Multiple myeloma is a cancer originating in plasma cells, a type of white blood cell found in the bone marrow. These cells normally produce antibodies to fight infections. In multiple myeloma, plasma cells become abnormal and multiply uncontrollably, leading to various health issues.
Amyloidosis is a condition where abnormal proteins, known as amyloid, accumulate in tissues and organs throughout the body. This buildup can impair the proper functioning of affected organs. This article focuses on how these protein deposits specifically affect the eyes in the context of multiple myeloma.
The Link Between Multiple Myeloma and Amyloidosis
In multiple myeloma, abnormal plasma cells in the bone marrow produce faulty antibody components called light chains. These light chains misfold and aggregate, forming insoluble amyloid fibrils. These fibrils then deposit in various tissues and organs.
This type of amyloidosis, directly associated with abnormal light chains from plasma cells, is known as AL amyloidosis. It is a known complication that occurs in about 10-15% of multiple myeloma patients. The accumulation of these amyloid proteins can lead to organ damage and various symptoms, depending on the deposit location.
AL amyloidosis primarily involves the buildup of these abnormal light chains, which circulate in the bloodstream and deposit in organs. This differs from multiple myeloma, where the main problem is the rapid growth of abnormal plasma cells in the bone marrow. Patients may be diagnosed with both conditions simultaneously.
How Amyloidosis Impacts Eye Health
Amyloid deposits can affect nearly every part of the eye and its surrounding structures, leading to a range of symptoms. These symptoms are often progressive and can affect both eyes.
Amyloid can impact various ocular components:
Eyelids: Swelling, drooping (ptosis), or waxy/yellowish lesions may appear.
Conjunctiva: Nodules, hemorrhages, or dryness can develop.
Cornea: Opacities and reduced sensation may occur.
Vitreous: Floaters and other opacities, such as cobwebs or crystalline structures, can significantly impair vision.
Retina: Vascular abnormalities, hemorrhages, and exudates can cause vision impairment.
Optic Nerve: Neuropathy may lead to visual field defects and vision loss.
Extraocular Muscles: Infiltration can cause restrictive myopathy, resulting in double vision (diplopia) and limited eye movement.
Lacrimal Glands: Infiltration leads to symptoms of dry eyes.
Trabecular Meshwork: Accumulation of proteins can lead to increased intraocular pressure and glaucoma.
Diagnosing Eye Involvement
Diagnosing ocular amyloidosis involves a thorough evaluation of the eyes and the patient’s overall systemic health. A comprehensive eye examination by an ophthalmologist is a primary step. This includes a slit-lamp examination to assess anterior structures like the cornea and conjunctiva, and an ophthalmoscopy or fundus exam to view posterior structures, including the retina and optic nerve.
Imaging techniques provide further insights into amyloid deposition. Optical Coherence Tomography (OCT) evaluates the retina and optic nerve for abnormalities. Ultrasound or Magnetic Resonance Imaging (MRI) of the orbit may visualize deposits in surrounding tissues or extraocular muscles.
A definitive diagnosis often requires a biopsy of affected tissue. This may involve ocular tissue or systemic sites. Tissue samples are then stained with Congo Red dye, which causes amyloid deposits to show a characteristic apple-green birefringence under polarized light, confirming amyloid fibrils.
Since ocular symptoms can be the first indication of systemic amyloidosis or multiple myeloma, a comprehensive systemic workup is necessary. This includes blood tests, urine tests, and a bone marrow biopsy to identify the underlying plasma cell disorder or systemic amyloidosis.
Managing Eye Symptoms
Managing eye-related complications in multiple myeloma amyloidosis centers on treating the underlying systemic condition. The primary goal is to reduce the production of abnormal light chains. This often involves systemic treatments for multiple myeloma and AL amyloidosis, such as chemotherapy or stem cell transplantation.
Specific treatments for eye symptoms focus on providing relief and preserving vision. For dry eyes, artificial tears or gels can manage discomfort. Surgical interventions may be considered for severe issues like eyelid drooping (ptosis) or vitreous opacities that significantly impair vision. Vitrectomy, a surgical procedure to remove vitreous opacities, has shown consistent improvement in visual acuity.
If glaucoma develops, management strategies for glaucoma are implemented. For double vision, prisms can help, and eye muscle surgery may be explored. Regular monitoring by an ophthalmologist tracks symptom progression and adjusts management. A collaborative approach involving hematologists, oncologists, and ophthalmologists is beneficial for comprehensive patient care.