Watering of the eyes sometimes becomes a very annoying symptom to a person and occasionally a problem to the attending physician to give relief to his patient.
The commonest causes may be roughly classified as follows:-
1. Local causes:- The commonest of them are the diseases affecting the epithelial coating of the surface of the eyeball and the lids known as conjunctiva, the nature of which may be –
(a) Bacterial infection in its early stages.
(b) Irritation by foreign bodies falling on it including dust, insects, coal particles, wooden and metallic particles, etc.
(c) Exposure to smokes, fumes of acids and alkalies and other forms of gaseous emanations.
(d) Glare from light falling directly or lights reflected from snow, glaciers, etc.
2. Reflex or referred causes: The sensory nerve supply of the eye is from ophthalmic division of the trigeminal nerve, whose branches besides the eye, also supply the teeth of both upper and lower jaw by its maxillary and mandibular division. It also supplies branches to the supraorbital region, face and nose. Thus any trouble involving any one of these branches reflexly causes irritation and as a consequence watering of the eyes.
The trochlear nerve supplying the lachrymal glands if stimulated reflexly by any psychic conditions such as extreme sorrow or extreme joy, etc.
All diseases of the cornea, iris, retina and optic nerve cause reflex irritation and watering of the eyes.
3. Refractive causes: – Ordinarily the power of the ciliary muscles involved in accommodation to see objects at different distances are available without producing any ocular symptoms, but in any abnormal conditions of refractive errors such as: (a) Hypermetropia (commonly known as long sightedness);
(b) Astigmatism – defect in the curvature of the curved surfaces of the eye, being different in different meridians;
(c) Anisometropia – where the amount of refractive errors are different in two eyes;
(d) Presbyopia – here the lens in the eyes fail to undergo the required amount of changes necessary to see near object comfortably by the accommodative power exerted by the ciliary muscles, generally known as changes due to old age coming roughly at about 40 amongst Indians.
4. Secondary to diseases of the nose and the bony air sinuses around the orbital cavities. As most of the eye specialists in this country and also of Great Britain whom we generally follow make special study of the diseases of the eye alone, they very often overlook this aspect of the watering of the eyes and fail to give relief to their patients by the usual eye drops.
The Americans who are the most practical nation in the world have realised its importance long ago and in America the specialists always combine ophthalmic knowledge with the specialised knowledge of the diseases of the ear, nose and throat.
Any disease of the nasal air passages either affecting its mucus lining or growths such as nasal polypus and fibroids, etc., can obstruct the naso – lachrymal ducts, thus the free flow of the lachrymal secretion to the normal route to the nose is obstructed causing epiphora (overflow of the tear on the face) and also the infection finds its way upwards from the nose to the eyes causing lachrymation due to bacterial action.