46 Scientific Proceedings, Royal Dublin Society. 
received but scant attention, owing, doubtless, to the discovery of 
the ophthalmoscope; and, in recent years, entoptic diagnosis of the 
eye has been almost completely overlooked, even by ophthalmo- 
logists.* 
It is, therefore, not surprising that, in common with many 
others, I was wholly unaware of the foregoing investigations 
when my attention was called to entoptic observation by a curious 
discovery of a defect in my own vision which I noticed some 
twelve months ago. Looking at a bright sky through a pin- 
hole in a piece of card held close to the right eye, I was surprised 
to find the dise of light on the retina obscured by a dark shadow 
of fixed and definite shape, resembling the letter L reversed (4). 
The left eye also presented a shadow when the pin-hole was 
placed before it, only in this case it was a fainter and straight 
horizontal bar half way across the disc. Using a very fine needle- 
hole in a thin sheet of metal, held close to the eye before a good 
light, the obscurities were seen in great detail, revealing the struc- 
ture of some partially opaque tissues in the body of eacheye. Fig. 1 
shows a rough sketch of these obscurities made at an early stage. 
Lert. Rieut. 
Fie. 1. 
Upon consulting the eminent Dublin oculists, Dr. Arthur 
Benson and Dr. C. Fitzgerald, Surgeon Oculist to the King, the 
unpleasant fact was revealed that there was incipient cataract in 
each eye, more developed in the right than the left, and to this 
cause the shadows which I saw were presumably due. Dr. Fitz- 
gerald carefully drew the shape of the opacity that he had 
observed, by means of the ophthalmoscope, in each eye. These 
1 Since this paper was read, Dr. Ettles, of London, has drawn my attention to a 
paper on entoptic vision by Dr. Darier, entitled ‘‘ De la possibilité de voir son propre 
erystallin.’’ Annales d’ Oculistigque, vol. cxiv., September, 1895, p. 198. 
