PURPOSE: The present study aims to look at the association between CH and severity of OSAS, and whether CH could be another link between OSAS and the development of glaucoma.
METHODS: This was a cross-sectional, observational study at the University Malaya Medical Centre, Kuala Lumpur. Patients undergoing polysomnography for assessment of OSAS were recruited. We measured central corneal thickness (CCT) using optical biometry, and CH using ocular response analysis. Intraocular pressure (IOP) and Humphrey visual field (HVF) indices were also measured. The Apnea Hypopnea Index (AHI) divided patients into normal, mild, moderate, and severe OSAS categories. The normal and mild categories (47.9%) were then collectively called group 1, and the moderate and severe categories (52.1%) were called group 2. T tests, Pearson correlation tests, and general linear model analysis were performed, with P .05). CH correlated negatively with AHI (r = -0.229, P = .013) and positively with lowest oxygen saturation (r = 0.213, P = .022).
CONCLUSIONS: CH is lower in moderate/severe OSAS than in normal/mild cases. This may be another link between OSAS and the development of glaucoma; further studies are indicated to determine the significance of this connection.
PURPOSE: The purpose of this study was to compare habitual visual acuity in a sample of young children using two versions of the single Lea symbols charts with different crowding features.
METHODS: Monocular habitual visual acuity was measured in a sample of 77 young children aged between 4 and 6 years using crowded Lea symbols charts with either flanking bars separated from the central symbol by 0.5 optotype width or flanking Lea optotypes separated from the central symbol by 1.0 optotype width.
RESULTS: Mean visual acuity was higher (i.e., lower logarithm of the minimum angle of resolution) with the Lea symbols crowded using flanking optotypes, equivalent to about 1.5 optotype difference. Visual acuity measured with the two charts was significantly correlated; however, the 95% limits of agreement were larger than expected from repeatability studies using Lea symbols.
CONCLUSIONS: Lea symbols with flanking optotypes resulted in higher visual acuity than the Lea symbols with flanking bars, probably as a result of differences in the crowding effect. The two charts showed insufficient agreement, and we do not recommend their use interchangeably. We recommend using the Lea symbols with flanking bars because of the closer flanker-target separation.