Harold E. Henkes

Unsaturated fats and progression of diabetic retinopathy

Two groups of adult-onset diabetics, matched according to 10 different criteria, were followed, biochemically and fluorescein-angiographically, over a period of 6 years. One group used a saturated-fat diet, and the other group of patients were on an unsaturated-fat diet, particularly rich in linoleic acid.Statistically significant differences were found in biochemical data and in the progression of diabetic microangiopathy between the two groups.The conclusion is warranted that a linoleic acid-rich diet, administered over an extended period of time, may inhibit the development of microangiopathy, or the deterioration of diabetic retinopathy.

Herman Snellen (1834–1908) and Müller’s ‘Reform-Auge’

The shell prothesis, originally meant to be placed over the atrophic eye, caused serious problems when used after enucleation, which became more common practice in the second half of the last century. In the nineties of the last century Snellen Sr. tried to solve these problems by designing a light prothesis that filled up the empty space. At the insistence of Snellen, the Müller brothers in Wiesbaden succeeded in 1892 to blow a hollow artificial eye which proved to be a real success.

Photic injury to the retina and the manifestation of acute posterior multifocal placoid pigment epitheliopathy.

Findings in retinas of animals suggest a correlation between the pathological process of certain hereditary dystrophic diseases and the effect of light on the retina. One may speculate whether clinical conditions exist — apart from hereditary retinal dystrophies — in which the retina becomes more sensitive to light from strong artificial or natural sources, which are otherwise innoxious.Two case histories will be presented, clinically diagnosed as acute posterior multifocal placoid pigment epitheliopathy in which a direct relationship seems to exist between the appearance of the fundus changes and the light impact.The role of electrodiagnostic procedures in the differential diagnosis will be discussed.

Electrodiagnostic procedures in drug-induced ocular diseases

Modern electrophysiological methods like electro-oculography (EOG), electroretinography (ERG) and visually evoked cortical responses (VER) enable us to determine objectively the localization and the extent of drug-induced diseases in many cases.Sometimes more information can be obtained when advanced examination methods, such as the local foveal ERG, are used. The objective examination methods mentioned above are not the only techniques to rely on when the early diagnosis of drug-induced diseases is concerned. These methods have to be supplemented by other objective and psychophysical examination methods.Follow-up of electrodiagnostic results may be quite helpful in giving a reliable prognosis in drug-induced ocular diseases.

Advances in Electro-Ophthalmology its Use in Retinal Vascular Diseases

Since KARPE (1946) published his thesis ‘Basis of clinical electroretino-graphy’ the field of electro-ophthalmology has much expanded.

Fundus changes in primary hyperlipaemia.

The retinal vascular change described for two relatively young men and initially diagnosed as arteritis retinalis but subsequently regarded as an analogue of retinal lipaemia stresses the importance of biochemical exploration for a possible disturbance in the fat metabolism in unclear cases of retinal vasculopathy. If a disturbance in the fat metabolism is found, rational therapy will lead to disappearance of the vascular mural changes.

Antonie Cramer's explanation of accommodation

In the middle of the last century the question of the origin of accommodation was still unsolved. At the suggestion of Donders, Cramer used in 1851 a microscope to demonstrate that accommodation has to be ascribed to an increase in the curvature of the lens. Donders himself had several instruments made for the same purpose. These are still present in the collection of the Royal Netherlands Ophthalmic Hospital.

On the poor legibility of the captions in musea.

In the museum world, designers in general hardly take into account the legitimate wishes of elderly visitors, whose visual acuity is often less than optimal, with regard to the legibility of the captions by paintings or in show-cases. The conditions necessary for letter and word recognition, the influence of illumination, contrast and colour are discussed. Test-cards for use in musea, and the recruiting of a representative test-group of senior citizens, are recommended.

The Utrecht ophthalmic hospital and the development of tonometry in the 19th century

During the second half of the 19th century Donders, Snellen and co-workers of the Utrecht Eye Clinic played an important role in the development of clinical tonometry. These indefatigable researchers designed and built a number of tonometers of which most have been saved and which are now on display in a permanent exhibition in the Royal Netherlands Ophthalmic Hospital at Utrecht.

Helmholtz, the first reformer of ophthalmology

Helmholtz’ invention of the ophthalmoscope in 1850 was a case of serendipity, the gift of being able to make discoveries by pure accident. The theory of the glow seen in the pupil of the eye in the dark was formulated by Helmholtz’ friend and colleague Brucke, who observed this phenomenon while studying the eyes of their mutual friend, Emil du Bois-Reymond (1818–1896; Fig. 1). Brucke, du Bois-Reymond and Helmholtz were very close friends; all three were physiologists and about the same age, at the time of Helmholtz’ invention and they lived in or near Berlin.