10
Intracapsular Cataract Extraction/Anterior Chamber Intraocular Lens

See Chapter 3.

1. Examine anterior chamber angle with a gonioscope to inspect for peripheral anterior synechiae (PAS) or other abnormalities that may interfere with or preclude implantation of anterior chamber intraocular lens (IOL).

2. Calculate IOL power.

Numerous formulas for the calculation of IOL power have been derived based on both theoretical optics and empirical data. The Sanders-Retzlaff-Kraff (SRK) formula is one of the most widely used.

SRK Formula: Power of IOL = A—2.5(AL)—0.9(K) where

a. A = constant is determined by the manufacturer of a specific lens. A typical value is A = 116.7.

b. K = average keratometry measurement in diopters.

c. AL = axial length of eye in millimeters measured with A-scan ultrasonography.

3. Determine target postoperative refraction.

4. Dilate pupil: Tropicamide 1%, phenylephrine 2.5%, and Cyclogyl 1% every 15 minutes starting 1 hour before surgery.

5. Preoperative drop of antibiotic (e.g., moxifloxacin 0.5% [Vigamox, Alcon, Inc., Fort Worth, TX, US], gatifloxacin 0.3% [Zymar, Allergan, Inc., Irvine, CA, US]) 1 drop before surgery.

6. Optional: Topical nonsteroidal anti-inflammatory agent every 15 minutes starting 1 hour before surgery (to minimize intraoperative miosis).

7. Optional: Topical nonsteroidal anti-inflammatory agent (NSAID) (e.g., nepafenac 0.1% [Nevanac, Alcon, Inc.] 3 times per day, ketorolac tromethamine [Acular, Allergan, Inc.] 4 times per day, or bromfenac ophthalmic solution 0.009% [Xibrom, ISTA, Inc., Alpharetta, GA, US] 2 times per day), for 5–7 days before surgery suggested for diabetics and then for ~3 months after surgery to help prevent cystoid macular edema. This is also suggested for stable uveitic patients who have shown no inflammation for 3 months before surgery. Consider admitting patient 1 day before surgery for intravenous steroid if active uveitis is present. Check literature for updated efficacy studies among topical NSAIDs as indicated.

8. Optional: Treat patient with a hyperosmotic agent to dehydrate vitreous and minimize positive vitreous pressure. The following may be used:

a. Mannitol 20%, 1–2 g/kg IV given over 1 hour, 90 minutes preoperative.

b. Mannitol 25%, 50 ml IV push given just before surgery.

Instrumentation

Honan balloon

Lid speculum

Castroviejo calipers

Fine-toothed forceps (e.g., 0.12 mm straight Castroviejo and/or Colibri)

Sutures (4–0 silk, 8–0 and 10–0 Vicryl, 10–0 nylon)

Elschnig forceps

Kalt needle holder

Fine needle holder

Westcott scissors

Cellulose sponges

Cautery (underwater eraser or disposable)

Scleral incision blade (Beaver #64 or #69)

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

Left- and right-handed corneoscleral scissors

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