Purpose: To examine the regional distribution of choroidal thickness (ChT) and the diurnal variation in ChT and axial length (AL) over a wide range of myopic refractive error. Methods: ChT was measured in thirty-four healthy young adults (age mean ± SD: 25.2 ± 2.8, range: 18– 35 years) using spectral-domain optical coherence tomography and AL using an IOL-Master 500. Participants were divided into three refractive groups: emmetropes, myopes, and high myopes. We evaluated ChT in macular (foveal, parafovea, and perifovea) and peripheral regions (6-mm from the foveal pit) in four quadrants (superior, temporal, inferior, and nasal). To assess the diurnal variation, three measurement sessions of ChT and AL were taken at 8 AM, 12 PM, 4 PM. Results: ChT thins progressively towards the periphery. Superior and nasal quadrants exhibited the thickest (277 ± 73 μm) and thinnest (218 ± 89 μm) choroid, respectively. Higher myopic eyes showed an overall thinner choroid (237 ± 48 μm) compared to myopic eyes (264 ± 78 μm) (P < 0.05). Higher myopes exhibited a significant choroidal thinning in all quadrants except in the temporal quadrant (all p < 0.05). Both ChT and AL underwent a significant diurnal variation (p < 0.05). The ChT and AL diurnal variation amplitudes in higher myopes were significantly reduced (ChT: 14.6 ± 11, AL: 14.5 ± 13 μm), compared to those in emmetropes (ChT: 21.4 ± 15, AL: 21.3 ± 8.5 μm) and myopes (ChT: 19 ± 17, AL: 19 ± 9.7 μm). Diurnal variation amplitude in ChT did not differ significantly across quadrants and choroidal eccentricity regions (p > 0.05). Conclusion: ChT distribution varies based on quadrant and eccentricity; superior choroid exhibited the thickest, and nasal showed the thinnest choroid. Higher myopes experience a reduced diurnal variation in ChT and AL.

Purpose: To investigate topographical and within-day changes in the choroidal vascularity index and its association with choroidal thickness parameters (total, luminal, and stromal thickness) among young adults. Methods: Choroidal thickness and vascularity index were measured in 28 healthy young adults (age mean ± standard deviation [SD]: 25 ± 3.0) using spectral-domain optical coherence tomography. Participants were divided into three refractive groups: emmetropes, myopes, and high myopes. Choroidal parameters were evaluated in the macular and peripheral regions in the superior and inferior regions at two time points during the day; in the morning (at 7 am) and in the afternoon (at 1 pm). Results: All investigated choroidal thickness parameters showed a significant topographical variation across the vertical meridian, between the foveal (270 ± 89 μm, 170 ± 45 μm, and 111 ± 47 μm, respectively) and peripheral (246 ± 68 μm, 160 ± 39 μm, 86 ± 36 μm, respectively). The superior choroid was thicker in all thickness parameters compared to the inferior choroid. A significant increase in the vascularity percentage was seen from the fovea (61.8 ± 7%) toward the periphery (66.4 ± 7%). Thinner choroidal parameters were associated with high myopia, whereas an increase in the vascularity index was observed in high myopes. Significant within-day changes were observed in all choroidal thickness parameters, which were slightly reduced in the afternoon. The choroidal vascularity index (CVI) increased from 61.3 ± 5.3% in the morning and 63.2 ± 5.8% in the afternoon. High myopes exhibited reduced within-day amplitude in stromal thickness. Conclusion: All parameters showed significant regional variations. Myopia is associated with greater thinning in stromal thickness rather than vascular thickness. Only high myopes experienced reduced within-day change amplitudes in stromal choroidal thickness that was more predominant in the foveal and parafoveal regions.

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.

AIM: To investigate the impact of multifocal gas permeable contact lens (MFGPCL) in various add power and distance/near area allocation on short-term changes of choroidal thickness (ChT), axial length (AL), and retinal defocus profile in young adults. METHODS: Seventeen young adults (2 males and 15 females; age 23.17±4.48y) were randomly assigned to wear two designs binocularly with a one-week washout period in between. Total of four MFGPCL designs were assessed. All designs were distance-center that varied in two add power (+1.50 and 3.00 D) and/or two distance zone (DZ) diameters (1.50 and 3.00 mm; design A: DZ 1.5/add 3.0, B: DZ 1.5/add 1.5, C: DZ 3.0/add 3.0, D: DZ 3.0/add 1.5). ChT, AL, and peripheral refraction data were collected on each subject at baseline, on days 1 and 7 of MFGPCL daily wear. ChT was assessed in four quadrants using a spectral-domain optical coherence tomography. RESULTS: AL was shortened by -26±44 µm with lens C, -18±27 µm with lens D, -13±29 µm with lens A, and -8±30 µm with lens B (all P<0.05). A significant overall increase in ChT was observed with all 4 designs (lens A: +6±6 µm, B: +3±7 µm, C: +8±7 µm, and D: +8±7 µm). Temporal and superior choroid exhibited more choroidal thickening associated with MFGPCL. All designs induced significant relative peripheral myopia (RPM) beyond the central 20o across the horizontal meridian in both nasal and temporal fields (P<0.05). CONCLUSION: MFGPCLs show a significant influence on ChT and AL, which are associated with significant increase in RPM after short-term wear. The reliability and feasibility of quantifying short-term changes in ChT support its use as a promising marker for the long-term efficacy of myopia-controlling treatments.

Purpose. Smoking has a negative effect on health and ocular tear film. The purpose of the current study is to investigate the correlation between the TearLab and I-Pen osmolarity scores in smokers and compare them with those of non-smoking healthy males. Methods. Thirty male smokers (25.3±2.2 years) participated in the study. An age-matched (22.9±2.0 years) control group of non-smoking healthy males (N=30) was also recruited for comparison purposes. The ocular surface disease index (OSDI) was completed first, followed by the TearLab and I-Pen osmolarity measurements. Results. The median TearLab osmolarity score was lower (P<0.001) than that obtained using the I-Pen in both the study and the control groups. The OSDI scores and osmolality measurements were higher (P<0.001) in smokers than in the control subjects. In the smoker group, there were moderate correlations between the OSDI scores and the measurements obtained using the TearLab (Spearmans correlation coefficient, r=0.463; P=0.010) and I-Pen (r=0.449; P=0.013) systems. In addition, there was a strong correlation between the osmolarity scores obtained from the TearLab and I-Pen systems in smokers (r=0.911; P<0.001). Conclusion. The I-Pen scores in smokers were significantly higher than those obtained using TearLab. The TearLab scores showed small variations compared with those obtained using I-Pen. A strong correlation was found between the TearLab and I-Pen scores in smokers. The osmolarity TearLab and I-Pen scores were significantly higher in smokers compared with normal eye subjects.

Purpose: Due to the COVID-19 pandemic, wearing a face mask has become an essential measure to reduce the rate of virus spreading. The aim of the study was to assess the effect of wearing a surgical face mask for a short period on the tear film parameters in subjects with a high body mass index (BMI).Methods: Twenty-five females with a high BMI (31.4 ± 5.5 kg/m²) aged 18–35 years (22.7 ± 4.6 years) participated in the study. In addition, a control group consisting of 25 females (23.0 ± 6.7 years) with a high BMI (29.9 ± 4.1 kg/m²) participated in the study in which no mask was worn. The standardized patient evaluation of eye dryness (SPEED) questionnaire was completed first, followed by the phenol red thread (PRT) and tear ferning (TF) tests, before wearing the face mask. The subjects wore the face mask for 1 hour, and the measurements were performed again immediately after its removal. For the control group, the measurements were performed twice with one hour gap.Results: Significant (Wilcoxon test, p < 0.05) differences were found between the SPEED scores (p = 0.035) and the PRT measurement (p = 0.042), before and after wearing the surgical face mask. The PRT scores have improved after wearing the surgical face mask, while the dry eye symptoms detected by the SPEED questionnaire have increased. On the other hand, no significant (Wilcoxon test, p = 0.201) differences were found between the TF grades before and after wearing a surgical face mask. For the control group, no significant (Wilcoxon test, p > 0.05) differences were found between the two scores from the SPEED questionnaire and the PRT, and TF tests.Conclusions: Wearing a surgical face mask for a short duration leads to a change in volume and quality of tears as well as dry eye symptoms in women with a high BMI.