ページの画像
PDF
ePub

ments did not give him any pain; and they were made in the pre-, sence of his mother, and of Mr. Woodford, a clerk in his majesty's treasury. I held the objects at different distances from his eye, and inquired very particularly if he was sensible of any difference in their situation; which he always said he was, informing me, on every change, whether they were brought nearer to, or carried further from him. I again inquired, both of his mother and himself, whether he had ever, before this time, distinguished by sight any sort of object; and I was assured by both that he never had, on any occasion; and that, when he wished to discover colours, which he could only do when they were very strong, he had always been obliged to hold the coloured object close to his eye, and a little on one side, to avoid the projection of the nose. No further experiments were made on that day. On the 1st of January, 1 found that his eye continued quite free both from pain and inflamination, and that he felt no uneasiness on the approach of light. I showed him a table knife; which at first

he called a spoon, but Soon rectified the mistake, giving it the right name, and distinguishing the blade from the handle, by pointing to each as he was desired. He afterwards called a yellow pocket-book by its name, taking notice of the silver lock in the cover. I held my hand before him; which he knew, but could not at first tell the number of my fingers, nor distin guish one of them from another. I then held up his own hand, and desired him to remark the diffe rence between his thumb and fingers; after which, he readily pointed out the distinctions in mine also. Dark-coloured and smooth

objects were more agreeable to hin than those which were bright, and rough. On the 3d of January, he saw, from the drawing-room window, a dancing bear in the street; and distinguished a number of boys that were standing round him, noticing particularly a bundle of clothes which one of them had on his head. On the same evening, I placed him before a looking-glass, and held up his hand: after a little time he smiled, and said he saw the shadow of his hand, as well as that of his head.

He could not then

distinguish his features; but, on the following day, his mother having again placed him before the glass, he pointed to his eyes, nose, and mouth, and seemed much gratified with the sight.

"Having thus stated the principal observations that were made by master W. I shall now make a brief comparison between this statement which is given in the XXXVth volume of the Philoso phical Transactions of Mr. Cheselden's patient, who was supposed to be born blind, and obtained his sight when he was between thirteen and fourteen years old.

"It should be observed, that, though master W. was six years younger than Mr. Cheselden's patient, he was remarkably intelligent, and gave the most direct and satisfactory answers to every question that was put to him, Both of them, also, if not horn blind, lost their sight so very early, that, as Mr. Cheselden expresses it, they had not any recollection of having ever seen.'

[ocr errors]
[ocr errors]

"My first remark is, that, contrary to the experience of Mr. Cheselden's patient, who is stated to have been so far from making any judgment of distance, that he thought all objects touched his

[ocr errors]

' eyes,

[ocr errors]
[ocr errors]

kind could occur; since, in addition to the declaration of himself and his mother, it was proved by the testimony of the surgeon who examined his eyes in the country, that the cataracts were fully formed before he was a year old. And I beg leave to add further, that on making inquiries of two children between seven and eight years of age, now under my care, both of whom have been blind from birth, and on whom no operation has yet been performed, I find that the knowledge they have of colours, limited as it is, is sufficient to enable them to tell whether coloured objects be brought nearer to, or carried further from them; for instance, whether they are at the distance of two inches or four inches from their eyes; nor have either of them the slightest suspicion, as is related of Mr. Cheselden's patient, that coloured objects, when held before them, touch their eyes.

eyes, as what he felt did his skin,' master W. distinguished, as soon as he was able to see, a table, a yard and a half from him; and proved that he had some accuracy in his idea of distance, by saying, that it was a little further off than his hand could reach.This observation, so contrary to the account we have received of Mr. Cheselden's patient, would have surprised me much more than it did, if I had not previously, in some similar instances, had reason to suspect that children, from whom cataracts had been extracted, had a notion of distance the first moment they were enabled to see. In the instance particularly of a young gentleman from Ireland, fourteen years old, from each of whose eyes I extracted a cataract, in the year 1794, in the presence of Dr. Hamilton, physician to the London Hospital, and who, before the operation, assured me, as did his friends, that he never had seen the figure of any object, Dr. Hamilton and myself were much astonished by the facility with which, on the first experiment, he took hold of my hand at different distances, mentioning whether it was brought nearer to, or carried further from him, and conveying his handferent in shape and magnitude;' to mine in a circular direction, that for master W. knew and described we might be the better satisfied of a letter, not only as white, but the accuracy with which he did it. also as square, because it had corIn this case, however, and in others ners; and an oval silver box, not of a like nature, although the pa- only as shining, but also as round, tients had certainly been blind from because it had not corners: he likeearly infancy, I could not satisfy wise knew, and called by its name, myself that they had not, before a white stone mug, on the first day this period, enjoyed a sufficient de- he obtained his sight, distinguishgree of sight to impress the image ing it from a bason, because it had of visible objects on their minds, à handle. These experiments were and to give them ideas which could made in the presence of two renot afterwards be entirely oblite- spectable persons, as well as myself; rated. In the instance of master and they were several times reW. however, no suspicion of this peated, to convince us that we

"But the judgment which ma. ster W. formed of the different distances of objects, was not the only instance in which he differed from Mr. Cheselden's patient; who, we are informed, did not know the figure of any thing, nor any one thing from another, however dif

[ocr errors]

could

[ocr errors]

could not be mistaken in them. I mention the circumstance, however, with much diffidence, being aware that the observations not only differ from those that are related of Mr. Cheselden's patient, but appear, on the first statement, to oppose a principle in optics, which I believe is commonly and justly admitted, that the senses of sight and feeling have no other connection than that which is formed by experience; and, therefore, that the ideas derived from feeling can have no power to direct the judgment, with respect either to the distance or form of visible objects. It should be recollected, however, that persons who have cataracts in their eyes, are not, in strictness of speech, blind, though they are deprived of all useful sight. The instances I have adduced prove, that the knowledge they have of colours is sufficient to give them some idea of distance, even in their darkest state. When, therefore, their sight is cleared by the removal of the opaque crystalline, which intercepted the light, and the colour of objects is thereby made to appear stronger, will it be difficult or unphilosophical, to conceive that their ideas of distance will be strengthened, and so far extended as to give them a knowledge, even of the outline and figure of those objects with the colour of which they were previously acquainted?

"The case which I have here related appears to deserve notice, not only on account of the observations that were made by the patient on recovering his sight, but also on account of the hint which it affords to surgeons, relative both to the mode in which the cataract may best be removed, when children are born with this disorder,

1801.

and the time when it is most proper to perform the operation.

"The Baron de Wenzel, in his ingenious Treatise on the Cataract, with great force of reasoning, deduced from the long and successful experience of his father and himself, recommends, in all cases of this disorder, without making any exceptions, the operation of extraction, in preference to that of depression; and I believe it is now generally acknowledged by medical men, that, in the more common cases, his decision, as to the mode of operating, is perfectly well founded. The Baron admits that the operation is not so certain a cure in children as it is in persons of a more advanced age; both on account of their untractableness, and because, in them, the opacity of the crystalline is not unfrequently accompanied with an opacity in the capsule that contains it. On these accounts, when children are born with this disorder, he advises to postpone the operation, until they are old enough to be made sensible of the loss they sustain by the want of sight, and have firmness of mind to submit patiently to the means that are requisite in order to obtain it. Influenced by this opinion of the Baron, and believing the operation of extraction to be so much superior to that of depression, that the latter ought not, on any occasion, to have the preference, I have given advice, in the cases of a considerable number of children who were born with this disorder, to postpone every attempt to relieve them, until they were thirteen or fourteen years old. Prior to this time, it did not appear to me that children could be depended upon to submit, with due steadiness, to the repeated introduction of instruments, which is sometimes

L

sometimes necessary in extracting the cataract; and, even at this age, the eyes of some are so small, and in such a constant rolling motion, that it is almost impossible properly to accomplish the operation. The Portuguese lad, whose case has been related, afforded an instance of this kind; and I consider it as a fortunate circumstance that it came under my notice, since, in some degree, it may be said to have obliged me to examine, more attentively than I had before done, the advantages and disadvantages of the operation of depression; which operation, being more easy to perform than that of extraction, has certainly this advantage in the cases of children, (to which alone I here advert,) that it may be performed with equal safety when they are only seven years of age, as it may at any subsequent period of their lives.

"It is well known that the late Mr. Pott, who published his remarks on the cataract in the year 1775, was a strenuous advocate for this operation; and, though he appears to me to have much underrated the advantages of extraction, it must be allowed that he makes many just and highly pertinent observations on the use of the couching needle, in those cases where the cataract is soft, or fluid. Mr.

Pott considered this as a very common state of the disorder; and does not make any distinction between the cataract when it attacks grown persons, and when children are born with it. In the former case, experience inclines me to believe, that the cataract is very rarely fluid, or even soft; whereas, in the latter, I have always found it, agreeable to the observation of the Baron de Wenzel, in one or other of these states. Although,

therefore, in the case of grown persons, the operation of extraction appears to me to have very great advantages over that of depression, yet, in the case of children, I can readily accede to almost the whole that Mr. Pott advances in favour of depression. If the couching needle be passed in the way in which it is usually introduced to depress the cataract, and thereby a large aperture be made in the capsule of the crystalline, (which operation may be performed with perfect safety, and with very little pain to the patient, whilst the eye is fixed with a speculum oculi,) the opaque crystalline, being thus brought into contact with the aqueous and vitreous humours, will, in a shorter or longer space of time, according to its degree of softness, be absorbed; and, if there be not an opacity in the capsule, as well as in the crystalline, the pupil will become clear, and the patient will acquire a very useful sight. If, in addition to the opacity of the crystalline, the capsule be also opaque, and, in consequence of this, the operation do not prove successful, the eye will nevertheless be perfectly uninjured, and it will be as fit, at a subsequent period, to have the capsule extracted, as it would have been if no attempt of the above kind had been previously made.

"From the foregoing observations, I flatter myself I shall be justified in deducing the following inferences :

"First, When children are born blind, in consequence of having cataracts in their eyes, they are never so totally deprived of sight as not to be able to distinguish colours; and, though they cannot see the figure of an object, nor even its colour, unless it be placed

within a very short distance, they nevertheless can tell whether, when within this distance, it be brought nearer to, or carried farther from them.

"Secondly, In consequence of this power, whilst in a state of comparative blindness, children who have their cataracts removed, are enabled, immediately on the acquisition of sight, to form some judgment of the distance, and even of the outline, of those strongly defined objects with the colour of which they were previously acquainted.

"Thirdly, When children have been born with cataracts, the crystalline humour has generally, if not always, been found either in a soft or fluid state. If, therefore, it be not accompanied with an opacity, either in the anterior or posterior portion of the capsule, and this capsule be largely punctured with the couching needle, introduced in the way in which this instrument is usually employed to depress the cataract, there is reason to expect that the opaque matter will, sooner

or later, be absorbed, the pupil become clear, and the sight be re stored.

"Fourthly, If, in addition to the opacity of the crystalline humour, its capsule be also opaque, either in its anterior or posterior portion, or in both, (which circumstance cannot be ascertained before the operation,) and, in consequence of this, the operation above mentioned should not prove successful, it will not preclude the performance of extraction afterwards, if this be thought adviseable.

"Fifthly, The operation above mentioned being much more easy to perform than that of extraction, and it being possible to fix the eye with perfect safety during its performance, by means of a speculum oculi, it may be undertaken at a much earlier age than the latter operation; and a chance may of course be given to the patient, of receiving instruction, without that loss of time which has usually been thought unavoidable, when children are born with this disorder*.

"It ought to be mentioned, that about a month after the abovementioned operation on Master W.'s left eye, I performed a similar operation on the right eye of the same young gentleman. Although he behaved with great firmness on the first occasion, it was not without considerable difficulty that his head was kept steady on the second. The operation, however, gave him very little pain, and no inflammation followed; but the opacity afterwards was not diminished; and he did not acquire any additional sight from this eye. There was an evident mark in that part of the capsule where the couching needle pierced it; though the aperture was too small to admit a sufficient number of rays of light to give an idea of objects. It seems probable that the want of success, in this instance, was owing to an opacity in the capsule, which was incapable of being absorbed. The eye, however, is as fit to have the aperture in the capsule enlarged, or a portion of it removed, when the patient is of a proper age, as if no operation had been previously performed.

"I beg leave also to add, that since these pages were put together, a case has come under my care, which seeins to afford a confirmation of the remarks that have been offered respecting the state of the cataract in children, and the effects that are likely to be produced by the operation of puncturing the capsule that contains it. A young lady, eighteen years old, was put under my care, who had been blind from an early part of her infancy. She had a cataract completely forined in both eyes; and in each there were three or four opaque spots, more white than the rest, which seemed to lie on the surface of the opaque crystalline. I punctured the capsule of each with a couching needle, according to the proposition in the preceding pages, in the presence of Mr. Scott, surgeon, in St. Alban's-street. The operation gave her no pair: audi L2

« 前へ次へ »