METHODS: Permission was obtained to translate the English versions into Malay and subsequently validate them, and to validate the existing Chinese versions. The translated questionnaires were taken for pilot testing. Validation was carried out for the face/content and discriminant validity. Reliability was assessed for test-retest and internal consistency using Cronbach's alpha and intraclass correlation coefficient respectively. The responsiveness was calculated via effect size and standardized response mean.

RESULTS: Ten patients were recruited for the pilot testing. The English and Chinese versions had "substantial" or "almost perfect" agreement as measured by weighted Kappa. 284 participants (139 patients with stress urinary incontinence and 145 healthy volunteers) were included in the subsequent phases. The ICIQ-UI SF and ICIQ-LUTSqol had good discriminant validity. The ICIQ-UI SF had moderate internal consistency although the ICIQ-LUTSqol had good internal consistency. Both questionnaires had high test-retest reliability. Responsiveness was established with a moderate to large effect size and a standardized response mean.

METHODS: Data came from a large sample of 11,412 Chinese undergraduate students. A bifactor-IRT model, specifying one general strain factor and four specific strains factors, was examined for fit to the sample data. A detailed item analysis, with analysis of the differential item functioning (DIF) of the items across gender, was undertaken to evaluate the dimensionality of the PSS. The associations among the PSS scale scores with scores on the concurrent measures, assessing psychache and suicidal behaviors, were examined.

RESULTS: IRT-derived specific bifactor indices showed that the PSS was unidimensional, and thus the PSS total scores should be reported. Unidimensional subset of 5 items identified (Item 9, Item 12, Item 14, Item 16, and Item 20), using bifactor-IRT modeling and incremental validation, were selected to construct a potential short form of the PSS (PSS-SF). The PSS-SF scale scores demonstrated strong psychometric properties and associations with scores on the concurrent measures assessing relevant constructs.

LIMITATIONS: This study used cross-sectional data from a non-clinical sample of Chinese undergraduate students.

METHODS: Cross sectional observational cohort study. Subjects with normal eyes were recruited. Two sets of optical coherence tomography angiography images of macula and optic nerve head were acquired during one visit. Novel in-house developed software was used to count the pixels in each images and to compute the microvessel density of the macula and optic disc. Data were analysed to determine the measurement repeatability.

RESULTS: A total of 176 eyes from 88 consecutive normal subjects were recruited. For macular images, the mean vessel density at superficial retina, deep retina, outer retina and choriocapillaries segment was OD 0.113 and OS 0.111, OD 0.239 and OS 0.230, OD 0.179 and OS 0.164, OD 0.237 and OS 0.215 respectively. For optic disc images, mean vessel density at vitreoretinal interface, radial peripapillary capillary, superficial nerve head and disc segment at the level of choroid were OD 0.084 and OS 0.085, OD 0.140 and OS 0.138, OD 0.216 and OS 0.209, OD 0.227 and OS 0.236 respectively. The measurement repeatability tests showed that the coefficient of variation of macular scans, for right and left eyes, ranged from 6.4 to 31.1% and 5.3 to 59.4%. Likewise, the coefficient of variation of optic disc scans, for right and left eyes, ranged from 14.3 to 77.4% and 13.5 to 75.3%.

CONCLUSIONS: Optical coherence tomography angiography is a useful modality to visualise the microvasculature plexus of macula and optic nerve head. The vessel density measurement of macular scan by mean of optical coherence tomography angiography demonstrated good repeatability. The optic disc scan, on the other hand, showed a higher coefficient of variation indicating a lower measurement repeatability than macular scan. Interpretation of optical coherence tomography angiography should take into account test-retest repeatability of the imaging system.

METHODS: A cross-sectional observational study was performed on healthy and glaucoma subjects, on whom two sets of OCTA images of optic disc and macula were acquired using both AngioVue (Optovue, USA) and Swept Source (Topcon, Japan) OCTA devices during one visit. A novel in-house software was used to calculate the vessel densities. Diagnostic accuracy of the machines in differentiating healthy versus glaucomatous eyes was determined using area under the receiver operating characteristic curve (AUROC) and test-retest repeatability of the machines was also evaluated.

RESULTS: A total of 80 healthy and 38 glaucomatous eyes were evaluated. Glaucomatous eyes had reduced mean vessel density compared to healthy controls in all segmented layers of the optic disc and macula using AngioVue (p ≤ 0.001). However, glaucomatous eyes had higher mean vessel density on optic disc scans using Swept Source, with lack of statistically significant difference between healthy and glaucomatous eyes. The AUROC showed better diagnostic accuracy of AngioVue (0.761-1.000) compared to Swept Source (0.113-0.644). The test-retest reliability indices were generally better using AngioVue than Swept Source.