Eye changes may signal cancer, diabetes and high blood pressure

Your eyes are more than just organs of vision; they are often the first place your body detects warning signs of serious health problems. Ophthalmologists emphasize that conditions such as diabetes, high blood pressure, high cholesterol, and even some cancers can be detected early through a comprehensive eye exam.

These changes are often invisible to the patient but can be detected by trained professionals using advanced imaging tools. Early detection of these signs allows for timely intervention, protecting both vision and overall health, and sometimes even saving lives.

The eyes are a unique window into the body's overall health. A 2024 review in Frontiers in Medicine notes that many systemic diseases, from diabetes and hypertension to cholesterol disorders, autoimmune diseases, and cancer, often show subtle signs in the eyes before other symptoms appear. For example, retinal blood vessels can detect vascular problems early because they can be directly observed, unlike most internal blood vessels.

Ophthalmologists trained to recognize retinal narrowing, deposits, or abnormal pigmentation are often the first to detect this risk. Therefore, regular eye exams provide important early warning signals, supporting more comprehensive disease prevention and management.

Diabetes: detected many years before other symptoms appear

Diabetes is often called the silent disease because it can damage organs and tissues long before symptoms appear. According to the National Eye Institute, diabetic retinopathy is one of the earliest complications that can be detected. High blood sugar damages the small blood vessels in the retina, causing swelling, leakage, or abnormal blood vessel growth.

Early detection through regular eye screening is essential, especially for people with risk factors such as obesity or a family history of diabetes. Timely intervention can prevent vision loss and reduce the risk of serious complications associated with persistently high blood sugar.

High blood pressure and high cholesterol are visible to the naked eye.

High blood pressure and high cholesterol often develop silently, causing serious health risks without obvious symptoms. However, the eyes can show early signs before complications arise. Hypertensive retinopathy, caused by long-term high blood pressure, damages the small blood vessels in the retina, causing them to narrow, thicken, or bleed.

Similarly, high cholesterol can manifest as yellow plaques on the eyelids (xanthelasma) or cholesterol plaques inside the retinal blood vessels, called Hollenhorst plaques.

Cancer and neurological diseases can also be detected.

The eyes can also provide early warning signs for certain cancers and neurological disorders. Eye cancers , such as retinoblastoma or ocular melanoma, may initially appear as abnormal pigment changes or lesions in the retina. Additionally, systemic cancers sometimes metastasize to the eye, and subtle retinal pigment abnormalities, such as bear-paw patterns, have been associated with colon cancer.

Neurological problems, including multiple sclerosis and brain tumors, can cause early symptoms such as double vision, uneven pupil reactions or sudden difficulty reading. Research shows that visual field testing and detailed eye exams can identify these problems before patients notice specific symptoms, highlighting the important role of the eye in early detection.

Glaucoma and other silent threats caught early

Glaucoma, often called the silent thief of sight, progresses without obvious symptoms until irreversible vision loss occurs. It develops when intraocular pressure increases, damaging the optic nerve. A 2019 study noted that systemic factors such as age, high blood pressure, and high cholesterol can increase the risk of glaucoma. Normotensive glaucoma, when eye pressure remains normal, can be caused by low blood pressure or conditions such as sleep apnea. Early detection through an eye exam, which includes an evaluation of the optic nerve and pressure measurement, allows for prompt treatment, often preventing permanent vision loss. This reinforces why glaucoma screening is an important part of regular eye care.

Marvin Fry

Update 21 August 2025