Introduction: Unequal retinal image size (RIS) or aniseikonia is usually related with anisometropia. Higher dif- ferences of RIS may manifest symptoms such as dizziness, headache or disorientation. In worst case might cause suppression that leads to amblyopia. Current study aims to evaluate the consistency of aniseikonia measurement in Smart Optometry smartphone application among myopic, hyperopic, and astigmatic simulated anisometropia and real anisometropia groups. Methods: Fifteen real anisometropes (refractive error; -0.50 until -6.00 diopters; D) and fifteen emmetropes (refractive error: -0.25 until +0.50D) were recruited. Real anisometropes wore their habitual spectacle correction while each emmetropes were fitted using soft contact lenses of +4.00DS, -4.00DS and -4.00DC with base curve 8.6 and total diameter 14.2mm in random order to mimic myopic-, hyperopic- and astigmat- ic-anisometropia before testing. Participants with any ocular disease and binocular vision problem were excluded. The consistency of aniseikonia measurement was determined in two visits, separated by at least 24-hour interval. Three repetitive measurements were taken in each visit. Results: Independent t-test and paired t-test showed that real and simulated anisometropia gave insignificant aniseikonia percentage, p>0.05. ICC findings revealed moder- ate-to-good agreement for all simulated and real groups. Bland Altman analysis between two visits exhibited good agreement among all simulated group; myopic (mean difference 0.2047; 95%CI:-1.1386-1.549), hyperopic (mean difference 0.2200; 95%CI:-0.9286-1.3686) and astigmatic (mean difference 0.2533; 95%CI:-0.7114-1.2180). Real anisometropes demonstrated good agreement with bias value of 0.2247(95%CI:-0.9162-1.3656) using Bland Altman plot. Conclusion: Smart Optometry application provides consistent measurement of aniseikonia regardless any types of anisometropia.
Eye tracking is a technology used to track and record what the human eye perceives. It has been applied in detecting visual field loss, determining infant’s preferential looking and virtual reality therapy. In reading tasks, eye tracking needs to be accurate because even a substantial head movement can affect its fixation accuracy; as such, using a headrest can minimise head movements and the associated fixation errors. This experimental study was conducted to determine the effect of headrest usage on eye tracker fixation accuracy during reading aloud activity by comparing a group with headrest and a group without it. The results showed that the difference between the two groups was significant (p=0.004), where the headrest group and non-headrest group introduced a mean fixation error of 30.728 ± 15 mm and 17.671 ± 9 mm respectively. Eye tracking accuracy for the headrest group was then compared with a standard value of 0.6 degrees. The findings showed that the accuracy was significantly different (p
Introduction: The purpose of the study was to compare the size of visual field in horizontal and vertical, peripheral retinal sensitivity at mid- and far-peripheral temporal viewing using different sizes of stimuli between football athletes and age-gender matched non-athlete subjects. Methods: The participants comprised 9 experienced male football (23.44 ± 2.74 years) players and the control group comprised 9 age-matched male non-athletes (23.33 ± 2.96 years). The parameters were measured using Oculus Twinfield automated perimeter. Horizontal and vertical size of visual field was measured using manual kinetic strategy. The mid-peripheral (60deg) and far-peripheral (90deg) temporal retinal sensitivity in different sizes of stimuli were measured using manual static strategy. The measurement of each test was repeated three times, and then the most reliable value was taken from the three readings. Results: The results from athletes and non-athletes did not differ in regards to peripheral visual attention in all measured parameters (p>0.05). However, athletes group showed slightly better results than non-athletes group. Conclusions: Improved visual performance in selected parameters among athlete group in this study supports previous studies with hypothesis of visual skill in athletes is better compared to non-athletes.
Introduction: Short-term fasting may influence intraocular pressure (IOP) due to alteration of fluid (total body water;
TBW, and water intake) and fat (total body fat; TBF). This study aimed: i) to compare IOP values within and between,
fasting and non-fasting periods; and ii) to assess the association between IOP and, TBW and TBF. Methods: Thirty
healthy participants aged 21.8±1.1 years were assessed on two different periods (fasting vs. non-fasting). During each
period, the IOP, TBW and TBF values were assessed for four times (morning, afternoon, evening, late-evening). The
IOP was measured using AccuPen® tonopen, while TBW and TBF were assessed by using a Tanita body composition
analyser. Results: During fasting, the IOP value in the afternoon (14.53±2.33 mmHg) was significantly higher than in
the evening (12.43±2.73 mmHg, p=0.009) and late-evening (12.60±2.44 mmHg, p=0.003). No significant difference
in IOP was observed during non-fasting period. The mean of IOP in the evening was significantly lower during fasting
compared to non-fasting (12.43±2.73 mmHg vs 13.75±2.53 mmHg, p=0.044). The IOP and TBW were negatively
correlated (r=-0.268; p=0.011) during non-fasting and showed no association during fasting period. There was no
significant correlation between IOP and TBF during both fasting and non-fasting periods. Conclusion: IOP reduction
during short-term fasting, together with the no association with TBF and TBW suggested that IOP is an independent
factor that reduces during fasting in healthy population.