To Assess the Effect of Lighting on Identifying the Ishihara Colour Vision Plates in Trichomats

Aims: The main aim of present study is to investigate the effect of luminance on identifying the Ishihara colour vision plates in normal trichromats.

Place and Duration of Study: Dr. Rishi Bhardwaj Visual Psychophysics laboratory, School of Medical sciences, University of Hyderabad-INDIA, 1-year (07/2015 to 07/07/2016).

Methodology: This experimental quantitative study design conducted with n=60 participants of age group 18 to 21 years both male & female genders and inclusion criteria was trichromats, emmetropes with no history of ocular pathology and randomized sampling was done to study the experiment in lab setting with three different illuminations (Compact fluorescent light- CFL), fluorescent light, LED light) with constant 400-lux is maintained for the experiment followed by colour vision assessment with Ishihara colour vision plates 38th edition (printed) version. Followed by satisfactory and feedback of comfort was received by participants.

Results: The relation between lighting and isochromatic colour vision plates response was not statistically significance (P=0.007) males & females (P=0.056). But the isochromatic plate identifying speed is faster (1 - 3 sec) under fluorescent lighting compare to CFL and LED, similarly the distribution of symptoms related to colour vision was very less in fluorescent lighting (10-30%) followed by CFL (10-55%) and maximum (30 – 75%) under LED lighting, shown more symptomatic. Satisfactory feedback from sixty participants showed that 36 participants recommended (Fluorescent=63%) lighting was good while identifying ishihara colour vision plates followed by CFL and LED similarly, 12 recommended (CFL=20%) and 10 participants recommended (LED=17%).

Conclusion: This experiment concludes that ishihara colour vision plates are a tool for red and green deficiency screening. But the luminance intensity and types of lighting play a vital role for discriminating the numerals that imbedded in isochromatic plates, fluorescent lighting showed better results and faster speed to recognize the isochromatic plates compare to CFL and LED luminance in trichromats.