BMJ Open Ophthalmology最新文献

Purpose: To investigate central Bowman's layer thickness (BT) in relation to central corneal thickness (CCT) and curvature, and epithelial thickness in healthy and disease corneas.

Methods: Patients with keratoconus (KC), corneal dystrophies (CD) and healthy controls (HC) were included. Linnik and Mirau versions of an ultra-high axial resolution line field spectral domain optical coherence tomography device were used to image the cornea, in addition to commercially available devices. A supervised automated segmentation process was used to extract the quasi-point thickness of Bowman's layer.

Results: 62 participants: 24 with KC, 20 with CD and 18 HC were included. Mean central BT was 15.41 µm (SD 0.49; min-max: 12.28-19.54) in HC, 14.27 µm (SD:0.43; min-max: 11.22-18.25) in KC and 15.65 µm (SD 0.64; min-max: 12.42-20.06) in CD (mainly Fuchs CD). Patients with KC had thinner central BT than those with CD (p=0.03), but not compared with HC (p=0.13). Central BT was significantly associated with CCT (p<0.01), being on average 3% of CCT. The ratio of BT to CCT was independent of diagnosis (CD 0.028, HC 0.030, KC 0.028, p=0.88), age (p=0.23), sex (p=0.67), Kmax (p=0.77) or epithelial thickness (p=0.72).

Conclusions: Over sample populations of healthy, keratoconic and dystrophic corneas, central BT was consistently associated with corneal thickness and was independent of age, sex, Kmax, and epithelial thickness.

Trial registration number: ISRCTN40558.

Introduction: Myopia and its complications can lead to irreversible visual impairment and even blindness, making this a worldwide public health concern for the 21st century. While treatments to slow myopia progression exist, their average efficacy is moderate. Bright light exposure, either in controlled animal models or naturally under sunlight for children, has demonstrated a protective effect against myopia development. This study hypothesises that bright light therapy (BLT), delivered via a home-based device mimicking sunlight, could slow myopia progression in schoolchildren.

Methods and analysis: We propose a 2-year, double-masked, randomised controlled trial to investigate the effectiveness of BLT and its combination with myopia control treatment in schoolchildren. Chinese schoolchildren aged 7-12 years will be recruited and randomly assigned to one of three arms in phase 1. Subjects will be instructed to perform a minimum of 45 mins of near tasks daily under either BLT (10 000 lux white Light Emitting Diode (LED) light) or placebo light therapy (500 lux white LED light). The control subjects will receive single-vision spectacles and placebo light therapy; the single treatment subjects will receive single-vision spectacles and BLT; and the combination treatment subjects will receive defocus-incorporated multiple segments spectacles and BLT. The primary and secondary outcome measures are changes in cycloplegic objective refraction and axial length over a 2-year period.Treatment dosage is indirectly measured using a monitoring sensor attached beneath the BLT lamp rather than a wearable light metre. Variations in dosage monitoring may influence the observed treatment efficacy.

Ethics and dissemination: The study has been approved by the Institutional Review Boards of The Hong Kong Polytechnic University (HSEARS 20180829002-05) and The University of Hong Kong/Hospital Authority Hong Kong West Cluster (UW 20-362). The study results will be disseminated in scientific conferences and peer-reviewed indexed journals.

Trial registration number: ClinicalTrials.gov identifier: NCT04923841.

Aims: This cross-sectional study aimed to determine the prevalence of glaucoma and associated ocular characteristics in Thai patients with Naevus of Ota, comparing those with ocular melanocytosis or oculodermal melanocytosis to those exhibiting only skin hyperpigmentation.

Methods: Patients who were diagnosed with Naevus of Ota at Siriraj Hospital, Thailand, underwent a comprehensive ophthalmic assessment by a glaucoma specialist. Those unable to cooperate in an outpatient setting were examined under general anaesthesia. The assessments comprised visual acuity, intraocular pressure (IOP), anterior segment findings, gonioscopy, corneal diameter (in patients aged <3 years) and fundus examination. Visual field and optical coherence tomography tests were performed as indicated.

Results: A total of 163 patients (184 eyes) were examined, including 115 eyes with ocular melanocytosis or oculodermal melanocytosis. The mean age at examination was 15.0±15.6 years. Open-angle glaucoma was identified in 2 eyes (1.1%), ocular hypertension in 6 eyes (3.3%) and glaucoma suspicion in 16 eyes (8.7%). Among those with ocular melanocytosis or oculodermal melanocytosis, ocular hypertension and glaucoma suspicion were more common (4.3% and 12.2%, respectively) than in those with only skin hyperpigmentation (1.4% and 2.9%, respectively).

Conclusion: Although the prevalence of glaucoma in Naevus of Ota is low, patients with ocular melanocytosis or oculodermal melanocytosis are at greater risk of ocular hypertension and suspected glaucoma than are those with skin-only hyperpigmentation. Targeted screening, particularly in younger individuals and those requiring examination under general anaesthesia, should be considered. The main limitation of the study is its cross-sectional design, offering only a one-time view of a prolonged clinical progression. Moreover, the use of anaesthetic inhalation could have resulted in lower IOP readings during general anaesthesia.

Trial registration number: TCTR20210223004.

Aims: To determine the associations between measures of oestrogen exposure and Fuchs endothelial corneal dystrophy (FECD) severity.

Methods: Clinic-based cross-sectional study of 32 postmenopausal women and 11 men with mild or severe FECD, age>55 years. Participants completed questionnaires for data on demographics, anthropometric factors, medical history and potential risk factors for FECD. Women completed an additional reproductive history questionnaire used to calculate the months of lifetime oestrogen exposure. Slit-lamp biomicroscopy, specular microscopy, corneal Scheimpflug tomography and laboratory testing (TCF4 repeat expansion quantification, total estradiol, free estradiol, sex hormone binding globulin (SHBG), calcaneal bone density) were performed. Logistic regression models were developed to predict FECD severity based on three-way interactions of each oestrogen exposure measure, sex and TCF4 genotype.

Results: 43 patients were enrolled in the study (mild FECD: 17 women, 3 men; severe FECD: 15 women, 8 men). Serum-free estradiol was higher in the severe compared with mild FECD group (0.21±0.2 vs 0.09±0.1 pg/mL; p=0.046). When stratified by sex, men showed no significant associations between oestrogen measures and FECD severity. However, in women, the odds of severe FECD were increased with more months of lifetime oestrogen exposure (all women; log OR (95% credible interval): 1.3 (0.14 to 4.3)), higher concentrations of free estradiol (all women; 2.1 (0.0049 to 10)), greater % free estradiol (only women without TCF4 repeat expansion; 1.3 (0.16 to 3.8)) and higher concentrations of SHBG (only women with TCF4 repeat expansion; 2.2 (0.45 to 9.1)).

Conclusions: While the application of these data is constrained by the limited number of participants, a clinic-based sample, small number of men compared with women and single-point measures of serum hormone measures, these data suggest that FECD severity is associated with higher oestrogen exposures in women but not men and may be dependent on TCF4 repeat expansion status.

Objective: This study validated the artificial intelligence (AI)-based algorithm LuxIA for screening more-than-mild diabetic retinopathy (mtmDR) from a single 45° colour fundus image of patients with diabetes mellitus (DM, type 1 or type 2) in Spain. Secondary objectives included validating LuxIA according to the International Clinical Diabetic Retinopathy (ICDR) classification and comparing its performance between different devices.

Methods: In this multicentre, cross-sectional study, retinal colour fundus images of adults (≥18 years) with DM were collected from five hospitals in Spain (December 2021-December 2022). 45° colour fundus photographs were captured using non-mydriatic Topcon and ZEISS cameras. The Discovery platform (RetinAI) was used to collect images. LuxIA output was an ordinal score (1-5), indicating a classification as mtmDR based on an ICDR severity score.

Results: 945 patients with DM were included; the mean (SD) age was 64.6 (13.5) years. The LuxIA algorithm detected mtmDR with a sensitivity and specificity of 97.1% and 94.8%, respectively. The area under the receiver-operating characteristic curve was 0.96, indicating a high test accuracy. The 95% CI data for overall accuracy (94.8% to 95.6%), sensitivity (96.8% to 98.2%) and specificity (94.3% to 95.1%) indicated robust estimations by LuxIA, which maintained a concordance of classification (N=829, kappa=0.837, p=0.001) when used to classify Topcon images. LuxIA validation on ZEISS-obtained images demonstrated high accuracy (90.6%), specificity (92.3%) and lower sensitivity (83.3%) as compared with Topcon-obtained images.

Conclusions: AI algorithms such as LuxIA are increasing testing feasibility for healthcare professionals in DR screening. This study validates the real-world utility of LuxIA for mtmDR screening.

Objective: To assess the interchangeability of minimum linear diameter (MLD) macular hole (MH) size measurements in high-density horizontal and radial scan modes in optical coherence tomography (OCT).

Methods and analysis: 60 patients with a MH had repeat high-density OCT volume scans in a horizontal (30 µm interscan-spacing) and a radial (angular 3.75° interscan-spacing) mode, and the MLD was measured by five raters.

Results: There were no significant differences in the MLD measurements within the horizontal and the radial modes across repeat measurements of each rater in volume scan 1 (all p≥0.14 and p≥0.28, respectively), between volume scans 1 and 2 (all p≥0.14 and p≥0.69), among the raters (p=0.70 and p=0.60), and using all MLD measurements obtained in this study between primary and repeat measurements in volume scan 1 (p=0.10 and p=0.74) and between measurements obtained in volume scan 1 and 2 (p=0.21 and p=0.90).There was a statistically significant difference of -10.05 µm between the mean MLD of all measurements in the horizontal (n=900) and in the radial (n=900) mode (427.91 (±187.01) vs 437.97 (±184.93) µm; p<0.001). However, the variability of these differences around the mean MLD was large (95% limits of agreement -77.31 to 57.21 µm). The mean difference between all horizontal and all radial MLD measurements in a MH was for MHs that had their widest MLD within 15° of the horizontal, vertical and diagonal meridians 0.77 (±13.88) µm, -34.43 (±55.22) µm and -10.39 (± 34.62) µm, respectively.

Conclusions: Horizontal scans systematically underestimate the maximum MLD if located vertically or diagonally; however, they have less intra-rater and inter-rater and inter-scan variability in MLD measurements as compared with radial scans. Therefore, the two scan modes are not interchangeable but rather complement each other. These results may be limited to the MLD range analysed (125-924 µm).

Background: A novel classification for microspherophakia (MSP) was developed using a nomogram model to stratify patients and evaluate surgical outcomes.

Methods: The study involved 99 eyes from 64 MSP patients, divided into training (64 eyes) and validation (35 eyes) cohorts. Primary outcome included the best corrected distance visual acuity (BCVA) at the 1-year follow-up, and the secondary outcome was intraocular pressure (IOP) control. MSP patients achieving a BCVA of ≤0.2 logarithm of the minimal angle of resolution with successful IOP control were categorised into the favourable outcomes group, while those not meeting these criteria were placed in the unfavourable outcomes group. A nomogram model was constructed to predict unfavourable outcomes by identifying associated risk factors.

Results: In the training cohort, 39.06% (25/64) achieved favourable outcomes, while 60.94% (39/64) had unfavourable outcomes. Decreased anterior chamber depth (ACD) and the presence of glaucoma were identified as risk factors for predicting unfavourable outcomes. The concordance index for the training and validation cohorts was 0.828 and 0.768, respectively. A nomogram-derived cut-off value of 56 points stratified patients into low-risk (≤56 points) and high-risk (>56 points) groups. Postoperative BCVA was significantly better in the low-risk group at 6-month and 1-year follow-ups.

Conclusion: MSP patients in the low-risk group achieved satisfactory outcomes. For high-risk patients with shallowing ACD, early surgical intervention is recommended to prevent secondary glaucoma. Close monitoring of IOP and glaucoma progression is crucial for patients with secondary glaucoma. This classification offers valuable insights for outcome stratification and guidance in clinical decision-making for MSP management. However, the limitations of this study include its small sample size, which may impact generalisability, and future studies with larger cohorts are needed to validate and refine the nomogram.