Mohammed Alhazmi

Background: Dry eye disease (DED) and refractive errors are increasingly prevalent among young adults, particularly in populations with prolonged digital device use. However, the relationship between refractive error, axial length (AL), and dry eye parameters remains incompletely understood. Methods: A cross-sectional observational study was conducted among 114 young Saudi adults attending the optometry clinic of King Saud University. Participants underwent comprehensive ocular examination including refractive assessment, AL measurement, Ocular Surface Disease Index (OSDI), non-invasive tear breakup time (NI-TBUT) and tear breakup time (TBUT). Refractive error was classified into hyperopia and myopia, with further stratification by severity. Continuous variables are presented as mean ± standard deviation (SD), while categorical variables are summarized as frequencies and percentages. One-way ANOVA was performed among refractive error groups, whereas the Kruskal–Wallis H test was used for dry eye severity. Pearson’s correlation, Spearman’s correlation, Bonferroni-adjusted post-hoc analysis, and linear regression analysis were performed, keeping the p-value < 0.05. The study got IRB approval and adhered to the tenets of the declaration of Helsinki. Results: The mean age of participants was 23.95 ± 3.73 years, with 64.9% females. Mean daily screen-time was 9.40 ± 2.93 h. Axial length demonstrated a weak positive correlation with OSDI scores; however, it did not reach statistical significance (r = 0.174, p = 0.065). Similarly, AL was not significantly correlated with TBUT (r = −0.134, p = 0.157) or NI-TBUT (r = −0.147, p = 0.120). In contrast, screen time showed significant correlations with the OSDI scores (r = 0.650, p < 0.001), TBUT (r = −0.585, p < 0.001), and NI-TBUT (r = −0.509, p < 0.001). Dry eye severity differed significantly across refractive error groups (Kruskal–Wallis H = 18.762, p = 0.002), showing higher refractive error associated with greater dry eye severity. Multivariable regression analyses demonstrated that greater screen time was significantly associated with higher OSDI scores and shorter TBUT and NI-TBUT, whereas spherical equivalent (SE) was not independently associated with any of these dry eye outcomes after adjusting for demographic variables. Additionally, greater screen time was significantly associated with composite dry eye severity (Spearman’s ρ = 0.639, p < 0.001). Conclusions: Prolonged digital screen exposure showed the most consistent association with greater dry eye severity, whereas refractive error and axial length were not independently associated with dry eye outcomes after adjustment for screen time and demographic factors. Although unadjusted differences exist across certain refractive subgroups, behavioral factors such as screen time may contribute to dry eyes. These findings support comprehensive dry eye evaluation in individuals with refractive error and prolonged digital device use.

Purpose: To evaluate the impact of a myopia control (MC) spectacle lens incorporating peripheral defocus on functional visual parameters compared to conventional single vision (SV) lenses. Methods: Thirty-nine young adults (age 21.1 ± 1.3 years; spherical equivalent −2.85 ± 2.8 D) participated in this single-session, within-subject crossover design. Distance and near LogMAR VA were assessed centrally and at 22° nasal and temporal off-axis. Distance contrast sensitivity (CS) was measured across five spatial frequencies (1.5–18 cpd) and the Area Under the Log CS Function (AULCSF) calculated. Retinal sensitivity was evaluated using automated static perimetry. Dynamic visual performance was assessed using a standardized video game platform. Outcomes were compared using repeated measures ANOVA or Wilcoxon signed-rank tests. Results: Central VA was comparable between lens types. MC lenses significantly reduced off-axis distance VA (nasal: 0.35 ± 0.15 LogMAR; temporal: 0.20 ± 0.14 LogMAR; both p < 0.001) and near VA (nasal: 0.72 ± 0.25 LogMAR; temporal: 0.34 ± 0.2 LogMAR; both p < 0.001). Off-axis AULCSF was significantly reduced with MC lenses (nasal: 12.07 ± 5.06 vs. 26.37 ± 5.00 units; temporal: 13.00 ± 6.93 vs. 27.14 ± 4.64 units; both p < 0.001), while central AULCSF remained similar between lens types (SV: 27.87 ± 5.04 vs. MC: 27.15 ± 5.02 units; p = 0.277). No significant differences were found for visual field indices (all p > 0.05). Video game accuracy was comparable between lenses, but task completion time was slower with MC lenses (20.71 ± 10.08 vs. 18.39 ± 6.65 s; p = 0.012). Conclusions: MC spectacle lenses preserve central VA, CS, and visual field sensitivity but induce significant off-axis VA and off-axis CS reductions. Dynamic visuomotor accuracy is maintained, though task completion speed is modestly reduced. These functional trade-offs should be considered when prescribing MC lenses.

Traditional color vision tests lack the sensitivity to detect subtle differences in individuals with normal color vision. The Konan ColorDx Cone Contrast Threshold (CCT) HD test allows the quantitative measurement of color discrimination thresholds for each cone type. This cross-sectional study established normative values for L-, M-, and S-cone contrast sensitivities and evaluated the effects of age and sex on color discrimination thresholds. Participants aged 15–79 years with normal color vision were included (n = 216; 55% female). CCTs were measured monocularly using the Konan ColorDx CCT HD test under standardized conditions, and the influences of age and sex on L-, M-, and S-cone sensitivities were evaluated. In all groups, L-cone sensitivity was the highest, followed by the M- and S-cone sensitivities. Overall contrast sensitivity was significantly higher in females than in males (mean difference = −0.041), especially for adolescents and young adults (20–24 years). Young adults outperformed middle-aged and older adults, with age-related decline most pronounced for S-cone sensitivity in those over 60. The right and left eye sensitivities did not differ. This study provides age- and sex-stratified normative data for the Konan Color Dx CCT HD test, supporting its use for clinical and occupational assessments.

This study aimed to evaluate the static and dynamic pupil changes, and light sensitivity following a single dose of low-dose atropine at concentrations of 0.01%, 0.025%, and 0.05% over a 24 h period. Healthy young adults (20–22 years; n = 25) participated in this randomized, double-blind study. Each participant received one of three atropine concentrations in a masked fashion. Baseline mesopic and dynamic pupil sizes were measured at various post-instillation intervals (5 min, 30 min, 1 h, 2 h, 4 h, and 24 h). A minimum 48 h washout period was observed between treatments. Subjective light sensitivity was assessed using the Visual Light Sensitivity Questionnaire (VLSQ-8) at 24 h. All atropine concentrations caused significant pupil dilation (p < 0.001), with the 0.05% concentration producing the greatest dilation (peak mesopic size: 7.4 mm, p < 0.001) and the slowest recovery at 24 h (6.4 mm, p < 0.001). The dynamic pupil constriction range was most restricted with 0.05% (1.7 mm, p < 0.05), compared to 0.025% (2.2 mm) and 0.01% (2.6 mm). Subjective symptoms, including light sensitivity and glare, followed a dose-dependent pattern (p < 0.05). In 60% participants, 0.05% caused the most symptoms, while in 70% participants, 0.01% caused the least. Despite significant pupil dilation, the pupil center coordinates did not shift significantly along the horizontal or vertical axes (p > 0.05). Low-dose atropine induced dose-dependent pupil dilation and light sensitivity; 0.05% atropine caused the most pronounced effects. These findings underscore the importance of tailoring the atropine dosage to balance its efficacy and tolerability. Further studies are needed to explore the long-term impact of repeated dosing on pupillary behavior and subjective symptoms.

Background: Individuals with congenital color vision defects (CVDs) are at greater risk of misidentifying colors, necessitating an investigation into their ability to distinguish colors accurately. This study aimed to assess how individuals with CVDs perceive the colors in the Worth four-dot (W4D) and duochrome tests. It also explored whether individuals with CVDs require more detailed instructions from optometrists and eye care providers during these tests. Method: Thirty-two participants with congenital CVDs were recruited for this study. Participants with ocular diseases were excluded based on a brief questionnaire. The participants underwent a W4D test to determine the colors of four circles and the duochrome test without using filters. Result: All the participants correctly identified the W4D colors, except for five participants (15.62%). Furthermore, among all the participants, two (one with deuteranopia and one with protanopia) failed to identify the colors correctly in the duochrome test (6.25%). Conclusions: The findings suggest that in the context of optometric assessment, it could be essential for optometrists to incorporate a preliminary inquiry into a patient’s ability to identify colors prior to performing diagnostic tests such as the W4D or duochrome tests. Incorrect responses from patients with CVDs might mislead optometrists regarding the proper outcomes of the test.

PurposeTo investigate the immediate impact of nicotine consumption on Retinal Nerve Fiber Layer (RNFL) thickness in healthy young individuals, comparing nicotine gum and electronic cigarette (vaping) as delivery methods.Materials and MethodsTwenty participants underwent RNFL measurements at baseline, 30, and 60 minutes after consuming 4 mg of nicotine, based on product labeling and specifications. Measurements were obtained using optical coherence tomography (OCT) (Topcon 3D OCT-1 Maestro System). Nicotine was delivered through either nicotine gum or vaping.ResultsBoth nicotine gum and vaping led to a statistically significant increase in RNFL thickness, with no significant difference between the two methods. The analysis revealed that area, time, and visit factors significantly affected RNFL scores. Stratification by smoking type (tobacco, vaping, dual) demonstrated significant effects for area, time, and visit factors, with an interaction effect among these factors.ConclusionsThe findings highlight the acute impact of nicotine intake on RNFL thickness in young healthy smokers. Researchers and clinicians should account for recent nicotine exposure when evaluating RNFL thickness, particularly within the first hour post-smoking. The observed significant effects warrant further research, especially in older or health-compromised populations, to improve clinical protocols and diagnostic evaluations across different demographics.

Purpose To explore whether differences in choroidal thickness arise from nicotine consumption in healthy young individuals, specifically comparing the effects of nicotine gum to electronic cigarette (vaping), while maintaining a consistent 4 mg nicotine dosage. Methods In a randomized double-blinded prospective cross-sectional study, 20 healthy participants (mean age ± standard deviation: 23 ± 2.36 years) were randomly assigned to either the nicotine gum or vaping group. Choroidal thickness (ChT) measurements were conducted using optical coherence tomography (OCT) (Topcon 3D OCT-1 Maestro System) at baseline, 30, and 60 min after ingesting 4 mg of nicotine, with ChT measurements taken from five different horizontal areas. Results Neither the nicotine delivery method (gum or vaping) demonstrated a statistically significant impact on ChT mean scores among subjects in the five measured areas at baseline, 30, and 60 min (p > 0.05). However, significant differences were observed in ChT mean scores within subjects across the five areas (F (1.83, 72) = 36.43, p < 0.001), regardless of other study factors such as group, time, and visit (p > 0.05). A statistically significant interaction was identified between the factors of area and time concerning participants' ChT mean scores when stratified by the type of smoking (tobacco, vaping, and dual) (p = 0.003). Conclusion The results of this study revealed that nicotine, up to particular concentration of 4 mg, does not have a statistically significant vasoconstrictive effect on choroidal thickness, regardless of the delivery method, within the examined group. These findings offer valuable insights into the relationship between nicotine intake and choroidal dynamics in young adults.

Purpose: To investigate the variations in choroidal thinning between emmetropic and myopic subjects after caffeine intake. Methods: Forty-five healthy participants (age mean ± standard deviation [SD]: 20.75 ± 1.6 years) recruited in a prospective cross-sectional study. They were divided into three groups, based on refractive error status, emmetropes (spherical equivalent [SE] -0.25 to +0.25D), myopes (SE ≥-0.50D to ˂-6.00D), and high myopes (SE ≥-6.00D). The participants underwent choroidal thickness [ChT] measurements using optical coherence tomography [OCT] (Topcon 3D OCT-1 Maestro System) at baseline, 20, 40, and 60 minutes after consuming 200 mg of caffeine. The measurements of ChT were taken from five different areas horizontally. Results: Compared to baseline measurement, the ChT significantly decreased after 200 mg caffeine intake in all conditions ( P < 0.001). There was a statistically significant difference in ChT at baseline between the refractive groups ( χ ² (2)=6.548, P = 0.038) as the high myope group showed lesser horizontal ChT within Nasal at (1 mm) area compared to the myope group ( P = 0.032), however, no other significant differences in mean scores of horizontal ChT at baseline were found. The thinning in ChT in the high myope group was lesser compared to both emmetrope and myope groups; however, it was not statistically significant ( P > 0.05). Conclusion: The results of this study suggest that the reduction in ChT due to caffeine consumption is not significantly affected by the refractive status of the eye. Thus, it is safe to hypothesize that the vascular part of the choroid behaves identically to vasoconstrictive in both emmetropic and myopic eyes. The choroidal thinning found in myopic and high myopic eyes and/or the reduced choroidal vascularity index were not apparent in this study. Therefore, further longitudinal studies recruiting greater numbers of participants, including myopes and high myopes, and measuring both vascular and stromal layers to investigate such variations are warranted.