Retinal folds through the macula.

In a series of 137 consecutive conventional primary retinal detachment repairs we postoperatively found retinal folds through the macula in four cases (2.8%). All four patients had presented with an acute, bullous, superior detachment, and had been treated with an encircling band, drainage of subretinal fluid, injection of an air/gas mixture, cryocoagulation, and a radial buckle to close the largest retinal tear. Redundant retina (created by the encircling band and possibly by stretching in the bullous detachment) became folded either by compression by the gas-bubble in the recumbent patient, or by a steam roller action of the bubble when the patient sat up. In acute bullous detachments, we try to avoid this complication by using an air/gas bubble which is not greater than necessary to tampon the retinal break, and by positioning the patient in such a way that residual subretinal fluid is pressed away from the posterior pole.

Fungal growth on soft contact lenses: a SEM-study.

Three soft contact lenses of the HEMA type, discarded because of irritation of the cornea, were processed for and subsequently examined with the SEM, A large portion of the convex surface was covered with globular deposits of fungal spores. Cross-fractures of lenses showed penetration of the fungi into the matrix material of the lenses. The concave surface of the contact lenses showed at two points imprints of the epithelial cells of the cornea in the deposited material on that side of the lenses.

A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

A SEM-study of a keratoconus and an artificially aged human cornea.

The substructure of both the epithelial and endothelial surfaces of a keratoconus and an artificially aged cornea was compared with that of a healthy cornea by investigating them with a scanning electron microscope. From the depressions around the protruding centre of the epithelial surface of the keratoconus cornea, and from the whole epithelial surface of the artificially aged cornea, cells detached themselves, assuming a more or less rounded shape. The endothelial surface of both the keratoconus and the aged cornea showed areas of cells with an almost completely disintegrated cell membrane, exposing the cell contents. On the endothelial surface of the keratoconus cells were found with a missing cell-nucleus and a perforated cell membrane, due to a 'Kammerwasser Einbruch' effect.

Mechanical and biochemical effects of man-made fibres and metals in the human eye, a SEM-study.

Prolene, perlon, supramid and titanium, either used as sutures, 'Strampelli' sutures or artificial lens loops, were compared after remaining in the human eye for at least one year. For comparison, non-implanted samples of each of the materials were used as blanks. Prolene and Perlon in particular showed severe biodegradation after a given period; Supramid showed much less degradation of its surface. Titanium showed a rather rough outer surface (even in the non-implanted samples), particularly as bends in the lens loop, which facilitated the adherence of cells, fibres and microorganisms.

Membrane formation and endothelial cell growth on an intra-ocular lens in the human eye, a SEM study.

In this study we have demonstrated the formation of an acellular and a cellular membrane on the surface of an explanted intra-ocular lens by scanning electron microscopy. The acellular membrane is considered to be the result of a physiological process, whereas the cellular membrane is looked upon as a pathological endothelial membrane formed as the result of intermittent touch between the implant and the endothelium.

A keratoprosthesis successfully implanted in the cornea of a rabbit, a SEM-study.

By means of a new fixation technique keratoprostheses were fixed in the cornea of 'Hollander' rabbits. The fixation is based on the use of corneo-sclerally orientated stainless steel-vanadium traction threads in corneal stroma and scleral tissue. Keratoprostheses placed according to this fixation technique have a follow-up of a maximum of two years. The liquid sealing capacity, the cell behaviour on the surface of the prosthesis and the anchoring of the stainless steel vanadium wire have been investigated in detail with the scanning electronmicroscope (SEM).