Evaluating the level of visual acuity to minimise false-positives in different colour vision tests

CLINICAL RELEVANCE

Accurate colour vision assessment is important in clinical settings to minimise false-positive errors and enhance the reliability of diagnoses outcomes.

BACKGROUND

Colour vision testing is valuable in assessing the visual system, particularly given the high proportion of individuals with poor vision. This study aimed to determine the minimum visual acuity level required to perform a colour-vision test without errors.

METHODS

After fogging the right eyes of 52 healthy participants using plus lenses to 1.60 logMAR, vision was evaluated using Ishihara, Hardy - Rand - Rittler Standard Isochromatic, Waggoner Pseudo-isochromatic, City University, Waggoner Computerised, and Farnsworth D-15 tests. Participants then completed these tests at lower fogging degrees (in 0.1-logMAR intervals). The acuity at which 5% of the tested population was considered abnormal was determined.

RESULTS

Significant differences were found in the average visual acuity required to perform colour vision tests without errors (p < 0.05). The Waggoner Computerized test required the highest average visual acuity among the tests utilised. The Farnsworth D-15 test yielded the highest logMAR values. No significant differences were observed between the Waggoner Pseudo-isochromatic test and Hardy - Rand - Rittler Standard Isochromatic, Ishihara, and Farnsworth D-15 tests (p > 0.05). Additionally, no significant differences were found between the Ishihara and Hardy - Rand - Rittler tests (p > 0.1) or between the Waggoner Computerized and City University tests (p = 0.11). Colour vision testing maintained an accuracy ≤ 1.0 logMAR with the Ishihara and Hardy - Rand - Rittler tests, 1.1 logMAR with the Waggoner Pseudo-isochromatic and Farnsworth D-15 tests, and 0.9 logMAR with the Waggoner Computerized and City University tests.

CONCLUSIONS

Insights are provided into the visual acuity thresholds required for accurate colour vision testing, which can serve as a basis for future research and provide a reference for clinical practice in this field.

Assessment of Risk Perception of COVID-19 Post Vaccination amongst the General Population of Riyadh Region

COVID-19 is a highly contagious disease caused by SARS-CoV-2. Vaccination against the virus was first approved in Saudi Arabia in December 2020. Vaccinated individuals are still at risk of getting infected with the virus and can transmit the disease. Therefore, the perception of vaccinated individuals regarding the disease can help limit the spread of the virus.

OBJECTIVES

To measure the risk perception of COVID-19 following vaccination and factors that have an effect on risk perception; to identify the health protective behaviours of the vaccinated individuals.

METHODOLOGY

This is a quantitative analytical cross-sectional, questionnaire-based study. The target population includes individuals aged 18 and above who live in the Riyadh region and have been vaccinated, during the period of June 2021 to December 2021.

RESULTS

The perception of 30.2% of participants did not change after vaccination, with many participants continuing to "always" take precautions even after vaccination. Numerous factors, such as age, gender, marital status, occupational status, employment status, and total household income, have shown significant effects towards risk perception.

CONCLUSION

Many vaccinated individuals have continued to take precautionary steps and their risk perception has not changed.