To test inter-observer variation of plus disease diagnoses among Norwegian ophthalmologists and treatment centres. All ophthalmologists in Norway who make individual retinopathy of prematurity (ROP) treatment decisions were invited to grade retinal images using a web-based image grading platform. The images (n = 180) were a subset from the US Imaging and Informatics in Retinopathy of Prematurity (i-ROP) study and were either normal, with pre-plus disease, or plus disease. Agreement both between ophthalmologists and between the five different centres in Norway with a reference standard diagnosis (RSD) was measured through weighted kappa (k) and percent agreement (PA). Agreement with the US RSD was also measured. Each image was associated with an artificial intelligence-based Vascular Severity Score (VSS) ranging from 1 to 9, and the VSS agreement rate for each score was compared. All invited ophthalmologists (n = 15, of which six from the largest centre and two to three from each of the other four centres) agreed to participate. Agreement between ophthalmologists and the Norwegian RSD ranged from moderate (k = 0.458) to near perfect (k = 0.844), and from substantial (k = 0.679) to near perfect (k = 0.802) between consensus diagnosis at each centre and the Norwegian RSD. The agreement between centres and the US RSD ranged from moderate to substantial (κ = 0.561-0.729). Overall inter-observer variability in Norway was low. Such variability is therefore unlikely to explain regional differences in the frequency of treated ROP in Norway.

To assess prevalence and associations of intra-vitreal hyper-reflective bodies (vHRBs) in the posterior vitreous in a general population. Participants of the population-based Beijing Eye Study underwent systemic and ophthalmological examinations. We included into this study a randomly selected group of normal eyes without retinal diseases and a randomly selected group of eyes with age-related macular degeneration (AMD), polypoidal choroidal vasculopathy (PVC) or central serous choroidopathy (CSC). Using serial optical coherence tomography scans of the posterior fundus region, we searched for vHRBs in the posterior vitreous compartment. The study consisted of 1347 eyes (age: 64.3 ± 9.8 years, range: 50-91 years; axial length: 23.04 ± 1.00 mm, range: 19.39-28.93 mm). vHRB were detected in 314/1347 eyes (23.3%; 95% confidence interval [CI]: 21.1, 25.6), that is, in 137 out of 447 normal eyes (28.9%; 95% CI: 24.8, 33.0), 110/458 eyes with early AMD (24.0%; 95% CI: 20.1, 27.9), 45/278 eyes with intermediate AMD (16.2%; 95% CI: 11.8, 20.5), 3/35 eyes with PCV (8.6%; 95% CI: 0.00, 18.3), and in 19/94 eyes with CSC (20.2%; 95% CI: 11.9, 28.5). In multivariable analysis, higher vHRB prevalence was associated with younger age (OR: 0.93; 95% CI: 0.91, 0.95; p < 0.001), shorter axial length (OR: 0.69; 95% CI:0.56, 0.84; p < 0.001), and lower stage of posterior vitreous detachment (OR: 0.53; 95% CI: 0.44, 0.64; p < 0.001). It was independent of AMD stage (p = 0.87), and prevalence of PCV (p = 0.67) and CSC (p = 0.40). Higher amount of vHRBs (multivariable linear regression analysis) correlated with younger age (beta: -0.21; B: -0.02; 95% CI: -0.03, -0.02; p < 0.001), shorter axial length (beta: -0.07; B: -0.09; 95% CI: -0.16, -0.02; p = 0.009) and lower stage of posterior vitreous detachment (beta: -0.15; B: -0.13; 95% CI: -0.19, -0.08; p < 0.001). vHRBs were detected in one out of four normal eyes of individuals aged 50+ years, in dependence on younger age, shorter axial length and lower degree of posterior vitreous detachment. They were independent of a concurrence of AMD, PCV and CSC.

This thesis presents a comprehensive analysis of vision screening of children in Greenland, focusing on the efficacy of the current programme for six-year-old schoolchildren, the prevalence of vision impairment, amblyopia and refractive errors among six- and four-year-old children and the evaluation of a new screening method for preschool children. Additionally, it underscores the challenges of delivering consistent healthcare services in Greenland due to its vast and sparsely populated areas and the lack of prior research on vision health in Greenlandic children. The thesis involved three populations: two groups of six-year-old children, one with 2493 children from 2017 to 2022 and another with 517 children in 2017, and one group of 274 four-year-old children, all born in 2017. Key findings include an increase in screening coverage of schoolchildren from 43% to 61% from 2017 to 2022, although referral rates to ophthalmologists declined in the same period from 14% to 5% due to system inefficiencies. The prevalence of monocular amblyopia (≥0.3 logMAR) was 2% for both age groups, consistent with European and North American data. The prevalence of vision impairment was steady throughout the study period at 3% for the six-year-old children. Notably, Greenlandic children exhibit less severe vision impairment than in other regions, potentially due to genetic or environmental factors. However, they exhibited more hyperopia than African American and Chinese children but less than White American and Danish children. They also had higher myopia rates compared to Danish and indigenous Canadian children. The thesis highlights the importance of early detection and intervention for optimal visual development, emphasising a tailored approach for Greenlandic children. Improvements to the screening programme are suggested, including clear referral instructions, involvement of various healthcare professionals, such as optometrists, and enhanced parental awareness to increase coverage and ensure timely evaluations. It also suggests a new screening method incorporating a non-cycloplegic autorefraction to enhance the sensitivity and effectiveness of preschool children. Recommendations for screening methods and referral criteria for six- and four-year-olds are provided, along with an outline of the estimated costs of the new screening method. This thesis provides a basis for helping decision-makers in Greenland improve vision screening for Greenlandic children. Future research directions include assessing the quality of life of children with vision impairments, exploring the genetic and environmental determinants of myopia and leveraging technology to improve access to vision care for children in Greenland.

This study aims to evaluate the performance of the telemedicine retinopathy of prematurity severity score (tROP-SS) across all 14 NICUs in the TELEROP cohort against the modified ROP activity score (mROP-ActS). Retrospective cohort study. The study included 2037 neonates who underwent ROP screening in 14 NICUs via the TELEROP telemedicine network from November 2017 to January 2025. We compared the robustness of tROP-SS and mROP-Act systems across all exams. The primary outcomes studied were the ability to return a score in cases responding to treatment, correlation between the two scores and the ability to assess disease directionality. The study analysed 192 704 photos from 11 368 ROP exams on 2037 patients. tROP-SS generated scores for 100% of exams, demonstrating significant improvements over mROP-ActS, which scored only 92.3% of all exams (p = 0.0136). All patients who met treatment criteria received treatment in both eyes. Among high-risk and treatment warranted (TW) patients, 100.0% exams had a valid tROP-SS exam compared with only 72.73% and 45.27% with a valid mROP-ActS. Only 20.9% high-risk or TW patients had a valid mROP-ActS across all their exams. Incremental increases in tROP-SS were more strongly related to worsening of disease: OR (95% CI) - 3.37 (2.51-4.53) versus 1.57 (1.46-1.69), both p < 0.0001. tROP-SS also demonstrated improved granularity and accuracy in categorizing patients that would ultimately require treatment (AUC: 0.991 vs. 0.825). tROP-SS was retrospectively evaluated across 14 NICUs, proving to be a more robust scoring system compared to mROP-ActS. The findings support continued use of tROP-SS, supplemented by standard screening protocols to ensure no cases of treatment-warranted ROP are missed. Future research may focus on integrating additional parameters to enhance predictive models to improve early ROP detection.

To examine axial length as a risk factor for pseudophakic rhegmatogenous retinal detachment (pRRD). We identified eyes that underwent phacoemulsification between 2 May 2002 and 10 November 2023 and had an axial length registered at the Departments of Ophthalmology in the Capital Region of Denmark or the private clinic Scandinavian Eye Center. The exposure was axial length, and the outcome was time from phacoemulsification to the occurrence of pRRD. The cumulative incidence of pRRD was estimated with the Aalen-Johansen estimator. We included 129 362 eyes from 75 316 individuals; 601 eyes developed a pRRD. The eyes were distributed in groups based on axial length: <24 mm: 84 226, 24-25 mm: 38 331 and ≥26 mm: 6805. The hazard of pRRD increased with axial length, and this association was most pronounced in males. Compared to female eyes with an axial length of <24 mm (reference), male eyes of ≥26 mm had a higher hazard of pRRD (hazard ratio (HR) 16.3; 11.8-22.5), and likewise for female eyes of ≥26 (HR: 5.2; 3.3-8.1) after adjustment for age and including an interaction between axial length and sex. The 5-year cumulative incidence of pRRD among male eyes of ≥26 mm undergoing phacoemulsification between the ages 40 and 59 was 9.40% (95%CI: 7.10-12.50), and among male eyes aged ≥60 and of ≥26 mm it was 2.00% (95%CI: 1.50-2.70). The risk of pRRD increased with axial length, and this association was most pronounced in male eyes. The risk of pRRD was high among male eyes that underwent phacoemulsification between ages 40 and 59.

The Central Nervous System (CNS), comprising the brain and the eye, is considered to have a 'privileged' mechanism for dealing with immunological challenge (immune privilege, IP). CNS IP has been revealed through experiments using foreign protein antigens and cell and tissue alloantigens (grafts), but evidence for a role for IP in modulating host-pathogen interactions in the CNS is limited. However, the low frequency of CNS infection in the face of widespread systemic exposure to CNS-tropic infectious agents, together with the high incidence of CNS infection in immunocompromised individuals, suggests that in healthy individuals, the CNS has tightly controlled regulatory mechanisms to protect against infectious agents. Although the naïve healthy brain and retina parenchyma largely lack adaptive immune cells, their border tissues (meninges, uveal tract) contain a full complement of resident immune cells, including CNS-specific regulatory T cells (Tregs), which have a fundamental role in controlling infection in the brain parenchyma. Tregs also underpin ocular IP, particularly of the neural retina. Recent studies report that Tregs are transcriptionally 'customised' to the CNS and function at a distance; that is, are located in niches/hubs around the venous sinuses of the border tissues. T cells resident in the uveal tract probably play a similar role. We propose that Tregs are key drivers of CNS IP and do so by promoting latency of infectious agents.

Conventional optical coherence tomography (OCT) has a floor effect in patients with severe visual field loss, such as seen in advanced primary open-angle glaucoma (POAG). OCT angiography (OCTA) does not suffer from such a floor effect. However, which OCTA parameters are most useful for monitoring longitudinal progression is unclear. We conducted a systematic review and meta-analysis to investigate the clinical use of OCTA in monitoring the progression of intermediate and advanced POAG by searching four databases (Medline, Embase, Web of Science and Cochrane Database of Systematic Reviews) for longitudinal studies on POAG and OCTA. For each meta-analysed OCTA parameter, we calculated a pooled effect estimate with a 95% confidence interval (95% CI). Parameters that could not be meta-analysed were compared narratively. A total of 18 studies were included in the systematic review and seven in the meta-analyses. In the meta-analyses, a lower baseline peripapillary vessel density (VD) significantly increased the risk of visual field (VF) progression (HR [95% CI]: 1.05 [1.02, 1.07] for each percentage decrease in peripapillary VD per year). Baseline parafoveal VD and risk of VF progression showed no significant association. The inferior hemifield foveal avascular zone parameters and the presence of peripapillary choroidal microvascular dropout were significantly associated with the risk of VF progression in the systematic review. Peripapillary VD may be a useful predictor of VF progression in intermediate and advanced glaucoma patients. Although FAZ and MvD also seem to be potential predictors, longitudinal studies on advanced POAG are limited and heterogeneous, highlighting the need for more consistent and comprehensive research.

To compare the effect of preoperative Nd:YAG laser peripheral iridotomy (PI) and intraoperative surgical iridectomy on subclinical inflammation before and after Descemet membrane endothelial keratoplasty (DMEK), using validated anterior segment optical coherence tomography (AS-OCT) inflammatory biomarkers. Among 132 eyes eligible for analysis, this matched cohort study included 40 eyes (20 per group) undergoing DMEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy. Patients received either a preoperative laser PI or intraoperative surgical iridectomy. Eyes were matched according to gender, age, presence of preoperative posterior stromal ripples, baseline visual acuity and corneal thickness. Pre- and post-operative inflammation was quantified using AS-OCT measured aqueous-to-air relative intensity (ARI) and anterior chamber (AC) cell reflectivity. Post-operative trends in subclinical inflammation were compared using generalized additive models (GAM). Visual, pachymetric and endothelial outcomes, as well as post-operative complications, were compared. The laser PI group showed greater baseline ARI (p < 0.001) consistent with higher preoperative subclinical inflammation, while surgical iridectomy eyes exhibited greater cell counts after DMEK and at final follow-up (both p = 0.05). Post-operative inflammatory spikes resolved by 6-8 weeks, with faster normalization and lower peak values in the laser PI group. Visual acuity improvement, central corneal thickness reduction, endothelial cell loss and complication rates were comparable. Preoperative laser PI was associated with lower early post-operative subclinical inflammation compared with intraoperative surgical iridectomy, without compromising visual or endothelial outcomes. These findings suggest that a less invasive PI approach may mitigate early post-operative immune activation, promoting smoother AC homeostasis after DMEK.

To evaluate changes in corneal tomography, pachymetry and endothelial cell density (ECD) following Paul Glaucoma Implant (PGI) surgery. Seventy-three patients were prospectively examined. Repeated measures anova was used to analyse corneal tomography, corneal thickness and ECD at baseline, 6 and 12 months. PGI surgery was not associated with clinically meaningful changes in corneal tomography parameters. Simulated astigmatism and posterior astigmatism remained stable over 12 months. Simulated average keratometry showed a small but statistically significant flattening (≈0.3 diopters), whereas posterior average keratometry remained unchanged. Although some changes reached statistical significance, their magnitude was minimal and unlikely to be clinically relevant. Central corneal thickness remained stable, but pachymetry in the tube quadrant increased in the operated eyes, while adjusted pairwise comparisons were non-significant. Central ECD did not change significantly after surgery (p = 0.67). In contrast, paracentral (-2.9%) and peripheral (-4.7%) ECD values declined significantly over 12 months (p = 0.03 and p = 0.001, respectively) and study eyes consistently showed lower values than contralateral control eyes. However, PGI surgery did not accelerate the rate of cell loss, as the time × eye interaction was not significant. PGI surgery did not induce progressive changes in corneal astigmatism or pachymetry during the first postoperative year. Central ECD remained stable, while paracentral and peripheral regions showed a moderate decline. PGI did not increase the rate of endothelial cell loss and the observed reduction was lower than previously reported for other glaucoma drainage implants.