Determination of Luminance Levels of Visual Acuity Charts in Selected Eye Clinics in Owerri and Their Effects on Vision

Aim: The study on the determination of the luminance levels of visual acuity charts in selected eye clinics in Owerri and their effects on vision, was carried out in 14 eye clinics in Owerri, Imo State.

Study Design: The study design employed in this study was the quantitative type of design, involving the measurement of variables.

Place and Duration of Study: This study was carried out in Owerri, Imo State, Nigeria, between February, 2019 and November, 2019.

Methodology: A total number of 159 young adult volunteers (60 males and 99 females), which summed up to 318 eyes, between the ages of 18 and 35 years, were used for this study. Using a photometer and internally illuminated visual acuity charts, the visual acuity charts’ luminances and visual acuities of the volunteers were measured respectively, under bright ambient examination room illuminations. The t test: two-sample assuming unequal variances statistical method was used to determine if there was a statistical difference in visual acuity, under various visual acuity chart luminance levels.

Results: Visual acuity chart luminance was found not to differ significantly (since p(t<=t)= 0.44 > P = .05)). Fluorescent luminance was found to have no significant effect on right and left eyes’ visual acuities (since p(t<=t)= 7.29 > P = .05)). Tungsten luminance was found to have no significant effect on right and left eyes’ visual acuities (since p(t<=t)= 3.54 > P = .05)).

Conclusion: This study showed that visual acuity was not affected by chart luminance, under bright ambient room illuminations.