A novel system for the objective classification of iris colour and its correlation with response to 1% tropicamide

Abstract

Iris colour can provide an enormous amount of information about an individual. In addition to changes with pathological conditions, the colour of the iris can be a particularly useful indicator of how well a person will respond to a topically applied ocular drug. Until recently, classification of iris colour has been subjective, ranging from a basic description ('light' and 'dark') to more detailed grading systems, such as a comparison with preset photographic standards. However, variability within observers and differences in the interpretation between observers can influence the results. Objective techniques, in this respect, possess several advantages. They are able to detect differences in colour that subjective techniques are incapable of and they provide continuous data rather than discrete categories, thus improving the accuracy of drug response predictions. This study assessed iris colour by objective means. Slit-lamp photographs of various coloured irides were taken under standardised conditions. The slides were then scanned into a computer and the colour analysed using a calibrated software package. To establish the optimum colour parameter to be used for predictions of drug response, several parameters were calculated and compared with the subject response to 1% tropicamide (maximum change in pupil size, time to maximum change and total duration of effect). Many parameters had strong correlations with drug response, but the parameters 'z', 'b' (the proportion of blue in the image) and 'y' (the proportion of yellow in the image) were found to exhibit the highest correlations. They also showed better correlations with drug response than did a current iris colour grading system.

Iris color and texture: A comparative analysis of real irises, ocular prostheses, and colored contact lenses

“…In several articles, relationships have been established between the color of irises and various physiological conditions. [1][2][3] In addition, color is the key to the relatively recent use of irises as a biometric tool, in which their specific texture is also taken into account, [4][5][6] although one must have in mind that final appearance of human irises depends on other factors such as the color of the skin.…”

Colorimetric measurements of iris colour and their significance in East Asian patients with skin cancer

“…Images of the iris are considered as unique and individual as fingerprints. Iris colour is known to depend on the amount of melanin pigment present in tissues, 1 and skin melanin content has been reported to be positively correlated with iris colour, 2 suggesting that iris colours provide information about the skin. Most importantly, a light‐coloured iris has been repeatedly reported to be a risk factor of skin cancer 3–6 .…”

“…However, the validity of this finding in East Asian populations is doubtful. Although objective measurements of iris colour have been performed by several research groups, 1,7 subjective iris‐colour classification systems were used 8,9 . Furthermore, these studies were viewed as being unsuitable for the East Asian populations because of a relative homogeneity of iris colour in these populations.…”

Extract and Classification of Iris Images by Fractal Dimension and Efficient Color of Iris

“…Iris color and pattern creation is based on Melanin Pigments and Crypts counts. Human iris color has a wide range, so that we can use these different colors for documentation [16]. This range is changing from dark brown to light blue [17].…”