PURPOSE:To evaluate the diagnostic accuracy of objective tests including Visual Evoked Potentials (VEP), pupillometry, and eye-tracking technologies in detecting ocular malingering among individuals suspected of fabricating visual impairments for secondary gain. METHODS:Following PRISMA guidelines, PubMed, Web of Science, Scopus, EMBASE, and Cochrane Library were searched until June 2025. Studies evaluating objective diagnostic methods for detecting ocular malingering that reported diagnostic accuracy metrics were included. Two reviewers performed data extraction and quality assessment using QUADAS-2. RESULTS:Ten studies from 1993 to 2017 with 20 to 222 subjects were included. Approximately half of the studies employed experimentally simulated malingering paradigms, while the remainder involved clinically suspected cases. VEP was the most frequently evaluated modality and showed high sensitivity across studies, although specificity varied. Pattern-reversal VEPs showed effectiveness in adults and military conscripts, while step VEPs demonstrated 100% specificity in paediatric cases. Pupillometry and specialised colour vision tests achieved 80-94% sensitivity and specificity rates. Most studies showed low bias risk in index test and reference standard domains. These findings suggest potential utility of objective tools as adjuncts in clinical and medico-legal settings. CONCLUSION:Objective diagnostic measures demonstrate promising utility as adjunctive tools for detecting ocular malingering and may support clinical decision making by providing reproducible assessments that bypass voluntary patient control. However, heterogeneity in study designs limits generalisability. Future research should standardise protocols and validate findings across diverse populations.
PURPOSE:To evaluate the association between Active Vision Therapy (AVT) combined with occlusion and occlusion-only therapy in task-based saccadic and pursuit visuomotor performance and visual outcomes in children with anisometropic amblyopia. METHODS:Forty children (median age=9years, IQR=7-11) with persistent anisometropic amblyopia after six weeks of spectacle adaptation were alternately assigned to AVT-occlusion (n = 23) or occlusion-only (n = 17). BCVA, stereopsis, contrast sensitivity, and task-based saccadic and smooth pursuit performance were measured at baseline, three weeks, six weeks, and three months. AVT included structured monocular and binocular exercises using Vision Training System 4 and Cheiroscope, while occlusion involved daily patching of the fellow eye. Repeated-measures ANOVA and Friedman tests evaluated changes over time, partial Spearman correlations adjusted for group examined associations between oculomotor and visual improvements. RESULTS:Both groups improved in BCVA, and task-based saccadic and smooth pursuit performance (p < 0.05) in the AVT-occlusion group. Significant time × therapy interactions were found for BCVA, task-based saccadic and smooth pursuit performance, and contrast sensitivity (p ≤ 0.03). At three months, AVT-occlusion outperformed occlusion-only in BCVA (-0.13 logMAR, p = 0.01), task-based saccadic response time (-0.78 ms equivalent, P < 0.001) and task-based smooth pursuit performance (4.68%, p = 0.03), and contrast sensitivity (0.06 log-units, p = 0.005). Greater gain in task-based saccadic (ρ=-0.43, p = 0.006) and smooth pursuit (ρ=-0.53, p = 0.001) performance correlated with BCVA improvement; faster saccadic response performance (ρ=0.35, p = 0.026) correlated with better stereopsis. CONCLUSIONS:AVT with occlusion was associated with greater improvements in functional visuomotor task performance and visual outcomes in children with anisometropic amblyopia, supporting its role as a function-oriented adjunct to conventional therapy.
PURPOSE:Short-term visually induced axial eye shortening and choroidal thickening are of interest since they may be linked to reduced myopia development. We studied whether axial eye shortening, induced by imposing positive defocus, varies throughout the day, and whether emmetropes and myopes differ in their responses. METHODS:Twenty young adults (10 emmetropes, 10 myopes) completed a daytime protocol conducted between 10:00 am and 3:00 pm, consisting of repeated 30- minute sessions of movie watching while the right eye was myopically defocused by a trial lens, imposing approximately +3D of myopic defocus at the viewing distance used. Each session was started and was followed by a washout period of 15 min. Axial length was measured in both eyes using the Lenstar LS900 biometer immediately before and after each session at five time points. RESULTS:Emmetropic eyes showed significant axial length shortening in response to imposed myopic defocus in the morning (10 am: -10.1 ± 7.8 µm, p = 0.0028, 11 am: -9.8 ± 7.0 µm, p = 0.0017) and again in the afternoon (3 pm: -11.2 ± 5.2 µm, p = 0.0001). No significant responses were observed at 1:00 pm and 2:00 pm. Different from emmetropes, myopic eyes did not exhibit significant axial length changes at any time point. CONCLUSIONS:Emmetropic eyes exhibited time-of-day-dependent variability in short-term axial length responses to myopic defocus, with stronger responses in the morning and afternoon but no responses around midday. The mechanisms underlying choroidal thickening appear to be modulated over the day. Myopic eyes showed minimal or no responses to positive defocus.
BACKGROUND:Optical coherence tomography (OCT) provides high-resolution structural measurements of the retina, choroid, and optic nerve. Pediatric normative data, particularly in European populations, remain scarce. This study aimed to describe OCT-derived macular, choroidal, and peripapillary parameters in Portuguese children and adolescents (6-18 years) and evaluate associations with refractive status. METHODS:Cross-sectional study including 605 children (127 myopes, 263 emmetropes, 215 hyperopes). OCT parameters included subfoveal choroidal thickness (SFCT), foveal and macular retinal thickness, inner limiting membrane to retinal pigment epithelium (ILM-RPE) volumes, and peripapillary retinal nerve fiber layer (RNFL) metrics. Refractive status, axial length, and visual acuity (LogMAR) were recorded. Data were analyzed using ANOVA or Kruskal-Wallis tests, and multivariate linear regression analyses were performed adjusting for age, sex, axial length, and optic disc area. RESULTS:SFCT was significantly thinner in myopic eyes (298.55 ± 58.52 µm) compared with emmetropes (316.58 ± 51.46 µm; p = 0.001), while hyperopes showed intermediate values (298.70 ± 52.46 µm). Foveal retinal thickness did not differ significantly among groups (p = 0.727). Peripapillary RNFL thickness was reduced in myopes compared with emmetropes in multiple sectors (p < 0.001). Macular ILM-RPE volume and area were slightly lower in myopes (p < 0.05). Axial length was correlated with SFCT (r≈-0.18) and RNFL thickness (r≈-0.30). Multivariate analyses confirmed that SFCT remained independently associated with refractive group after adjustment, whereas RNFL differences were largely explained by axial length and optic disc area. CONCLUSION:This study provides the most comprehensive multi-parameter OCT normative dataset in Portuguese schoolchildren to date, including macular, choroidal, and peripapillary parameters in the largest Portuguese pediatric cohort (n = 605), highlighting refractive error-related structural differences. These data provide population-level normative reference values that may inform clinical and research applications in Portuguese pediatric populations, pending validation in independent cohorts.
Background To evaluate risk behaviors for infectious keratitis among contact lens (CL) wearers in Switzerland, focusing on survey-based, observational subgroup analyses by contact lens type. Methods This investigator-initiated, cross-sectional, survey-based, observational, multi-center study was conducted across five eye care institutions in Switzerland. Between August 2023 and August 2024, we interviewed participants wearing CLs using a structured questionnaire. We assigned four subgroups, which included daily disposable soft contact lenses (SCL), reusable SCL, rigid corneal contact lenses (RCL), and rigid scleral contact lenses (ScCL). The survey collected data on demographics, CL type and indication, self-assessed CL knowledge, and risk behaviors related to infectious keratitis. We classified risk behaviors into three main categories, including hand hygiene, wearing behavior, and exposure to water or saliva. Results 156 participants were included in the final analysis. Regarding the subgroup allocation, 38 of 156 (24.4%) wore daily disposable SCLs, 48 (30.8%) reusable SCLs, 40 (25.6%) RCLs, and 30 (19.2%) ScCLs. Overall, participants wearing rigid CLs felt better informed about CL care and demonstrated fewer risk behaviors than SCL users. However, risk behaviors were observed across all subgroups, including applying or removing lenses with potentially contaminated hands, extended CL wear, sleeping with CLs, and exposure to water or saliva. Conclusion This study revealed variations in hygiene practices, wearing behavior, exposure to water or saliva, and risk perception across different CL types. Nevertheless, risk factors for infectious keratitis were present among all subgroups, underscoring the need for lens-specific patient education under professional supervision to improve compliance and mitigate complications.
Purpose: To assess the value of optical coherence tomography angiography (OCTA) peripapillary retinal vascularization in differentiating papilledema from pseudopapilledema. Methods: A cross-sectional study, prospective recruitment patients diagnosed with papilledema and pseudopapilledema between January 2021 and December 2022. Papilledema: mild-moderate acute optic disc edema due to increased intracranial pressure. Pseudopapilledema: optic nerve drusen and other causes confirmed by multi-modal imaging techniques. Mean and sectoral peripapillary flux index and perfusion density were measured using commercial software. Diagnostic performance was analyzed using the area under the receiver operating characteristic curve (AUC). Results: Sixty-five patients (mean age, 36.5 years; 63.1% women) were included: 14 with papilledema (28 eyes; mean age 37.1 years, 9 women) and 51 with pseudopapilledema (95 eyes, mean age 36.4 years, 32 women), with no significant differences in age or gender. Significant differences were found for flux index in the nasal sector (p = 0.034). Mean perfusion density was significantly higher for papilledema (44.377%) than for pseudopapilledema (42.460%) (p = 0.036), as was perfusion in the nasal sector (p = 0.005). Mean vascular flux index had an AUC of 0.683 (95% CI, 0.518-0.848), with 76.9% sensitivity and 58.8% specificity, with a cut-off of 0.461. Mean perfusion had an AUC of 0.665 (95% CI 0.492-0.838), with 53.8% sensitivity and 76.5% specificity, with a cutoff of 44.25%. Conclusions: OCTA displayed higher peripapillary flux index and perfusion in papilledema than pseudopapilledema in the nasal region. These parameters showed moderate diagnostic accuracy and may serve as adjunctive tools in the differential diagnosis of optic disc swelling.
Aim: To synthesise evidence on retinal, choroidal, and microvascular alterations detected by OCT/OCTA in amblyopic eyes and their modulation by conventional therapy. Methodology: MEDLINE, Embase, Scopus, and Cochrane CENTRAL were searched without language restrictions, along with manual screening of reference lists and relevant trial registries. Eligible studies included cross-sectional or longitudinal human studies comparing OCT/OCTA parameters in amblyopic eyes with fellow or agematched control eyes. Two reviewers independently performed study screening, data extraction, and quality assessment. Due to substantial clinical and methodological heterogeneity among the included studies, a qualitative narrative synthesis was conducted to summarize findings across studies. Results were stratified according to amblyopia subtype and treatment status. Results: Thirty studies were included. Most studies reported increased RNFLT and central macular thickness in anisometropic amblyopia, whereas findings in strabismic amblyopia were inconsistent. OCTA studies commonly demonstrated reduced superficial capillary plexus density in untreated amblyopic eyes. Longitudinal studies showed modest therapy-related structural changes, with possible earlier microvascular improvement. Methodological heterogeneity and incomplete axial-length correction were common limitations across studies. Conclusions: OCT/OCTA reveal consistent retinal thickening and superficial vascular reduction in anisometropic amblyopia, while other types show minimal changes. Standardized, axial length-corrected longitudinal studies are needed to clarify causality and prognostic significance.
Purpose Age-related macular degeneration (AMD) is a common ocular condition leading to reduced central visual function and increased dependency on the peripheral field of view for all visual tasks. This study aims to assess the effect of optical errors on peripheral vision in dry form AMD. Methods High contrast resolution acuity and contrast sensitivity were measured in the 20° nasal visual field of fourteen subjects with advanced or early dry AMD. The measurements were performed through an adaptive optics vision simulator to simulate average phakic as well as pseudophakic peripheral optical errors. Results Overall, inducing population average phakic optical errors resulted in better peripheral visual function than average pseudophakic optical errors for all measured subjects, both in high contrast resolution acuity and contrast sensitivity. Specifically, the mean differences between phakic and pseudophakic conditions were 0.16 logMAR in resolution acuity and 0.43 in logarithmic contrast sensitivity. These changes are larger than the results of studies on younger subjects with healthy vision. Conclusion The study thereby concludes that reducing peripheral optical errors can improve peripheral vision, although further work is needed to determine how this translates to everyday visual performance. Interestingly, the improvement appears to be larger for AMD patients compared to healthy eyes.
Background: To compare the effect of corneal rigid and scleral contact lenses (CRCL & SCL) on binocular vision and accommodative function in keratoconus (KCN) patients. Methods: In this prospective non-randomized comparative interventional study, patients aged 20 to 40 years with a definitive diagnosis of KCN were participated. Only patients with the best-corrected visual acuity (BCVA) of 0.40 LogMAR or better were included. A comprehensive examination including assessment of BCVA, refractive error, and stereopsis were performed. Furthermore, all participants underwent the complementary binocular vision and accommodation testing. All examinations were performed by spectacle and then repeated after contact lens fitting in both groups. Results: In total, 31 patients were recruited (12 in the CRCL group and 19 in the SCL group). Both groups demonstrated significant improvements in BCVA after lens fitting in both eyes, with the SCL group showing an average gain of approximately 1-3 lines. Additionally, a higher proportion of patients in the SCL group achieved central stereopsis (<100 sec/arc) following lens fitting (p = 0.011). Conclusions: While both SCL and CRCL contributed to improved visual acuity in patients with KCN compared with spectacle, SCL exhibited more advantages over CRCL, particularly in enhancing stereopsis and fusional vergence performance.
Objectives This study aimed to evaluate amblyopic participants with myopic anisometropia who, despite not being initially diagnosed with strabismus, failed to improve their visual acuity (VA) after treatment. The hypothesis is that these individuals present with microtropia (MT) and sensory adaptations. Since they appear orthotropic on the unilateral cover test, the hypothesis was tested through an objective evaluation of fixation, the presence of eccentric fixation (EF) would indicate that these eyes are monocularly deviated. Methods Fourteen participants (16.07 ± 10.56 years) were recruited from the Vision Clinic at the University of Murcia. They were myopic, amblyopic, anisometropic, and initially classified as non-strabismic, with no improvement following treatment. They underwent refractive, motor, sensory, eye health and fixation assessments using visuoscopy. Results A slight tendency towards esophoria was observed at distance (1.07Δ ± 2.67Δ) and near (2.50Δ ± 6.26Δ). Refraction in amblyopic eyes was 3D more myopic than in non-amblyopic eyes, showing a strong correlation (r = 0.91, p < 0.0001). A non-significant relationship was found between the degree of anisometropia and VA in the amblyopic eye (r = -0.27, p = 0.3944), as well as between anisometropia and stereopsis (Spearman rs = 0.22, p = 0.439). Of the 14 amblyopic eyes evaluated, 10 presented with EF (indicating strabismus), 2 had unstable fixation, 1 could not be evaluated, and 1 presented central fixation. Conclusion The majority of the participants evaluated (71.4%) exhibited MT and EF. While this association is well-documented in hyperopic anisometropia, it has not been previously characterized in myopic anisometropia.
PURPOSE:Handheld photorefractors are increasingly used in paediatric populations, where patient cooperation and examination time are often limited. Given this widespread use, it is essential to characterise potential sources of measurement error. This study aimed to investigate the dependence between interpupillary distance (IPD) measurements and measurement distance (MD) when using Plusoptix A12R. METHODS:Variability in interpupillary distance (IPD) measurements with the Plusoptix were observed during a paediatric vision screening programme (n = 67). A theoretical model predicting a linear IPD - MD relationship was developed, including a correction factor. The model was validated under controlled conditions (n = 3) using a bench testing. Then, a pilot study (n = 8) was carried out under habitual clinical conditions to assess the applicability of the correction factor. IPD measurements obtained with the Plusoptix before and after correction were compared with those obtained using a pupilometer. Agreement between methods was assessed using Bland-Altman analysis and Cohen's effect size. RESULTS:In 42% of children, IPD measurements were relatively stable (SD ≤ 1 mm), whereas 9% showed fluctuations exceeding 4 mm. Bench testing data confirmed a strong linear dependence of IPD on MD (slope = 0.99), with larger IPD values obtained at shorter MDs. The pilot study showed that applying the proposed correction factor reduced IPD variability and improved agreement with pupilometer measurements. CONCLUSIONS:IPD measurements obtained with the Plusoptix A12R are affected by MD, introducing a systematic and predictable error. The application of a correction factor effectively compensates for this effect improving its clinical reliability.
Purpose: To evaluate the influence of professional guidance on a novel subjective refraction method combining a tunable liquid lens (TLL) and a Stokes lens, and to determine whether clinician involvement affects refractive accuracy, visual outcomes, or testing time compared with a participant-driven approach. Methods: Sixty-six participants (18-44 years old) underwent monocular subjective refraction in one randomly selected eye under two conditions: a professional-guided refraction (ORx) performed by an experienced optometrist, and a do-it-yourself (DIY) condition where participants completed the procedure independently. Both methods used the same optical system for continuous spherical and astigmatic adjustment. Three consecutive measurements were taken under repeatability conditions. Refractive components (M, J(0), J(45)), visual acuity, and measurement time were compared using Passing-Bablok regression and non-parametric tests. Results: A strong agreement was found between both methods, with slopes including the value 1 within the 95% confidence intervals. Intercepts for the spherical equivalent (M) and time did not include zero, indicating a small systematic bias: M values were slightly more positive and measurement time longer in the ORx condition. This effect was more evident in hyperopic and near-emmetropic eyes. No statistically significant differences were observed between methods (p > 0.05). Both techniques showed a learning effect with reduced time across repetitions. Conclusion: DIY subjective refraction achieved comparable accuracy and visual outcomes to professional-guided procedures. While clinician supervision improved consistency and accommodative control, the DIY approach demonstrated feasibility as a complementary and accessible option for hybrid or remote refraction applications.
Purpose: This study aimed to evaluate the relationship between the DEM test and reading speed, its diagnostic accuracy (sensitivity and specificity), and its usefulness as a screening tool for reading difficulties. We also examined how reading speed is associated with other optometric measures. Methods: A retrospective study was conducted involving children aged 7 and 8 years. Reading speed was assessed using the PROLEC test. The optometric evaluation included visual acuity, stereopsis, accommodative facility, near point of convergence, cover test, retinoscopy, and eye movements assessed with the DEM test. The standard DEM parameters were analyzed. In addition, given the aim of the study, a new outcome variable was introduced: the total time, calculated as the sum of the vertical and adjusted horizontal times. Results: A total of 48 children participated in the study. When both age groups were analyzed together, all DEM parameters showed significant correlations with reading speed (vertical time, r=-0.52,p <0.01; adjusted horizontal time, r=-0.63,p <0.01; ratio, r=-0.48,p < 0.01; and total time, r=-0.58,p < 0.01). The best sensitivity-specificity combination for detecting below-age PROLEC scores was obtained using the adjusted horizontal time (whole sample: 80 %/45 %). AUC ranged from 0.59 (ratio) to 0.79 (total time). A significant association was also found between reading speed and accommodative function (p = 0.02). Conclusion: The application of the DEM test for detecting reading difficulties should be approached with caution. Although DEM results show a correlation with reading speed and demonstrate high sensitivity, specificity remains low regardless of the DEM measure used.
PURPOSE:This study aimed to evaluate the efficacy of Systane COMPLETE Preservative-Free in improving symptoms of occasional dryness, particularly towards the end of the day. METHODS:A multicentric longitudinal prospective study was conducted. Participants were required to have an Ocular Surface Disease Index (OSDI) score between 13 and 32 (mild-to-moderate symptoms of dryness). Subjects used Systane COMPLETE Preservative-Free four times a day (upon waking, at midday, in the afternoon, and two hours before bedtime) for one month. Weekly questionnaires were administered, and a review was conducted at the beginning and end of the study. The Wilcoxon signed-rank test was used to compare OSDI, DEQ-5, Efron scale scores, and corneal staining using the Oxford scale. Correlations between environmental variables and symptom scores were also analyzed. RESULTS:This sample included 19 men and 67 women with a mean age of 42.6 ± 13.2. Statistically significant improvements were observed in both questionnaires (OSDI and DEQ-5) across all visits (p < 0.01) reducing the score to less than half, particularly with a decrease in symptoms at the final visit after artificial tear use (DEQ-5). The DEQ-5 questionnaire score at the initial visit correlates (Spearman's Rho) with limbal hyperemia (ρ = 0.24; p = 0.02), and conjunctival staining (ρ = 0.28; p < 0.01). The OSDI questionnaire score correlates with conjunctival staining (ρ = 0.38; p = 0.03). Moreover, the DEQ-5 questionnaire score showed correlations with several environmental factors (ρ = 0.23-0.33; p < 0.04). CONCLUSIONS:Systane COMPLETE Preservative-Free has proven effective in improving moderate ocular dryness symptoms, as measured by the OSDI questionnaire, as well as end-of-day dryness, as assessed by the DEQ-5.
PURPOSE:To evaluate the impact of keratoconus on visual quality and quality of life among Polish patients by integrating subjective assessments using the Keratoconus Outcomes Research Questionnaire (KORQ) with objective clinical measurements. METHODS:A total of 100 patients (80% men, 20% women; median age: 39 years) with clinically diagnosed keratoconus completed the locally validated Polish version of the KORQ, including two subscales: Activity Limitation (18 items) and Symptoms (9 items). Objective data collected included best-corrected visual acuity (BCVA), corneal topography, pachymetry, and higher-order aberrations (HOA). Statistical analyses included biweight midcorrelations and robust linear regression models adjusted for age and gender. RESULTS:The mean Activity Limitation score was 51.53 (SD = 17.19) and the Symptoms score was 55.60 (SD = 16.14), indicating moderate functional impairment and symptom burden. The most challenging activities were night driving (mean = 2.06), seeing small distant objects (mean = 2.09), and coping with poor lighting (mean = 2.05). The most bothersome symptoms were distorted vision (mean = 1.84), sensitivity to smoke (mean = 2.05), and dusty environments (mean = 2.01). Higher-order aberrations, especially in the worse-seeing eye, showed the strongest associations with KORQ scores across both subscales (e.g., for Symptom subscale: HOA: β = 2.84; p = 0.004; vertical coma: β = 5.83; p = 0.019), while BCVA in the better-seeing eye was significantly associated with both lower symptom burden (β = -9.83; p = 0.047) and functional limitation (β = -12.13; p = 0.042). Traditional structural parameters, such as Kmax and corneal thickness, showed no significant predictive value. CONCLUSIONS:Keratoconus significantly impairs visual functioning and causes a high symptom burden among Polish patients. Best-corrected visual acuity and higher-order aberrations, especially in the worse-seeing eye, are the strongest predictors of reduced vision-related quality of life. These findings emphasize the need to focus clinical management on improving optical quality, rather than solely correcting structural corneal features.
PURPOSE:To characterize longitudinal astigmatism changes and their interaction with spherical equivalent (SE) progression in Chinese school-age children. METHODS:We retrospectively reviewed medical records of patients with long-term follow-up data from 2008 to 2022. Patients aged 6-10 years at initial visit and 16 years at last assessment, with a cylinder refraction of 0.75 D or greater, were selected. Astigmatism was analyzed in clinical notation and vector notation (J0, J45). Factors related to annual changes in astigmatism and SE and their interaction were analyzed. RESULTS:A total of 2946 patients (mean age 8.72 ± 1.21 years at initial visit) were followed up for 7.40 ± 1.23 years. In low astigmatism (≤1.50 D), cylinder power increased by 0.018 D/y with age, whereas in high astigmatism (≥3.00 D), it decreased by 0.048 D/y (p < 0.001). Oblique astigmatism (J45) increased by 0.008 D/y, and with-the-rule (WTR) astigmatism (J0) decreased by 0.005 D/y (p < 0.001). A more negative baseline SE at initial visit was associated with greater increase in astigmatism magnitude (β = -0.004, p < 0.001), and higher baseline astigmatism magnitude was associated with less SE progression (β = 0.047, p < 0.001). CONCLUSION:In this large longitudinal cohort of Chinese school-age children, astigmatism progression exhibited a baseline-dependent pattern. Myopia was associated with a modest acceleration of astigmatism progression, whereas higher astigmatism conferred a slight protective effect against myopic shift. This study demonstrates these refractive interactions, though their clinical applicability is limited by small effect sizes.
PURPOSE:To evaluate the in vitro measurement of central thickness (CT) in soft contact lenses using two commercial optical coherence tomography (OCT) systems by analyzing their repeatability and agreement. METHODS:A randomized, controlled, investigator-masked trial was conducted using 120 soft contact lenses made from eight different materials. Three examiners measured the CT of the soft contact lenses using two commercial OCT systems with a spherical support marked for correct lens centration. One system was a swept-source OCT, and the other a spectral-domain OCT. Intra- and inter-examiner repeatability were assessed. Comparisons between the OCT systems and the electronic thickness gauge, considered the gold standard, were analyzed. Agreement between the two OCT systems was evaluated using Bland-Altman plots. RESULTS:Both OCT systems showed a 95% confidence interval for intra-examiner repeatability of <10.0 µm for most materials. Inter-examiner repeatability was worse than intra-examiner repeatability, exceeding 10.0 µm in some materials. The mean differences between the OCT devices and the electronic thickness gauge were <10 µm. Swept-source OCT provided slightly lower CT values than spectral-domain OCT, although most differences were within ± 10 µm. CONCLUSION:Both OCT systems demonstrate good repeatability and strong agreement with the electronic thickness gauge for measuring the central thickness of soft contact lenses, and can be used interchangeably. These findings support their use as a viable alternative in lens development, manufacturing, and quality control.
PURPOSE:To determine whether iris pigmentation introduces a measurable bias in corneal densitometry (CD) values obtained via Scheimpflug imaging, and to develop an objective metric for iris color quantification. METHODS:This observational study included 91 eyes from 47 healthy adults. CD was assessed as mean pixel intensity (MPI) from 25 Scheimpflug images per eye. Brightness artefacts from the iris were quantified using automated image processing. Iris color was objectively characterized from slit-lamp photographs using an objective single-value metric (IrisColor) derived from normalized CIELAB components. Associations among CD, iris brightness, and iris pigmentation were evaluated using Pearson correlation and linear mixed-effects models (LMMs). RESULTS:CD correlated positively with iris brightness artefacts (r = 0.47, β = 1.49, p < 0.001), which in turn showed a strong negative correlation with IrisColor (r = -0.83, β = -1.11, p < 0.001). Lighter-colored irises (lower IrisColor values) exhibited statistically significantly higher CD values equivalent to a 6.6% relative overestimation. Groupwise comparisons confirmed that iris pigmentation significantly influences both CD and overall image brightness. CONCLUSION:Iris pigmentation induces a measurable bias in Scheimpflug-based CD estimates, primarily through increased brightness artefacts in light-colored eyes. The proposed IrisColor metric enables objective, continuous classification of iris color and could support future corrections for pigmentation-induced bias in CD-based diagnostics.
Purpose: To assess the repeatability and validity of computerized distance visual acuity (VA) charts from Optonet Vision Unit (OVU) using a Continuing Professional Development (CPD) programme which recreates real-life scenario conditions. Methods: This is a multicentric study with 481 participants aged from 7 to 88 years. Distance VA was assessed by OVU with five different computerized VA charts, according to Bailey and Lovie's principles (Sloan, British, Numbers, Landolt C and Broken Rings). Two consecutive measurements (TCM) and two measurements (Test re-test (TRT)) were evaluated (95% limits of agreement (LOA), ICC 95%). Results: In all VA charts, the mean difference between measurements was near 0.00 logMAR and there was an excellent correlation between TCM (ICC ≥0.968, 95% LOA of ±0.071 logMAR) and TRT (ICC ≥0.957, 95% LOA of ±0.09 logMAR). Pairwise comparison between VA charts showed a statistical difference between tests, with a minimum mean difference of 0.003 logMAR (95% CI, -0.010 to 0.004) between Landolt C and Broken rings; and a maximum mean difference of 0.071 logMAR between Sloan letters and Numbers (95% CI, -0.075 to -0.067). Conclusions: The reliability and reproducibility of OVU software for distance VA measurement is promising for eye care practitioner consultation highlighting the possibility of expanding the use of OVU for both clinic and research. The use of online CPD programs is useful to improve statistical and research understanding is an innovative, hands-on approach that helps in bridging the gap between clinical practice and research.
