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Classification of iris colour: review and refinement of a classification schema

journal contribution
posted on 2023-05-17, 11:48 authored by David MackeyDavid Mackey, Wilkinson, CH, Kearns, LS, Alexander HewittAlexander Hewitt
Eye colour or, more accurately, iris colour is one of the most obvious physical characteristics of a person. European parents frequently ask the colour of their newborn's eyes, only to see the iris change dramatically during their child's first year of life. Genetic and epidemiological findings have uncovered further details about the basis for iris colour, which may have important implications for further research and treatment of some eye diseases and ocular characteristics. Surprisingly there is no widely recognized classification system for eye colour. An added difficulty when trying to devise an international system is that subtle differences in colour description exist between languages (e.g. hazel vs. auburn). We reviewed the recent and very early literature pertaining to eye colour classification. Recent genetic investigations of eye colour have tended to either use simple (three-category grading systems) or more complex digital colour grading. We present a nine-category grading system. Categories in this novel schema include: (i) light blue; (ii) darker blue; (iii) blue with brown peripupillary ring; (iv) green; (v) green with brown iris ring; (vi) peripheral green central brown; (vii) brown with some peripheral green; (viii) brown; and (ix) dark brown. Although different observers may categorize a person's eye colour differently, it is generally only by an adjacent category. We also describe a continuum of iris pigmentation from a small ring of brown around the pupil to almost complete brown with small peripheral flecks. Digital publishing and assessment of iris colour will result in more standardized classification of iris colour and investigation of its role in eye disease.


Publication title

Clinical and Experimental Ophthalmology










Tasmanian School of Medicine


Wiley-Blackwell Publishing Asia

Place of publication


Rights statement

Copyright 2011 Royal Australian and New Zealand College of Ophthalmologists

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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