The significance of some observations on African ocular onchocerciasis described by Jean Hissette (1888-1965).

One of the most significant contributions to tropical medicine and ophthalmology was made by Jean Hissette: African ocular onchocerciasis. During his extensive investigations in the Babindi country, he found numerous adults with river blindness. Their eye disease was caused by the filaria Onchocerca volvulus Leuckart. He noticed the signs of interstitial keratitis and band keratopathy, faint iritis or iridocyclitis, posterior synechiae and often a downward distortion of the pupil. He was the first to describe chorioretinal scarring of the fundus, what became known as the Hissette-Ridley fundus. People reported to him their entoptic phenomena which he unequivocally interpreted to be the images of microfilariae in the patient's own eye. During his stay in Belgium in 1932, he elucidated the pathogenesis of blindness since he was able to provide histological proof of the presence of microfilariae in various ocular tissues of an enucleated eye from a patient living near the Sankuru river. Like other serious health impairments, the severe inflammatory lesions in the eye occurred only after the microfilariae had died. Hence he realized that dying microfilariae play a key role in the mechanisms leading to blindness. Hissette's precise descriptions were the logical fruit of his outstanding observational abilities and enabled him as a man of great intuition to speculate about causal relationships. He evidently benefited from the fact that he took the native Africans seriously and asked them their opinion. In 1933, his friend and teacher Dr. De Mets in Antwerp already wrote on Hissette's discovery in the Belgian Congo: "This study is of exceptional value to specialists which is not only a tribute to its author, but to our common native country (Belgium)."

[Ocular onchocerciasis: a key role for Wolbachia]. / Okuläre Onchozerkose: Wolbachien haben eine Schlüsselrolle.

Onchocerciasis is caused by the parasitic worm Onchocerca volvulus, which releases millions of offspring (microfilariae). Microfilariae migrate through the skin and can enter the anterior or posterior regions of the eye. While alive, the microfilariae appear to cause little or no inflammation, being in the anterior chamber. However, when they die, either by natural attrition or after chemotherapy, the host response to degenerating worms can result in ocular inflammation (keratitis, uveitis, chorioretinitis, neuritis of the optic nerve) that causes progressive loss of vision and ultimately leads to blindness. With the use of a mouse model of corneal inflammation to study the pathogenesis of ocular onchocerciasis by injecting worm extracts directly into the corneal stroma, it was found that worms treated with the antibiotic doxycycline, which destroys Wolbachia, induced lower corneal stromal thickness and stromal haze (indicators of corneal oedema and opacity) and neutrophil infiltration compared with both untreated worms and worms that do not harbour Wolbachia. These data indicate that endosymbiotic Wolbachia bacteria in filarial parasites have a key role in the pathogenesis of river blindness. Worms recovered from patients treated for 6 weeks with doxycycline contained fewer Wolbachia bacteria and had abnormal embryogenesis, indicating a role for Wolbachia in the survival or fecundity of the worms. Antibiotic treatment may also reduce the severity of the inflammatory response in the cornea.

[Pattern-induced after effects caused by an on-screen workstation]. / Musternacheffekte durch den Bildschirmarbeitsplatz.

Millions of people work or spend their free time sitting in front of VDUs that induce contingent visual effects. However, only a few notice irritations in the course of everyday work: motion after-images such as the waterfall illusion or tilt after-effects are possible. A new effect may be caused by those new VDU monitors which have an almost square pattern in the display matrix in which the vertical lines are thicker than the horizontal lines. After-images persisting for days are described when this pattern has an edge length of 0.3 mm and over. These effects are of little concern to most users of VDUs.

[Psychogenic blindness caused by a command to kill]. / Psychogene Erblindung durch einen Befehl zum Töten.

Corporal H.M. was detailed to shoot Jews as a member of a firing squad in 1941 during the German advance in White Russia. First at all, a shooting practice was to take place on the subsequent day. He became blind in his right eye overnight and as a right-handed marksman was no longer able to shoot properly. He was transferred to the front, where he was wounded. He spent 18 months in military and civil hospitals and a sanatorium until he was discharged from the army in the middle of the war because of his weak vision and "autonomic vasomotor neurosis". His psychogenic amblyopia lasted 52 years until he was afflicted with amaurotic blindness in his left eye owing to an attack of glaucoma which had not been treated in time. The vision of his right eye increased again for the first time to 0.1 (10%), but remained reduced owing to a brunescent cataract.

[In vivo measurement of the distribution of the refractive index of the human lens using a Scheimpflug photo of the anterior eye segment and a helium-neon laser beam]. / In-vivo-Messung der Brechungsindex-Verteilung der menschlichen Linse mit Hilfe eines Scheimpflug-Fotos des vorderen Augenabschnitts und einem Helium-Neon-Laserstrahl.

The distribution of the refractive index of the human lens in vivo is measured by taking a Scheimpflug photograph of the anterior segment while simultaneously passing a HeNe laser beam through these structures. The refractive index can be evaluated simply by using the Snellens formula for refraction on the course of the beam after reevaluating the Scheimpflug photograph for distortion. It is possible to perform this measurement during accommodation and in the relaxed lens.

Fundus polaroid screening for diabetic retinopathy. Is one print per patient enough?

The CR3-45 NM Canon nonmydriatic fundus camera detects relevant diabetic retinopathy with high sensitivity. To determine whether examination of one eye per patient would suffice for screening purposes, 473 pairs of standard 45 degree fundus Polaroid prints obtained with the Canon camera were assessed from 167 patients with and 306 without diabetic retinopathy. On the basis of considering only one eye per patient, absence of retinopathy would have been diagnosed in 336 patients, with 9% of the diagnoses false negative. One hundred thirty-seven of the 167 patients with retinopathy in at least one eye would have been diagnosed correctly by considering one eye per patient (sensitivity 82%, specificity 100%). Thus, a standard 45 degree fundus Polaroid print from one eye per patient may suffice for screening purposes if the picture is free from diabetic abnormalities. Otherwise, both eyes should be examined immediately, and the patient should be referred to an expert ophthalmologist who specializes in diabetic retinopathy for confirmation of the diagnosis and staging of diabetic retinopathy status.

Lesion and regeneration of the anterior and posterior lens capsule and cortex in rabbits Nd:YAG laser.

With a mode-locked Nd:YAG laser set at various energy levels, anterior and posterior capsular and cortical lesions were produced in the lens of rabbits. Biomicroscopic and Scheimpflug examinations showed the anterior lesion to be healing in a whitish scar that was restricted to the area of the original lesion. Histology and transmission electron microscopy (TEM) demonstrated the proliferation of epithelial cells that produced a new, continuous, basement membrane-like capsule. In the area of the lesion collagenous material, myofibroblast-like cells and macrophages were found. Laser-induced lesions in the posterior lens capsule and lens protein resulted in damage to the capsule and grey opacity of the lenticular proteins, which remained unchanged for 6 weeks. Neither inflammatory nor epithelial cells appeared within the locally damaged lens. Macrophages migrated from the vitreous into the lesion; they were observed either in intercellular clefts or within a lens fibre, almost completely taking up their cross section.

[Evaluation of Scheimpflug photographs in transitory hypermetropia]. / Auswertung von Scheimpflug-Photos bei einer transitorischen Hypermetropie.

Scheimpflug photography of lenses with transient hypermetropia in cases of diabetes mellitus revealed an enlargement of the axial diameter of the cortex and especially of the nucleus of the lens. This transient hypermetropia is thought to stem from a decrease in the refractive index of the lens cortex and nucleus.

Retinal blood vessel test in young-onset diabetic patients.

136 patients with insulin-dependent diabetes mellitus (IDDM) were shown the entoptic blood vessel figure. All patients were examined independently by retinal fluorescein angiography and ophthalmoscopy. 34 patients had no retinopathy, none of them believed to see alterations. 102 patients had different phases of diabetic retinopathy. If there were 1-5 microaneurysms within the 15 degrees meridian surrounding the central fovea, 55% of the patients were able to detect their alterations. If there were 6-20 microaneurysms, 77% of the patients were able to diagnose them. 90% of the patients with an even more severe retinopathy could see their abnormalities. Obviously there are no incorrectly positive results. For intelligent and well-observing patients with IDDM the retinal blood vessel test is a useful method for early detection and self control of diabetic retinopathy. Nevertheless, control of the fundus by an ophthalmologist is still necessary.

[Monocular polyopia in nuclear cataract]. / Die Polyopia monocularis bei Kernkatarakt.

Only patients with primary nuclear cataracts perceive multiplied images caused by the lens. All of them see these images in a lambda-shaped arrangement. This is not a diplopia caused by the two focal points of a 'Linse mit doppeltem Brennpunkt' (double-focus lens). The monocular polyopia can be explained by a prismatic effect of the sectors of the lens nucleus.

[Retinal findings in the hereditary persistence of fetal hemoglobin and glucose-6-phosphate dehydrogenase deficiency (G-6-PD deficiency)]. / Retinabefunde bei hereditärer Persistenz fetalen Hämoglobins (HPFH) mit Glucose-6-phosphat-Dehydrogenase-Mangel (G-6-PD-Mangel).

Peripheral arteriolar occlusions of the retinal vessels and the 'black sunburst sign' as the first stage of sickle-cell retinopathy (Goldberg 1976) were found in a 34-year-old black patient from West Africa with hereditary persistence of fetal hemoglobin (HPFH) and glucose-6-phosphate dehydrogenase deficiency (G-6-PD-D). The patient's son was found to have HPFH without G-6-PD-D, his daughter HPFH as well as G-6-PD-D. Ophthalmoscopic findings in the two children were normal. In the mother - a white German without clinical symptoms - neither HPFH nor G-6-PD-D were found. This is the first description of the typical picture of 'sickle-cell retinopathy' in a patient with HPFH combined with G-6-PD-D. HPFH is not associated with any retinal symptoms or hematological abnormalities. Hemolytic crises induced by fava beans or drugs in G-6-PD-D alone lead to different ocular complications from those found in this patient.