Introduction: Colour vision tests that were originally intended for the study of congenital dyschromatopsias
produce confusing results when applied to patients with acquired diseases. Ishihara test plates primarily designed
for detecting congenital dyschromatopsias, are widely used to detect acquired colour vision defects because of
their convenience, apparent simplicity of administration and availability. This study was done to compare the
results of Ishihara’s test and Roth 28 hue test in identifying and quantification of colour vision abnormalities in
Optic Nerve disorders and to establish patterns of colour vision defects in acquired optic Nerve disorders. Materials
and methods: This was prospective, cross sectional, comparative study done on patients with various optic nerve
disorders attending the OPD from January 2016 to December 2018 were included. 71 patients of various optic
neuropathies were included. All patients underwent comprehensive ophthalmic examination including visual
acuity assessment, slit lamp examination, fundus examination, and IOP measurement. Colour vision was tested
mono-ocularly with Ishihara’s test and Roth 28 Hue test. All the data was tabulated and statistically analysed.
Results: The study included 139 eyes of 71 patients with various optic neuropathies. The mean age was 36 years.
The causes of optic neuropathies included were papilledema, optic neuritis, optic atrophy, glaucomatous optic
neuropathy, and tobacco-alcohol amblyopia. Two patients had Traumatic optic neuropathy and one patient had
non-arteritic ischaemic optic neuropathy. On comparing Ishihara and Roth test, there was statistically significant
correlation between two tests (p<0.001). On comparing BCVA with both the test results, statistically significant
correlation was found. (Ishihara: p=0.001, Roth: p<0.001). Conclusion: Even though Ishihara’s test was designed to
screen congenital colour vision defects, our study shows that it can be still used to detect colour vision abnormalities
in acquired colour vision defects such as optic neuropathies because the results are comparable to arrangement test
such as Roth test.

Keywords: Colour Vision, Ishihara and Roth Test, Optic Nerve Disorders.