Spectral Optical Coherence Tomography Research Articles

Evaluation of cerebral microcirculation in a mouse model of systemic inflammation.

Perturbations in the microcirculatory system have been observed in neurological conditions, such as Alzheimer's disease or systemic inflammation. However, changes occurring at the level of the capillary are difficult to translate to biomarkers that could be measured macroscopically. We aim to evaluate whether transit time changes reflect capillary stalling and to what degree. We employ a combined spectral optical coherence tomography (OCT) and fluorescence optical imaging (FOI) system to investigate the relation between capillary stalling and transit time in a mouse model of systemic inflammation induced by intraperitoneal injection of lipopolysaccharide. Angiograms are obtained using OCT, and fluorescence signal images are acquired by the FOI system upon intravenous injection of fluorescein isothiocyanate via a catheter inserted into the tail vein. Our findings reveal that lipopolysaccharide (LPS) administration significantly increases both the percentage and duration of capillary stalling compared to mice receiving a 0.9% saline injection. Moreover, LPS-induced mice exhibit significantly prolonged arteriovenous transit time compared to control mice. These observations suggest that capillary stalling, induced by inflammation, modulates cerebral mean transit time, a measure that has translational potential.

Line-field dynamic optical coherence tomography platform for volumetric assessment of biological tissues.

Dynamic optical coherence tomography (dOCT) utilizes time-dependent signal intensity fluctuations to enhance contrast in OCT images and indirectly probe physiological processes in cells. Majority of the dOCT studies published so far are based on acquisition of 2D images (B-scans or C-scans) by utilizing point-scanning Fourier domain (spectral or swept-source) OCT or full-field OCT respectively, primarily due to limitations in the image acquisition rate. Here we introduce a novel, high-speed spectral domain line-field dOCT (SD-LF-dOCT) system and image acquisition protocols designed for fast, volumetric dOCT imaging of biological tissues. The imaging probe is based on an exchangeable afocal lens pair that enables selection of combinations of transverse resolution (from 1.1 µm to 6.4 µm) and FOV (from 250 × 250 µm2 to 1.4 × 1.4 mm2), suitable for different biomedical applications. The system offers axial resolution of ∼ 1.9 µm in biological tissue, assuming an average refractive index of 1.38. Maximum sensitivity of 90.5 dB is achieved for 3.5 mW optical imaging power at the tissue surface and maximum camera acquisition rate of 2,000 fps. Volumetric dOCT images acquired with the SD-LF-dOCT system from plant tissue (cucumber), animal tissue (mouse liver) and human prostate carcinoma spheroids allow for volumetric visualization of the tissues' cellular and sub-cellular structures and assessment of cellular motility.

Does collagen cross linking have any effect on retinal circulation in patients with keratoconus? An optical coherence tomography angiography (OCTA) study

BackgroundWe aimed to employ Optical Coherence Tomography Angiography (OCTA) to comprehensively assess changes in the optic nerve head (ONH) and macular perfusion before and after the Corneal Collagen Cross-Linking (CCL) procedure in patients with keratoconus.MethodsA total of 22 keratoconus patient’s candidate for CCL procedures were included based on specific criteria, with meticulous exclusion criteria in place to minimize potential confounders. Participants underwent OCTA assessments of the ONH and macula using the Spectralis OCT (Heidelberg) before CCL, as well as at 1- and 3-months post-CCL. MATLAB software was utilized for image analysis.ResultsThe mean age of the participants was 20.09 ± 6.11, including 59% male, and the mean intraocular pressure (IOP) before the surgery was 13.59 ± 2.85 mmHg. Peripapillary Retinal nerve fiber layer (ppRNFL) thickness and overall retinal thickness remained stable post-CCL. However, significant alterations were observed in macular vessel density, emphasizing regional variations in vascular response. For macular large vessel density (LVD), both superficial and deep vascular complex (SVC and DVC) demonstrated significant differences between before surgery and the 3 months post-surgery follow-up (p < 0.001 and p = 0.002, respectively). Optic nerve head markers demonstrated relative stability, except for changes in avascular complex density, which was 49.2 ± 2.2% before the surgery and decrease to 47.6 ± 1.7% three months after the operation (P-value = 0.005).ConclusionWhile CCL appears to maintain the integrity of certain ocular structures, alterations in macular perfusion post-CCL suggest potential effects on retinal blood supply. Long-term monitoring is crucial to understand the implications of these changes, particularly in the context of conditions such as diabetes.

Effect of intravitreal injections due to neovascular age-related macular degeneration on retinal nerve fiber layer thickness and minimum rim width: a cross sectional study

PurposeThe present study tested the hypothesis that repeated anti-VEGF injections are associated with reduced retinal nerve fiber layer (RNFL) and minimum rim width (MRW) of the optic nerve head.Patients and methodsSixty-six patients with a history of intravitreal injections due to neovascular age-related macular degeneration were included. RNFL and MRW were measured using optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany).ResultsMean global RNFL was 90.62 μm and both RNFL as well as MRW significantly decreased with advanced age (p = 0.005 and p = 0.019, respectively). Correlating for the number of injections, no significant impact on RNFL was found globally (p = 0.642) or in any of the sectors. In contrast, however, global MRW was significantly reduced with increasing numbers of intravitreal injections (p = 0.012). The same holds true when adjusted for the confounding factor age (RNFL p = 0.566 and MRW p = 0.023).ConclusionOur study shows that repeated intravitreal injections due to choroidal neovascularization seem to have a deleterious effect on MRW but not on RNFL. This suggests that MRW is a more sensitive marker than RNFL for evaluating the effect of frequent intravitreal injections on the optic nerve head since it seems to be the first structure affected.

RETINAL MICROVASCULOPATHY WITH DIFFERENT INSULIN INFUSION THERAPIES IN CHILDREN WITH TYPE 1 DIABETES MELLITUS WITHOUT CLINICAL DIABETIC RETINOPATHY.

To explore the characteristics and associated factors of retinal microvasculopathy and neurodegeneration with different insulin therapies in children with type 1 diabetes mellitus (T1DM) but without diabetic retinopathy. Forty-one children with T1DM with multiple daily insulin injections (MDI), 22 children with T1DM with continuous subcutaneous insulin infusion, and 62 age-matched normal control children were enrolled. SPECTRALIS Optical coherence tomography was used to scan 6×6 mm square area of posterior retina. The vessel density of superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus in T1DM-MDI group were all significantly lower than those in the T1DM-CSII and control groups (0.39 ± 0.05 vs. 0.44 ± 0.04 and 0.42 ± 0.06, P < 0.001; 0.26 ± 0.04 vs. 0.30 ± 0.02 and 0.28 ± 0.04, P = 0.003; 0.30 ± 0.04 vs. 0.33 ± 0.04 and 0.32 ± 0.04, P = 0.027). In T1DM-MDI group, lower vessel density of superficial vascular plexus was associated with higher hemoglobin A1c (r = -0.377, P = 0.015). Foveal avascular zone morphology index in T1DM-MDI and T1DM-CSII groups were smaller than that in the control group (0.63 ± 0.11 and 0.63 ± 0.12 vs. 0.69 ± 0.15, P = 0.040). There was no statistically significant difference in the thickness of the retina among the three groups ( P > 0.05). The vessel density of posterior retina was lower in children with T1DM with MDI than in healthy control children and associated with higher hemoglobin A1c. There was a significant difference on vessel density betweenT1DM-MDI and T1DM-CSII, with the similar hemoglobin A1c. This study suggested that optical coherence tomography angiography could be beneficial for the detection of retinal abnormalities in children with early T1DM, and continuous subcutaneous insulin infusion may be a better choice than MDI for children with T1DM to prevent the retinal complication.

Thicker Inner Nuclear Layer as a Predictor of Glaucoma Progression and the Impact of Intraocular Pressure Fluctuation.

Background: Thickening of the inner nuclear layer (INL) or microcystic macular changes has been reported to be implicated in glaucoma patients, but their potential impact on disease progression remains unclear. We investigated the relationship between baseline microcystic macular edema in the INL or INL thickness and subsequent visual field (VF) progression in glaucoma patients. Methods: This retrospective observational study included primary open-angle glaucoma with follow-up exceeding 3 years. We identified macular cystic changes through Spectralis optical coherence tomography and measured the INL thickness using automated segmentation. Glaucoma progression was determined using the Guided Progression Analysis program of the Humphrey filed analyzer, calculating the mean deviation (MD) changes (dB/year). Results: Microcystic macular changes were observed in 12 (7.5%) of 162 patients. Patients with microcystic macular change had thicker INL thickness than those without it (p = 0.010). Progressors had a higher probability of having microcystic macular changes and a thicker average INL thickness than nonprogressors (p = 0.003, p = 0.019). Thicker INL thickness was associated with faster VF progression based on MD slope (dB/year) in the multivariate regression analysis (p = 0.045). Additionally, greater intraocular pressure (IOP) fluctuation was found to be associated with both a thicker INL and the presence of microcystic changes in the multivariate regression analysis (p = 0.003, 0.028). Conclusions: Increased macular INL thickness indicative of INL changes was linked to subsequent VF progression in glaucoma patients. These findings suggest that retinal inner nuclear change could serve as an indicator of progressive glaucoma.

Atypical phacolytic glaucoma diagnosed by biometry and anterior segment optical coherence tomography (OCT) in a patient with CMV anterior uveitis.

To report a case of phacolytic glaucoma with atypical presentation in a patient which was diagnosed with biometry swept source optical coherence tomography (SS-OCT) and anterior segment spectral domain OCT (SD-OCT). A 56-year-old male with a history of cytomegalovirus (CMV) chronic anterior uveitis in the right eye presented with a white cataract, minimal anterior chamber reaction and intraocular pressure (IOP) of 56 mmHg. Visual acuity was light perception. The anterior chamber was deep, without evidence of macroscopically visible capsular rupture. A surgical intervention was necessitated with the puzzle being whether to proceed with a trabeculectomy or a combined phaco-trabeculectomy. After a routine preoperative assessment with intraocular lens Master700, the disintegration of the natural lens was noticed. Anterior segment Spectralis OCT confirmed a lamellar separation of the anterior one third of the lens, resembling a poultaceous material. After an uneventful phacoemulsification, visual acuity was 6/6, IOP was well-controlled on maximum topical antiglaucoma treatment and no CMV recurrence was observed. The diagnosis of phacolytic glaucoma was established with the aid of current imaging OCT systems. Both OCT images were suggestive of a phacolytic nature of our case, despite the fact that the clinical presentation was not in concordance with such a typical case. In view of our findings the decision was to proceed with cataract extraction alone. This is the first time that we image and document the phacolytic nature of a natural lens. Our patient did not have the typical clinical presentation and was differentially diagnosed with biometry SS-OCT and confirmed by anterior segment SD-OCT.

Advances in Photoreceptor and Retinal pigment epithelium Quantifications in intermediate AMD: High-Res versus Standard SPECTRALIS OCT

Purpose: In this study we investigated differences in retinal feature visualization of high-resolution optical coherence tomography (OCT) devices with different axial resolutions in quantifications of retinal pigment epithelium (RPE) and photoreceptors (PR) in intermediate age-related macular degeneration (iAMD). Methods: Patients were imaged with standard SPECTRALIS HRA+OCT and the investigational High-Res OCT device (both by Heidelberg Engineering, Heidelberg, Germany). Drusen, RPE and PR layers were segmented using validated AI-based algorithms followed by manual corrections. Thickness- and drusen maps were computed for all patients. Loss and thickness measurements were compared between devices, drusen vs. non-drusen areas and EDTRS subfields using mixed-effects models. Results: Thirty-three eyes from 28 iAMD patients were included. Normalized PR integrity loss was significantly higher with 4.6% for standard OCT compared to 2.5% on High-Res OCT. The central and parafoveal PR integrity loss was larger than perifoveal loss (p&lt;0.05). PR thickness was increased on High-Res OCT and in non-drusen regions (p&lt;0.001). RPE appeared thicker on standard OCT and above drusen (p&lt;0.01). Conclusion: Our study shows that High-Res OCT is able to identify the condition of investigated layers in iAMD with higher precision. This improved in vivo imaging technology might promote our understanding of the pathophysiology and progression of AMD.

Peripheral Choroidal Response to Localized Defocus Blur: Influence of Native Peripheral Aberrations.

This study aims to examine the short-term peripheral choroidal thickness (PChT) response to signed defocus blur, both with and without native peripheral aberrations. This examination will provide insights into the role of peripheral aberration in detecting signs of defocus. The peripheral retina (temporal 15°) of the right eye was exposed to a localized video stimulus in 11 young adults. An adaptive optics system induced 2D myopic or hyperopic defocus onto the stimulus, with or without correcting native peripheral ocular aberrations (adaptive optics [AO] or NoAO defocus conditions). Choroidal scans were captured using Heidelberg Spectralis OCT at baseline, exposure (10, 20, and 30minutes), and recovery phases (4, 8, and 15minutes). Neural network-based automated MATLAB segmentation program measured PChT changes from OCT scans, and statistical analysis evaluated the effects of different optical conditions over time. During the exposure phase, NoAO myopic and hyperopic defocus conditions exhibited distinct bidirectional PChT alterations, showing average thickening (10.0 ± 5.3µm) and thinning (-9.1 ± 5.5µm), respectively. In contrast, induced AO defocus conditions did not demonstrate a significant change from baseline. PChT recovery to baseline occurred for all conditions. The unexposed fovea did not show any significant ChT change, indicating a localized ChT response to retinal blur. We discovered that the PChT response serves as a marker for detecting peripheral retinal myopic and hyperopic defocus blur, especially in the presence of peripheral aberrations. These findings highlight the significant role of peripheral oriented blur in cueing peripheral defocus sign detection.

A Comparative Study of Central Foveal Thickness in Nondiabetics Versus Diabetics Without Retinopathy Using Spectralis OCT

Abstract Purpose: To compare the central foveal thickness (CFT) in diabetics without retinopathy versus nondiabetics using optical coherence tomography (OCT). Methods: The study was done as a comparative cross-sectional study among two groups with 30 subjects in each group. Group A was of diabetics without retinopathy and Group B was of nondiabetics. Patients with diabetic retinopathy, diabetic macular edema, other macular diseases, history of laser treatment, intra vitreal injections, chronic glaucoma, previous eye surgeries, and hypertension were excluded from the study. CFT of the two groups was measured using OCT. Results: All the data were analyzed with a statistical software package SPSS version 16.0. The mean CFT in the diabetics without retinopathy group was found to be 225.97 ± 21.20 µm, and in nondiabetic group it was 234.57 ± 34.68 µms. Conclusion: The study showed that CFT was slightly lower in diabetics without retinopathy when compared to nondiabetics, but the value was not statistically significant (P-value: 0.091).

Screening for multifocal intraocular lens implantation in cataract patients in a public hospital.

To identify the rate and characteristics of cataract surgery candidates suitable for multifocal intraocular lens implantation among patients undergoing preoperative evaluation in a public hospital. Screening was performed based on the patient's medical records, comprehensive ophthalmic examination, optical biometry (Zeiss, IOL Master 700) and optical coherence tomography (OCT) (Heidelberg, OCT Spectralis) in accordance with the relevant indications and contraindications mentioned in the pertinent literature. Patients were included in the present study if they were eligible for bilateral cataract surgery. The exclusion criteria were the presence of central nervous system or motility issues, prior refractive surgery, the presence of astigmatism greater than 1 dioptre and/or the presence of important ocular comorbidities in either eye. The study evaluated 1200 consecutive patients. Four hundred thirty-two patients (36%) were not eligible for bilateral surgery and were excluded from the study. Of the 768 patients included in the present study, 346 (45.1%) were considered suitable candidates. Four hundred twenty-two patients (54.9%) were excluded for one or both eyes. Among them, 121 (28.7%) were excluded because of retinal disease, 120 (28.4%) because of regular astigmatism (> 1.0 D of corneal astigmatism), 32 (7.5%) because of pseudoexfoliation or zonular instability, and 30 (7.1%) because of glaucoma or ocular hypertension; in addition, 90 (21.3%) patients were excluded for multiple reasons. Suitable candidates were significantly younger (70 and 75 years, respectively) (p < 0.001). After being informed about the potential risks and benefits of MOIL implantation, 212 of 346 (83.8%) eligible patients provided consent. Close to half of cataract patients in a public hospital were eligible for MOIL implantation, and the majority of patients would proceed to surgery. The most prevalent contraindication was macular disease.

Comparing 2-dimensional macular pigment optical density with objective and subjective perimetry and visual acuity in age-related macular degeneration.

To compare diagnostic power for different severities of age-related macular degeneration (AMD) of two-dimensional macular pigment optical densities (2D-MPOD) and spatially matched objective perimetry, with standard perimetry and best-corrected visual acuity (BCVA). The ObjectiveField Analyser (OFA) provided objective perimetry, and a Heidelberg Spectralis optical coherence tomography (OCT) measured 2D-MPOD in AMD patients, both completed twice over 0.99 ± 0.16years. From each 2D-MPOD image, we extracted 20 regions/macula, matched to the 20 OFA stimuli/macula. For each region, we calculated 7 measures from the 2D-MPOD pixel values and correlated those with OFA sensitivities and delays. We quantified 2D-MPOD changes, the ability of 2D-MPOD and OFA to discriminate AMD stages, and the discriminatory power of Matrix perimetry and BCVA using percentage area under receiver operator characteristic plots (%AUROC). In 58 eyes of 29 subjects (71.6 ± 6.3years, 22 females), we found significant correlations between 2D-MPOD and OFA sensitivities for Age-Related Eye Disease Studies (AREDS)-3 and AREDS-4 severities. Delays showed significant correlations with AREDS-2. For AREDS-4, correlations extended across all eccentricities. Regression associated with the Bland-Altman plots showed significant changes in 2D-MPOD over the study period, especially variability measures. MPOD per-region medians discriminated AREDS-1 from AREDS-3 eyes at a %AUROC of 80.0 ± 6.3%, outperforming OFA, Matrix perimetry, and BCVA. MPOD changes correlated with central functional changes and significant correlations extended peripherally in later-stage AMD. Good diagnostic power for earlier-stage AMD and significant change over the study suggest that 2D-MPOD and OFA may provide effective biomarkers.

En Face and Volumetric Comparison of Hypertransmission Defects Evaluated by Cirrus and Spectralis Optical Coherence Tomography

PurposeTo evaluate and compare en face and 3-dimensional (D) properties of hypertransmission defects (HTDs) between different optical coherence tomography (OCT) devices using OCT volumes and reconstructed en face images. SettingsComparative diagnostic evaluation study. MethodsThirty eyes with dry age-related macular degeneration (AMD) that underwent dense OCT macular volume scans with both the Spectralis (97 B-scans/volume; 2,910 B-scans in total) and Cirrus OCT (128 B-scans/volume; 3,840 B-scans in total) from AMISH EYE STUDY cohort were included in this analysis. HTD regions were labeled on each B-scan and reconstructed into en face and 3-D volume images. Properties of HTD volume were compared between the two devices. ResultsQualitative score of en face images for HTD was higher for the Cirrus compared to the Spectralis (P < 0.01). The quality of Spectralis en face images improved after preprocessing and reconstruction. The 2-D HTD area on en face obtained from 2-D projections of 3-D volume did not differ between devices (P = 0.478; ICC 0.998; Jaccard index 0.721 ± 0.086). There was no difference in the number, volume, PALs, and surface areas of HTDs between devices in the volumetric analysis (all P ≥ 0.090). The signal intensity of HTD normalized by the mean choroidal signal intensity did not differ between devices (P = 0.861). ConclusionsThe visualization of HTD on en face images from Spectralis OCT could be enhanced through image processing. The equivalence in 3-D HTD parameters between the two devices suggests interchangeability for assessing these lesions in AMD.

Comparison of retinal thickness measurements among four different optical coherence tomography devices

We sought to compare the retinal thickness measurements collected using different optical coherence tomography (OCT) devices. This prospective study included 21 healthy cases, and the retinal thickness was measured using the PLEX Elite (Carl Zeiss Meditec, Dublin, California, USA), DRI OCT-1 Atlantis (Topcon Corp, Tokyo, Japan), Cirrus 5000 HD-OCT (Carl Zeiss Meditec), and Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany), respectively. The mean central retinal thickness (CRT) and mean retinal thickness of the Early Treatment of Diabetic Retinopathy Study (ETDRS) area were compared. The CRT varied significantly among the different OCT devices (P < 0.001). Post-hoc analysis revealed that the CRT measured using PLEX Elite (278.95 ± 20.04 µm) and Spectralis (271.86 ± 17.92 µm) were similar, and both were greater than the CRT measurements of DRI OCT-1 (239.57 ± 21.06 µm) and Cirrus (256.76 ± 17.82 µm). Additionally, the mean retinal thickness in each ETDRS area showed significant differences among the four devices (all P < 0.001). The mean retinal thickness measured varied according to the device used, and this needs to be considered when comparing retinal thickness measurements taken with different devices.

COMPARISON OF ANGLE OPENING DISTANCE AND TRABECULAR IRIS SPACE AREA BEFORE AND AFTER LASER PERIPHERAL IRIDOTOMY IN ANGLE CLOSURE DISEASE

&#x0D; &#x0D; &#x0D; Introduction and Objective: Laser peripheral iridotomy (LPI) is the standard first-line therapy in angle closure disease to increase anterior chamber angle width. Spectral Domain Anterior Segment Optical Coherence Tomography (SD AS-OCT) is an instrument that has a quantitative parameter to measure anterior chamber angle. Angle opening distance (AOD) and trabecular iris space area (TISA) are quantitative parameters in SD AS-OCT. The purpose of this study is to compare AOD and TISA before and one week after LPI in angle closure disease.&#x0D; Methods: This is an analytical prospective study with a cross-sectional study design. Twenty-two eyes with angle closure disease that met inclusion and exclusion criteria underwent LPI and SD AS-OCT before and one week after LPI. Analysis was performed using SD AS-OCT parameters, such as AOD (AOD500, AOD750) and TISA (TISA500, TISA750) in the temporal, nasal quadrants, and average.&#x0D; Results: Twenty-two eyes with angle closure are divided into nine eyes with primary angle closure suspect, seven eyes with primary angle closure, and six eyes with primary angle closure glaucoma. The mean age of participants was 57.86±7.63 years. There was a significant increase in AOD500, AOD750, TISA500, and TISA750 in the temporal and nasal quadrants, as well as in the average (P=0.0001) based on a paired t test or Wilcoxon as an alternative. Average AOD750 had the highest T-value (T= 6.329) with a mean 0.20±0.096 before LPI and 0.31±0.144 one week after LPI.&#x0D; Conclusion: There was a significant increase in AOD and TISA after one week LPI in angle closure disease.&#x0D; &#x0D; &#x0D;

Optical coherence tomography angiography of the macula of high myopia in children and adolescents

BackgroundHigh myopia represents a health issue and leads to the development of complications that threaten vision. The study of macular changes in high myopia patients has undergone great advances with updated technology via new spectral optical coherence tomography (OCT) and Optical coherence tomography angiography (OCTA). Most of related studies have focused on the adults and additional studies need to investigate macular changes in children and adolescents. This study aimed to evaluate the changes in the macular structure by OCT and the macular vessel density in high myopia in children and adolescents by OCTA.MethodsA cross-sectional comparative study. The population was divided into two groups: group 1 (4–11 years) and group 2 (12–18 years). The results were comparable to those of control study of the same age group. The two high myopia groups and the control groups were examined by macular OCT and OCTA to evaluate macular thickness and vessel density in the superficial and deep capillary plexuses.ResultsOCT measurements of patients in group 1 revealed that central macular thickness was significantly lower in high myopia group than in the control group and measured 220.91 ± 27.87 μm and 258.23 ± 17.26 μm, respectively, (P < 0.0001). However, in group 2 the central macular thickness in the high myopia group and control group was 236.32 ± 27.76 μm and 247.09 ± 16.81 μm respectively, and the difference was not statistically significant (P = 0.09). The parafoveal macular thickness and the perifoveal macular quadrants thickness were significantly lower in high myopic children and high myopic adolescents (P < 0.0001) than age matched controls. The parafoveal and perifoveal vessel densities in the superficial and deep capillary plexuses were lower in the high myopia groups than in the age-matched controls in both groups with a few segment exceptions in group 1. The FAZ was significantly wider in group 1 than in the age-matched emmetropes (P = 0.02). The FAZ was wider in group 2 than controls, but the difference was not statistically significant, (P = 0.75).ConclusionHigh myopic children and adolescents have thinner macular thickness than comparable age-matched emmetropes and have less vessel density in superficial and deep capillary plexuses with a wider FAZ.

Choroidal Thickness in Mild Autonomous Cortisol Secretion.

To evaluate the patients with mild autonomous cortisol secretion (MACS) by means of choroidal thickness (CT) and also investigate whether CT may be a diagnostic tool in the management of MACS or not. Twenty-seven patients with MACS and 25 age-sex-matched healthy controls were enrolled in this cross-sectional comparative study. All the participants underwent CT measurement by using Spectralis optical coherence tomography (Heidelberg Engineering, Heidelberg, Germany) with enhanced deep imaging mode at the subfoveal, 500-1000-1500 µm nasal and 500-1000-1500 µm temporal to the foveola. The groups were similar in terms of spherical equivalence, age and axial lengths. The mean CT was significantly thicker in patients with MACS than controls in all measurement quadrants (p<0.001). There was no significant correlation between CT, size of the adenoma, basal cortisol, 1mg dexamethasone suppression test, salivary cortisol, 24-hour total urine-free cortisol, ACTH and DHEAS levels. However, 2 mg dexamethasone suppression test results were found to be significantly correlated with CT in temporal 500-1000 and 1500 µm quadrants (r=0.436, p=0.023, r=0.443, p=0.021 and r=0.488, p=0.010, respectively). Five (18.5%) eyes had pachychoroid pigment epitheliopathy in the MACS group. CT increases in patients with MACS and those tend to have pachychoroid pigment epitheliopathy more frequent than healthy individuals. A thicker choroid in the patients with MACS may be a novel biomarker both as a diagnostic tool for the degree of hypercortisolemia and cortisol-related comorbidity.

Popper and maculopathy

Aims/Purpose: To describe a case of a patient with poppers maculopathy.Methods: The ocular findings were evaluated with spectral optical coherence tomography and fundus imaging.Results: A 23‐year‐old female presented with a history of central phosphenes and decreased vision after inhaling popper. Best‐corrected visual acuity (VA) was 0.9/1, the exploration of anterior segment was normal. Fundus examination revealed yellow lesion appearance at macula. Associated with a disruption of the presumed inner segment/outer segment junction (IS/0S) in the optical coherence tomography (OCT). After 1 month VA increased and OCT improved.Conclusions: Popper's maculopathy is an emerging disease that cause structural and functional affection of the outer retinal architecture. If we have a patient with bilateral vision loss with irregularity of the ellipsoid zone at the fovea, he should be asked specifically about poppers abuse.

A comparison of visual electrophysiology measures in optic neuropathy

Aims/Purpose: Our aim is to explore the inter‐relationship of clinical PVEP and PERG measurements with each other and the optic nerve structure in children investigated for possible optic neuropathies.Methods: ISCEV Standard PVEPs and PERGs to 50′ check widths to large 30 and standard 15 degree fields were reviewed from children suspected to have optic neuropathy of various pathology. Amplitudes and peak times of PERG P50, N95, the N95:P50 amplitude ratio, the amplitude of the N95 from baseline and at 30 ms from the P50‐N95 slope were measured. Spectralis OCT RNFL sector measures and macular ganglion cell volumes were collated.Results: PERG, PVEP with OCT measurements were available for 42 patients, (83 eyes) aged 6‐17 yrs. Those with abnormal PVEPs (33 eyes) had the most severe macular RGC volume loss (mean 0.26 mm3 in 3.45 mm) with mean LogMAR VA 0.52 (range − 0.01 to 1.00). These patients had inherited optic neuropathies, optic neuritis associated with MOGAD and RMMS. In contrast, patients with papilledema, such as associated with IIH, or presenting with headache and reduced vision and full discs had normal PVEPs. Mean VA LogMAR 0.23 (range − 1.0 to 0.9), and mean macular RGC volume 0.45 mm3 in 3.45 mm circle. N95:P50 amplitude ratios ranged from 1.83 to 0.44 in 30 degree fields and 2.16 to 0.36 in 15 degree fields. The N95:P50 amplitude ratios, slope at 30 ms and N95 from baseline correlated with macular RGC volume, but the best PERG discriminator (AUC 0.83) in the large field was the N95 slope measured at 30 ms. RNFL values were confounded by disc oedema in many cases.Conclusions: Pattern reversal VEPs were abnormal in all patients with severe RGC volume loss. The PERG measures correlate with macular RGC volume. RNFL was confounded by disc oedema, but was helpful in highlighting temporal sector thinning in optic neuritis and inherited optic atrophy such as LHOA.

Local ischaemia morphology in diabetics differs from healthy controls

Aims/Purpose: To evaluate local macular ischaemia morphology additional to global metrics in diabetic macular ischaemia (DMI) patients and healthy controls.Methods: The study was registered: DRKS‐ID DRKS00024399. Informed written consent was obtained from all participants. Seven DMI patients and seven patients after cataract surgery were included as healthy controls. 10 × 10° Heidelberg Spectralis OCT Angiography was recorded and divided to superficial/deep vascular complexes (SVC/DVC) following the inbuilt segmentation. Further processing was done in MATLAB R2022a. After binarization following Otsu's method for threshold determination, minimum distances to blood vessels were calculated for each pixel applying a sliding window. More than 30 μm distance to the next vessel was considered ischaemic. Morphology analysis of the resulting ischaemic lesions was conducted for SVC and DVC separately. The total ischaemic area; mean ischaemic area per lesion; area and circularity of the second largest ischaemic lesion—avoiding the foveal avascular zone—was extracted. Two‐sample Student t‐tests were performed testing differences of healthy controls and DMI patients in SVC and DVC for each of the four named metrics. Statistical significance was defined when p &lt; 0.05.Results: Analysing total ischaemic area, statistically significant differences were found for SVC and DVC data. Mean ischaemic area per lesion was significantly larger in DMI patients in SVC but not in DVC. The area of the largest ischaemic lesion avoiding FAZ was significantly larger in DMI patients in both SVC and DVC. Lesion circularity did not reveal significant differences.Conclusions: Supplementing reported global nonperfusion differences, local nonperfusion morphology differs significantly between DMI patients and healthy controls. Findings need to be replicated in a larger trial in the future. Research on structure function correlation in areas of nonperfusion will shed light on clinical implications.