1-10. PROCEDURES ON LACRIMAL APPARATUS (TEAR-DUCT SYSTEM)
a. Dacryocystectomy. A dacryocyst is a lacrimal (tear) sac. Therefore,
dacryocystectomy is excision of the wall of the lacrimal sac. It is indicated as treatment
for acute dacryocystitis. A lump may appear under the skin at the inner corner of the
eye as the tear sac fills with pus. If the pus cannot be discharged from the sac by
pressing on it, the ducts may be blocked and surgical incision and drainage of the sac is
required to relieve the condition.
b. Dacryocystorhinostomy. This is the construction of an opening from the
tear sac into the nasal cavity. The surgery may be done as treatment for chronic
dacryocystitis, trauma to the nasolacrimal duct, or congenital malformation of the duct.
In children, early probing of the nasolacrimal duct (before age of 1) may prevent the
need for a dacryocystorhinostomy later.
1-11. PROCEDURES ON EXTRAOCULAR MUSCLES
a. General. Operations on muscles outside the eyeball are done for correction
of strabismus. Strabismus is a term describing muscle imbalance between two eyes.
An eye deviating outward or away from its fellow eye is a condition termed exotropia. If
the eye deviates inward, it is termed esotropia.
b. Objective of Surgery.
To secure binocular single vision by performing accurate binocular
(2) To achieve alignment that allows the best possible cosmetic effect and
enables maintenance of the effect for as long as possible.
c. Kinds of Operations. Strabismus may be treated surgically by procedures
done either to strengthen weak muscles (refer to paragraphs 1-11d, e, and f below) or
to weaken overactive muscles (refer to paragraphs g and h below).
d. Tucking. A tuck is sutured in the muscle, thus shortening it and increasing its
e. Advancement. The muscle is freed at its attachment point, and it is
reattached closer to the cornea, thus increasing its leverage.
f. Resection (Shortening). Part of the tendon of a extraocular muscle is
excised. The muscle is reattached to the sclera at the original point of insertion.
g. Tenotomy. This is transection of the muscle sheath and tendon.
h. Recession (Lengthening). The muscle is detached from the eyeball and is
sutured to the sclera posterior to the original insertion.