Extracapsular Cataract Extraction

9
Extracapsular Cataract Extraction

Indications

Visually significant cataract impairing patient’s lifestyle.

Dense cataract obstructing view of fundus.

Possible advantages of extracapsular over phacoemulsification cataract surgery:

Reduced incidence of corneal decompensation in patients with corneal compromise.

Ease of removal of hard nucleus.

Preoperative Procedure

See Chapter 3.

1. Calculate intraocular lens (IOL) power.

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

3. 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 = 118.4

b. K = average keratometry measurement in diopters.

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

4. Determine target postoperative refraction:

a. Target postoperative refraction decisions depend on numerous factors, including patients’ desire for good vision for near or distance, eye dominance, refractive and lens status of the other eye, and the type of IOL planned (multifocal, new-generation refractive lenses).

b. Communication with the patient regarding refractive options assists in choosing appropriate targets.

5. Dilate pupil and preoperative drops:

a. Tropicamide 1%, phenylephrine 2.5%, and Cyclogyl 1%, every 15 minutes starting 1 hour before surgery is a typical regimen. Other regimen examples: Phen/Trop 1 gtt q 5 minutes × three. Coll 3&38 ¼ 1 gtt q 5 minutes × 3.

b. 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.

c. Optional: Topical nonsteroidal anti-inflammatory drug (NSAID) 1 drop every 15 minutes × 3 starting 1 hour before surgery (to minimize intraoperative miosis) (e.g., flurbiprofen 0.03% 1 gtt q 5 minutes × 2). Other topical 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) can be used for 5–7 days before surgery in patients with a history of diabetes, uveitis, previous cystoid macular edema, epiretinal membrane, or vein occlusion, and then for approximately 3 months after surgery to help prevent cystoid macular edema. Some surgeons use preoperative and postoperative NSAIDS on all patients. Check literature for updated efficacy studies among topical NSAIDs and current practices as indicated.

d. The use of preoperative (days before surgery) and intraoperative antibiotic use (diluted in balanced salt solution [BSS] bottle: vancomycin 1 mg/0.1ml balanced salt solution; intracameral cefuroxime: 1 mg cefuroxime in 0.1 ml saline 0.9%; intracameral moxifloxacin 100 μg/0.1 ml [1:5 dilution of moxifloxacin with BSS]) is controversial in terms of its proven benefit. Their use varies widely. Check the literature for updated information.

e. A commonly used regimen is the use of preoperative “pulse” antibiotics: fourth-generation fluoroquinolone used every 10 minutes times 4 doses 1hour before surgery. A fourth-generation fluoroquinolone is then used immediately after surgery and then continued during postoperative week 1 (e.g., moxifloxacin 0.5% [Vigamox, Alcon, Inc.], gatifloxacin 0.3% [Zymar, Allergan, Inc.]).

6. Recommended:

Use PMMA or acrylic lenses for patients with diabetes, uveitis, or glaucoma.