Eye Lesions: Types, Causes, and When to See a Doctor

Eye lesions span a remarkably wide range, from tiny, harmless bumps on the eyelid to pigmented spots inside the eye that demand immediate treatment. In a large study of nearly 8,000 surgically removed eye masses, roughly two-thirds originated on the eyelid, about a fifth on the eye’s surface, and another fifth in the orbit behind the eye, with the vast majority turning out to be benign. Still, the minority that are malignant can threaten both vision and life, and distinguishing one from the other based on appearance alone is notoriously difficult. Understanding where eye lesions tend to show up, what causes them, and which features should prompt a visit to an ophthalmologist can make that distinction far less anxiety-inducing.

Eyelid Lesions Are the Most Common

Your eyelids are the single most frequent site for eye-related growths. In a clinicopathological review of 7,910 ocular mass lesions, eyelid cases accounted for nearly 63% of the total. Among benign eyelid masses, pigmented nevi (moles) were the most common, followed by squamous cell papillomas and seborrheic keratoses. When eyelid masses did turn out to be malignant, basal cell carcinoma led the way at roughly half of all malignant eyelid cases, followed by sebaceous gland carcinoma and squamous cell carcinoma.¹

Basal cell carcinoma of the eyelid looks and behaves much like it does elsewhere on the face: it tends to grow slowly, rarely spreads to distant organs, and usually appears as a pearly or waxy bump, often on the lower lid where sun exposure is greatest. It is the least dangerous of the three major eyelid cancers, but it can erode deeply into surrounding tissue if left alone.

Sebaceous gland carcinoma deserves special attention because it is a master of disguise. It arises from the oil-producing glands in the eyelid and frequently mimics benign conditions like chalazia (stye-like bumps) or chronic blepharitis (eyelid inflammation). That talent for mimicry leads to high rates of misdiagnosis. In one review, discrete foci of sebaceous carcinoma were initially misdiagnosed about 80% of the time, with simultaneous involvement of both upper and lower eyelids in a similar proportion of cases.² A case report documented a patient whose sebaceous gland carcinoma was mistaken for basal cell carcinoma for nine years before the correct diagnosis was made, by which point the cancer had already spread to lymph nodes.³ The takeaway is that any eyelid lump that keeps coming back after treatment, or that does not follow the expected course of a benign condition, warrants a biopsy rather than another round of warm compresses.

Lesions on the Eye’s Surface

The conjunctiva, the clear membrane covering the white of the eye, and the cornea, the transparent front window, are both vulnerable to growths, infections, and degenerative changes.

Conjunctival Growths

Among benign conjunctival masses, pigmented nevi again top the list, followed by papillomas. When malignancy does occur on the ocular surface, lymphoma and squamous cell carcinoma are the main culprits.¹ A conjunctival nevus typically appears in childhood or young adulthood as a flat or slightly raised brown spot, often containing small cysts that give it a characteristic “Swiss cheese” appearance. Cysts inside a pigmented conjunctival spot are actually a reassuring sign: in children, nevi with cysts were far more common than melanomas with cysts.⁴

Conjunctival melanoma is uncommon but serious. Compared to benign nevi, melanomas in adults tend to show up later in life, are thicker, have a larger base, more often display feeder blood vessels running to the lesion, and are more likely to bleed.⁵ A flat, brownish discoloration spreading across the conjunctiva without a clear raised mass can be a precursor condition called primary acquired melanosis. Differentiating that precursor from early melanoma can be challenging even for specialists, because both may look like diffuse pigmentation, but melanoma tends to have greater thickness, more prominent blood vessels, and occasionally hemorrhage.

Pterygium, a fleshy triangular growth that extends from the white of the eye onto the cornea, is one of the most common benign surface lesions worldwide. It is strongly associated with chronic ultraviolet radiation exposure, though other sources of chronic inflammation may also contribute.⁶ Pterygia are not cancerous and rarely threaten vision unless they grow far enough across the cornea to block the visual axis. They are most prevalent in people who spend long hours outdoors in equatorial or high-UV environments.

Corneal Lesions

Unlike the conjunctiva, the cornea does not commonly develop tumors. Its lesions are more often infectious or inflammatory. Microbial keratitis, an infection of the cornea, is one of the most urgent eye conditions because it can scar the cornea and permanently reduce vision within days. Contact lens wear is a major risk factor, with bacterial infections being the most common cause, though fungi and Acanthamoeba can also be responsible.⁷ Overnight lens wear is especially risky.⁸

Herpes simplex keratitis is another important corneal lesion. The same virus that causes cold sores can infect the cornea, triggering pain and a cascade of inflammation that, over repeated episodes, leads to corneal clouding, new blood vessel growth into the normally clear cornea, and loss of corneal nerve function.⁹ Because it tends to recur, herpes keratitis is one of the leading infectious causes of corneal blindness in developed countries.

Lesions Inside the Eye

Growths that form inside the eye, particularly in the uveal tract (the iris, ciliary body, and choroid), are invisible from the outside and usually discovered during a dilated eye exam. The choroid, the blood-vessel-rich layer behind the retina, is where the most common intraocular tumor in adults develops: choroidal melanoma.

Most pigmented spots found in the choroid are nevi, which are essentially freckles of the eye’s interior. The challenge lies in figuring out which ones will stay benign and which might transform into melanoma. A helpful clinical framework uses the mnemonic TFSOM: thickness greater than 2 mm, subretinal fluid, symptoms such as blurred vision or flashing lights, orange pigment overlying the spot, and margin touching the optic disc. A choroidal pigmented spot with none of these features has roughly a 3% chance of growing into melanoma over five years. One feature pushes that risk to about 38%, and two or more features mean growth occurs in over half of cases, strongly suggesting the spot already is a small melanoma.¹⁰ This is why ophthalmologists photograph and measure choroidal spots at regular intervals rather than immediately treating every one.

Not all intraocular lesions are tumors. Lisch nodules, small dome-shaped bumps on the iris, are a hallmark of neurofibromatosis type 1, a genetic condition. In one study, these nodules appeared in 73% of patients with neurofibromatosis, and their presence correlated with disease severity.¹¹ They do not threaten vision themselves, but their discovery during a routine eye exam can be the first clue to a systemic genetic disorder.

Retinal Findings That Point Beyond the Eye

The retina acts as a window into the body’s vascular and metabolic health, which is why eye exams can pick up signs of diseases that have nothing to do with the eyes per se.

Cotton-wool spots are fluffy white patches on the retina caused by interrupted blood flow to small retinal arterioles. They represent debris building up at the level of retinal nerve fiber cells when normal axonal transport is blocked.¹² Though occasionally isolated and harmless, cotton-wool spots more often signal underlying hypertension, diabetes, or autoimmune disease. Finding even one during a routine exam usually triggers blood pressure checks, blood sugar testing, and sometimes a workup for conditions like lupus or HIV.

Congenital hypertrophy of the retinal pigment epithelium (CHRPE) offers a striking example of how a retinal finding can affect medical decisions far from the eye. Typical CHRPE lesions are flat, dark, well-defined spots that are usually discovered incidentally and are harmless on their own. However, atypical CHRPE, characterized by multiple bilateral lesions, is strongly linked to familial adenomatous polyposis, a genetic condition that causes hundreds of colon polyps and carries a near-certain risk of colorectal cancer by middle age if untreated.¹³ Genetic studies have confirmed that CHRPE is a direct manifestation of the same gene mutation, making it a useful early marker for identifying family members who carry the mutation.¹⁴ In families with known polyposis syndromes, eye exams serve double duty as cancer screening.

When Eye Lesions Signal Systemic Disease

Several systemic diseases announce themselves through eye lesions. Sarcoidosis, an inflammatory condition that most commonly affects the lungs, presents with eye involvement in roughly 20 to 30% of patients. The most frequent ocular signs are a type of uveitis (inflammation inside the eye) with characteristic granulomatous deposits, dry eye, and small nodules on the conjunctiva.¹⁵ Because eye symptoms sometimes appear before lung or skin symptoms, an ophthalmologist may be the first clinician to suspect sarcoidosis.

Diabetes is another systemic condition intimately connected to eye lesions. Diabetic retinopathy produces a recognizable pattern of microaneurysms, hemorrhages, and hard exudates on the retina. Advanced stages can involve abnormal new blood vessel growth that bleeds into the vitreous cavity. Routine retinal screening in people with diabetes catches these changes early, before they cause noticeable vision loss.

Warning Signs That Call for Prompt Evaluation

Not every spot or bump on or around the eye requires an emergency visit, but certain features should move you to see an eye doctor sooner rather than later. The following are red flags worth knowing:

Rapid growth: Any mass on the eyelid, conjunctiva, or inside the eye that enlarges noticeably over weeks to months, rather than staying stable for years.
Bleeding: Hemorrhage on or around a conjunctival lesion is a feature that distinguishes melanoma from benign nevi in both adults and children.⁴
Visible feeder vessels: Prominent blood vessels feeding into a conjunctival or ocular surface lesion suggest a more aggressive process.⁵
New visual symptoms: Flashing lights, a shadow or curtain in part of your vision, or sudden blurring in one eye can indicate retinal involvement from an intraocular lesion.
Eyelid lump that recurs after treatment: A chalazion or stye that keeps coming back in the same spot may actually be sebaceous gland carcinoma masquerading as a benign condition.¹⁶
Loss of eyelashes: Localized lash loss over a bump can signal a malignant process eroding the hair follicles.
White pupil reflex in a child: A white glow in a child’s pupil, sometimes noticed in flash photographs, can be a sign of retinoblastoma and requires urgent referral.

If you are unsure whether a finding is urgent, a reasonable rule of thumb is that any new or changing lesion visible to the naked eye, or any unexplained change in vision, is worth at least one visit to an ophthalmologist rather than a wait-and-see approach at home.

How Eye Lesions Are Diagnosed

The first-line tool is the slit-lamp examination, a specialized microscope that gives the ophthalmologist a magnified, illuminated view of the eyelids, conjunctiva, cornea, iris, and lens. For structures at the back of the eye, a dilated fundus exam using lenses and a bright light source reveals the retina, choroid, and optic nerve.

Optical coherence tomography (OCT) has become an increasingly important complement to clinical examination. This imaging technique creates cross-sectional views of eye tissue at near-microscopic resolution. Slit-lamp-adapted OCT allows precise measurement of structures in the front of the eye.¹⁷ For surface lesions, ultra-high-resolution OCT has proven particularly valuable when the clinical picture is ambiguous. In a study of ocular surface lesions, OCT images showed close correlation with biopsy results and, in several cases involving conditions like amelanotic melanoma and squamous neoplasia, the OCT scan suggested the initial clinical diagnosis was wrong before histopathology confirmed it.¹⁸ A more recent study using swept-source OCT found that in about a third of cases where the clinical suspicion differed from the final biopsy result, the OCT images had pointed toward the correct diagnosis.¹⁹

Despite these advances, biopsy remains the gold standard whenever malignancy is a possibility. OCT and clinical examination guide the decision about whether, when, and where to biopsy, but a tissue sample under the microscope is still the definitive way to confirm or rule out cancer.

Eye Lesions in Children

Pediatric eye lesions overlap with adult types in some ways but have their own distinct priorities. The most feared pediatric intraocular tumor is retinoblastoma, a cancer of the developing retina that almost exclusively affects young children. The classic presenting sign is leukocoria, a white pupillary reflex sometimes captured in photographs when flash catches the tumor instead of the normal red reflex. In a large screening study, leukocoria was associated with excellent patient survival (over 86% at five years) but poor eye survival, meaning the eye often could not be saved by the time the tumor was large enough to produce a visible white reflex.²⁰ Children with a family history of retinoblastoma who were screened from birth were diagnosed younger, at earlier tumor stages, and had better outcomes for preserving the eye.

Red-reflex testing, in which a clinician shines an ophthalmoscope into both eyes simultaneously to check for a symmetric red glow, is the standard screening method built into routine pediatric well-child visits. Research suggests the sensitivity of this test improves with oblique viewing angles and pharmacologic pupil dilation.²¹ Parents who notice a white or yellow reflex in photographs of their child should bring it to a pediatrician’s attention promptly, as roughly 80% of retinoblastoma cases in one large series were initially spotted by a family member or friend rather than by a clinician.

For conjunctival lesions in children, most are benign nevi. The same features that differentiate benign from malignant in adults apply, though conjunctival melanoma in children is rare. When it does occur, it tends to present in older adolescents (between 15 and 21) and shows the same warning signs of greater thickness, larger size, hemorrhage, and absence of intrinsic cysts.⁴

UV Protection and Prevention

Ultraviolet radiation is a common thread running through several types of eye lesions, from pterygia and pingueculae on the surface to eyelid skin cancers. Simple behavioral measures go a long way: wearing UV-blocking sunglasses or spectacles, broad-brimmed hats, and avoiding prolonged midday sun exposure all reduce cumulative UV dose to the eyes.²² Wraparound-style sunglasses are preferable to standard frames because they block light entering from the sides, which standard lenses miss.

The importance of UV protection is dramatically illustrated by xeroderma pigmentosum, a rare genetic condition in which the body cannot repair UV-induced DNA damage. People with this condition develop a wide spectrum of eye problems, including surface tumors and corneal disease, at very young ages. Strict sun protection, including fully shielding eyewear, is essential for these patients.²³ While xeroderma pigmentosum is extreme, it underscores a principle that applies to everyone: the cumulative UV damage that builds up over decades of life contributes meaningfully to the risk of developing surface and eyelid lesions.

Artificial Intelligence in Eye Lesion Detection

AI-assisted screening is gaining ground as a tool for detecting retinal and surface abnormalities. An AI system used in a large physical-examination population achieved a negative predictive value of at least 96% and a positive predictive value of at least 90% for identifying conditions such as drusen, maculopathy, optic cup enlargement, and retinal hemorrhage.²⁴ For surface lesions, AI algorithms trained on large image datasets show promise for identifying suspicious conjunctival lesions that may represent squamous neoplasia, with the goal of assisting ophthalmologists in early detection rather than replacing clinical judgment.²⁵

These tools are most useful in settings where access to a trained ophthalmologist is limited, such as community screening programs in rural areas or large-scale workplace health checks. They are not a substitute for a comprehensive dilated eye exam, but they are getting good enough to serve as a reliable first-pass filter that flags people who need a closer look. For anyone with a known lesion, established risk factors, or new visual symptoms, an in-person evaluation remains the standard of care.

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