[Microbiological and serological verification of cornea donors]. / Vérification microbiologiques et sérologiques des donneurs de cornées.

A study was made during 1994 about microbiological contamination on the donor eyes before enucleation of whole globe. We studied the efficiency of the decontamination method by checking sterility of corneal storage medium after two days. We give results of serological tests on 252 donors.

[Medium term preservation of corneas. Comparative study of 4 preservation media]. / Conservation des cornées à moyen terme. Etude comparative de quatre milieux de conservation.

A comparative study of four preservation medium was made (Corneal Storage Solution, K-Sol, RPMI Hepes buffer, RPMI bicarbonate buffer). After a five days preservation delay there is no statistical difference between the percentage of the endothelial cellular mortality amongst the three first medium. In the fourth medium the cellular mortality is statistically higher. For longer preservation delay between 5 and 15 days, only the corneas preserved in K-Sol medium have a cellular mortality under 20% and could be used for keratoplasty.

Corneal endothelial cell density in acute angle-closure glaucoma.

The endothelial cell density of 44 eyes after an acute attack of angle-closure glaucoma is statistically lower than the cellular density of 174 control eyes. The decrease in endothelial cell density increases the risk of edematous corneal dystrophy, more specially after surgery (e.g. cataract extraction). The modifications in corneal endothelial cell density are compared with the alterations of the iris after a crisis of angle-closure glaucoma.

[Long-term study of endothelial cell density after penetrating keratoplasty. Comparative study of fresh and median-term preserved cornea]. / Etude à long terme de la densité cellulaire endothéliale après kératoplastie perforante. Etude comparative des cornées fraîches et conservées à moyen terme.

A retrospective specular microscopic study of 118 clear corneal grafts shows that the endothelium of these grafts is progressively destroyed during the two first years. The reduction of cellular density is rapid at the beginning of postoperative period, stabilizing after two years. The comparison of endothelial cellular density in fresh non selected grafts versus grafts preserved in culture seems to indicate a longer survival of preserved grafts. This study shows the utility of wide-field specular microscopy in the follow-up of clear corneal grafts. This technique furnishes useful information for postoperative management and long-term prognosis.

[Selection criteria and results of medium-term storage of corneas for keratoplasty (author's transl)]. / Critères de sélection et résultats de la conservation à moyen terme des cornées destinées à la kératoplastie.

A double-staining technique allowing calculation of the percentage of dead endothelial cells in corneas during medium-term storage is described. A positive correlation was found between the thickness of the cornea and the time since death, and between the percentage of dead endothelial cells and the thickness of the cornea. A negative correlation existed between age and cellular density of the endothelium. Conclusions of these data provides practical applications for the selection of corneas for keratoplasty.

[Keratoplasty. Urgent treatment of the corneal perforation (author's transl)]. / La kératoplastie. Traitement urgent de la perforation de la cornée.

Sixteen keratoplasties (15 perforating, 1 lamellar) were performed on 12 perforated corneas and on 2 eyes threatened by imminent corneal perforation. The causal disease was metaherpetic kératitis (6 cases), chronic and recurrent ulcers (4 cases), acute keratoconus (1 case) and corneal traumas (3 cases). Enucleation has been avoided and the anterior chamber was restored in all the cases, with or without anterior synechiae. One case only developed ocular hypertension which was cured by fistulisation. Architectonic results are satisfying in all the cases. Recuperation of visual functions is possible only in the most favourable cases. It is indicated to perform keratoplasty before the perforation when this one seems unavoidable and to consider this surgical procedrue as an emergency when the cornea is perforated.

[The effects of intraocular irrigating solutions on the human corneal endothelium (author's transl)]. / Effets de différentes solutions d'irrigation intraoculaires sur l'endothélium de la cornée humaine.

Human corneas from enucleated eyes get thicker during perfusion with B.S.S. On the contrary, their thickness decreases when perfused with T.C. Earle solution. Addition of reduced glutathion and adenosine does not change the results obtained with T.C. Earle. Histological study of the endothelium after a 24 hours perfusion demonstrates a better conservation of the cells with T.C. Earle and T.C. Earle glutathion--adenosine than with B.S.S.

[Pachymetry in the study of preservation of the cornea]. / La pachymétrie dans l'étude de la conservation de la cornée

Rabbit corneas were preserved for between 7 and 14 days at + 4 degrees C in a whole eye in synthetic media (T.C. 199 and T.C. Earle) with or without added Dextran. In the absence of Dextran the corneas preserved at + 4 degrees C became thick. This thickening increased with the length of conservation. Dextran limited the hydration of the stroma. Measurement of the variations of corneal thickness during perfusion for 6 hours at 30 degrees C in T.C. Earle could be used as an index of the function of the corneal endothelium. Even after 14 days of preservation at + 4 degrees C the corneal endothelium retained the ability to reduce or prevent hydration during perfusion at 30 degrees C. Histological studies showed good conservation of the cellular structure after 7 days at + 4 degrees C. Pyknosis appeared after 14 days conservation. T.C. 199 preserved endothelial function better than T.C. Earle.

[Histology and function of the cryopreserved corneal endothelium]. / Histologie et fonctions de l'endothélium des cornées cryopréservées

This work consists of a histological study of cryopreserved corneal endothelium before and after perfusion, and of measurements of the corneal thickness during perfusion. 1) Histoligical study: a) After 7 hours of perfusion, the endothelium of fresh corneas is unchanged. b) The preserving solutions used for freezing do not modify the histological structure of the endothelium. c) All the freezing and thawing processes described in this paper substantially alter the histological structure of the endothelium. Latent alterations are revealed during perfusion. 2) Pachymetric study: a) In the experimental conditions described, the fresh corneas keep their normal thickness for 7 hours of perfusion. b) The preserving solutions do not modify this property. c) After freezing and thawing the thickness of the perfused cornea increases rapidly. The thickness of the perfused cornea appears more slowly under the following conditions: 33 to 66 p. 100 of serum in the preserving solution, volume less than 1 ml; eutectic point between - 4 and - 6 degrees C; the duration of the plateau less than 4 min. speed of freezing after the plateau about 5 degrees C/min.