Simultaneous penetrating keratoplasty and amniotic membrane transplantation in eyes with a history of limbal stem cell deficiency

PURPOSE

To describe the outcomes of simultaneous penetrating keratoplasty (PK) and amniotic membrane transplantation (AMT) performed both as a ring-shaped graft and as a temporary patch in eyes with a history of limbal stem cell deficiency (LSCD).

METHODS

Prospective observational case series including 48 simultaneous PK/AMT procedures (48 patients) in eyes with a history of partial or total LSCD. Patients with total LSCD were first treated with limbal stem cell transplantation. The preoperative indication was graft failure in 58.3% of cases. Most recipients (89.6%) were at high-risk for rejection.

RESULTS

The mean graft reepithelialization time was 29.2±30.8 days. Graft reepithelialization was achieved in 30 days in 70.8% of cases. No AMT-related adverse events were observed. The mean time from keratoplasty-to-last visit was 84.5±54.5 months. The 3-year graft survival rate was 62.5%. Recurrence of corneal epithelial defects after graft reepithelialization (47.9%) was associated with lower graft survival (P=0.004). In eyes with successful grafts at the last visit, the mean LogMAR visual acuity was 1.90 (20/1575)±5 lines before keratoplasty and 0.89 (20/155)±10 lines at 5 years. A ring of amniotic membrane was visible between the graft stroma and the corneal epithelium on slit-lamp examination and optical coherence tomography in all successful cases.

CONCLUSIONS

In this series of eyes with a history of LSCD and at high-risk of rejection, simultaneous PK and AMT were associated with satisfactory graft survival and no additional adverse events.

[Influence of surgical technique on graft and endothelial survival in endothelial keratoplasty]

PURPOSE

To report survival of the graft and its endothelium after Descemet Stripping Endothelial Keratoplasty (DSEK) in a series of consecutive cases with no exclusion of cases corresponding to the learning curve and to analyze the influence of surgical techniques on survival.

PATIENTS AND METHODS

This prospective observational study includes 170 consecutive DSEK's performed between 2006 and 2013. The main outcome criteria were graft survival and survival of the donor corneal endothelium as assessed by specular microscopy. The following parameters were analyzed: preoperative diagnosis, lens status, surgical techniques, and graft thickness.

RESULTS

Graft survival was 91.7% at 1 year and 71.5% at 3 years. Graft survival was significantly associated with surgical technique (P=0.04). The best graft survival was achieved with scleral incision combined with graft insertion with the Endosaver® device (dedicated DSEK injector). Graft survival decreased with graft thickness (P<0.001). One-year endothelial cell density was significantly associated with surgical technique (P=0.003). Early 1-year endothelial cell loss was 42.0% for the scleral incision/Endosaver® group, 48.7% for the corneal incision/Endosaver® group, 49.4% for the corneal incision/Busin guide group, 66.0% for the corneal incision/IOL injector group, and 66.7% for the scleral incision/forceps group (P=0.002).

CONCLUSION

The success rate of DSEK is close to that of penetrating keratoplasty. The use of a DSEK-dedicated injector results in higher survival of the graft and its endothelium. The use of ultrathin grafts also appears to represent significant progress.

Tissue crossmatch before corneal transplantation

AIM

To investigate the influence of anticorneal antibodies on the outcome of transplantation in recipients before penetrating keratoplasty.

METHODS

100 consecutive penetrating keratoplasties performed between July 1995 and June 1996 were included in this study. Donor corneoscleral rim cryosections were incubated with recipient serum. Fixation of recipient IgM on donor corneas was revealed with a polyclonal anti-human mu-chain antibody. The mean follow up time was 61 months. Five years after transplantation, 63% of patients were available for follow up. During the follow up period, 15% of keratoplasties failed because of irreversible rejection.

RESULTS

Anti-donor stromal lamellae IgM were found in 14 recipients. Anti-donor keratocyte IgM were present in 28 recipients. Dilution of recipient serum (up to 1/800) did not modify the results of positive crossmatch assays. Crossmatch assays performed with positive recipient sera and negative donor corneoscleral rims were negative. No significant influence of IgM crossmatch results on graft survival and rejection-free graft survival was found.

CONCLUSION

Donor specific anticorneal stroma IgM were found in 28% of recipients before transplantation. This pre-immunisation was not associated with a higher risk of transplantation rejection.

Outcome of Corneal transplantation rejection

PURPOSE

To identify predictive factors for reversibility of corneal graft rejection.

METHODS

The study design was a prospective cohort study. Among 440 consecutive penetrating keratoplasties performed at our institution, 79 grafts from 79 patients who developed signs of transplant rejection were included. Donor, recipient, surgical, and rejection variables were studied, at both univariate and multivariate levels.

RESULTS

The rate of reversibility was 51% (40/79). The average postoperative time of rejection was 10.5 +/- 9.3 months, and the average time of visual acuity recovery in patients with reversible rejection was 2.4 +/- 2.3 months. In logistic regression, only two variables significantly influenced the rate of reversibility. The preoperative diagnosis (p = 0.04) influenced the rate of rejection reversibility; patients with bullous keratopathy or regraft were more likely to experience irreversible rejection than patients with keratoconus or Fuchs' dystrophy. The average graft thickness at the time of rejection diagnosis was 774 +/- 129 microm in patients with irreversible rejection and 681 +/- 118 microm in patients with reversible rejection (p = 0.001).

CONCLUSION

Rejection was reversible in half of the cases. Rejection was more likely to be irreversible in patients with marked increase in graft thickness and in patients transplanted for bullous keratopathy or graft failure. Donor variables did not influence rejection reversibility.

Screening human donor corneas during organ culture for the presence of guttae

AIMS

To detect the presence of guttae by means of light microscopy during organ culture and to evaluate the influence of the presence of guttae in the donor tissue on transplantation outcome.

METHODS

Donor corneas were investigated for the presence of guttae by means of light microscopy at the end of organ culture. Recipient corneal buttons from patients with severe Fuchs' dystrophy and donor corneas with advanced guttae were first studied by light microscopy and subsequently by transmission electron microscopy. Lastly, 168 consecutive donor corneas were evaluated for the presence of guttae and issued for transplantation.

RESULTS

Corneal specimens with Fuchs' dystrophy displayed numerous round highly reflecting guttae at the level of the corneal endothelium. Donor corneas with advanced guttae showed less numerous guttae. Among 168 organ cultured donor corneas issued for transplantation, low density guttae were found in 43 (25.6%) corneas. The endothelial cell density and figure coefficient were significantly lower and organ culture time was significantly higher in the cornea guttata group than in the control group. The presence of grouped guttae significantly decreased the adjusted graft survival. The incidence of postoperative stage 3 cornea guttata was significantly higher when grouped guttae were found (5/6) than when no guttae or scattered guttae were found (8/101).

CONCLUSION

Cornea guttata can be detected during organ culture by means of light microscopy. It is associated with a decrease in endothelial cell figure coefficient and cell density. The presence of grouped guttae is associated with poorer graft survival and more frequent stage 3 cornea guttata in the graft after transplantation.

Corneal endothelial cell apoptosis in patients with Fuchs' dystrophy

PURPOSE

To investigate whether apoptosis plays a notable role in degeneration of corneal endothelial cells in patients with Fuchs' dystrophy.

METHODS

Forty-seven corneal buttons from 41 patients with Fuchs' dystrophy were studied. Nucleus labeling, transmission electron microscopy (TEM), and TdT-dUTP terminal nick-end labeling (TUNEL) were used to detect apoptosis. TEM and TUNEL were performed on sections of all 47 corneal buttons, and nucleus labeling was performed on the last 10 corneas. Seven human donor corneas, two corneal buttons from two patients with keratoconus, and one corneal button from a patient with interstitial keratitis were used as negative controls for detection of apoptotic endothelial cells. Negative controls were studied by means of nucleus labeling, TUNEL, and TEM.

RESULTS

In the nucleus labeling assay, the average percentage of apoptotic endothelial cells was 2.65% in the Fuchs' dystrophy group (n = 10) and 0.23% in the control group (n = 10; P = 0.0003). In the TUNEL assay, labeling of some endothelial cells was observed on 42 of 47 corneas in the Fuchs' dystrophy group, whereas it was absent on most specimens of the control group. In TEM, most endothelial cell nuclei had a normal appearance, and apoptotic endothelial cells featuring condensed nucleus and decreased cell size could be observed exceptionally. Some apoptotic cells were found in the basal epithelial cell layer by means of nucleus labeling, TUNEL, and TEM in the Fuchs' dystrophy group but not in the control group.

CONCLUSIONS

This study suggests that apoptosis plays an important role in endothelial cell degeneration in Fuchs' dystrophy. Because of a lack of conclusive evidence of increased endothelial apoptosis by TEM, further studies are needed to ascertain this finding.

Automated keratoconus detection using the EyeSys videokeratoscope

PURPOSE

To evaluate the effectiveness of indices derived from the EyeSys System 2000 in detecting keratoconic corneas.

SETTING

Department of Ophthalmology, Hôpital Saint Antoine, Paris VI University, Paris, France.

METHODS

Topographies of 208 corneas were evaluated. The corneas were from 8 groups of patients classified by the following diagnoses: normal, regular astigmatism, cataract, radial keratotomy, photorefractive keratectomy, myopic keratomileusis, penetrating keratoplasty (PKP), and keratoconus. Nine statistical indices derived from EyeSys data, 2 Holladay Diagnosis Summary indices (coefficient of uniformity and coefficient of asphericity [Asph]), and our refractive power symmetry index were studied. A training set of 104 corneas was used to determine the most efficient threshold value of each index based on sensitivity and specificity curves. Decision trees combining 2 indices were generated. Sensitivity and specificity were calculated in a validation set composed of the remaining 104 corneas.

RESULTS

Based on the results of the training set, the optimum indices were SDSD (standard deviation of the standard deviations of the radii of curvature of each ring) and Asph. In the validation set, the decision tree using these indices featured 88.5% sensitivity and 94.9% specificity; the 4 false-positive cases were in corneas in the PKP group of patients.

CONCLUSIONS

Clinically apparent keratoconus can be detected among normal corneas and irregular corneal shape patterns using the EyeSys System 2000 data and a decision tree combining 2 indices.

Effects of penetrating keratoplasty suture removal on corneal topography and refraction

PURPOSE

To study the refractive and topographic modifications induced by penetrating keratoplasty suture removal.

METHODS

We retrospectively studied 50 corneas from 50 patients who had undergone penetrating keratoplasty. All of the eyes were examined before and after all sutures were removed at 10.8+/-4.7 months and 20.3+/-7.9 months after keratoplasty. Subjective refraction, best spectacle-corrected visual acuity (LogMAR units), and corneal topography (EyeSys 2000R device) were recorded.

RESULTS

Suture removal decreased the subjective cylinder by an average of 0.91+/-2.32 D (p = 0.004) and modified the corneal topographic pattern (p = 0.03) and shape (p < 0.001) distribution. The change in subjective cylinder correlated with the variation of the steepest meridian power (r(s) = 0.46; p < 0.001). It correlated with the change in topographic pattern (r(s) = 0.59; p < 0.001). The subjective spherical equivalent increased (hyperopization) by an average of 0.61+/-2.24 D (p = 0.01). After suture removal, the prolate shape was less frequent, and the oblate shape was more frequent than before suture removal. Best spectacle-corrected visual acuity increased by an average of 0.8+/-2.0 lines (p = 0.004). The change in subjective cylinder correlated with the change in visual acuity (r(s) = 0.36; p = 0.006).

CONCLUSION

Suture removal modifies the corneal topographic pattern and shape. It decreases the subjective cylinder and induces an hyperopization. Visual-acuity improvement after suture removal mainly is explained by the decrease in astigmatism. Suture removal seems particularly helpful in corneas with a bow-tie pattern.

Influence of fetal calf serum, fibroblast growth factors, and hepatocyte growth factor on three-dimensional cultures of human keratocytes in collagen gel matrix

BACKGROUND

We set out to evaluate the influence of fetal calf serum, acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF) on three- dimensional cultures of human keratocytes in type I collagen gel matrix.

METHODS

Polymerized gels were cultured at 37 degrees C for 35 days. Gel contraction and integrated optical density were assessed 3 times weekly for 5 weeks using an image analysis system. Gels were studied at the end of the culture period by means of transmission electron microscopy (TEM) and immunochemistry.

RESULTS

Serum significantly increased gel contraction and decreased gel optical transmittance. Keratocyte density was significantly increased by serum and HGF. In TEM, collagen density was higher with serum-supplemented media than with serum-free media, and higher with HGF-supplemented media than with HGF-free media. Immunoperoxidase staining of keratocyte-populated gels showed positive staining for vimentin, connexin 43, and type I, type V, and type VI human collagen, whereas no expression of desmin, alpha smooth muscle actin, and type IV collagen was observed. Expression of type I collagen was significantly increased by aFGF and HGF, expression of type VI collagen by serum and bFGF.

CONCLUSION

Serum and HGF improve ultrastructural and immunochemical features of human keratocyte-populated collagen gels.

Ultrastructure of cultured and cryopreserved human corneal keratocytes

PURPOSE

To describe the ultrastructural features of cultured and cryopreserved keratocytes.

METHODS

Isolated human keratocytes were cultured with 10% fetal calf serum and 10 ng/ml acidic fibroblast growth factor. The 10% Me2SO and 10% human albumin were used as cryoprotective agents. Cells were cooled at 2 degrees C/min, then thawed at 37 degrees C, and subsequently recultured. They were studied by means of transmission electron microscopy (TEM).

RESULTS

TEM of cultured keratocytes before cryopreservation showed a network of intact connecting cells. The average cell thickness was 2.4 microm in cross sections and 5.8 microm in frontal sections. The average nuclear thickness was 1.6 microm in cross sections and 3.7 microm in frontal sections. Nuclei appeared regular and oval in cross sections and indented in frontal sections. Organelles were found in greater amounts in frontal sections than in cross sections. Gap junctions, fenestrations along the cell surface, omega-shaped structures, fibrils, and filamentous networks also were found. Most of the just-thawed, suspended cells were elongated and condensed but had intact plasma membranes. These cells were surrounded by a granular material, corresponding to the albumin-containing thawing medium. Scattered isolated round cells displayed nuclear damage, cell edema, loss of organelles, and cell-membrane disruption. By the end of reculture after cryopreservation, cultured keratocytes displayed the same ultrastructural features as before cryopreservation.

CONCLUSION

Cultured human keratocytes display many ultrastructural features of in situ keratocytes. These features are still present after reculture after cryopreservation. Cryopreservation induces necrosis in a small percentage of cells, which seems to be related to a relative lack of cell-membrane protection by the cryoprotectants used.

Prediction of spectacle-corrected visual acuity using videokeratography

PURPOSE

Our aim was to improve prediction of spectacle-corrected visual acuity (SCVA) using indices derived from the EyeSys System 2000 data (version 3.1).

METHODS

We studied corneal topography in 182 eyes from 8 groups of patients. Holladay Diagnostic Summary indices were recorded. Nine statistical indices calculated with the first 8-ring data and refractive power symmetry index were also studied. Correlation with SCVA (LogMAR units) was studied by means of Pearson's regression. Multiple linear regression was used to obtain linear equations combining several indices.

RESULTS

At a univariate level, total astigmatism cylinder showed the strongest correlation with SCVA (r = .63, P = .0001). At a multivariate level, the predicted visual acuity obtained by linear equation combining the asphericity coefficient, the predicted corneal acuity, the mean of the means, and the total astigmatism cylinder was closely associated with SCVA (r = .72, P = .0001). It was identical to SCVA in 58.2% of the cases, within one line in 75.8%, and within two lines in 91.2%.

CONCLUSION

Multiple linear regression resulted in the best prediction of spectacle-corrected visual acuity, giving notable improvement in prediction of spectacle-corrected visual acuity as compared to the predicted corneal acuity available in the EyeSys System 2000.

The results of successful penetrating keratoplasty using donor organ-cultured corneal tissue

BACKGROUND

The aim of this study was identification of predictive factors for postoperative visual acuity in patients with a clear organ-cultured graft and to analyze the change in visual acuity between 12 and 24 months after transplantation.

METHODS

The study design was a prospective cohort study. A total of 342 consecutive penetrating keratoplasties using donor organ-cultured grafts, performed in 324 patients, were included. Visual acuity, graft thickness, and graft endothelial cell density were recorded in patients with clear transplants.

RESULTS

At 24 months postoperatively, 25 (18.7%) of 134 patients had 20/200 or worse visual acuity and 66 (49.3%) had 20/40 or better visual acuity. Graft thickness took 1 month to decrease to normal values. A temporary graft thinning occurred at 6 months postoperatively, followed by recovery of normal graft thickness by 18 months. The average postoperative endothelial cell density was 1,533+/-598 cells/mm2 during the second year. The 24-month LogMAR (logarithm of minimal angle of resolution) visual acuity correlated with preoperative LogMAR visual acuity (beta=0.26, P=0.005), postoperative lens status (beta=-0.34, P=0.008), preoperative intraocular pressure (beta=0.50, P=0.020), and postoperative astigmatism (beta=0.17, P=0.040). Visual acuity (P=0.022) significantly improved between 12 and 24 months. Preoperative diagnosis (P < 0.0001) and postoperative lens status (P < 0.0001) significantly influenced the change in LogMAR visual acuity between 12 and 24 months.

CONCLUSIONS

Donor variables do not influence the visual acuity results of penetrating keratoplasty using organ-cultured donor tissue, whereas they have a strong influence on graft survival and graft endothelial cell density. Visual acuity improves during the first 2 years after transplantation. After keratoplasty, organ-cultured corneal grafts undergo dramatic modifications of their thickness and probably of their transparency.

The triple procedure: in the bag placement versus ciliary sulcus placement of the intraocular lens

AIMS

To evaluate the influence of intraocular lens (IOL) placement on triple procedure clinical results and to investigate whether it is appropriate to use phacoemulsification in patients with large lens nucleus.

METHODS

40 consecutive penetrating keratoplasties combined with cataract extraction performed in a single institution were studied. Whenever possible a capsulorhexis was performed and the IOL was placed into the capsular bag. Phacoemulsification was used when the nucleus was too large to pass through the capsulorhexis.

RESULTS

Out of 25 patients with an intact capsulorhexis phacoemulsification was used in 13 (52.0%) whereas the entire nucleus passed through the capsulorhexis in the remaining 12 patients (48%). The average 12 month visual acuity was 0.46 (SD 0.21) in patients with in the bag IOL (n = 23) and 0.29 (0.08) in patients with ciliary sulcus IOL (n = 13) (p = 0.04). Elevated intraocular pressure occurred in 26.1% (6/23) of patients with in the bag IOL and 61.5% (8/13) of patients with ciliary sulcus IOL (p = 0.08). The average postoperative graft thickness at 18 months was 552 (27) microns in the former group and 650 (29) microns in the latter group (p = 0.04). No significant difference in graft survival, postoperative endothelial cell density, astigmatism, and videokeratoscopic measurements was found between both groups.

CONCLUSION

In the bag placement of the intraocular lens during the triple procedure results in better outcome of transplantation than ciliary sulcus placement of the IOL. Phacoemulsification allows removal of large nuclei through a 5 mm capsulorhexis without performing relaxing incisions out towards the periphery of the capsule.

Surgical correction of postkeratoplasty astigmatism with the Hanna arcitome

PURPOSE

To report the results of arcuate keratotomy performed with the Hanna arcitome in patients with postkeratoplasty astigmatism.

SETTING

Department of Ophthalmology, Saint-Antoine Hospital, Paris VI University, Paris, France.

METHODS

This retrospective study comprised 22 eyes (22 patients) with postkeratoplasty astigmatism. Paired symmetrical arcuate keratotomy was performed with the Hanna arcitome. Outcome measures included refraction, videokeratography, and keratometry.

RESULTS

At 6.6 months +/- 8.9 (SD) after surgery, the mean increase in best spectacle-corrected visual acuity (BSCVA) was 2.1 +/- 2.4 lines. Thirteen eyes gained 2 lines or more of BSCVA, and 15 gained 3 lines or more of uncorrected visual acuity. Two patients had a decrease in BSCVA: 1 had lens opacification unrelated to arcuate keratotomy and 1, increased corneal irregularity. Mean refractive astigmatism was 6.94 +/- 2.11 diopters (D) preoperatively and 3.85 +/- 1.95 D postoperatively (P < .01). Mean change in keratometric astigmatism was -51 +/- 36%. Astigmatism decreased in 21 eyes as measured by manifest refraction, keratometry, and videokeratography; it increased in 1 cornea with a microperforation.

CONCLUSIONS

The results of arcuate keratotomy performed with the Hanna arcitome were comparable to those with freehand relaxing incisions. The instrument made safer and more uniform arcuate incisions than a freehand technique.

Videokeratography, keratometry, and refraction after penetrating keratoplasty

PURPOSE

To identify the correlation between videokeratography, autorefractometry, autokeratometry, and keratometry measurements and the subjective manifest refraction and spectacle-corrected visual acuity after penetrating keratoplasty.

METHODS

We studied 100 eyes from 100 patients that had undergone penetrating keratoplasty. All eyes were examined by videokeratography (EyeSys 2000) (axial, tangential, and refractive power maps), autorefractometry, autokeratometry, and keratometry. Measurements were made at an an average of 19 +/- 9 months after surgery. Postoperative refractive astigmatism, spherical equivalent refraction, and spectacle-corrected visual acuity were studied by regression analysis.

RESULTS

Both the total topographic cylinder measured by the refractive power map and topographic cylinder measured by the axial power map showed the strongest correlation with the manifest refractive cylinder (rs = +0.89, P < .001). The axis of astigmatism determined by keratometry and autokeratometry showed the strongest correlation with the subjective manifest refraction axis (rs = +0.87, P < .001). The total topographic cylinder showed the strongest correlation with the spectacle-corrected visual acuity (rs = +0.38, P = .001); however the topographic indices of predicted corneal acuity, corneal acuity, corneal uniformity index, asphericity, and refractive power symmetry did not correlate with spectacle-corrected visual acuity.

CONCLUSION

Measurement of astigmatism after penetrating keratoplasty can be made more accurate by using videokeratographic measurements to supplement retinoscopic and manifest refraction. Other useful methods for predicting the axis of refractive astigmatism include keratometry, autokeratometry, and autorefractometry. In this study, indices designed to measure corneal surface irregularity failed to predict visual acuity after penetrating keratoplasty.

Microbiologic study of organ-cultured donor corneas

BACKGROUND

Our purpose was to evaluate the sterility of organ-cultured human donor corneas at the time of surgery.

METHODS

We studied 603 organ-cultured corneas. Of these 603 corneas, 409 (68%) were grafted and 69 (11%) were contaminated during storage.

RESULTS

Contamination during preservation was either bacterial (65%) or fungal (35%). None of the tested antibiotics were effective against all of the 45 isolated bacteria. The risk of contamination decreased with death-to-organ culture time (P=0.008) and was higher for corneas excised in situ than for those enucleated (P=0.02). Corneoscleral rims were sterile in 99.3% of the grafted corneas. Deswelling media were sterile in 100% of cases. A 19- to 53-fold decrease in the percentage of rim contamination was assessed with organ culture as compared with hypothermic storage (previous studies, P < 0.0001).

CONCLUSIONS

These results demonstrate the benefit of organ culture over hypothermic storage, because it allows contaminated tissue to be discarded.

Cryopreservation and culture of human corneal keratocytes

PURPOSE

To assess the effects of two different concentrations of albumin in a cryoprotective solution and two freezing methods on human corneal keratocyte ctyopreservation.

METHODS

Isolated keratocytes were used for cryopreservation. Solutions of 10% dimethylsulfoxide with either 2% or 10% human albumin were used as cryoprotective agents. Cells either were transferred directly into a -80 degrees C freezer (freezing rate, 2 degrees C/min) or were cooled in a programmed freezer (1 degrees C/min until -40 degrees C and then 10 degrees C/min), which resulted in four different cryopreservation protocols. Cells were stored at -80 degrees C, then were thawed at 37 degrees C, and subsequently were cultured. Keratocytes were studied by means of trypan blue staining, growth assay, apoptosis assays, transmission electron microscopy, and immunochemistry.

RESULTS

The percentage of cells that were alive after thawing ranged from 80% to 99% by trypan blue staining and from 45% to 60% by flow cytometry. The ratio of the number of living cells at the end of primary culture after cryopreservation to that before cryopreservation was significantly (P=0.04) higher after direct transfer into the -80 degrees C freezer than after controlled-rate freezing, whereas the albumin concentration had no significant influence on this ratio (P=0.45). The percentage of apoptotic cells was significantly higher after cryopreservation than in the control group of noncryopreserved cells; more than 5% 24 hours after thawing. Cryopreservation did not modify the keratocyte ultrastructure. Fibroblast growth factor dramatically decreased the serum-induced cell expression of alpha smooth muscle actin, whereas cryopreservation had no influence on this cell expression.

CONCLUSIONS

A freeze-thaw trauma, which was related to cryopreservation-induced cell apoptosis, was revealed during primary culture after thawing. Direct transfer into the -80 degrees C freezer resulted in better postcryopreservation growth in the culture than controlled-rate freezing. A change in albumin concentration from 2% to 10% did not affect the results.

Donor organ cultured corneal tissue selection before penetrating keratoplasty

AIMS

Donor organ cultured corneal tissue selection before penetrating keratoplasty is carried out by taking into account different variables. The objective was to identify preoperative variables which are significantly and independently associated with transplant outcome and should effectively be taken into account before transplantation.

METHODS

231 consecutive penetrating keratoplasties were prospectively studied using organ cultured tissue. Morphometric analysis of the donor corneal endothelium was performed before transplantation. Graft survival and endothelial cell density, during the second year following transplantation, were studied both at a univariate and multivariate level.

RESULTS

Recipient age, recipient rejection status, and preoperative diagnosis significantly influenced graft survival. Graft survival was higher when using corneal tissue from donors older than 80 years. Postoperative endothelial density decreased with preservation time and coefficient of variation after preservation. It increased with endothelial cell density after preservation and deswelling time, and correlated with preoperative diagnosis.

CONCLUSION

Organ cultured corneas with endothelial cell density after preservation < 2000 cells/mm2, and high coefficient of variation, may be discarded before transplantation. Corneas should be preserved for less than 3 weeks, and allowed to deswell before transplantation for 2 or 3 days rather than 1 day.

The complication of retained intraocular recipient corneal button after penetrating keratoplasty

PURPOSE

To describe the complication of retained intraocular recipient corneal button after penetrating keratoplasty.

METHOD

Case report. A 27-year-old man was referred to us because of complications after penetrating keratoplasty on the right eye. Slit-lamp examination disclosed a clear graft with a second clear corneal button behind.

RESULTS

A second penetrating keratoplasty was performed successfully on the right eye. Histologic examination showed an intact epithelium and stroma vascularization of the recipient corneal button. Immunochemistry of the recipient corneal button and the first donor corneal button was performed.

CONCLUSION

Although the recipient corneal button remained inside the anterior chamber for 5 months, no epithelial ingrowth occurred.

Endophthalmitis after Lasiodiplodia theobromae corneal abscess

BACKGROUND

Lasiodiplodia theobromae is an exceptional cause of human keratomycosis.

PATIENT

We treated a 53-year-old man with fungal keratitis, which had been treated with topical betamethasone and gentamicin for 1 month, and endophthalmitis due to Lasiodiplodia theobromae. Despite intensive systemic, topical and intravitreal fungicidal treatment, enucleation had to be performed.

RESULTS

The vitreous aspirate cultures were negative as of the second amphotericin intravitreal injection. However, histology revealed that the fungus was present in the cornea, ciliary body, iris and retina.

CONCLUSION

The use of topical steroids may worsen the outcome of the infection.

Evaluation of the deswelling period in dextran-containing medium after corneal organ culture

PURPOSE

To evaluate corneal structural modifications induced by the deswelling period in dextran-containing medium following organ culture.

METHODS

Twenty human corneas were organ-cultured for 2 weeks and subsequently incubated in Exosol deswelling medium (Opsia, Toulouse, France) for 1-4 days. Corneas were studied by means of light microscopy, morphometry, and transmission electron microscopy.

RESULTS

The deswelling period induced a statistically significant 8.4% endothelial cell loss and a 27.4% increase in the coefficient of variation. The endothelial layer remained intact. The basal epithelial cells displayed a flat appearance. Thin endothelial cells were observed in addition to dark vacuoles (the number of which increased with incubation time) with dense material and no mitochondrial swelling. Some basal epithelial cells and keratocytes were damaged on day 3 or 4.

CONCLUSIONS

Preservation injuries induced by 1 or 2 days of incubation in deswelling medium are moderate. Three or 4 days of incubation result in more severe dextran-induced injuries. Consequently, the deswelling period should not exceed 2 days.

ABO antigen blood-group compatibility in corneal transplantation

Our objective was to evaluate the effect of ABO antigen blood-group compatibility on corneal allograft rejection. The 199 penetrating keratoplasties performed between 1985 and 1994 were analyzed retrospectively for ABO compatibility and the occurrence of irreversible allograft rejection. Of these, 72 were considered high-risk transplants, as there was significant vascularization of the recipient cornea or a history of irreversible corneal allograft rejection or both. One hundred twenty-seven were low-risk transplants. The data were analyzed by using the Kaplan-Meier method and compared with the log-rank test. Overall, the estimated 1-year graft survival was 83.9% in the low-risk group and 61.4% in the high-risk group (p = 0.001). The estimated 1-year rejection-free graft survival was 89.8% in the low-risk group and 67.1% in the high-risk group (p = 0.0002). In the high-risk group, graft survival (p = 0.008) and rejection-free graft survival (p = 0.0002) were higher in the ABO-compatible subgroup than in the ABO-incompatible subgroup. In the low-risk group, graft survival and rejection-free graft survival of the ABO-compatible and ABO-incompatible subgroups were similar. ABO compatibility may be effective in preventing irreversible allograft rejection in high-risk recipients.

Measurement of Irregular Astigmatism Using Semimeridian Data from Videokeratographs

BACKGROUND

Irregular astigmatism is one of the most troublesome side effects of corneal surgery. We attempted to quantify irregular astigmatism in a simple way, using semimeridian data from videokeratographs of corneas with different amounts of irregular astigmatism.

METHODS

We studied the corneal topography of 30 normal corneas to be used as controls, 30 corneas from patients after radial keratotomy, 30 corneas from patients after nonfreeze myopic keratomileusis, and 30 corneas with clinically apparent keratoconus. We developed two diagnostic formulas, a refractive power symmetry index and an angle symmetry index, using the absolute-scale, color-coded map, and semimeridian data from the EyeSys Corneal Analysis System, and used them to compare the four groups of corneas.

RESULTS

In the corneas with irregular astigmatism, values for the refractive power symmetry index and angle symmetry index were significantly higher than in the normal corneas. The refractive power symmetry index confidence interval set at 95% was 0.58 diopters (D) (range 0.00 D to 0.58 D) in the control group. Using these limits, most values in the radial keratotomy, keratomileusis, and keratoconus groups were abnormal. Spectacle-corrected visual acuity correlated negatively with the refractive power symmetry index (rs = -0.58, p < .001). The refractive power symmetry index sensitivity and specificity were respectively 97% and 66%. Spectacle-corrected visual acuity did not correlate with the angle symmetry index.

CONCLUSIONS

Semimeridian data from videokeratographs can be used to quantify irregular astigmatism.

Modulation of HLA-DR and CD1a expression on human cornea with low-dose UVB irradiation

PURPOSE

To evaluate the effects of low-dose UVB irradiation of HLA and CD1a expression and the toxic effects of UVB on human corneas.

METHODS

24 pairs of human corneas from 24 donors were studied. One cornea from each pair was randomly irradiated with UVB (100 mJ/cm2) after enucleation. All corneas were then organ-cultured for 2, 7, 14 or 21 days. Endothelium was studied after enucleation and organ culture. Following preservation, corneas were evaluated by means of light microscopy, morphometry and TEM. HLA and CD1a staining was performed using an immuno-alkaline-phosphatase technique.

RESULTS

Endothelial cell loss during organ culture averaged 9.1% in the UVB group and 9.2% in the control group (NS). The number of rosette and reformation figures (p = 0.004) and the coefficient of variation (p = 0.014) were higher in the control group. Epithelial sloughing was more accentuated in the UVB group. We observed the same moderate ultrastructural injuries in both groups. In the epithelium, the average number of HLA-DR+ cells per field was 0.12 in the UVB group and 0.42 in the control group (p = 0.035). In the stroma, these figures were respectively 1.04 and 1.34 (p = 0.026). In the epithelium, the average number of CD1a + cells was respectively 0. 025 and 0.078 (p = 0.019). In the preservation mediums, the average percentage of CD1a + cells was 0.07% in the UVB group and 0.27% in the control group (p = 0.014).

CONCLUSIONS

Low-dose UVB (100 mJ/cm2) decreases HLA-DR and CD1a expression of organ-cultured human corneas and induces moderate corneal injuries. Low-dose UVB might be useful for preventing allograft rejection.

Morphology, histology, and ultrastructure of human C31 organ-cultured corneas

Our objective was to evaluate corneal structural modifications induced by corneal preservation in a C31 organ culture medium. Twenty-four postmortem human corneas preserved in C31 medium (CRTS, Besançon, France) for 2-21 days and 12 fresh postmortem human corneas were studied and evaluated by means of light microscopy, morphometry, and transmission electron microscopy (TEM). Endothelial cell loss during preservation averaged 9.2% (+/- 7.2%). Endothelial morphology displayed significantly more moderate alterations in the group of fresh corneas than in the group of preserved corneas. Endothelial morphometry resulted in a higher coefficient of variation (p = 0.002) in the preserved group but showed no difference for the average figure coefficient and average cell area. The histological study showed corneal swelling and epithelial sloughing in the preserved group. TEM displayed moderate preservation injuries, such as numerous vacuoles, mitochondrial swelling, and increased cell thickness. These results are consistent with previous findings that indicated that C31 medium induces moderate preservation injuries.