Depth perception in patients with congenital color vision deficiency

To assess the effect of type and severity of congenital color vision deficiency (CCVD) on depth perception.

Thirty-one male patients with a known diagnosis of CCVD were included in the study group and 31 age-matched healthy subjects in the control group. After standard ophthalmological examination including best corrected visual acuity (BCVA) testing with Snellen chart, slit-lamp examination, non-contact tonometry, and fundus examination, all patients underwent color perception testing with Hardy-Rand-Rittler (HRR) 4th edition pseudoisochromatic test plates and stereoacuity testing with Titmus stereo test plates.

Of the 31 patients with CCVD, 7 were protanope and 24 were deuteranope. Mean stereoacuity was 46.77 ± 11.3, 105.7 ± 69.0, and 134.1 ± 115.2 in the control, protanope, and deuteranope groups, respectively. Stereoacuity was significantly better in the control group than in the protanope and deuteranope groups (p = 0.039, p < 0.001 respectively). No significant difference was observed between protanopes and deuteranopes regarding stereoacuity (p = 0.73). Mean BCVA was -0.01 ± 0.03, -0.02 ± 0.07, and -0.10 ± 0.11 in the control, protanope, and deuteranope groups, respectively. Mean BCVA in deuteranopes was significantly better than the control group (p = 0.004), while mean BCVA in deuteranopes and protanopes did not differ significantly (p = 0.056). No significant difference was observed between the control group and protanopes regarding visual acuity (p = 0.921).

Our study showed that color vision had an important effect on depth perception and CCVD may cause decreased stereoacuity.