Conjunctival Cyst: Causes, Symptoms, and Removal Options

A conjunctival cyst is a fluid-filled sac that forms on the conjunctiva, the thin membrane covering the white part of the eye and inner eyelids. While often benign, these cysts can cause discomfort or affect vision depending on their size and location.

Physical Features

A conjunctival cyst appears as a translucent or semi-transparent sac on the conjunctiva, varying in size from a few millimeters to larger formations that may extend across the ocular surface. Its thin walls allow the fluid inside to be visible, giving it a characteristic clear or slightly yellowish hue. Depending on location, the cyst may be more noticeable when the eye moves or when the eyelid is pulled back. Some remain small and inconspicuous, while others enlarge over time, potentially interfering with blinking or eye movement.

The texture is generally smooth and fluctuant, meaning it compresses slightly under pressure before returning to its original shape. Unlike solid growths, these cysts contain serous or mucoid fluid, which can shift within the sac when the eye moves. Repeated friction from blinking or rubbing may cause the outer membrane to thicken slightly, making it more resistant to rupture. Some cysts may develop fibrotic changes over time, leading to a firmer consistency.

The cyst’s location influences its effect on the eye. Those on the palpebral conjunctiva, lining the inner eyelid, may cause a foreign body sensation, especially when blinking. Cysts on the bulbar conjunctiva, covering the sclera, are more visible and may create a raised area on the eye’s surface. In rarer cases, cysts develop within the conjunctival fornix, making them less noticeable but potentially more irritating. The cyst’s position also affects how light interacts with it—some appear more prominent under direct illumination, while others blend into the surrounding tissue unless examined closely.

Causes

Conjunctival cysts can develop due to trauma, surgical history, or structural anomalies within the conjunctival tissue. One of the most common causes is mechanical irritation or minor injury, leading to epithelial cells becoming trapped beneath the surface. These cells may continue to produce fluid, forming a cyst. This can occur from accidental eye rubbing, foreign body exposure, or minor abrasions from contact lenses. Individuals who frequently wear contact lenses, particularly poorly fitted or extended-wear varieties, face a higher risk due to repeated friction and microtrauma.

Surgical interventions, such as pterygium excision, strabismus surgery, or glaucoma filtration surgery, can also lead to cyst formation. In these cases, cysts may develop due to improper healing, where conjunctival epithelial cells become trapped within the surgical site. A retrospective review published in Cornea found that post-surgical inclusion cysts accounted for a significant portion of cases, particularly in patients with multiple ocular procedures. The risk increases when surgical wounds do not heal uniformly, creating pockets where fluid can accumulate. Certain suturing techniques or tissue grafts may also contribute by altering normal conjunctival architecture.

Some individuals are born with conjunctival cysts due to developmental anomalies. These congenital cysts arise when remnants of embryonic conjunctival tissue become encapsulated. Unlike acquired cysts, congenital variants often remain asymptomatic unless they enlarge or interfere with eye movement. Histopathological evaluations suggest these cysts originate from embryologic sequestration rather than external trauma or irritation.

Infections and inflammatory conditions of the conjunctiva, particularly chronic conjunctivitis, can also contribute to cyst formation. Recurrent inflammation can cause structural changes in the conjunctiva, promoting cystic spaces. Certain bacterial or viral infections, such as adenoviral conjunctivitis, have been associated with secondary cyst formation due to prolonged irritation and fluid accumulation. A study published in the British Journal of Ophthalmology found a higher incidence of cystic changes among patients with chronic conjunctival inflammation.

Symptoms Or Clinical Presentation

A conjunctival cyst often goes unnoticed in its early stages, especially if small and non-disruptive. Many individuals first become aware of it when they experience a subtle sensation of fullness or mild irritation, particularly when blinking. As the cyst enlarges, it can create a persistent foreign body sensation. This discomfort is more pronounced when located on the palpebral conjunctiva, where it comes into frequent contact with the eyelid. Contact lens wearers may find them increasingly uncomfortable as the lens presses against the cyst.

Larger cysts may cause visual disturbances, particularly if they disrupt the smooth curvature of the ocular surface. Light may refract abnormally over the raised area, leading to localized blurriness or distortion. If the cyst impinges on the cornea, it can induce irregular astigmatism, subtly altering visual acuity. Some individuals also report intermittent tearing, as the cyst can interfere with tear film distribution.

Repeated mechanical stress, such as rubbing, can make the cyst more pronounced in both appearance and sensation. Friction can cause localized redness due to increased vascularization. While not inherently painful, the cyst may become tender if secondary irritation occurs. In rarer cases, transient conjunctival edema can develop if the cyst obstructs normal tear outflow, causing mild swelling.

Diagnostic Techniques

A conjunctival cyst is evaluated using slit-lamp biomicroscopy, which provides a magnified view of the ocular surface. This allows ophthalmologists to assess the cyst’s transparency, vascular involvement, and structure. The slit-lamp also helps differentiate cysts from other conjunctival lesions, such as pingueculae or neoplastic growths, which may require different management.

For more detailed structural analysis, anterior segment optical coherence tomography (AS-OCT) provides high-resolution cross-sectional scans of the conjunctival layers, offering precise measurements of the cyst’s depth and internal reflectivity. AS-OCT is especially useful in distinguishing simple conjunctival cysts from deeper epithelial inclusions or subconjunctival fluid collections. In cases where the cyst appears atypical, ultrasound biomicroscopy (UBM) may be used to assess deeper ocular structures and rule out underlying pathology.

Treatment And Removal

Management depends on the cyst’s size, symptoms, and impact on vision or comfort. Small, asymptomatic cysts often resolve on their own, requiring no intervention. Ophthalmologists typically recommend avoiding excessive eye rubbing or irritation. Lubricating eye drops can reduce friction, alleviating discomfort. If inflammation occurs, short-term topical anti-inflammatory medications may be prescribed.

For persistent, enlarging, or bothersome cysts, removal options include needle aspiration or surgical excision. Needle aspiration uses a fine-gauge needle to drain the fluid, providing immediate relief, though recurrence is common since the cyst lining remains intact. To reduce regrowth, some ophthalmologists inject a sclerosant, which induces fibrosis and prevents fluid reaccumulation.

For recurrent or larger cysts, surgical excision is preferred. Performed under local anesthesia, this procedure involves carefully dissecting the cyst from surrounding tissue to ensure complete removal while preserving the conjunctiva. Precision is crucial to prevent regrowth, as residual epithelial cells can lead to recurrence. Postoperative care includes antibiotic eye drops to prevent infection and monitoring for signs of recurrence or scarring.

Potential Complications

Although generally benign, untreated or improperly managed conjunctival cysts can lead to complications. Persistent irritation is common, particularly when the cyst is subjected to frequent mechanical stress from blinking or eye movements. Prolonged friction can cause surface inflammation, leading to conjunctival hyperemia and localized swelling. Chronic irritation may result in epithelial thickening, making the cyst more resistant to spontaneous resolution and potentially necessitating surgical intervention. Contact lens wearers may experience difficulty achieving a comfortable fit due to altered ocular surface contours.

Following surgical excision, recurrence remains a concern, especially if epithelial cells are left behind. Studies indicate that incomplete removal can lead to regrowth within months, sometimes requiring repeat procedures. Excessive scarring may cause conjunctival contracture, restricting eye movement or leading to dry eye symptoms if tear distribution is affected. In rare cases, secondary infections can develop postoperatively, particularly if proper hygiene and care are not observed. While complications are uncommon with meticulous surgical technique, patients should be aware of infection signs such as persistent redness, discharge, or increasing pain, ensuring timely intervention if needed.