Eyes Of Individuals Research Articles

Incidence of blindness in open-angle glaucoma in Sweden: a long-term follow-up study.

Open-angle glaucoma (OAG) is a leading cause of irreversible blindness. There are no prospective studies on the risk of developing blindness in both eyes in individuals with definite OAG. A total of 354 patients with newly diagnosed OAG, who had participated in four studies conducted at the Eye Department in Tierp, Sweden, from 1979 to 2006, were included in the investigation. Using the World Health Organization's criteria for blindness, medical records, glaucoma case records, and visual fields were reviewed to identify patients who developed bilateral blindness. Incidence proportions and incidence rates were estimated. To assess potential risk factors for blindness, standardised morbidity ratios (SMRs) were calculated. The effects of age and sex were also analysed using Cox proportional hazard models. By the end of the study in August 2023, 33 cases of blindness caused by OAG had been found, corresponding to an incidence proportion of 9.3% (95% confidence interval [CI]: 6.5-12.8%). Within the first 20 years, 29 cases were detected, yielding a proportion of 8.2% (95% CI: 5.5-11.6%). The incidence rate was estimated to be 8.6 per 1,000 person-years (95% CI: 5.9-12.6 per 1,000 person-years). Glaucoma-related blindness was associated with male sex (SMR 2.33; 95% CI: 1.13-4.80). The hazard ratio was doubled for every 5 year of increasing age (2.21; 95% CI: 1.60-3.05). In this study of blindness in newly diagnosed OAG in a Swedish population, approximately one in 10 patients progressed to bilateral blindness caused by the disease. Old age and male sex were identified as significant risk factors.

The effect of ocular dominance on choroidal structures

ABSTRACT This study aimed to compare the dominant and non-dominant eyes of healthy individuals in terms of CT and CVI values to assess the effect of ocular dominance on choroidal morphology. Three hundred eyes of 150 individuals were included in this study. All patients underwent routine ophthalmological examinations and hole-in-the-card tests to determine the dominant eye. EDI-OCT was used to obtain choroidal images. Choroidal thickness (CT) was measured at three points on the choroid including the subfoveal region (subfoveal choroidal thickness (SFCT)), 1500 μm nasal (NCT) and temporal (TCT) to the fovea. Choroidal vascularity index (CVI), total choroidal area (TCA), luminal area (LA), and stromal area (SA) were measured at fovea-centered choroidal area by image binarization via Image J software. While 93(%62) participants were right-eyed, 57(%38) participants were left-eyed. We could not detect any difference in SFCT, NCT, TCT, TCA, LA, SA, and CVI measurements between the dominant and the non-dominant eyes. (p > 0.05 for all). We could not detect any effect of ocular dominance on choroidal structures. These results also support the use of randomized ocular data regardless of which eye is dominant when investigating CVI and CT in scientific research.

Heatmap analysis for artificial intelligence explainability in diabetic retinopathy detection: illuminating the rationale of deep learning decisions.

The opaqueness of artificial intelligence (AI) algorithms decision processes limit their application in healthcare. Our objective was to explore discrepancies in heatmaps originated from slightly different retinal images from the same eyes of individuals with diabetes, to gain insights into the deep learning (DL) decision process. Pairs of retinal images from the same eyes of individuals with diabetes, composed of images obtained before and after pupil dilation, underwent automatic analysis by a convolutional neural network for the presence of diabetic retinopathy (DR), output being a score ranging from 0 to 1. Gradient-based Class Activation Maps (GradCam) allowed visualization of activated areas. Pairs of images with discordant DL scores or outputs within the pair were objectively compared to the concordant pairs, regarding the sum of activations of Class Activation Mapping (CAM), the number of activated areas, and DL score differences. Heatmaps of discordant pairs were also qualitatively assessed. Algorithmic performance for the detection of DR attained 89.8% sensitivity, 96.3% specificity and area under the receiver operating characteristic (ROC) curve of 0.95. Out of 210 comparable pairs of images, 20 eyes and 10 eyes were considered discordant according to DL score difference and regarding DL output, respectively. Comparison of concordant versus discordant groups showed statistically significant differences for all objective variables. Qualitative analysis pointed to subtle differences in image quality within discordant pairs. The successfully established relationship among objective parameters extracted from heatmaps and DL output discrepancies reinforces the role of heatmaps for DL explainability, fostering acceptance of DL systems for clinical use.

Optical coherence tomography angiography findings in patients affected by giant cell arteritis, with and without ocular involvement: a pilot study.

We evaluated the clinical features and retinal and disk perfusion characteristics by using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in a subset of giant cell arteritis (GCA) patients who manifested anterior ischemic optic neuropathy (AION), in a subset of GCA patients without ocular involvement, and in a control group composed of healthy controls. We performed an observational study on the eyes of GCA patients affected by arteritic AION both in acute and chronic phases, unaffected eyes of AION, eyes of GCA patients without ocular involvement, and in a control group of healthy eyes of healthy individuals. All patients underwent a complete ophthalmic examination and an OCT and OCTA of the macula and the disk. The study evaluated 10 eyes of GCA patients with AION (AION group), 8 unaffected eyes of GCA patients with AION in another eye (unaffected eyes of AION group), 16 eyes of GCA patients without ocular involvement (non-ocular group), and 22 eyes of healthy patients (healthy group). The ganglion cell complex (GCC) superior and inferior thicknesses were significantly lower in the AION group compared to the unaffected eyes of the AION group (p = 0.045 and p = 0.034, respectively). All OCTA vascular density parameters of the optic disk analyzed in this study (optic nerve head (ONH) whole, superior, inferior, radial peripapillary capillary plexus (RPCP) whole, superior, inferior, lamina cribrosa (LC) whole, superior, inferior) resulted significantly lower in the AION group compared to the unaffected eyes group (p < 0.05 for all the comparisons). The ONH whole and inferior were statistically higher in the healthy group in comparison to the group of GCA patients without ocular involvement (p = 0.008 and p = 0.006, respectively). The ONH inferior was also statistically higher in the unaffected eyes of the AION group in comparison to the non-ocular group (p = 0.045). Regarding the OCTA macular vessel density parameters, the superficial capillary plexus (SCP), whole and inner, were statistically lower in the AION group compared with the unaffected eyes of the AION group. We found a profound vascular impairment in eyes affected by AION and areas of hypoperfusion in the eyes of patients with GCA without ocular involvement, good BCVA, and no clinically significant features. We hypothesized that these areas of lower vessel density might represent areas of subclinical hypoperfusion that cannot be detected ophthalmoscopically.

Field- and laboratory-based studies on correlates of Chlamydia trachomatis transmission by Musca sorbens: Determinants of fly-eye contact and investigations into fly carriage of elementary bodies.

Musca sorbens (Diptera: Muscidae) flies are thought to be vectors of the blinding eye disease trachoma, carrying the bacterium Chlamydia trachomatis (Ct) between the eyes of individuals. While their role as vectors has been convincingly demonstrated via randomised controlled trials in The Gambia, studies of fly-borne trachoma transmission remain scant and as such our understanding of their ability to transmit Ct remains poor. We examined fly-eye contact and caught eye-seeking flies from 494 individuals (79% aged ≤9 years) in Oromia, Ethiopia. Ct-carrying flies (harbouring Ct DNA) were found to cluster spatially in and nearby to households in which at least one resident had Ct infection. Fly-eye contact was positively associated with the presence of trachoma (disease), lower human body weight and increased human body temperature. Studies of laboratory-reared M. sorbens indicated that Ct is found both externally and internally following feeds on Ct culture, with scanning electron microscopy revealing how Ct bodies can cling to fly hairs (setae). Testing for Ct on field-caught M. sorbens found fly 'bodies' (thorax, wings and abdomen) to consistently test positive for Ct while legs and heads were infrequently Ct-positive. These studies strongly support the role of M. sorbens as vectors of trachoma and highlight the need for improved understanding of fly-borne trachoma transmission dynamics and vector competence.

Racial and Ethnic Differences in the Prevalence and Treatment Patterns for Neovascular Glaucoma in the American Academy of Ophthalmology IRIS® Registry

PurposeTo examine racial and ethnic differences in the prevalence and treatment patterns for neovascular glaucoma (NVG) in at-risk individuals in the American Academy of Ophthalmology (Academy) IRIS® Registry (Intelligent Research in Sight). ParticipantsEyes in the IRIS Registry with a retinal ischemia based on a history of proliferative diabetic retinopathy (PDR), retinal vein occlusion (RVO), and/or ocular ischemic syndrome (OIS). MethodsRace and ethnicity was defined as Asian, Black, Hispanic/Latino, Non-Hispanic White, and Other/Unknown. In eyes with retinal ischemia, the outcome was neovascular glaucoma (NVG). In eyes with NVG, outcomes included treatment of retinal ischemia with pan-retinal photocoagulation (PRP), and surgery to lower intraocular pressure (IOP) with trabeculectomy, tube shunt, and cyclophotocoagulation (CPC). Covariates included age, sex, region of residence, insurance type, smoking status, and systemic and ocular comorbidities. Cox proportional hazards regression was used to examine adjusted associations between race and ethnicity and NVG and each type of NVG treatment. Main Outcome MeasuresIncidence of NVG, PRP, trabeculectomy, tube shunt, CPC, and any IOP-lowering surgery ResultsOf 312,106 eyes with retinal ischemia, there were 5,885 (1.9%) with NVG. Compared to eyes of individuals who identified as Non-Hispanic White, eyes of individuals who were Black and Hispanic/Latino had higher hazards of NVG in adjusted analyses (hazards ratio [HR]=1.28, 95% confidence interval [CI]=1.15, 1.43 for Black; HR=1.32, 95% CI=1.17, 1.47 for Hispanic/Latino). Compared to eyes of individuals who were Non-Hispanic White, there was higher hazards of trabeculectomy in eyes of individuals who were Hispanic/Latino (adjusted HR=1.91, 95% CI=1.08, 3.39) and higher hazards of tube shunt (adjusted HR=1.35, 95% CI=1.07, 1.69) and of any IOP-lowering surgery (adjusted HR=1.29, 95% CI=1.09, 1.53) in eyes of individuals who were Black. There were no statistically significant differences in the hazards of PRP or CPC. ConclusionsEyes of Black and Hispanic/Latino individuals with retinal ischemia in the IRIS Registry had higher likelihood of NVG and of IOP-lowering surgery for NVG. Further study is needed to examine the medical and social factors that preclude optimal management of diabetic eye disease, in order to prevent its blinding complications.

Retinal vascular morphological characteristics in diabetic retinopathy: an artificial intelligence study using a transfer learning system to analyze ultra-wide field images.

To investigate the morphological characteristics of retinal vessels in patients with different severity of diabetic retinopathy (DR) and in patients with or without diabetic macular edema (DME). The 239 eyes of DR patients and 100 eyes of healthy individuals were recruited for the study. The severity of DR patients was graded as mild, moderate and severe non-proliferative diabetic retinopathy (NPDR) according to the international clinical diabetic retinopathy (ICDR) disease severity scale classification, and retinal vascular morphology was quantitatively analyzed in ultra-wide field images using RU-net and transfer learning methods. The presence of DME was determined by optical coherence tomography (OCT), and differences in vascular morphological characteristics were compared between patients with and without DME. Retinal vessel segmentation using RU-net and transfer learning system had an accuracy of 99% and a Dice metric of 0.76. Compared with the healthy group, the DR group had smaller vessel angles (33.68±3.01 vs 37.78±1.60), smaller fractal dimension (Df) values (1.33±0.05 vs 1.41±0.03), less vessel density (1.12±0.44 vs 2.09±0.36) and fewer vascular branches (206.1±88.8 vs 396.5±91.3), all P<0.001. As the severity of DR increased, Df values decreased, P=0.031. No significant difference between the DME and non-DME groups were observed in vascular morphological characteristics. In this study, an artificial intelligence retinal vessel segmentation system is used with 99% accuracy, thus providing with relatively satisfactory performance in the evaluation of quantitative vascular morphology. DR patients have a tendency of vascular occlusion and dropout. The presence of DME does not compromise the integral retinal vascular pattern.

Features Associated with Visible Lamina Cribrosa Pores in Individuals of African Ancestry with Glaucoma: Primary Open-Angle African Ancestry Glaucoma Genetics (POAAGG) Study.

There are scarce data regarding the rate of the occurrence of primary open-angle glaucoma (POAG) and visible lamina cribrosa pores (LCPs) in the eyes of individuals with African ancestry; the potential impact of these features on disease burden remains unknown. We recruited subjects with POAG to the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. Through regression models, we evaluated the association between the presence of LCPs and various phenotypic features. In a multivariable analysis of 1187 glaucomatous eyes, LCPs were found to be more likely to be present in eyes with cup-to-disc ratios (CDR) of ≥0.9 (adjusted risk ratio (aRR) 1.11, 95%CI: 1.04-1.19, p = 0.005), eyes with cylindrical-shaped (aRR 1.22, 95%CI: 1.11-1.33) and bean pot (aRR 1.24, 95%CI: 1.13-1.36) cups versus conical cups (p < 0.0001), moderate cup depth (aRR 1.24, 95%CI: 1.06-1.46) and deep cups (aRR 1.27, 95%CI: 1.07-1.50) compared to shallow cups (p = 0.01), and the nasalization of central retinal vessels (aRR 1.33, 95%CI: 1.23-1.44), p < 0.0001). Eyes with LCPs were more likely to have a higher degree of African ancestry (q0), determined by means of SNP analysis (aRR 0.96, 95%CI: 0.93-0.99, p = 0.005 for per 0.1 increase in q0). Our large cohort of POAG cases of people with African ancestry showed that LCPs may be an important risk factor in identifying severe disease, potentially warranting closer monitoring by physicians.

Changes in foveal avascular zone parameters in individuals with prediabetes compared to normoglycemic controls: a systematic review and meta-analysis.

To investigate changes in foveal avascular zone parameters in individuals with prediabetes compared to normoglycemic controls. PUBMED, Scopus and Cochrane Library were searched for published articles comparing the foveal avascular zone between prediabetic individuals and normoglycemic controls as assessed by optical coherence tomography angiography (OCTA). Standardised Mean Difference (SMD) with 95% confidence interval (CI) was computed for the comparison. A total of seven studies were included in our analysis, 6 provided data for the superficial capillary plexus from 345 eyes of individuals with prediabetes and 347 eyes of controls and 4 provided data on the deep capillary plexus from 285 eyes from individuals with prediabetes and 325 eyes of controls. Foveal avascular zone (FAZ) area in the superficial capillary plexus was enlarged in individuals with prediabetes compared to normoglycemiccontrols (SMD = 0.23, 95% CI = 0.03-0.44, p = 0.03, I2 = 27%, 6 studies). There was no statistically significant change in the deep capillary plexus FAZ area between the two groups (SMD = 1.14, 95% CI = -0.06-2.34, p = 0.06, I2 = 97%, 4 studies). FAZ area in the superficial capillary plexus was larger in individuals diagnosed with prediabetes compared to normoglycemic controls. This finding suggests that prediabetes could induce retinal microvascular changes before the onset of clinical diabetes. More original studies are needed to validate the results of the current meta-analysis.

Measurement of retinal and optic nerve head blood flow in glaucomatous individuals compared to normal individuals: an optical coherence tomography angiography study

Study aim Identifing quantitative differences in retinal and optic nerve head blood flow detected by optical coherence tomography (OCT) angiography in moderately to severely affected glaucoma eyes of primary open angle type versus normal individuals. Patients and methods Comparative noninterventional observational prospective research has been performed on 28 eyes (16 individuals). Participants went through examination and imaging protocols. Data were collected during the period from January 2020 to May 2020. The study population was split into two cohorts: the first cohort included 14 eyes of nine individuals who suffered from glaucoma of open-angle type (moderately to severely affected), and the second cohort included 14 eyes of seven normal sex-matching and age-matching individuals. Results We documented a reduction in the vessel density of both the optic nerve head area (P&lt;0.001) and superficial retinal areas in glaucomatous eyes (P&lt;0.001), and this reduction shows statistical significance. Conclusion Quantitative OCT angiography analysis proved affection of both peripapillary and macular vessel density in glaucoma of open-angle type, signifying the OCT angiography role in understanding the disease’s underlying etiology.

Brainwaves and Emotional Responses to Changes in Red Eye Shadow Brightness and Saturation

Purpose: Investigating how Munsell’s primary color (i.e., red eye shadow) influences human brain and emotional responses to establish foundational data for image formation. Methods: We analyzed the relative power differences in background brainwaves due to variations in five levels of brightness and saturation for each eye both in male and female individuals in their twenties. We used the coefficient of variation for brainwaves for our analysis. In addition, we assessed the preferences for altered red eye shadow and the emotional responses to determine the average preference index. We performed statistical analysis for brainwaves and emotional evaluations using repeated measure analysis of variance in SPSS, followed by post hoc testing with Tukey’s test at a 95% confidence level. Results: The brainwave and emotional responses obtained by presenting red eye shadow brightness and saturation modification-created stimuli revealed that both men and women exhibited beta and gamma wave activation and alpha wave inactivation upon low brightness and high saturation stimuli. Men were more sensitive to brightness stimuli, whereas women displayed higher-level variability in brainwave responses upon saturation changes. Both genders preferred red eye shadows with brightness and saturation levels of 8 and 2, respectively. The perceptual image responses indicated that stimuli with low or high brightness were perceived as modern and subtle or clear and cute, respectively. Medium or high saturation stimuli were perceived as clear and natural or associated with a modern image, respectively, by both genders. Conclusion: This study demonstrated the impact of various color stimuli on the human brain and emotions. We consider the obtained results as foundational data, which could be used in future image consulting or when crafting desired image presentations.

Defining reference values of arterioles in healthy individuals for studies with adaptive optics imaging.

To investigate age-dependent wall to lumen ratio (WLR) reference values for healthy individuals in adaptive optics imaging (AO). WLR serves as an objective, dimensionless parameter for the evaluation of structural changes in vessels caused by conditions like arterial hypertension, diabetes or vascular stenosis. 50 right eyes of healthy individuals were examined by adaptive optics imaging. The central big arterioles and smaller arterial branches at least one disc diameter away from the optic disc, approximately above or below the macula were measured by the manufacturer's software. The wall-lumen-ratio (WLR), the wall cross-sectional area (WCSA) and lumen diameter (LD) were assessed. Subsequent data analysis was performed with a focus on variables including age, gender and blood pressure. Normative values for WLR, WCSA and LD in 5 different age groups could be established. However, no significant differences between the age groups were found. Intra-subject comparisons revealed significantly higher WLRs on peripheral branches when compared to central arterioles. WLR showed in this normotensive cohort no relevant correlation with the systolic, diastolic and mean blood pressure. Gender and intraocular pressure had no influence on the vascular parameters. AO is capable of examining vascular alterations in arterioles at an almost microscopic level. Age did not seem to alter WLR, normotensive blood pressure parameters showed also no significant impact. AO-based vessel analysis may provide clinically useful biomarkers for cardiovascular health and should be tested in future studies.

The impact of suboccipital muscle inhibition on postural stability in young individuals

Introduction. Postural stability is the result of cooperation between the musculoskeletal and nervous systems. The stability of standing posture ensures the spatial arrangement of the body, where the center of gravity falls within the center of the support base. FHT (Forward Head Posture) increases the extension in the occipito-cervical joint and upper cervical spine, deepening the flexion of the lower cervical segment, causing improper contraction of the suboccipital muscles. Disorders in the tone of the suboccipital muscles may affect the balance. Objective. The research hypothesis was made that a single 4-minute suboccipital muscle inhibition procedure influences the change in postural stability values with open and closed eyes in individuals with cranio vertebral angle (CVA) within the normal range and below. Materials and Methods. Healthy participants (10 women and 8 men) with an age of 22.7 ± 0.58. The participants took part in the study. They were classified into research groups based on the CVA angle assessment. Postural stability analysis used the Koordynacja stabilometric platform. Measurements were taken with open and closed eyes, before and immediately after suboccipital muscle inhibition. Results. The suboccipital muscle inhibition was observed to affect anterior-posterior (A-P) displacements in group A (CVA &lt; 50) p-value = 0.0168, with no significant impact in group B (CVA ≥ 50), p-value = 0.3695. Conclusion. A single 4-minute suboccipital muscle inhibition procedure does not significantly influence postural stability parameters in the examined groups, except for A-P displacements with open eyes in the CVA &lt; 50 group.

Associations between unilateral amblyopia in childhood and cardiometabolic disorders in adult life: a cross-sectional and longitudinal analysis of the UK Biobank

Amblyopia is a common neurodevelopmental condition and leading cause of childhood visual impairment. Given the known association between neurodevelopmental impairment and cardiometabolic dysfunction in later life, we investigated whether children with amblyopia have increased risk of cardiometabolic disorders in adult life. This was a cross-sectional and longitudinal analysis of 126,399 United Kingdom Biobank cohort participants who underwent ocular examination. A subset of 67,321 of these received retinal imaging. Data analysis was conducted between November 1st 2021 and October 15th 2022. Our primary objective was to investigate the association between amblyopia and a number of components of metabolic syndrome and individual cardiometabolic diseases. Childhood amblyopia, dichotomised as resolved or persisting by adulthood, cardiometabolic disease and mortality were defined using ophthalmic assessment, self-reported, hospital admissions and death records. Morphological features of the optic nerve and retinal vasculature and sublayers were extracted from retinal photography and optical coherence tomography. Associations between amblyopia and cardiometabolic disorders as well as retinal markers were investigated in multivariable-adjusted regression models. Individuals with persisting amblyopia (n=2647) were more likely to be obese (adjusted odds ratio (95% confidence interval): 1.16 (1.05; 1.28)), hypertensive (1.25 (1.13; 1.38)) and diabetic (1.29 (1.04; 1.59)) than individuals without amblyopia (controls, (n=18,481)). Amblyopia was also associated with an increased risk of myocardial infarction (adjusted hazard ratio: 1.38 (1.11; 1.72)) and death (1.36 (1.15; 1.60)). On retinal imaging, amblyopic eyes had significantly increased venular caliber (0.29 units (0.21; 0.36)), increased tortuosity (0.11 units (0.03; 0.19)), but lower fractal dimension (-0.23 units (-0.30;-0.16)) and thinner ganglion cell-inner plexiform layer (mGC-IPL,-2.85 microns (-3.47;-2.22)). Unaffected fellow eyes of individuals with amblyopia also had significantly lower retinal fractal dimension (-0.08 units (-0.15;-0.01)) and thinner mGC-IPL (-1.14 microns (-1.74;-0.54)). Amblyopic eyes with a persisting visual deficit had smaller optic nerve disc height (-0.17 units (-0.25;-0.08)) and width (-0.13 units (-0.21;-0.04)) compared to control eyes. Although further research is needed to understand the basis of the observed associations, healthcare professionals should be cognisant of greater cardiometabolic dysfunction in adults who had childhood amblyopia. Differences in retinal features in both the amblyopic eye and the unaffected non-amblyopic suggest generalised versus local processes. Medical Research Council (MR/T000953/1) and the National Institute for Health and Care Research.

Depressive symptoms and visual attention to others’ eyes in healthy individuals

BackgroundEye contact is a fundamental part of social interaction. In clinical studies, it has been observed that patients suffering from depression make less eye contact during interviews than healthy individuals, which could be a factor contributing to their social functioning impairments. Similarly, results from mood induction studies with healthy persons indicate that attention to the eyes diminishes as a function of sad mood. The present screen-based eye-tracking study examined whether depressive symptoms in healthy individuals are associated with reduced visual attention to other persons’ direct gaze during free viewing.MethodsGaze behavior of 44 individuals with depressive symptoms and 49 individuals with no depressive symptoms was analyzed in a free viewing task. Grouping was based on the Beck Depression Inventory using the cut-off proposed by Hautzinger et al. (2006). Participants saw pairs of faces with direct gaze showing emotional or neutral expressions. One-half of the face pairs was shown without face masks, whereas the other half was presented with face masks. Participants’ dwell times and first fixation durations were analyzed.ResultsIn case of unmasked facial expressions, participants with depressive symptoms looked shorter at the eyes compared to individuals without symptoms across all expression conditions. No group difference in first fixation duration on the eyes of masked and unmasked faces was observed. Individuals with depressive symptoms dwelled longer on the mouth region of unmasked faces. For masked faces, no significant group differences in dwell time on the eyes were found. Moreover, when specifically examining dwell time on the eyes of faces with an emotional expression there were also no significant differences between groups. Overall, participants gazed significantly longer at the eyes in masked compared to unmasked faces.ConclusionsFor faces without mask, our results suggest that depressiveness in healthy individuals goes along with less visual attention to other persons’ eyes but not with less visual attention to others’ faces. When factors come into play that generally amplify the attention directed to the eyes such as face masks or emotions then no relationship between depressiveness and visual attention to the eyes can be established.

Diurnal variation of corneal epithelium and stroma measured by optical coherence tomography

Abstract Purpose: The purpose of the study is to evaluate whether there is a significant diurnal variation in the thickness of corneal epithelium and stroma, in healthy volunteers, using corneal optical coherence tomography (OCT). Introduction: During sleep, closing the eyelids impairs the diffusion of oxygen through the corneal epithelium, resulting in the production of lactic acid, which can interfere with corneal thickness in the 1st min of wakefulness. OCT is an objective and noninvasive accurate method for evaluating corneal epithelium and storm thickness. Methods: A prospective and analytical study investigated the thickness and regularity of the cornea and its epithelium in the eyes (n = 30) of individuals without comorbidities. The volunteers underwent corneal OCT examination in two different periods: between 30 and 60 min after waking up and in the late afternoon of the same day. The study was carried out at Médicos de Olhos S.A, Curitiba, Brazil, between August and October 2023. For statistical analysis, the T-Student test was used, considering P &lt; 0.0001 as statistically significant. Results: Epithelium variability index, in OD (P = 0.965) and in OS (P = 0.516), did not present a statistically significant difference. The difference in thickness between epithelium minimum and maximum, OD (P = 0.880) and OS (P = 1.0), also did not show a statistically significant difference. Discussion: It was possible to verify that the epithelial and stromal thickness of the cornea did not show significant diurnal variations. Furthermore, the regularity of epithelial thickness remained constant, as indicated by the epithelial variability index value.

Longitudinal changes in the ganglion cell complex thickness in acute central serous chorioretinopathy using spectral-domain optical coherence tomography

In this retrospective longitudinal cohort study, we investigated the temporal changes in the peripapillary retinal nerve fiber layer (pRNFL) and inner retinal thickness in patients with acute central serous chorioretinopathy (CSC) using spectral-domain optical coherence tomography (SD-OCT). We followed up with these patients for 6 months, and during this period, the thickness of the pRNFL and the ganglion cell complex (GCC) in CSC patients were compared with the eyes of normal healthy individuals. The study also examined the correlation between the pRNFL thickness, GCC thickness, and visual acuity. The research sample consisted of 67 patients (43 male and 24 female) with an average age of 49.72 ± 9.87 years. The initial findings showed no significant differences in the pRNFL and GCC thickness between the study and fellow eye, study and normal healthy eyes, and fellow and normal healthy eyes. There was no significant difference in the pRNFL and GCC thickness when comparing the study eye with the fellow eye for 6 months. In the study eye, no significant difference was observed when comparing the initial GCC and pRNFL thickness with those at 1, 3, and 6 months. Visual acuity improved significantly from 0.18 ± 0.23 logMAR to 0.04 ± 0.06 logMAR (p < 0.001). The GCC and pRNFL thickness did not significantly affect visual acuity. In conclusion, acute CSC patients did not show significant changes in the pRNFL and inner retinal thickness, suggesting that the GCC and pRNFL do not substantially influence the short-term visual prognosis in these patients.

Longitudinal changes in peri-papillary retinal nerve fiber layer thickness in patients with unilateral branch retinal vein occlusion.

Associations between retinal venous occlusion (RVO), elevated intraocular pressure, and glaucoma have been reported. Further investigations into structural alterations in the fellow eyes of individuals with unilateral RVO have revealed that the peripapillary retinal nerve fiber layer is thinner than in healthy eyes, suggesting that there may be systemic risk factors common to both RVO and glaucoma. We aimed to evaluate changes in peripapillary retinal nerve fiber layer thickness (pRNFLT) among individuals with unilateral branch retinal vein occlusion (BRVO). This prospective observational study recruited 30 individuals (60 eyes) with newly diagnosed unilateral BRVO and macular edema, and a control group of 30 healthy individuals (30 eyes) with no abnormalities on fundus examination or concurrent systemic comorbidities. After baseline measurements, the participants were reassessed at 6, 12, and 24 months by measuring global and sectoral pRNFLT using spectral-domain optical coherence tomography. The mean age and sex distributions were comparable between the patient and control groups (both P > 0.05). When compared to fellow eyes, global and sectoral pRNFLT in eyes with BRVO were significantly higher at baseline (all P < 0.05). Over time, pRNFLT decreased dramatically, and by the conclusion of the two-year follow-up, there was a significant reduction from baseline in the affected eyes (all P < 0.05). Likewise, affected eyes experienced a significant improvement in best-corrected distance visual acuity and central macular thickness over the two-year follow-up (both P ≤ 0.001). Comparing the global and all-sector pRNFLT of fellow eyes in the patient group with those of normal eyes in the control group, there were no significant differences at any visit, except in the temporal sector, which revealed a significant reduction in pRNFLT at 24 months in the fellow eyes of patients with unilateral BRVO (P = 0.02). Patients with unilateral BRVO experienced a significant reduction in pRNFLT in the affected eyes and, to a lesser extent, in the fellow eyes, compared with that of the control arm, suggesting that they are prone to retinal nerve fiber layer damage. The reduction in pRNFLT in the normal fellow eyes of patients with BRVO may be attributed to age or concurrent systemic comorbidities. Further studies with long follow-up periods are required to shed light on the etiology of functional and structural changes in both the retinal nerve fiber layer and ganglion cell complex in the normal and affected eyes of patients with unilateral BRVO.

The Assessment of Radial Peripapillary Capillary Vessel Density in Adult Children of Patients With Primary Open Angle Glaucoma.

The observed decrease in radial peripapillary capillary vessel density among adult children of individuals with primary open angle glaucoma, in comparison to controls, suggests the possibility of early microvascular alterations in the eyes of these at-risk individuals. To compare the radial peripapillary capillary vessel density (RPCVD) and peripapillary retinal nerve fiber layer (RNFL) thickness values of eyes between healthy adults with a maternal or paternal history of primary open angle glaucoma (POAG) and age-matched healthy controls without a family history of POAG. RPCVD values and RNFL thicknesses in the peripapillary region and 4 quadrants (superior, inferior, nasal, and temporal) were evaluated using optical coherence tomography angiography among 30 adult children of patients with POAG and 30 age-matched healthy controls without a family history of POAG. The mean whole image RPCVD (51.6±1.7% vs. 49.8±1.7%, P =0.0006) and average RPCVD (54.7±1.7% vs. 53.2±2.1%, P =0.006) values were significantly lower in the adult children of patients with POAG compared with age-matched healthy controls without a family history of POAG. There was no difference in terms of RNFL thickness values in any region. Despite having similar RNFL thickness values to the control group, the observation of lower RPCVD in the eyes of adult children of POAG patients may indicate potential early vascular alterations. The result of the present study encourages further longitudinal studies to determine the potential importance of the underlying vascular alterations in these high-risk individuals.

A new approach to measure interocular suppression in amblyopia and strabismus

Interocular suppression is commonly estimated by the contrast “balance point” between the eyes in individuals with amblyopia, in which the depth of suppression is defined as the increased contrast in the amblyopic eye that is perceptually matched to the fellow eye. However, this method may not be suitable for individuals with strabismus who have normal or even better contrast sensitivity in the non-fixating eye. In this study, I introduced a new approach that can be used for measuring interocular suppression for both amblyopia and strabismus without balancing contrasts between the eyes. The method consists of the following components:•The stimuli have equal contrasts in both eyes.•The percepts of objects seen monocularly and binocularly are compared.•Interocular suppression is defined as the percept of object in the amblyopic eye is suppressed when an object is presented in the fellow eye.