Rare diseases, as defined by WHO, typically impacting less than 200,000 individuals, and many of these affect eye health.

AEVR recently hosted a congressional briefing to highlight lesser-known diseases that cause vision loss and blindness, including those from its member Foundation Fighting Blindness. Ben Shaberman from Foundation Fighting Blindness discussed research advances related to various rare retinal degenerative disorders.

Retinitis Pigmentosa

Retinitis Pigmentosa (RP) is a group of genetic conditions that alter how the retina, the thin layer that covers the back wall of the eye, responds to light. Composed of photosensitive cells called rods and cones that convert light signals into visual images recognized by our brain, it works through gradual loss of vision due to rods and cones being activated, leading to gradual loss. Retinitis pigmentosa causes gradual vision loss which makes night vision hard or dim lighting conditions challenging; peripheral (side vision), eventually diminish peripheral (side vision), tunnel vision becomes reality over time – mutations caused by genes responsible for controlling traits passed from parent to child over generations of time. RP causes gradual loss caused by mutations of genes controlling traits passed from parent to child over generations of time which pass from parent-child.

Retinitis pigmentosa symptoms appear gradually over time, typically during childhood or adolescence. Over time, people with this disease lose the ability to see in low light conditions and may eventually become legally blind. Though both eyes can be affected, males typically exhibit more severe symptoms because the gene that controls retinitis pigmentosa can only be found on one X chromosome; female inheritors who inherit mutant genes may experience less severe effects as their second normal X chromosome counterbalances negative effects of having two normal ones to balance out effects caused by one mutant gene that controls it.

Current treatments cannot reverse retinal damage or restore lost vision; however, vitamin A palmitate and supplements lutein and zeaxanthin may help slow progression in some individuals, while carbonic anhydrase inhibitors are available for treating swelling of the retina (macular edema) that often occurs with late stages of retinitis pigmentosa. A novel gene therapy approach that works like a virus may restore some vision for some with certain forms of this condition.

Ocular drug development is a complex endeavor and requires an in-depth knowledge of disease progression. Selecting biomarkers and surrogate endpoints as key success metrics of clinical trials is important in meeting regulatory standards; rare disease registries also provide vital data which may speed the translation of basic research to clinical practice more rapidly.

Nevi

Nevi are visible, circumscribed vascular lesions that may form at birth or later in life. Although usually harmless, they have been linked with retinal detachment, cataracts and glaucoma as well as being risk factors for skin cancer. Nevi can’t be classified into two groups – non-neoplastic and neoplastic lesions – thus experts generally accept that this term encompasses both benign and malignant lesions.

Nevus may not be as prevalent as age-related macular degeneration or diabetic retinopathy, yet they still impact many. Nevus are one of the leading causes of blindness among children and young adults and often present themselves with multiple symptoms making diagnosis challenging.

Patients living with rare eye diseases are frequently subjected to misdiagnosis, treatment disparities and social isolation which can negatively impact quality of life and access to healthcare. Therefore it is crucial that doctors can recognize these disorders early so as to minimize their impact on patients and their families.

The European Reference Network for Rare Eye Diseases (ERN-EYE) is working towards creating a database of rare eye diseases to enable better diagnostic methods, which in turn will enhance patient outcomes and facilitate clinical research projects.

Rare diseases are conditions affecting fewer than 200,000 Americans and there are over 7,000 that affect eyes alone, though most remain underdiagnosed and unnoticed. While they may not receive as much public attention as conditions such as macular degeneration and diabetic retinopathy, rare eye diseases still pose significant risks of vision loss or blindness.

Multiple diseases have genetic roots; mutations of specific genes cause them. Therefore, genetic testing can be an invaluable resource in diagnosing these disorders; unfortunately though it isn’t yet widely accessible across all nations.

On May 25th, AEVR held its inaugural Congressional Briefing which focused on lesser-known eye diseases that lead to vision loss and blindness. Ben Shaberman from Foundation Fighting Blindness discussed recent advancements regarding retinal disease and Thyroid Eye Disease – two conditions which can contribute to blindness.

Bietti’s Crystalline Dystrophy

Bietti’s Crystalline Dystrophy is an autosomal recessive condition in which yellow-white crystalline lipid deposits accumulate within the light-sensitive retina lining the back of the eye, leading to progressive vision loss due to chorioretinal atrophy and reduced light sensitivity. People affected by Bietti’s Crystalline Dystrophy typically begin experiencing symptoms in their teens or early twenties and notice their sharp, clear vision diminishing gradually – they may experience difficulty with dim lighting (night blindness) as well as loss in side or peripheral vision which makes daily activities challenging or impossible altogether by their third decade of life; legal blindness typically ensues by this point.

Individuals affected by tapetoretinal degeneration typically show a characteristic glittering appearance of multiple small, finely distributed, translucent dots in the macula and yellow sheen in their retinal pigment epithelium (RPE), along with yellow sheening of RPE. Glittering deposits may diminish or disappear altogether in areas of severe chorioretinal atrophy; SD-OCT shows diffuse thinning of outer retina, RPE and choriocapillaris in both eyes; this similar to what can be observed in other forms of tapetoretinal degeneration such as Leber congenital amaurosis or Retinitis pigmentosa.

Disease is caused by mutations to the CYP4V2 gene, which encodes for an enzyme in the cytochrome P450 family known as P450s that perform various oxidative metabolic reactions. As yet undefined are its specificity and physiological role(s).

Typically, one mutation in the CYP4V2 gene is associated with RPE cancer; however, multiple mutations have been identified and no correlation between genotype and phenotype has been established. Mutations could alter protein activity leading to decreased RPE metabolism of essential long-chain fatty acids.

At late stages of Bietti’s crystalline dystrophy, patients develop hypofluorescent areas in the retina (Figure 2). These are caused by increased accumulation of complex lipid inclusions within RPE cells adjacent to regions of atrophy. Other changes include reduced rod and cone photoreceptor responses on ffERG/mfERG tests as well as loss of color vision; unfortunately these symptoms cannot be reversed and it is therefore vital that early diagnosis be made to avoid serious vision loss.

Bell’s Palsy

Bell’s palsy is an uncommon condition affecting the seventh cranial nerve (also known as facial nerve), and typically results in weakness or paralysis on one side of the face. This damage usually occurs where it passes through bones in the skull and causes nerves to be affected; most commonly seen among older adults but also possible at any age; commonly found among pregnant women and those living with diabetes as well as people with impaired immunity such as Lyme disease, Sarcoidosis shingles chickenpox herpes simplex virus type 1 and 2.

Bell’s palsy symptoms often develop quickly and tend to be more severe on one side of the face than the other, reaching peak severity within 48-72 hours. Seeking medical assistance quickly is highly advised as this condition resembles stroke symptoms and could potentially become life-threatening.

Bell’s Palsy can cause mild weakness to full paralysis of facial muscles, typically on one side of the face but potentially both sides at once. Other symptoms may include loss of taste or difficulty speaking/eating.

If you suffer from eye irritation, it is vitally important that your eye remains moist and protected with lubricating drops or ointments. In extreme cases, wearing an eye patch may be necessary; be cautious when washing hair or applying cosmetics; additionally it’s vitally important that the sun doesn’t reach your eye as this can exacerbate its irritation further.

There is no cure for Bell’s palsy, but certain steroid medications may help improve recovery chances. Examples include prednisolone and acyclovir; usually this condition resolves itself on its own over time but in certain instances longer-term care may be required with antiviral medication to accelerate healing processes.