Effect of hinged lamellar keratotomy on postkeratoplasty eyes.

PURPOSE: To evaluate the effect of a hinged lamellar keratotomy on refraction, vision, and corneal topography of postkeratoplasty eyes with high-degree astigmatism. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: A hinged lamellar keratotomy was performed on nine eyes of nine patients at least 9 months after penetrating keratoplasty and with high-degree astigmatism. All patients were spectacle and contact lens intolerant. INTERVENTION: A superiorly hinged lamellar keratotomy (corneal flap), 160 microm in thickness and 9 mm in diameter, was created on all eyes included in this study. Each patient was examined 1 day, 1 month, and 3 months after surgery. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best spectacle-corrected visual acuity, refraction, computerized analysis of corneal topography. RESULTS: At each postoperative examination time, there was a significant reduction in both average spherical equivalent (P < 0.05) and average absolute value of astigmatism (P < 0.01) over mean preoperative values. The major changes were seen as early as 1 day after surgery, but both progression and regression of the effect were documented at later postoperative examinations. In all patients best spectacle-corrected acuity was maintained or improved after the procedure. Postoperatively, four patients could be successfully corrected either with spectacles (n = 2) or with gas-permeable contact lenses (n = 2). There were no surgical flap or corneal graft complications. CONCLUSIONS: Hinged lamellar keratotomy improves vision and refraction of postkeratoplasty eyes with high-degree astigmatism. In some cases it may be so effective as to make planned excimer laser treatment unnecessary.

Endokeratoplasty as an alternative to penetrating keratoplasty for the surgical treatment of diseased endothelium: initial results.

PURPOSE: To test the feasibility of a new surgical technique aimed at replacing diseased corneal endothelium while minimizing visual recovery time. DESIGN: Noncomparative, prospective, clinic-based, interventional case series. PARTICIPANTS: A total of seven patients with aphakic bullous keratopathy (n = 2), pseudophakic bullous keratopathy (n = 4), or Fuchs' corneal dystrophy (n = 1) participated. INTERVENTION: All patients underwent a surgical procedure including removal of the epithelium, creation of a 9.5-mm corneal flap, substitution of an underlying 6.5-mm button of deep stroma and endothelium with a 7.0-mm donor button, and suturing of the flap back into position using a 10-0 running nylon suture. In the two most recently operated patients, anterior lamella, 160 microm in thickness, was removed from the donor button before transplantation. MAIN OUTCOME MEASURES: Visual acuity, refraction, keratometry, corneal topography. RESULTS: All corneas were clear, and the surface reepithelialized within 4 weeks after surgery. Regular astigmatism of less than 4 diopters was recorded in all cases as early as 4 weeks after surgery. Epithelial interface ingrowth with extensive melting of the corneal flap was observed in one patient 3 months after surgery and was managed by removal of the flap and resuturing of the donor button. CONCLUSIONS: Endokeratoplasty represents a promising alternative to conventional penetrating keratoplasty for patients with diseased corneal endothelium.

Clinical uses of corneal topography analysis.

Corneal topography analysis has become an indispensable tool in the evaluation and treatment of corneal disease. It is helping us understand the normal corneal shape and how it is altered in ectatic diseases, by contact lens wear, and by surgery. Topography analysis is also now being used in planning procedures to correct astigmatism and in the fitting of contact lenses.

Corneal topography using rasterstereography.

Rasterstereography is a new method of determining the topography of the cornea. Unlike Placido disc types of systems it does not depend on the reflectivity of the corneal surface, and it can provide information about the entire corneal, limbal and interpalpebral conjunctival surfaces. Since a smooth reflective surface is not required, images can be obtained with epithelial irregularity or defects, sutures, or stromal ulceration. A grid of horizontal and vertical bars of light is projected onto the cornea, and the pattern of the grid on the ocular surface is determined by its topography. The image is obtained by a video camera, and digitized, stored, and analyzed by an image processor. A three dimensional image of the corneal surface, contour maps of corneal elevation, and corneal curvature can be displayed.

Unique parameters in the healing of linear partial thickness penetrating corneal incisions in rabbit: immunohistochemical evaluation.

The healing of penetrating nonperforating linear corneal incisions in rabbit was analysed immunohistochemically. Regeneration of the basement membrane (BM) zone was evaluated by analysing the following components using monoclonal antibodies (MAbs): 1) an antigen designated AgHEBM1 (a 66k Mr polypeptide), 2) type VII collagen which is associated with anchoring fibrils and 3) an antigen designated Ag63/D7 which is associated with the lamina densa and anchoring plaques. Concomitant activity in the regenerating stroma was evaluated by analysing the distribution of 1) fibronectin, 2) keratan sulfate and 3) a fetal antigen, designated AgM12, (an intermediate filament associated protein with a Mr of 130k). Synthesis of the BM zone components was not evident at day 2 postwounding but was seen at day 7, only at the deepest aspects of the wounds. Re-establishment of a continuous BM zone was evident by day 60. The stromal regeneration had started by day 7, at the deepest aspect of the wounds, as judged from the distribution of stromal antigens including the fetal antigen AgM12. The number of activated cells (cells expressing AgM12) had decreased significantly by day 30 and diminished by day 60. Between day 30 and day 180 the thickness of the regenerated tissues had not increased significantly although the stroma had not yet reached its normal thickness. Even after six months, the epithelial plug persisted and the concentration of the sulfated epitopes of keratan sulfates in the regenerated stromal matrix were less than in the surrounding nonwounded regions. The cessation of expression of AgM12, by the cells in regenerating stroma, coincided with the relative decrease in extracellular matrix syntheses. The return of the stromal cells to the quiescent state also coincided with re-establishment of a continuous BM zone between the epithelium and the stroma in the regenerated tissue. These observations suggested that the synthesis, assembly and remodeling of stromal and epithelial extracellular matrices during the healing of penetrating corneal wounds may be influenced by the interactions between activated stromal cells and epithelial cells.

Attachment of cultured corneal epithelial sheets to epikeratophakia lenticules.

Tissue lenses for epikeratophakia are currently prepared by one of three different methods: cryolathing and storage in corneal preservation media; cryolathing and lyophilization; or non-freeze microkeratome cutting. It has been proposed that avoidance of the damage caused by freezing or lyophilization will speed healing and recovery of vision. We examined the ability of epithelium to attach to lenses produced in each of the three ways. Human donor corneal epithelium was cultured, and multiple continuous sheets were obtained from each donor eye. Eighteen lenses were prepared by one of the three methods above, and a cultured epithelial sheet was placed on each lens. The percentage of the surface area covered with epithelium and the number of cell layers were determined 24 or 72 hours later. An average of 92% of the lens surface was epithelialized at 24 hours, and 89% was epithelialized at 72 hours. The average number of cell layers was 1.6 at 24 hours and 2.5 at 72 hours, a significant difference. The cryolathed, non-lyophilized lenses showed the lowest percentage of surface area covered, and this was statistically significant at 72 hours.

Results of a graded relaxing incision technique for post keratoplasty astigmatism.

A technique of graded relaxing incisions and compression sutures was performed for correction of post keratoplasty astigmatism in six patients who were spectacle and contact lens intolerant. Correction was achieved in all six patients after surgery, five with spectacles and one with a contact lens. Keratometric astigmatism decreased from an average of 9.63 diopters preoperatively to 2.17 D postoperatively, a reduction of 7.46 D, or 77%. Up to 13.50 D of correction was obtained. In general, the effect of surgery progressed from 1 week to 3 months postoperatively, and regressed from 3 to 6 months. Complications included perforation in two patients, one requiring suturing and application of tissue adhesive, and graft reaction in two patients. Although the number of patients is small, it appears that this technique can successfully reduce post keratoplasty astigmatism, even in excess of 10 D.

Corneal topography using computer analyzed rasterstereographic images.

This paper describes a new method for determining corneal surface detail utilizing a modified Zeiss photo slit lamp. This system projects a grid onto the cornea through a cobalt blue filter. The tear film is stained with fluorescein, causing the projected grid pattern to be visible on the corneal surface. A video image of the grid is then digitized by an image processor which calculates surface detail by evaluating the distortion of the grid lines. Information on curvature and surface detail is obtained across the full corneal surface, both the central optical axis and peripherally beyond the limbus.

Prediction of aphakic refractive error in children.

Formulas created to predict the optical requirements of the aphakic eye have been tested mainly in adult eyes. The accuracy of these formulas in shorter pediatric aphakic eyes was examined using retrospective analysis of 17 aphakic pediatric patients. The Sanders-Retzlaff-Kraff contact lens formula, used previously to predict required lens powers for epikeratophakia, consistently underestimated the required aphakic correction in the shorter eyes, which may have been responsible in part for the large undercorrections obtained previously in patients under one year of age. The Hoffer-Colenbrander and Binkhorst theoretical formulas, Donzis-Kastl-Gordon percentage change formula, and a linear regression formula derived from the present data (LIN), were significantly more accurate. The differences between these formulas were not significant. The use of one of these formulas should facilitate prediction of required epikeratophakia lenticule power or intraocular lens power in young children.

Intraocular lens removal during penetrating keratoplasty for pseudophakic bullous keratopathy.

Pseudophakic bullous keratopathy is now the most common reason for penetrating keratoplasty. In previous reports, the type of intraocular lens (IOL) most frequently encountered in these eyes was the iris plane IOL. The authors reviewed 27 cases of IOL removal during penetrating keratoplasty. Lenses were removed if they were dislocated or associated with iritis, recurrent hyphema, glaucoma, or persistent cystoid macular edema. The IOL encountered most often was the anterior chamber lens (in 22 eyes); closed thin loop, semiflexible or flexible anterior chamber lenses accounted for 19 of these. Iris plane lenses were removed from five eyes. No posterior chamber lenses were removed. Clear grafts were obtained in 24 of 27 cases (89%); visual acuity improved or remained the same in 24 cases, to 20/60 in 11 cases. The most common causes of poor postoperative vision were retinal disease (6/27 cases) and glaucoma (6/27 cases). The association between anterior chamber lenses and pseudophakic bullous keratopathy is probably the result of both the increase in use of these lenses and the documented propensity of the closed loop semiflexible anterior chamber lenses to cause complications.

Combined penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens implantation.

We reviewed 22 cases of triple procedure in the last two years at our institution. Six months postoperatively 21 of the 22 transplanted corneas were clear. One graft for herpetic corneal scarring failed. Best corrected visual acuity was 20/40 or better in 14 patients. The average refractive error was--1.31 +/- 2.30 diopters. Refractive astigmatism was 4 diopters or less in 80% of patients. These results, which compare favorably with previous series, indicate the efficacy and safety of this procedure.

Lectins for the identification of ocular bacterial pathogens.

In a preliminary in vitro investigation, fluorescein-conjugated lectins were used in the identification of bacteria commonly involved in ocular infections. Clinical isolates of Staphylococcus aureus, Staph. epidermidis, Streptococcus pneumoniae, Strep. pyogenes, Pseudomonas aeruginosa, Hemophilus influenzae, and Proteus mirabilis were incubated with each of eleven lectins using a slide technique. Bacterial fluorescence was readily observed with a fluorescence microscope. All clinical isolates bound wheat germ agglutinin. The Gram-positive isolates bound Concanavalin A, while the Gram-negative isolates did not, with rare exceptions. Streptococcal species isolates reacted with Dolichos biflorus agglutinin, while staphylococcal species isolates did not. Lectins may be useful in furthering the initial identification of causative organisms in bacterial ocular infections.

Epikeratophakia with commercially prepared tissue for the correction of aphakia in adults.

The records of all adult patients at Louisiana State University Eye Center, New Orleans, who underwent epikeratophakia for aphakia with commercially prepared tissue since February 1984 were reviewed. The epikeratophakia lenticule was maintained in 37 (92.5%) of 40 patients; complications required the removal of three tissue lenses. The average refractive error three months after surgery was +0.67 +/- 1.97 diopters; 25 (90%) of 28 patients were within 3 D of emmetropia. At six months, the average refractive error was -0.18 +/- 2.27 D. Fourteen (58%) of 24 patients whose visual acuity was 20/40 or better with spectacles before surgery achieved 20/40 spectacle visual acuity three months after surgery, as did ten (59%) of 17 patients at six months and five (83%) of six patients at 12 months. The results in these recent cases are better than in previously reported series and reaffirm the usefulness of epikeratophakia in the treatment of aphakia.

Precarved lyophilized tissue for lamellar keratoplasty in recurrent pterygium.

Thirteen eyes with recurrent pterygia were treated with excision and lamellar keratoplasty using precarved, lyophilized donor cornea. After an average follow-up of 23 months, only one eye (7.7%) required repeat excision. Two eyes (15.4%) had minor recurrences that were asymptomatic and did not progress. Minimal vascularization at the interface between donor and recipient cornea was frequent, but this completely regressed after suture removal and topical corticosteroid treatment. Limitation of movement, when present preoperatively, was improved or eliminated. Best corrected visual acuity was unchanged in eight eyes (61.5%), decreased by one line in two eyes (15.4%), and improved by one or two lines in three eyes (23.1%). Postoperative astigmatism was within 0.5 diopter of the preoperative value in 11 eyes (84.6%); one eye (7.7%) had a postoperative increase of 1 diopter and another eye (7.7%) of 2 diopters.