Achromatopsia is a rare, inherited disorder that affects vision. Symptoms include light sensitivity, nystagmus, decreased vision, and loss of some or all color vision.
If achromatopsia runs in the family and your child has these or other vision problems, it's important to have his or her vision evaluated by an optometrist or ophthalmologist. Although there is no cure for achromatopsia, there are options available to manage the symptoms:
Achromatopsia is a visual disorder characterized by an abnormality of the retina in which cones needed for color vision are absent. Retinal receptor cells not only contribute to color vision, but they also play a role in the eye's ability to perceive fine detail and adjust to different levels of light. When these cones are missing or malfunction, a child can have partial or complete achromatopsia.
Inheritance Connection Explained
A child inherits the gene responsible for achromatopsia from both parents. Since parents each carry the abnormal gene on only one of two paired chromosomes, they do not develop the visual disorder. Achromatopsia is an autosomal recessive disorder that requires the defective gene on both of the chromosomes in a pair. While parents or even grandparents may not have the condition, one or more of a child's siblings can have achromatopsia.
Eye and Vision Problems Evaluated
Although usually not first detected at birth, squinting is often an early sign of achromatopsia. Another early symptom that presents in infants is nystagmus, or repetitive, involuntary eye movements.
In addition to considering a child's own symptoms, an eye doctor will inquire about family history of eye and vision problems. An ophthalmologist will also examine your child's retina—although usually the retina looks normal—and test his or her visual acuity. Before diagnosing achromatopsia, your child will have color vision testing to assess his or her ability to perceive colors and electroretinogram testing to measure electrical responses of the retina to light.
Aside from genetic testing, electroretinography is another test doctors use to confirm the diagnosis of achromatopsia. However, since electroretinography is difficult for infants and young children under the age of 5 who can't hold still, they are usually sedated so that the doctor can perform the test.
The rods and cones in the retina at the back of the eye are sensitive to light and color. Therefore, electroretinography testing involves the placement of a small electrode, which resembles a contact lens, on the front of each eye. An electrode is also placed on the skin.
A monitor then records the retina's response to flashes of light in normal lighting and in darkness. The A waves and B waves the monitor records show if parts of the retina aren't working.
Children with achromatopsia often have refractive errors such as astigmatism, nearsightedness, or farsightedness that can be improved with prescription eyeglasses. Treatment for congenital nystagmus includes corrective eyeglasses, contact lenses, and prisms in lenses to improve vision.
Your child's eye doctor may recommend wearing sunglasses or red-tinted contact lenses to reduce light sensitivity, allowing for better vision in bright light. Large print and magnifiers also help children with low vision achromatopsia allow them to see better when reading.
Contact a medical office like Dixie Ophthalmic Specialists at Zion Eye Institute for more information and assistance.