Understanding Genetic Vision Loss and Inherited Retinal Diseases
Understanding Inherited Retinal Diseases
Inherited retinal diseases, often called IRDs, are a large group of eye conditions caused by changes in a person's genes. These genetic changes affect the retina. The retina is the thin layer of tissue at the back of the eye that converts light into signals the brain can understand. When a gene that supports the retina does not work properly, the cells in the retina can slowly break down. This leads to vision loss over time.
More than 270 different genes have been linked to various forms of inherited retinal disease (NEI, 2024). Because so many genes are involved, these conditions can look very different from person to person. Even family members who share the same genetic change may experience different levels of vision loss.
Genes carry the instructions that tell cells how to make proteins. Proteins are essential for the retina to function properly. When a gene has a change, also called a mutation or variant, the protein it produces may be made incorrectly or not made at all. Without the right proteins, the photoreceptors (the cells that detect light) or the retinal pigment epithelium (a layer that supports the photoreceptors) can degenerate.
For example, in congenital X-linked retinoschisis, mutations in the RS1 gene affect a protein that helps retinal cells stick together. When this adhesive protein does not work, the layers of the retina can split apart. More than 191 different mutations in the RS1 gene have been identified (ASRS).
Several distinct conditions fall under the umbrella of inherited retinal diseases. Each has its own pattern of vision loss, age of onset, and genetic cause. Some of the most recognized forms include retinitis pigmentosa, Stargardt disease, Usher syndrome, and Leber congenital amaurosis.
- Retinitis pigmentosa (RP) is the most common inherited retinal disease, affecting roughly 1 in 4,500 individuals (Hanany et al., 2020).
- Stargardt disease affects roughly 1 in 17,000 individuals and primarily damages central vision (Hanany et al., 2020).
- Usher syndrome affects roughly 1 in tens of thousands individuals and combines vision loss with hearing loss (Hanany et al., 2020).
- Leber congenital amaurosis affects roughly 1 in 42,000 individuals and can cause severe vision loss in infancy (Hanany et al., 2020).
- Congenital X-linked retinoschisis affects 1 in 5,000 to 1 in 25,000 individuals, primarily males (ASRS).
Who Is Affected and Risk Factors
Inherited retinal diseases are passed from parents to children through genes. The way a condition is inherited depends on whether the genetic change is on a regular chromosome or on the X chromosome. It also depends on whether one or two copies of the changed gene are needed to cause the disease. The main patterns include autosomal dominant, autosomal recessive, and X-linked inheritance.
In autosomal dominant inheritance, only one copy of the changed gene from one parent is enough to cause the condition. In autosomal recessive inheritance, a child must receive the changed gene from both parents. X-linked conditions primarily affect males because they have only one X chromosome. Females with one changed copy are usually carriers who may have mild or no symptoms.
Some people develop inherited retinal diseases as part of a larger syndrome that affects other parts of the body. Usher syndrome, for example, combines retinitis pigmentosa with hearing loss. It is one of the most common syndromic forms of inherited retinal disease.
Stickler syndrome is another genetic disorder that can involve the retina. People with Stickler syndrome may have flattened facial features, skeletal problems, and hearing loss. The vitreous gel inside the eye is abnormally liquid in these patients, which can lead to retinal detachment at an early age. Sickle cell disease can also affect the retina. Abnormal red blood cells can block small blood vessels, cutting off oxygen and causing sickle cell retinopathy.
A family history of progressive vision loss starting in childhood or young adulthood is an important risk factor. However, not every person with an inherited retinal disease has a known family history. Sometimes genetic changes appear for the first time without any affected relatives.
Genetic counseling can help individuals and families understand their risk. A genetic counselor can explain how a specific condition is inherited and what the chances are of passing it to children. Genetic counseling is especially important for couples planning a family when one or both partners carry a known gene variant.
Signs and Symptoms
Many inherited retinal diseases begin in childhood, though symptoms may be subtle at first. Parents or teachers may notice that a child struggles to see in dim light. In some cases, the condition is not detected until a child fails a routine vision screening at school.
Congenital X-linked retinoschisis is typically diagnosed in males between 3 months of age and school age. Early signs can include crossed eyes (strabismus), abnormal eye movements (nystagmus), and lazy eye (amblyopia). When vision loss is mild, it can go unnoticed for years.
In retinitis pigmentosa, vision loss typically follows a recognizable pattern. Night blindness (nyctalopia) is usually one of the first symptoms. Over time, peripheral vision (side vision) narrows, creating what is often described as tunnel vision.
The field of vision continues to narrow into adulthood. Central vision may be preserved for many years, but it can decline as the disease progresses. The speed and extent of vision loss vary significantly from person to person.
While inherited retinal diseases typically progress slowly, certain symptoms require immediate evaluation. A sudden increase in floaters, flashes of light, a curtain or shadow over part of the vision, or sudden vision loss in one eye should be treated as urgent. See a retina specialist or go to the emergency room immediately if any of these symptoms occur.
People with certain inherited conditions, such as Stickler syndrome, have a higher risk of retinal detachment. Knowing these risks and responding quickly to warning signs can help preserve remaining vision.
Diagnosis and Testing
A comprehensive eye examination is the first step in evaluating suspected inherited retinal disease. A retina specialist will examine the retina using specialized instruments. They look for characteristic signs of degeneration, such as bone-spicule pigmentation in retinitis pigmentosa or yellow flecks in Stargardt disease.
Because many inherited retinal diseases share similar features, the clinical exam alone may not provide a definitive diagnosis. Additional testing, including imaging and genetic analysis, plays a critical role.
Several advanced tests help retina specialists evaluate the health and function of the retina. These tests provide detailed information about which retinal layers are affected and how much function remains.
- Optical coherence tomography (OCT) creates detailed cross-sectional images of the retina, showing the thickness and structure of each layer.
- Fundus autofluorescence imaging highlights patterns of retinal cell health and can reveal areas of degeneration.
- Electroretinography (ERG) measures the electrical responses of the retina to light, assessing photoreceptor function.
- Visual field testing maps the areas of vision that are intact and identifies regions of peripheral vision loss.
Genetic testing has become a critical step in diagnosing inherited retinal diseases. Identifying the specific gene change responsible for a person's condition can confirm the diagnosis. Genetic testing involves a blood draw or saliva sample that is analyzed in a specialized laboratory.
Beyond confirming a diagnosis, genetic testing opens the door to gene therapy and clinical trials. Some treatments are designed for specific genetic changes. Knowing which gene is involved determines whether a person may be eligible for these therapies. Genetic testing also provides valuable information for family members who may carry the same variant.
Treatment Options
Luxturna (voretigene neparvovec) was the first gene therapy approved in the United States for an inherited retinal disease. It is designed for people with vision loss caused by mutations in both copies of the RPE65 gene. This condition is known as biallelic RPE65 mutation-associated retinal dystrophy.
Luxturna works by delivering a functional copy of the RPE65 gene directly into the retinal cells using a modified virus as a carrier. The procedure is performed during a vitrectomy (a surgery to remove the gel inside the eye), which allows the therapy to be placed beneath the retina. Genetic testing is required to confirm eligibility. Clinical studies have shown meaningful improvements in the ability to see in low light (FDA, 2017).
Research in inherited retinal diseases is advancing rapidly. Several new approaches are being studied in clinical trials. One promising investigational therapy is MCO-010 (now known as ACDN-01). Instead of replacing a specific faulty gene, MCO-010 is mutation-agnostic. This means it may work across a range of genetic mutations that cause retinal degeneration.
In the RESTORE phase 2b/3 trial, patients with advanced retinitis pigmentosa were treated with MCO-010. Results showed statistically significant improvements in visual acuity at 52 and 76 weeks (RESTORE Trial, 2025). ACDN-01 has received Rare Pediatric Disease and Fast Track designations from the FDA.
While gene therapy and clinical trials offer hope for certain genetic changes, most people with inherited retinal diseases benefit from supportive care and vision rehabilitation. Low vision aids, such as magnifiers, specialized glasses, and electronic devices, can help people make the most of their remaining vision.
Orientation and mobility training teaches techniques for navigating safely with reduced vision. Occupational therapists who specialize in vision loss can help with daily tasks such as reading, cooking, and using technology.
Living with Inherited Retinal Disease
People living with inherited retinal diseases often develop practical strategies for daily activities. Good lighting in the home, high-contrast labels, and talking devices can make a meaningful difference. Many smartphone applications now include accessibility features such as magnification and text-to-speech.
Planning ahead for lighting conditions can help reduce the impact of night blindness. Carrying a small flashlight and wearing sunglasses to reduce glare during the day are simple adjustments that can improve comfort and safety.
The field of inherited retinal disease research is moving faster than at any previous point. New clinical trials are regularly opening for a range of conditions and genetic types. Staying informed about emerging treatments is an important way to advocate for oneself.
Patient registries allow individuals to enter their genetic and clinical information into a database. This can help match patients with clinical trials for which they may be eligible. A retina specialist can also provide guidance on whether upcoming trials may be relevant.
Living with a progressive condition that affects vision can carry a significant emotional weight. The uncertainty of not knowing how quickly vision will change can create anxiety for both patients and family members.
It is important to acknowledge these feelings and seek support. Many people find it helpful to connect with others through patient advocacy organizations and support groups. Mental health professionals who understand chronic health conditions can provide valuable coping strategies.
When to See a Retina Specialist
Anyone who notices difficulty seeing in low light, progressive narrowing of peripheral vision, or unexplained vision loss should see a retina specialist. Children who fail vision screenings, have crossed eyes, or show signs of abnormal eye movements should also be referred.
If there is a family history of inherited retinal disease or a known genetic syndrome that involves the eyes, a retina specialist can provide screening and testing even before symptoms begin.
Certain symptoms require immediate medical attention. A sudden increase in floaters, flashes of light, a shadow or curtain falling over part of the visual field, or sudden loss of vision in one eye are serious warning signs. See a retina specialist or go to the emergency room immediately. These symptoms may indicate a retinal detachment or other urgent condition that requires prompt treatment.
Questions and Answers
Yes, in many cases. If a family member has been diagnosed and the responsible gene change has been identified, other family members can undergo genetic testing. Early imaging and functional testing by a retina specialist may also detect subtle retinal changes before a person notices any vision problems. Early detection is especially important because it allows for baseline measurements and may open the door to clinical trials.
Genetic testing is strongly recommended even when a clinical diagnosis exists. Many inherited retinal diseases share overlapping features, so genetic testing can confirm or refine the diagnosis. It also identifies the specific gene change responsible for the condition. This information is required for eligibility for gene therapies such as Luxturna (voretigene neparvovec) and for enrollment in most clinical trials.
Luxturna (voretigene neparvovec) is currently the only FDA-approved gene therapy for an inherited retinal disease. It is specifically for biallelic RPE65 mutations. Most other forms do not yet have an approved gene-specific treatment. However, mutation-agnostic therapies and cell replacement approaches are in clinical trials. Supportive care, including low vision rehabilitation and assistive technology, remains important for all types.
The risk depends on the specific inheritance pattern of the condition. Genetic counseling is the best way to understand these risks. A genetic counselor can explain whether the condition follows autosomal dominant, autosomal recessive, or X-linked inheritance. In some cases, carrier testing for partners can further clarify the likelihood of a child being affected.
The recommended frequency depends on the specific condition, the rate of progression, and whether a person is receiving treatment. In general, most retina specialists recommend evaluations at least once or twice per year. More frequent visits may be needed if the condition is progressing or if the patient is being considered for a clinical trial. A retina specialist will recommend a schedule based on individual circumstances.