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Dr. Welsh states that he has gone into a strange field to learn the terminology used, and that the terms used throughout his paper are those which he encountered. This paper deals with some of the elementary but serious problems of corneal contact lens fitting which are unique to the aphakic family of corneal contact lenses. The development of the lenticular cut form of the corneal contact lens is what has made contact lenses become so successfully fitted in such strong-plus prescriptions as those that correct aphakic refractive errors. The Figure demonstrates some of the specifications of this lenticular cut type of aphakic-powered corneal contact lens. 1. This is a corneal lens whose over-all diameter is 10.0 mm. Aphakic corneal lenses vary from 9.6 to 10.8 mm. in diameter—occasionally more or less than these dimensions. 2. The lenticular optic portion is 8.0 mm. here and varies from 7.0 to

Contact lens wear generally induces changes of corneal curvature as measured with the keratometer. Previous studies have considered only one dimension of the curvature change or the fir of the lens. This paper introduces a graphical system in which a co-ordinate system is used to express two dimensions of the lens to cornea fitting relationship. A vector from the initial mode of fit point gives a two dimensional expression of curvature change. There are suggestions on statistical analyses of data plotted on this graphical system.

The characteristic symptom is a severe pain in one eye, on waking from sleep, usually occurring some weeks after abrasion by a finger nail, piece of paper, or branch of a shrub, but relatively seldom after removal of an industrial foreign body. The pain tends to improve during the day, and may last several days and then disappear to return after another interval. At other times the pain may be continuous but of varying severity, or the patient may feel as though he has something in the eye. A symptom infrequently described, but of considerable significance, is pain or tenderness on rubbing the eye-this is likely to be noted while drying the face after washing.

This paper outlines the problems of photocoagulating the extreme fundus periphery. It describes two new contact lenses which permit precise visualization for examination, photography, and photocoagulation of the extreme periphery. They can also be used for examination and photography of the anterior chamber angle. Photographs of the peripheral fundus, the ciliary body, and the anterior chamber angle are taken through the new contact lenses with a hand fundus camera (Kowa).

Electroretinography (ERG) is well known as an aid in establishing diagnosis in several eye diseases and in serving as a tool for pure research. Response, of course, depends on such variables as light source (stimulus), apparatus, size of the pupil, and location of the area of retina which is stimulated; it is also important that records be obtained under constant standard conditions. The purpose of this paper is to describe a contact lens for use in recording the ERG in rabbits (Fig. 1). The contact lens developed by Riggs in 1941 made it possible to record the ERG in human beings without discomfort. The present contact lens is a modification of the original (Fig. 1 C ), which, as used with human beings, was equipped with an electrode ( E ) identical to that shown in Figure 1. This electrode consists of a silver disc cemented into a hole in the contact

Sir-I was very interested to read the report of Dr. G.A. Carons case (16 April p. 980). I have not seen any instances of corneal oedema in association with contact lenses due to oestrogen therapy. I have however seen corneal oedema supervening in a case successfully fitted with scleral lenses during the patients pregnancy. The case followed much the same course as Dr. Carons: the oedema disappeared after the contact lens was discontinued. The cornea partakes of water retention due to electrolyte imbalance in the rest of the body especially if its mechanism of dehydration and homoeostasis is stretched as happens with the wearing of a contact lens. The electrolyte imbalance could be local of general nervous of hormonic etc. I gave instances of local electrolyte imbalance causing corneal oedema in the papers entitled "Some Observation on the Physiology of the Cornea" and "Factors in the Genesis of Corneal Oedema."-I am etc.(FULL TEXT)

The present paper describes in detail a new method developed for d.c. registration of the human ERG. In this way it was possible to investigate retinal functions that have not earlier been studied clinically, e.g. the retinal responses below the b-wave threshold, the c-wave and other slow potentials after cessation of the light stimulus. It is suggested that the method might lead to an earlier diagnosis than before of certain retinal and pigment epithelial disorders induced by drugs or based on other pathological conditions.