Developmental deformities of the crystalline lens / by E. Treacher Collins.

  • Collins, E. Treacher (Edward Treacher), 1862-1937.
Date:
[1908]
Catalogue details

Licence: In copyright

Credit: Developmental deformities of the crystalline lens / by E. Treacher Collins. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    stud. Presumably in such cases the apposition of the ends of the lens fibres which have grown forwards from the sides has not been completely effected, some granular material having remained interposed in the line of suture. Taking it now that the evidence brought forward suffices to show that the lens capsule is the product of the epithelial cells lining it, it is obvious that the posterior part of the capsule has only a very short time in which it can be formed, for the cells which compose the posterior layer of the lens vesicle soon lengthen out into lens fibres, and then become separated from the lens capsule by the growth around them of the new lens fibres laid on laterally ; the posterior capsule for the remainder of life being devoid of any cellular lining. Under these circumstances it is not surprising that defects in the develop- ment of the central part of the posterior capsule should occasionally be met with, causing it to be unduly thin or absent altogether. Several cases have now been recorded in which a congenital gap in the posterior capsule of the lens has been found. The first of the sort, so far as I am aware, was in a specimen which I described and pictured in 1892.* It was the right eye of a child, 9 months old, in which a peculiar appearance had been first noticed when 3 weeks old. This was found on examination to be due to a grey reflex at the posterior part of the lens with a large hoemorrhage on its surface. It suggested the appearance of a gliomatous growth, and the eye was consequently excised. Pathological examination showed that there was no new growth, but an opacity at the posterior part of an otherwise clear lens with a reddish stain on its surface. No remains of any central artery of the vitreous was to be seen. In microscopical sections of the eye passing through the pupil, the anterior capsule of the lens appears normal, it is lined by a single layer of cells which terminate as usual in the nucleated zone. On tracing the capsule backwards from the nucleated zone it is seen as a normal capsule for some distance ; then at the posterior pole it is for some distance entirely absent. In the gap where it is absent, and for a short distance m front and behind the capsule on each side of it, there is a mass of tissue composed of elongated nucleated cells and fibres. This tissue forms the anterior part of the vitreous with which it is continuous. It resembles what Hess has described as atypically developed vitreous, i.e., mesoblast which should have developed •into vitreous humour, but which has formed a fibro-cellular ti.ssue in place of the usual vitreous structure. When this takes place some of the blood-vessels of the foetal vitreous usually persist. In this specimen no blood vessels are seen in the mass of tissue at the back of the lens, but there are collections of red Dlood^corpuscles in the posterior part of the lens immediately Royal r.on,i. 0/^fi/fial. IIosp. Reports, Vol. XIII. p. 363.