The excited 5-year-old was in the office for his kindergarten physical and his school forms were all in order. His mother was really on top of things and quickly nodded yes when I asked if the boy had already gone for his state-required dental and eye exams.
The mother added that though his eye doctor appointment had gone well, the boy had been diagnosed with a minor form of color blindness. The condition wasn't expected to impact his everyday life since he only had difficulty distinguishing a few subtle shades of color. Mom remarked on the inheritability of this eye condition, recalling that her own father had also been color blind.
According to the National Institutes of Health Genetics Home Reference, "color vision deficiencies" are usually caused by genetic mutations. Genetic changes alter the function of the cones, which are the light receptor cells in the retina responsible for accurate color vision.
The three recognized types of inherited color blindness are red-green color vision defects, blue-yellow defects -- which cause difficulty in distinguishing shades of blue from green and yellow from violet, and achromatopsia -- the complete lack of color vision. Color defects can also develop as a result of diseases affecting the retina, optic nerve or brain.
Red-green color vision defect is the most common form of genetic color blindness. This defect is, in fact, found in 99 percent of color blind individuals. Experts at the NIH report that the incidence of the red-green defect is highest in people of northern European background, affecting 8 percent of males and only 0.5 percent of females in this subgroup.
Boys make up the overwhelming majority of this group since red-green color blindness has an X-linked recessive pattern of inheritance, with a mutated gene passing from unaffected mother to her colorblind son via the X chromosome.
Elizabeth Cooper and her colleagues at the Nevada Dual Sensory Impairment Project note that 75 percent of people with red-green color vision deficiency have problems with green perception, while 25 percent struggle with reds. The more subtle pastel shades of both colors cause the most difficulty for affected viewers.
The Nevada educational team finds that color blindness is a minor inconvenience for most affected schoolchildren. Color vision defects can, however, cause problems since students are often expected to differentiate colors on classroom graphs and whiteboards. Color blindness can also be socially challenging as affected kids try to coordinate matching clothes for each school day.
Cooper's group has a few tips to make school easier for color blind children, suggesting that teachers maximize color contrast on educational displays whenever possible and label items when color recognition is vital to the particular project or lesson plan.
Parents and kids can also prep for school by labeling colored pencils and crayons and by organizing and labeling clothing by color. In certain situations, it can also be helpful for color blind children to learn to identify colors based on location, such as the red at the top and the green at the bottom of a real-life or school-behavior "traffic light."
• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights.