Xerosis is a complex condition characterized by abnormal dryness of the conjunctiva and or the cornea (of the eye), the skin, or mucous membranes. More specifically, when dryness affects the conjunctiva of the eye, it is known as conjunctival xerosis.
Causes of Xerosis
It is actually a group of signs that show the damage of corneal and conjunctival epithelium due to reduction in the quality and/or quantity of lacrimal fluid. Lacrimal fluid is required for the formation of tear film that serves most important functions of vision and protection of eye. Any abnormality of tear film or lacrimal fluid can cause serious damage to the eye.
- Hypo secretive causes that cause reduction in the production of tears
- Deficiency of tears or conjunctival secretions
- Sjogren’s syndrome
- Hormonal imbalance
- Certain drugs like anti-histamines
- Vitamin A deficiency
- Infiltrative process (e.g. lymphoma)
- Neurological lesions (e.g. Riley-Day syndrome)
- Absence / abnormality of lacrimal gland / ductules
- Eye trauma
- Evaporative causes
- Deficiency of oily component of tear film
- Defective corneal resurfacing (e.g. lid malposition)
- Decreased Blinking disorders
- Excessive wearing of contact lens
Symptoms of Xerosis
The symptoms of xerosis get aggravated by air conditioning, prolonged reading or computer work, dry air etc.
- Feeling of a foreign body in the eye
- Excessive watering from eye
- Feeling of dryness in eye
- Burning and “sandpaper” in the eyes, especially due to wind, smoke, conditioned air, fan heaters etc.
- Photophobia or sensitivity to light
- Decreased vision towards evening
- Fluctuations in visual acuity within one working day
- Stringy mucus discharge
- Blurring of vision
- Presence of small triangular white patches on the outer rim of cornea (Bitot’s spot)
Diagnosis of Xerosis
Diagnosis of xerosis is typical and requires thorough examination of the eye including a visual acuity test to check the sharpness of vision and a visual field test to check the sight on the peripheral (side) areas of vision. The examination of pupil of the eye is done by dilating it with eye drops and then checking eyes with an instrument called an ophthalmoscope to evaluate the health of the retina and optic nerve. In addition to these, special dyes might be used in the eyes to reveal dry spots and corneal damage. Other tests required to confirm the diagnosis of xerosis include:
- Schirmer’s test
- Tear break-up test
- Tear Lysoszyme ratio
- Rose Bengal staining
Treatment & Drugs for Xerosis
Treatment of xerosis typically depends upon the disease severity and its cause.
- In cases where the cause of xerosis gets evaluated, treatment of the cause makes the first line of therapy.
- Light degree of the disease can also be managed with artificial tear drops, ointments and/or gels.
- Anti-inflammatory therapy is also recommended to provide symptomatic relief to the patient.
- Topical corticosteroids
- Therapeutic contact lens is used to protect eye membrane.
- Punctual occlusion by lacrimal silicone plugs or cauterization to delay the tear drainage.
Lateral tarsorrhaphy for the eyelid can also be done to reduce evaporation of tears
- Transplantation of the parotid duct into the conjunctiva sac may be tried in severe cases.
- Bitot spots may be scraped with a sharp spoon and painted with carbonic acid.
Complications of Xerosis
Xerosis is definitely not a minor condition that can be ignored. It needs to be treated properly to avoid any damage to the vision and other parts of the eye. If not treated, xerosis can lead to:
- Eye infections e.g. conjunctivitis
- Corneal complications like infection, ulceration and rarely, perforation
- Decreased visual acuity