Part 39 (1/2)

=Instruments.= Speculum, fixation forceps, a spoon which should have rather a blunt edge.

=Operation.= Under cocaine. The area is very lightly sc.r.a.ped with the spoon. The calcareous changes are in the deeper layers of the epithelium and Bowman's membrane and hence are easily removed. The sc.r.a.ping should be carried well beyond the apparent margin of the film. The epithelium often takes some time to regenerate. As a rule the results are satisfactory, although the film is apt to recur in the course of years, but it may be removed again if necessary.

OPERATIONS UPON THE CONJUNCTIVA

THE REMOVAL OF FOREIGN BODIES

Foreign bodies lodged in the conjunctival sac, unless embedded in the conjunctiva, are usually found by the surgeon under the upper lid, the sulcus subtarsalis being a favourite situation. They are easily removed with a spud or needle, after the instillation of a drop of 4% cocaine solution. Subsequently the eye should be bandaged for a few hours until the effect of the cocaine has pa.s.sed off, as in wiping the eye the patient may wipe off the epithelium of the cornea whilst it is insensitive from the cocaine.

_In order to evert the upper lid_ the patient is made to look strongly down, the eyelashes are seized between the thumb and forefinger of the left hand, the skin of the upper lid is pushed down above the tarsal cartilage with the thumb of the right hand, and the lid is everted by pulling it upwards against the point of the thumb.

OPERATION FOR PTERYGIUM

=Indications.= Pterygium should be removed when advancing across the cornea, especially when the pupillary area is becoming involved. The operation of ablation is the one now generally in use.

=Instruments.= Speculum, straight iris forceps, small sharp-pointed scissors.

=Operation.= Under adrenalin and cocaine the neck of the pterygium is seized with the forceps and the body and neck are carefully dissected from the conjunctiva. The body and neck should be very carefully separated right up to the corneal margin by means of forceps and scissors. The head is then stripped off the cornea with a sharp pull.

The wound in the conjunctiva should be subsequently closed with fine sutures, otherwise the disease will certainly recur. In stripping the head from the cornea some of the epithelium may be torn off with it.

This usually regenerates without impairing the vision.

EXPRESSION

This is an operation for the removal of follicular formations in the conjunctiva, and is used more especially in trachoma.

=Instruments.= Graddy's forceps (Fig. 129), fixation forceps.

=Operation.= The operation may be performed under cocaine and adrenalin, a little solid cocaine being rubbed into the area to be expressed. In severe cases in which both eyes are affected, and in small children, a general anaesthetic may be necessary.

Although a number of instruments are in use, perhaps the best, and certainly the least painful, is Graddy's forceps. In the case of the upper lid it is everted, one blade of the forceps being pa.s.sed into the fornix, the other being placed over the upper surface of the everted lid. A gentle steady pressure is applied, and the lid is drawn out between the blades. In this way as much of the conjunctiva is gone over as is necessary. The lower fornix is best expressed by picking up the loose fold of the fornix with ordinary forceps and then expressing with Graddy's.

[Ill.u.s.tration: FIG. 129. GRADDY'S FORCEPS.]

If only one or two follicles be present they can be picked up with the ordinary fine dissecting forceps and expressed, but when situated on the tarsus the follicles are best enucleated with a spud; a solution of 1 in 50 perchloride of mercury in glycerine is then rubbed into the conjunctiva. The operation may have to be repeated several times as new follicles form.

CONJUNCTIVOPLASTY

Conjunctivoplasty is an operation for the transplantation of a flap of conjunctiva to cover some loss of substance or defect in the continuity of the globe.

=Indications.= The operation may be necessary--

(i) To close large recent wounds of the cornea.

(ii) To close the wound made by the excision of a cystoid scar.