Infectious and Inflammatory Conditions
Inflammation and infection of eye structures are common. Eye infection is a leading cause of blindness worldwide. Table 58-7 describes selected common infections and their treatment.
DRY EYE SYNDROME
Dry eye syndrome, or keratoconjunctivitis sicca, is a deficiency in the production of any of the aqueous, mucin, or lipid tear film components; lid surface abnormalities; or epithelial abnormali-ties related to systemic diseases (eg, thyroid disorders, Parkinson’s disease), infection, injury, or complications of medications (eg, antihistamines, oral contraceptives, phenothiazines).
The most common complaint in dry eye syndrome is a scratchy or foreign body sensation. Other symptoms include itching, ex-cessive mucus secretion, inability to produce tears, a burning sen-sation, redness, pain, and difficulty moving the lids.
Slit-lamp examination shows an absent or interrupted tear menis-cus at the lower lid margin, and the conjunctiva is thickened, ede-matous, hyperemic, and has lost its luster. A tear meniscus is the crescent-shaped edge of the tear film in the lower lid margin. Chronic dry eyes may result in chronic conjunctival and corneal irritation that can lead to corneal erosion, scarring, ulceration, thinning, or perforation that can seriously threaten vision. Sec-ondary bacterial infection can occur.
Management of dry eye syndrome requires the complete cooper-ation of the patient with a regimen that needs to be followed at home for a long period, or complete relief of symptoms is un-likely. Instillation of artificial tears during the day and an oint-ment at night is the usual regimen to hydrate and lubricate the eye through stimulating tears and preserving a moist ocular sur-face. Anti-inflammatory medications are also used, and moisture chambers (eg, moisture chamber spectacles, swim goggles) may provide additional relief.
Patients may become hypersensitive to chemical preservatives such as benzalkonium chloride and thimerosal. For these pa-tients, preservative-free ophthalmic solutions are used. Manage-ment of the dry eye syndrome also includes the concurrent treatment of infections, such as chronic blepharitis and acne rosacea, and treating the underlying systemic disease, such as Sjögren’s syndrome (an autoimmune disease).
In advanced cases of dry eye syndrome, surgical treatment that includes punctal occlusion, grafting procedures, and lateral tar-sorrhaphy (ie, uniting the edges of the lids) are options. Punctal plugs are made of silicone material for the temporary or perma-nent occlusion of the puncta. This helps preserve the natural tears and prolongs the effects of artificial tears. Short-term occlusion is performed by inserting punctal or silicone rods in all four puncta. If tearing is induced, the upper plugs are removed, and the re-maining lower plugs are removed in another week. Permanent occlusion is performed only in severe cases among adults who do not develop tearing after partial occlusion and who have results on a repeated Schirmer’s test of 2 mm or less (filter paper is used to measure tear production).