Ocular Surface Disease in Patients With Glaucoma

Ocular surface disease in patients with glaucoma can take several manifestations including superficial punctate keratitis, tear-film instability, allergy, and even cicatrizing conjunctivitis. Superficial punctate keratitis is seen clinically by using various stains on the cornea and conjunctival surfaces and grading their severity and locations. Several authors have demonstrated effects of the medication and preservatives leading to the punctate keratitis. Several studies have found a significant difference in punctate keratitis when comparing treatment with glaucoma medication alone versus with a preservative. The rate of superficial punctate keratitis in patients with glaucoma receiving topical therapy can be as high as 18% to 54% The tear-film instability is functionally measured by TBUT, Schirmer test, osmolarity, and Meibomian gland scores. Studies have reported abnormal TBUT and Schirmer values in over 60% of glaucoma patients. Hyperosmolarity is also an important factor but is not completely understood.Allergic manifestations occur from glaucoma medications as well as their preservatives. They manifest in the form of conjunctival and periorbital hyperemia, chemosis, lid edema, and even eczema and itching. The symptoms are hypersensitivity reactions in the form of types 1 to 4. Fortunately, the vast majority of the symptoms resolve after withdrawal of the offending agent. Allergic conjunctivitis and dermatitis to prostaglandin analogs are relatively rare reported at 1.5%.Topical carbonic anhydrase inhibitors can cause dermatitis and conjunctivitis at a rate of 3% to 4%.Beta-blockers have been shown to cause contact dermatitis in 11% to 13% of patients. Topical alpha-agonist, brimonidine, can cause a conjunctivitis with follicles in up to 11.5%. Pseudopemphigoid is a cicatrizing conjunctivitis that mimics ocular mucous membrane pemphigoid in its presentation and requires a conjunctival biopsy to distinguish them. The largest publication to evaluate this disease was by Thorne et al who showed that 28.3% of all cases of pseudopemphigoid were due to topical glaucoma medications (beta-blockers 87.8%, epinephrine and alpha-agonists 61%, miotics 53.6%). Most of these cases were receiving multiple agents; hence, it was not possible to conclude which medications contributed to the presumed drug-induced pseudopemphigoid.Ocular surface disease is accompanied by increased osmolarity of the tear film and inflammation of the ocular surfaceCommon dry eye symptoms include itching, burning, stinging, pain, soreness, sticky eyes, photosensitivity, foreign body sensation, blurred vision, poor vision, redness, intolerance to windy conditions, and contact lenses.Both ocular surface disease and glaucoma can affect the quality of life. There are several validated quality of life questionnaires that correlate closely with clinical indices of severity. Poorer quality of life scores are associated with worse functional status and increased visual morbidity. There was also an association between increasing number of drops and decreasing emotional well-being scores based on Impact of Dry Eye on Everyday Life questionnaire (Alcon, Fort Worth, TX). Skalicky et al found that ocular surface disease is more common with increasing glaucoma severity and is associated with poorer visual function and glaucoma-related quality of life and also higher exposure to benzalkonium chloride (BAK).