Cone rod dystrophy2022-08-11T08:58:27+00:00

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Cone rod dystrophy: Glasses,
Symptoms, Causes, Diagnosis, and Treatment Options.

Last updated: July 30, 2022

Cone rod dystrophy: Glasses,
Symptoms, Causes, Diagnosis, and Treatment Options.

Last updated: July 30, 2022

Share

Cone rod dystrophy is an inherited eye condition affecting people of all ages. The genetic mutations are passed from parents to their children due to the deterioration of cones and rods in the eye. It results in decreased visual acuity, increased light sensitivity, color vision impairment, central vision blind spots, and loss of peripheral vision. Due to the progressive visual impairment, cone rod dystrophy vision can be life- changing. Though there is no specific treatment for cone rod dystrophy, there are ways to manage the symptoms and slow down the progression of the eye disease, like genetic therapy, as well as the use of assistive technology visual aids to improve the remaining sight and quality of life.

From this point on, we'll help you in identifying various aspects of cone rod dystrophy, such as its diagnosis, symptoms, risks, and treatments.

What is Cone Rod Dystrophy?

Cone rod dystrophy is a group of 35 inherited diseases that cause deterioration of the specialized light sensitive cells, cones and rods of the eye.

Light is a vital aspect that carries visual information from our surroundings and enters the eye, striking the light-sensitive tissues lining the back of the eye, i.e. the retina. The retina converts the information from light to electric pulses that are sent to the brain by optic nerves. Once the light signals are perceived by the brain, we are able to see.

Cone dystrophy and cone rod dystrophy are caused by genetic changes in one of the 35 genes, affecting the normal function of cone photoreceptor cells in the retina. As a result, the cells degenerate over time and eventually die, causing vision loss and even partial or legal blindness.

Cone rod dystrophy statistics tell us that this condition affects 1 in 20,000 to 100,000 people worldwide. An estimated number of people with rod cone dystrophy may be between 3,000 to 30,000 in the U.S.

How Do Our Eyes Function

Our eyes are one of our body's most complicated systems, capable of perceiving great quantities of detail and allowing us to perceive objects both close and far away.

The eye is made up of a network of muscles, nerves, and vessels. However, which part of the eye lets us see? What are the cells called that detect light, which allows us to see?

The photoreceptor cells: cones and rods in the eye.

To understand the function of rods and cones in the eye, we need to look at the most important part of the eye, the retina. Cones and rods are the two types of photoreceptor cells within the retina. They are responsible for receiving signals or images, processing them, and sending them to the brain.

The cones and rods have different functions to perform, yet they work towards the same goal… to help us see.

What Is the Main Function of Rods in the Eye?

The rods are responsible for our vision in low light levels or “scotopic vision”. They are more sensitive than the cones, which enables us to perceive shapes and objects in dimly lit places. Our eyes take some time to adjust from a well-lit room to a dark room or outside during the nighttime. This happens because the rods take around 30minutes to fully adjust in the absence of light.

Another function of rods in the eye is to act as motion sensors. As the rods are positioned in our peripheral field of view, motion detection is most predominant there.

What Is the Main Function of Cones in the Eye?

The cones are responsible for color vision and are made up of three types of receptors. These receptors are called, short, medium, and long wavelength cones. The sizes of these cones determine their light sensitivity.

The most important difference between cones and rods is their light sensitivity. Cones are more light-sensitive than the rods and require a lot more light than rods to send signals to the brain. Hence, this is the reason why we cannot differentiate colors in dimly lit places.

Due to the requirement for increased light levels, cones are mainly responsible for our visual acuity. A defective cone will lead to a loss of the ability to focus on certain objects or perceive colors.

With this information, you now know how important it is for the cones and rods in the eye to function properly to see objects around you. The rods determine the level of light around you, while the cones perceive colors and the sharpness of the objects. Together, they are the foundation of our normal vision.

Cones and Rods Deterioration

Rod cone dystrophy is an inherited condition. Therefore, it develops when genetic mutations are passed from parents to their children. These mutations cause the degeneration of cones and rods in the eye. Due to this, the sharpness of vision decreases, light sensitivity increases, color vision is impaired, blind spots appear in the central visual field, and peripheral vision is partially affected.

In rod cone dystrophy, cones usually breakdown before rods. Hence, you lose color vision and have higher light sensitivity as the first symptoms. Further down the progression, night blindness may occur and the ability to read or perform actions with peripheral vision is impaired. The deterioration of the photoreceptors can be bad enough for a person to not even be able to perform their everyday life tasks.

Is Cone Rod Dystrophy The Same As Retinitis Pigmentosa?

Retinitis Pigmentosa (RP) is a group of inherited diseases caused by gene mutations that affect the retina. In RP, the photoreceptors do not work properly, causing vision loss. However, it is quite different from cone rod dystrophy. While night blindness and impaired color vision are the most common and early symptoms of cone rod dystrophy, Retinitis Pigmentosa causes loss of peripheral vision or difficulty adjusting vision in the dark.

Both eye conditions are inherited, have mutated genes, and affect the photoreceptors of the eye. Yet, why are the initial symptoms different? This is because in RP, the rods are affected, which are responsible for our peripheral vision and vision in dim lights. Though the rods are affected first in Retinitis Pigmentosa, as the eye disease progresses, it can make it harder to see details and process light.

Cone Rod Dystrophy Vision Outlook

Cone rod dystrophy is a progressive eye disease, which affects the visual acuity, causes photophobia, scotomas, progressive night blindness, and peripheral vision loss. 

Due to loss of visual acuity, difficulties arise in recognizing faces and facial expressions, focusing on faraway objects, reading print, and performing visual tasks in fine detail. To use the remaining vision effectively with cone rod dystrophy, a person can be taught to increase contrast of their surroundings.

Bright lights and glare cause discomfort in cone rod dystrophy vision, leading to the inability to see properly, known as whiteout. As the rods in the eyes are damaged, peripheral vision loss occurs, leading to a certain degree of tunnel vision.

In addition to other conditions, cone rod dystrophy may lead to central vision loss. Hence, making it difficult to perform everyday tasks.

Clinically validated and approved, IrisVision’s assistive low visual aids are being used by people with visual impairments for everyday tasks. Try it today.

Signs and Symptoms of Cone Rod Dystrophy

Cone rod dystrophy age of onset can be as early as childhood and may not be corrected with glasses. The early-stage cone rod dystrophy symptoms include difficulty in recognizing small details or decreased visual acuity, and abnormal light sensitivity. As the condition progresses, it affects an individual's peripheral vision, color perception, and blind spots may occur in the central vision.

Here are some symptoms along with their frequency that may occur in rod cone dystrophy:

  • 80% to 90% of people have:
    • Abnormal retinal pigmentation, which causes a change in the color of the retina.
    • Night blindness, causing an inability to see at night or in poor light.
    • High sensitivity to light, causing discomfort or pain in the eyes when exposed to bright lights.
  • 30% to 70% of people have:
    • Abnormal color vision, causing an inability to differentiate colors.
  • 5% to 29% of people have:
    • Visual impairment, causing limitation of vision.

Many people with cone rod dystrophy, due to low vision, are at risk of injury while indoors or outdoors. They also suffer from reduced mobility, and inability to recognize faces. These risks are prevalent for people of all ages; however, cone rod dystrophy in children makes it especially important for them to learn how to navigate the world early before the progression of the disease worsens.

Does Cone Rod Dystrophy Cause Blindness?

Complete blindness is not common for people with cone rod dystrophy. However, people in the late stages of the eye condition may be legally blind. People suffering from cone dystrophy and cone rod dystrophy, declared legally blind, use specialized glasses, braille, and other tools to help improve mobility and vision.

What Causes Cone Rod Dystrophy?

As discussed, different types of cells build up the complex structure of the retina and work together to help us see. The 35 genes identified so far account for only 60% of the cases of cone rod dystrophy. There are genes yet to be identified.

The genes involved in cone rod dystrophy are responsible for providing instructions to create proteins that are necessary for the healthy development and functioning of retinal cells. A single defect in any of these genes causes a disruption in the smooth working of the retina and leads to vision loss.

Different types of cone rod dystrophies happen based on the inheritance pattern of the genes. Here’s an overview of the inheritance patterns.

  • Autosomal recessive is the most common inheritance pattern of cone rod dystrophy. Both copies of the gene are mutated and do not work properly. Hence, both the mother and father passed on the mutated gene.
  • In an autosomal dominant pattern, one copy of the gene does not work properly. Here, the affected person receives one copy of the mutated gene from an affected parent.
  • If the male has an X-chromosome with a mutated gene, only one copy of the X-chromosome contains the gene. Since females have another X-chromosome functioning, they usually do not develop the condition. This is the X-linked inheritance pattern. Females with a non-random X-chromosome, on the other hand, can have cone rod dystrophy symptoms.

Sporadic causes of cone rod dystrophy happen when new genetic mutations may occur.

Diagnosis of Cone Rod Dystrophy

After analyzing the presenting symptoms, performing a clinical examination, and performing an electroretinogram (ERG), an electro-diagnostic test of the retina, cone rod dystrophy progression can be detected.

The ERG helps assess the overall function of the photoreceptor cells of the retina. During this procedure, sticky patches are placed around the eyes and attached to wires that lead to a machine that records the electrical signals. If the signals are weak or absent, then cone rod dystrophy is likely the cause.

During this examination, the cone function is highly reduced in cone dystrophy and cone rod dystrophy. However, the rod function is preserved in cone dystrophy. While the rod function is less affected than the cones in cone rod dystrophy.

Preventive Tips for Cone Rod Dystrophy

Currently, there is no approved treatment for cone rod dystrophy. However, there are management and preventive measures one can take to avoid further cone rod dystrophy progress. Some of these tips are:

  • Regular monitoring of visual function and prescribed glasses
  • Tinted glasses or contact lenses for light sensitivity
  • Hats or UV protected sunglasses
  • Sunlight diffusers in cars to ease light sensitivity
  • A diet rich in fresh fruits and green leafy vegetables
  • Avoid Vitamin A supplements for ABCA4 mutations
  • Screen protectors against blue light

Current Research on Cone Rod Dystrophy

Current research for cone rod dystrophy is focused on finding the remaining causative genes and understanding how the disease progresses. Results from trials to test Stargardt disease can open doors to the development of new therapies. Other studies with a similar role include:

  • Gene therapy for retinitis pigmentosa; mutations in the RPGR gene
  • Gene therapy for Leber’s Congenital Amaurosis; mutations in GUCY2D gene
  • Gene therapy for achromatopsia; mutations in the CNGA3 gene

Is There Any Treatment for Cone Rod Dystrophy Cure

As mentioned earlier, there is no approved rod cone dystrophy treatment that can help improve vision. There is research and studies underway, exploring different solutions. However, a concrete cure hasn’t been identified.

To help people with cone rod dystrophy, it is recommended to get in touch with a vision specialist to learn about how to prevent vision loss and tools to counteract the loss of vision. Tools like assistive technology and the support of family, friends, support groups, and health care providers can help cope with the condition.

Here are some treatment options that can help manage cone rod dystrophy symptoms and progression.

Cone Rod Dystrophy Gene Therapy

Gene therapy is among the most promising methods of treating rod cone dystrophy. Clinical trials are still underway to discover how gene and stem cell therapy can stop or reverse the damage of rod cone dystrophy.

Ayurvedic Treatment

Several anecdotal accounts state that ayurvedic treatment can work on cone rod dystrophy. However, this hasn’t been scientifically proven yet. A consultation with an ayurvedic practitioner wouldn't hurt to help with the overall eye health and slow the progression.

Vitamins and Supplements for Cone Rod Dystrophy

Some vitamins and supplements can help support the photoreceptor cells function. To learn about which vitamins and supplements to use, consult with your ophthalmologist. Nutrients like omega-3 fatty acids, vitamin C, and taurine help enhance the retina’s health.

Glasses for Cone Rod Dystrophy: Assistive Wearable Glasses

By now, we all know that cone rod dystrophy is a progressive eye disease and a non-preventive one to boot. With the advances in technology, assistive wearable glasses like IrisVision can help people with cone rod dystrophy live an easy and comfortable life.

IrisVision Inspire is an electronic eyewear that leverages and improves the remaining vision of people with visual impairments. By enhancing the remaining vision of a person with cone rod dystrophy, they can perform all their daily lives activities without much difficulty.

Someone suffering from cone rod dystrophy with photophobia as a symptom can use IrisVision effectively by adjusting the brightness and contrast of the surroundings and screens to fight off light-sensitivity.

Regain Independence

Cone rod dystrophy vision, which causes difficulty performing everyday tasks, can be enhanced with IrisVision wearable assistive visual aid. It helps people with low vision:

  • Read newspapers, books, labels, and documents
  • Watch TV, even when in a dark room
  • Recognize the faces of loved ones
  • Enjoy outdoors
  • Pick up old hobbies (knitting, sewing, board games, etc.)

Overall, IrisVision is a FDA registered Class-I medical device with the ability to improve vision. Read more user experiences and reviews here: Customer Stories.

FAQ

What does a person with cone-rod dystrophy see?2022-07-29T09:35:08+00:00

A person with cone rod dystrophy has difficulty seeing small details, is sensitive to light, has reduced peripheral or central vision, blind spots, or has night blindness.

Does Rod Cone Dystrophy cause blindness?2022-07-29T09:35:52+00:00

People with cone rod dystrophy are rarely declared completely blind. It usually leads to low vision or partial blindness. However, in the severe late stages of the condition, a person may develop legal blindness or night blindness.

How is cone-rod dystrophy diagnosed?2022-07-29T09:36:37+00:00

An ophthalmologist performs a dilated eye exam to assess the condition of the cones and rods in the eye. Any degeneration may indicate cone rod dystrophy. Another method of diagnosis is genetic testing.

Is Rod Cone Dystrophy the same as retinitis pigmentosa?2022-07-29T09:37:38+00:00

Retinitis Pigmentosa is a form of cone rod dystrophy. In RP, the rods are affected before the cones, leading to symptoms of having difficulty seeing at night or in dimly lit places.

What causes cone-rod dystrophy?2022-07-29T09:38:46+00:00

Cone rod dystrophy occurs when mutations in certain genes happen. There are around 35 genes linked with cone rod dystrophy. The condition is inherited in an autosomal recessive, dominant, and X-linked pattern.

Is there a cure for retinal dystrophy?2022-07-29T09:39:58+00:00

Currently, there is no approved treatment or cure available for cone rod dystrophy. However, there are ways and technologies that can assist in managing the condition’s progression and improving vision.

Can rods and cones regenerate?2022-07-29T09:41:41+00:00

The cones and rods in the eye cannot regenerate naturally. Research is currently underway to accomplish this feat through genetic and stem cell therapy.

How quickly does retinal dystrophy progress?2022-07-29T09:42:57+00:00

Cone rod dystrophy is a progressive eye condition that gets worse with time. Though the symptoms start gradually, they increase as the degeneration continues.

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