44
Goniotomy and Trabeculotomy

See Chapter 3.

1. Treatment of primary congenital glaucoma is usually surgical. Medical therapy is usually a temporizing measure before surgery.

2. Educate the parents about the possibility of multiple operations and frequent follow-up visits.

3. Perform a thorough preoperative examination of the patient in the office. Intraocular pressure (IOP) should be accurately determined in the office, as many drugs used during an examination under anesthesia alter the IOP.

4. Rule out nasolacrimal duct obstruction as a cause of epiphora.

5. Clear as much corneal edema as possible with medical treatment to lower the eye pressure. Use oral acetazolamide if needed. Goniotomy can be done with greater accuracy through a clearer cornea.

6. Apply a topical antibiotic ointment to both eyes the evening before surgery.

7. As long as an accurate eye pressure has already been obtained, a drop of 1% pilocarpine 30 minutes prior to surgery will protect the lens from the goniotomy knife.

Instrumentation

Pilocarpine 1% (optional)

Antibiotic ointment

Proparacaine hydrochloride

Alcohol containing red dye

Handheld tonometer (e.g., Perkins)

Calipers

Koeppe gonioscopy lens

Handheld microscope

Barkan handheld light

Direct ophthalmoscope

No. 15 Bard-Parker blade

Binocular loupes

Headlight or operating microscope

Lid speculum

Elschnig-O’Connor locking fixation forceps

Castroviejo 0.3 mm forceps

Muscle hook

Barkan operating gonioscopy lens, small and large

Goniotomy knife (nontapered Swan, tapered Swan, or Barkan) (Fig. 44.1). (Note that the figure shows these knives in this order, from left to right.)

Balanced salt solution (BSS)

5. If the cornea is cloudy, a drop of proparacaine is place on the eye. A small amount of alcohol is painted over approximately one fourth of the cornea, 180 degrees away from the side of the angle to undergo goniotomy. After 10 seconds, the alcohol is irrigated away, and the epithelium is scraped away with a #15 Bard-Parker blade (Fig. 44.2). Care should be taken to preserve the limbal epithelial cells.

6. Prep and drape.

7. The surgeon is positioned to face the angle where the surgery will be performed.

8. The assistant will be opposite the surgeon.

9. Place the lid speculum.

10. Fixation of the eye:

a. Castroviejo forceps are used to grab the conjunctiva near the limbus at 6 o’clock, and the eye is infra-ducted (Fig. 44.3). A muscle hook can alternatively be used to infraduct the eye.

b. Elschnig-O’Connor locking fixation forceps are used to lock the superior rectus.

c. The eye is then supraducted.

d. The other Elschnig-O’Connor locking fixation forceps are used to lock the inferior rectus.

e. The lid speculum is removed.

f. The two locking fixation forceps are handed to the assistant to position the globe.

11. Positioning of the head:

a. The patient’s head is tilted 30 degrees away from the surgeon (Fig. 44.4). This facilitates the surgery and more easily allows removal of any air bubbles under the lens.

b. Barkan gonioscopy lens is placed on the cornea (Figs. 44.5 and 44.6). BSS is placed under the lens. Optional: Use Goniosol with lens.

12. Entry of the goniotomy knife into the anterior chamber.

a. The assistant may need to provide a slow and almost imperceptible movement of the eye toward the knife as it enters the eye to provide some counterresistance as the entered knife may push the eye away from the surgeon.

b. The knife starts to enter the anterior chamber through the cornea ~1 mm from the limbus. The entry site is 180 degrees away from the center of the area of angle to have surgery (Fig. 44.7).

c. As the knife passes through the cornea, the surgeon should shift his or her view through the Barkan operating lens. The knife should be seen entering the anterior chamber.

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