The assessment of colour vision with the Ishihara test in patients with glaucomatous optic neuropathy

Pei‐Fen Lin1, Shanil Dhanji2,3, Gus Gazzard1, Ana Quartilo1, Mitchell Lawlor2,3

Meeting:  2019 RANZCO


Date:      -

Session Title: Glaucoma

Session Time:      -

Purpose: Although a range of colour vision tests have been evaluated in glaucoma patients, there is limited published data regarding the most widely used, relatively inexpensive and easy to administer colour vision assessment, the Ishihara test. This study assessed how the Ishihara score varies in patients with glaucoma, and whether it is influenced by the severity or location of glaucomatous visual field defects.

Method: Consecutive patients seen in a glaucoma clinic at Moorfields Eye Hospital were assessed. Patients with an Ishihara score of less than 12 out of 14 plates were considered abnormal. Visual fields were assessed with a 24‐2 Swedish interactive threshold algorithm (SITA) standard on the Humphrey visual field (HVF). Statistical assessment was used to evaluate whether Ishihara colour abnormalities were related to the severity or location of the glaucomatous visual field defect.

Results: 218 eyes of 109 patients were recruited. 80% had primary open‐angle (POAG), 13% chronic angle closure and 7% secondary glaucoma. 33 (15%) eyes had an abnormal Ishihara score. No correlation was found between the Ishihara score and either the HVF mean deviation (MD), or reduced sensitivity at any of the four paracentral test points.

Conclusion: the Ishihara test is not uncommonly abnormal in patients with GON. Routine use of Ishihara colour vision testing in glaucoma patients appears to be of limited benefit, as it is frequently abnormal, and the degree of colour deficit does not correlate with severity or location of visual field loss.