[Preliminary results of the pterygium excision technic with conjunctival autograft]. / Résultats préliminaires de la technique d'excision du ptérygion avec autogreffe conjonctivale.

14 eyes with a pterygium, including one eye from which a pterygium had previously been removed by a simple excision, underwent a conjunctival autograft. During an average follow-up of 13 months, we observed a recurrence in 5 eyes (35%). The visual acuity stayed unchanged in 10 eyes, worsened in 1 eye and improved in 3 eyes. The corneal astigmatism measured with a Javal keratometer showed a modification in 12 eyes. This method should not be used as a standard primary surgery for pterygium in view of the high recurrence rate observed.

Immunocytochemical localization of gentamicin in the rabbit retina following intravitreal injection.

The localization of gentamicin in the retina after a single intravitreal injection in the rabbit eye was examined by indirect immunofluorescent staining with goat antigentamicin antiserum. Eight hours after the injection of 400 micrograms of gentamicin, staining was observed in the ganglion cell layer, the inner plexiform layer, the inner nuclear layer, and the photoreceptors. By 12 hours, the staining was also observed in the retinal pigment epithelium. Howeever, by 24 hours the staining was predominantly found in the retinal pigment epithelium and choriocapillaris, and only occasional staining was seen scattered in the neurosensory retina. At 36 to 48 hours, the labeling was confined to the retinal pigment epithelium and choriocapillaris. Electron microscopy confirmed the cytoplasmic localization of gentamicin in the retina.

Gentamicin toxicity in the primate retina.

To study the toxic effect of aminoglycoside antibiotics in the primate retina, gentamicin sulfate was injected into the center of the vitreous cavity of Cebus navrigatus monkeys. At a dose of 1000 to 3000 microgram, a picture consistent with apparent macular infarction appeared on fundus examination and fluorescein angiography by three days and gradually faded by 21 days. While light and electron microscopic examination of the retina showed no primary vascular lesions, striking damage to the inner retinal layers, mainly the nerve fiber layer, ganglion cell layer, and the inner plexiform and nuclear layer, was seen. Less severe effects in the outer retinal layers and the retinal pigment epithelium occurred. These observations suggest that the neurotoxic effect of intravitreal gentamicin was sufficient to cause a complete shutdown of the regional blood flow, perhaps by the mechanism of granulocytic plugging of the capillary bed. Although this toxic effect occurred at doses considerably in excess of what has been recommended for clinical use in humans, the "safe" dose of intravitreal gentamicin, nevertheless, remains to be established unequivocally.

[Lamellar corneal graft in the treatment of pterygium. A 10-year retrospective study of the recurrence and changes of astigmatism]. / La greffe lamellaire cornéenne dans le traitement du ptérygion. Etude rétrospective sur 10 ans des taux de récidives et de la modification de l'astigmatisme.

57 eyes with a pterygium, including 12 eyes (22%) from which a pterygium had previously been removed by a simple excision, underwent a corneoscleral lamellar excision of pterygium followed by a corneal lamellar keratoplasty. During a mean follow-up of 37 months, we observed a recurrence in 2 eyes (3.5%). The corneal astigmatism measured with a Javal keratometer showed a modification in 54 eyes (95%). Visual acuity improved in 4 (7%) eyes, was unchanged in 29 (51%) and deteriorated in 23 (40%) eyes. The benefits of the low recurrence rate after this surgical procedure are to be weighed against the risk of modification of the corneal astigmatism and the possible modification of the visual acuity.

Reduced number of hemidesmosomes in the corneal epithelium of diabetics with proliferative vitreoretinopathy.

Morphometry on transmission electron micrographs of the hemidesmosomal width was related to the length of the basal plasmalemma in corneal epithelium biopsy specimens. The basal plasmalemma length occupied by hemidesmosomes showed a mean fraction of 0.227 in eight patients undergoing cataract extraction or vitrectomy for diabetic proliferative vitreoretinopathy. In seven non-diabetic control patients of comparable age and sex undergoing cataract or pterygium surgery, 0.412 of the basal plasmalemma was covered by hemidesmosomes. A reduction in hemidesmosomes (P less than 0.001) may contribute to a weakness in the adhesion of diabetic corneal epithelium to the underlying stroma.

Residual bodies in the retinal pigment epithelium induced by intravitreal netilmicin.

Intravitreal injection of aminoglycoside antibiotics is known to induce morphological changes in the retinal pigment epithelium (RPE) resembling a lipidosis. The RPE of netilmicin-treated rabbits displays a dose-related increase in autofluorescence compared to untreated controls. Netilmicin produces an accumulation of membrane-limited osmiophilic lamellated inclusions in the pigment epithelial cell. These inclusions measure from 1 to 3 microns in diameter, and have acid hydrolase activity demonstrated by cytidine monophosphate cytochemistry. These findings suggest that netilmicin-induced inclusions are residual bodies and that the accumulation of these residual bodies is responsible for the observed cellular lipidosis.

Experimental drusen formation induced by intravitreal aminoglycoside injection.

A single intravitreal injection of aminoglycoside antibiotics in the rabbit induces changes in the retinal pigment epithelial layer that consist of disseminated yellow-white dots that are apparent six to ten months after injection. With fluorescein angiography, these dots have the characteristics of window defects or drusen. Histologic examination disclosed subepithelial amorphous material that stained positively with both periodic acid-Schiff and oil red O. Ultrastructural examination disclosed lipidic inclusions in the retinal pigment epithelial cells, basally directed cellular evagination, and basal accumulation of granular material, findings consistent with the reported morphologic features of hard drusen. These findings suggest that aminoglycoside-induced lesions may represent a model for retinal pigment epithelial degeneration and drusen formation.

[Langerhans cells and corneal neovascularization in experimental alkali burns]. / Cellules de Langerhans et néovascularisation cornéenne dans les brûlures alcalines expérimentales.

Experimental alkali-burns rabbit corneas present a neovascularisation. Six weeks later the corneas have been processed for ATPase Cytochemistry, allowing the observation of Langerhans cells. We observed an increase in the number of Langerhans cells that was statistically significant in alkali-burned corneas when compared to unburned corneas in the peripheral and midperipheral cornea.