Pterygium is a common disorder of the ocular surface in which abnormal fibrovascular conjunctival tissue encroaches onto the cornea (1). The pooled global prevalence of pterygia is thought to be around 10%, but because it is largely caused by UV radiation, this can vary widely across geographical regions; while estimated to occur at rates 10 times higher in populations who live around the equator (2), pterygia can occur in any population that experiences regular sun exposure, and is more common in older patients, men, and those with concomitant dry eye disease (3). Beyond UV light, pterygia may also be precipitated by ocular chemical exposure, injuries, or chronic irritation and limbal stem cell loss (2).

Regardless of the immediate contributors, changes in local ocular surface homeostasis result in proliferative limbal stem cell clusters, epithelial metaplasia, active fibrovascular tissue, inflammation, and disruptions in Bowman’s layer. Progression of pterygium is thought to occur due to the disrupted limbal barrier, upregulated inflammatory cytokines, and increased production of growth factors and matrix metalloproteinases (2).

Though definitive treatment is limited to surgical excision, this may not be necessary if patients are not experiencing visual disturbances and are unbothered by their pterygium’s cosmetic appearance. However, pterygia can potentially progress and cause chronic redness and irritation, irregular astigmatism, visual impairment, and cosmetic concerns, all of which can significantly affect patients’ quality of life (2). When these issues necessitate surgery, understanding the techniques involved and what patients they will work best for is vital for both minimizing the risk of recurrence and achieving the best visual and cosmetic outcomes.

Preventing recurrence

Recurrence is a major issue in pterygium excision, occurring in up to 18% of patients who have previously undergone surgery. While risk for recurrence is multifactorial and has some demographic components (being more likely in male patients and those aged under 40 years) (4), the choice of surgical technique also plays a major role. 

Early approaches involved a bare sclera method, which was a simple excision followed by the re-epithelialization of the scleral bed. While this technique has largely fallen out of favor due to extremely high recurrence rates (in some studies, as high as 89%) (5), a recent analysis of the Intelligent Research in Sight (IRIS) Registry found that the bare sclera method is still used in as many as 15% of cases, and that these patients had a significantly greater five-year incidence of repeat pterygium excision than those using more modern techniques (6).

A better approach, and the one that I currently use in the majority of my cases, has been to use a combination of both a conjunctival autograft (CAG) and an amniotic membrane graft (AMG). I usually source the CAG from the superior conjunctiva, as it’s the most protected and therefore highest quality tissue we can access, and then place the AMG over both the harvest site and the site of the epithelial defect on the cornea. When placing the AMG over the corneal epithelial defect, I place it basement-membrane side down, so it acts as a scaffold and avoids the risk of dermal fibers getting incorporated into the cornea. I use fibrin glue to attach the AMG over the CAG harvest site, and then I cover the eye with a bandage contact lens (BCL) to keep everything in place. I then inject subconjunctival cefazolin and dexamethasone peripheral to the BCL.

My preferred BCL is the AIR OPTIX Night and Day (Alcon, Inc; Fort Worth, TX). It has a slightly smaller diameter and a lower water content than other soft lenses and is approved for up to 30 days of continuous wear, which is very helpful for keeping everything in place on the limbus during the healing period. I also strongly prefer the use of cryopreserved AMGs, typically AmnioGraft (BioTissue Inc; Miami, FL), as they better retain the anti-inflammatory, anti-scarring, and anti-angiogenic properties that are naturally present in the amnion than dehydrated formulations tend to do (7).

In my experience, this combined CAG and AMG approach has much better outcomes than other approaches; in fact, one large single-center prospective study found that it leads to recurrence rates of only around 1%, and excellent cosmetic outcomes in close to 90% of patients (8).

However, there are a couple of situations in which I may be cautious about this approach or look for another strategy. For example, in patients with glaucoma or ocular hypertension, harvesting an autograft from the superior conjunctiva can cause scarring and pose problems for future filtration surgery. These patients may be better suited to using just an AMG rather than a combined approach. In addition, patients with a double pterygium may not have enough tissue for a CAG on both sites; in cases like this, I would usually do the CAG on the larger or more inflamed site and AMG alone on the other.

Pre- and postoperative considerations

Inflammation contributes to the likelihood of pterygium recurrence (1), and as such, needs to be proactively managed both pre- and postoperatively. Preoperatively, I typically use topical steroids to get any inflammation under control and, if blepharitis or blepharoconjunctivitis are present, initiate the patient on an antiparasitic agent for Demodex mites. Postoperatively, we prescribe prednisolone acetate 1% between four and six times a day, preservative free antibiotic eye drops four times a day, and a dexamethasone ointment at night. We typically keep patients on this regimen for two weeks, after which we re-evaluate; if they are healing well, we can begin to taper them off, but if not, we may keep them on for another two weeks. Counseling patients around behavior is also critical, and they need to be warned to use sun protection, avoid ocular exposure to water, and refrain from eye rubbing during this time period.

Conclusions

Ultimately, pterygium excision is a labor of love. Every surgery is unique and requires a meticulous, almost artistic approach that cannot be rushed. By respecting its complexity and taking the time to understand the factors at play in each individual eye, we can minimize recurrence risk and ensure our patients get the best possible visual and cosmetic outcomes.