Ocular Measurements Research Articles

Retrospective Comparison of the Myopia Master and the Lenstar LS900 Axial Length Measurements in Children with Myopia.

This study is a retrospective analysis to compare ocular biometry measurements of axial length in children with myopia using Myopia Master (OCULUS, Wetzlar, Germany) and Lenstar LS900 (HAAG-STREIT AG, Köniz, Switzerland). Axial length measurements obtained with both instruments within a 3-week period were collected retrospectively. Measurements were visualized with a Bland-Altman plot. For statistical evaluation, a paired t-test was applied, and the Pearson correlation coefficient (r) was established. Sixty-one eyes from 31 myopic patients (59% male, 41% female) with a mean age of 11.34 ± 3.25 years (range: 6 - 18 years) were identified. Mean axial length was 24.7 mm (SD 1.29) with the Myopia Master and 24.69 mm (SD 1.30) with the Lenstar LS900 (Pearson correlation: r = 0.9991). The average difference of the axial length measurement between the two biometers was 0.00 064 mm ± 0.056 SD (p = 0.9293). The axial length measured by Myopia Master and Lenstar LS900 did not differ significantly. Thus, previous values obtained with the Lenstar LS900 can be applied to assess myopia progression.

Longitudinal choroidal thickness changes among Chinese young adults with various refractive errors.

To determine the characteristics of longitudinal choroidal thickness (CT) and axial length (AL) changes in a group of Chinese young adults with various refractive errors. In this 2 year prospective cohort study, a total of 291 (314 enrolled at baseline) Chinese medical freshmen aged 18 to 22 years (mean age, 18.7 ± 0.9 years) underwent eye examinations at baseline and follow-up visits, including cycloplegic refraction, ocular biometry measurements, and swept-source optical coherence tomography. Choroidal thickness measurements were performed at nine locations in the macular area. At baseline, the CT and AL was significant differences among groups of emmetropia, mild to moderate myopia and high myopia. During a two-year period, there were significant differences found in the changes of the subfoveal CT (p < 0.001) and parafoveal CT of 7 locations between emmetropia and mild to moderate myopia, and the changes of the subfoveal CT (p = 0.002) and parafoveal CT of 6 locations between emmetropia and high myopia. But there were no differences for AL and SE (p > 0.05). The multivariable linear regression analysis showed that baseline subfoveal CT (per 1 μm) was a significant factor affecting the changes of subfoveal CT (p < 0.001), whereas age, gender, and baseline AL were not significantly associated. The longitudinal change in CT varies with refractive errors in Chinese young adults aged 18 to 22 years over a two-year period. The changes of subfoveal CT were significantly associated with the baseline subfoveal CT, but not associated with baseline AL.

Normal periocular anthropometric measurements in an Australian population

PurposeTo report the normative ocular and periocular anthropometric measurements in an Australian cohort and investigate how these may be affected age, gender, and ethnicity.MethodsProspective study of patients presenting to the Royal Adelaide Hospital. Patient with orbital or eyelid disease, previous surgery, craniofacial abnormalities, pupil abnormalities, strabismus, and poor image quality was excluded. Standardised photographs were taken in a well-illuminated room. A green dot with a diameter of 24 mm was placed on the participant’s foreheads for calibration between pixels and millimetres. Ocular and periocular landmarks were segmented to calculate the periorbital measurements. Independent sample t test was used to compare male and female subjects, Pearson’s correlation was used to correlate periocular dimensions with age, and ANOVA with Bonferroni was used to compare periocular dimension between ethnic groups.ResultsSeven hundred and sixty eyes from 380 participants (215 female, mean age 58 ± 18 years) were included. The mean marginal reflex distance (MRD) 1 was 3.5 mm and decreased with increasing age (r = − 0.09, p = 0.01) and MRD 2 was 5.2 mm. Compared to Caucasians, African subjects had a significantly larger interpupillary distance and outer intercanthal distance, whereas East Asians had a significantly larger inner intercanthal distance (p < 0.05). The values of marginal reflex distance 2, palpebral fissure height, horizontal palpebral aperture, inner intercanthal distance, interpupillary distance and outer intercanthal distance were significantly higher in male subjects than female subjects (p < 0.05).ConclusionsNormative periocular dimensions may vary according to age, gender, and ethnicity. An understanding of normal periocular dimensions is important in the evaluation of orbital disease across different ethnic groups and may serve as reference points for oculoplastic surgery and industry.

Non-Coding RNA Investigations in Cutaneous Melanoma: A Step forward in Discovering Novel Biomarkers

Non-Coding RNA Investigations in Cutaneous Melanoma: A Step forward in Discovering Novel Biomarkers

Myopia risk behaviour related to the COVID-19 lockdown in Europe: The generation R study.

To battle the spreading of the COVID-19 virus, nationwide lockdowns were implemented during 2020 and 2021. Reports from China revealed that their strict home confinements led to an increase in myopia incidence. The Netherlands implemented a more lenient lockdown, which allowed children to go outside. We evaluated the association between COVID-19 restrictions, myopia risk behaviour and myopia progression in Dutch teenagers. A total of 1101 participants (mean age 16.3± 3.65 yrs) completed questionnaires about their activities before, during and after lockdown (March-October 2020). We used a repeated-measures ANOVA to compare time use between these time periods. Ocular measurements were acquired before the COVID-19 pandemic when participants were 13 years old; only 242 participants had ocular measurements at 18 years of age at the time of this analysis. Linear regression analyses were used to evaluate the association between lifestyle factors and myopia progression. Children were on average 16.2 (1.03) years of age during lockdown. Total nearwork increased from 8.11 h/day to 11.79 h/day, and remained higher after lockdown at 9.46 h/day (p< 0.001). Non-educational nearwork increased by 2.22 h/day (+49%) during lockdown and was associated with faster axial length progression (B 0.002 mm/h/year; SE 0.001 p= 0.03). Before and during lockdown, the mean time spent outdoors was similar (1.78 h/day and 1.80 h/day, respectively). After lockdown, time spent outdoors decreased to 1.56 h/day (p< 0.001). The Dutch lockdown significantly increased digitised nearwork in adolescents but did not affect outdoor exposure. The changes in time spent performing nearwork remained after the lockdown measures had ended. We expect that the COVID-19 pandemic may lead to an increase in myopia prevalence and progression in European children.

Key Factors in Early Diagnosis of Myopia Progression within Ocular Biometric Parameters by Scheimpflug Technology

The aim of this study was to evaluate the relationship between myopia and ocular biometric variables using the Pentacam AXL® single rotation Scheimpflug camera. This prospective, cross-sectional, single-center study was performed in fifty Caucasian patients aged between 18 and 30 years (24.84 ± 3.04 years). The measured variables included maximum and minimum keratometry (K1 and K2, respectively), anterior chamber depth (ACD), corneal horizontal diameter or white to white (WTW), central corneal thickness (CCT), corneal asphericity (Q), and axial length (AXL). The tomographic and biometric measurements were considered optimal when the quality factor was greater than 95% according to the manufacturer's software instructions. The AXL presented a significant correlation with the spherical equivalent without cycloplegia (SE without CP), age at onset of myopia (r = -0.365, p = 0.012), mean keratometry (Km) (r = -0.339, p = 0.016), ACD (r = 0.304, p = 0.032), and WTW (r = 0.406, p = 0.005). The eyes with AXL higher than 25 mm had earlier onset; higher SE without CP, AXL, and Q; and a flatter Km. AXL is the biometric variable with the greatest influence on the final refractive state in the adult myopic eye. Ophthalmologists and optometric management must consider these biometric differences in order to identify the most appropriate correction techniques in each case. The use of the Pentacam AXL in ocular biometric measurement is effective, reproducible, and non-invasive.

Near work, light levels and dioptric profile - Which factor dominates and influences the short-term changes in axial length?

Given the agonistic nature of near work to promote axial elongation and the antagonistic nature of time outdoors to prevent myopia, we aimed to investigate the following: (a) how the short-term effect of near work performed outdoors (Experiment 1) influences axial length and (b) how near work performed in two different dioptric profiles (uncluttered and cluttered) alters the changes in central axial length (Experiment 2). Forty-six adults (age range: 19-32 years) participated in the study. In Experiment 1, 22 participants completed a 15-min distance task and a reading task in both the outdoor (~30,000 lux) and indoor (~70 lux) locations. In Experiment 2, 24participants performed the same reading task at a study desk in uncluttered and cluttered reading environments. Pre- and post-task ocular biometry measurements were performed for each session using a non-contact biometer. In Experiment 1, a significant increase in axial length from baseline was found after performing reading tasks in both outdoor (mean ± SEM: +12.3± 3.4μm, p= 0.001) and indoor locations (+11.9± 3.1μm, p= 0.001). In Experiment 2, axial length increased significantly from baseline to post reading task, in both uncluttered (+17.9± 3.5μm, p< 0.001) and cluttered reading environments (+19.2± 2.9μm, p< 0.001). No significant changes in axial length were observed either between outdoor and indoor locations (p= 0.92) or between the uncluttered and cluttered reading environment (p= 0.75). Independent of light intensity (outdoor or indoor location) and dioptric profile of the near-work environment (uncluttered or cluttered), a 15-min reading task led to a significant increase in axial length. While the long-term effects of these findings need to be evaluated, practitioners should emphasise how near work can reduce the beneficial effects of time outdoors, while providing recommendations related to time outdoors for myopia control.

Comparison of ocular morphological measurement by wide-angle echography and magnetic resonance imaging.

To compare the eye axial length (AL), equatorial horizontal diameter (HD), and equatorial vertical diameter (VD) of normal eyes using a novel wide-angle, arc-scanning, ultrasound diagnostic device for wide-angle B-mode echography. In this cross-sectional study, wide-angle B-mode echography and magnetic resonance imaging (MRI) were conducted on 22 normal eyes; the AL, HD, and VD were measured. The mean ALs were as follows: wide-angle B-mode echography, 25.22±1.47mm and MRI, 25.24±1.46mm; a significant correlation was observed between the two measurements (β=0.995 [0.976, 1.013]; p<0.001; 95% R2=1.00). The mean HDs were as follows: wide-angle B-mode echography, 22.33±0.84mm and MRI, 22.55±0.90mm; a significant correlation was observed between the two measurements (β=0.902 [0.750, 1.179]; p<0.001; 95% R2=0.81). The mean VDs were as follows: wide-angle B-mode echography, 22.77±0.91mm; and MRI, 22.88±0.92mm; a significant correlation was observed between the two measurements (β=0.966 [0.853, 1.097]; p<0.001; 95% R2=0.93). There were no significant differences in the measurements for each parameter by wide-angle B-mode echography and MRI. Therefore, wide-angle B-mode echography permits accurate visualization of ocular morphology.

A STUDY ON RETINITIS PIGMENTOSA AS A CAUSE OF BLINDNESS IN PATIENTS ATTENDING REGIONAL EYE HOSPITAL, KURNOOL FOR BLIND CERTIFICATE

Aim: To study Retinitis Pigmentosa as a cause of blindness in patients attending Regional Eye Hospital, Kurnool for blind certificate. Methods: A total of 1020 patients of all age groups attending to Regional Eye Hospital, Kurnool for blind certificate during the period August 2020 to August 2022 were included and examined which include visual acuity testing using Snellen chart, refraction, slit lamp biomicroscopy,intra ocular pressure measurement using Goldmann Applanation Tonometer,fundus examinationwith indirect ophthalmoscope, visual field testing using Humphrey field analyser. Fundus picture was taken using Zeiss fundus camera. Patients having retinal pathology were exclusively included in the study and others were excluded. Results: Out of 1020 patients, 40 patients had Retinitis Pigmentosa with involvement of both eyes. Of these 40 patients, 23 were males and 17 were females indicating that males were more commonly affected than females. 6 patients had 100% disability, 10 patients had 75% disability, 24 patients had 40% disability. Conclusion: Retinitis Pigmentosa is one among the non-treatable cause of blindness which results due to consanguineous marriages as it is an inherited eye disease.

Relationship between clinical parameters and quality of life in primary Sjögren’s Syndrome: a prospective study

ObjectivesTo quantify the impact of dry eye disease (DED) on health and vision related quality of life (HR-QOL, VR-QOL) in patients with Primary Sjögren’s Syndrome (pSS).MethodsThirty-four participants with a confirmed diagnosis of pSS as per the 2016 ACR EULAR criteria participated. Main outcome measures included ocular surface parameters and HR-QOL and VR-QOL questionnaires. Clinical examination included visual acuity, Schirmer I testing, ocular surface staining (OSS) and measurement of tear film breakup time. The questionnaires included Ocular Surface Disease Index, National Eye Institute Visual Function Questionnaire-25, Short Form-36 (SF-36) and EULAR Sjogren’s Syndrome Patient Reported Index.ResultsDespite the majority of participants (28 female, 6 male, mean age 61.3 years) having attained LogMAR 0.3 or better visual acuity, participants scored low on VR-QOL measures, representing DED related fluctuation in functional vision. All participants suffered from moderate to severe DED. OSS did not correlate with DED symptoms or QOL parameters. Lubricant usage and symptom severity had a statistically moderate to strong negative correlation with VR-QOL and HR-QOL. This was most evident in relation to physical and physiological wellbeing. Compared with normative data, participants had a lower HR-QOL in all scales of the SF-36 ((MD = 9.91 ± 5.16); t(7) = 5.43, p = 0.001).ConclusionsParticipants with pSS have a lower perceived QOL especially in relation to physical and mental wellbeing, correlating to severity of DED symptoms and treatment burden. Clinical signs do not align with symptoms. Therefore, clinicians should remain cognisant, adjusting treatment in accordance with patient reported perceptions.

Ultrasound measurement of optic nerve sheath diameter in a healthy adult Colombian population

BackgroundMeasurement of the optic nerve sheath diameter (ONSD) provides a rapid, safe, and easy method for detecting increased intracranial pressure (ICP). However, the normal mean and upper limit values may vary according to sex, age, ethnicity, and ultrasound technique.AimWe aimed to obtain the mean ONSD in a healthy Colombian adult population and to correlate it with demographic and anthropometric measures.MethodsIn a prospective study using a 10–13 MHz linear ultrasound probe, eye transverse diameter (ETD) and ONSD in the transverse (ONSD-TP) and sagittal planes (ONSD-SP) were measured in healthy adult volunteers in Bogota, Colombia.ResultsA total of 100 healthy subjects were included, with a mean age of 26,7 ± 8,3 years and 62 women. The mean ETD, ONSD-TP and ONSD-SP was 23.11 mm (95% confidence interval (CI): 22.90 mm-23.32 mm), 3.96 mm (95% CI: 3.85 mm-4.07 mm) and 4.0 mm (95% CI: 3.90 mm-4.11 mm), respectively. The ONSD in both planes ranged from 2.35 mm to 5.20 mm. There was a significant correlation between ONSD-SP and ONSD-TP (p < 0.0001) but no correlation between the ocular measures and demographic or anthropometric variables (p > 0.05). The intraclass correlation between the eyes was statistically significant.ConclusionOur study shows that ultrasound-measured ONSD in healthy adults in Colombia is similar to that found worldwide. An ONSD of 5.5 mm may be considered the upper limit for healthy adults in Colombia. ONSD can be measured in either plane; there is a good correlation between the two eyes; and ONSD is not modified by demographic or anthropometric characteristics.

Device Development for Ocular Surface Temperature and Heat Flux Density Measurement

Purpose Currently, much attention is paid to measuring the temperature of the ocular surface in various ophthalmic diseases. However, for a comprehensive assessment of heat transfer of the eye, it is advisable to measure both the ocular surface temperature and the heat flux (HF) density. This will expand our knowledge of the physiology of the eye and create new possibilities for diagnosing ocular pathology. The present study aimed to develop a thermoelectric device to study rabbits’ ocular surface temperature and HF density. Methods The multichannel thermoelectric device was developed to measure the ocular surface temperature and HF density. This study included ten rabbits (20 eyes). In all animals, the temperature and the HF density were measured on the surface of the central cornea of both eyes. The measurement was repeated after pupils’ dilation. Results The corneal surface temperature of rabbits was 33.1 ± 0.8 °C, and the HF density of the surface of the cornea was 8.3 ± 0.6 mW/cm2. Our results revealed a high degree of interocular symmetry in the surface HF density in healthy rabbits. After pupil dilation, an increase in the HF density on the surface of the rabbit cornea compared with the initial data and control eye was noted. Conclusions The application of the developed device showed that it is safe and allows for the measurement of the ocular surface temperature and the HF density. We believe that further studies on the ocular surface HF density measurement in various eye diseases will allow us to evaluate the possibilities of this device and technique for diagnostic purposes.

An updated profile of the bovine acute phase response following an intravenous lipopolysaccharide challenge.

The objective was to provide an updated profile of the bovine acute-phase response to include recent advancements in technologies and expanded hematological, cytokine, and serum chemistry variables. Beef steers (n = 32; body weight [BW] = 251 ± 19.5 kg) were fitted with indwelling jugular catheters 1 d before lipopolysaccharide (LPS; 0.25 µg LPS/kg BW from Escherichia coli O111:B4) administration to facilitate serial blood collection. Rectal temperature was measured using indwelling probes, and ocular temperature was measured using infrared thermal imaging. Blood samples were collected for subsequent analysis of serum chemistry, hematology, and cytokine concentrations. Pearson correlation of rectal temperature and ocular infrared temperature was 0.61 (P < 0.01) and the Spearman correlation coefficient was 0.56 (P < 0.01). Interactions of hour × method were observed for ocular and rectal measurements of body temperature in response to endotoxin exposure. Maximum observed temperature was 39.6 °C at 2.5 h for both rectal and ocular measurements. Body temperature differed by method at hours 0.5, 2.5, 4.5, 7.5, 12.5, 36.5, and 47.5 (P < 0.01), but were not different otherwise. All variables of serum chemistry and complete blood count were influenced by LPS administration, except creatinine, serum glucose, and percent basophils (P ≤ 0.02). Alanine aminotransferase and alkaline phosphatase peaked at hour 2 relative to LPS administration, returned to baseline at hour 12 and continued to decrease below the baseline value at hour 48 (P < 0.01). Total protein concentration decreased 3% in response to LPS (P = 0.01). Total white blood cell count decreased 75% after LPS administration at hour 1 (P < 0.01). Lymphocyte count recovered to baseline at hour 6; sooner than neutrophil count at hour 36. Serum cortisol concentration increased 294% relative to baseline at hour 1 followed by a sustained decrease and return to normal concentration at hour 4 (P < 0.01). Additionally, circulating cytokine concentrations changed with time in response to the LPS challenge, excluding aFGF, bFGF, IGF-1, IL-2, IL-4, MCP-1, and ANG-1 (P ≤ 0.08). Maximum observed concentration of TNF-α at hour 1 was 117% greater than the pre-challenge value (P < 0.01). Data presented herein add to existing works to understand the endocrine and immune responses of beef steers administered exogenous LPS, and incorporate recent technologies, additional biomarkers, and an expanded cytokine profile that can be used as referential data in future research.

Comprehensive comparisons of ocular biometry: A network-based big data analysis

PurposeTo systematically compare and rank ocular measurements with optical and ultrasound biometers based on big data.MethodsPubMed, Embase, the Cochrane Library and the US trial registry (www.ClinicalTrial.gov) were used to systematically search trials published up to October 22nd, 2020. We included comparative studies reporting the following parameters measured by at least two devices: axial length (AL), flattest meridian keratometry (Kf), steepest meridian keratometry (Ks), mean keratometry (Km), astigmatism (AST), astigmatism vectors J0 and J45, anterior chamber depth (ACD), aqueous depth (AQD), central corneal thickness (CCT), corneal diameter (CD) and lens thickness (LT). A network-based big data analysis was conducted using STATA version 13.1.ResultsAcross 129 studies involving 17,181 eyes, 12 optical biometers and two ultrasound biometers (with both contact and immersion techniques) were identified. A network meta-analysis for AL and ACD measurements found that statistically significant differences existed when contact ultrasound biometry was compared with the optical biometers. There were no statistically significant differences among the four swept-source optical coherence tomography (SS-OCT) based devices (IOLMaster 700, OA-2000, Argos and ANTERION). As for Ks, Km and CD, statistically significant differences were found when the Pentacam AXL was compared with the IOLMaster and IOLMaster 500. There were statistically significant differences for CCT when the OA-2000 was compared to Pentacam AXL, IOLMaster 700, Lenstar, AL-Scan and Galilei G6.ConclusionFor AL and ACD, contact ultrasound biometry obtains the lower values compared with optical biometers. The Pentacam AXL achieves the lowest values for keratometry and CD. The smallest value for CCT measurement is found with the OA-2000.

MicroRNA Pathological Mechanisms between Parkinson's Disease, Alzheimer's Disease, Glaucoma, and Macular Degeneration.

Reactive oxygen species (ROS) play an essential role in regulating various functions of organisms such as gene transcription, signalling transduction and immune response. However, overproduction of ROS can lead to oxidative stress, which is related to various ageing diseases including eye and brain degenerative diseases. Ocular measurements have recently been suggested as potential sources of biomarkers for the early detection of brain neurodegenerative diseases. MicroRNAs (miRNAs) are useful biomarkers for various diseases including degenerative diseases. miRNAs play an important role in the oxidative stress mechanisms of ageing diseases. In this paper, the role of miRNAs related to oxidative stress mechanisms in four ageing diseases, Parkinson's disease (PD), Alzheimer's disease (AD), glaucoma and age-related macular degeneration was reviewed. The common miRNA biomarkers related to the four diseases were also discussed. The results show that these eye and brain ageing diseases share many common miRNA biomarkers. It indicates that the ocular condition may be a prognostic biomarker for PD or AD patients. When a patient's eye condition changes, this can be a warning of a change in PD or AD status.

Digital Evaluation of the Changes in Eyelid and Ocular Surface Measurements and the Correlation of These Parameters with Visual Field Parameters After Upper Eyelid Blepharoplasty.

We aimed to evaluate the change in eyelid and ocular surface parameters that were measured using a digital measurement program, the change in the visual field (VF), and the correlation between ocular surface area (OSA) and VF parameters in patients who underwent upper eyelid blepharoplasty for involutional dermatochalasis. Patients who underwent upper eyelid blepharoplasty for involutional dermatochalasis between August 2015 and August 2019 were included in the study. The difference between preoperative and postoperative 3rd month values of manually measured margin reflex distance 1 (MRD1), digitally measured eyelid and ocular surface parameters (MRD1, MRD 2 [MRD2], upper eyelid crease height [ECH], pretarsal show height [PTH], eyebrow line-height [EBH] and OSA), and VF parameters were evaluated. The correlation between preoperative and postoperative values of manually and digitally measured MRD1 and also preoperative and postoperative values of OSA and VF parameters were analyzed. Thirty-six eyes from 36 patients were included in this study and the mean age of patients was 57.93±7.64 years. There were statistically significant changes between preoperative and postoperative values in means of the manually measured MRD1 and the digitally measured MRD1, PTH, OSA, and ECH (p<0.001). However, the postoperative changes in the mean MRD2 and EBH were not statistically significant (p=0.664 and p=0.983). There were moderate positive correlations between pre- and post-operative OSA values and pre- and postoperative values of manual and digital MRD1. A statistically significant agreement was observed between the change in OSA and the change in all VF parameters (Bland-Altman analysis test). Digital measurements can be used to evaluate the changes in eyelid and ocular surface parameters in patients who underwent upper eyelid blepharoplasty surgery. OSA provides fast results in accordance with linear measurements and is compatible with the change in the VF.

A Novel System for Ocular Surface Temperature Measurement and Tracking

A Novel System for Ocular Surface Temperature Measurement and Tracking

Minimum Ganglion Cell Layer Thickness is the Best Structural Predictor of Visual Function in Leber Hereditary Optic Neuropathy

Background: Patients with Leber hereditary optic neuropathy, a genetic cause of severe optic atrophy and blindness, demonstrate characteristic structural changes measurable through optical coherence tomography, including initial swelling of the retinal nerve fiber layer and progressive thinning of the ganglion cell layer. After symptomatic conversion, patients experience progressive vision loss, often with dense central scotomas. Aims: This study aims to explore the predictive potential of ocular structural measurements to visual function in patients with Leber hereditary optic neuropathy. Methods: Medical records were reviewed retrospectively for patients with Leber hereditary optic neuropathy clinical testing. Structural measurements, including the average thickness of the ganglion cell layer, the retinal nerve fiber layer, and minimum thickness of the ganglion cell layer, measured through optical coherence tomography were obtained along with measures of visual function such as visual acuity and mean deviation of visual field testing. Simple and multivariable linear regressions were performed to determine correlations between structural measurements and visual functions. Analyses were conducted for all patients, and subgroup of symptomatic patients. Results: Overall, 92 eyes were included with 78 symptomatic eyes. Across all patients, the minimum ganglion cell layer thickness had the highest correlation coefficient with visual acuity (Beta -0.632, adjusted R2 0.396) and with visual field function (Beta 0.572, adj. R2 0.320) compared to the average thickness of the ganglion cell layer (Beta 0.474, adj. R2 0.216) and retinal nerve fiber layer (Beta 0.481, adj. R2 0.223). In multivariate analysis, the minimum ganglion cell layer thickness was the only significant measurement that correlated with visual acuity across all eyes (Beta -0.527, P&lt;0.001) and symptomatic eyes (Beta -0.479, P&lt;0.001). The minimum ganglion cell layer thickness (Beta 0.440, P&lt;0.001) and retinal nerve fiber layer average thickness (0.258, P=0.023) were significant structural measurements correlating to visual field function. Conclusion: The minimum ganglion cell layer thickness is the best structural measure predictor for visual field and visual acuity compared to other common structural measurements in patients with Leber hereditary optic neuropathy. It is a good predictor even when evaluating only symptomatic eyes. Additional attention toward the minimum ganglion cell layer thickness may offer further insight into a patient’s visual potential and the natural history of this disease.

Relationship between plasma amino acid and carnitine levels and primary angle-closure glaucoma based on mass spectrometry metabolomics

World blindness is primarily caused by glaucoma. It has been predicted that by 2040, 118 million individuals will have glaucoma. Among Asians and Africans, primary angle-closure glaucoma (PACG) is the most prevalent type of glaucoma, for which treatment options are currently very limited. At present, lowering intraocular pressure (IOP) is the primary approach for PACG treatment. However, some PACG patients with decreased IOP measurements still advance. Additionally, because of the complicated pathophysiology, there are no biomarkers for diagnosis. Metabolomics is the study of the metabolites produced by all cellular processes in a biological sample, providing a method for identifying biomarkers and early diagnosis. Nevertheless, metabolomics has infrequently been applied to PACG. Previous research conducted by our lab on plasma metabolite fatty acids in PACG patients revealed reduced free fatty acid (FFA) levels, which may be connected to lipid peroxidation. To ascertain the relationship between other metabolites and PACG. We compared levels of amino acids and carnitine in patients with PACG (n = 147) and non-glaucoma (n = 340). Using metabolomics analysis, twenty-one amino acids and twenty-six carnitines (a total of ninety-six indicators) were examined. Odds ratios (OR) and 95% confidence intervals (CI) for these metabolites in relation to PACG were calculated. The relationship between ocular measures and metabolites was assessed by Spearman's rank correlation. Predictive performance was evaluated using the receiver operating characteristic (ROC). The C8/C2 level was comparable across patients with PACG and individuals without glaucoma based on the Wilcoxon rank-sum test. The PACG group had lower levels of Arginine (Arg), Ornithine (Orn), Arg/Orn, Orn/Cit, and C26/C20 than the nonglaucoma group, whereas Cit/Arg and C4/C2 ratios were greater. Both univariate and multivariate models showed a negative correlation between Orn and Orn/Cit and PACG. In the univariate model, palmitoylcarnitine (C16) had a negative correlation with PACG. According to our findings, metabolic profiles of plasma amino acids and carnitine between PACG patients and controls are different. The combination of amino acids and carnitine increased the predictive value of PACG. The Orn and Arg were negatively correlated with the local ocular neurodegenerative pathology. We speculate lipid peroxidation may explain the reduction in C16, and the decrease in Orn may be associated with hyperammonia neurotoxicity.

Relative Stability of Regional Facial and Ocular Temperature Measurements in Healthy Individuals.

Non-contact measurement of facial temperature using infrared thermography has been used for mass screening of body temperature during a pandemic. We investigated the relative stability of temperature measurement in different facial regions of healthy individuals. Twenty healthy subjects underwent two experiments. In the first experiment, subjects washed their faces with a 20°C wet towel for 1 minute. Temperature changes compared to baseline in the forehead, cornea, inner canthus, and outer canthus were determined using an infrared camera for 10 minutes. In the second experiment, lubricating eye drops at 20°C were instilled over one eye. Temperature changes in the same regions of interest were monitored for 5 minutes. Baseline temperatures before face washing in the forehead and cornea, inner canthus, and outer canthus of the right eye were 33.4°C ± 0.8°C (mean ± SD), 33.3°C ± 0.8°C, 34.3°C ± 0.7°C, and 32.8°C ± 0.7°C, respectively. Reductions in temperature due to face washing were most significant for the forehead and least significant for the cornea. One minute after face washing, the corresponding changes were -2.8°C ± 0.6°C, -0.3°C ± 0.6°C, -0.6°C ± 0.7°C, and -0.9°C ± 0.7°C for the forehead, cornea, inner canthus, and outer canthus, respectively. After administering the eye drops, no significant temperature changes were observed. When facial temperature was exogenously cooled, the cornea had the most stable temperature readings. When using infrared thermography to screen facial temperature, the measurement of corneal temperature is probably a better representative if the stability of temperature readings is critical.