Penetrating keratoplasty 1981-1988: clinical indications and pathologic findings

Morphometry of Corneal Endothelium in Patients with Corneal Guttata

OBJECTIVE

To study the morphology of the corneal endothelium in patients diagnosed with corneal guttata using an image processing algorithm based on a contour detection method.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Twenty-four subjects with known corneal guttata.

METHODS

Two hundred eight images of corneal endothelium, captured with a noncontact specular microscope were analyzed using the Contour method, which demonstrates endothelial cell density (ECD), coefficient of variation of cell area, percentage of 4- to 8-sided cells as well as the number, area, and coefficient of variation of corneal guttata.

MAIN OUTCOME MEASURES

The number, surface area, and coefficient of variation of corneal guttata.

RESULTS

Corneal position had no significant effect on ECD or on the percentage of endothelial cells with 4, 5, 7, or 8 sides. However, the coefficient of variation of images taken from the central cornea was significantly larger than those taken at the 2- and 6-o'clock positions. In addition, the percentage of hexagonal cells was significantly lower in pictures of the central position compared to those located in the upper paracentral position. The numbers and surface areas of guttata were significantly larger in pictures of the central compared to some paracentral positions. Subjects who had previously undergone cataract surgery with intraocular lens (IOL) implantation did not show different areas of corneal guttata, but exhibited a significantly lower cell density (1825+/-582) compared with unoperated patients (2400+/-457/mm2). Analogously, the only significant change observed in paired comparisons between the operated eye of patients with unilateral cataract extraction with IOL implantation and their unoperated fellow eye was a lower cell density obtained in operated eyes. Compared with normal subjects, subjects with corneal guttata were shown to have a significantly lower ECD, a lower proportion of hexagonal cells, and a higher coefficient of variation of cell area in the central cornea.

CONCLUSION

This study supports the finding that corneal guttata mainly affect the central corneal area. A future prospective study using the described Contour detection method would be helpful to evaluate more accurately the risks associated with the evolution of corneal guttata into Fuchs' dystrophy.

National Survey on Bullous Keratopathy in Japan

PURPOSE

To present the results of a national survey on bullous keratopathy (BK) in Japan.

METHODS

A cross-sectional national survey was conducted for 963 eyes with BK seen between 1999 and 2001 by members of the Japan Cornea Society. Demographic characteristics, type of surgery, complications, and postoperative outcome were analyzed.

RESULTS

BK accounted for 24.2% (963 eyes) of total keratoplasties performed during the period. Graft clarity was maintained in 77.4% of cases, and immunologic rejection and elevated intraocular pressure was noted in 10.8% and 15.3%, respectively. Cataract surgery was the most common cause of BK (n = 428, 44.4%), and phacoemulsification and aspiration were performed in approximately 40% of cases. BK secondary to laser iridotomy (LI) was the second most common cause of BK (n = 225, 23.4%). LI was performed as a prophylactic measure in approximately one half of these cases. BK developed with a mean duration of 6.8 years after LI. Fuchs dystrophy was the cause of BK in 18 eyes (1.9%).

CONCLUSIONS

The causes of BK in Japan are considerably different from those in other Western countries. LI-related BKs showed a remarkably high number, whereas Fuchs dystrophy was observed only rarely.

Risk Factors for the First Episode of Corneal Graft Rejection in Keratoconus

PURPOSE

To evaluate the relationship between topical corticosteroids and other variables and the risk for rejection after penetrating keratoplasty for keratoconus.

METHODS

The records of all keratoconus patients who, after their first penetrating keratoplasty in that eye, experienced a first episode of corneal graft rejection during a specific 3-year period were retrospectively reviewed in a case-control fashion. Twenty-three cases were identified, and they were matched with 3 controls each, for a total of 69 controls and 92 total patients. Multiple variables including steroid potency, recent steroid tapering, and length of time on the current level of steroids were analyzed to see whether there were any significant relationships between postoperative changes in steroid management and rejection. In addition, other variables such as graft size, suture technique, recent suture removal, suture status at the time of the rejection episode, and prior grafting in the fellow eye were examined to determine if any of these factors were associated with a higher risk of graft rejection.

RESULTS

Most of the proposed risk factors, including steroid dose and tapering, differing suturing techniques, loose and/or broken sutures at the time of rejection, percentage of sutures remaining at the time of rejection, and prior grafting in the fellow eye, did not correlate with the risk of rejection. Only graft size had a correlation, with host trephination size > or = 8.25 mm having a nearly sixfold increased risk of rejection (P = 0.015). Most patients (70%) were diagnosed with rejection at a scheduled office visit rather than at an emergency visit, and correspondingly, nearly one half (43%) had no symptoms when rejection was identified. There was no significant difference in final best-corrected visual acuities between the cases and controls, and 91% of the corneas that underwent rejection did not progress to graft failure, remaining centrally clear at most recent follow-up.

CONCLUSION

In this study, the most important risk factor for rejection after corneal transplantation for keratoconus was the size of the graft. Physician detection of rejection is paramount, because a graft rejection episode is more often diagnosed at a scheduled office visit than at an emergency visit. Fortunately, progression to graft failure can usually be prevented if treatment is started promptly and intensively.

Trends in the indications for penetrating keratoplasty, 1980-2001

PURPOSE

To study the leading indications and changing trends for penetrating keratoplasty (PK) over the past 3 decades.

METHODS

This is a retrospective review of 696 cases of PK. The indications for PKs performed at the Duke University Eye Center during the years 1980-1981, 1990- 1991, and 2000-2001 were tabulated to determine trends over the past 3 decades. The main outcome measures were indications for PK.

RESULTS

During this study, 696 PKs were performed. The leading indications for PK and their respective frequencies during 1980-1981, 1990-1991, and 2000-2001 were failed grafts (10.8%, 19.0%, 27.0%, respectively), pseudophakic bullous keratopathy (PBK)/aphakic bullous keratopathy (ABK) (19.4%, 20.6%, 16.7%, respectively), Fuchs dystrophy (15.6%, 13.0%, 23.8%, respectively), keratoconus (13.4%, 8.2%, 11.8%, respectively), and corneal scar (7.0%, 8.9%, 10.7%, respectively). The number of PKs for failed grafts and Fuchs dystrophy increased over time.

CONCLUSIONS

In this study, failed graft has gradually become the leading indication for PK, whereas most other studies have reported PBK as the leading indication. Unlike many other studies, Fuchs dystrophy was a common indication for PK.

Risk factors for progression to penetrating keratoplasty in patients with keratoconus

PURPOSE

To determine clinical and demographic risk factors for corneal transplantation in keratoconus patients.

DESIGN

Case control study.

METHODS

SETTING

Tertiary referral center.

STUDY POPULATION

All keratoconic eyes presenting to the Duke University Eye Center from January 1, 1997, to December 31, 2002. OBSERVATION PROCEDURE AND OUTCOME MEASURES: Cases were defined as eyes undergoing transplantation during the study period for keratoconus. Controls were defined as eyes that did not undergo transplantation. Cases were compared with controls to determine clinical and demographic risk factors for corneal transplantation.

RESULTS

A total of 131 eyes with keratoconus were studied; 59 cases were compared with 72 controls. Groups were similar with respect to sex and race. Significant univariate risk factors for corneal transplantation were best-corrected vision worse than 20/40 (OR 3.2, 95% CI 1.1 to 9.8), cylinder >10.0 diopters (OR 3.5, 95% CI 1.0 to 12.4), and average keratometry >55 diopters (OR 5.6, 95% CI 1.4 to 21.9). In multivariate analysis, age 30 or younger conferred a sevenfold increased risk of transplantation compared with ages of more than 40 (OR 7.7 for ages 21 to 30 and OR 25.8 for ages < or = 20). Multivariate analysis also showed duration of disease 5 years or less and steep average keratometry as significant risk factors.

CONCLUSIONS

A subset of young keratoconic patients with high keratometry values may represent an underrecognized risk group for corneal transplantation. Best-corrected visual acuity worse than 20/40 at presentation and astigmatism are other clinical indicators of increased risk of corneal transplantation in keratoconus patients.

Visual outcome in corneal grafts: a preliminary analysis of the Swedish Corneal Transplant Register

AIM

To assess visual outcome and the incidence of complications at 2 years postoperatively in corneal grafts reported to the Swedish Corneal Transplant Register.

METHODS

Preoperative and 2 year follow up data were submitted to the Swedish Corneal Transplant Register by surgeons in eight corneal transplant clinics in Sweden. Preoperative data on 1957 grafts and 520 grafts with 2 year follow up were included in the analysis. Data were analysed by multiple linear and logistic regression methods, as appropriate.

RESULTS

The major diagnostic categories were keratoconus (29%), bullous keratopathy (21%), and "other diagnosis" (32%). Fuchs' endothelial dystrophy and stromal dystrophies accounted for 15% and 3% of grafts, respectively. At 2 years the overall incidence of complications, other than rejection and regrafting, was 26%, with an increasing frequency from keratoconus < Fuchs' dystrophy < bullous keratopathy < "other diagnosis." Rejection was observed in 15% of grafts and was more likely in the bullous keratopathy (OR 3.1, 95% CI 1.1 to 9.0, p=0.04) and "other diagnosis" (OR 2.6, 95% CI 1.1 to 5.9, p=0.03) groups. Regrafting, which occurred in 10% of cases, was not influenced by diagnosis, but it was related to the incidence of rejection (OR 14.8, 95% CI 6.1 to 35.9, p<0.001) and other complications (OR 4.4, 95% CI 1.9 to 10.4, p=0.001), and to the presence of other sight threatening pathology in the eye (OR 3.6, 95% CI 1.3 to 9.9, p=0.01). Visual acuity was improved in a high proportion of the patients, especially those with keratoconus and Fuchs' dystrophy where, respectively, 86% and 54% of grafts achieved a visual acuity of > or =0.5 at 2 years, compared with only 31% with bullous keratopathy and 35% in the "other diagnosis" group. 60% of grafts for keratoconus and Fuchs' dystrophy achieved a visual acuity equal to or better than the other eye. Postoperative astigmatism was higher in the bullous keratopathy (p=0.01) group. Patients with high astigmatism benefited from refractive surgery, showing a reduction from 7.9 (95%CI 6.9, 8.7) to 3.2 (95% CI 2.6, 3.9) dioptres (p<0.001). A centre effect was evident in visual outcome.

CONCLUSION

The overall incidence of complications was related to diagnosis. Complications other than rejection and regrafting were most likely in the "other diagnosis" group, and further analysis of this group is therefore planned. The best improvement in visual acuity and the lowest astigmatism were achieved in the keratoconus and Fuchs' dystrophy groups; but the influence of diagnosis on astigmatism was small and, overall, the statistical model accounted for only 8% of the variability in astigmatism. Refractive surgery was, however, effective in reducing astigmatism. It is hoped that a better understanding of the factors that determine the visual outcome of grafts will emerge from future analyses of the Swedish Corneal Transplant Register, helping to refine the criteria for patient selection and to guide clinical practice.

Nineteen years of penetrating keratoplasty in the Hotel-Dieu Hospital in Paris

PURPOSE

To identify changing trends in penetrating keratoplasties (PKs) performed at the Hotel-Dieu Hospital in Paris between January 1980 and December 1999 and to explain the reasons for the changes.

METHODS

We retrospectively reviewed 3,736 of the 3,836 PKs performed between January 1, 1980, and December 31, 1999, and classified them into diagnostic categories.

RESULTS

The most common indications for PK were keratoconus (28.8%), herpetic infections (10.9%), graft failures (9.9%), aphakic and pseudophakic corneal edema (9.9%), Fuchs' endothelial dystrophy (9.4%), and nonherpetic leucoma (7.7%). Other indications represented 23.4% of the cases. The incidence of aphakic and pseudophakic corneal edema progressively increased between 1980 and 1991, became the most frequent indication in 1991 (21.4%), and then progressively decreased. The annual number of PKs increased between 1980 and 1986, decreased between 1987 and 1997, and increased again after September 1997. The decrease was caused by both a shortage of corneal buttons, and, in 1987, the fear of transmitting diseases through corneal transplantation, particularly human immunodeficiency virus. Beginning in 1992, decreases were also associated with stringent governmental regulations of eye bank tissue.

CONCLUSION

Changes in the incidence and management of corneal disorders were the primary factors leading to modifications of grafting until 1987. After 1987, corneal button shortage probably corresponded to the acquired immune deficiency syndrome epidemic. Governmental regulations of eye banking led to a severe corneal button shortage between 1992 and 1997. Despite an increase in the number of PKs performed after 1997, corneal buttons are still preferentially allocated to patients in whom there is a high probability of graft success.

Intraocular lens exchange for anterior chamber intraocular lens-induced corneal endothelial damage

BACKGROUND

Anterior chamber and iris-plane intraocular lenses (IOLs) have been implicated in causing corneal endothelial damage and progression to pseudophakic bullous keratopathy.

METHODS

The authors performed IOL exchanges on 102 eyes with signs of early corneal decompensation or progressive endothelial cell loss associated with these anterior chamber or iris-plane IOLs. Replacement IOLs were posterior chamber lenses sutured to the iris (87 eyes), sutured to the sclera (3 eyes), or placed in the ciliary sulcus (12 eyes).

RESULTS

Seventy-two eyes (71%) had the same or improved vision after a mean follow-up period of 18.6 months (range, 6 to 60 months). Only 24 eyes (23.5%) progressed to corneal decompensation. Of the eyes that decompensated, 75% had preoperative endothelial cell counts of 500 cells/mm2 or less (P < 0.0001), and 83% had preoperative signs of early corneal decompensation (P < 0.001). Biomicroscopic signs of early corneal decompensation seen preoperatively in 50 eyes resolved in 17 eyes (34%) and remained unchanged in 12 eyes (24%) at the last postoperative follow-up visit.

CONCLUSION

Removal of anterior chamber and iris-plane intraocular lenses in eyes showing signs of endothelial damage may prevent progression to pseudophakic bullous keratopathy if performed before a critical degree of endothelial cell loss or dysfunction has developed.