Pulsed corneal crosslinking in the treatment of Keratoconus: a systematic review and meta-analysis.

PURPOSE: Corneal crosslinking (CXL) procedures are the treatment of choice in halting progressive corneal ectasia and preserving visual acuity due to keratoconus. Pulsed crosslinking (P-CXL) was developed using intermittent pulsing ultraviolet (UV) light to mitigate the depletion of oxygen levels that occurs with continuous UV exposure in standard crosslinking protocols (C-CXL). This study aimed to explore the use of P-CXL in the treatment of keratoconus and determine whether the availability of oxygen in P-CXL carries superior efficacy outcomes as an alternative to C-CXL modalities. METHODS: This review was undertaken in accordance with PRISMA guidelines. A search of several databases conducted with two separate reviewers resulted in 29 papers meeting inclusion criteria for the review, 14 selected for meta-analysis. Primary outcomes assessed by the included papers included maximum keratometry (Kmax), corrected and uncorrected distance visual acuity (CDVA, UDVA), and secondary outcomes included central corneal thickness (CCT), endothelial cell count and demarcation line. Statistical analyses were carried out on Review Manager 5.4 and the meta-analysis employed a random-effects model, which estimated the weighted effect size of raw means using inverse variance weights. RESULTS: At 12 months P-CXL showed statistically significant reductions in Kmax (-0.75 D; p < 0.001) and improvement in CDVA (-0.10 logMAR; p < 0.001) compared to baseline. The meta-analysis of comparative studies determined that mean differences in Kmax, CDVA, UDVA, Kmean and CCT after 12 months were not statistically significant between pulsed and continuous crosslinking groups. CONCLUSIONS: Overall, P-CXL is effective in improving visual acuity and keratometry outcomes in keratoconus. The meta-analysis did not show a statistically significant difference in Kmax and CDVA between P-CXL and C-CXL, indicating a non-inferiority of P-CXL. However, findings of the meta-analysis are limited by the fact that different energy levels and exposure times were used for P-CXL in comparison to C-CXL in some studies, making it unsuitable to determine whether the efficacy of CXL is improved by the use of pulsed light. KEY MESSAGES: What is Known • Pulsed crosslinking (P-CXL) uses intermittent UV light to prevent oxygen depletion when using higher energy protocols, unlike continuous UV exposure in standard continuous crosslinking (C-CXL). • This should theoretically enhance the efficacy of the treatment by maintaining higher oxygen levels that are crucial to the cross-linking process. • There are no systematic reviews or meta-analyses directly comparing the efficacy or safety of P-CXL to C-CXL. What is New • Meta-analysis revealed differences in keratometry between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (Kmax -0.04 dioptres; p = 0.84). • Meta-analysis revealed differences in visual acuity between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (CDVA -0.01 logMAR letters; p = 0.57). • The use of intermittent pulsing in higher energy CXL protocols renders statistically similar outcomes as continuous light exposure at equivalent fluence (7.2 J/cm2).

Artificial Intelligence and Ophthalmic Clinical Registries.

PURPOSE: The recent advances in artificial intelligence (AI) represent a promising solution to increasing clinical demand and ever limited health resources. Whilst powerful, AI models require vast amounts of representative training data to output meaningful predictions in the clinical environment. Clinical registries represent a promising source of large volume real-world data which could be used to train more accurate and widely applicable AI models. This review aims to provide an overview of the current applications of AI to ophthalmic clinical registry data. DESIGN AND METHODS: A systematic search of EMBASE, Medline, PubMed, Scopus and Web of Science for primary research articles that applied AI to ophthalmic clinical registry data was conducted in July 2024. RESULTS: Twenty-three primary research articles applying AI to ophthalmic clinic registries (n = 14) were found. Registries were primarily defined by the condition captured and the most common conditions where AI was applied were glaucoma (n = 3) and neovascular age-related macular degeneration (n = 3). Tabular clinical data was the most common form of input into AI algorithms and outputs were primarily classifiers (n = 8, 40%) and risk quantifier models (n = 7, 35%). The AI algorithms applied were almost exclusively supervised conventional machine learning models (n = 39, 85%) such as decision tree classifiers and logistic regression, with only 7 applications of deep learning or natural language processing algorithms. Significant heterogeneity was found with regards to model validation methodology and measures of performance. CONCLUSIONS: Limited applications of deep learning algorithms to clinical registry data have been reported. The lack of standardized validation methodology and heterogeneity of performance outcome reporting suggests that the application of AI to clinical registries is still in its infancy constrained by the poor accessibility of registry data and reflecting the need for a standardization of methodology and greater involvement of domain experts in the future development of clinically deployable AI.

Impacts of keratoconus on quality of life: a qualitative study.

BACKGROUND/AIMS: To identify the domains of quality of life (QoL) in people with keratoconus. METHODS: Semi structured in-depth in person and telephone interviews were conducted with participants diagnosed with keratoconus and recruited from the Sydney Eye Hospital, Sydney, Australia. Thematic analysis of interview content was conducted using inductive and deductive processes. Data was collected until thematic saturation was obtained. RESULTS: 33 patients with keratoconus with median age 37 (range 18 to 65) years and majority male (n = 25; 75.8%) were interviewed and a total of 2551 quotes coded. Thematic analysis resulted in 7 broad themes, Driving (199 references), Career (259 references), Symptoms (647 references), Enjoyment (149 references), Relationships (250 references), Financial (104 references) and Healthcare (881 references). Most references described a negative relationship between keratoconus and these 7 domains. The diverse QoL issues expressed included frustration with treatment effectiveness, fear of disease progression, inconvenience with contact lenses, forced career changes and job loss, cost of contact lenses, and feelings of isolation and discrimination. Themes and subthemes described a complex and varied relationship between keratoconus and QoL. CONCLUSION: Severe quality of life impairment was experienced by keratoconus patients despite treatment. Keratoconus diminishes various aspects of individual's QoL. Therapies able to improve QoL are still needed for keratoconus.

Intereye Asymmetry as a Predictor of Progression in Patients With Untreated Keratoconus: Findings From a Longitudinal Study.

PURPOSE: The purpose of this study was to evaluate interocular predictors of progression in patients with untreated keratoconus. METHODS: This is a multicenter longitudinal observational study with real-world data collected through the Save Sight Keratoconus Registry. Patients between the period of June 2000 and September 2022 were included in this study. Parameters such as patient age, sex, ocular history, visual acuity, K2, Max-K, and thinnest corneal thickness pachymetry (TCT) were analyzed. RESULTS: There were 4342 untreated eyes from 2171 patients with keratoconus. A total of 333 patients showed progression of either Max-K, TCT, or both, whereas 1838 patients showed stable parameters. Factors associated with a higher incidence of progression in Max-K were younger baseline age (HR 0.96 per year older; 95% CI 0.95-0.98, P < 0.0001) and a higher baseline intereye asymmetry in Max-K (HR 1.02 per higher diopter; 95% CI 1.00-1.04, P = 0.04). A younger baseline age was the only predictor of progression in TCT (HR 0.97 per year older; 95% CI 0.95-0.99, P = 0.001). CONCLUSIONS: Age is the most significant predictor of progression for both corneal thinning and progression of Max-K. Interocular asymmetry in Max-K at baseline could be used as part of an algorithm for determining the risk of keratoconus progression. It is recommended that patients with higher interocular asymmetry in Max-K have a closer follow-up of both eyes as they are at a higher risk of progression.

Ocular Injuries After Bungee Jumping.

We present a case of ocular injuries post bungee jumping in Nepal. A 26 year old female presented to our clinic with bilateral Sub Conjunctival Hemorrhage (SCH) after bungee jumping. Her best corrected visual acuity was 20/20 in both eyes. No other intraocular hemorrhage was revealed in her dilated ocular examination. Conservative treatments with artificial tears were given to her and follow up visit after one week was advised. The SCH was resolved after a treatment of one week. Her visual acuity remained stable and no other ocular complications were found. To conclude, bungee jumping can be the cause of several ocular injuries. Further studies are required to identify the causes and potential risk factors. Keywords: Bungee jumping, ocular injury; sub conjunctival haemorrhage.

BCLA CLEAR Presbyopia: Epidemiology and impact.

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

Antimicrobial resistance in ocular infection: A review.

Antimicrobial resistance (AMR) is a global public health threat with significant impact on treatment outcomes. The World Health Organization's Global Action Plan on AMR recommended strengthening the evidence base through surveillance programs and research. Comprehensive, timely data on AMR for organisms isolated from ocular infections are needed to guide treatment decisions and inform researchers and microbiologists of emerging trends. This article aims to provide an update on the development of AMR in ocular organisms, AMR in bacterial ocular infections and on AMR stewardship programs globally. The most common ocular pathogens are Pseudomonas aeruginosa, Staphylococcus spp., Streptococcus pneumoniae, and Haemophilus influenzae in ocular infections. A variety of studies and a few surveillance programs worldwide have reported on AMR in these infections over time. Fluoroquinolone resistance has increased particularly in Asia and North America. For conjunctivitis, the ARMOR cumulative study in the USA reported a slight decrease in resistance to ciprofloxacin. For keratitis, resistance to methicillin has remained stable for S. aureus and CoNS, while resistance to ciprofloxacin has decreased for MRSA globally. Methicillin-resistance and multidrug resistance are also emerging, requiring ongoing monitoring. Antimicrobial stewardship (AMS) programmes have a critical role in reducing the threat of AMR and improving treatment outcomes. To be successful AMS must be informed by up-to-date AMR surveillance data. As a profession it is timely for ophthalmology to act to prevent AMR leading to greater visual loss through supporting surveillance programmes and establishing AMS.

Comparison of standard versus accelerated corneal collagen cross-linking for keratoconus: 5-year outcomes from the Save Sight Keratoconus Registry.

OBJECTIVE: To compare long-term effectiveness of Standard (UV intensity: 3 mW/cm2, duration: 30 min) vs Accelerated (UV intensity: 9 mW/cm2, duration: 10 min) corneal cross-linking (CXL) for stabilising keratoconus. METHODS: Data for this observational study were captured through a web-based registry system from the routine clinical practice (15 sites across Australia, New Zealand and Italy). The outcomes were compared using mixed-effects regression models. A total of 100 eyes (75 patients) who had standard CXL and 76 eyes (66 patients) who had accelerated CXL, with a follow-up visit at five-year post-CXL were included. RESULTS: Both CXL protocols were effective and safe in stabilising keratoconus and improving outcomes. The adjusted mean changes (95% CI) in outcomes were better in standard CXL than in accelerated CXL [visual acuity gain, 10.2 (7.9-12.5) vs 4.9 (1.6-8.2) logMAR letters; pinhole visual acuity 5.7 (3.5-7.8) vs 0.2 (-2.2 to 2.5) logMAR letters; Kmax -1.8 (-4.3 to 0.6) vs 1.2 (-1.5 to 3.9)D; K2 -0.9 (-2.2 to 0.3) vs 0.1 (-1.3 to 1.6)D; MCT -3.0 (-13.7 to 7.7) vs -11.8 (-23.9 to 0.4) µm (p values for visual acuity, pinhole visual acuity, Kmax: <0.05; for K2 and MCT: >0.05)]. The frequency of adverse events at the 5-year follow-up visit was low in both groups [standard, 5 (5%; haze 3; scarring 1, epithelial defect 1) and accelerated 3 (3.9%; haze 2, scarring 1)]. CONCLUSIONS: Both standard and accelerated CXL were safe and effective procedures for stabilising keratoconus in the long term. The standard CXL resulted in greater improvements in visual acuity and keratometry.

Access to eye care among adults from an underserved community in Aotearoa New Zealand.

CLINICAL RELEVANCE: In all countries, there are population groups that are underserved by eye health services. By exploring access to eye care for these communities, optometrists and other eye care providers can promote equitable access to quality eye care, including strengthening patient relationships, and championing inclusive, people-centred services. BACKGROUND: New Zealand has very few policies to enable access to primary eye health services. The aim of this study was to explore the barriers and facilitators to accessing eye health services among adults from an underserved community in Auckland. METHODS: A qualitative study was conducted using in-depth interviews, drawing on the domains of a widely accepted patient-centred framework for health care access. Twenty-five adults with vision impairment were recruited from a community-based eye clinic in a suburb with high area-level deprivation. Interviews were audio-recorded, transcribed verbatim, coded, and analysed using thematic analysis. RESULTS: Twenty-five participants were interviewed, aged between 47 and 71 years, of whom 13 were female. The participants included 13 Pacific people, 6 Maori, 4 New Zealand Europeans and 2 people of other ethnicities. Thematic analysis revealed five themes describing accessing eye care from a community perspective. Two major themes related to barriers were identified, financial barriers and barriers due to location of services and transport. The facilitators of access were, the ability of individuals to identify available eye health services, the provision of appropriate eye health services, and the crucial role played by whanau (family) in supporting participants to seek eye health services. CONCLUSION: Cost is a major barrier to accessing eye health services in New Zealand. The barriers and facilitators expressed by this underserved community can inform efforts to improve eye health access in New Zealand through people-centred service designs.

Epithelium-on versus epithelium-off corneal collagen crosslinking for keratoconus: a systematic review and meta-analysis.

PURPOSE: Corneal collagen crosslinking (CXL) is the primary treatment for progressive keratoconus which has a significant impact on vision and quality of life. Our study aimed to compare the efficacy and safety of epithelium-on versus epithelium-off CXL to treat keratoconus. METHODS: We searched PubMed, Medline, Embase, Web of Science, and Scopus databases. We included studies that compared standard epithelium-off with epithelium-on CXL. The primary outcome measures were changes in corrected distance visual acuity (CDVA) and maximum keratometry (Kmax), and the secondary outcomes were uncorrected distance visual acuity (UDVA), central corneal thickness (CCT), and adverse events. A meta-analysis was performed on the primary and secondary outcomes based on the weighted mean differences between baseline to 12-month follow-up. RESULTS: The search retrieved 887 publications with 27 included in the systematic review. A total of 1622 eyes (1399 patients; age 25.51 ± 4.02 years) were included in comparisons of epithelium-off to epithelium-on CXL in keratoconus. Epithelium-off CXL treated 800 eyes and epithelium-on CXL for 822 eyes. At 12-month follow-up, CDVA and Kmax showed no significant difference between the epithelium-off and epithelium-on CXL. The secondary outcomes showed that UDVA was better in epithelium-off CXL (- 0.11D, 95% CI - 0.12, - 0.1; p < 0.001) and there was more thinning in CCT in epithelium-off CXL (- 3.23 µm, 95% CI - 4.64, - 1.81; p <0.001). CONCLUSION: Epithelium-off and epithelium-on CXL were both effective to treat progressive keratoconus. Further research is needed to compare the long-term outcomes and safety of both CXL protocols for adaptation into clinical practice.

Evaluation of ocular neuropathic pain.

AIM: To identify and assess the quality of current validated questionnaires that could be used to evaluate ocular neuropathic pain and its associated aetiologies. METHODS: A literature search was performed on MEDLINE, PubMed, EMBASE, PsycINFO and The Cochrane Library. Articles evaluating questionnaires for ocular neuropathic pain and its associated aetiologies were included. Data on psychometric properties, validity, and reliability of the questionnaires was extracted and analysed using a set of quality criteria. Clinical and demographical associations with ocular neuropathic pain were also reviewed. RESULTS: The search generated 1738 results with 61 publications meeting the inclusion criteria. The 61 publications covered 28 questionnaires including 3 ocular pain, 12 dry eye disease, 2 blepharitis, 2 refractive surgery, 3 contact lens wear, 3 Sjogren's Syndrome, and 3 that were non-disease-specific. Only 57 publications provided enough data on psychometric properties and validity of the questionnaire to be included for quality assessment. The Contact Lens Discomfort Index (CLDI) had the highest rated psychometric properties, whereas the English version of the Ocular Comfort Index (OCI) provided the most data on psychometric properties (9 out of 10 criteria). Most ocular pain and disease-specific questionnaires contained appropriate items to assess ocular pain in specific populations. However, non-disease-specific ophthalmic questionnaires demonstrated poor reliability and validity when evaluating ocular pain. CONCLUSION: Ocular pain questionnaires can potentially diagnose ocular neuropathic pain. Disease-specific questionnaires were limited to their target populations, and non-disease-specific ophthalmic questionnaires were unreliable. Further studies are required to determine the most appropriate questionnaire to evaluate ocular neuropathic pain.

Mental Health Impact of Keratoconus: A Systematic Review.

PURPOSE: The aim of this study was to investigate the impact of keratoconus on the mental health and emotional well-being of affected patients. METHODS: A literature search was conducted according to the PRISMA guidelines. Databases searched included MEDLINE, PubMed, EMBASE, Scopus, Web of Science, Cochrane, and PsycINFO. Articles were included if they were a primary study that investigated mental health or emotional quality-of-life outcomes in patients with keratoconus. RESULTS: Thirty-one articles met inclusion criteria of a total yield of 444. Most studies reported keratoconus to have a negative effect on mental health or emotional well-being. Worsening mental health scores correlated with lower visual acuity (VA) in the better eye, lower VA in the worse eye, increasing ocular asymmetry, and worsening disease severity. Mental health impacts were often reported to be disproportionate to that of the effects on VA. Over time mental health outcomes improved, suggesting stabilization of disease and patient acceptance. CONCLUSIONS: Patients with keratoconus may suffer detriments to mental health despite having relatively good VA. Understanding and acceptance of their disease may assist in assuaging mental health concerns. Further work may be needed to investigate whether benefit exists in routine mental health screening of patients with keratoconus.

Prevalence of refractive errors in Nepalese children and adults: a systematic review with meta-analysis.

CLINICAL RELEVANCE: Country-specific estimates of the prevalence of refractive errors are important to formulate national eye health policies for refractive care services. BACKGROUND: The purpose of this study was to systematically synthesise available literature and estimate the prevalence of refractive errors in the Nepalese population. METHODS: PubMed, Scopus, and Web of Science databases were systematically searched for articles on refractive errors and presbyopia published in English language until 27 September 2022. Population and school-based quantitative, cross-sectional prevalence studies and Rapid Assessment of Avoidable Blindness survey repository data were included. The quality of the included studies was assessed using the Newcastle Ottawa scale adapted for cross-sectional studies. Data extraction was performed with consensus among the reviewers. Meta-analysis of the prevalence was performed using the Random effects model to estimate the pooled proportions. RESULTS: A total of 38 studies with 101 701 participants were included: 18 studies in children (n = 31 596) and 20 in adults (n = 70 105). In children, the estimated pooled prevalence of overall refractive errors was 8.4% (95% CI: 4.8 to 12.9) with myopia, hypermetropia and astigmatism prevalent in 7.1% (95% CI: 3.7 to 11.4), 1.0% (95% CI: 0.7 to 1.3) and 2.2% (95% CI: 0.9 to 3.9), respectively. In adults, the prevalence of refractive errors, uncorrected refractive errors, and uncorrected presbyopia were 11.2% (95% CI: 8.0 to 14.9), 7.3% (95% CI: 5.4 to 9.5) and 78.9% (95% CI: 69.1 to 87.3), respectively. CONCLUSIONS: The pooled prevalence of refractive errors is relatively low while uncorrected refractive errors and presbyopia are high in Nepalese population suggesting a need for better access to refractive care services in the country. The paucity of quality evidence on prevalence of refractive errors, particularly in children, indicates a need for a well-designed population-based study to accurately estimate the current prevalence of refractive errors.

Efficacy and Safety of Standard Corneal Cross-Linking Procedures Performed With Short Versus Standard Riboflavin Induction: A Save Sight Keratoconus Registry Study.

PURPOSE: The objective of this study was to compare the effectiveness and safety of short versus standard riboflavin induction times in cross-linking (CXL) for keratoconus. METHODS: A retrospective comparative study was conducted with data from the Save Sight Keratoconus Registry. Inclusion criteria were epithelium-off technique, standard UVA CXL protocol (3 mW/cm 2 for 30 minutes), riboflavin induction for 15 minutes (short) or 30 minutes (standard), and 1 year of follow-up data after CXL. Outcome measures included changes in best-corrected visual acuity (BCVA), keratometry in the steepest meridian (K2), maximum keratometry (Kmax), thinnest pachymetry (TCT), and adverse events. Analysis was conducted using mixed-effects regression models adjusted for age, sex, visual acuity, keratometry, pachymetry, practice, and eye laterality. RESULTS: Two hundred eighty eyes (237 patients; mean, 27.3 ± 10.5 years old; 30% female) were included. The riboflavin induction time was short in 102 eyes (82 patients) and standard in 178 eyes (155 patients). The baseline characteristics (sex, mean age, BCVA, keratometry, and pachymetry [TCT]) were similar between the groups. At the 1-year follow-up visit, no statistically significant differences were observed in flattening in K2 and improvement in BCVA. Greater Kmax flattening [-1.5 diopters (D) vs. -0.5D, P = 0.031] and a greater proportion of >2% increase in TCT (23.5 vs. 11.3, P = 0.034) and haze (29 vs. 15, P = 0.005) were observed with short riboflavin induction. CONCLUSIONS: Short and standard riboflavin induction times achieved similar degrees of flattening in K2 and improvement in vision. Greater improvements in Kmax and TCT were seen with short riboflavin times; however, this group had higher rates of haze.

Five-year corneal cross-linking outcomes: A Save Sight Keratoconus Registry Study.

BACKGROUND: We aimed to determine the long-term outcomes of epithelium-off cross-linking (CXL) in keratoconus patients. METHODS: An observational registry study from 41 centres across 5 countries was carried out. Primary outcomes included the mean change in visual acuity (VA), Kmax, K2, and thinnest corneal thickness (TCT) at 1-5 years. Secondary outcomes included the percentage of eyes with worsening, stable and improving outcomes. RESULTS: There were 976 eyes of 794 patients with 1-year of complete follow-up, 501 eyes with 2-years, 355 with 3-years, 235 with 4-years and 162 with 5-years. There was a significant improvement in mean VA from baseline by 3.7 logMAR letters (p < 0.001) in year 1, and 6.9 (p < 0.001) in year 5. Mean Kmax decreased by 1.2 dioptres (D; p < 0.01) in year 1. During subsequent years the Kmax flattening appeared sustained but this was not statistically significant. K2 flattened significantly from baseline in year 1 and then remained stable. At 1 year, 4.1% patients were poor responders to CXL in terms of VA, losing ≥15 letters. The proportion of the poor responders remained unchanged: 4.9% at 5-years. The proportion of poor responders in terms of Kmax remained similar: 5.9% steepening by ≥2D at 1-year and 7.5% at 5-years. The proportion of K2 poor responders remained stable with 4.7% steepening by ≥2D at 1-year and 5.8% at 5-years. CONCLUSIONS: Cross-linking is effective at stabilising keratoconus up to 5 years in most patients. However, a small proportion of eyes failed to stabilise and had reduced vision.

Patient-Reported Outcomes in Keratoconus: A Save Sight Keratoconus Registry Study.

PURPOSE: The aim of this study was to evaluate the quality-of-life (QoL) status in keratoconus severity subgroups using the Keratoconus Outcomes Research Questionnaire (KORQ) and to determine the relationship between the QoL scores and the standard clinical variables. METHODS: A cross-sectional study was conducted using prospective, web-based Save Sight Keratoconus Registry data. Rasch analysis was conducted on the KORQ data using the Andrich Rating Scale Model. Comparative analysis included Welch t test and 1-way ANOVA. Associations between visual acuity, corneal curvature, and minimum corneal thickness with KORQ scores were evaluated with Pearson correlation and multiple regression adjusted for age and sex. RESULTS: The KORQ was completed by 542 patients with keratoconus (male, 67.7%; mean age, 31.6 years). Keratoconus severity, based on Kmax, was mild [<48 diopter (D)], moderate (48-55 D), and severe (>55 D) in 26.3%, 45.0%, and 28.7% of patients, respectively. Activity limitation (AL) and symptoms (SY) scales of the KORQ had robust psychometric properties including well-functioning response categories, unidimensionality, excellent measurement precision, and satisfactory fit statistics. In a group-wise analysis, the female patients had significantly lower AL and SY scores. Similarly, the severe keratoconus group had the worst AL and SY scores. Contact lens wearers had worse KORQ scores than the spectacles wearers. Overall, statistically significant but weak correlations between KORQ scores and visual acuity and corneal curvature (Kmax and K2) (Pearson r, 0.11-0.35) were observed. The correlations for SY were weaker than for AL scores. CONCLUSIONS: Female sex, contact lens wear, reduced visual acuity, and higher disease severity were associated with worse AL and SY scores in keratoconus. Although the correlations between clinical and QoL scores were statistically significant, the low magnitudes suggested a complex relationship between clinical parameters and patient-reported outcomes.

Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis.

PURPOSE: Keratoconus is a disorder that results in visual loss from increased corneal high-order aberrations and irregular astigmatism and reduces quality of life. The primary treatment for progressive keratoconus is crosslinking (CXL). Recently, it has been suggested that oxygen enhances the type II photodynamic reaction of CXL that is oxygen dependent. Our study investigated the effect of increased oxygen availability in epithelium-on CXL on visual acuity and corneal curvature. METHODS: We searched PubMed, EMBASE, Medline, Web of Science, and Scopus databases on November 3, 2021. We included studies that reported increased oxygen availability during CXL in patients with keratoconus published within the last 10 years. A meta-analysis on the primary outcomes, maximum keratometry, and corrected distance visual acuity, was conducted. RESULTS: The search yielded 108 publications which were screened and assessed for eligibility. Six studies were included in the systematic review and 5 studies were included in our meta-analysis of the outcomes of increased oxygen availability in accelerated CXL. The meta-analysis on data after 6 months of follow-up found a significant decrease in mean maximum keratometry of 1.2 diopter (95% confidence interval: 0.2-2.3; P =0.02) and an improvement in mean corrected distance visual acuity by 0.08 logMAR (95% confidence interval, 0.02-0.13; P =0.01). There were no serious adverse events reported. CONCLUSIONS: Increasing oxygen during epithelium-on CXL improved visual acuity and produced corneal flattening without any serious adverse events in patients with keratoconus. The demarcation line depth was significantly higher with oxygen compared to the control group. Further data are required with a control group and long-term follow-up across a range of CXL protocols for implementation into standard clinical practice.

Evaluation of corneal topography, pachymetry and higher order aberrations for detecting subclinical keratoconus.

PURPOSE: To compare corneal topography, pachymetry and higher order aberrations in keratoconic and normal eyes; to investigate their association in keratoconic eyes; and to determine their diagnostic ability for detecting subclinical keratoconus in a Nepalese population. METHODS: Ninety-six eyes of 48 keratoconus patients and 50 normal eyes of 50 control subjects were included in this study. The eyes of keratoconus patients were classified into four different study groups: subclinical, stage 1, stage 2 and advanced stage keratoconus. In each eye, corneal topography, pachymetry and corneal aberrometry indices were measured using a Sirius corneal tomographer. The study parameters of keratoconic eyes were compared with normal eyes, and the possible association of corneal aberrometry with topography and pachymetry indices was investigated. The area under curve (AUC) of receiver operating characteristic (ROC) curves along with optimal cutoff values with best sensitivity and specificity were also determined for each index to detect subclinical keratoconus. RESULTS: All the indices except average keratometry measurements (Kavg and mmavg ) and spherical aberration (SA) were found to be significantly different in subclinical keratoconus compared to the control group (p < 0.05). In keratoconic eyes, all corneal aberrations were significantly correlated with the topography and pachymetry indices (range of ρ: -0.25 to 0.96; all p < 0.05) except for trefoil and minimum corneal thickness (Thkmin ). All the indices except Kavg , mmavg and SA showed excellent diagnostic ability (AUC > 0.90) in detecting subclinical keratoconus. The cutoff values proposed for the asymmetry index of the corneal back surface (SIb ), Strehl ratio of point spread function (PSF), coma and Baiocchi-Calossi-Versaci index of corneal back surface (BCVb ) each showed excellent sensitivity (100%) and specificity (≥97%). CONCLUSIONS: Corneal higher order aberrations were found to be significantly elevated in subclinical keratoconus compared to healthy controls. SIb , PSF, coma and BCVb were identified as the most powerful Sirius indices for the detection of subclinical keratoconus.

Quality of life impact of eye diseases: a Save Sight Registries study.

BACKGROUND: The objectives of this study were to evaluate the quality-of-life (QoL) impact of eye diseases (keratoconus; neovascular age-related macular degeneration, AMD; retinal vein occlusion, RVO; and diabetic macular edema, DME) using the Impact of Vision Impairment (IVI) questionnaire, and to determine the relationship between the IVI scores and visual acuity. METHODS: This cross-sectional, multicentre, real-world study utilised the prospective, web-based Save Sight Registries. The IVI was completed by 1557 patients: 307 with keratoconus, 1049 with AMD, 148 with RVO and 53 with DME. Statistical analysis included Rasch analysis, Welch t-test, one-way ANOVA, Tukey's test, Pearson correlation, and multiple regression. RESULTS: The IVI scales (Overall; Visual Function, VF; Emotional, EM) had robust psychometric properties. The keratoconus patients had the worst Overall (adjusted mean: 48.2 vs. DME 58.8, RVO 64.6, AMD 67.6 units), VF (47.7 vs. DME 59.4, RVO 65.9, AMD 68.9 units) and EM (50.8 vs. DME 63.1, RVO 69.2, AMD 71.8 units) scores (all p < 0.05). The IVI scales scores weakly correlated with better and worse eye visual acuity (Pearson's r 0.24-0.39, all p < 0.05). The correlations were similar in the better eye (Overall 0.35, VF 0.39, EM 0.24) and the worse eye (Overall 0.31, VF 0.33, EM 0.25) visual acuity. Correlations with visual acuity were stronger for VF than for the EM scores. CONCLUSIONS: The IVI was a psychometrically robust QoL questionnaire. Keratoconus patients had worse IVI scores than patients with retinal diseases. The low strength of correlations between visual acuity and QoL scores, although statistically significant, suggested that a complex relationship exists.