A new scleral suction trephine for retrieval of corneoscleral donor tissue.

BACKGROUND: Removal of donor corneo-scleral shell from a cadaver, leaving the remainder of the eye in place, has become a popular technique. Manual removal can result in excessive trauma to the corneal endothelium or an uneven scleral rim. METHODS: We describe a new technique for corneal retrieval using a sceral suction trephine. RESULTS: The scleral suction trephine was cut evenly in our eyebank study. There was no additional trauma to the endothelium and the scleral rim was regular. CONCLUSION: Suction trephination of the sclera in retrieval of corneal donor tissue appears to be safe and effective.

Human excimer laser keratectomy. Clinical and histopathologic correlations.

PURPOSE: To understand the healing capabilities of the diseased human cornea after excimer laser photoablation by morphologic analysis of laser-treated corneas. METHODS: Twelve corneal specimens were obtained 5 to 16 months after lamellar or full-thickness keratoplasty following phototherapeutic keratectomy for undercorrected myopic epikeratoplasty (2 eyes), corneal leukomas (2 eyes), herpes zoster corneal scarring (1 eye), band keratopathy (2 eyes), adenoviral subepithelial opacity (1 eye), keratoconus (1 eye), herpes simplex corneal scarring (2 eyes), granular corneal dystrophy (1 eye), and recurrent lattice dystrophy (1 eye). The morphology of the corneas was examined by light and electron microscopy. RESULTS: Epithelial hyperplasia, abnormal epithelial attachment, and disorganized stromal matrices were observed. Evidence of residual disease frequently observed in these specimens indicated that the pathology either was not excised at the time of laser keratectomy or was recurrent. CONCLUSIONS: The response of the diseased cornea to excimer laser treatment has similar characteristics to the responses previously observed in animal studies. Incomplete ablation of diseased tissue and/or recurrence of the initial disease was the major reason for failure of the treatment. Possible causes for the inability to remove diseased tissues and superficial scars with the excimer laser include (1) insufficiently achieved ablation depth and/or diameter and (2) decreased laser ablation rates of scarred cornea.

Lamellar keratoplasty performed with a corneal scleral button.

Tissue for lamellar corneal surgical procedures is usually harvested from whole eyes. We describe a surgical technique for the rehabilitation of corneoscleral defects with lamellar keratoplasty in which the donor tissue is obtained from a preserved corneoscleral button instead of a whole globe. This technique is illustrated with a case involving the treatment of a limbal dermoid in a 26-month-old boy.

A surgical technique for the treatment of central corneal perforations.

BACKGROUND: Generally, corneal perforations of 2 mm in diameter or greater are treated using graft material for tectonic support. A surgical technique for the primary repair of such perforations without the use of any additional tissue is presented. METHODS: This procedure is demonstrated by a case report. The technique involves creation of an elliptical defect out of a circular one, thus allowing for primary closure, with the addition of glue. A definitive penetrating keratoplasty was subsequently performed with several important modifications described herein. RESULTS: A water-tight closure was obtained with this technique for 1 month while the inflammation subsided. Preoperative visual acuity was light perception. One year postoperatively, it was count fingers at 8 feet with mild irregular astigmatism. CONCLUSION: This technique is useful for perforations which are central, larger than 2 mm in diameter, and when corneal or scleral material is not readily available for patch grafting.

Electron microscopic findings in a cornea with recurrence of herpes simplex keratitis after excimer laser phototherapeutic keratectomy.

Excimer laser phototherapeutic keratectomy is emerging as an alternative therapy to corneal transplantation for the treatment of multiple corneal diseases. We report three cases of recurrence of herpes simplex keratitis after treatment of herpetic corneal scars with the excimer laser. In two cases, the patients underwent subsequent corneal transplantation. One corneal button examined with transmission electron microscopy (TEM) demonstrated a well-differentiated epithelium over the area of ablation, a linear, continuous basal lamina, and no viral particles. Anterior stromal scarring may have resulted from the laser treatment itself or may represent incomplete ablation of previous scars. Whether reactivation of the virus was stimulated by the laser or occurred as part of the natural history of the disease is uncertain. We recommend that patients who undergo excimer laser treatment for herpes simplex scarring receive careful follow-up including antiviral coverage.

A prospective, randomized comparison of thermal cautery and argon laser for permanent punctal occlusion.

Permanent punctal occlusion was performed by two techniques on 27 patients (73 puncta). Patients were randomly assigned to be treated with either thermal cautery or argon laser for keratitis sicca. Follow-up assessment disclosed that the puncta to which thermal cautery was applied remained closed significantly longer than those to which laser treatment was applied (P < .05, log-rank test). Using time to recanalization of a punctum as the end point, we found a long-term advantage of thermal cautery over argon laser treatment.

Arcuate keratotomy for the correction of spherical hyperopia in human cadaver eyes.

BACKGROUND: A new experimental surgical technique to correct spherical hyperopia by steepening of the central corneal curvature was performed on human cadaver eyes. METHODS: Ten eyes were used in the study. All were pretreated with glycerin to ensure a uniform corneal thickness between .55 and .65 mm on ultrasonic pachometry. A constant intraocular pressure of approximately 30 to 40 mm Hg was maintained in each eye by the injection of saline into the vitreous cavity. This was verified by pneumotonometry. A vertical blade diamond knife was set at 100% of the thinnest of four paracentral readings. Each eye underwent preoperative computed topography. One set of five eyes had 12 incisions made following a 5.75-millimeter diameter Mendez hexagonal marker that included unconnected T incisions at each junction (ie, "Hex T" pattern). The other set of five eyes had four arcuate incisions made following a 6-millimeter diameter zone marker; each incision was 60 degrees in arc. Immediately after surgery, computed topography was repeated. RESULTS: The hexagonal keratotomy set of eyes had an average steepening of the cornea of 0.80 D with a range of -1.05 to + 4.38 D. The arcuate keratotomy set had an average steepening of +2.12 D with a range of +1.27 to +3.27 D. CONCLUSIONS: This study suggests arcuate keratotomy may be a more effective procedure in the correction of spherical hyperopia when compared with hexagonal keratotomy. The amount of corneal steepening achieved in a cadaver eye model may not be the same as when performed in vivo.

Iowa PK Press for donor corneas--a comparative study of donor corneal shape.

BACKGROUND: A new cornea press for cutting donor corneal buttons from the endothelial side, the Iowa PK Press, is described. Major modifications of the Bourne Press include a spring-activated piston without lateral sway, a centering device for a Teflon cutting pad, and the ability to accommodate a wider range of trephine sizes (6.2 mm to 10.0 mm). METHODS: The Iowa PK Press was compared with the Bourne Corneal Press and trephination by hand in a series of 15 donor cornea trephinations. Measurements taken from photographs of the buttons included endothelial diameter, epithelial diameter, and edge angles. RESULTS: The Iowa PK press cut buttons that had a slightly larger epithelial and endothelial diameter when compared to hand trephination (p < .05, analysis of variance) with less undercutting of the endothelial surface. There was no statistically significant difference in epithelial and endothelial diameters, eccentricity, or edge angles between the two presses. CONCLUSIONS: The Iowa PK Press is more versatile than the Bourne Press in terms of the potential range of diameter of corneal buttons that can be created.

Elevated corneal epithelial lines in Acanthamoeba keratitis.

Elevated corneal epithelial lines are another clinical sign in Acanthamoeba corneal infection. In this report, one patient wore extended wear soft contact lenses, and another wore daily wear soft contact lenses. Both patients used distilled water and salt tablets in their lens care. Histopathologic examination of these lines revealed trophozoites and cysts. In one of the patients following penetrating keratoplasty, Acanthamoeba castellani and Acanthamoeba polyphaga were cultured by impression cytology of an epithelial line, as well as from the bulbar and tarsal conjunctiva. In the other patient who did not undergo penetrating keratoplasty, these lines appeared in the cornea one month after initial symptoms.

Oculocardiac reflex during manipulation of adjustable sutures after strabismus surgery.

We studied 44 patients who underwent strabismus surgery with the use of adjustable sutures to determine the occurrence of the oculocardiac reflex during the postoperative adjustment process. We defined the reflex as at least a 10% decrease in the baseline heart rate. Only two patients (4.5%) displayed an oculocardiac reflex during the adjustment. We did not identify any preadjustment factors that would increase the susceptibility to develop the reflex.