[Minimally inflammatory cataract surgery]

Abstract

Background: Cataract surgery leads to a more or less intensive postoperative inflammation due to breakdown of the blood-aqueous barrier. In a prospective, randomized and controlled clinical trial, we examined aqueous flare as well as intraocular pressure and visual acuity after a minimally invasive cataract surgical procedure under different anti-inflammatory treatment.

Patients and method: In 150 patients (39-88 years of age) without glaucoma or pre-existing deficiencies of the blood-aqueous barrier, phacoemulsification through a clear-corneal tunnel incision with implantation of a 5 mm PMMA posterior chamber intraocular lens was performed. Patients were randomly assigned to one of 5 treatment groups, each consisting of 30 patients: 1) preservative-free diclofenac 0.1% eyedrops (DICpf) pre- and postop.; 2) diclofenac 0.1% eyedrops with preservative (DICp) pre- and postop.; 3) DICpf only postop.; 4) DICpf pre- and postop. in combination with dexamethasone-21-dihydrogenphosphate 0.1% eyedrops (DEXA); 5) DEXA postoperatively. For prevention of postoperative intraocular pressure (IOP) elevation, carbachol 0.01% (for intraocular application) was injected into the anterior chamber intraoperatively, and dichlorphenamide (50 mg/d per os) was applied until day 1 postoperatively. - Aqueous flare (laser flare-cell meter FC-1000), IOP (Gold-mann applanation tonometer) and best-corrected visual acuity were determined on the day before surgery as well as 6 hrs (only flare and IOP), 1 day, 3 and 7 days postoperatively.

Results: Aqueous flare (photon counts/ms) in treatment group 1 increased from 10.8 +/- 1.7 (means +/- SE) preoperatively to only 14.7 +/- 3.1 in the afternoon of the day of surgery. Already on day 1 postoperatively, the flare decreased to 9.3 +/- 0.9, and remained relatively constant on days 3 and 7 after surgery. The flare in group 3 (DICpf only postop.) was significantly higher (p = 0.03; ANOVA) than in group 1. There were no other significant group differences concerning flare (group 1 vs. 3;1 vs. 4;4 vs. 5). -IOP (mm Hg) dropped from 16.3 +/- 0.2 preoperatively to 15.8 +/- 0.6 already 6 hrs postoperatively (group means). On days 1 and 3, the IOP continued to drop to 13.2 +/- 0.3 and 12.7 +/- 0.3, respectively. Not before day 7, the IOP tended to increase again (14.2 +/- 0.3). The IOP showed no significant group differences. - Visual acuity increased from 0.25 +/- 0.01 preoperatively to 0.73 +/- 0.02 already on day 1 postoperatively (group means). On days 3 and 7, the acuity amounted to 0.83 +/- 0.24 and 0.92 +/- 0.02, respectively.

Discussion: Under the conditions of the present study (with specific pharmacological therapy and patient selection), clear-corneal phacoemulsification leads to an extremely low and short-lasting intraocular inflammation, especially under pre- and postoperative treatment with preservative-free diclofenac eyedrops. Thus, the aim of minimally inflammatory cataract surgery (MICS) is realized. As secondary phenomenon, a postoperative IOP increase, often observed in the early postoperative period, is lacking, and the visual acuity rises very fast postoperatively.