Eye health is extremely important for people’s quality of life. For this reason; such erroneous information that we get from friends and family and social media, such as stye in the eye passes with garlic, cataract can be treated with drops, there is no need for routine eye control in children if there is no complaint, threatens our eye health.

Ophthalmology Specialist Assoc. Prof. Dr. Özge Begüm Comba explained 10 erroneous information about eye health that is thought to be true in the society; made important suggestions and warnings. Pointing out that erroneous beliefs in the society can prevent early diagnosis and treatment of eye diseases, she said, “Delay in the treatment of diseases can cause serious eye problems such as permanent vision loss in the future. For example, conjunctivitis, which is common in our country and popularly known as ‘red eye’ disease, can lead to visual defects and even loss of vision if not treated on time. In addition, in some diseases such as lazy eye, which can be completely eliminated with early diagnosis and treatment, children lose the chance of treatment when it is late. Myopia, which is quite common in our country, can also progress if not followed up regularly.”

Eye Number Increases as You Wear Glasses: False!

There is a widespread belief in the society that the eye number will progress as you wear glasses. Assoc. Prof. Dr. Özge Begüm Comba pointed out that glasses are only an apparatus that allows us to see well and said, “Therefore, wearing glasses will not progress or stop the numbers. It is important to wear glasses especially in childhood for the visual system to work fully and completely. Because glasses are a part of the treatment of permanent conditions such as lazy eye.”

Red eye goes away with artificial tear treatment: False!

In conjunctivitis, one of the most common eye diseases in Turkey and popularly known as ‘red eye’, using only artificial tears or drops that have benefited others can cause serious problems. Assoc. Prof. Dr. Özge Begüm Comba warned that if this disease is not treated on time, visual defects and vision loss may develop, “Conjunctivitis is inflammation of the membrane covering the inside of the eyelid and the most common source is viral and bacteria. It is of great importance that this picture is evaluated by a physician and the treatment is carried out in accordance with the causative agent. Otherwise, conjunctivitis may cause spots that may cause vision loss.”

It is Not Possible to Stop Eye Number: False!

The most important factors in the progression of eye number are genetic and environmental factors. In the light of scientific studies; limiting close work, resting the eyes by looking away for 20 seconds every 20 minutes and outdoor activities for at least 2 hours a day are recommended. In addition, until the age of 18, it is possible to stop the progression of the eye number thanks to drops that enlarge the pupil, special lenses and lenses that are used at night and shape the cornea.

Do Not Have Children Have an Eye Checkup If There Are No Symptoms: False!

Early diagnosis and treatment of serious problems such as cataracts and eye tumors are both visually and vitally important. Assoc. Prof. Dr. Özge Begüm Comba said, “In addition, conditions such as lazy eye and strabismus may not be noticed by parents because they occur in one eye. In such diseases, it is very important to perform eye examinations in children at regular intervals starting from the first 2 months after birth, especially since there is a race against time.”

Cataract can be treated with drops: False!

Ophthalmologist Assoc. Prof. Dr. Özge Begüm Comba stated that the only known treatment method of cataract is surgery and continued as follows: “The intraocular lens that has aged and lost its transparency should be surgically removed and replaced with an artificial lens. However, of course, the progression of cataracts can be slowed down by reducing oxidative stress with methods such as healthy nutrition, regular blood sugar monitoring, and the use of sunglasses with UV blockage.”

Cataract is only seen in the elderly: False!

Although cataracts mostly develop in older people, they can also occur in childhood and infancy. Congenital cataracts can accompany various syndromes and can also be caused by infections in the womb and drug use. In childhood, it can also occur due to medications such as cortisone or accompany other diseases.

Eye pressure often causes eye pain: False!

Eye pressure is an extremely insidious disease. While it can sometimes manifest itself with a pain behind the eye, it often does not cause any pain. Closed angle glaucoma, on the other hand, has a more severe course and can cause serious pain due to sudden high eye pressure. Ophthalmologist Assoc. Dr. Özge Begüm Comba warns that eye pressure should be evaluated with annual follow-ups after the age of 40.

Eye diseases can be treated with herbal methods: False!

Applying garlic and lemon to any lesion in the eye, such as a stye, cannot give results and can be extremely dangerous as it can lead to different infections. Assoc. Prof. Dr. Özge Begüm Comba says, “The most effective treatment method is to manage the process with the medications recommended by the physician, keeping warm dressing and eyelash hygiene at the forefront.”

There is no need to wear sunglasses in fall and winter: False!

The sun’s harmful ultraviolet rays reach the earth even in cloudy weather and are reflected from the shadows. In addition to harmful rays, wind can cause dry eyes. For this reason, it is of great importance to use sunglasses for your eye health not only in summer but in all seasons.

June 2024

Choroideremia (CHM) is a rare genetic eye disease that affects the retina, which is the area at the back of the eye that processes all we see into signals that are sent to the brain via the optic nerve.

Choroideremia is a rare genetic retinal disease, which causes blindness in males during middle age. We still have much to understand about how the biochemical defect causes the retinal-specific disease and if it has any hidden effects on the rest of the body. Recently, there have been suggestions that CHM patients may be at risk of higher blood cholesterol or fat levels, and this is under currently investigation as part of detailed natural history studies. CHM has been used as a prototype retinal degeneration for developing novel gene therapies and hence, has provided much hope for those affected with the disease but also patients with similar inherited retinal disorders. Choroideremia affects about 1 in 50,000 individuals and is caused by a genetic defect in one single gene called the CHM gene, which is located on the X-chromosome. Male patients manifest the severe blinding form of the disease and suffer from a progressive retinal degeneration with obliteration of the light sensing cells (photoreceptors), their support cells (the retinal pigment epithelium) and part of the blood supply to these retinal layers (the choroid). The healthy orange retina is lost and the pale white sclera (tough white coat of the eye) can be seen when you look into the eye. Females are carriers and largely unaffected, however they can develop mild symptoms of visual impairment, such as night blindness, in more in later stages of life.

Choroideremia is Genetic
Choroideremia is caused by mutations in the CHM gene. The condition is passed down in families by the X-linked pattern of inheritance. In this type of inheritance, the mutated gene for the disease is located on the X chromosome. Females have two X chromosomes and can carry the disease gene on one of their X chromosomes. Because they have a healthy version of the gene on their other X chromosome, carrier females are usually not affected by X-linked diseases. Males have only one X chromosome (paired with one Y chromosome) and are therefore genetically susceptible to X-linked diseases. Males with X-linked diseases pass their Y chromosome to their sons, and therefore will never pass an X-linked disease to their sons. Female carriers have a 50 percent chance (or 1 chance in 2) of passing the X-linked disease gene to their daughters, who become carriers, and a 50 percent chance of passing the gene to their sons, who are then affected by the disease.

How the CHM Gene Works
The CHM gene encodes a protein called Rab Escort Protein-1 (REP1). This protein works in all our cells by helping to shuttle other small proteins (called Rabs) to their correct destination so they can undertake their role, such as allowing nutrients to pass across cells and removal of waste products. If these small proteins cannot be transported to their correct location to fulfill their job, the cells can starve and waste products build up causing damage and cell death. Humans are fortunate to have a second copy of REP1 called Rab Escort Protein-2 (REP2), which works well to transport Rabs in all the cells of our body except for the retina. The photoreceptors and retinal pigment epithelium have a subset of Rab proteins that prefer to be escorted by REP1 over REP2. Therefore, in the presence of a defective CHM gene with lack of REP1, there is a buildup of Rabs that are not able to function appropriately, and this leads to a retinal-specific disease that causes blindness in an otherwise fit and healthy individual.

Choroideremia Symptoms and Disease Progression
As an X-linked disease, choroideremia occurs primarily in males. In childhood, night blindness is the most common first symptom. As the disease progresses, there is loss of peripheral vision or “tunnel vision” and later a loss of central vision. Progression of the disease continues throughout the individual’s life, although both the rate and the degree of visual loss can vary, even within the same family. In affected male patients, the first symptom of CHM is night blindness, which is most commonly noticed in early childhood from as early as five or six years of age. The disease continues to progress with loss of the peripheral field of vision, this occurs at a relative fast rate in late adolescence and into the early twenties, leaving the patient with only a small area of central “tunnel” vision. The rate of decline lessens but the retinal degeneration continues to progress slowly over the next few decades, patients lose depth perception, color perception and finally loss of central vision with complete blindness into their fifties and sixties. Both the rate of disease progression and the degree of visual loss are variable among those affected, even within the same family. Female carriers are usually unaffected, but some do experience symptoms of night blindness later in life with some patchy loss in vision. This occurs because despite women having two X-chromosomes, one is switched off in every cell to ensure the correct amount of gene product (protein) is being produced. This process is random, called X-inactivation or lyonization, and means if the healthy X-chromosome is inactivated, then the X-chromosome carrying the defective CHM gene will prevent normal function in that particular retinal cell leading to disease in a patchy distribution.

Disorders with Similar Symptoms
Symptoms of the following disorders can be similar to those of choroideremia. Comparisons may be useful for differential diagnosis: X linked retinitis pigmentosa (RP) is the most common inherited vision disorder that has similar symptoms to choroideremia. X linked RP is passed from a mother (who carries or has RP) to a son. In RP, the retina degenerates, vision decreases and can be lost. Symptoms include night blindness leading to progressive loss of peripheral vision, followed by tunnel vision. Night blindness is usually the first noticeable symptom, generally occurring during childhood. This is followed by tunnel vision (loss of peripheral vision). The extent and progression of symptoms is variable. An eye doctor can differentiate between RP and choroideremia with an eye exam. Gyrate atrophy of the choroid and retina is characterized by a circular degeneration in the choroid and retina of the eye. Because this eye disorder results from the accumulation of ornithine in the blood, a blood test can be used to help diagnose it. In general, patients with this eye condition as have other medical problems such as muscle weakness. Very rarely, a single genetic variant in the RPE65 gene can cause a dominantly inherited condition that affects the retinal pigment epithelium and looks like choroideremia. The key feature is the pattern of inheritance is not X-linked.

How to Diagnose Choroideremia
A diagnosis can be made by an ophthalmologist with a specialist interest in genetic eye disease. They will have the expertise to interpret the patient history, signs from the clinical examination and investigations such as electrophysiology, fundus autofluorescence and optical coherence tomography. But ultimately, a genetic test to screen the CHM gene for mutations is required to make a definitive diagnosis. There have been rare cases of patients with a retinal appearance similar to CHM, but upon genetic testing have shown mutations in different genes known to cause other retinal dystrophies, such as RPE65. Another genetic condition called gyrate atrophy, which is an inborn error of metabolism, displays similar clinical features to CHM. It is caused by mutations in the ornithine ketoacid aminotransferase (OAT) gene found on chromosome 10.Patients show an increase in plasma levels of ornithine, however, reduction of the amino acid arginine in the diet prevents disease progression. This highlights the need to see a specialist so that CHM can be diagnosed correctly.

 What are the Treatments Ooptions
There is currently no cure or effective treatment for CHM. Much research is underway to seek a viable and sustainable therapy and there are a number of promising gene-based approaches under development. Firstly, the use of a drug administered orally to patients, which has the ability to override a specific genetic mutation, called a nonsense mutation, has been used which introduces an abnormal stop signal into the CHM gene. Nonsense mutations account for over 30% of CHM.

May 2024