Experiences with early contact lenses and some of their later developments.

CONTACT lenses have interested me for a long time. A few years after the first world war I obtained some blown ones from Muller of Wiesbaden and managed to insert one under my eyelids. I did not know at that time about filling the lens with some saline and the visual and cosmetic results were such that they discouraged me from making further experiments. Zeiss contact lenses became available a few years later and I borrowed a trial set with varying corneal and scleral radii. The optical effect in these was obtained by variations in the radius of the corneal portion, no lens being ground on them, and one went on trying different lenses to obtain the optimum result. I have no figures regarding toleration, but so far as I remember, this never exceeded a few hours. Two cases remain in my mind. One was that of a patient with 3 or 4 D of astigmatism, in whom fitting the contact lenses was like trying to make half a walnut shell fit on to the back of a spoon, and it was not possible to prevent large bubbles forming inside the lens. The other was that of a woman who was managing to wear her lenses fairly well. She rang me up one Sunday morning, however, and said she had had her lenses in for some time and that one eye had become foggy, She also mentioned that if she looked at a light she saw haloes round it. I thought that she must have developed glaucoma and asked her to come up and see me. The cornea was obviously hazy and when I removed the contact lens, the epithelium looked oedematous. The ocular tension was normal, however; there was no pain and the cornea cleared a few hours after the lens had been removed. This condition became well known later on through the work of Sattler, and was called Sattler's veil. The aetiology was at first obscure but became clear eventually when it was found that the veil failed to develop if a small ventilating hole was made in the contact lens. This allowed the metabolic products of the cornea to escape and to be replaced by fresh lacrimal fluid thus preventing alterations in its pH. In the autumn of 1936, before the cause of the veil had been discovered, I heard of thework of Dallos, who was taking moulds of the eyeball, and three of us spent a fortnight in his clinic at Budapest in an attempt to learn his method of fitting contact lenses. We learnt quite a lot, but not enough to enable us