Choroidal Thickness and Central Macular Thickness Measurements with Cirrus HD-OCT in Healthy.

AIM: This research was conducted to determine the normal values of choroidal thickness in healthy individuals and to evaluate the relationship between this thickness and age, gender, refraction, axial length and average macular thickness using OCT. MATERIAL AND METHOD: In the study, the right eyes of 400 healthy individuals (234 women, 166 men) between the ages of 4 and 70 years, who applied to the Department of Ophthalmology outpatient clinic for examination, were evaluated. RESULTS: Macular thickness, macular volume, and foveal thickness were found to be 249.12 ±21.32 µm, 9.98 ±0.5 µm3 and 280 ±13.45 µm, respectively. According to linear regression analysis, a negative correlation was detected between age and subfoveal choroidal thickness (p < 0.05). It was determined that foveal thickness, retinal volume and average retinal thickness were higher in men, and foveal thickness increased with age (p < 0.05). CONCLUSION: As a result of the research, it was determined that age is an important factor affecting choroidal thickness. It is thought that, in future, improving in vivo imaging of the choroid and measuring choroidal thickness using OCT will facilitate understanding of the pathophysiological basis of many ophthalmological diseases.

Clinical features of primary and compound forms of wide macular posterior staphyloma in high myopia.

BACKGROUND: To compare the ocular features of highly myopic eyes with posterior staphyloma of wide macular type according to its morphological complexity. METHODS: In this cross-sectional study, wide macular posterior staphyloma (WMPS) was classified into the primary (Curtin type I) and the compound (Curtin types VI to X) forms based on the configuration within the staphyloma. The grades of myopic maculopathy and the thicknesses of choroid and sclera were compared between the primary and compound forms of WMPS. RESULTS: A total of 154 eyes (103 patients) with primary WMPS and 65 eyes (49 patients) with compound WMPS were included. Eyes with compound WMPS had worse visual acuity (P = 0.001) and greater axial length (P < 0.001) than those with primary WMPS. Compared to primary WMPS, compound WMPS had a higher grade of myopic macular degeneration (P < 0.001) and a higher frequency of lamellar or full-thickness macular hole associated with myopic traction (21.5% vs. 10.4%; P = 0.028) and active or scarred myopic choroidal neovascularization (33.8% vs. 20.1%; P = 0.030). On swept-source optical coherence tomography, eyes with compound WMPS had significantly thinner choroid and sclera. CONCLUSIONS: The compound form of WMPS had more severe myopic macular changes and worse visual prognosis compared to the primary form of WMPS, and these were associated with more structural deformation in the posterior eyeball. Compound WMPS should be considered as an advanced form of staphyloma.

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

Purpose: 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. 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). Results: 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. Conclusions: 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. Translational Relevance: 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.

Predictive factors of age-related macular degeneration with poor response to three loading doses of anti-vascular endothelial growth factor.

PURPOSE: To evaluate the predictive factors of neovascular age-related macular degeneration (nAMD) with poor response to three loading doses of intravitreal bevacizumab (IVB). METHODS: A retrospective cohort study was performed on nAMD patients three loading IVB initial treatment. The patients were divided into two groups, without residual fluid on optical coherence tomography (OCT) images (Group 1) and with residual fluid (Group 2). Demographic data, OCT findings, and morphological features of macular neovascularization (MNV) in optical coherence tomography angiography (OCTA) were recorded. RESULTS: The study included one hundred thirty-six eyes of 120 patients (Group 1: n = 66 eyes, Group 2: n = 70 eyes). Central macular thickness, presence of intraretinal fluid, subretinal fluid, hyperreflective foci-band, pigment epithelial detachment (PED), and prechoroidal cleft were similar between the two groups. Pre-injection central choroidal thickness (CCT) was 214.17 ± 50.28 µm in Group 1 and 247.40 ± 60.55 µm in Group 2 (p = 0.021). PED width (p = 0.028) and PED area (p = 0.042) were statistically significantly higher in Group 1. When the morphology of MNV in OCTA was examined, branching (p = 0.736), loops (p = 0.442), peripheral arcade (p = 0.600), hypointense halo (p = 0.779), sea fan (p = 0.250), medusa (p = 0.255), pruned vascular tree pattern (p = 0.148), capillary fringe (p = 0.683) were similar in both groups. The presence of a closed circuit pattern was significantly higher in Group 2 (p = 0.028). CONCLUSION: Initial CCT and closed circuit pattern MNV were higher in IVB-resistant cases. It was observed that PEDs with large bases and areas responded significantly better to loading therapy. The presence of a closed-circuit pattern was an independent risk factor for poor response to loading therapy. Retrospectively registered. REGISTRATION NUMBER: 2011-KAEK-25 2023/05-08.

Analysis of Macular Vascularization Using Optical Coherence Tomography Angiography in Patients with Obstructive Sleep Apnea Syndrome: A Prospective Clinical Study.

Background and Objectives: Given the conflicting data available in the literature, this study aimed to investigate the impact of obstructive sleep apnea syndrome (OSAS) on the macular vascular density (VD) and perfusion density (PD). Materials and Methods: Based on the obstructive apnea-hypopnea index (OAHI), 61 prospectively recruited patients were assigned to either a control group (n = 12; OAHI < 5/h) or an OSAS group (n = 49; OAHI ≥ 5/h). The macular VD and PD of the superficial and deep capillary plexuses (SCP and DCP, respectively) were measured in the parafoveolar and perifoveolar areas using Zeiss PLEX Elite 9000 (6 × 6 mm). The values were compared between the control and OSAS groups. Results: Compared with the control group, the OSAS group demonstrated an increased VD of the DCP in the parafoveolar and perifoveolar areas and PD of the DCP in the perifoveolar area. No significant differences in either the macular VD or PD of the SCP were observed. There was no correlation between the OAHI and macular VD or PD. Conclusions: This study indicates that collateral vessel formation and possible retinal vasodilation occur in the DCP of patients with OSAS.

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

BACKGROUND: We 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. METHODS: A 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. RESULTS: The 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). CONCLUSION: While 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.

[Multimodal topographically oriented approach to the study of full-thickness macular holes]. / Mul'timodal'nyi topograficheski orientirovannyi podkhod k izucheniyu skvoznykh makulyarnykh razryvov.

PURPOSE: This article studies the relationship between structural changes according to the findings of optical coherence tomography (OCT) and OCT angiography (OCTA), microperimetry (MP), multifocal electroretinography (mfERG) parameters in topographically corresponding areas of the macular region in idiopathic full-thickness macular holes (FTMH). MATERIAL AND METHODS: OCT, OCTA, MP and mfERG were performed in 14 eyes with FTMH stages I-IV according to Gass. In 13 points at a distance of 0-2.5°, 2.5-5.0°, and 5.0-10.0° from the fixation point, the light sensitivity (LS), amplitude and latency of the P1 component were compared with the size of the hole, the area of cystic changes (CC) at the level of the inner nuclear layer (INL) and the outer plexiform layer and Henle fiber layer complex (OPL+HFL), vessel density in the superficial and deep capillary plexus (SCP and DCP). RESULTS: LS and P1 component amplitude were significantly reduced at a distance of up to 5.0° from the fixation point. LS correlates with the apical and basal diameter of the hole (R> -0.53), the area of CC in the INL (R> -0.62) and the OPL+HFL complex (R> -0.55), the density of vessels in the SCP at a distance of up to 2.5° from the fixation point (R>0.51) and in the DCP at a distance of up to 5° from the fixation point (R>0.49). The P1 amplitude correlates with the basal diameter of the hole (R= -0.38), the area of CC in the INL and the OPL+HFL complex (R> -0.33) and vessel density in the SCP (R=0.37) at a distance of up to 2.5° from the fixation point, as well as vessel density in the DCP at a distance of up to 5° from the fixation point (R=0.47). Vessel density in the DCP is significantly lower in the presence of CC in the retina (p<0.001). CONCLUSION: In FTMH, there is a relationship between bioelectrical activity and LS, and structural disorders, capillary perfusion in different layers of the retina. A multimodal topographically oriented approach allows studying the relationship between structural and functional parameters in individual points of the retina and can be used in monitoring of FTMH after surgical treatment.

The Effect of Hyperemesis Gravidarum on Macular Thickness, Corneal Thickness, and Intraocular Pressure in Pregnancy.

AIM: Physiological changes in intraocular pressure as well as in the cornea and macula may occur during pregnancy. Therefore, we decided to investigate the effect of hyperemesis gravidarum on macular thickness, corneal thickness and intraocular pressure (IOP). MATERIAL AND METHODS: A total of 110 people, 55 of whom were diagnosed with hyperemesis gravidarum and 55 of whom were in the control group, were included in the study. The inclusion criteria for the study were as follows: first trimester (8-14 weeks of gestation) pregnancy with positive fetal heartbeat and no history of systemic disease, no continuous use of medication, diagnosis of hyperemesis gravidarum (ketonuria and weight loss of more than 3 kilograms or 5% of body weight), body mass index (BMI) within normal limits, age between 18 and 40, no alcohol use or smoking. RESULTS: In the HG group compared to the control group, there was a difference between the CCT values of both the right and left eyes (p<0.01). There was a difference in both right and left IOP values in patients in the HG group compared to the control group (p<0.05), and there was no correlation between ketonuria scores and right and left eye CCT values, right and left eye macular thickness, and right and left eye pressure in patients diagnosed with HG (p>0.05). CONCLUSION: In hyperemesis gravidarum, changes occur in IOP, corneal thickness, and macular thickness. In ophthalmic examinations in the pregestational period, especially for women with systemic disease, it may be important for clinicians to take the necessary precautions in this regard.

ASSOCIATION OF MACULAR STRUCTURE WITH MICROPERIMETRY SENSITIVITY FOLLOWING VITRECTOMY FOR PROLIFERATE DIABETIC RETINOPATHY.

PURPOSE: To evaluate macular sensitivity using microperimetry in patients with proliferate diabetic retinopathy following vitrectomy and to investigate the relationship between the sensitivity and foveal microstructures with optical coherence tomography/angiography. METHODS: Eighty-four eyes of 84 patients with proliferative diabetic retinopathy, who were indicated for vitrectomy, had no intraocular surgery history 3 months preoperatively, and were able to ensure fundus examination after the vitrectomy, were included. A logMAR best-corrected visual acuity, macular sensitivity of microperimetry, macular retinal thickness, and macular vessel perfusion using optical coherence tomography/angiography were examined at 1 week, 1 month, and 3 months postoperatively. RESULTS: The logMAR best-corrected visual acuity and mean macular sensitivity of patients with proliferative diabetic retinopathy improved postoperatively (P < 0.05). There was a significant correlation between best-corrected visual acuity and mean sensitivity (P < 0.05). Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness in the 0 to 6 mm macular area (P < 0.05) and also significantly correlated with deep capillary plexus perfusion (P < 0.05). Fixation stability and mean macular sensitivity did not show any correlation with glycated hemoglobin, triglyceride, serum total cholesterol, carbamide, and creatinine and duration of diabetes mellitus (P > 0.05). CONCLUSION: Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness and deep capillary plexus perfusion for patients with proliferative diabetic retinopathy. The authors found that the visual performance of patients can be evaluated by the outer retinal thickness and deep capillary plexus perfusion, so optical coherence tomography/angiography examination can be an important prognostic factor for visual performance in patients.Clinical Trial Registration: This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn; Registration No.: ChiCTR2100043399).

Comparison of macular changes and visual outcomes between femtosecond laser-assisted cataract surgery and conventional phacoemulsification surgery for high myopic cataract patients.

BACKGROUND: To evaluate differences in log MAR best-corrected visual acuity (BCVA) improvement and postoperative central foveal thickness (CFT) and choroidal thickness (CT) changes between conventional phacoemulsification surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS) for high-myopia cataracts. METHODS: This was a retrospective and observational study. One hundred and two eyes of 102 patients with high-myopia cataracts were examined. CPS was performed in 54 eyes, and FLACS was performed in 48 eyes. All eyes underwent logMAR BCVA, CFT and CT of three different sectors preoperatively and one week and six months postoperatively. RESULTS: The logMAR BCVA improved significantly after surgery in both groups (both P < 0.001), but no difference was observed in BCVA improvement between the groups (P = 0.554). Moreover, no significant differences were reflected in the changes in CFT, nasal 1 mm CT or temporal 1 mm CT between the two groups, and only subfoveal choroidal thickness (SFCT) in the CPS group decreased significantly compared with that in the FLACS group at any postoperative time (P = 0.003 and 0.026). AL, preoperative logMAR BCVA, and CT of the three regions exhibited a notable correlation with postoperative BCVA (all P < 0.05) according to univariate logistic regression analysis. However, only the AL, preoperative logMAR BCVA and SFCT remained significant in the multivariate model. Postoperative logMAR BCVA revealed a positive correlation with AL and preoperative logMAR BCVA but a negative correlation with SFCT. CONCLUSIONS: FLACS was not superior to CPS in improving BCVA but had less impact on SFCT in the treatment of high-myopia cataracts. Eyes with a longer AL, worse preoperative logMAR BCVA and thinner SFCT had a high risk of worse postoperative BCVA.

Vision-Language Models for Feature Detection of Macular Diseases on Optical Coherence Tomography.

Importance: Vision-language models (VLMs) are a novel artificial intelligence technology capable of processing image and text inputs. While demonstrating strong generalist capabilities, their performance in ophthalmology has not been extensively studied. Objective: To assess the performance of the Gemini Pro VLM in expert-level tasks for macular diseases from optical coherence tomography (OCT) scans. Design, Setting, and Participants: This was a cross-sectional diagnostic accuracy study evaluating a generalist VLM on ophthalmology-specific tasks using the open-source Optical Coherence Tomography Image Database. The dataset included OCT B-scans from 50 unique patients: healthy individuals and those with macular hole, diabetic macular edema, central serous chorioretinopathy, and age-related macular degeneration. Each OCT scan was labeled for 10 key pathological features, referral recommendations, and treatments. The images were captured using a Cirrus high definition OCT machine (Carl Zeiss Meditec) at Sankara Nethralaya Eye Hospital, Chennai, India, and the dataset was published in December 2018. Image acquisition dates were not specified. Exposures: Gemini Pro, using a standard prompt to extract structured responses on December 15, 2023. Main Outcomes and Measures: The primary outcome was model responses compared against expert labels, calculating F1 scores for each pathological feature. Secondary outcomes included accuracy in diagnosis, referral urgency, and treatment recommendation. The model's internal concordance was evaluated by measuring the alignment between referral and treatment recommendations, independent of diagnostic accuracy. Results: The mean F1 score was 10.7% (95% CI, 2.4-19.2). Measurable F1 scores were obtained for macular hole (36.4%; 95% CI, 0-71.4), pigment epithelial detachment (26.1%; 95% CI, 0-46.2), subretinal hyperreflective material (24.0%; 95% CI, 0-45.2), and subretinal fluid (20.0%; 95% CI, 0-45.5). A correct diagnosis was achieved in 17 of 50 cases (34%; 95% CI, 22-48). Referral recommendations varied: 28 of 50 were correct (56%; 95% CI, 42-70), 10 of 50 were overcautious (20%; 95% CI, 10-32), and 12 of 50 were undercautious (24%; 95% CI, 12-36). Referral and treatment concordance were very high, with 48 of 50 (96%; 95 % CI, 90-100) and 48 of 49 (98%; 95% CI, 94-100) correct answers, respectively. Conclusions and Relevance: In this study, a generalist VLM demonstrated limited vision capabilities for feature detection and management of macular disease. However, it showed low self-contradiction, suggesting strong language capabilities. As VLMs continue to improve, validating their performance on large benchmarking datasets will help ascertain their potential in ophthalmology.

Acute macular neuroretinopathy following Valsalva manoeuvre: an insight into the pathophysiology.

Acute macular neuroretinopathy (AMN) affects the outer retina and is most likely induced by non-inflammatory ischaemia of the retinal deep capillary plexus and choriocapillaris. A man in his early 20s developed Valsalva retinopathy following weightlifting at the gym and presented with blurring of vision in the left eye 1 month after the initial retinal haemorrhages had resolved. A diffuse, purplish, donut-shaped, perifoveal lesion was seen on funduscopy and was well defined by an optical coherence tomography angiography (OCTA) en face image in the left eye. Outer retinal changes on optical coherence tomography (OCT) and a dense co-localised scotoma on a visual field (VF) examination confirmed the diagnosis of AMN, and the patient was started on a tapering dose of oral steroids. Improvement was seen in OCT, OCTA and VF during the 6-month follow-up visit. The use of OCTA en face imaging enabled the accurate identification of the lesion in the affected layers of the retina.

Linking Vascular Structure and Function: Image-Based Virtual Populations of the Retina.

Purpose: This study explored the relationship among microvascular parameters as delineated by optical coherence tomography angiography (OCTA) and retinal perfusion. Here, we introduce a versatile framework to examine the interplay between the retinal vascular structure and function by generating virtual vasculatures from central retinal vessels to macular capillaries. Also, we have developed a hemodynamics model that evaluates the associations between vascular morphology and retinal perfusion. Methods: The generation of the vasculature is based on the distribution of four clinical parameters pertaining to the dimension and blood pressure of the central retinal vessels, constructive constrained optimization, and Voronoi diagrams. Arterial and venous trees are generated in the temporal retina and connected through three layers of capillaries at different depths in the macula. The correlations between total retinal blood flow and macular flow fraction and vascular morphology are derived as Spearman rank coefficients, and uncertainty from input parameters is quantified. Results: A virtual cohort of 200 healthy vasculatures was generated. Means and standard deviations for retinal blood flow and macular flow fraction were 20.80 ± 7.86 µL/min and 15.04% ± 5.42%, respectively. Retinal blood flow was correlated with vessel area density, vessel diameter index, fractal dimension, and vessel caliber index. The macular flow fraction was not correlated with any morphological metrics. Conclusions: The proposed framework is able to reproduce vascular networks in the macula that are morphologically and functionally similar to real vasculature. The framework provides quantitative insights into how macular perfusion can be affected by changes in vascular morphology delineated on OCTA.

The long-term influence of perinatal factors on macular morphology and vessel density in preterm children.

BACKGROUND: Increased survival rate of extremely preterm children is associated with a higher risk of retinopathy of prematurity (ROP) and long-term sequelae, which implicate retinal changes. PURPOSE: To assess an influence of perinatal characteristics on morphology and retinal vascularity of the macula in preterm children. METHODS: A cohort of 123 preterm children at the age of 10.5 years (IQR: 8.12-12.77) was prospectively assessed. Optical coherence tomography angiography (OCTA) was performed using RTVueXR Avanti. Foveal thickness, parafoveal thickness, size of foveal avascular zone (FAZ), superficial and deep vessel density, central choroidal thickness (CCT) were analyzed. The associations between OCTA results and perinatal factors, including the presence of ROP and therapy requirements were assessed in preterm children. RESULTS: Significantly smaller FAZ, higher foveal thickness and vessel density were noted in children with ROP, Respiratory Distress Syndrome, Bronchopulmonary Dysplasia, required erythropoietin, transfusion or steroids. Foveal thickness was increased in children with ROP (p < 0.001) and following laser treatment (p < 0.05). Thinner CCT was noted in children with a history of sepsis (p < 0.05) and ROP required treatment (p < 0.05). Pregnancy bleeding was associated with higher superficial foveal vessel density (p < 0.05) and smaller FAZ (p < 0.05). CONCLUSION: Neonatal factors have a huge impact on retinal development, but the role of prenatal factors should not be neglected in preterm children.

Choroidal and central macular thickness before and after treatment in post fever retinitis.

PURPOSE: To study the choroidal thickness (CT) and central macular thickness (CMT) in post-fever retinitis (PFR) and their correlation with visual acuity and treatment. METHODS: A retrospective, observational study of patients presenting with PFR from 2013 to 2021 and with spectral domain optical coherence tomography (SD-OCT) (Heidelberg®, SpectralisTM, Heidelberg, Germany) images were included. The CT and CMT were measured at presentation and at the final visit. The CT was measured subfoveally and at points 2000 µm superior, inferior, medial, and lateral from the fovea using the caliper tool. RESULTS: Seventy-nine eyes of 65 patients were included for this study. The mean age was 39.03 (±16.00) years with female preponderance of 53.84% (n = 35). Mean follow-up duration was 30 days. Mean CT at presentation and at follow-up was 254.12 µm and 241.51 µm, respectively. CT was decreased in majority of the eyes 67.1% (n = 53) from their baseline value. Mean CMTs at presentation and final visit were 454.8 µm and 223.7 µm, respectively. Best corrected visual acuity had a positive correlation with CMT (r = 0.340; P = 0.002) and negligible correlation with CT. A significant decrease in the mean CT was noted in patients who received doxycycline either alone or in combination with a steroid as compared to those who did not receive any treatment (P < 0.001). The significance of which is unknown presently. CONCLUSION: CMT has a greater role in determining the final visual outcome than CT. CT can be reduced post-treatment with no effect on vision.

DIRECTIONAL OPTICAL COHERENCE TOMOGRAPHY IMAGING OF MACULAR PATHOLOGY.

PURPOSE: To survey the impact of directional reflectivity on structures within optical coherence tomography images in retinal pathology. METHODS: Sets of commercial optical coherence tomography images taken from multiple pupil positions were analyzed. These directional optical coherence tomography sets revealed directionally reflective structures within the retina. After ensuring sufficient image quality, resulting hybrid and composite images were characterized by assessing the Henle fiber layer, outer nuclear layer, ellipsoid zone, and interdigitation zone. Additionally, hybrid images were reviewed for novel directionally reflective pathological features. RESULTS: Cross-sectional directional optical coherence tomography image sets were obtained in 75 eyes of 58 patients having a broad range of retinal pathologies. All cases showed improved visualization of the outer nuclear layer/Henle fiber layer interface, and outer nuclear layer thinning was, therefore, more apparent in several cases. The ellipsoid zone and interdigitation zone also demonstrated attenuation where a geometric impact of underlying pathology affected their orientation. Misdirected photoreceptors were also noted as a consistent direction-dependent change in ellipsoid zone reflectivity between regions of normal and absent ellipsoid zone. CONCLUSION: Directional optical coherence tomography enhances the understanding of retinal anatomy and pathology. This optical contrast yields more accurate identification of retinal structures and possible imaging biomarkers for photoreceptor-related pathology.

Macular and peripapillary vascular parameters in the fellow eyes of unilateral primary congenital glaucoma: a comparative study.

PURPOSE: To study the fellow eyes of patients with unilateral primary congenital glaucoma (PCG) using optical coherence tomography angiography (OCTA) and compare them to normal age- and refractive error-matched healthy controls. METHODS: Using OCTA, the foveal avascular zone (FAZ) area, cup:disk ratio, vessel density (VD) of the optic nerve head (ONH) and peripapillary area and the macular VD in superficial (SCP) and deep vascular complexes in both 3 mm and 6 mm scans of both groups were compared. Clinical data included best-corrected visual acuity (BCVA), cycloplegic refraction, intraocular pressure (IOP), anterior and posterior segments examination findings, including ONH cup:disk ratio. RESULTS: A total of 48 eyes of 48 children (24 eyes in each group) were included. There was no difference in the mean retinal nerve fiber layer thickness, cup:disk ratio, baseline visual acuity, or spherical equivalent between groups (P > 0.05). In the 3 mm macular scan, the VD of the SCP at the fovea was significantly higher in the PCG group compared to controls (P = 0.04). In the ONH scans, there was a significantly reduced inside the disk VD in the PCG group compared to controls (P = 0.03). There was no significant difference in other macular and ONH vascular parameters between groups (P > 0.05). CONCLUSIONS: In our study cohort, there was no difference in most of the macular and ONH vascular parameters between groups. However, the fellow eyes of PCG patients exhibited higher VD of the SCP at the fovea and reduced inside the disk VD compared with control eyes.