Conjunctival prolapse is a scleral lens complication in which the negative pressure created under the lens pulls the conjunctival tissue into the peripheral space between the lens and cornea. The limited literature available reported a prevalence of 20% to 37% in scleral lens wearers (Courey et al, 2018; Fisher et al, 2021).

Despite this being a relatively common complication, the long-term implications are still not well understood. Most patients who have mild prolapse are asymptomatic, although some may complain of a cosmetic difference in the affected area (Figure 1). However, if the prolapse is severe, it can result in adherence of the conjunctival tissue to the underlying cornea and can lead to vascularization or scarring (Figure 2). Thus, it is prudent to try to minimize conjunctival prolapse whenever possible.

How It Happens

One theory proposes that excessive vault of a scleral lens over the peripheral cornea allows the conjunctiva to migrate into the available space (Walker et al, 2016). So, minimizing that excessive space by flattening the transition zone that overlies the limbus could improve the condition. In cases in which there is excessive space due to a decentered lens, use customized haptic modifications to improve centration.

Fisher et al (2021) utilized anterior segment optical coherence tomography to observe the behavior of the conjunctiva in 10 young, healthy subjects wearing sclerals of varying post-lens fluid reservoir thickness (low, medium, and high). The peak of the prolapse was associated with greater limbal settling, suggesting that settling may lead to a greater suction force, resulting in this complication. Interestingly, it was not associated with landing zone tissue compression nor with horizontal asymmetry of the fluid reservoir thickness, which is not consistent with the aforementioned theory.

Conjunctival prolapse is often observed in the inferior quadrant, because lid anatomy, lens weight, and gravity encourage the lens to decenter downward, creating a thicker fluid reservoir prism inferiorly. Fisher et al (2021) looked only at normal eyes and did not analyze vertical meridian asymmetry, which would be useful to look at in future studies, as inferior prolapse is common.

Occasionally, prolapse can also be caused by improper patient application technique. If a patient applies the lens with unnecessary force or at an angle that is not parallel to the floor, this may cause undue suction force and tissue entrapment. Re-educating patients on proper technique can reduce or resolve self-induced prolapse.

Other Solutions

Unfortunately, prolapse may persist in an otherwise well-fit lens, and neither fit nor application technique changes resolve the issue. It may also present or worsen as patients age and conjunctivochalasis becomes more prominent. In asymptomatic patients, mild prolapse can be monitored. In severe prolapse, a referral can be made for a conjunctival resection procedure.

Scleral lens specialists will frequently encounter conjunctival prolapse in clinical practice. More research in older patients and in those who have irregular corneas may be helpful in understanding the implications of conjunctival prolapse in the patient population most likely to be wearing scleral lenses. CLS

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