ABSTRACT
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.
ABSTRACT
BACKGROUND: Prolonged exposure to infrared (IR) radiation is associated with different types of damage to cornea and lens. The aim of our study was to investigate the effect of acute and chronic exposure to IR radiation on the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9 and on the expression of glycosaminoglycans (GAG) in the rabbit cornea and crystalline lens. METHODS: New Zealand rabbits were subjected to IR radiation for 4 months (chronic exposure to IR) or to normal light (control group). In experiments regarding acute exposure, animals were subjected to IR radiation or normal light for 12 h, in the presence of 0.1% diclofenac sodium (eye drops instilled in the right eye of animals) or saline (instilled in the left eye of animals). The cornea and lens were dissected away and homogenized. The activity of MMP-2 and MMP-9 was assayed by gelatine zymography. Total GAG were isolated from tissue specimens after lipid extraction and extensive digestion with pronase and DNase and characterized by treatment with GAG-degrading enzymes, followed by electrophoresis on cellulose acetate membranes. RESULTS: Acute or chronic exposure to IR radiation induced the activity of MMP-2 in cornea and lens, whereas only acute IR radiation increased the content of heparan sulphate in crystalline lens. Local administration of diclofenac sodium did not prevent the above effects of acute IR radiation. CONCLUSIONS: The detrimental effects of excessive or prolonged exposure of the eyes to IR radiation are associated with induced activity of MMP-2 in cornea and lens and alterations in the content of heparan sulphate in lens. Thus, MMP and GAG may offer alternative targets for pharmacological intervention to confront ocular damages associated with IR radiation.
