Jorge N. Buxton

The FDA Report on Intraocular Lenses

Clinical studies of intraocular lenses (IOLs) as investigational devices have been regulated in the United States by the Food and Drug Administration (FDA) since 9 February 1978. As of August 1982, data have been collected on more than one million IOLs implanted. During the last 12 months of the study, 409 000 IOLs were implanted. Visual acuity of 20/40 or better at one year after surgery was present in 85% of over 45 000 cases reviewed. Increasing patient age, surgical problems, postoperative complications, and adverse reactions were factors that reduced the visual acuity. The current trend in the USA is for implantation of posterior chamber and anterior chamber IOLs.

Round and Oval Cones in Keratoconus

In advanced keratoconus, there are two cone types. The more common round or nipple shaped cone is limited in diameter but may reach any degree of conicity. The cone center lies mostly in the lower nasal quadrant. The oval or sagging cone, is often larger and lies more commonly in the inferotemporal quadrant close to the periphery. The oval cone is usually associated with more episodes of corneal hydrops, scarring and difficulty in fitting contact lenses. Histopathologic review of 23 cases (10 round, 13 oval), revealed that the oval group had more breaks in Bowmans membrane, 10.1 versus 5.0, (P smaller than 0.01), and a tendency toward greater pannus formation with more ruptures in Descemets membrane. We hope this clinicopathologic correlation may allow a more logical approach to patient care based on recognizing two different cone types in advanced keratoconus.

Interim FDA Report on Intraocular Lenses

Intraocular lenses have been regulated by the Food and Drug Administration since February 9, 1978. Data reported through August 9, 1979 reveal 177,503 lenses of four different classes have been implanted. The anterior chamber intraocular lens appears to have a higher incidence of certain postoperative complications compared with both control operations and implantation of lenses in the other three classes. The anterior chamber intraocular lens appears to be associated with a lower level of visual acuity compared with both control cases and the other three lens classes during the first six months following implantation. Some complications occurred less frequently following implantation of intraocular lenses than in control cases.

Reconstruction of Filtering Blebs with Free Conjunctival Autografts

BACKGROUND Situations arise in which the surgical repair or revision of filtering blebs is either technically impossible or inadequate, and total reconstruction becomes necessary. This is most frequently encountered in eyes that have undergone multiple procedures, resulting in significant bulbar conjunctival scarring and episcleral fibrosis. METHODS To preserve the pre-existing filtration site, the authors successfully treated five such patients in whom conjunctival scarring adjacent to and surrounding the blebs precluded local revision, by transplanting free conjunctival autografts. Two patients required grafting from the fellow eye. Specific modifications from previously reported conjunctival flap techniques were used to enhance graft healing and continued filtration. RESULTS Satisfactory intraocular pressure control was maintained in all patients receiving minimal to no anti-glaucomatous medications with an average follow-up of 42.6 months (range, 7-90 months). No patient had a significant decrease in visual acuity or surgical complications. CONCLUSION Free conjunctival autografting techniques are a useful adjunct in the surgical revision of leaking, failed, or migrating filtration blebs.

Graft Reactions After Unilateral and Bilateral Keratoplasty for Keratoconus

Penetrating keratoplasty was performed on 134 eyes with keratoconus (102 patients) Including 32 bilateral cases. The incidence of homograft rejection in the first eye of bilateral cases before surgery was performed on the second eve was identical to the incidence in unilateral cases (16%). The incidence of graft rejection was somewhat higher (25%) in the second eye of bilateral surgery, but this difference in rates of rejection was not statistically significant. Surgery on the second eye affected adversely the successful graft on the first even in only one case and this was resolved with medical therapy.

Results of penetrating keratoplasty in the iridocorneal endothelial syndrome.

Five patients (four men and one woman ranging in age from 30 to 41 years) with the iridocorneal endothelial syndrome (four with Chandlers syndrome and one with essential iris atrophy) underwent penetrating keratoplasty for complaints relating to diminished visual acuity or pain. After follow-up periods ranging from one year to four years and seven months (average, 2.7 years), postoperative visual acuities ranged from 20/15 to 20/30. No evidence of recurrence of the corneal abnormalities observed before grafting was apparent in the donor corneas at the last examinations. Two patients who required medical treatment for intraocular pressure control preoperatively also required adjuvant therapy postoperatively. These results suggested that penetrating keratoplasty is a relatively safe and effective procedure for patients with diminished vision or other complaints related to corneal abnormalities in the iridocorneal endothelial syndrome. It does not, however, restore to normal the iris and angle structures affected adversely by the progression of the corneal endotheliopathy and therefore other measures may be required to control intraocular pressure.