Achromatopsia is an inherited condition that affects approximately 1 in every 33,000 Americans.
Achromatopsia is a rare genetic autosomal recessive disorder that is also known as total color blindness and complete achromatopsia. Basically, autosomal recessive disorder means that patients have received the abnormal gene from both parents and not just one. This condition presents with photophobia (eye discomfort in bright light), reduced visual acuity, nystagmus, and complete monochromacy (the complete inability to distinguish colors). In about 75 percent of cases, mutations in the CNGB3 and CNGA3 genes are responsible for the condition.
In children, achromatopsia is typically first detected around six months of age because of symptoms of photophobia or nystagmus. With age, the nystagmus becomes less noticeable, while the other symptoms of the syndrome become more prominent. During the first six to seven years of life, visual acuity improves but remains around 20/200. Other than that, it does not worsen as a person ages and is considered stable.
Children and adults with achromatopsia may have difficulty with everyday activities such as reading, driving, watching TV, playing sports, using their phone or computer, recognizing faces, walking outdoors or indoors, using maps, etc. Today, state-of-the-art low vision aids are available that may allow achromats to do many of these activities that you previously couldn't. Our low vision optometrists will evaluate your vision during a low vision evaluation and prescribe low vision aids based on the tasks that are important to you. Below is a list of some low vision aids and strategies:
If you or a loved one has been diagnosed with achromatopsia and has been told that nothing more can be done, we urge you to schedule a low vision evaluation with our low vision optometrist.
At present, there is no cure for achromatopsia; however, several clinical trials are recruiting patients to participate in gene replacement therapy for CNGA3 and CNGB3. These genes are responsible for achromatopsia. Meanwhile, the focus of treatment is on alleviating symptoms and improving remaining vision.
Patients with achromatopsia usually have good peripheral vision, mild and stable vision loss, and are considered ideal bioptic driving candidates. However, patients with complete achromatopsia have problems with traffic lights, brake lights and reading certain colored signs. Many of these patients can now drive using bioptic telescopes with the help of red central contact lenses and modifications that make it easier for them to see traffic signals.
A bioptic telescope consists of a pair of glasses with a telescope attached above your normal line of sight. These can be attached to your regular eyeglasses and can be used either for one or both of your eyes. Bioptic lenses magnify images just like binoculars and help you see things better. Using these lenses allows you to see things that are much further away, which is one of their main benefits.
Patients with achromatopsia can benefit from achromatic soft contact lenses with custom designed filters. These contact lenses are designed to reduce the light that enters the eye which helps with light sensitivity. Custom-fitting is essential to ensure the correct level of darkness, the best filter color, and the size of the filtered area for each patient.
Red central contact lenses
With red central contact lenses, patients with achromatopsia can open their eyes naturally in daylight without squinting as they reduce the light entering the eyes.
B30 contact lenses
In comparison with red central contact lenses, these lenses look much better on the patient's eyes due to their dark brown appearance. A lot of patients prefer these lenses for their cosmetic value as well as their ability to improve their vision.
B60 contact lenses
These lenses also appear dark brown on the patient’s eyes and are darker than B30 contact lenses. Light-sensitive patients are ideal candidates for these contact lenses.
Achromatopsia is a syndrome characterized by symptoms of five different eye disorders
In a global survey, photophobia was ranked as the most distressing and frustrating symptom for adults with achromatopsia.
Children who suffer from achromatopsia may:
In a healthy human, there are approximately 6 million cone photoreceptors and 120 million rod photoreceptors. The cones are responsible for providing you with central vision and color vision. When these are affected, it results in reduced visual acuity and may also cause total color blindness. On the other hand, rods make it possible for us to see at night and in dim light. The rods are also responsible for peripheral vision. When the rod cells don’t work, it can result in night blindness and peripheral vision loss.
There are two types of achromatopsia: complete and incomplete. Complete achromatopsia causes more severe symptoms than incomplete achromatopsia. Patients with incomplete achromatopsia only suffer color blindness and their visual acuity is affected whereas patients with complete achromatopsia suffer from total color blindness, nystagmus, photophobia, reduced visual acuity and hemeralopia.
According to a global survey, 23% of children were incorrectly diagnosed with retinal or cone dystrophy prior to receiving an accurate diagnosis of achromatopsia. Over a period of more than five years, adults with achromatopsia typically see an average of seven healthcare providers. One third of these individuals were initially diagnosed with retinal or cone dystrophy before being accurately diagnosed with achromatopsia. That is why it is very important to see our low vision optometrist as soon as you or your child start exhibiting symptoms that are listed above.