Comparison of vergence mechanisms between university students with good and poor sleep quality.

AIM: To compare the vergence mechanisms between good and poor sleepers in university students. METHODS: A total of 64 university students were recruited in this study. The validated Malay version of Pittsburgh Sleep Quality Index questionnaire (PSQI-M) was used to measure the participants' sleep quality over the past month. Participants were categorized as good sleepers (n=32) and poor sleepers (n=32) based on the PSQI-M scores. Heterophoria and fusional vergences were measured at distance and near. Mann-Whitney U test was used to compare heterophoria, negative fusional vergence (NFV), and positive fusional vergence (PFV) at distance and near between good and poor sleepers. Spearman correlation analysis was used to study the relationship between PSQI-M score and PFV at distance. RESULTS: Both distance and near heterophorias were not significantly different between good and poor sleepers (P>0.05). There was a difference in distance PFV (P<0.05) between good and poor sleepers, but not in distance NFV, near NFV, and near PFV (P>0.05). Distance PFV was negatively correlated with PSQI-M score (rs=-0.33, P<0.05). CONCLUSION: University students with poor sleep quality demonstrates a reduced ability to maintain fusion with increasing convergence demand at distance. Sleep quality assessment during binocular vision examination in university students is recommended.

Fear of detachment from mobile phone: nomophobia and suicidality among Malaysian university students before and during the COVID-19 pandemic.

The attachment to mobile devices during the COVID-19 pandemic has led to the possibility of increased nomophobia, which is the intense fear of losing access to one's mobile device. Therefore, this study aimed to determine if nomophobia was independently associated with suicidality before and during the COVID-19 pandemic among university students in Malaysia. This cross-sectional study had two-time points in data collection: one year before and one year into the COVID-19 pandemic. N = 806 university students aged ≥ 18 years completed an online questionnaire comprising the Nomophobia Questionnaire, Multidimensional Scale of Perceived Social Support, and the Suicidal Behaviors Questionnaire-Revised. A multiple logistic regression (controlling for gender, age, and social support) was conducted to determine the association between nomophobia and suicidality before and during the COVID-19 pandemic. The prevalence of severe nomophobia before and during the COVID-19 pandemic was 15.7% and 35.6% respectively. The level of nomophobia was significantly higher during the COVID-19 pandemic compared to pre-pandemic. Pre-pandemic, there were no significant associations. During the pandemic, participants with moderate (aOR 3.09, 95% CI [1.14-8.40], p = .027) and severe (aOR 3.57, 95% CI [1.25-10.20], p = .018) nomophobia had higher odds of suicide plan. During the pandemic, moderate and severe nomophobia were independently associated with more than three times higher odds for a lifetime suicide plan. Our study findings carry implications for the well-being of university students.

Review of Evidence for the Usage of Antioxidants for Eye Aging.

Oxidative stress is one of the common factors leading to age-related eye diseases in older adults. Factors such as high oxygen consumption, high concentration of polyunsaturated fatty acids, and cumulative exposure to high-energy visible light in the eyes, lead to excessive generation of reactive oxygen species, hence triggering apoptosis of ocular cells and giving rise to ophthalmic diseases. Dietary supplements such as carotenoids, anthocyanins, and vitamins have antioxidant properties which may be of benefit in retaining better vision or reversing vision impairment; thus, studies have been conducted to understand the role of dietary supplements in the treatment or prevention of ophthalmic diseases. While high concentration of carotenoids such as lutein and zeaxanthin decrease the risk of developing age-related macular disease, anthocyanins and vitamins play a role in the treatment and prevention of other ophthalmic diseases: saffron extract reduced intraocular pressure in glaucoma patients; bilberry extract prevented impairments in lenses and retina, as well as alleviate symptoms of dry eye disease; high concentration of beta-carotene may reduce the risk of developing cataract. Further studies with clinical measurements are required to investigate the effectiveness of antioxidants on visual function and ophthalmic diseases.

Visual acuity measured with luminance-modulated and contrast-modulated noise letter stimuli in young adults and adults above 50 years old.

The human visual system is sensitive in detecting objects that have different luminance level from their background, known as first-order or luminance-modulated (LM) stimuli. We are also able to detect objects that have the same mean luminance as their background, only differing in contrast (or other attributes). Such objects are known as second-order or contrast-modulated (CM), stimuli. CM stimuli are thought to be processed in higher visual areas compared to LM stimuli, and may be more susceptible to ageing. We compared visual acuities (VA) of five healthy older adults (54.0±1.83 years old) and five healthy younger adults (25.4±1.29 years old) with LM and CM letters under monocular and binocular viewing. For monocular viewing, age had no effect on VA [F(1, 8)= 2.50, p> 0.05]. However, there was a significant main effect of age on VA under binocular viewing [F(1, 8)= 5.67, p< 0.05].  Binocular VA with CM letters in younger adults was approximately two lines better than that in older adults. For LM, binocular summation ratios were similar for older (1.16±0.21) and younger (1.15±0.06) adults. For CM, younger adults had higher binocular summation ratio (1.39±0.08) compared to older adults (1.12±0.09). Binocular viewing improved VA with LM letters for both groups similarly. However, in older adults, binocular viewing did not improve VA with CM letters as much as in younger adults. This could reflect a decline of higher visual areas due to ageing process, most likely higher than V1, which may be missed if measured with luminance-based stimuli alone.