Ocular Manifestations of Vitamin A Deficiency

Introduction

Nutritional deficits can have broad consequences on the overall health of a person. Vitamin A deficiency reflects primarily in the eyes and precipitates a diverse range of eye issues. When it lingers and remains for a significant period, it can also bring about life-threatening conditions. Prompt management with vitamin A supplements and medicated eyedrops can check the advancement of the condition and safeguard the eyesight.

What Is Vitamin A Deficiency?

• The human body needs every nutrient in the specified proportion to maintain the usual health and functioning of structures and organs. Any disruptions in the amount of nutrient intake reflect insufficiency or excess in the body. Both conditions can have serious health implications.

• When a person fails to incorporate a sufficient quantity of vitamin A in their daily food intake, it results in vitamin A deficiency (VAD).

• However, VAD also develops when there is trouble in vitamin absorption. In such conditions, even if the person consumes an adequate quantity of dietary vitamin A, it will not get absorbed into the body, eventually giving way to VAD.

• Conditions affecting the bodily absorption of A vitamin include Crohn's disease (affecting the large and small intestines), chronic diarrhea (loose stool over a period), giardiasis (parasitic disease), and pancreatic insufficiency (failure of the pancreas to produce enzymes in the required amount).

• Likewise, some people develop VAD due to underlying diseases like liver disease, which complicates vitamin A storage. Inadequacy of vitamin A is reported to have a spectrum of manifestations affecting the skin, bones, teeth, and eyes.

• However, vitamin A is a critical vitamin that aids in a person's vision, so any form of a deficit from its average level projects significant visual change and affects the healthy functioning of human eyes.

• Vitamin A is concerned with producing certain eye pigments, which form the eye's retinal layer (light-sensing layer), thereby directly facilitating vision.

What Are the Ocular Manifestations of Vitamin A Deficiency?

Inadequacy in the vitamin A level manifests a broad range of signs and symptoms involving the eye. These symptoms are altogether categorized under the term xerophthalmia. Some of the routinely encountered manifestations include the following:

1. Night Blindness

• It is the most extensively reported ocular manifestation of VAD. Nyctalopia is a widely used synonym for night blindness, where the person experiences trouble seeing objects in faded and compromised light conditions.

• It is frequently reported in the female population, typically affecting the younger population (children).

• As the name suggests, it impacts night vision. Night vision is aided by specialized cells in the retinal layer that is medically known as rod cells. It encompasses rhodopsin, which is a pigment protein. Rhodopsin makes vision possible in compromised light conditions. Vitamin A is responsible for stimulating rhodopsin.

• The affected person also has trouble accommodating sudden shifts in the light quality. The peculiar feature is that the person does not encounter any issues in daylight vision. It is regarded as an early sign of VAD.

2. Corneal Xerosis

• The insufficiency of vitamin A precipitates corneal xerosis all of a sudden. The cornea appears misty and dry.

• Tear-producing glands in the conjunctiva stop functioning, which exacerbates in the form of severe dryness. Furthermore, the dryness elevates the risk of getting eye infections.

• Corneal xerosis begins in the form of tiny disintegration of the cells in the cornea, which, when left unattended and untreated, advances into individual ulcers. Vitamin A supplements successfully tackle the condition when treated at the right time.

3. Bitot's Spots

• These are specific spots that appear in the white portion of the eye. Bitot's spots are hallmark findings that distinguish VAD ocular defect from other eye disorders.

• The spots appear bubbly and dry with a typical off-white color. These bubbly spots encompass exfoliated cells and certain bacteria belonging to the species Corynebacterium.

• It often appears as embossed (raised) dots in the conjunctiva (protective layer covering the sclera).

4. Conjunctival Xerosis

• Like corneal xerosis, when dryness develops over the conjunctival surface, it gives rise to conjunctival xerosis.

• In addition, the conjunctiva also elicits typical foldings creating a wrinkled appearance on clinical examination. Pigmentation and discolorations do develop in some regions of the conjunctiva.

• Initially, the discoloration develops as tiny pinpoint dots, which eventually extend into more areas of the conjunctiva and precipitate a distinct smoky look.

5. Corneal Ulceration

• Corneal ulceration is the advanced stage of corneal xerosis, where the patient develops tiny ulcers in the cornea.

• These ulcers sometimes get infected with microbial agents, producing severe eye redness and pain. The eyes then appear watery and flamed.

• The eyelids bulged, and there will be occasional discharge from the eyes.

6. Keratomalacia

• Keratomalacia is a complication of corneal xerosis and the result of corneal ulceration. The cornea (outer eye layer) develops tiny lesions through the disintegration of the cellular layer of the cornea.

• The cornea liquefies and softens, which threatens the vision of a person. The corneal cells undergo gross destruction and die out.

• Furthermore, it culminates in corneal scarring, where the liquified areas develop permanent scars over the areas, which significantly impact a person's vision and eventually end up in vision loss.

• It is an ophthalmic exigency that demands immediate medical assistance.

7. Xerophthalmic Fundus

• The inner eye portion develops alterations and disruptions in the structure and function. It develops as a result of long-standing vitamin A insufficiency.

• Functional disruptions are encountered first, followed by disruptions in the anatomy of the eye.

What Treatment Interventions Are Available for the Ocular Defects Arising From Vitamin A Deficiency?

As the conditions are precipitated by insufficiency of vitamin A, supplementation of the vitamin aid in tackling the deficiency, thereby dealing with the manifestations. Either intramuscular (into muscles) or oral administration of a high vitamin A dose is considered the hallmark treatment strategy for VAD. The condition should be treated appropriately in the presence of an underlying disease condition that reflects VAD. Eye lubricants and topical retinoic acid (eyedrops) also effectively deal with dryness and ocular ulcers.

Conclusion

Inadequacy in vitamin A projects a spectrum of eye issues that necessitates immediate attention and medical assistance. If ignored, it can destroy a person's vision over time. Timely management within the initial stages ensures prompt recovery of the person's sight. Vitamin A supplementation in the required form arrests the disease progression and tackles vision loss.