Nonmechanical corneal trephination with the excimer laser improves outcome after penetrating keratoplasty.

Abstract

OBJECTIVE:

To assess the impact of nonmechanical trephination on the outcome after penetrating keratoplasty (PK).

DESIGN:

Prospective, randomized, cross-sectional, clinical, single-center study.

PATIENTS:

A total of 179 eyes of 76 females and 103 males, mean age at the time of surgery 50.6 +/- 18.5 (range, 15-83) years. Inclusion criteria were (1) time interval from October 1992 to December 1997; (2) one surgeon (GOHN); (3) primary central PK; (4) Fuchs dystrophy (diameter, 7.5 mm) or keratoconus (diameter, 8.0 mm); (5) graft oversize, 0.1 mm; (6) no previous intraocular surgery; and (7) 16-bite double-running diagonal suture.

INTERVENTION:

In a randomized fashion, eyes were assigned either to trephination with the 193-nm Meditec excimer laser (manually guided beam in patients, automated rotation device of artificial anterior chamber in donors) along metal masks with eight orientation teeth/notches (EXCIMER: 53 keratoconus, 35 Fuchs dystrophy; mean follow-up, 37 +/- 16 months) or with a hand-held motor trephine (Microkeratron; Geuder) (

CONTROL:

53 keratoconus, 38 Fuchs dystrophy; mean follow-up, 38 +/- 14 months). Subjective refractometry (trial glasses), standard keratometry (Zeiss), and corneal topography analysis (TMS-1; Tomey) were performed before surgery, before removal of the first suture (15.2 +/- 4.2 months), and after removal of the second suture (21.4 +/- 5.6 months).

MAIN OUTCOME MEASURES:

Keratometric and topographic net astigmatism as well as refractive cylinder; keratometric and topographic central power; best-corrected visual acuity (VA); surface regularity index (SRI), surface asymmetry index (SAI), and potential visual acuity (PVA) of the TMS-1.

RESULTS:

Before suture removal, mean refractive/keratometric/topographic astigmatism did not differ significantly between EXCIMER (2.5 +/- 1.8 diopters [D]/3.4 +/- 2.8 D/4.7 +/- 3.1 D) and CONTROL groups (3.0 +/- 1.8 D/3.7 +/- 2.4 D/4.3 +/- 2.1 D). After suture removal, respective values were significantly lower in the EXCIMER group (2.8 +/- 2.0 D/3.0 +/- 2.1 D/3.8 +/- 2.6 D) than in the CONTROL group (4.2 +/- 2.4 D/6.1 +/- 2.7 D/6.7 +/- 3.1 D) (P < 0.0009). In the EXCIMER versus CONTROL group, mean VA increased from 20/100 versus 20/111 (P > 0.05) before surgery, to 20/31 versus 20/38 before (P = 0.001) and to 20/28 versus 20/39 (P < 0.00001) after suture removal. Mean spherical equivalent was significantly less myopic in the EXCIMER group before (-0.9 +/- 3.6 D vs. -2.6 +/- 3.4 D) (P = 0.01) and after suture removal (-1.4 +/- 3.1 D vs. -2.4 +/- 3.5 D) (P = 0.02). Mean SRI (P = 0.04) and PVA (P = 0.007) were significantly more favorable in the EXCIMER versus CONTROL group after suture removal (0.91 +/- 0.45 and 0.82 +/- 0.15 vs. 1.05 +/- 0.46 and 0.73 +/- 0.18).

CONCLUSIONS:

Postkeratoplasty results seem to be superior using nonmechanical excimer laser trephination. Thus, this methodology is recommended as the procedure of first choice in avascular corneal pathologies requiring PK.

• Authors: B Seitz, A Langenbucher, M M Kus, M Küchle, G O Naumann
• Journal: Ophthalmology (Ophthalmology) Vol. 106 Issue 6 Pg. 1156-64; discussion 1165 (Jun 1999) ISSN: 0161-6420 [Print] United States
• PMID: 10366086 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Astigmatism (prevention & control)
• Cornea (surgery)
• Corneal Diseases (surgery)
• Corneal Topography
• Cross-Sectional Studies
• Double-Blind Method
• Female
• Humans
• Keratoplasty, Penetrating (methods)
• Lasers, Excimer
• Male
• Middle Aged
• Photorefractive Keratectomy
• Prospective Studies
• Refraction, Ocular
• Tissue Donors
• Treatment Outcome
• Visual Acuity