Richard C. Troutman

Penetrating Keratoplasty for Keratoconus

A series of 86 penetrating keratoplasties for keratoconus were analyzed. The surgery, using an 8.2 mm donor cornea into an 8.0 mm recipient opening, was performed over the period January 1983 to January 1986 by one surgeon. The donor cornea was secured by two opposing continuous sutures, placed at full corneal thickness under surgical keratometry control. Both sutures were removed at an average 30 weeks after surgery. The mean postoperative sutures-out astigmatism was 5.4 diopters (range 0-19.0 diopters) and following secondary astigmatism surgery in 17 eyes, the mean group astigmatism was 4.3 diopters (range 0-10.5 diopters). Although graft reaction occurred in 11.6% of cases it was cleared medically and did not affect final vision results. One month after suture removal, with spectacle correction, 45.5% of the primary group saw 20/20, 90.7% 20/30 or better, and 97.7% 20/40 or better. Comparing these results with recently published data on epikeratophakia for the treatment of keratoconus, it is evident that penetrating keratoplasty offers these usually young patients a better chance for recovery of useful industrial acuity.

The Diagnostic Value of a Ring Infiltrate in Acanthamoebic Keratitis

During the past ten years it has become increasingly apparent that acanthamoebae can directly infect the cornea, usually after trauma, associated with contaminated water or soft contact lens wear. Thirteen cases of acanthamoebic keratitis have been published. In only three of these cases was the diagnosis first made by microbiologic methods, while in the others it was made only after pathologic examination of resected corneal specimens or enucleated eyes. We report three additional cases, two of which were accurately diagnosed by corneal scrape-smears and cultures before penetrating keratoplasty was performed. The reason for the accurate laboratory diagnosis in these cases was the presence of a diagnostic paracentral annular corneal infiltrate or abscess, a feature identified in over two-thirds of the earlier cases but one which has not been adequately emphasized or pursued for its early diagnostic value. We review the other clinical and epidemiological features of this entity, microbiological diagnostic techniques, the pathologic aspects, the role of topically and systemically administered medicaments, and finally point out the almost unavoidable role of penetrating keratoplasty after the temporizing effects of medical treatments have been achieved.

Astigmatism after penetrating keratoplasty using the Krumeich guided trephine system.

BACKGROUND The use of a suction trephine during penetrating keratoplasty has the potential to reduce trephination errors and astigmatism after suture removal. METHODS In this study, we evaluated refractive astigmatism after suture removal in 26 eyes that had penetrating keratoplasty for keratoconus using refraction, keratometry, and videokeratography. Group I (11 eyes) had manual trephination with an open disposable blade of both the donor (8.2 mm) and the recipient (8.0 mm). Group II (10 eyes) had manual trephination with an open disposable blade of the donor (8.2 mm) and Krumeich guided trephine system trephination of the recipient (8.0 mm). Group III (5 eyes) had guided trephination of both the donor (8.0 mm) and the recipient (8.0 mm). RESULTS The guided trephine groups II and III demonstrated statistically significant less refractive cylinder when compared to manual trephination group I (p < .01). The mean keratometric cylinder for group I was 6.50 diopters (D) (range, 1.50 to 9.00 D), for group II was 3.00 D (range, 0.50 to 7.00 D), and for group III was 2.55 D (range, 0 to 4.00 D). CONCLUSION The Krumeich guided trephine system produced less keratometric astigmatism than manual trephination after penetrating keratoplasty for keratoconus.

Combined Wedge Resection and Relaxing Incisions for Astigmatism After Penetrating Keratoplasty

BACKGROUND Videokeratography may provide information for surgical correction of astigmatism after penetrating keratoplasty. We used a combination of wedge resection and relaxing incisions to treat high refractive astigmatism after penetrating keratoplasty. METHODS Videokeratography using the normalized scale of the Topographic Modeling System was used as a guide in determining the location and the length of incisions and resections. Nine eyes were treated with both relaxing incisions and a wedge resection. All patients had more than 3.00 diopters (D) of refractive astigmatism. All patients were intolerant of spectacles or contact lenses. The depth of the corneal relaxing incisions was constant at 0.5 mm and the width of the corneal wedge resections was constant at 0.75 mm. RESULTS The relaxing incisions produced flattening of the steeper meridian and the wedge resection produced steepening of the flatter meridian. The average preoperative keratometric astigmatism was 7.44 D (range, 3.50 to 11.00 D) and the average refractive astigmatism was 5.56 D (range, 4.00 to 8.00 D). The average preoperative spherical equivalent was 0.08 D (range, -7.00 to 4.25 D). Postoperatively, the average keratometric astigmatism was 2.97 D (range, 1.00 to 5.00 D) and the average refractive astigmatism was 2.58 D (range, 0.00 to 5.00 D). The average postoperative spherical equivalent refraction was -0.32 D. CONCLUSIONS Combined corneal wedge resection and relaxing incisions appears to be effective in reducing high refractive astigmatism following corneal transplantation.

Placement of Sutures Used in Corneal Incisions

In monkey eyes, 10-0 monofilament nylon suture for corneal wound closure was placed deep to the level of Descemets membrane or through corneal tissue. The material produced a minimal inflammatory reaction and held the corneal wound in good anatomical position, effecting closure in depth.

A New Laser for Collagen Wounding in Corneal and Strabismus Surgery — A Preliminary Report

It has been shown that using a small spot size 2 to 5 mu, a dye modified excimer laser emitting at 595 nm can produce laser ablation of tissue in corneal stroma without compromising anterior and posterior limiting membranes. The surface of extraocular muscle tendon sheath has been similarly laser modified. An instrument, under prototype construction, designed for clinical application of this laser energy is described as well as clinical implications of such surgical interventions in corneal and extraocular muscle surgery.

Keratophakia???Postoperative Astigmatism

Forty-nine cases of primary keratophakia and 13 cases of secondary keratophakia were analyzed for postoperative astigmatism. For primary cases, the surgically induced astigmatism was 1.55 D, whereas for secondary cases it was 0.19 D (insignificant). There was a tendency for both procedures to induce against-the-rule astigmatism, and both procedures were found capable of producing irregular astigmatism.