Ralph D. Gunkel

Color vision and age in a normal North American population

Color vision is known to change with age. We conducted the Farnsworth-Munsell (FM) 100-Hue and the Lanthony Desaturated Panel D-15 (DD-15) tests in 115 normal North American subjects aged 5–81 years to obtain age-specific norms for these procedures. For each test, color discrimination was best between the ages of 20 and 50 years. Both increasing age and the occurrence of lens changes were significantly associated with increasing 100-Hue error scores. Age-specific norms for the 100-Hue test were comparable with those obtained by Verriest in a European population, but such norms for the DD-15 test are problematic. Our data indicate somewhat greater variability in the DD-15 than in the 100-Hue test.

The pupil dark response in normal volunteers

A new semi-automatic videopupillometer with a two-channel video integrator uses prismatic displacement of pupil images for binocular recording with a single infrared-sensitive video camera. The video integrator graphically records pupil area or diameter during testing and can reanalyze and plot information from videotape recordings of pupil responses. This new pupillometer was used to evaluate the pupil dark response in 178 eyes of 89 normal human volunteers (ages 18-75 years). The time course of pupil dilation was similar in volunteers of all ages, even though the average pupil area became progressively smaller with increasing age.

Saturation Discrimination and the Degree of Diabetic Retinopathy

A blue-yellow deficiency is generally observed when color vision is altered secondary to diabetes. What is not clear, however, is the relationship between the degree of retinopathy and the degree of color deficiency. We have measured spectral saturation discrimination (from 430–680 nm) in normal and diabetic subjects as the first perceptible step from a white reference field (x = 0.45, y = 0.43). We used an optical system which permitted the patient to vary colorimetric purity (at constant luminance) by adjusting a single control knob. Constancy of luminance was assured by preliminary measurement of each patient’s relative luminosity function. All diabetic subjects had normal visual acuity. Diabetic patients without retinopathy showed normal saturation discrimination functions. However, in patients with retinopathy, there was little correlation between losses in saturation discrimination and the degree of retinopathy. That is, a patient having minimal retinopathy, can manifest the same loss in saturation discrimination as a patient having severe background retinopathy.

A Chromaticity Diagram for Defects in Color Vision

An instrument is described for the measuring and plotting of color thresholds. A chromaticity circle is proposed as being more suitable and convenient than the conventional modified triangle for color designation, and particularly useful for describing defects in color vision, both as a function of degree and of spectral range.

Lanthony desaturated panel D15 test in sickle cell patients

The Lanthony D15 desaturated test was used to compare color vision in sickle cell patients with 20/20 visual acuity and peripheral lesions of sickle cell retinopathy with normal controls. Sickle cell patients had significantly higher Lanthony error scores and significantly more blue-yellow and mixed color vision defects than controls. Among patients with sickle cell anemia (SS), Lanthony and Farnsworth Munsell 100 Hue test scores were significantly correlated, and both tests showed good agreement in identifying the presence or absence of a color defect. These results suggest that the Lanthony D15 test may be a useful clinical tool to identify blue-yellow color defects, especially because of its brevity and simplicity of administration.