Fig. 24 (No. 45).—Right eye, lower half.
Fig. 25 (No. 116).—Right eye, nasal half.
Fig. 26 (No. 306).—Left eye, upper half.
Fig. 27 (No. 306).—Microscopic section, low power.
In No. 116 it is the retina which is impacted in the corneal wound (Pl. IV., Fig. [25]). It seems likely that in this instance the sequence of events was as follows: A severe plastic inflammation resulted from the couching, and involved among other structures a capsular synechia, which had formed at the time of operation or soon after. The vitreous became heavily infected, and the consequent exudate became adherent on the one hand to the retina, which thereby underwent total detachment, and on the other to the capsule and its synechia. The progressive contraction of the scar-tissue then drew the retina into the wound. This would appear to be the most likely explanation, but it is not impossible, in dealing with such an operation as couching, that the retinal detachment was very extensive, and that the injury inflicted provided a path along which a direct prolapse of the retina may have occurred.
The Sclera.—A very large number of Indian cataract couchers perform the posterior operation, and therefore make their preliminary incision in the sclera outside the limbus. Dr. Ekambaram, who has watched these men at work, believes that they deliberately endeavour to avoid the ciliary body, and it also looks as if some of them purposely place their incision below the external rectus muscle. Like his Western confrère, the Indian surgeon does not always succeed in placing his incision just where he wishes to; this is not surprising, as many of these men work without any local anæsthetic, and not a few of their patients are nervous and unruly to the last degree. Moreover, it is more than probable that there are different opinions amongst couchers as to the best site for the preliminary cut. These considerations will serve to explain the variety of location of the scars, as found in the specimens before us; indeed, some such explanation is called for, since the cicatrices may be found as far forward as the limbus, and as far back as the equator of the globe; what is more, they may be seen in the present collection, not only in their common situation, on or near the horizontal meridian, but in any of the quadrants of the eye.
As a rule, the evidence of injury to the sclera is to be inferred from the interference with the parts beneath that coat, and such instances will be taken up when we come to consider the lesions of the ciliary body and choroid; but occasionally we have been fortunate enough to hit off the scleral scar either in the original division of the globe or during the course of sectioning of part of it for the purpose of microscopic examination.