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Combined Penetrating Keratoplasty/Extracapsular Cataract Extraction/Posterior Chamber Intraocular Lens

See Chapters 3 and 9.

Calculate intraocular lens (IOL) power using Sanders-Retzlaff-Kraff (SRK II) formula:

Power of IOL = A − 2.5(AL) − 0.9(K), where:

A-constant (A) is determined by the manufacturer for a specific lens. A typical value for a posterior chamber lens is 118.4.

Axial length (AL) of eye in millimeters.

Keratometry measurement (K) cannot be directly determined preoperatively.

The surgeon may use past postoperative keratometry results obtained with a specific technique as an approximate K reading.

The curvature of the normal fellow cornea may be measured and used in the SRK formula. When using a 0.5 mm oversized graft, however, subtract 1 to 2 diopters from the SRK result as the graft is typically steeper than the original cornea.

Dilate Pupil

1. Cyclopentolate 1%, phenylephrine 2.5%, and tropicamide 1% every 15 minutes beginning 1 hour before surgery.

2. Optional: Topical nonsteroidal anti-inflammatory agent (e.g., flurbiprofen 0.3% [Ocufen, Allergan, Inc., Irvine, CA, US]) every 30 minutes beginning 2 hours before surgery to minimize intraoperative miosis.

3. Optional: Preoperative antibiotic drops (e.g., moxifloxacin 0.5% [Vigamox, Alcon Laboratories, Inc., Fort Worth, TX, US], gatifloxacin 0.3% [Zymar, Allergan, Inc.]) every 15 minutes for a total of 3 drops may be used as prophylaxis.

Instrumentation

Honan balloon

Mannitol 20% solution

0.12 mm straight Castroviejo forceps

0.12 mm Colibri forceps

Bishop-Harmon forceps

Teflon cutting block

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

Cellulose sponges

Speculum (e.g., Lieberman or Barraquer)

Kalt or other strong needle holder

Fine nonlocking needle holder

Flieringa ring

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

Hemostats

Radial keratotomy marker

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

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

Cautery

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

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

Corneal scissors (right and left)

Cystotome

Cyclodialysis spatula

Lens loop

Kuglen hook

IOL forceps

Muscle hook

Sinskey hook

4. Trephine donor button from corneoscleral rim (Fig. 16.1).

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 the trephination (cellulose sponges).

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

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

Note: An 8.0 mm 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 motion through the entire donor thickness to avoid beveling the edge (listen for “crunch” sound).

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