Optometry and Vision Science最新文献

Significance: Central corneal epithelial thinning associated with midperipheral epithelial thickening has been reported as the main factor contributing to the effectiveness of orthokeratology (ortho-k) in myopia control. Yet, the cellular mechanism governing the regional change in refractive power remains elusive.

Purpose: This study aimed to evaluate the correlation between the regional change in corneal epithelial thickness and cell density in ortho-k wearers.

Methods: A new human prototype of a polarization-dependent optical coherence microscope was developed to enable noncontact and noninvasive in vivo imaging of corneal epithelial cells in ortho-k wearers with and without their ortho-k lens. The epithelial thickness and cell density were evaluated at the central and midperipheral corneal locations in four ortho-k wearers and four spectacle wearers serving as controls.

Results: Polarization-dependent optical coherence microscope achieved in vivo volumetric imaging of all epithelial cell types in ortho-k wearers with and without their lens over a field of view of 0.5 × 0.5 mm 2 with an isotropic resolution of ~2.2 mm. The central epithelial thinning and midperipheral epithelial thickening were consistent across all ortho-k wearers. However, the inconsistency in their regional epithelial cell density highlighted a great variability in individual response to ortho-k treatment. There was no strong correlation between epithelial thickness and cell density, especially at the midperipheral cornea, in ortho-k participants.

Conclusions: This study constitutes our first step toward uncovering the cellular mechanism underlying the effectiveness of ortho-k in myopia control. Future studies will focus on the longitudinal evaluation of epithelial cells before and during ortho-k treatment to identify factors governing individual response to ortho-k treatment and ultimately inform the dynamics of epithelial cells taking place during the ortho-k treatment.

Purpose: We aimed to develop a paradigm that can efficiently characterize motion percepts in people with low vision and compare their responses with well-known misperceptions made by people with typical vision when targets are hard to see.

Methods: We recruited a small cohort of individuals with reduced acuity and contrast sensitivity (n = 5) as well as a comparison cohort with typical vision (n = 5) to complete a psychophysical study. Study participants were asked to judge the motion direction of a tilted rhombus that was either high or low contrast. In a series of trials, the rhombus oscillated vertically, horizontally, or diagonally. Participants indicated the perceived motion direction using a number wheel with 12 possible directions, and statistical tests were used to examine response biases.

Results: All participants with typical vision showed systematic misperceptions well predicted by a Bayesian inference model. Specifically, their perception of vertical or horizontal motion was biased toward directions orthogonal to the long axis of the rhombus. They had larger biases for hard-to-see (low contrast) stimuli. Two participants with low vision had a similar bias, but with no difference between high- and low-contrast stimuli. The other participants with low vision were unbiased in their percepts or biased in the opposite direction.

Conclusions: Our results suggest that some people with low vision may misperceive motion in a systematic way similar to people with typical vision. However, we observed large individual differences. Future work will aim to uncover reasons for such differences and identify aspects of vision that predict susceptibility.

Significance: Clinicians and researchers would benefit from being able to predict the onset of myopia for an individual child. This report provides a model for calculating the probability of myopia onset, year-by-year and cumulatively, based on results from the largest, most ethnically diverse study of myopia onset in the United States.

Purpose: This study aimed to model the probability of the onset of myopia in previously nonmyopic school-aged children.

Methods: Children aged 6 years to less than 14 years of age at baseline participating in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study who were nonmyopic and less hyperopic than +3.00 D (spherical equivalent) were followed up for 1 to 7 years through eighth grade. Annual measurements included cycloplegic autorefraction, keratometry, ultrasound axial dimensions, and parental report of children's near work and time spent in outdoor and/or sports activities. The onset of myopia was defined as the first visit with at least -0.75 D of myopia in each principal meridian. The predictive model was built using discrete time survival analysis and evaluated with C statistics.

Results: The model of the probability of the onset of myopia included cycloplegic spherical equivalent refractive error, the horizontal/vertical component of astigmatism (J0), age, sex, and race/ethnicity. Onset of myopia was more likely with lower amounts of hyperopia and less positive/more negative values of J0. Younger Asian American females had the highest eventual probability of onset, whereas older White males had the lowest. Model performance increased with older baseline age, with C statistics ranging from 0.83 at 6 years of age to 0.92 at 13 years.

Conclusions: The probability of the onset of myopia can be estimated for children in the major racial/ethnic groups within the United States on a year-by-year and cumulative basis up to age 14 years based on a simple set of refractive error and demographic variables.

Significance: This multicenter study assessed clinical and psychological aspects of infantile nystagmus syndrome (INS) focusing on its management and nonsurgical treatment.

Purpose: This study aimed to assess clinical features, management, relationship life, and psychological impact in a group of patients with nystagmus onset in pediatric age.

Methods: This observational study included patients diagnosed with INS referred to two Italian centers from January 1, 2017, to December 31, 2020. Ophthalmologic and orthoptic features and impact of visual function on quality of life, according to nystagmus-specific nystagmus quality of life questionnaire, were analyzed within the overall sample and in any of INS subgroups.

Results: Forty-three patients were included; 65.1% of them had idiopathic INS (IINS), and 34.9% had INS associated with ocular diseases (INSOD). The median age was 15.4 years (interquartile range [IQR], 10.4 to 17.3 years), significantly different between groups (median, 15.8 years among those with IINS vs. 12.3 years among those with INSOD; p<0.001). In the INSOD subgroup, strabismus was significantly more prevalent (93.3 vs. 57.1%; p=0.017). Binocular distance best-corrected visual acuity in primary position was significantly higher in the IINS subsample (p<0.001). Such behavior was further confirmed at anomalous head position evaluation (p<0.001). At near best-corrected visual acuity assessment, differences between groups were more remarkable in primary position (p<0.001) than in anomalous head position. Contrast sensitivity showed significantly higher values in the IINS subgroup (p<0.001). The nystagmus quality of life questionnaire disclosed a significantly lower score in IINS as compared with INSOD (median total score, 90.5 [IQR, 84 to 97] vs. 94 [IQR, 83.0 to 96.5]; p<0.001).

Conclusions: The IINS group showed significantly better ophthalmologic and orthoptic outcomes than the INSOD group. The psychological and quality-of-life impact was instead significantly greater in the IINS group. To the best of our knowledge, this is the first multicenter study investigating the clinical features of IIN and comparing the two main subgroups, IINS and INSOD.