High-resolution Optical Coherence Tomography Research Articles

Vitreomacular traction: diagnostics, natural course, treatment decision and guideline recommendations

Vitreomacular traction is atractive foveolar adhesion of the posterior vitreous limiting membrane, resulting in pathological structural alterations of the vitreomacular interface. This must be differentiated from physiological vitreomacular adhesion, which exhibits acompletely preserved foveolar depression. Symptoms depend on the severity of the macular changes and typically include reduced visual acuity, reading problems and metamorphopsia. High-resolution spectral domain optical coherence tomography (SDOCT) imaging enables classification of the sometimes only subtle morphological changes. If pronounced vitreomacular traction is accompanied by epiretinal gliosis and alterations to the outer retina, it is referred to as avitreomacular traction syndrome. Vitreomacular traction has ahigh probability of spontaneous resolution within 12months. Therefore, treatment should only be carried out in cases of undue suffering of the patient and with symptoms during bilateral vision and alack of spontaneous resolution. In addition to pars plana vitrectomy, alternative treatment options, such as intravitreal injection of ocriplasmin and pneumatic vitreolysis are discussed for vitreomacular traction with an associated macular hole; however, ocriplasmin is no longer available in Germany. The best anatomical results in comparative investigations were achieved by vitrectomy. Pneumatic vitreolysis is controversially discussed due to the increased risk of retinal tears. In one of the current S1guidelines of the German ophthalmological societies evidence-based recommendations for the diagnostics and treatment of vitreomacular traction are summarized.

Characteristic deviations of the optic disc and macula in optic nerve hypoplasia based on OCT.

The purpose of this study was to evaluate the optic disc and macula in a large cohort of patients with different severity of optic nerve hypoplasia (ONH) using high-resolution spectral domain optical coherence tomography (SD-OCT). In total, 36 patients (52 ONH eyes and 17 fellow eyes in unilateral cases) and 45 healthy right eyes from 45 controls were evaluated. All patients underwent an examination to confirm the diagnosis. SD-OCT images of the disc and macula were obtained and analysed both quantitatively and qualitatively. OCT in ONH eyes demonstrated a shorter disc diameter (1061 ± 375 μm vs. 1751 ± 221 μm, p < 0.001), shallower mean cup depth (427 ± 171 μm vs. 551 ± 152 μm, p = 0.01), thinner ganglion cell complex (GCC) perifoveally (47.3 ± 13.0 μm, 60.8 ± 6.0 μm, p < 0.001) and reduced foveal depth (61 ± 36 μm, 119 ± 19 μm, p < 0.001) compared to control eyes. Qualitative analysis showed that 1/3rd of ONH eyes lacked signs of an optic cup, and 2/3rd had reduced or no sign of a foveal pit. Fellow eyes had shorter disc diameter (1446 ± 404 μm vs. 1751 ± 221 μm, p = 0.004) and reduced foveal depth (93 ± 27 μm vs. 119 ± 19 μm, p < 0.001) but similar GCC thickness (60.8 ± 7.1 μm vs. 60.8 ± 6.0 μm, p = 0.738) compared to controls. Disc diameter showed the best correlation with visual acuity in ONH eyes (ρ = 0.517, p < 0.001). ONH eyes have reduced GCC thickness and reduced or no foveal pit. Fellow eyes in presumed unilateral cases have a smaller disc diameter and reduced foveal depth compared to controls, suggesting the possibility of subclinical/mild disease. However, GCC thickness was normal. The correlation between structure and visual function is not always straightforward.

Phase-sensitive Optical Coherence Tomography reveals droplet penetration into a powder bed

Understanding the mixing behavior that unfolds when liquid droplets impact on powder beds requires a sub-surface dynamic imaging method that provides high spatial and temporal resolution. In this study, a high-resolution phase-sensitive optical coherence tomography (PhS-OCT) technique was introduced to provide in-depth insights into the interaction of droplets and powder beds. A theoretical model correlating changes in the optical path differences (OPD) of the OCT signal with physical properties of the powder bed was presented. Experiments were conducted on three powders with median particle diameters, i.e., the size corresponding to the 50th percentile of the cumulative volume distribution, of 3 µm (mannitol), 4 µm (mannitol) and 109 µm (SV010). Water and ethanol droplets were used to illustrate the technique. The results demonstrated that OPD maps can qualitatively resolve the liquid-powder mixture region, both temporally and spatially, as the droplet diffuses into the powder bed, allowing for a quantitative description of diffusion behavior. A comparison of lactose and mannitol powder samples revealed varying diffusion rates, potentially attributed to differences in porosity, particle size, and agglomeration. Additionally, water and ethanol droplets exhibited significantly different (p = 0.005) diffusion profiles for the same powder properties. In general, the findings indicate the potential of the proposed PhS-OCT technique for evaluating the mixing behavior of multi-phase mixtures, holding promise in applications such as pharmaceutical drug formulations and additive manufacturing.

Creating realistic anterior segment optical coherence tomography images using generative adversarial networks

AimsTo develop a generative adversarial network (GAN) capable of generating realistic high-resolution anterior segment optical coherence tomography (AS-OCT) images.MethodsThis study included 142 628 AS-OCT B-scans from the American University of...

Acute alcohol consumption modulates corneal biomechanical properties as revealed by optical coherence elastography

Acute alcohol ingestion has been found to impact visual functions, including eye movement, but its effects on corneal biomechanical properties remain unclear. This study aimed to investigate the influence of acute alcohol consumption on corneal biomechanical properties using optical coherence elastography (OCE). An air-coupled ultrasound transducer induced elastic waves in mice corneas in vivo, and a high-resolution phase-sensitive optical coherence tomography (OCT) system tracked the mechanical waves to quantify the elastic wave speed. In vivo measurements were performed on three groups of age- and gender-matched mice: control, placebo (administered saline), and alcohol (administered ethanol) groups. Longitudinal measurements were conducted over a one-hour period to assess acute temporal changes in wave speeds, which are associated with inherent biomechanical properties of the cornea. The results showed a significant decrease in wave speed for the alcohol group after 10 min of ingestion in comparison to pre-ingestion values (p = 0.0096), whereas the temporal wave speed changes for the placebo group were statistically insignificant (p = 0.076). In contrast, the control group showed no significant changes in elastic wave speed and corneal thickness. Furthermore, a significant difference was observed between the wave speeds of the placebo and alcohol groups at each measurement time point between 10 and 50 min (p < 0.05), though both groups exhibited a similar trend in corneal thickness change. The findings of this study have important implications for clinical assessments and research in corneal disorders, highlighting the potential of OCE as a valuable tool for evaluating such changes.

A Case Report of Temporal Macular Thinning Associated with Alport Syndrome

Purpose: To report a case of severe of severe temporal macular thinning in a patient with Alport syndrome. Bilateral temporal thinning is rarely associated with any other systemic conditions, so it is important that ophthalmologists be aware of the significance of this finding and refer for further internal medicine evaluation appropriately. Methods: Clinical examination and multimodal imaging are provided from a clinic visit one month after inpatient treatment for a hypertensive crisis associated with renal failure. Results: The 19-year-old patient had resolving hypertensive retinopathy. High-resolution optical coherence tomography (OCT) confirmed that he had temporal thinning indices (TTIs) consistent with his underlying clinical diagnosis of Alport syndrome. Conclusion: This case report emphasizes the important role of OCT as a commonly available noninvasive retinal imaging modality that can readily demonstrate the temporal macular thinning that is characteristic of Alport syndrome and just a few other conditions. OCT can be an attractive alternative to the much more invasive renal biopsy testing for Alport syndrome when genetic testing is ambiguous or when renal biopsy is considered too risky for the patient.

Corneal Microaneurysm-A Vascular Feature of Conjunctival Squamous Intraepithelial Neoplasia.

The diagnosis of conjunctival squamous intraepithelial neoplasia (CSIN) can be difficult because of the heterogeneous appearance. Despite established risk factors and diagnostic support by high-resolution optical coherence tomography (hrOCT) and indocyanine green angiography (ICGA), the only reliable diagnostic method is a histological work-up. This case report is the first to describe corneal microaneurysms in CSIN as a vascular feature for conjunctival tumor angiogenesis. An 84-year-old male patient was referred with a suspected diagnosis of pterygium. Biomicroscopic examination revealed a whitish epithelial lesion of conjunctival origin with centripetal corneal growth and extension over 5 limbal hours. Intralesional vascularization showed highly altered morphology with aneurysmal changes. After imaging with hrOCT and ICGA, excision was performed in a "no-touch double-freeze and thaw" technique, followed by histological and immunohistochemical work-up. hrOCT showed an epithelial, hyperreflective lesion with a maximum thickness of 272 µm and sharp central border. ICGA confirmed active perfusion and partial thrombosis of the aneurysmal terminal vascular buds dilated to 405 μm with early dye leakage within the first minute. Histological examination confirmed the clinical diagnosis of CSIN with focal high-grade dysplasia. Postoperatively, there was no recurrence during the observation period of 5 months. Intralesional terminal microaneurysms are a feature of tumor angiogenesis in CSIN. The relevance and frequency of this potential new risk factor for malignancy should be investigated in further studies.

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.

Therapeutic Response to Treatment of a Papillomatous Ocular Surface Squamous Neoplasia With Intramuscular Human Papillomavirus Vaccine.

The purpose of this study was to describe the response of a papillomatous ocular surface squamous neoplasia (OSSN) to the intramuscular (IM) 9-valent human papillomavirus (HPV) vaccine after failed medical and surgical interventions. A 79-year-old White man with a conjunctival lesion underwent a biopsy which revealed OSSN and positivity for high-risk HPV. Initially treated with medical therapy and surgical excisions, the patient developed a recurrence and refused further surgery. He was given 4 doses of IM HPV vaccine at the 6-week interval. A dramatic reduction in lesion size and reduced epithelial thickening and hyperreflectivity was noted on slitlamp examination and high-resolution anterior segment optical coherence tomography after receiving the IM HPV vaccine. Although lesion size was markedly reduced, the therapy did not achieve total resolution, resulting in further treatment with topical 1% 5-fluorouracil (5-FU) eye drops and later 0.04% mitomycin C eye drops. The patient then elected to discontinue further treatment and solely observe. This case report adds to the growing literature demonstrating the potential therapeutic use of vaccines in cancer treatment. Although HPV vaccination is currently approved for prophylaxis, the use of HPV vaccines as a therapeutic option for various HPV-mediated diseases, including OSSN, should be further explored. The HPV vaccine yielded significant initial improvement in this patient who refused further surgical interventions. The use of IM HPV vaccine as an adjunctive treatment of papillomatous OSSN may represent a potential therapeutic option in cases refractory to standard treatment modalities.

Boucher-Neuhauser Syndrome: Chorioretinal Changes in a Single Case Over Time.

To describe chorioretinal changes in a single case of Boucher-Neuhauser Syndrome (BNHS) over 45 years of follow-up. Methods: Retrospective chart review was performed. Color fundus photography from 1977 to 2003 was obtained and digitized. Current fundus photography was obtained with widefield imaging. High-resolution spectral-domain optical coherence tomography (OCT) was performed. Genetic analysis was performed using an inherited retinal disorders panel. Results: Fundus examination demonstrated central chorioretinal atrophy with sclerotic choroidal vessels. Short posterior ciliary arteries became more prominent and tortuous over time. Mid-peripheral atrophy extends to the equator and demonstrates a scalloped pattern with islands of atrophy intervening with areas of normal retina. The far periphery remained minimally affected. High-resolution OCT demonstrated outer retinal atrophy and choriocapillaris loss. Genetic testing showed a homozygous variant for PNPLA6 and a heterozygous variant for TYRP1. Conclusion: Chorioretinal changes in BNHS vary in onset and severity. It is important to diagnose this condition in order to begin timely management of visual and systemic sequelae.

Glucose tolerance and insulin resistance/sensitivity associate with retinal layer characteristics: the LIFE-Adult-Study

Aims/hypothesisAs the prevalence of insulin resistance and glucose intolerance is increasing throughout the world, diabetes-induced eye diseases are a global health burden. We aim to identify distinct optical bands which are closely related to insulin and glucose metabolism, using non-invasive, high-resolution spectral domain optical coherence tomography (SD-OCT) in a large, population-based dataset.MethodsThe LIFE-Adult-Study randomly selected 10,000 participants from the population registry of Leipzig, Germany. Cross-sectional, standardised phenotyping included the assessment of various metabolic risk markers and ocular imaging, such as SD-OCT-derived thicknesses of ten optical bands of the retina. Global and Early Treatment Diabetic Retinopathy Study (ETDRS) subfield-specific optical retinal layer thicknesses were investigated in 7384 healthy eyes of 7384 participants from the LIFE-Adult-Study stratified by normal glucose tolerance, prediabetes (impaired fasting glucose and/or impaired glucose tolerance and/or HbA1c 5.7–6.4% [39–47 mmol/mol]) and diabetes. The association of optical retinal band characteristics with different indices of glucose tolerance (e.g. fasting glucose, area under the glucose curve), insulin resistance (e.g. HOMA2-IR, triglyceride glucose index), or insulin sensitivity (e.g. estimated glucose disposal rate [eGDR], Stumvoll metabolic clearance rate) was determined using multivariable linear regression analyses for the individual markers adjusted for age, sex and refraction. Various sensitivity analyses were performed to validate the observed findings.ResultsIn the study cohort, nine out of ten optical bands of the retina showed significant sex- and glucose tolerance-dependent differences in band thicknesses. Multivariable linear regression analyses revealed a significant, independent, and inverse association between markers of glucose intolerance and insulin resistance (e.g. HOMA2-IR) with the thickness of the optical bands representing the anatomical retinal outer nuclear layer (ONL, standardised β=−0.096; p<0.001 for HOMA2-IR) and myoid zone (MZ; β=−0.096; p<0.001 for HOMA2-IR) of the photoreceptors. Conversely, markers of insulin sensitivity (e.g. eGDR) positively and independently associated with ONL (β=0.090; p<0.001 for eGDR) and MZ (β=0.133; p<0.001 for eGDR) band thicknesses. These global associations were confirmed in ETDRS subfield-specific analyses. Sensitivity analyses further validated our findings when physical activity, neuroanatomical cell/tissue types and ETDRS subfield categories were investigated after stratifying the cohort by glucose homeostasis.Conclusions/interpretationAn impaired glucose homeostasis associates with a thinning of the optical bands of retinal ONL and photoreceptor MZ. Changes in ONL and MZ thicknesses might predict early metabolic retinal alterations in diabetes.Graphical

Chronic inflammation as a proposed risk factor for ocular surface squamous neoplasia

Chronic inflammation is a predisposing factor for metaplastic changes and ultimately dysplasia. We describe cases of OSSN occurring in the setting of chronic ocular surface inflammation. Sixteen eyes from 14 individuals were included from one ocular oncology clinic between 2010 and 2023. Patients presented with ocular surface squamous neoplasia (OSSN) in the setting of chronic inflammation. The diagnosis of OSSN was made using anterior segment high-resolution optical coherence tomography (HR-OCT) and confirmed by histopathological analysis in all cases. Median age on presentation was 61 [IQR 47.5-69.2] years. Eleven (86%) individuals were male and five (36%) identified as White Hispanic. Ten eyes were referred with ocular surface diagnoses including pannus (n=4), scarring (n=3), pterygium (n=2), and herpetic keratitis (n=1). Only six eyes were referred as possible neoplasia. All individuals had a history of ocular surface inflammation. The most common inflammatory conditions were ocular rosacea (seven individuals) and atopic keratoconjunctivitis (AKC) (five individuals). Two individuals were found to have bilateral OSSN, one in the setting of ocular rosacea and the other in the setting of AKC. All 16 eyes from 14 individuals were suspected to have OSSN based on HR-OCT findings which guided the location of the incisional biopsies that subsequently confirmed histopathological diagnosis in all cases. OSSN may arise in the setting of chronic inflammation on the ocular surface. Identification of the tumor can be challenging in these cases, and HR-OCT can be a key diagnostic tool in detecting OSSN.

Comparative In Vivo Imaging of Retinal Structures in Tree Shrews, Humans, and Mice.

Rodent models, such as mice and rats, are commonly used to examine retinal ganglion cell damage in eye diseases. However, as nocturnal animals, rodent retinal structures differ from primates, imposing significant limitations in studying retinal pathology. Tree shrews (Tupaia belangeri) are small, diurnal paraprimates that exhibit superior visual acuity and color vision compared with mice. Like humans, tree shrews have a dense retinal nerve fiber layer (RNFL) and a thick ganglion cell layer (GCL), making them a valuable model for investigating optic neuropathies. In this study, we applied high-resolution visible-light optical coherence tomography to characterize the tree shrew retinal structure in vivo and compare it with that of humans and mice. We quantitatively characterize the tree shrew's retinal layer structure in vivo, specifically examining the sublayer structures within the inner plexiform layer (IPL) for the first time. Next, we conducted a comparative analysis of retinal layer structures among tree shrews, mice, and humans. We then validated our in vivo findings in the tree shrew inner retina using ex vivo confocal microscopy. The in vivo and ex vivo analyses of the shrew retina build the foundation for future work to accurately track and quantify the retinal structural changes in the IPL, GCL, and RNFL during the development and progression of human optic diseases.

Material Analysis of Explanted Calcified Silicone Intraocular Lenses in Association with Asteroid Hyalosis.

The aim of this study was to analyze posterior surface opacification in explanted silicone intraocular lenses (IOLs) with clinicopathologic correlation to asteroid hyalosis. In a laboratory setup, 12 explanted silicone IOLs underwent laboratory analyses, including light microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy for elemental composition (EDX). Relevant clinical data were obtained for each case, including gender, age at IOL implantation, dates of implantation and explantation, as well as history of neodymium-dopped yttrium aluminum garnet (Nd:YAG) laser treatments or other opacification removal attempts. High-resolution optical coherence tomography (OCT) images were obtained in vitro with an anterior segment OCT device (Anterion, Heidelberg Engineering, Heidelberg, Germany). Calcification located at the posterior optic surface of each lens was identified through SEM and EDX analyses, revealing deposits composed of hydroxyapatite. In all cases, IOL polishing using Nd:YAG laser had been attempted prior to IOL exchange. The clinical functional data showed that this type of IOL opacity led to increase in straylight and subjective symptoms of glare. Silicone IOLs can develop posterior surface calcification in eyes with asteroid hyalosis. There are mechanical techniques of cleaning the IOL surface but in many cases, IOL explantation is the only sustainable way to reduce the patients' straylight levels and glare symptoms. Due to the risk of posterior surface calcification, silicone IOL implantation should be avoided in eyes with asteroid hyalosis.

Multimodal imaging of acute fovealitis with angular sign of Henle fiber layer hyperreflectivity (ASHH): Report of a case and review of the literature

Acute retinal pigment epitheliitis (ARPE) is a rare and transient macular disorder that was first described by Krill and Deutman in 1972. Later, Gerardo Ledesma-Gil and Spaide described a novel disease named acute fovealitis in 2022. According to them, this entity was different from ARPE on the basis of distinct features found in high-resolution optical coherence tomography (OCT) imaging. Angular sign of Henle fiber layer hyperreflectivity (ASHH) is a newly described terminology that is caused by an acute insult to photoreceptor compartments. In this article, we report a case that has both the ophthalmoscopic and OCT features of acute fovealitis as described in the literature, with the presence of ASHH in the acute stage, which resolves on its own rapidly along with the symptoms without any intervention.

OCT angiography in the monitoring of vaginal health.

Fractional-pixel CO2 laser therapy shows promise for treating the genitourinary syndrome of menopause (GSM). Nevertheless, it remains controversial in the field of female pelvic medicine. This is due to the inherent difficulties in obtaining noninvasive biopsies to evaluate the treatment's efficacy and safety objectively. To address this challenge, we developed a noninvasive intravaginal optical coherence tomography (OCT)/OCT angiography (OCTA) endoscopic system, whose probe features a shape identical to the laser treatment probe. This system can provide high-resolution OCT images to identify the microstructure of vaginal tissue and visualize the vasculature network in vivo. We conducted clinical research on 25 post-menopausal patients with GSM. OCT/OCTA scans were acquired at four different locations of the vagina (distal anterior, distal posterior, proximal anterior, and proximal posterior) during the whole laser treatment session. A U-Net deep learning model was applied to segment the vaginal epithelium for assessing vaginal epithelial thickness (VET). Blood vessel density and VET were quantified to monitor the efficacy of fractional-pixel CO2 laser therapy. Statistical correlation analyses between these metrics and other clinical scores were conducted, validating the utility of our system. This OCT/OCTA endoscopic system has great potential to serve as a noninvasive biopsy tool in gynecological studies to screen, evaluate, and guide laser treatment for GSM.

Unveiling the Hidden: Early Manifestations of Extensive Macular Atrophy with Pseudodrusen-like appearance.

To describe novel microperimetry and imaging findings in two patients affected by extensive macular atrophy with pseudodrusen-like appearance (EMAP) without signs of retinal pigment epithelium (RPE) atrophy. Case series. Both patients underwent mesopic and dark-adapted two-color scotopic microperimetry, followed by multimodal imaging assessment including ultra-widefield photography, fundus autofluorescence (AF), high-resolution optical coherence tomography (Hi-Res OCT), OCT angiography and high-magnification module (HMM). Albeit normal visual acuity, both patients had a significant reduction of retinal sensitivity - especially under scotopic cyan conditions. One patient had macular pigment abnormalities, while the combination of blue and near-infrared AF modalities highlighted different patterns of pseudodrusen-like lesions.Of notice, Hi-Res OCT revealed a marked separation between the RPE and Bruch's membrane, containing a hyperreflective material with two different reflectivities. OCT angiography excluded the presence of macular neovascularization and documented several choriocapillaris flow voids. HMM images showed severe alteration of photoreceptors' mosaic in the perifovea. Our comprehensive assessment of two stage 1 EMAP patients revealed a predominant damage of perifoveal rods over areas of RPE-Bruch's membrane separation. These findings underscore the importance of basal laminar deposits in the initial stages of EMAP, contributing to a deeper understanding of its underlying mechanisms.

It Is All About the Angle: A Clinical and Optical Coherence Tomography Comparison of Corneal Ocular Surface Squamous Neoplasia and Corneal Pannus.

The aim of this study was to compare clinical characteristics and high-resolution optical coherence tomography (HR-OCT) findings between corneal ocular surface squamous neoplasia (OSSN) and corneal pannus. Retrospective study of 9 individuals, 3 with lesions histologically confirmed to be OSSN, 3 with lesions histologically confirmed to be pannus, 1 with lesions histologically confirmed to be OSSN followed by pannus, and 2 with long-standing, nonchanging lesions clinically diagnosed as pannus. All individuals presented to the Miami Veterans Affairs Medical Center eye clinic or Bascom Palmer Eye Institute between 2015 and 2023. Clinical characteristics and HR-OCT findings were evaluated and compared. Mean age of the population was 72.8 ± 5.1 years, 100% self-identified as male, 100% as White, and 11.1% as Hispanic. Clinically, all lesions appeared as whitish, opalescent, variably vascularized opacities extending from the limbus. None of the OSSN cases had vessels that extended to the border, whereas 4 cases of pannus (67%) had at least 1 vessel that reached the border. On HR-OCT, epithelial hyperreflectivity was observed in all cases of OSSN and pannus. Epithelial thickening was observed in all cases of OSSN, but in none of the cases of pannus. An important distinction between the 2 groups was the transition between normal and abnormal epithelium. All cases of OSSN had a vertical transition, whereas all cases of pannus had an angled transition. Corneal OSSN and corneal pannus can both present with clinical findings of an opalescent lesion and may have overlapping findings on HR-OCT. Although both entities may show epithelial hyperreflectivity on HR-OCT, OSSN demonstrates an abrupt transition at a vertical, 90 degrees angle perpendicular to the Bowman layer, whereas pannus appears as an angled transition around 45 degrees. Therefore, the angle of transition between normal and abnormal epithelium can be useful in distinguishing between the 2 entities.

Atrophic Lesions Associated with Age-Related Macular Degeneration: High-Resolution versus Standard OCT

ObjectiveThe objective of this study was to determine whether high-resolution optical coherence tomography (HR-OCT) could enhance the identification and classification of atrophic features in age-related macular degeneration (AMD) compared to standard resolution OCT. DesignProspective, observational, cross-sectional study. SubjectsThe study included 60 eyes from 60 patients over the age of 60 with a diagnosis of AMD. MethodsThe participants underwent volume OCT scanning using HR-OCT and standard resolution OCT devices. Trained graders reviewed and graded the scans, identifying specific regions of interest for subsequent analysis. Main Outcome MeasuresThe study focused on identifying and classifying complete retinal pigment epithelium and outer retinal atrophy (cRORA), incomplete RORA (iRORA), and other non-atrophic AMD features. Additionally, qualitative and quantitative features associated with atrophy were assessed. ResultsThe agreement among readers for classifying atrophic lesions was substantial to perfect for both HR-OCT (0.88) and standard resolution OCT(0.82). However, HR-OCT showed higher accuracy in identifying iRORA lesions compared to standard OCT. Qualitative assessment of features demonstrated higher agreement for HR-OCT, particularly in identifying ELM (0.95) and EZ disruption (0.94). Quantitative measurements of features such as hypertransmission defects, RPE attenuation/disruption, EZ disruption width, and ELM disruption width showed excellent inter-reader agreement with HR-OCT (> 0.90 for all features) but only moderate agreement with standard OCT (0.51-0.60). ConclusionsThe study results suggest that HR-OCT improves the accuracy and reliability of classifying and quantifying atrophic lesions associated with AMD compared to standard resolution OCT. The quantitative findings in particular may have implications for future research and clinical practice, especially with the availability of therapeutic agents for treating geographic atrophy (GA) and the development of commercially available HR-OCT devices.

Comparative quantifications and morphological monitoring of the topical treatment approach for onychomycosis-affected in vivo toenail using optical coherence tomography: A case study

Onychomycosis is one of the most common toenail fungal infections that affect the quality of life of many patients. Long-term and noninvasive monitoring of morphological changes of onychomycosis-affected nail plate aids the medication process and provides comfort for patients. However, existing medical and dermatological imaging methods have various types of limitations in nail investigation due to low resolution, lack of volumetric data, the necessity of highly trained personnel for image analysis, and the variety of protocols. In this study, qualitative monitoring-based quantitative assessments were performed to assess the morphological changes of onychomycosis-affected toenail for 15 consecutive weeks using high-resolution optical coherence tomography (OCT). Layer intensity and surface roughness measuring algorithms were applied to two-dimensional OCT cross-sectional images to detect gradual changes in the morphological structure of the diseased toenail. A depth intensity profile and the angle formed between the nail plate and nail fold were also used to analyze the thickness and shape of the toenail plates, respectively. The quantitative and morphological monitoring results revealed significant changes in the toenail structure before and during the treatment process, confirming the healing of the diseased toenail. Therefore, the proposed noninvasive optical analysis approach can be applied to monitor nail abnormalities and evaluate the process of diseased toenail medication.