Leukemia is a group of cancers originating in blood-forming tissues, such as the bone marrow and lymphatic system. This disease leads to the uncontrolled production of abnormal white blood cells, which interfere with the body’s ability to produce healthy blood cells. As a systemic condition, leukemia can affect various organs and tissues throughout the body. The eyes, with their intricate network of blood vessels and delicate structures, are among the areas that can be affected. Understanding these potential ocular involvements is important for patients and caregivers.
Direct Ocular Infiltration by Leukemia Cells
Leukemia cells can directly invade and accumulate within various eye structures, a process known as ocular infiltration. This can disrupt normal eye function and lead to specific visual symptoms.
The retina, the light-sensitive tissue at the back of the eye, is a common site for infiltration. When leukemic cells accumulate here, they can cause blurry vision, dark spots or “floaters,” or even retinal detachments.
The optic nerve, which transmits visual information from the eye to the brain, is another vulnerable area. Infiltration of the nerve or its surrounding sheath can cause swelling and dysfunction. This may result in rapid vision loss in the affected eye, sometimes with pain when moving the eye.
The uvea, the middle layer of the eye (iris, ciliary body, and choroid), can also be directly infiltrated. Uveal infiltration may lead to inflammation, causing redness, pain, light sensitivity, and decreased vision. Leukemia cells can also form visible masses within the uveal tissue.
Beyond the eyeball, the orbital tissues surrounding the eye can experience direct leukemic infiltration. This may manifest as proptosis, where the eyeball protrudes forward due to cell accumulation behind it. Orbital infiltration can also cause swelling, pain, and restricted eye movement.
Indirect Ocular Complications from Leukemia
Beyond direct cellular invasion, the systemic effects of leukemia on blood components can indirectly cause various ocular complications.
Anemia, a reduced number of healthy red blood cells, is a common complication. In the eyes, severe anemia can manifest as pallor of the conjunctiva, the clear membrane lining the inside of the eyelids.
Thrombocytopenia, a reduction in platelets, is another indirect complication. Platelets are essential for blood clotting, and their deficiency increases the risk of bleeding, including in the eyes. This can lead to spontaneous hemorrhages on the eye’s surface or within the retina, potentially impairing vision.
A high burden of leukemia cells can also lead to hyperviscosity syndrome, where the blood becomes abnormally thick. This impairs blood flow, especially in the retina’s small vessels. Sluggish circulation can result in venous engorgement, microaneurysms, hemorrhages, and vessel blockages. These impairments can cause blurry vision, vision loss, or cotton wool spots.
Ocular Side Effects of Leukemia Treatment
Leukemia treatments, while aiming to eradicate cancer cells, can also lead to various side effects affecting the eyes.
Chemotherapy often causes dry eye syndrome due to its impact on tear production. Patients may experience irritation, a gritty sensation, redness, and blurred vision. Chemotherapy can also suppress the immune system, increasing the risk of ocular infections like conjunctivitis.
Radiation therapy poses specific risks to ocular health. Radiation can damage retinal blood vessels and nerve fibers, leading to radiation retinopathy. This may cause progressive vision loss, retinal hemorrhages, and macular edema. Radiation to the eye or surrounding structures can also accelerate cataract development and induce persistent dry eye syndrome.
Stem cell transplantation can lead to ocular Graft-versus-Host Disease (GVHD). This occurs when donor immune cells attack the recipient’s eye tissues. Ocular GVHD often results in painful dry eyes, inflammation of the conjunctiva, cornea, and eyelids, and can lead to vision impairment.
Diagnosis and Management of Eye-Related Issues
Any new or worsening eye or vision symptom in an individual with leukemia warrants immediate medical evaluation. Early detection of ocular involvement can influence treatment strategies and help preserve vision. The diagnostic process typically begins with a comprehensive, dilated eye examination by an ophthalmologist. During this exam, the ophthalmologist inspects the retina, optic nerve, and other structures for signs of infiltration or hemorrhage.
Specialized imaging techniques may also be used. Ocular ultrasound can provide images of internal eye structures. Magnetic Resonance Imaging (MRI) of the brain and orbits may be performed to assess for optic nerve involvement, orbital masses, or central nervous system spread of leukemia.
The primary approach to managing eye-related issues is to treat the underlying cancer. Bringing leukemia into remission often improves or resolves ocular manifestations. In addition to systemic leukemia treatment, specific ocular therapies may be employed to manage symptoms and prevent further damage. For example, steroid eye drops can reduce inflammation. Localized radiation therapy may be considered for localized leukemic masses. Effective management requires close collaboration between the patient’s oncology team and ophthalmology specialists.