G W Crock

Diabetic retinopathy in pregnancy: a 12-year prospective survey.

A prospective study extending over 12 years has surveyed 107 latent diabetics and 172 clinical diabetics during pregnancy. Among the clinical diabetics background retinopathy was evident or developed during pregnancy in 40 cases. Eleven cases showed proliferative changes, only 1 such case appearing de novo during gestation. There was a higher incidence of fetal loss in the diabetic than the latent diabetic group, and this loss was highest in those with proliferative retinal disease. Pregnancy was to associated with any increased risk to the mother of progression of retinal changes and visual loss. The only known direct relationship, namely, that between duration of diabetes and ocular complications, is confirmed.

FLUORESCEIN ANGIOGRAPHY OF NORMAL AND ATROPHIC OPTIC DISCS

Abstract Fluorescein angiography was performed on Summary fifty patients with normal optic discs, ten with unequivocal optic atrophy, three with chronic papillœdema and segmental optic atrophy, and one with toxic amblyopia. The normal disc angiogram consists of three components, one of which is consistently absent in cases of optic atrophy.

A scanning electron microscopic examination of retinoblastoma in tissue culture.

Tissue cultures were established from 6 retinoblastomas and the cultured cells examined by scanning electron microscopy. Cells from cultures of normal fetal retinal and glial tissue were also examined by SEM. Though a number of different cell types were found to coexist in the retinoblastoma cultures, most had the features of cells of either glial or neuronal origin. Evidence of further differentiation of cells in each series was seen. These findings indicate that the cell of origin in retinoblastoma is a multipotential stem cell which, though neoplastic, is still capable of differentiation into both glial and neuronal series.

Intraocular diathermy coagulation

Previously used transvitreal diathermy systems were found to be less than adequate. A new, safer 1.25 MHz medium frequency bipolar instrument is presented, which obviates most of the earlier drawbacks. Coagulation at the retinal surface can be obtained with as little as 0.15 J.

A new system of microsurgery for human and experimental corneal graftin. I. The contact lens corneal cutter, stereotaxic eye holder, donor disc chuck, and frame.

A new microsurgical system is presented for human and experimental corneal grafting. The system is based on novel methods of corneal cutting and holding which simplify collection procedures and minimise operator manipulation during transplantation.

The COMMIDO. Combined Operation Magnifiers and Miniature Indirect Ophthalmoscope.

A miniature binocular indirect ophthalmoscope is described, incorporating magnification. It is an improved version of the simple instrument reported by Crock, Galbraith, and Parel (1969). Although the problem ofcombining magnification with binocular indirect ophthalmoscopy was then considered, an entirely satisfactory technical solution was not achieved. That solution has now been found and the resulting instrument (Fig. i) has withstood clinical testing over the past 2 years. Additional design features include a new light-source and an improved battery pack, providing greatly increased illumination. Ruckers excellent historical account of the ophthalmoscope does not mention the optical combinations described here (Rucker, I972).

Instrumentation and Techniques for Corneal Microsurgery

We developed two additions to a new system of microsurgery for corneal cutting and grafting: a 10-mm contact lens corneal cutter and a stereotaxic donor disk chuck and frame.

Extraction of Soemmerring's ring. Before retinal surgery in aphakic detachment.

Norton (i 964) showed that retinal detachment in aphakia has a more favourable prognosis than previous workers had suggested (Schepens, 1951; Hughes, 1952; Colyear and Pischel, 1956). A small group of cases remains in which the outcome of retinal surgery is prejudiced by dense lens remnants. The major factors contributing to failure in such cases are inadequate fundus view and vitreous retraction. This paper reports experience of preliminary anterior segment surgery to clear the ocular media in five unfavourable cases of aphakic retinal detachment. The operating microscope has made this type of surgery feasible, safe and highly effective.

Fascia lata rack for retinal detachment surgery.

The use of biological polymers for external plombage in retinal detachment surgery is well established (Havener and Wachtel, I964; Kloti, I964; Crock and Galbraith, I966). Fascia lata is the tissue most widely employed because it is readily obtainable and is easily sterilized and stored (Havener and Olson, I962). When tightly twisted it makes an ideal encircling element for scleral buckling. This paper describes an instrument which facilitates the production of firm uniform cords from strips of fascia lata.