Part 43 (1/2)

(_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.