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Lacrimal System Dysfunction
Noninfectious keratopathy characterized by reduced moistening of the con-junctiva and cornea (dry eyes).
Epidemiology: Keratoconjunctivitis sicca as a result of dry eyes is one of
themost common eye problems between the ages of 40 and 50. As a result of
hor-monal changes in menopause, women
are far more frequently affected
(86%) than men. There are also
indications that keratoconjunctivitis sicca is more prevalent in regions with
higher levels of environmental pollution.
Etiology: Keratoconjunctivitis sicca results from dry eyes, which may be dueto one of two causes:
❖ Reduced tear production associated with certain systemic disorders (suchas Sjögren’s syndrome and rheumatoid arthritis) or as a result of atrophy or destruction of the lacrimal gland.
❖ Altered composition of the tear film. The composition of the tear film canalter due to vitamin A deficiency, medications (such as oral contraceptives and retinoids), or certain environmental influences (such as nicotine, smog, or air conditioning). The tear film breaks up too quickly and causes corneal drying.
Dry eyes can represent a disorder in and of itself.
Symptoms: Patients complain of burning, reddened eyes, and excessive lacri-mation (reflex lacrimation) from only slight environmental causes such as wind, cold, low humidity, or reading for an extended period of time. A foreign body sensation is also present. These symptoms may be accompanied by intense pain. Eyesight is usually minimally compromised if at all.
Diagnostic considerations: Often there is a discrepancy between themini-mal clinical findings that the ophthalmologist can establish and the intense symptoms reported by the patient. Results from Schirmer tear testingusuallyshow reductions of the watery component of tears, and the tear break-uptime (which provides information about the mucin content of the tear filmwhich is important for its stability) is reduced. Values of at least 10 seconds are normal; the tear break-up time in keratoconjunctivitis sicca is less than 5 seconds.
Slit lamp examination will reveal dilated conjunctival vessels and minimalpericorneal injection. A tear film meniscus cannot be demonstrated on the lower eyelid margin, and the lower eyelid will push the conjunctiva along in folds in front of it.
In severe cases the eye will be reddened, and the tear film will contain thick mucus and small filaments that proceed from a superficial epithelial lesion (filamentary keratitis; see Fig. 5.11). The corneal lesion can be demonstrated with fluorescein dye. In less severe cases the eye will only be reddened, although application of fluorescein dye will reveal corneal lesions (superficial punctate keratitis;). The rose bengal test and impressioncytology are additional diagnostic tests that are useful in evaluat-ing persistent cases.
Treatment: Depending on the severity of findings,artificial tear solutionsinvarying viscosities are prescribed. These range from eyedrops to high-viscos-ity long-acting gels that may be applied every hour or every half hour, depending on the severity of the disorder. In persistent cases, the puncta can be temporarily closed with silicone punctal plugs (Fig. 3.11) to at least retain the few tears that are still produced. Surgical obliteration of the puncta may be indicated in severe cases.
Patients should also be informed about the possibility of installing an airhumidifier in the home and redirecting blowers in automobiles to avoidfurther drying of the eyes. Dry eyes in women may also be due to hormonal changes, and a gynecologist should be consulted regarding the patient’s hor-monal status.
Prognosis: The prognosis is good for those treatments discussed here.
However, the disorder cannot be completely healed.
Illacrimation or epiphora may be due to hypersecretion from the lacrimalgland. However, it is more often caused by obstructed drainage through the lower lacrimal system.
❖ Emotional distress (crying).
❖ Increased irritation of the eyes (by smoke, dust, foreign bodies, injury, orintraocular inflammation) leads to excessive lacrimation in the context of the defensive triad of blepharospasm, photosensitivity, and epiphora.
❖ Stricture or stenosis in the lower lacrimal system.
❖ Eyelid deformity (eversion of the punctum lacrimale, ectropion, or entropion).
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