What Is Xerophthalmia?

Xeropthalmia is the abnormal dryness of the conjunctiva and cornea of the eye and is caused by a lack of vitamin A. If treatment is not sought for this illness, it may result in irreversible vision loss or in some cases, blindness. Over five million children under the age of 6 around the world are affected with xerophthalmia, a condition that continues to be a public health concern.¹ This condition is especially prevalent in poor communities that suffer from food insecurity and malnutrition. A better understanding of the causes, symptoms, diagnosis, and treatment options for xerophthalmia can help reduce the risk of vision loss caused by the condition.

Causes and risk factors

The most common cause of xerophthalmia is a deficiency in either the consumption or absorption of vitamin A. Vitamin A, which is also known as retinol, is a vital nutrient that plays an important role in maintaining the epithelium of mucous membranes and the cornea.  A deficiency in vitamin A causes the lacrimal and meibomian glands in the eye to become dysfunctional, which in turn reduces tear secretion. This results in the drying out of the conjunctiva (also known as conjunctival xerosis) and the opacification of the cornea (also known as corneal xerosis). 

Children under the age of 6, pregnant women, and those with cystic fibrosis, celiac disease, liver diseases, or malnutrition are among the populations that have the highest risk of contracting xerophthalmia.² These susceptible populations have a reduced ability to absorb vitamin A and other nutrients from food. 

The natural decline in tear production that comes with getting older also makes elderly people more susceptible to this condition. Xeropthalmia can also be a side effect of some medications, including isotretinoin, antidepressants, diuretics, and anti-inflammatory drugs, which can reduce tear secretion. 

Additional environmental risk factors include places that are dry, dusty or windy and that have high levels of sun exposure.  

Signs and symptoms

Night blindness, also known as nyctalopia, is a mild symptom of a vitamin A deficit. Night blindness is caused by defective dark adaptation resulting from impaired rod function in the eyes.² As the severity of the vitamin A insufficiency increases, xerosis of the conjunctiva will develop. This will result in a dry, gritty, and painful sensation in the eyes, in addition to photophobia and excessive tear production.² Following xerosis of the eyes, some visible symptoms may occur:

• Bitot’s spots: These are keratin deposits that are frothy and superficial and appear on the conjunctiva
• Xerosis of the conjunctiva: Characterised by dryness, thickness, wrinkles, and scarring on the eye

If these initial symptoms are not treated, then the condition will progress and begin to damage the cornea. The symptoms progress to include ocular pain, discharge, tear production, and hazy vision. Corneal manifestations include the following:  

• Corneal xerosis: Manifests clinically as dryness, cloudiness, softness, and haziness
• Corneal ulcers: Characterised by pitting flaws, lesions, and scarring
• Corneal necrosis: Severe scarring, keratomalacia, perforation, and loss of eyesight

Infections such as bacterial keratitis become more common as the outer layers of the eye lose their integrity. If the condition is not properly handled, potential complications include scarring of the cornea, vascularisation, the development of staphylomas, and total blindness. 

Diagnosis and testing

It is essential to make a prompt diagnosis of xerophthalmia by both a physical examination and laboratory tests to forestall or prevent blindness. Screening programmes for public health aid in the early detection and intervention of disease.

Medical history 

Typically, the first step in a xerophthalmia diagnosis is to take a full medical history of the patient. Healthcare professionals will likely focus on the patient's diet, the usage of any drugs or medications that diminish tear production, the symptoms that are being experienced, and any concomitant illnesses such as cystic fibrosis or liver disease that influence vitamin A absorption or storage.³

Eye examination

An ophthalmologist will examine the external eye for symptoms of dryness, Bitot’s spots, cloudiness of the cornea, and scarring of the conjunctiva and cornea. Fluorescein dye can be used to stain the eye, which can help make flaws more visible.⁴ Slit-lamp biomicroscopy provides a more in-depth assessment of any abnormalities that may be present.⁵ The thickness of the tear film is also measured.

Schirmer’s test 

Thin strips of filter paper are inserted under the eyelid to assess tear production.  Ocular dryness is indicated when wetting is less than 10mm after 5 minutes has passed. Patients who have xerophthalmia typically have very low values.

Blood tests

Vitamin A levels in the blood are measured and analysed. Deficiency is confirmed when serum retinol concentrations are less than 0.7 mol/L (20 mg/dL).

Dark adaptometry 

The thresholds of light sensitivity are measured using a dark adaptometry test to evaluate the eye’s ability to adapt to the dark.  It can provide a quantitative measure of the severity of night blindness.⁵

Ocular imaging

Evaluation of corneal damage could involve the use of optical coherence tomography, corneal topography, or any number of other imaging techniques. The use of cultures allows for the detection of illnesses.

Treatment and management

Treatments typically target vitamin A deficiency in order to restore the health of the ocular surface. Additional treatments are intended to ease symptoms and reduce corneal damage.⁶

Vitamin A supplementation

To restore vitamin A levels, a high dose can be taken by mouth or injected into the muscle. Doses ranging from 100,000 to 400,000 IU are administered over several days, depending on the patient's age and the severity of the deficiency.³

Topical lubrication 

Lubricants such as artificial tears, gels, and ointments can be used to provide the eye with moisture and comfort.  Antibiotics or antivirals are often prescribed in cases of infection.^1,3

Surgical procedures 

Healing of corneal ulcers can be aided by grafts made of amniotic membrane. Scarring that is severe enough to affect the cornea may necessitate transplantation. Tarsorrhaphy involves partially stitching the eyelids shut to shield the cornea.

Supportive care

To manage symptoms, it is advised to stop using medications that cause dry eye, to wear sunglasses outside, to use humidifiers, and to stay away from dry and windy environments.⁷ 

Dietary improvement 

Increasing one's consumption of vitamin A-rich foods such as dairy, liver, fish, and orange and green vegetables can assist in the maintenance of normal levels. Some populations receive supplements in their foods, such as rice, to try and increase vitamin A intake.⁸

Follow-up

Patients need to be closely monitored to ensure that their vitamin A levels return to normal and they can maintain their corneal protection. Education in public health can prevent future occurrences.

Xerophthalmia is a disease that has the potential to cause blindness, but this can be prevented with early diagnosis and appropriate treatment. Ongoing studies are aimed at furthering efforts to improve management strategies and results.

Public health considerations

Global prevalence

The World Health Organisation (WHO) estimates that around 5.2 million children in the preschool age range (6 months to 6 years) have xerophthalmia, with the majority of cases occurring in Africa and Southeast Asia. One of the most avoidable causes of childhood blindness is a lack of vitamin A.

High-risk populations

Those who are most at risk include children aged 6 months to 6 years, pregnant women, and patients with cystic fibrosis, celiac disease, liver illness, or malnutrition.⁹ Increasing their vitamin A consumption and/or absorption should be their top priority.  

Prevention strategies

The practice of breastfeeding offers vitamin A to infants and can reduce the likelihood of developing xerophthalmia.¹⁰  Through the process of food fortification, vitamin A is added to foods that are commonly consumed. Also, taking vitamin A in the form of tablets or injections can help prevent deficiency. It is also recommended to vary one's diet to incorporate sources of vitamin A that are abundant in plants and animals.

Policy initiatives

Global efforts aim to address underlying issues such as poverty, food insecurity, and poor access to healthcare to sustainably enhance the vitamin A intake and status of groups that are at risk.

Monitoring and surveillance 

Screening at-risk populations regularly makes it possible to diagnose and treat cases of eye disease early, preventing blindness. Through ongoing observation, high-load locations have been identified, allowing increased intervention in these areas.¹¹

The eradication of xerophthalmia demands a multidimensional strategy for public health that combines clinical care, public education, nutrition interventions, and modifications to social policies.

Summary

In children, xerophthalmia is a leading cause of blindness, making it a pressing public health challenge. If the vitamin A status is not improved, the symptoms of dry eye might result in permanent damage to the cornea. When combined with case detection, education, and clinical management, efforts made by public health organisations to address vitamin A deficiency through population-level nutrition programmes can effectively lower the occurrence of xerophthalmia. Addressing this preventable illness via a variety of strategies has the potential to save the sight of millions of people who are at risk for vitamin A deficiency and improve their overall health.