Using Toric Soft Lenses for Postsurgical Astigmatism

BY ROBERT CAMPBELL, M.D. & PATRICK CAROLINE, C.O.T., F.A.A.O.
NOV. 1996

Patient E.B. is a 27-year-old man who suffered a ruptured globe, multiple corneal lacerations and traumatic aphakia to the left eye on Aug. 16, 1994. He had surgery that day for primary closure of the lacerations, excision and repositioning of the exposed uvea and removal of the lens cortex. He returned to surgery on Aug. 22 for secondary wound repair, removal of the remaining lens and vitrectomy with fluid/gas exchange (Fig. 1).

FIG. 1: CORNEAL LACERATION CAUSED BY 1/4" GALVANIZED CABLE.

FIG. 2: PHOTOKERATOSCOPY EIGHT MONTHS POST TRAUMA.

FIG. 3: PENETRATING KERATOPLASTY TO REMOVE CORNEAL SCARS.

Eight months post injury, we evaluated E.B. for an aphakic RGP correction of the left eye. Photokeratoscopy revealed significant central and mid-peripheral irregular astigmatism and scarring (Fig. 2). An RGP lens was fitted base curve 43.00D, power +11.00D, diameter 10.4mm, anterior optic zone 9.0mm. He tolerated the lens well, but best corrected visual acuity was 20/60.

On April 5, 1995, E.B. underwent corneal transplant surgery to remove the traumatic scar. The postoperative course was unremarkable and we once again evaluated him for contact lens correction (Fig. 3). Photokeratoscopy nine months after surgery revealed moderate, with-the-rule, regular astigmatism (Fig. 4). Central keratometry was 41.25 @ 005: 43.50 @ 095 and the resultant manifest refraction was +13.75 -3.75 x 178, 20/25. We prescribed a Flexlens 55 custom toric soft contact lens.

POST-PK CORRECTION

Toric soft contact lenses can be successfully fitted after penetrating keratoplasty. Special attention should be directed to the metabolic requirements of the host and the donor tissues to avoid corneal hypoxia and neovascularization, especially in the ballast area where the lens is thickest. Optically, a spherocylinder overrefraction is often required after the patient has adapted.

In this month's case, the original toric soft contact lens was: base curve 8.6, power +15.00 -3.00 x 180, diameter 15.0mm. Visual acuity was 20/70. A spherocylinder overrefraction of +2.75 -1.25 x 175 resulted in a visual acuity of 20/20. The new lens was 8.6 +17.75 -4.00 x 178 15.0 with a final visual acuity of 20/20 (Fig. 5).

FIG. 4: PHOTOKERATOSCOPY NINE MONTHS POST KERATOPLASTY.

FIG. 5: CUSTOM TORIC SOFT CONTACT LENS POST KERATOPLASTY.

Dr. Campbell is medical director of the Park Nicollet Contact Lens Clinic & Research Center, Minnetonka, Minn. Patrick Caroline is an assistant professor of optometry at Pacific University, Forest Grove, Ore., and director of contact lens research at Oregon Health Sciences University in Portland.