Management of Recurrent Pterygium

Introduction

There is nothing quite as disheartening both for the patient and the surgeon than the recurrence of pterygium following surgery. This conundrum has likely occupied the minds of ophthalmologists for millennia and although much less common than in the past, still persists. As for primary pterygium, the ultimate aim in treating recurrent pterygium is to restore the ocular surface anatomy, function, and cosmesis, and alleviate all associated symptoms. This is invariably more difficult to achieve following recurrence, but nonetheless, a perfect surgical and cosmetic result should be the surgeon’s goal. We believe that reconstructive rather than destructive techniques are more likely to achieve these aims.

Aims and Definitions

With improvements in surgical outcomes and minimal recurrence rates, good ocular surface rehabilitation and cosmesis, earlier intervention has been advocated to minimize impact on corneal shape/refractive error/corneal aberrations. Aiming to keep induced astigmatism at less than 0.5 D results in a minimal effect on visual acuity and avoids corrective refractive procedures. Another positive is that later in life, the patient will experience the benefit of high-quality intraocular lenses, which is particularly important given the association between the presence of pterygium and cataract.

While the indications for primary pterygium surgery have been well enunciated ( Table 145.1 ), indications for surgery for a recurrence, while overlapping, are less clear. Furthermore, some believe that “recurrent pterygia are more troublesome than their antecedents.” While many have reported increased recurrence rates for the removal of already recurrent pterygia, ^, another study reported no statistical difference in recurrence rates between primary and recurrent groups.

Furthermore, the definition of “recurrence” varies among studies and should be the subject of a global Delphi panel, as has occurred, for example, in keratoconus diagnosis. In the future, a scoring system could, perhaps, be used to accurately define recurrence, distinguishing better between clinical and anatomic disease.

Recurrence has been defined as any fibrovascular growth extending across the limbus onto the cornea (at the site of surgical excision) ^{, ,} that:

• is not present at postoperative day 1

• excludes deeper corneal vessels and scarring

• attains the same degree of corneal encroachment as the original lesion, or

• has a regrowth exceeding 1 mm onto the cornea (also 1.5 mm, 2 mm) “with conjunctival drag”

Conjunctival recurrence has been defined as a gathering of tissue aimed at and extending up to the limbus–the “gathering” of conjunctiva.

Stages of recurrence have been described:

• 1.

  A few blood vessels growing in a triangular fashion from the plica—noticed on close inspection.

• 2.

  Definite conjunctival recurrence—blood vessels + subconjunctival connective tissue reaching almost to the limbus ± blood vessels reaching 1–2 mm on to the cornea.

• 3.

  Frank corneal recurrences—do not usually progress further than the limit of the original pterygium.

• 4.

  Aggressive recurrence—a thick, fleshy recurrence that can grow over the cornea in 1 month, dragging the caruncle and plica and is adherent to the sclera and may be associated with symblepharon formation. This is sometimes termed “malignant recurrence,” but this term is best avoided since it could be confused with the presence of premalignant/malignant changes found in pterygia in ∼2.5%–75% of cases. For this reason, all excised pterygia and, particularly, recurrent pterygia should be submitted for pathological examination, since intraocular invasion, orbital and sinus extension, ^, and the potential for metastatic death have been reported.

While this lack of consensus on the definition of recurrence persists, it will affect the reporting of the results of various studies. Furthermore, most of the descriptions of recurrence are still based on slit lamp descriptions and photography. Just as we have demonstrated “preclinical” evidence of invasion of the cornea by cell clusters (Fuchs flecks) —likely transformed limbal stem cells— similar events may occur before a recurrence is clinically obvious. New imaging modalities, such as in vivo confocal microscopy, may provide early documentation of impending recurrence so that early treatment may be instigated. Optical coherence tomography (OCT) imaging can also better define precisely when the head of a recurrent pterygium invades the cornea and can be used to measure pterygium thickness and depth of recurrence as a predictor of postoperative corneal opacity. It may also be of interest to examine topography, as it is not clear at what time corneal shape changes occur during the evolution of a recurrence. Investigation of tear film inflammatory parameters such as matrix metalloproteinase-9 may also provide some indication that a recurrence is developing, and tear film osmolarity could be measured as an indication of consequent development of dryness.

Pterygium recurrence is most likely to occur within 12 months of initial excision, with a 50% chance that there would be a recurrence within the first 120 days.

Risk Factors for Pterygium Recurrence

A wide variety of risk factors for recurrence have been reported and reviewed ( Table 145.2 ). ^,

Perhaps the most important of these factors are those that can be managed perioperatively.