Comparison of two colour vision tests used in current ophthalmic practice

Abstract

Objectives: To determine the validity of Richmond 4th edition HRR test, as a screening test to detect colour blindness, using Ishihara's test as a standard test and to do comparison between these two tests in the diagnosis of congenital colour blindness. Patients and methods: This is a prospective study done on 150 patients attending Ophthalmic Outpatient Clinic at Al-Jumhory Teaching Hospital / Mosul-Iraq from the 1stof January till 30th of June 2012. Results:150 subjects was enrolled in the study, age range 15-25 years, mean 20.67 years  2.74, males:130 (86.67%), females:20 (13.33%). Seven subjects discovered to have congenital red-green deficiency using Ishihara’s colour vision test, while 12 subjects have same problem while using Richmond HRR 4th edition, three of whom have mild defect, seven have moderate defect, and two only had sever defect. No such grading is possible with Ishihara’s test. HRR test had the highest sensitivity and PVN (100%), very high specificity and LR+ (96.5%) and (28.57) respectively, but poor PVP (58.33%) in the diagnosis of congenital colour blindness. The overall accuracy of HRR test in diagnosing colour vision defects was (96.67%). Conclusion: Richmond 4th edition HRR test is as good as Ishihara’s test in detecting congenital red-green colour deficiency, and have an advantage over Ishihara's of grading the severity of the defect.