Amyloidosis can indeed be found in the eye according to Dr. Chafic Karam, professor of neurology from the University of Pennsylvania. In addition, while most of the transthyretin protein originates in the liver, local production is found in other areas of the body such as the brain and retina.
AMYLOIDOSIS
Amyloidosis is a rare disease that happens when abnormal transthyretin proteins called amyloid build up in different parts of the body, including the eye and surrounding areas.
Some people develop localized amyloidosis, meaning the protein buildup only affects the eye. Others have systemic amyloidosis, where amyloid deposits form in multiple organs, including the kidneys and heart. Systemic amyloidosis can increase the risk of kidney damage and heart failure.
HOW AMYLOIDOSIS CAN AFFECT THE EYE
Amyloidosis can affect multiple structures of the eye including the eyelids, cornea, retina, and the gel-like substance inside the eye, with symptoms such as droopy eyelids, vision changes, and dry eyes, while certain types of amyloidosis are more likely to affect specific parts of the eye. Ocular amyloidosis (amyloidosis in the eye) can cause symptoms that range from mild discomfort to serious vision problems.
Symptoms can include:
- Lumps under the skin
- Ptosis (a droopy eyelid)
- Diplopia (double vision)
- Constant eye irritation, which may feel like dryness
- Blurred vision or seeing “floaters,” cobwebs, or sheets
- Globally displaced or protruded eye
- Purpura (purple or blue skin) surrounding the eyes, which may appear or worsen when you touch or rub your eyes
AMYLOIDOSIS IN THE EYELIDS, ORBIT, AND CONNECTIVE TISSUE OF THE EYE
Amyloid proteins can build up in the outer parts of the eye, including the eyelid skin, the orbit (the bones that form the eye socket), and the connective tissues that help the eyes move.
AMYLOIDOSIS IN THE CONJUNCTIVA
The conjunctiva is a thin, moist membrane that lines the inside of the eyelids and covers the white part of the eye. In some cases, amyloid proteins may be deposited in this membrane, leading to conjunctival amyloidosis.
Conjunctival amyloidosis usually appears as a small, yellow, waxy mass on the eye. It can occur in both AL amyloidosis and AA amyloidosis. Some people with conjunctival amyloidosis have other amyloidosis-related symptoms in the body, while others do not.
A specific type of amyloidosis, called hereditary amyloidosis (familial amyloidosis), is strongly linked to amyloidosis in the conjunctiva. Hereditary transthyretin (TTR) amyloidosis (hATTR amyloidosis) happens when the liver makes an abnormal form of the TTR protein, which can lead to amyloid buildup in various organs, including the eyes. Since hATTR amyloidosis runs in families, people with a family history should be aware of potential symptoms.
One small-scale study found that among 37 people with hATTR amyloidosis, 75 percent developed abnormal blood vessels in the conjunctiva. This eye problem can lead to severe vision loss, especially if not identified and treated early.
AMYLOIDOSIS IN THE CORNEA
The cornea is the clear, dome-shaped layer over the iris (colored part of the eye). It helps focus light into the eye, allowing you to see clearly. Amyloidosis can affect the cornea in several ways.
Gelatinous Drop-Like Corneal Dystrophy
A hereditary form of amyloidosis can cause gelatinous drop-like corneal dystrophy, a condition where amyloid proteins build up on the cornea. This buildup makes it harder to see and can cause vision problems over time.
Lattice Stromal Dystrophies
Amyloid proteins can also lead to lattice stromal dystrophies, where branching, white lines form inside the cornea. People with this condition may notice white dots and a hazy appearance in the cornea. These dystrophies are caused by specific genetic mutations (changes) linked to amyloidosis.
Keratoconjunctivitis Sicca and Corneal Neuropathy
Hereditary TTR amyloidosis is often associated with corneal neuropathy (loss of corneal sensitivity), which is important for blinking and eye protection. It can also lead to corneal ulcers (open sores on the cornea). Amyloid deposits in the cornea may cause a disease called keratoconjunctivitis sicca (KCS), also known as dry eye disease. KCS can cause severe corneal dryness, which may lead to damage if untreated.
AMYLOIDOSIS IN THE IRIS OR LENS
When amyloidosis affects the iris or lens, it can lead to glaucoma, a group of eye diseases that damage the optic nerve, which carries signals from the eye to the brain. This damage can cause vision loss. Types of glaucoma linked to amyloidosis include rubeotic glaucoma and particle/particulate glaucoma.
Amyloidosis can also cause a condition called scalloped pupils. In this condition, the border between the iris (the colored part of the eye) and the pupil is uneven, giving the pupil a wavy or scalloped appearance. This happens when amyloid deposits build up around the pupil, pushing it out of shape. In some cases, scalloped pupils can be a sign of systemic (whole-body) amyloidosis.
Hereditary amyloidosis is the most common cause of amyloidosis in the iris or lens. Specifically, familial amyloidosis is strongly linked to chronic open-angle glaucoma, a condition that slowly increases pressure inside the eye, leading to vision loss over time.
Additionally, people with hATTR amyloidosis often develop more cataracts and far-sightedness earlier than usual.
AMYLOIDOSIS IN THE RETINA OR VITREOUS
The vitreous is the gel-like substance that fills much of the inside of the eye. When amyloidosis affects the vitreous, it produces opaque (cloudy) areas in the gel that can look like cobwebs, sheets, or pearls. The severity of vision problems depends on how dense the amyloid deposits are.
The retina is the light-sensitive membrane at the back of the eye that helps the brain process images. Amyloid proteins in the retina can change how the eye detects light. This can lead to discolorations in the retina or distortion of its shape.
Amyloidosis in the retina or the vitreous is usually caused by hereditary amyloidosis. About 20 percent of people with hATTR have hemorrhages and cotton wool spots (fluffy white patches of retinal damage) on eye exams, which are signs of retinal and vitreous disease. Retinal amyloidosis may also occasionally occur in primary amyloidosis that affects the whole body.
AMYLOIDOSIS AND OCULAR INVOLVEMENT FROM AN EXPERT
Dr. Chafic Karam, professor of neurology from the University of Pennsylvania, provides an informative overview of how certain mutations of transthyretin amyloidosis are being diagnosed in the central nervous system (CNS), which includes the eye. Starting at 8:15 in the video below, Dr. Karam discusses ocular involvement with amyloidosis – symptoms, how and where the eye can be impacted, and treatment considerations. With patients living longer due to successful amyloidosis therapies now available, he predicts neurologists will see more and more patients with CNS complications and ocular involvement.
Sources
https://www.myamyloidosisteam.com/resources/does-amyloidosis-affect-the-eyes
Ocular Manifestations of Systemic Amyloidosis
Reynolds MM, Veverka KK, Gertz MA, Dispenzieri A, Zeldenrust SR, Leung N, Pulido JS. OCULAR MANIFESTATIONS OF SYSTEMIC AMYLOIDOSIS. Retina. 2018 Jul;38(7):1371-1376. doi: 10.1097/IAE.0000000000001901. PMID: 29068915.
Amyloidosis and Ocular Involvement: an Overview
Dammacco R, Merlini G, Lisch W, Kivelä TT, Giancipoli E, Vacca A, Dammacco F. Amyloidosis and Ocular Involvement: an Overview. Semin Ophthalmol. 2020 Jan 2;35(1):7-26. doi: 10.1080/08820538.2019.1687738. Epub 2019 Dec 12. PMID: 31829761.
Ocular Amyloidosis
