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Purpose: To compare the characteristics of the quantitative contrast sensitivity function (qCSF) in eyes with early keratoconus (Early-KC) and normal control (NC) eyes and investigate the associated factors. Design: A cross-sectional study. Methods: This study included 43 eyes of 43 patients with Early-KC (including subclinical keratoconus [SKC] and forme fruste keratoconus [FFKC]) and 77 NC eyes of 77 participants with corrected distance visual acuity (CDVA) all ≥ 20/20. Contrast sensitivity (CS) was assessed using the qCSF tests. Subgroup analysis was performed according to keratoconus type(SKC and FFKC) and astigmatism(cylindrical refraction >-1.0D or ≤-1.0D). Results: Sex ratio, spherical refraction, and spherical equivalent (SE) varied significantly between the two groups (all P < 0.01). The area under log CSF (AULCSF), CSF Acuity, and CS at low (1.0 and 1.5 cycles per degree [cpd]) and high (12.0 and 18.0 cpd) spatial frequencies decreased significantly in the Early-KC group than that in the NC group (all P < 0.05). The subgroup analysis revealed a similar decrease in the SKC group (all P < 0.05). AULCSF, CSF Acuity, and CS at high spatial frequencies of patients with cylindrical refraction ≤-1.0D in the Early-KC group decreased significantly (all P < 0.05) than those in the NC group. The index of vertical asymmetry and index of height decentration correlated negatively with CS at 1.5 cpd (r= -0.321 and -0.306; both P < 0.05). Conclusions: CS decreased significantly at low and high spatial frequencies in Early-KC, though with normal CDVA. The qCSF test can sensitively reflect visual performance in early keratoconus. [ABSTRACT FROM AUTHOR]

Background: To investigate the agreement between a mobile applet‐based visual acuity (VA) self‐test program and the conventional VA tests. Methods: This consecutive case series study included 121 children and adults (242 eyes). Patients were classified into three groups according to age (children, adolescents, and adults). They underwent uncorrected distance visual acuity (UDVA) testing, distance visual acuity with available spectacle correction (DVA with ASC) testing at 2.5‐m distance, uncorrected near visual acuity (UNVA) testing, and near visual acuity with available spectacle correction (NVA with ASC) testing at a 0.4‐m distance using a mobile applet‐based VA self‐test program and conventional VA tests in two eyes. Results: Correlations among UDVA, DVA with ASC, UNVA, and NVA with ASC between the two methods were significant in all subjects (all p < 0.001). The intraclass correlation coefficient were 0.960, 0.845, 0.960, and 0.669, respectively (all p < 0.001). The proportions of bias outside the 95% confidence interval limit of agreements were 6.20%, 4.82%, 7.08%, and 6.10%, respectively. There were significant differences in NVA with ASC between the two methods (p < 0.05) in the adolescent group, but no differences in measured parameters were found among children and adult groups. Conclusions: There is good agreement between the mobile applet‐based VA self‐test program and the conventional VA tests. The VA self‐test has good practical value especially in the current pandemic, allowing self‐screening of visual acuity, myopia control, and remote management of visual impairment in ocular morbidity. [ABSTRACT FROM AUTHOR]

Purpose: To compare bilateral differences in corneal biomechanics between keratoconus and normal eyes. Methods: In this case-control study, 346 eyes of 173 patients (aged 22.1 ± 6.1 years) with keratoconus (KC group) and 378 eyes of 189 patients (aged 26.7 ± 5.6 years) with ametropia (control group) were enrolled. Corneal tomography and biomechanical properties were examined using Pentacam HR and Corvis ST, respectively. The corneal biomechanical parameters were compared between eyes with forme fruste keratoconus (FFKC) and normal eyes. Bilateral differences in corneal biomechanical parameters were compared between the KC and control groups. Receiver operating characteristic (ROC) analysis was used to assess discriminative efficacies. Results: The areas under the ROC curves (AUROCs) of stiffness parameter at the first applanation (SP-A1) and Tomographic and Biomechanical Index (TBI) for identifying FFKC were 0.641 and 0.694, respectively. The bilateral differential values of major corneal biomechanical parameters were significantly increased in the KC group (all p < 0.05), except for the Corvis Biomechanical Index (CBI). The AUROCs of the bilateral differential values of the deformation amplitude ratio at 2 mm (ΔDAR2), Integrated Radius (ΔIR), SP-A1 (ΔSP-A1), and the maximum inverse concave radius (ΔMax ICR) for discriminating keratoconus were 0.889, 0.884, 0.826, and 0.805, respectively. The Logistic Regression Model-1 (comprising of ΔDAR2, ΔIR, and age) and the Logistic Regression Model-2 (comprising of ΔIR, ΔARTh, ΔBAD-D, and age) had AUROCs of 0.922 and 0.998, respectively, for discriminating keratoconus. Conclusion: The bilateral asymmetry of corneal biomechanics was significantly increased in keratoconus compared with normal eyes, which may be helpful for the early detection of keratoconus., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Xian, Zhao, Sun, Zhang, Ding, Liu, Li, Ding, Jiang, Zhou and Shen.)