SubFoveal Choroidal Imaging in High Myopic Nepalese Cohort.

Purpose: Evidence suggests that choroid is thinner in myopes as compared to nonmyopes. However, choroidal thickness varies with the refractive error, age, axial length, and ethnicity. The purpose of this study was to determine the subfoveal choroidal thickness (SFCT) in high myopic Nepalese subjects and to investigate its association with the mean spherical equivalent refractive error (MSE), axial length, and age. Methods: Ninety-two eyes of 92 high myopic subjects (MSE ≤ -6 diopters) and 83 eyes of 83 emmetropic subjects (MSE: 0.00 Diopters) were included in the study. SFCT was assessed using spectral domain optical coherence tomography, and the axial length was measured using partial coherence interferometry. SFCT was measured manually using the inbuilt tool within the imaging software. Results: SFCT in the high myopic subjects was significantly thinner (mean ± SD: 224.17 ± 68.91 µm) as compared to the emmetropic subjects (353.24 ± 65.63 µm) (mean difference, 127.76 ± 130.80 µm, and p < 0.001). In high myopic subjects, there was a significant negative correlation of choroidal thickness with the axial length (rho = -0.75; p < 0.001) and MSE (rho = -0.404; p < 0.01). Regression analysis demonstrated a decrease of choroidal thickness by 40.32 µm (p < 0.001) for every 1 millimeter increase in the axial length and by 11.65 µm (p < 0.001) for every 1 diopter increase in the MSE. Conclusion: High myopic Nepalese subjects had significantly thinner choroid as compared to emmetropes. The MSE and axial length were inversely correlated with the SFCT. Age had no effect on SFCT in this study. These findings may have implications in interpreting choroidal thickness values in clinical and epidemiological studies in myopes, especially in the south Asian population.

Flash VEP in clinically stable pre-term and full-term infants.

PURPOSE: Pre-term infants are at risk of abnormal visual development that can range from subtle to severe. The aim of this study was to compare flash VEPs in clinically stable pre-term and full-term infants at 6 months of age. METHODS: Twenty-five pre-term and 25 full-term infants underwent flash VEP testing at the age of 6 months. Monocular VEPs were recorded using flash goggles on a RETIscan system under normal sleeping conditions. Amplitude and peak time responses of the P2 component in the two eyes were averaged and compared between the two groups. Multiple regression analyses were performed to assess the relationship of the P2 responses with birth weight (BW) and gestational age (GA). RESULTS: At 6 months corrected age, pre-term infants had significantly delayed P2 peak times than full-term infants (mean difference: 10.88 [95% CI 4.00-17.76] ms, p = 0.005). Pre-term infants also showed significantly reduced P2 amplitudes as compared to full-term infants (mean difference: 2.36 [0.83-3.89] µV, p = 0.003). Although the regression model with GA and BW as fixed factors explained 20% of the variance in the P2 peak time (F2,47 = 5.98, p = .0045), only GA showed a significant negative relationship (ß = -2.66, p = .003). Neither GA (ß = 0.21, p = .28) nor BW (ß = 0.001, p = .32) showed any relationship with P2 amplitude. CONCLUSIONS: Our results demonstrate that, compared with full-term infants, clinically stable pre-term infants exhibit abnormal flash VEPs, with a delay in P2 peak time and a reduction in P2 amplitude. These findings support a potential dysfunction of the visual pathway in clinically stable pre-term infants as compared to full-term infants.

Sub-Foveal Choroidal Thickness In Healthy Nepalese Population.

PURPOSE: This study was conducted primarily to measure sub-foveal choroidal thickness (SFCT) in healthy Nepalese population. Also, the correlation of SFCT with age, inter-eye difference of SFCT, inter-gender variation and inter-ethnic variation of SFCT was observed. MATERIALS AND METHODS: A cross-sectional, hospital based study in 162 participants (324 eyes) of six ethnic groups (Brahmin, Chhetri, Newar, Tamang, Muslim, and Gurung) was conducted. The mean age of participants was 37.37 ± 15.02 years. All the participants underwent SFCT measurement using Spectral Domain Optical Coherence Tomography (Spectralis HRA+OCT, Heidelberg Engineering, Germany) with the help of in-built caliber. Age, inter-gender, inter-eye and inter-ethnic differences in SFCT were recorded and analyzed. RESULTS: The average SFCT of right eye (RE) and left eye (LE) was 307.98 ± 74.64 µm and 312.63 ± 76.90 µm respectively, with average SFCT of 310.31 ± 75.70 µm for both eyes. SFCT of only the RE was selected for further calculation due to insignificant inter-eye difference of SFCT (p = 0.128). There was a significant negative correlation of SFCT with age (r = -0.705, p = 0.01). A regression analysis showed thinning of SFCT by 3.50 ± 0.278 µm per year. In another context, SFCT of male and female was 305.49 ± 79.72 µm and 313.55 ± 70.76 µm respectively. However, there was no significant inter-gender difference (p = 0.51). Similarly, inter-ethnic variations of SFCT was also statistically non -significant (p = 0.74). CONCLUSION: SFCT was negatively correlated with the age of participants, implying a decrease in choroidal thickness (CT) with an increase in age. Age can be considered as an important factor in the measurement of SFCT. Gender and ethnic groups did not have a significant role in the measurement and comparison of SFCT.

Constructing Item Banks for Measuring Quality of Life in Refractive Error.

SIGNIFICANCE: Existing patient-reported outcome instruments in refractive error are paper-based questionnaires. They are not comprehensive and psychometrically robust. This study has identified the content of the refractive error-specific item banks that aim to provide comprehensive and scientific measurement of refractive error-specific quality of life. PURPOSE: The purpose of this study was to identify minimally representative, optimally informative, and efficient sets of items for measuring quality of life in people with refractive error. METHODS: First, items were identified from existing patient-reported outcome instruments. Second, items were developed from qualitative studies with people with refractive error (48 and 101 in-depth interviews in Australia and Nepal, respectively). Third, classification and selection of items were done based on a set of systematic criteria using an iterative process of binning and winnowing. The resulting items underwent cognitive testing with people with refractive error in Australia and in Nepal. Each step was guided by an expert panel consensus. RESULTS: We retrieved 792 items from the existing patient-reported outcome instruments. From the interviews conducted in Australia, a total of 2367 comments were coded into 807 initial items. Similarly, from the interviews conducted in Nepal, 3477 comments were coded into 914 initial items. After binning and winnowing, followed by cognitive testing, a final set of items comprising 337 items for the Item-pool (Australia) and 308 items for the Item-pool (Nepal), both spanning 12 domains, was obtained. Forty-seven percent of items were common across the two item pools. In the Item-pool (Nepal), 65% items were common for corrected and uncorrected refractive error. CONCLUSIONS: We identified the content of two different sets of item banks to comprehensively measure the impact of refractive error on quality of life for people in Australia and Nepal, which may be applicable to high-income country settings and low- and middle-income country settings, respectively. Future work aims to develop computer-adaptive testing system to administer the item banks, resulting in useful measurement tools for researchers, clinicians, and policy planners.