(_c_) _When the ca.n.a.liculus has been divided_ the end attached to the lachrymal sac should be sought for and divided for a short distance inwards from the wound (see p. 291), the entrance being kept open daily by a probe to prevent traumatic stricture.

OPERATIONS FOR ANKYLOBLEPHARON

Fusion of the eyelids together is either a congenital condition or the result of injury, and may take the form of bands or firm fibrous union.

It is rarely complete and is often a.s.sociated with symblepharon. The union should be divided on a director, or by careful dissection, taking care not to wound the underlying globe. The raw surfaces are kept apart by daily dressing until they are covered by epithelium. No externa[l]

dressing should be applied.

OPERATIONS FOR SYMBLEPHARON

_Partial adhesion of the lid to the globe_ in which a few bands pa.s.s from the lid to the globe are best treated by division followed by union of the ocular conjunctiva over the raw surface; no external dressing should be applied. Any tendency to fresh adhesion may be prevented by daily inspection.

_In extensive adhesion of the lid to the globe_, where the lids are entirely adherent to the globe and the cornea is destroyed, interference is inadvisable. In less extensive adhesion, the lid is first separated from the globe, reunion being prevented by covering the denuded area on the globe with a flap of bulbar conjunctiva transplanted from an area that does not come in contact with the raw surface on the eyelid (Teale's operation), or by Thiersch's grafts from a situation where there are no hairs; or by grafting mucous membrane from the mouth of the patient or a frog. Teale's operation, or some modification, is by far the most satisfactory, but unfortunately it cannot always be carried out when the loss of conjunctiva is large.

OPERATIONS UPON THE PALPEBRAL APERTURE

CANTHOPLASTY

=Indications.= In contraction of the palpebral aperture, either due to a congenital condition, or the result of a wound, trachoma, or other cicatricial contraction.

=Instruments.= Speculum, forceps, scissors, and three sutures.

=Operation.= The speculum is inserted and opened as widely as possible.

One blade of the scissors is pa.s.sed into the cul-de-sac at the outer angle of the lid and the palpebral aperture enlarged by dividing the outer canthus horizontally. The external tarsal ligament which is split longitudinally is then cut across with scissors pa.s.sed into the upper and lower wound. The conjunctiva is drawn up into the wound and st.i.tched to the skin at the margin to prevent reunion. The st.i.tches should be removed about the sixth day.

CANTHOTOMY

Canthotomy is simple division of the outer canthus without st.i.tching the conjunctiva into the wound. It is useful in some cases of blepharospasm a.s.sociated with fissure at the outer canthus.

CANTHORRHAPHY

Union of the eyelids, usually at the outer canthus.

=Indications.= (i) When the eyelids do not cover the globe as the result of--

(_a_) Cicatricial contraction of wounds, burns, &c., about the lid.

(_b_) Long-standing facial paralysis.

(_c_) Exophthalmic goitre.

(ii) To help maintain the lid in position after ectropion operations.

=Instruments.= Beer's knife, fixation forceps, spatula, and sutures.

=Operation.= _First step._ The position for the new external canthus is determined by holding the lids together at the outer canthus, and is marked on the upper and lower lids. From these points incisions are carried outwards to the external canthus along the intermarginal line in the top and bottom lids. These incisions are deepened to about 5 millimetres.

_Second step._ From the inner end of the incision in the lower lid a vertical one is made downwards for about 5 millimetres, and is then carried out to the external canthus. The tissue thus marked out, bearing the lashes, is then removed.

_Third step._ A corresponding, slightly larger, area is similarly removed from the under or conjunctival surface of the upper lid (Fig.

139).

[Ill.u.s.tration: FIG. 139. CANTHORRHAPHY.]

_Fourth step._ These two areas are brought into apposition by means of a strong suture pa.s.sed through their centre. The suture should have a needle at either end, and these should be pa.s.sed from the conjunctival surface and brought out through the middle of the raw area in the lower lid, about 2 millimetres apart, and then through the middle of the raw area in the upper lid and out through the skin. The suture is tied so that the two raw areas are brought into accurate apposition. The margins of the wound may then be brought together by sutures if necessary. The main suture should be left in for at least ten days.

TARSORRHAPHY

=Indications.= (i) Complete union of the eyelids may be required when an eye has been removed and for some reason an artificial one cannot be worn.

(ii) Partial union is effected in cases of paralysis of the first division of the fifth nerve when corneal ulceration threatens. A similar union is also useful in keeping the lower lid in position during the process of cicatrization in many of the operations for ectropion described below. The adhesions produced can be subsequently divided when contraction has ceased.

=Instruments.= Knife, forceps, scissors, spatula.

=Operation.= _Complete._ As narrow a strip of tissue as possible is removed from the lid borders behind the eyelashes. This is best performed by everting the upper lid and shaving off the posterior margin with a sharp knife; the lower lid is then treated similarly. The raw areas are brought into apposition with fine sutures.

_Partial._ When only a temporary adhesion is required, as after ectropion operations, it is sufficient to make raw corresponding areas of about 2 millimetres on the posterior margins of the top and bottom lids on either side of the central position of the cornea and unite them with sutures, which may be removed about the end of the first week.

PTOSIS OPERATIONS

The following operations are usually only undertaken for congenital ptosis, but they are occasionally required for the paralytic and traumatic varieties. All the operations are far from satisfactory, and should only be undertaken when the lid covers the pupil completely or so nearly that the head has to be thrown back to see objects directly in a line with the eyes. The relative value of the various operations apart from their indications is a matter of opinion amongst ophthalmic surgeons; therefore the various types of operations which are performed are given below.

There are four types of operation, which respectively aim at--

1. Shortening the eyelid by excision of a portion of the tarsal plate.

2. Attachment of the lid to the occipito-frontalis muscle.

3. Advancement of the levator palpebrae muscle.

4. Grafting of part of the superior rectus muscle into the lid to take the place of the levator palpebrae superioris.

SHORTENING THE EYELID BY EXCISION OF A PORTION OF THE TARSAL PLATE

=Fergus's operation (modified).= The object of this operation is to shorten the eyelid by removing the upper portion of the tarsal plate, the cut margin of which is subsequently sutured to the tendon of the levator palpebrae and the palpebral ligament.

The results of the operation are satisfactory, especially in cases in which there is some movement in the eyelid. The author, who has performed most of the ptosis operations on several occasions, has had most uniform results by this method, the modification of which was first suggested to him by Mr. Treacher Collins.

It has the advantage that the amount of retraction required may be more easily estimated, the corneal complications are of much rarer occurrence, and the resulting scar forms a natural fold in the lid. It is obviously not applicable to cases in which the eyelid is already short, as in the cases of 'Chinese eye' in which little can be done beyond enlarging the palpebral aperture.

=Instruments.= Spatula, scalpel, artery and dissecting forceps, scissors, and sutures.