PINGUECULA and PINGUECULITIS

Signs and Symptoms

Pingueculae are characterized by yellowish, slightly raised, interpalpebral exacerbations of tissue in the nasal and temporal bulbar conjunctiva.1-14 In most cases, pingueculae are an ancillary finding, causing little, if any, ocular symptoms. Research has linked the severity of pingueculae with exposure to ultraviolet light (chronic sunlight exposure, welding), contact lens wear (more so with rigid lenses) as well as natural conjunctivochalasis of the individual.11-14

Pterygia are wedge-shaped fibrovascular growths that evolve by progressing over top of pingueculae to extend onto the cornea. They are frequently, but not always, the byproduct of the chronic pathophysiological sequelae introduced by pingueculae.5 Both lesions possess vasculature and the potential to become inflamed. Both can disrupt tear flow, producing incomplete corneal wetting and resulting in corneal punctate epitheliopathy and adjacent areas of focal corneal dehydration with dellen formation.1-6 Despite these relationships and a high degree of coexistence and comorbidities, the literature continues to consider the two lesions as separate entities.14 When a pinguecula becomes acutely inflamed, producing focal conjunctival redness with accompanying ocular irritation, the condition is referred to as pingueculitis.4-8

Pathophysiology

Pingueculae are considered to be a conjunctival degenerative process initiated by exposure to noxious environmental stimuli and ultraviolet radiation.3-6,11,14 The initial lesion is thought to result from chronic exposure to solar radiation, which induces an alteration of the collagen and elastic tissues of the conjunctival stroma, leading to elastotic degeneration and deposition of abnormal elastic fibers in the conjunctival substantia propria.2,3,6

Histologically, the lesions contain deposits of degenerating collagen fibers, granular deposits, elastoid fibers and an increased population of metabolically active stromal fibrocytes.11 Once a pinguecula develops, depending on its size the tear film may become thin and discontinuous in that zone, producing a bed of dryness.1,2,11-14 When the tissue itself and neighboring cornea are sufficiently affected, inflammation ensues; vascular dilation allows histamine, seratonin, bradykinin and prostaglandins to be released, producing the acute irritative symptoms that characterize pingueculitis.11,14

In severe cases, the conjunctival surface becomes sufficiently dry to cause microulceration of the surface epithelium, damage to limbal stem cells with the release of matrix metalloproteinases and vascular endothelial growth factor-C (VEGF-C).14,15 These changes promote an increase in lymphatic microvessel density, which is the impetus for pterygium formation.1-3,8,14,15 Research has also suggested that, on the continuum of the same process, inflammatory cell infiltration may contribute to the formation of conjunctival inclusion cysts seen within pterygia, pingueculae, vernal conjunctivitis and pyogenic granuloma.8

Management

Management of pingueculae is predicated mostly on the nature and extent of symptoms. Patients who have occupations or hobbies that increase the risk of pinguecula formation should be counseled on the preventative benefits of protective sun wear such as UV-blocking coatings and goggles that limit dust exposure.4 In cases of mild pingueculitis, where symptoms are subtle, ocular lubricating drops are indicated. Nonsteroidal anti-inflammatory medications may also suppress discomfort until ocular surface homeostasis can be restored.14 When symptoms and inflammation become more significant, topical steroids such as 1% prednisolone acetate suspension, 0.5% loteprednol etabonate or 0.25% fluorometholone, Q2H–QID are acceptable.1,3,4,6,14

A recent report studying symptomatic pinguecula found that intralesional betamethasone injection in depot form provided a significant clinical improvement.16 Argon laser photocoagulation has also been documented as an effective and safe method for removing a pinguecula for cosmetic purposes.17 The method permits good control of the extent and depth of removal, minimizing conjunctival defects and other complications.17 The method is reserved for severe cases where the tissue interferes with vision, contact lens wear or corneal wetting. In this study, it was preferred over standard surgical resection.1-4,17

Clinical Pearls

Differential diagnoses must be considered when intrapalpebral conjunctival masses and elevations are discovered. Such lesions are not always benign and may include conjunctival dermoids, intraepithelial neoplasia (squamous cell carcinoma), phlyctenulosis, pannus, conjunctival retention cysts and limbal follicles.

While pingueculitis is typically self-limiting and rarely constitutes a sight threatening event, prompt treatment with topical lubrication and anti-inflammatory therapy hastens recovery and greatly helps to diminish symptoms.

Appropriate forms of UV-blocking eye wear can minimize the risk of pinguecula formation for those persons at elevated risk (e.g., people who fish, boaters, skiers, outdoor painters, roofers, etc.).

1. Azhar SS. Acute red eye. Pingueculitis. Am Fam Physician. 2007;76(6):857-8.

2. Archila EA, Arenas MC. The etiopathology of pinguecula and pterygium. Cornea. 1995;14 (5):543-4.

3. Wallace W. Diseases of the conjunctiva. In: Bartlett JD, Jaanus SD, eds. Clinical Ocular Pharmacology. Boston: Butterworth-Heinmann; 1984:583-648.

4. Cullom RD, Chang B. Cornea: Pterygium/Pingueculum. In: Cullom RD, Chang B, eds. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. Philadelphia: JB Lippincott; 1994:65-7.

5. Bergmanson JP, Soderberg PG. The significance of ultraviolet radiation for eye diseases. A review on the efficacy of UV-blocking contact lenses. Ophthalmic Physiologic Optics. 1995;15(2):83-91.

6. Cohen EJ, Rapuano CJ, Laibson PR. External Diseases. In: Tasman W, Jaeger EA, eds. The Wills Eye Atlas of Clinical Ophthalmology. Philadelphia: JB Lippincott; 1996:1-85.

7. Frucht-Pery J, Solomon A, Siganos CS, et al. Treatment of inflamed pterygium and pinguecula with topical indomethacin 0.1% solution. Cornea. 1997;16(1):42-7.

8. Suzuki K, Okisaka S, Nakagami T. The contribution of inflammatory cell infiltration to conjunctival inclusion cyst formation. Jpn J Ophthalmol. 2000;44(5):575.

9. Gul A, Goker H, Sabanci S, et al. Relationship between pinguecula formation and exposure to tandoor ovens in a hospital-based study. Int J Ophthalmol. 2014;7(6):1014-6.

10. Mimura T, Obata H, Usui T, et al. Pinguecula and diabetes mellitus. Cornea. 2012;31(3):264-8.

11. Yam JC, Kwok AK. Ultraviolet light and ocular diseases. Int Ophthalmol. 2014;34(2):383-400.

12. Mimura T, Mori M, Obata H, et al. Conjunctivochalasis: associations with pinguecula in a hospital-based study. Acta Ophthalmol. 2012;90(8):773-82.

13. Mimura T, Usui T, Mori M, et al. Pinguecula and contact lenses. Eye (Lond). 2010;24(11):1685-91.

14. Farjo QA, Sugar A. Conjunctival and corneal degenerations. In: Yanoff M, Duker JS. Ophthalmology. St. Louis, MO: Mosby-Elsevier; 2009:446-453.

15. Ling S, Liang L, Lin H. Increasing lymphatic microvessel density in primary pterygia. Arch Ophthalmol. 2012;130(6):735-42.

16. Arenas-Archila E, Arellano K, Muñoz-Sarmiento D. Intra-lesional injection of betamethasone for the treatment of symptomatic pinguecula. Arch Soc Esp Oftalmol. 2014;89(10):408-10.

17. Ahn SJ, Shin KH, Kim MK, et al. One-year outcome of argon laser photocoagulation of pinguecula. Cornea. 2013;32(7):971-5.