C. Allouch

Predicted Long-term Outcome of Corneal Transplantation

OBJECTIVE To analyze graft survival and the outcome of the corneal endothelium after corneal transplantation in a single model to predict the long-term prognosis of these grafts. DESIGN Cohort study. Data were recorded prospectively and then analyzed retrospectively. PARTICIPANTS One thousand one hundred forty-four consecutive eyes of 1144 patients who underwent corneal transplantation between 1992 and 2006. INTERVENTIONS Penetrating keratoplasty and deep anterior lamellar keratoplasty. MAIN OUTCOME MEASURES Slit-lamp examination and wide-field specular microscopy results. A joint analysis of endothelial cell loss and time to graft failure was undertaken. From midterm simultaneous analysis of graft survival and endothelial cell loss, long-term graft survival was predicted. RESULTS The observed 5- and 10-year graft survival estimates were, respectively, 74% and 64%. The average endothelial cell density (cell loss) was 2270 cells/mm(2) before surgery, 1058 cells/mm(2) (-53%) during the sixth postoperative year, and 865 cells/mm(2) (-61%) during the 10th postoperative year. Overall, the predicted graft survival estimate was 27% at 20 years and 2% at 30 years. Both observed and predicted graft survival were higher in patients who had undergone lamellar keratoplasty than in patients who had undergone penetrating keratoplasty and had normal recipient endothelium and higher in patients who had undergone penetrating keratoplasty and had normal recipient endothelium than in patients who had undergone penetrating keratoplasty and had impaired recipient endothelium. CONCLUSIONS For corneal diseases involving the endothelium, penetrating keratoplasty seems to be a good therapeutic approach in elderly patients because the graft life-span may be similar to the patient life expectancy. Conversely, for younger patients, penetrating keratoplasty is only a midterm therapeutic approach. For corneal diseases not involving the endothelium, deep anterior lamellar keratoplasty seems to be a promising therapeutic approach with higher long-term expected survival.

New test for the diagnosis of bacterial endophthalmitis

Background: Diagnosis of bacterial endophthalmitis (BE) often fails due to: (1) insufficient volumes of vitreous fluid (VF) and aqueous humour (AH); (2) lack of sensitivity of culture; (3) antibiotic treatments; (4) polymerase chain reaction (PCR) cross-contamination; and (5) limitations on the interpretation of the real-time PCR melting curve. We developed a fast real-time (f-real-t) PCR to improve the performance of the laboratory diagnosis of BE. Methods: The following samples were processed after adding an internal control: phosphate buffered saline (PBS); VF, AH and cell suspensions spiked with Bacteria (Bac); VF and AH from patients with endophthalmitis; and VF and AH from non-infective patients. DNA was extracted (MagNA Pure®) and added to four tubes containing selected primers and probes for the identification and quantification of all Bac and eight genera by f-real-t PCR. Diagnostic performances based on direct microscopic examination, culture and f-real-t PCR were compared. Results: The f-real-t PCR detected at least 0.01 colony-forming units (CFU) of Bac/μl with no cross-reactivity with fungi. Correlation with culture-positive results was 100%. Sixty per cent of BE samples tested culture-positive, but f-real-t PCR tested positive for 90%. Samples from non-infective cases were negative. Conclusion: The f-real-t PCR detected and quantified Bac, Staphylococci, Streptococci, Haemophilus, Pseudomonas, Enterobacteria, Acinetobacter, Propionibacteriacae and Corynebacteria in one run. Cultures required several hours to days (with a non-negligible number of false-negative results) and the f-real-t PCR was completed in 90 min. The f-real-t PCR is presented as a new tool for the diagnosis of BE: its usefulness requires validation with larger series of samples.

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.

Reproducibility of viscoelastic property and intraocular pressure measurements obtained with the Ocular Response Analyzer

Purpose:  To analyse the reproducibility of corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann‐correlated intraocular pressure (IOPg) and corneal‐compensated intraocular pressure (IOPcc) obtained with the ocular response analyzer (ORA).

Ocular Response Analyzer : étude de fiabilité et de corrélation sur des yeux normaux

Introduction Etudier la fiabilite des parametres de l’ORA (CH, CRF, IOPcc et IOPg) et leur correlation aux donnees biometriques de l’Orbscan ® (Orbtek, Bausch et Lomb, Salt lake City, Utah, Etats-Unis). Materiel et methodes L’Ocular Response Analyzer (ORA de Reichert, Depew, New York, Etats-Unis) donne la rigidite de la cornee (CH), son coefficient viscoelastique (CRF) ainsi qu’une pression intra-oculaire corrige (IOPcc). Les parametres de l’ORA ont ete etudies sur une population de 100 yeux normaux, puis correles aux donnees biometriques de la cornee mesurees a l’aide de l’Orbscan ® . Resultats Une bonne correlation et une faible difference des mesures entre les yeux droit et gauche ont confirme la fiabilite des mesures (r S = 0,84, p Conclusion Les valeurs normales et la repartition des facteurs biomecaniques sont equivalentes a ce qu’on retrouve dans la litterature et sont correlees aux donnees biometriques de la cornee (pachymetrie, diametre corneen). La nouvelle mesure de PIO corrigee est independante de la pachymetrie, mais n’est pas significativement differente de la PIO tonometrique a air donc son interet reste a demontrer.

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.

Late changes in refraction, pachymetry, visual acuity, and corneal topography after penetrating keratoplasty.

Purpose: To analyze the late changes in refraction, corneal topography, and pachymetry after penetrating keratoplasty. Methods: We have retrospectively analyzed data of 64 eyes of 56 patients with a clear corneal graft and no other ocular diseases. The eyes were examined soon and several years after all sutures were removed, at 19.5 ± 3.1 months and 76.8 ± 25.2 months, respectively, after keratoplasty. All eyes were examined using the EyeSys 2000 videokeratograph and the Tomey SP2000 ultrasonic pachymeter. Corneal surface regularity was studied using the indices provided by the Holladay Diagnostic Summary (ie, asphericity coefficient Q; corneal uniformity index CU; predicted corneal acuity PCA). Irregular astigmatism was quantified using semimeridian data from videokeratographs (refractive power symmetry index). Results: Visual acuity increased by an average of 0.35 ± 0.93 lines (P = 0.002) between the 2 examinations, whereas no significant changes in refraction and videokeratoscopy (ie, power, indices, and irregular astigmatism) were observed (P ≥ 0.08). Central corneal thickness significantly increased from 542 ± 31 μm to 572 ± 38 μm (P < 0.001). Change in BSCVA did not significantly correlate with the change in refraction, in topographic indices, or in irregular astigmatism (rs ≤ 0.13; P ≥ 0.16). Conclusion: Late after penetrating keratoplasty, best corrected visual acuity shows a small but statistically significant improvement, whereas refraction and corneal surface regularity are stable. This late improvement in visual acuity is not explained by current techniques.

Analyse biométrique par Orbscan et échographie du glaucome aigu par fermeture de l’angle

PURPOSE: To study acute-angle-closure glaucoma (AACG) biometry using Orbscan and echography. MATERIAL AND METHODS: We prospectively studied 200 normal eyes of 100 patients (including eyes with ametropia), 50 eyes of 25 patients before peripherial YAG laser iridotomy, 25 phakic eyes of 25 patients with a history of acute-angle-closure glaucoma (AACG) in the fellow eye. Both plane and polynomial modes of reconstruction of the iridocorneal angle measurement were analyzed. Biometric measurements of the three groups were compared. Biometric measurements (i.e., iridocorneal angle, anterior chamber depth, axial length, and lens thickness) and subjective spherical equivalent were correlated with the etiological classification. RESULTS: Age, sex, iridocorneal angle, anterior chamber depth, lens thickness, axial length and subjective spherical equivalent were significantly different in the three groups (p 0.51; p<0.001) and with the etiological classification (rs< or =0.68; p<0.001). The anterior chamber depth measurement obtained by Orbscan or echography was the best parameter for predicting ACCG (rs=0.77; p<0.001). CONCLUSION: The anterior chamber depth and polynimial iridocorneal angle obtained using the Orbscan device appears to be useful in predicting acute-angle-closure glaucoma.

Biométrie oculaire par Orbscan

Orbscan is a recent optical device that combines the Placido disk of the videokeratoscope and a scanning slit. The scanning slit measures the elevation of both the corneal surface (anterior and posterior) and the anterior iris-lens surface. Biometric measures of the anterior segment such as corneal thickness, anterior chamber depth, corneal diameter, and iridocorneal angle are obtained using spatial coordinates of various ocular surfaces. Orbscan is not only a corneal topograph but a versatile device capable of measuring the biometry of the anterior segment of the eye.

Étude biométrique du cristallin par échographie A et Orbscan

Objectif Nous avons etudie la biometrie du cristallin a l’aide de l’echographie en mode A et de l’Orbscan. Materiel et methodes Nous avons analyse prospectivement la biometrie du cristallin de 280 yeux normaux, en dehors d’une eventuelle ametropie, de 140 patients âges de 10 a 95 ans. L’epaisseur centrale du cristallin et le rayon de courbure anterieur du cristallin ont ete respectivement mesures a l’aide de l’echographie en mode A et de l’Orbscan. Ces deux parametres biometriques du cristallin ont ete correles a la mesure controlaterale, a l’âge et au sexe du patient, a la refraction subjective et aux autres parametres biometriques de l’œil : la profondeur de la chambre anterieure, l’angle irido-corneen, le diametre corneen, l’epaisseur corneenne, le diametre pupillaire, les rayons de courbure corneens anterieur et posterieur et la longueur du segment posterieur. Resultats Le rayon de courbure anterieur du cristallin n’etait correle a aucune autre variable (et en particulier, pas a l’equivalent spherique), mais la qualite de la mesure etait mediocre. En effet, la reproductibilite de cette mesure etait faible (14,4 % de difference entre deux mesures successives). La correlation avec l’œil controlateral etait faible (r s = 0,55 ; p s = 0,97 ; p s = 0,82 ; p s = - 0,72 ; p s = - 0,65 ; p s = - 0,68 ; p s = - 0,62 ; p Conclusion L’epaisseur du cristallin est principalement influencee par l’âge et est correlee a la profondeur de la chambre anterieure et a la mesure de l’angle irido-corneen. L’influence du vieillissement sur la biometrie du segment anterieur de l’œil se traduit essentiellement par une augmentation de volume du cristallin.PURPOSE To analyze the lens biometry obtained by Orbscan and A-scan ultrasound in normal eyes. MATERIAL and methods: The lens thickness obtained by A-scan ultrasound and the anterior curvature of the crystalline lens obtained by Orbscan were prospectively recorded in 280 normal eyes (including eyes with ametropia) of 140 patients (10-95 years of age). The correlation of lens biometry with the contralateral measure, patient age and sex, subjective refraction, and other ocular biometric parameters (anterior chamber depth, iridocorneal angle, corneal diameter, central pachymetry, pupil, corneal radii of curvature, and posterior segment length) was assessed. RESULTS The lens anterior curvature showed no significant correlation in particular with the subjective spherical equivalent; however, the quality of this measure was poor: the reproducibility of the lens anterior curvature was low (the average difference between two successive Orbscan measurements was 14.4%). The correlation with the contralateral eye was poor (rs=0.55; p<0.001 versus rs=0.97; p<0.001 for lens thickness). Lens thickness showed the strongest correlation with the patients age (rs=0.82; p<0.001); it increased by 0.26 mm per decade. Lens thickness correlated with anterior chamber depth (rs=-0.72; p<0.001) and iridocorneal angle (rs=-0.65; p<0.001). The last two parameters also correlated with age (rs=-0.68; p<0.001 and rs=-0.62; p<0.001, respectively). Anterior chamber depth and iridocorneal angle decreased by -0.21 mm and -1.7 degrees , respectively, per decade. CONCLUSION Lens thickness is mainly influenced by age and correlates with the anterior chamber depth and the iridocorneal angle. The influence of aging on anterior segment biometry essentially consists in an increase in lens volume.