Pre-Ocular Tear

Comparative study between punctual plugs insertion and botulinum toxin type A injections in improvement of resistant dry eye diseases

Hazem Abdelrahman Ismail,MD.

Abstract

Purpose: To compare the efficacies of Botulinum toxin type A injection and punctal plugs insertion in dry eye diseases not responding to topical ordinary medications.

Materials and Methods: A randomized clinical trial of two parallel groups of 54 dry eye patients seen in our clinic not responding to ordinary topical medications were divided into two groups. One group received Botulinum toxin type A injections and the other group received punctal plugs insertion to prevent lacrimal tear drainage.

Results:

A total of 26 patients with a mean age of 43.5

The pre-ocular tear film-air interface is the principle refractive surface of the eye. The maintenance of stable quality tear film is of paramount importance with regard to good vision. Tear film consists of three layers. The most superficial layer of tear film is lipid layer, 0.11 µm thick produced by the meibomian glands. It serves to retard evaporation, allows smooth movements of the lids, prevents contamination of the tear film, and thickens and stabilizes the tear film. The middle layer the widest at 7.0 µm is the aqueous layer produced by the main lacrimal gland as well as accessory lacrimal glands of Krause and Wolfring. Aqueous tear deficiency is the most common cause of dry eye. Aqueous layer constitutes over 90% of tear film. The layer closest to the cornea is the mucin layer 0.02-0.05 µm thick, produced by conjunctival goblet cells. Mucin layer lowers tear's surface tension and forms loose adsorptive coating rendering the corneal and conjunctival surfaces wettable (1). Each layer of tear film can be affected by different diseases, each causing clinically dry eye or keratoconjunctivitis sicca

Healthy eyes are covered with a fluid all the time, known as a tear film, which is designed to remain stable between each blink. A stable tear film prevents the eyes from becoming dry, and keeps the eyes clear, and with comfortable vision. If the tear glands produce a lower quantity of tears, the tear film can become destabilized. The tear film can break down quickly, creating dry spots on the surface of the eyes (3, 4).

Dry eye syndrome can occur at any age, and in people who are otherwise healthy. It is more common with older age, when the individual produces fewer tears. In some parts of the world, where malnutrition results in a vitamin A deficiency, dry eye syndrome is much more common (5). The proper balance of oil, water, and mucus must be maintained to allow tears to lubricate and protect your eyes. Deficiency in any of these components can lead to eyes becoming dry and irritated. If high-quality tears are not produced at a steady rate, the surface of your eyes becomes irritated and your eyes will tear excessively in an attempt to lubricate them. This is why excess tearing can occur from dry eyes