Comparison of Ishihara and Hardy-Rand-Rittler Pseudoisochromatic Plates in Non-Arteritic Anterior Ischaemic Optic Neuropathy

A Novel Smartphone-Based Color Test for Detection of Color Vision Defects in Age Related Macular Degeneration

Purpose

To evaluate the efficacy of the smartphone-based K-color test to detect color defects in patients with Age-related Macular Degeneration (AMD).

Methods

88 patients (n = 135 eyes) with AMD and 28 controls (n = 53 eyes) underwent color testing with the Hardy–Rand–Rittler (H-R-R), the K-color test, and the Ishihara test. The K-color test presents randomized colored shapes in decreasing steps of intensity, providing also a record system for result tele-transmission. Sensitivity, specificity, and reliability were examined to investigate the validity of the novel test. 26 participants with AMD also completed a questionnaire regarding the feasibility of the test.

Results

Linear mixed-effects models indicated a significant difference (p < 0.001) between AMD and normal eyes. The areas under the curve (AUC) were estimated to be 0.897 [95% CI: 0.841–0.952], 0.943 [95% CI: 0.901–0.984], and 0.931 [95% CI: 0.886–0.977] for the red, green, and blue color, respectively. Based on the H-R-R, the sensitivity of the test was 0.79, 0.90, and 0.95 for the red, green, and blue colors, respectively, and specificity was 0.88 for all colors. The new test recognized more abnormal cases than the Ishihara (sensitivity of 0.98 and 1.0 and specificity of 0.48 and 0.38 for red and green colors, respectively). Test-retest reliability was found to be high for the red [ICC = 0.996 (0.990–0.999)], green [ICC = 0.974 (0.929–0.990)], and blue [ICC = 0.992 (0.981–0.997)] colors. The majority of the asked participants stated that they could easily perform the test.

Conclusion

The K-color test was found to be sensitive and specific in detecting color defects in AMD patients. The K-color test may serve as a useful tool both for patients and their physicians.

Can Protanopia Be Correctly Diagnosed in Clinical Practice? An Evaluation of Diagnosis by Four Screening Tests

SIGNIFICANCE

Protanopia is a color vision deficiency (CVD) that is unacceptable for certain occupations. This study compares simultaneously for the first time the ability of three recently revised or developed clinical tests of color vision with the Ishihara test to diagnose protanopia from other color vision deficiencies.

PURPOSE

The objectives were to examine the ability of four clinical tests to differentiate (1) between protan and deutan CVDs in patients with protanopia and deuteranopia, and (2) protanopes and deuteranopes as "strong" deficiencies.

METHODS

The Hardy-Rand-Rittler (4th ed.), City University (3rd ed.), Ishihara, and Mollon-Reffin tests were evaluated against the Oculus Heidelberg Multi-Color anomaloscope for 18 protanopes and 9 deuteranopes. Diagnosis by anomaloscopy was subsequent to administration of screening tests.

RESULTS

The Ishihara test misdiagnosed all 18 protanopes as having a deutan deficiency. In contrast, the Hardy-Rand-Rittler and Mollon-Reffin tests correctly identified protan CVD in 100% of protanopes. No screening test was able to reliably diagnose protanopia on the basis of a strong protan CVD.

CONCLUSIONS

The Ishihara test is not suitable for screening for protanopia; its failure to diagnose protanopes as having a protan CVD was far greater than that in previous studies. The Hardy-Rand-Rittler and Mollon-Reffin are the most reliable tests for this purpose. None of the screening tests were able to reliably differentiate dichromacy from strongly anomalous trichromacy.

The effect of reduced contrast sensitivity on colour vision testing

OBJECTIVE

To assess the effect of reduced contrast sensitivity on three commonly used colour vision tests in order to establish key discrepancies that may be relevant for clinical practice.

METHODS

A prospective non-interventional clinical study of colour vision testing using three commonly used devices: Ishihara and Hardy-Rand-Rittler (H-R-R) pseudoisocochromatic plate tests, and Farnsworth D-15 arrangement test performed under progressively reduced contrast sensitivity conditions achieved with a neutral density filter bar.

RESULTS

The Pelli-Robson contrast sensitivity (PRCS) at which 5% of the population should first experience a 10% reduction in colour vision testing from baseline was calculated for each of the three colour vision devices: Farnsworth D-15 test: 1.81 log contrast sensitivity (CS), H-R-R test: 1.69 log CS, and Ishihara test: 1.34 log CS. Single factor repeated measures analyses, conducted separately at each contrast sensitivity level, revealed no difference between the colour vision testing devices at PRCS ≥1.80 log CS (P ≥ 0.367). However, in all PRCS ≤1.65 log CS, the differences were statistically significant (all P ≤ 0.004), demonstrating a significantly lower percentage of errors in the Ishihara test compared with both the Farnsworth D-15 (P < 0.023) and H-R-R (P < 0.035) tests.

CONCLUSIONS

At high contrast sensitivities, all colour vision tests function almost equally; however, at decreased levels of contrast sensitivity, H-R-R and Farnsworth D-15 are more greatly affected.