macular holes. In both cases, the epi-retinal placement of a thin amniotic membrane graft (AMG) was done to achieve hole closure. Following a period of retinal stabilization, the amniotic membranes were removed due to the healthy appearance of the outer retinal layers and the ellipsoid zone, ultimately resulting in an improved final visual acuity in both patients. This case series demonstrates a new approach of using a temporary AMG to close refractory macular holes. After graft removal, both patients reported enhanced visual acuity and subjective visual improvement, accompanied by the stable closure of macular holes on serial OCT scans.

Complete retinal pigment epithelium and outer retinal atrophy: Is it really an end-stage atrophy?

Geographic atrophy (GA), a late manifestation of age-related macular degeneration (AMD), leads to irreversible vision loss. Early identification of precursor lesions, such as incomplete and complete retinal pigment epithelium and outer retinal atrophy (iRORA and cRORA), is crucial for predicting GA formation. The latter stage has been associated with irreversible and progressive changes, and the eventual development of a dense scotoma on the compromised area. We present an 80-year-old woman with AMD in both eyes, demonstrating progressive changes over a 2-year follow-up. While the right eye developed cRORA with vision decline, the left eye exhibited unexpected restoration of the outer retinal layers within the cRORA lesion. This finding challenges the notion of "end-stage atrophy" in GA development and highlights the potential reversibility of early atrophic lesions. Recognizing these dynamics has implications for the development of targeted therapies aimed at preserving vision in AMD's early stages.

A comprehensive evaluation of efficacy of hyperbaric oxygen therapy in non-arteritic central retinal artery occlusion using enhanced depth imaging optical coherence tomography

This study aimed to assess the efficacy of hyperbaric oxygen therapy (HBOT) in patients with central retinal artery occlusion (CRAO) by analyzing changes in visual acuity (VA) and enhanced depth imaging optical coherence tomography (EDI-OCT) parameters. A comparative retrospective study was conducted by reviewing the medical records of all HBO-treated RAO patients in our department and comparing them with matched RAO patients who did not receive HBO treatment. All patients treated with HBO received treatment within 7 days of the onset of visual symptoms. Baseline characteristics were compared, and VA and OCT parameters were evaluated at baseline and follow-up visits. A total of 50 eyes from 50 patients were included, with 29 eyes in the HBOT group and 21 eyes in the control group. The mean BCVA of the HBOT group at the initial visit was 2.03 logMAR, which improved to 1.55 logMAR at 6 months, with the change being statistically significant (P < 0.01), while the control group's BCVA remained almost unchanged, from 2.1 to 2.11 logMAR (P = 0.762). The central choroidal thickness increased significantly in the HBOT group over the subsequent period. The central fovea, and outer retinal layer thickness in the HBOT group were significantly greater than those in the control group at the 6-month follow-up after treatment. HBOT appears to be effective in improving VA and inducing favorable changes in OCT parameters in patients with CRAO. It helps to preserve retinal layer thickness, especially in the outer retinal layer.

Multimodal imaging-based treatment recommendations for managing submacular hemorrhage.

Submacular haemorrhage (SMH) is an emergency, and the most important immediate action in the treatment of SMH is the early displacement or evacuation of subretinal heme from below the fovea, followed by simultaneous or sequential treatment of the underlying cause. Photoreceptor damage can occur immediately after the onset of SMH for a variety of reasons, including toxins released from the blood, the diffusion barrier created by the blood for oxygen delivery and nutrition to the outer retinal layers, and shearing forces on the outer retinal layers, resulting in permanent visual deterioration. A clinician's decision to treat SMH is influenced by a number of factors, including presenting visual acuity, duration of visual symptoms, SMH aetiology and characteristics, availability of intraocular gases and tissue plasminogen activator, and pars plana vitrectomy facilities. For many clinicians, the duration of visual symptoms is the most important and first consideration when planning SMH treatment. Very little emphasis is given to the SMH's imaging characteristics. Currently, there are several treatment options for SMH removal. There is a need to develop a simplified treatment algorithm for SMH that is less reliant on the patient's visual complaints, considers heme characteristics on basic retinal imaging, and has the potential to achieve uniform and predictable treatment outcomes in real-world situations. In this short article, we discuss the various factors that can assist clinicians in the management of SMH and present a simplified treatment algorithm based on the SMH's retinal imaging characteristics.

The Endogenous Expression of BMI1 in Adult Human Eyes.

BMI1, also known as B lymphoma Mo-MLV insertion region 1, is a protein in the Polycomb group that is implicated in various cellular processes, including stem cell self-renewal and the regulation of cellular senescence. BMI1 plays a role in the regulation of retinal progenitor cells and the renewal of adult neuronal cells. However, the presence, location, and quantification of BMI1 in the adult human eye have never previously been reported. In this study, we collected 45 frozen globes from eye banks, and ocular tissues were dissected. Protein was quantified by utilizing a custom electrochemiluminescence (ECL) assay developed to quantify the BMI1 protein. BMI1 was found in all ocular tissues at the following levels: the retina (1483.6 ± 191.7 pg/mL) and the RPE (296.4 ± 78.1 pg/mL). BMI1 expression was noted ubiquitously in the GCL (ganglion cell layer), the INL (inner nuclear layer), the ONL (outer nuclear layer), and the RPE (retinal pigment epithelium) via immunofluorescence, with higher levels in the inner than in the outer retinal layers and the RPE. These data confirm that BMI1 is expressed in the human retina. Further studies will illuminate the role that BMI1 plays in ocular cells. BMI1 levels are lower in aged retinas, possibly reflecting changes in retinal somatic and stem cell maintenance and disease susceptibility.

Deletion of the stress response protein REDD1 prevents sodium iodate-induced RPE damage and photoreceptor loss.

Age-related macular degeneration (AMD) is a leading cause of blindness in elderly populations, yet the molecular events that initiate the early retinal defects that lead to visual function deficits remain poorly understood. The studies here explored a role for the stress response protein Regulated in Development and DNA damage response 1 (REDD1) in the development of retinal pathology by using the oxidant stressor sodium iodate (NaIO3) to model dry AMD in mice. REDD1 protein abundance was increased in the retinal pigmented epithelium (RPE) and retina of mice administered NaIO3. In wild-type REDD1+/+ mice, reactive oxygen species (ROS) levels were robustly increased in the outer retinal layers 1 day after NaIO3 administration, with focal areas of increased ROS seen throughout the outer retina after 7 days. In contrast with REDD1+/+ mice, ROS levels were blunted in REDD1-/- mice after NaIO3 administration. REDD1 was also required for upregulated expression of pro-inflammatory factors in the RPE/retina and immune cell activation in the outer retina following NaIO3 administration. In REDD1+/+ mice, NaIO3 reduced RPE65 and rhodopsin levels in the RPE and photoreceptor layers, respectively. Unlike REDD1+/+ mice, REDD1-/- mice did not exhibit disrupted RPE integrity, retinal degeneration, or photoreceptor thinning. Overall, REDD1 deletion was sufficient to prevent retinal oxidative stress, RPE damage, immune cell activation, and photoreceptor loss in response to NaIO3. The findings support a potential role for REDD1 in the development of retinal complications in the context of dry AMD.

Histological assessment of the effect of 50mW red laser on retina at variable time intervals: animal model.

To assess the histopathological effect of 50milliWatt red laser pointer on mice retinal tissue at variable exposure times. The experimental study was conducted in the Postgraduate Laboratory of the Unit of Medical Physics, Department of Physiology, College of Medicine, Mustansiriyah University, Baghdad, Iraq, from November 2020 to April 2021, and comprised albino mice. Histopathological effects on the retinal tissues were evaluated microscopically using conventional haematoxylin and eosin stain just after being exposed to commercially available 50 milliWatt red laser pointers with 630nm wavelength at 1, 2 and 3 minutes, grouped as R1, R2 and R3, respectively. The laser beam was focussed on the right eye of the mice sedated with sodium pentobarbital, reserving the left eye for use as a control group. Data was analysed using SPSS 24. Of the 12 mice, 4(33.3%) were in each of the 3 groups. There was significantly destructive effect of red laser on retinal outer cellular layers in all the groups compared to the controls (p<0.05). The effect was significant between R1 and R2 (p=0.0001), and between R2 and R3 (p=0.02). The handheld commercial red laser pointers could harmfully affect a wide range of mice retina and choroid.

Macular exudate in idiopathic intracranial hypertension affects outer retina and visual acuity

BackgroundOptical coherence tomography (OCT) is suggested as a potential tool for retinal biomarkers in idiopathic intracranial hypertension (IIH). We explored how macular exudate (ME) affects retinal structure in IIH and...

Association of Various Optical Coherence Tomographic Patterns of Diabetic Macular Edema With Central Subfield Thickness and Visual Acuity: A Cross-Sectional Observational Study.

Introduction Diabetic macular edema (DME) is the most common and vision-threatening complication in diabetic patients with diabetic retinopathy (DR), especially in those with Type 2 diabetes mellitus. Optical coherence tomography (OCT) is a reliable tool most commonly used for assessing macular morphology and provides quantitative information on the macula. OCT also examines the outer retinal layers, which can predict visual outcomes. Thus, our study aims to identify the association of various OCT-detected DME morphological patterns with central subfield thickness (CST) and visual acuity. Materials and methods This is a cross-sectional observational study of 50 patients with DME detected on OCT who visited the Ophthalmology Department of Saveetha Medical College and Hospitals for a period of six months, from November 2023 to April 2024. A complete ocular examination, including best corrected visual acuity, scored with the logMAR scale, anterior segment examination, and fundus biomicroscopy using 90D and 78D lenses, was performed. Early Treatment of Diabetic Retinopathy Study (ETDRS) grading of DR into mild to very severe non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) was noted. Spectral-domain OCT was used to diagnose DME. The CST was measured, and DME was classified into four patterns: sponge-like retinal swelling (SLRS), cystoid macular edema (CME), subretinal fluid (SRF), and posterior hyaloid traction (PHT). Results In the present study, males represented 60%, and females represented 40%. The mean age of the patients was 58.07 ± 6.80 years, with a mean duration of diabetes of 11.91 ± 5.14 years. Of the 50 patients with 100 eyes, only 60 eyes showed DME on OCT. CME was the most common morphological pattern (37%), while the least common pattern was PHT (10%). No significant association was found between a specific morphological pattern and control of diabetes. The most common pattern observed was SLRS in moderate NPDR, CME in severe NPDR, SRF in very severe NPDR, and PHT in PDR. Very severe NPDR patients showed all patterns of DME, and the PHT pattern was observed only in very severe NPDR and PDR. The highest mean CST was observed in the very severe NPDR stage, and the least was in the moderate NPDR stage. The mean CST was highest in SRF patterns and lowest in SLRS patterns. The best mean visual acuity was observed in the SLRS pattern, while the worst mean visual acuity was observed in the SRF pattern, followed by the PHT pattern. Conclusion Our study highlights the importance of OCT in patients with diabetes, as OCT patterns of DME are critical for predicting visual outcomes in DR. Severe grades of DR are usually associated with SRF and PHT patterns. Since patients with SRF and PHT patterns have the worst visual outcomes, these patients, upon identification, need to be counseled about their poor visual prognosis. Those with less severe DR should be closely monitored and advised on effective diabetes control to prevent progression and protect their vision.

Longitudinal Changes of Clinical, Imaging, and Fluid Biomarkers in Preataxic and Early Ataxic Spinocerebellar Ataxia Type 2 and 7 Carriers.

Brain MRI abnormalities and increases in neurofilament light chain (NfL) have mostly been observed in cross-sectional studies before ataxia onset in polyglutamine spinocerebellar ataxias. Our study aimed to identify longitudinal changes in biological, clinical, and/or imaging biomarkers in spinocerebellar ataxia (SCA) 2 and SCA7 carriers over 1 year. We studied SCA2 and SCA7 carriers and controls (expansion-negative relatives) at the Paris Brain Institute. Inclusion criteria included Scale for the Assessment and Rating of Ataxia (SARA) scores between 0 and 15. Assessments at baseline, 6 months, and 12 months comprised neurologic, quality of life, orofacial motor, neuropsychological, and ophthalmologic examinations, along with gait and oculomotor recordings, brain MRI, CSF, and blood sampling. The primary outcome was the longitudinal change in these assessments over 1 year. We included 15 SCA2 carriers, 15 SCA7 carriers, and 10 controls between May 2020 and April 2021. At baseline, the ages were similar (41 [37, 46] for SCA2, 38 [28.5, 39.8] for SCA7, and 39.5 [31, 54.5] for controls, p = 0.78), as well the sex (p = 0.61); SARA scores were low but different (4 [1.25, 6.5] in SCA2, 2 [0, 11.5] in SCA7, and 0 in controls, p < 0.01). Pons and medulla volumes were smaller in SCAs (p < 0.05) and cerebellum volume only in SCA2 (p = 0.01). Plasma NfL levels were higher in SCA participants (SCA2: 14.2 pg/mL [11.52, 15.89], SCA7: 15.53 [13.27, 23.23]) than in controls (4.88 [3.56, 6.17], p < 0.001). After 1-year follow-up, in SCA2, there was significant pons (-144 ± 60 mm3) and cerebellum (-1,508 ± 580 mm3) volume loss and a worsening of gait assessment; in SCA7, SARA score significantly increased (+1.3 ± 0.4) and outer retinal nuclear layer thickness decreased (-15.4 ± 1.6 μm); for both SCA groups, the orofacial motor assessment significantly worsened. For preataxic and early ataxic carriers, the strongest longitudinal deterioration on outcome measures was orofacial motility in SCA2 and retinal thickness in SCA7. Despite the limitation of the small sample size, we detected annual changes in preataxic and early ataxic SCA individuals across brain MRI imaging, clinical scores, gait parameters, and retinal thickness. These parameters could serve as potential end points for future therapeutic trials in the preataxic phase. ClinicalTrials.gov NCT04288128.

Visual prognostic factors following surgery for stage 3 idiopathic epiretinal membrane by Govetto classification.

To investigate the visual prognosis of metamorphopsia in patients undergoing surgery for stage 3 idiopathic epiretinal membrane (ERM) by Govetto classification using preoperative optical coherence tomography (OCT) parameters. Retrospective clinical study. This study included 45 eyes of 45 patients with a minimum follow-up period of 3 months. The best-corrected visual acuity (BCVA) and metamorphopsia score using the M-CHARTS were recorded. Central foveal thickness (CFT), inner nuclear layer thickness (INL), ectopic inner retinal layer thickness (EIFL), outer retinal layer thickness, disruption of the ellipsoid zone, cotton ball sign, and intraretinal cystoid changes were measured based on spectral domain OCT. Preoperative and postoperative values and conditions were compared, and correlations between the preoperative values or conditions and postoperative metamorphopsia scores or BCVA were analyzed. After surgery, the horizontal, vertical, and mean metamorphopsia scores, as well as BCVA, CFT, INL, and EIFL significantly improved (p < 0.001). Using multivariate analysis, only preoperative CFT was a significant explanatory parameter for both the postoperative horizontal metamorphopsia scores and mean values of the postoperative horizontal and vertical metamorphopsia scores (p = 0.019 and p = 0.011, respectively). Age (p = 0.011) and preoperative CFT (p = 0.026) were significant explanatory parameters of postoperative BCVA. Preoperative CFT significantly correlated with postoperative metamorphopsia in patients undergoing surgery for stage 3 idiopathic ERM. This finding might help surgeons predict postoperative visual outcomes and make timely surgical decisions.

Deep learning aided measurement of outer retinal layer metrics as biomarkers for inherited retinal degenerations: opportunities and challenges.

The purpose of this review was to provide a summary of currently available retinal imaging and visual function testing methods for assessing inherited retinal degenerations (IRDs), with the emphasis on the application of deep learning (DL) approaches to assist the determination of structural biomarkers for IRDs. (clinical trials for IRDs; discover effective biomarkers as endpoints; DL applications in processing retinal images to detect disease-related structural changes). Assessing photoreceptor loss is a direct way to evaluate IRDs. Outer retinal layer structures, including outer nuclear layer, ellipsoid zone, photoreceptor outer segment, RPE, are potential structural biomarkers for IRDs. More work may be needed on structure and function relationship.

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.

Sources of Discrepancy between Retinal Nerve Fiber Layer and Bruch’s Membrane Opening-Minimum Rim Width Thickness in Eyes with Glaucoma

To compare the discrepancies between circumpapillary retinal nerve fiber layer (RNFL) and Bruch's membrane opening-minimum rim width (BMO-MRW) thickness in glaucoma eyes. A cross-sectional observational study. One hundred eighty-six eyes (118 patients) with glaucoma. OCT optic nerve head volume scans of patients enrolled in the Advanced Glaucoma Progression Study at the final available visit were exported. The RNFL and BMO-MRW measurements were averaged into corresponding 7.5° sectors, and the nasal sector data were excluded from analyses. A 2-stage screening process was used to identify true mismatches between the RNFL and BMO-MRW measurements, in which either the RNFL or BMO-MRW value was in the less than first percentile range while its counterpart was in the greater than first percentile range on the temporal-superior-nasal-inferior-temporal curve. The prevalence of these mismatches was mapped, and corresponding images were reviewed to determine the underlying cause of these discrepancies. Proportion of mismatches between RNFL and BMO-MRW, location of mismatches between RNFL and BMO-MRW, anatomical causes of mismatches between RNFL and BMO-MRW. Mismatch analysis revealed true mismatches between RNFL and BMO-MRW in 7.7% of sectors. High BMO-MRW with low corresponding RNFL mismatches were most frequently located at the 45° and 322.5° sectors, whereas high RNFL with corresponding low BMO-MRW mismatches peaked at the 75° sector. Large blood vessels accounted for 90.9% of high RNFL with low BMO-MRW mismatches. Small to large blood vessels accounted for 62.9% of high BMO-MRW with low RNFL mismatches; the remaining mismatches could be attributed to retinoschisis or inclusion of outer retinal layers in BMO-MRW measurements. Although overall agreement between RNFL and BMO-MRW measurements is good in areas with advanced damage, blood vessels and other anatomical factors can cause discrepancies between the 2 types of structural measurements and need to be considered when evaluating the utility of such measurements for detection of change. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Impact of cumulative dose of hydroxychloroquine on retinal structures.

What is known • Hydroxychloroquine (HCQ) is widely used for autoimmune disorders but is associated with the risk of retinal toxicity. • Early detection of retinal structural changes due to HCQ toxicity remains challenging, and cumulative HCQ dose as a risk factor has conflicting clinical relevance. What Is New • Higher cumulative HCQ doses are significantly associated with thinner outer retinal layers (foveal, parafoveal, and perifoveal regions). • No significant associations were found between HCQ cumulative dose and inner retinal thickness or age.

Comparison of surgical outcomes of macular telangiectasia type 2 associated macular hole with idiopathic macular hole: A tertiary center review.

To assess the longitudinal surgical outcomes of macular telangiectasia type 2 macular hole (MacTel-MH) and compare them with those of idiopathic MH. This retrospective, single-tertiary center study included patients who underwent MH surgery between January 2015 and September 2023. Patients with characteristic optical coherence tomography (OCT) findings of MacTel in both eyes or those who underwent fluorescence angiography were classified as having MacTel MH. Baseline and postoperative best-corrected visual acuity and OCT parameters were reviewed. Totally, 27 and 243 eyes with MacTel and idiopathic MH, respectively, were included. MH closure rate was better achieved in idiopathic than in MacTel MH group at 2 years postoperatively. Temporal recovery of ellipsoid zone and external limiting membrane was more prominent in MacTel than in idiopathic MH group. Statistically significant visual acuity improvement was seen between 3 months and 2 years postoperatively in MacTel MH group. To the best of our knowledge, this is the first study to analyze the surgical outcomes of MacTel MH in both anatomical and functional aspects and compare them with patients with idiopathic MH. Postoperative microglia change would have affected the restoration of outer retinal layer of patients; however, further studies are needed for clarification.

Evaluation of thickness of individual macular retinal layers in diabetic eyes from optical coherence tomography

The effect of diabetes mellitus (DM) on individual retinal layers remains incompletely understood. We evaluated the intra-retinal layer thickness alterations in 71 DM eyes with no diabetic retinopathy (DR), 90 with mild DR, and 63 with moderate DR without macular edema, using spectral-domain optical coherence tomography (SD-OCT) and the Iowa Reference Algorithm for automated retinal layer segmentation. The average thickness of 10 intra-retinal layers was then corrected for ocular magnification using axial length measurements, and pairwise comparisons were made using multivariable linear regression models adjusted for gender and race. In DM no DR eyes, significant thinning was evident in the ganglion cell layer (GCL; p < 0.001), inner nuclear layer (INL; p = 0.001), and retinal pigment epithelium (RPE; p = 0.014) compared to normal eyes. Additionally, mild DR eyes exhibited a thinner inner plexiform layer (IPL; p = 0.008) than DM no DR eyes. Conversely, moderate DR eyes displayed thickening in the INL, outer nuclear layer, IPL, and retinal nerve fiber layer (all p ≤ 0.002), with notably worse vision. These findings highlight distinctive patterns: early diabetic eyes experience thinning in specific retinal layers, while moderate DR eyes exhibit thickening of certain layers and slightly compromised visual acuity, despite the absence of macular edema. Understanding these structural changes is crucial for comprehending diabetic eye complications.

Electroretinographic changes in the inner and outer retinal layers before and after intravenous chemotherapy for retinoblastoma.

To study the inner and outer retinal functions using a full-field electroretinogram (ERG) before and after intravenous chemotherapy (IVC) in children with retinoblastoma (RB). Of the 11 eyes, seven had RB and four were normal. All children were examined under anesthesia using a handheld ERG machine with a standard protocol - light-adapted single-flash ERG (fERG), photopic single-flash 3.0- and 30-Hz flickers, and photopic negative response (PhNR) amplitudes at 72 ms (P72). The amplitudes and peak times were compared before and after IVC. Post-chemotherapy tumor regressed in all seven eyes. Of the seven eyes, the fERG peak time (a-wave) was delayed in two eyes (29%), whereas the b-wave was delayed in six eyes (86%). The fERG amplitude height for a- and b-waves decreased in five eyes (71%) and six eyes (86%), respectively. In addition, photopic flicker 30-Hz b-wave peak time delayed in five eyes (71%), whereas the b-wave amplitude height decreased in six eyes (86%). Simultaneously, the P72 amplitude height decreased in six eyes (86%), whereas the P-ratio increased in all seven eyes (100%). In comparison, the ERG responses improved in three of the four contralateral normal eyes. Overall, the cone function improved in two eyes (29%), whereas cone bipolar cell and retinal ganglion cell (RGC) function improved in one eye (14%) each. Comparison of light-adapted ERG changes before and after IVC showed reduced amplitudes and delayed peak times for both a and b waveforms, as well as reduced PhNR amplitude attributable to bipolar and RGC injury.