15
Penetrating Keratoplasty

See Chapter 3.

Pupil Management

1. Phakic eye

Pilocarpine 1% every 15 minutes beginning 1 hour before surgery for a total of three drops to produce miosis, which protects lens during surgery. Alternatively, intraoperative acetylcholine (Miochol) may be used.

2. Aphakic eye

a. If anterior vitrectomy is anticipated, it may be facilitated by preoperative pupil dilatation (e.g., tropicamide 1%, cyclopentolate 1% and phenylephrine 2.5% every 15 minutes beginning 1 hour before surgery).

b. If a vitrectomy is not planned, preoperative dilation or constriction is unnecessary.

Instrumentation

Honan balloon

Mannitol 20% solution

Speculum (Lieberman or Barraquer)

Fine tissue forceps (e.g., 0.12 mm straight Castroviejo, 0.12 Colibri, Pierse)

Bishop-Harmon forceps

Teflon cutting block

Cellulose sponges

Disposable trephine (e.g., Katena, Storz, Weck)

Vacuum trephine (e.g., Hessburg-Barron)

Sutures (7–0 Vicryl, 4–0 silk, 10–0 nylon)

Kalt or other strong needle holder

Fine nonlocking needle holder

Radial keratotomy (RK) marker

Marking pen (e.g., methylene blue, gentian violet)

Cautery

Microsurgical knife (e.g., Superblade, 15 degree, Beaver #75M)

Viscoelastic substance (e.g., Healon, Amvisc, Viscoat)

Corneal scissors (right and left)

Paton corneal spatula

Vannas scissors

Westcott scissors

Intraocular lens (IOL) scissors

McPherson tying forceps

Cyclodialysis spatula

Flieringa scleral ring

Hemostats

Jeweler’s forceps

Microvitrectomy suction/cutting instrumentation

Acetylcholine solution (e.g., Miochol)

Operative Procedure

4. Trephine donor button from corneoscleral rim (Fig. 15.1).

Note: Secure a sterile work area with comfortable surgeon access and adequate lighting, away from the surgical instruments and patient (e.g., work table with stool)

a. Hold corneoscleral rim with toothed forceps (e.g., Bishop-Harmon).

b. Remove residual fluid from epithelial side of donor to avoid sliding during trephination (cellulose sponges).

c. Place donor tissue epithelial side down (endothelial side up) and center on Teflon cutting block.

d. Trephine appropriately sized button (disposable trephine on universal handle).

Note: An 8.0 mm donor button placed into a 7.5 mm recipient bed is a standard size differential.

  i. Keep trephine perpendicular to cornea.

 ii. Punch button in one fluid motion through entire donor thickness to avoid beveling the edge (listen for “crunch” sound).

iii. May use guillotine-style trephine to better control trephination.

e. Before removing trephine, ensure that the cut is through full-thickness cornea by gently raising the remaining scleral rim from the cutting block with toothed forceps, leaving the donor button behind.

f. Remove trephine.

g. Place a few drops of storage medium on the endothelial side of the button and cover the block to prevent drying of the donor.

h. Keep corneal donor on work table in secure location and inform all operating room staff.

i. Send corneoscleral rim and storage media for culture.

5. Return attention to the patient’s eye.

6. Insert lid speculum, attempting to minimize pressure against globe from lid speculum.

a. Optional: Place 4–0 silk bridle sutures.

7. Secure Flieringa ring (Fig. 15.2).

a. Choose ring size to leave ~2–3 mm between the ring and limbus.

b. Secure globe with toothed forceps.

c. Secure ring using four to eight equally spaced interrupted 7–0 Vicryl sutures.

d. Place sutures through conjunctiva and episclera.

e. Tie all sutures to equal tension to avoid distortion of globe.

Note: A Flieringa ring is not necessary in phakic keratoplasty, unless there is a possibility of lens removal at the time of surgery.

8. Optional: Mark cardinal positions and center of trephination on the recipient with a radial keratotomy marker and dye (gentian violet or methylene blue).

Stay updated, free articles. Join our Telegram channel

Join