PURPOSE: To develop a standardized method for measuring from iris photographs, light and dark segments of areas and densities of iris color. METHODS: Computerized image analysis was used to measure the iris photographs. The reproducibility of this method was studied in 30 normal eyes with three different colored irides, green-brown, blue-grey brown and yellow-brown. Three photographs were taken of each iris with a slit lamp camera at three different exposures at baseline. The photographs were repeated with exposure providing for the best reproducibility at 6.5 +/- 1.7 months as a first follow-up after baseline and 3.6 +/- 0.8 months following the first follow-up visit. At least one measurement was made for each photograph. RESULTS: The mean percent coefficient of variation (standard deviation of triplicate measurements/mean x 100) ranged from 1.0 to 4.1% for area and density measurements. Furthermore, the range of mean percent differences between baseline and follow-up visits ranged from 1.2 to 6.3%. CONCLUSION: We have developed a standardized method which appears suitable for measuring changes over time in iris color.
PURPOSE: To develop a standardized method for measuring from iris photographs, light and dark segments of areas and densities of iris color. METHODS: Computerized image analysis was used to measure the iris photographs. The reproducibility of this method was studied in 30 normal eyes with three different colored irides, green-brown, blue-grey brown and yellow-brown. Three photographs were taken of each iris with a slit lamp camera at three different exposures at baseline. The photographs were repeated with exposure providing for the best reproducibility at 6.5 +/- 1.7 months as a first follow-up after baseline and 3.6 +/- 0.8 months following the first follow-up visit. At least one measurement was made for each photograph. RESULTS: The mean percent coefficient of variation (standard deviation of triplicate measurements/mean x 100) ranged from 1.0 to 4.1% for area and density measurements. Furthermore, the range of mean percent differences between baseline and follow-up visits ranged from 1.2 to 6.3%. CONCLUSION: We have developed a standardized method which appears suitable for measuring changes over time in iris color.