Ocular Albinism (OA) is a rare, genetic eye condition that predominantly affects males due to its X-chromosome-linked recessive nature. While the term “albinism” may cause one to think of pale skin or hair color, Ocular Albinism occurs exclusively within a person’s eyes, affecting both their vision and the way their eyes look. OA is usually diagnosed during childhood, and currently, there is no cure. However, there are plenty of supportive options that can make living with Ocular Albinism manageable.
Ocular Albinism (ICD-10 code: E70.319) is an inherited condition in which a person lacks pigmentation in their eyes. Pigment is what gives the iris of an eye its color—typically, blue, brown, or green—and is an essential component in proper eye function. The job of the iris is to control the amount of light entering the eye. Pigment helps to make the iris more opaque, which in turn, blocks more light.
The lack of pigmentation associated with OA stems from a person’s lack of melanin in the eye. Melanin also acts like sunscreen to protect the eyes from the sun’s harmful UV rays. Ocular Albinism can cause vision problems, such as nearsightedness, farsightedness, and astigmatism.
Ocular Albinism affects not only the retina, which is the light-sensitive tissue that lines the inside of the eye, but also the optic nerve, which sends information about what a person sees to the brain. Being a congenital condition, individuals with OA do not fully develop their retinas, which severely impairs the sharpness of their vision. This causes vision to appear blurry and out of focus.
Unlike most other types of albinism, Ocular Albinism does not noticeably affect a person’s skin or hair color. Some individuals with OA may have slightly lighter skin pigmentation than other family members, but the differences in complexion are usually minor.
Prevalence of Ocular Albinism
Ocular Albinism is a rare condition. According to the National Organization for Rare Disorders, it occurs in roughly one male for every 20,000 births. While females can be affected, cases are exceedingly rare.
Ocular Albinism (OA) vs Oculocutaneous Albinism (OCA)
Albinism is a term that applies to a group of hereditary conditions that denote a lack of pigmentation in the body. Albinism can be broadly divided into two categories: Ocular Albinism (OA) and Oculocutaneous Albinism (OCA). When the eyes are affected, but the skin and hair are not, this is referred to as Ocular Albinism. Oculocutaneous Albinism, on the other hand, refers to conditions that affect the hair, skin, and eyes. All forms of albinism can have negative effects on vision. While albinism may occur as part of a larger syndrome, such as Hermansky-Pudlak syndrome or Chediak-Higashi syndrome, this is rare.
Ocular Albinism Type 1 vs Type 2
Ocular Albinism can be broken down into two types. Type 1, also known as Nettleship-Falls Ocular Albinism, is the most common, and affects about 1 in 60,000 men. Type 1 OA is caused by mutations in the GPR143 gene, and is typically an X-linked recessive disorder. Both Ocular Albinism Type 1 and Type 2 usually only affect the pigment of the eyes, while the skin and hair are relatively unaffected. OA Type 1 is frequently linked with nystagmus, a condition characterized by involuntary rapid and repetitive eye movements.
Ocular Albinism Type 2, also known as Forsius–Eriksson syndrome, is far rarer than Ocular Albinism Type 1 (less than 1 in 1 million men are affected). OA Type 2 is very similar to Type 1—in fact, almost identical. However, unlike OA Type 1, OA Type 2 results from mutations in the CACNA1F gene, and is frequently linked with protanopic dichromacy, which is a type of color blindness, as well as night blindness.
What is X-Linked Ocular Albinism (XLOA)?
X-Linked Ocular Albinism (XLOA) refers to inherited Ocular Albinism through the X chromosome, one of the two sex chromosomes. Both Ocular Albinism Type 1 and Type 2 fall into this category. Biological males have one X chromosome, so one altered copy of the GPR143 gene in each cell is enough to cause the characteristic symptoms of Ocular Albinism. Biological females have two X chromosomes, which means that they must inherit a copy of the GPR143 mutation from each parent to present with Ocular Albinism. Women with one copy of this mutation, however, can pass the genetic mutation on to their offspring. X-Linked Ocular Albinism makes up the majority of Ocular Albinism cases.
Signs and Symptoms
Ocular Albinism affects the retina and the nerves behind the eyes. Due to the underdevelopment of the retina, people with OA most commonly present with poor sharpness of vision (visual acuity). This results in blurry vision as the nerves behind the eyes cannot transmit a clear image to the brain.
Reduced visual acuity can cause a variety of challenges, especially for children. For example, poor vision can interfere with a children’s ability to participate at school and in sports. In addition, adults may have trouble driving and performing activities that involve complex hand-eye movements.
Symptoms of Ocular Albinism include:
- Vision impairment, such as extreme nearsightedness or farsightedness
- Rapid, back-and-forth eye movements, known as nystagmus
- Head movements, such as tilting or bobbing the head, usually as an effort to reduce nystagmus and to see better
- The inability of the eyes to move in unison or stay directed on the same point
- Poor depth perception
- Legal blindness
Ocular Albinism can also cause strabismus, commonly known as crossed or “lazy” eyes. Many people with this condition experience hypersensitivity to bright light and glare, a condition known as photophobia.
Since albinism prevents the body from making enough melanin, the chemical that gives skin, hair, and eyes its color, the physical appearance of eyes is also affected. Most people with Ocular Albinism have blue eyes. However, blood vessels inside the eyes may be visible through the pale iris, making them seem pink or red.
Permanent vision loss is also possible for individuals with Ocular Albinism, but the symptoms do not worsen over time.
If you have a child with albinism that experiences frequent nosebleeds, easy bruising, or chronic infections, you should contact your doctor. These symptoms may be a result of Hermansky-Pudlak syndrome or Chediak-Higashi syndrome. These are rare but serious disorders that include albinism.
Yes, Optic Atrophy can cause blindness. Its effect can be from anywhere mild vision changes to complete loss of vision.
General Range Of Acuity Measured In Individuals with OA
Vision professionals measure visual acuity by the ability to discern letters and numbers at a fixed distance, with perfect vision scoring 20/20. Ocular Albinism can reduce visual acuity to anywhere from 20/60 to 20/400, according to the National Organization for Albinism and Hypopigmentation (NOAH).
Is Ocular Albinism Progressive or Degenerative?
Ocular Albinism is not a progressive or degenerative condition. Visual impairments may be permanent, but they will not worsen over time. In fact, some children with OA may experience improvement in their visual acuity as they age. People with Ocular Albinism will never go completely blind, except if another disorder or condition is present, although they may be considered legally blind.
Effects on the Fovea
One of the most important components of the eye is the fovea, a specific area in the retina responsible for sharp vision. Unfortunately, the fovea does not develop properly in people with OA, resulting in blurred vision. The fovea relies on melanin and pigment for proper eye development, which is complicated in the presence of OA.
Effects on the Optic Nerve Fibers
The optic nerve fibers of people with OA follow a different neurological path than those without the condition. Nerve fibers normally transmit to both sides of the brain, such that some nerve fibers go to the same side as the eye and some fibers go to the opposite side of the brain. However, in people with OA, more of the nerve fibers cross over to the opposite side of the brain than is considered normal. This phenomenon has also been noted in individuals with Oculocutaneous Albinism.
Doctors can diagnose X-linked Ocular Albinism by examining a patient’s eyes and family history. Female relatives who carry the gene for OA may have some abnormalities in the pigment of their retinas. However, they usually will not present with the visual symptoms associated with OA. With infants, signs like nystagmus can be visible within 3 to 8 weeks. However, reduced visual acuity may not be noticeable until the child is old enough to recognize objects and other figures. Genetic testing for mutations in the GPR143 gene may be used to confirm a diagnosis.
Diabetes is a condition associated with high blood sugar levels (hyperglycemia). Excessive amounts of sugar in the bloodstream can damage blood vessels within the retina, leading to swelling and leakage. Hyperglycemia also permits sugar to accumulate in the eye’s lens, which can change the curvature of the lens and thus affect vision.
Over time, damaged blood vessels can completely prevent blood from reaching the retinal tissue. In such cases, new blood vessels may form on the surface of the retina to supply the retina with the oxygen-rich blood it needs to function. As the condition worsens, however, the new blood vessels may also leak into the back of the eye, which leads to vision loss.
While Ocular Albinism may presently be incurable, that doesn’t mean that patients can’t lead happy, healthy lives. Indeed, many resources are available for people with OA, including vision correcting devices, support groups, and low vision aids.
Glasses and contact lenses can help sharpen vision for people with OA. Some also find handheld magnifiers to be very helpful. Sunglasses, transition lenses, or special filter glasses can relieve hypersensitivity to light, although they may reduce visual acuity when worn indoors. However, changes to indoor lighting can help someone with OA to see better.
People with Ocular Albinism should be tested by an ophthalmologist annually. The eye doctor can make sure the person has the proper strength glasses and/or contact lenses to help them improve their vision.
While OA may be rare, it’s helpful for patients to know that they aren’t alone. Support groups, such as NOAH and the National Association of Parents of Visually Impaired (NAPVI), are great places for parents to learn valuable information about the condition and share tips for managing it with their children. Support groups associated with NOAH and Council of Citizens with Low Vision International help children and adults learn about the condition, feel less isolated, and learn healthy coping skills from others.
Increasingly, technology is being utilized to help improve the lives of people living with OA. For example, devices like low vision eyewear can stimulate synaptic activity from the remaining photoreceptor function of its users’ eyes, significantly enhancing their vision. These revolutionary tools are dramatically improving the lives of patients