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A Contribution to the Study of the Diseases of The Eye in the Dog
GENERAL ARTICLES.
31
A CONTRIBUTION TO THE STUDY OF THE DISEASES OF THE EYE IN THE DOG.
By GEOFFREY H. LIVESEY, M.R.C.V.S., Hove, Sussex. FOR the last few years I have been making a point of looking into the eyes of every dog that has corne under my notice, and in many instances making a careful examination of them with the ophthalmoscope if necessary. After seeing several thousands I have been very much struck with the frequency with which one meets the so-called" Senile Cataract," especially in medium-aged dogs, in which senile changes should not yet have commenced. Next to cataract I have most frequently seen glaucoma, and less often pigmentary retinitis. It is with these three conditions that I wish to deal more particularly. Glaucoma is far more common than is generally supposed. By this term I mean a pathological condition of the eye in which there is increased tension of the ocular globe from increased pressure of the fluids within it. Originally the name was used (as the word signifies) for the peculiar bottle-green colour sometimes seen in the eye in this condition. But this is by no means always to be seen. It is rarely seen in man, and in only about one case in twenty-five have I seen it in the dog. When it is present, it is remarkable at once and can scarcely be overlooked. Ordinary glaucoma is, however, generally overlooked, and it is only by careful examination that its presence is detected. The disease affects one or both eyes and tenc;ls to run a chronic course, producing permanent changes in the eye and eventual blindness. The remote causes of the condition seem rather obscure in the dog, but the direct cause is always the partial obstruction of the filtration area and consequent prevention of transudation of fluids into the Canal of Schlemm. Increased bulk of the lens or any other such cause as would tend to push the iris forward would produce more or less closure of the angle in which this filtration area is situated. Such a condition naturally tends to increase, and with it the internal tension of the eye. Sometimes cases have been brought to me because of a slight opacity of the cornea, which is often present in the early stages of glaucoma in the dog. This opacity is almost always in the deeper layers of the cornea, and must not be confused with the opacity resulting from conjunctivitis. It is nebular or slightly striated and generally situated centraIly, and no doubt arises from the mechanical interference with nutrition. This condition is worth examining and becoming acquainted with, as the usual atropine lotions (so commonly supposed to be the panacea for all eye troubles) are here inadmissible. The dilatation of the pupil would only cause greater obstruction to transudation, and the condition of the patient would only be aggravated. In many cases, however, this opacity of the cornea may be totally absent, and the eye appear quite clear and bright. The dog if carefuIly watched , may occasionally show pain by passing his forepaws over his eyes and nose, or rubbing his eye on the carpet or on his bed. There is often photophobia, and the eyes in the early stages
32
GENERAL ARTICLES.
are more sensitive to changes of temperature. The only way to test the amount of extra tension present is by palpation, but this requires a great deal of practice before it conveys much to the average touch. The eye should be gently passed back into the orbit with one finger (the lids being, of course, closed), and the hardness or elasticity of the globe tested with another finger. When the condition is more or less acute from inflammatory changes taking place in the eye, it is easily noticed. The eyeballs, may appear larger, the cornea sometimes seems more convex and may or may not be cloudy', the pupil is dilated, and the iris is pressed forward and may be almost touching the cornea. The pupil may appear brilliantly green, and there is always a marked degree of blindness. In both the acute form and the more slowly progressing the pupil is always more dilated than normal and more or less irresponsive tobright l!ght. A healthy pupil in a young dog should contract under
_ _ __ _ Scl ... olic. Cool' _c .... 1 0 5"',' ...,," \~~!f-oIiIiiN9/___- - - - ' C oI"HY f\.ouu 'P1~_ _ _ _ C
r
on III nc.li ca OTn
0.
rf-~fI-- kqu4!ou~ humouy
Diagram of eye in glaucoma.
the influence of bright light almost to the size of a pin point, but in these cases it contracts slowly and to a far less extent. Using the· ophthalmoscope, one almost invariably sees some change in the retina" the most common being pulsation of the veins, and fibrous patches over the surface and especially in the neighbourhood of the disc, with atrophy from pressure. The above symptoms are entirely consequent upon and invariably followed by increased ocular tension. In the first place there is interference with the circulation and engorgement of the veins, and in the second place symptoms arising from pressure on the nerves. Filaments of the fifth nerve atrophy, causing eventually diminished sensibility on the surface of the eye. The function of the third nerve is interfered with, and the ciliary body and processes are affected. The lens is relaxed, and from its normal position bulges forwards towards the anterior chamber, thereby increasing the already high tension, as has been described above. The sphincter pupillce is also relaxed"
GENERAL ARTICLES.
33
causing wide dilatation, and hastening the course of the disease. The retinitis is consequent on the pressure, and is best s.een where the nerve enters the eye. Here the disc is depressed and cup like. This condition is bes't seen in the ai:ute stage. Glaucoma defies all medicinal treatment, though eserine is of distinct value as a palliative. I f taken in hand early, the disease may be at once arrested and the sight more Qr less preserved by the simple operation of sclerotomy, which unless carelessly performed is quite without danger or bad after effects. The so-called senile cataract I believe to be one of the results of long standing glaucoma in a large number of cases, even though the glaucoma is only slight in degree. The lens consists of a hard nuclear portion, and a softer external portion named the cortex, which is surrounded by endothelium lining the capsule. In the substance of the lens exist minute stellate clefts. Nutrition (the lens being nonvascular) is by transudation of fluids from surrounding tissues. It is not yet clearly known how waste products are excreted, but probably they are driven inwards towards the centre. The lens increases slowly in size during life by the superimposition of new fibres derived from the anterior endothelium. Any pathological change in the eye affecting the circulation must necessarily affect the lens. . In old age nutritive changes are always seen. In the young adult, however, such changes are so frequently to be seen that I have searched for some cause which may be reasonably held to be responsible. I think this is to be found in glaucoma. In the case of glaucoma the circulation is interfered with to a great extent, and the functions of nutrition and excretion are much depressed. In the first place there is diminution of the quantity;of nourishment. This is brought about by wasting of the ciliary body consequent upon the compression of the filaments of the third nerve and trophic changes due to pressure on other nerves, and by the obstruction to the inflow of blood to all the internal parts of the eye. The quaNty of the nutrient media is lessened, owing to the inflammatory changes existing and the non elimin.ation of waste products, Malnutrition, of course, directly affects the lens itself. The nuclear portion becomes smaller, and there is a certain amount of shrinking of the lens fibres. The stellate clefts are enlarged, and small vacuoles may be found. The cortical portion may be separated from the nuclear, the interspace being filled with fluid causing more or less opacity; or the endothelium may atrophy and become slightly opalescent. In some cases of glaucoma one may see perfect examples of Morgagnian cataract, where the cortex of the lens has undergone liquefaction and the nuclear portion may be made to oscillate visibly in the capsule. This has been mistaken for true displacement ~f the lens. (Vide case below.) Of the remote causes of glaucoma those which seem to me to be the most important are: (a) Heredity; (b) Inbreeding; (c) Distemper. Of these I only wish t6 refer to (b) Inbreeding. Those breeds of dogs which have for generations been inbred for fancy or show purposes seem particularly susceptible to eye troubles, and especially to glaucoma. The result of the glaucoma in these cases· is early seen in the retina, which rapidly commences to undergo pigmentary degeneration. Pigmentary retinitis is seen in human beings as a result of marriages c
GENERAL ARTICLES.
34
of consanguinity, and often affects several members of one family. The same remark applies to dogs, the disease running a protracted course and being quite intractable. The appearance of the retina is easily recognised with the aid of the ophthalmoscope. The pigment is laid down irregularly, and appears as black blotches on the surface of the retina; it seems to follow the course of the vessels, and sometimes to obliterate them. The patient nearly always shows marked photophobia in the earlier stages, and there is evidently a certain amount of pain. Glaucoma is always present, and very frequently the cornea shows some opacity. The condition, though incurable, may perhaps be arrested by sclerotomy and the frequent use of eserine. To sum up the result of my observations-glaucoma is far more common in dogs than has been hitherto supposed. Unless checked early by operation it causes dimness of the lens, and in inbred dogs frequently gives rise to pigmentary retinitis. I quote one typical case (from notes made at the time) showing all three conditions to a marked degree. 22nd Dec. 1903.-Brindle skye terrier with black points, three and a half years old, suffering from glaucoma and keratitis in the right eye, complete blindness, and apparent dislocation of the lens in the left. On the 29th, after treatment with lotions, the cloudiness in the right eye was less marked, but still only an imperfect view could be obtained of the interior of the eye. The dog is totally blind in the left eye, and has only partial vision in the right. He can see nothing directly in front of him, and has only a very imperfect vision of objects to the right of him. He guides himself entirely by the senses of sound and smell. On 9th January 1904, the eyes were very carefully examined with the aid of the ophthalmoscope. The left eye shows apparently complete dislocation of the lens, which is practically floating, and can be made to oscillate by gently swaying the dog's head. l The dog is totally blind in this eye. The right eye shows well developed gla,ucoma, the iris being pressed forward almost against the cornea. The lens is displaced upwards and outwards, and shows partial cataract (stellate). Pigmentary retinitis is present in both eyes, and is similar to the pigmentary retinitis of human beings. This patient is very much inbred (his dam having been mated with her sire), and comes of an already inbred variety. As a puppy he had enjoyed very good health and apparently good sight, and at the present day he is a strong healthy dog, with a good coat, good bone, and straight joints, and in no sense" weedy." The glaucoma no doubt troubles him, and he suffers some discomfort from it making him very depressed. He is highly nervous, and his senses of smell and hearing are very acute-no doubt compensatory. The keratitis is consequent on the glaucoma. I can only account for the displacement of the lens in the right eye by interference with the function of the third nerve. The prognosis in this case is not hopeful, the sight being almost certain to be entirely lost. Treatment consists of soothing and astringent lotions when there is evident pain, and 6!O gr. eserine night and morning to relieve ocular tension. If no benefit is derived from this treatment I intend to perform sclerotomy. 1
This was evidently an error of diagnosis.
The condition was Morgagnian cata,ract.
31
A CONTRIBUTION TO THE STUDY OF THE DISEASES OF THE EYE IN THE DOG.
By GEOFFREY H. LIVESEY, M.R.C.V.S., Hove, Sussex. FOR the last few years I have been making a point of looking into the eyes of every dog that has corne under my notice, and in many instances making a careful examination of them with the ophthalmoscope if necessary. After seeing several thousands I have been very much struck with the frequency with which one meets the so-called" Senile Cataract," especially in medium-aged dogs, in which senile changes should not yet have commenced. Next to cataract I have most frequently seen glaucoma, and less often pigmentary retinitis. It is with these three conditions that I wish to deal more particularly. Glaucoma is far more common than is generally supposed. By this term I mean a pathological condition of the eye in which there is increased tension of the ocular globe from increased pressure of the fluids within it. Originally the name was used (as the word signifies) for the peculiar bottle-green colour sometimes seen in the eye in this condition. But this is by no means always to be seen. It is rarely seen in man, and in only about one case in twenty-five have I seen it in the dog. When it is present, it is remarkable at once and can scarcely be overlooked. Ordinary glaucoma is, however, generally overlooked, and it is only by careful examination that its presence is detected. The disease affects one or both eyes and tenc;ls to run a chronic course, producing permanent changes in the eye and eventual blindness. The remote causes of the condition seem rather obscure in the dog, but the direct cause is always the partial obstruction of the filtration area and consequent prevention of transudation of fluids into the Canal of Schlemm. Increased bulk of the lens or any other such cause as would tend to push the iris forward would produce more or less closure of the angle in which this filtration area is situated. Such a condition naturally tends to increase, and with it the internal tension of the eye. Sometimes cases have been brought to me because of a slight opacity of the cornea, which is often present in the early stages of glaucoma in the dog. This opacity is almost always in the deeper layers of the cornea, and must not be confused with the opacity resulting from conjunctivitis. It is nebular or slightly striated and generally situated centraIly, and no doubt arises from the mechanical interference with nutrition. This condition is worth examining and becoming acquainted with, as the usual atropine lotions (so commonly supposed to be the panacea for all eye troubles) are here inadmissible. The dilatation of the pupil would only cause greater obstruction to transudation, and the condition of the patient would only be aggravated. In many cases, however, this opacity of the cornea may be totally absent, and the eye appear quite clear and bright. The dog if carefuIly watched , may occasionally show pain by passing his forepaws over his eyes and nose, or rubbing his eye on the carpet or on his bed. There is often photophobia, and the eyes in the early stages
32
GENERAL ARTICLES.
are more sensitive to changes of temperature. The only way to test the amount of extra tension present is by palpation, but this requires a great deal of practice before it conveys much to the average touch. The eye should be gently passed back into the orbit with one finger (the lids being, of course, closed), and the hardness or elasticity of the globe tested with another finger. When the condition is more or less acute from inflammatory changes taking place in the eye, it is easily noticed. The eyeballs, may appear larger, the cornea sometimes seems more convex and may or may not be cloudy', the pupil is dilated, and the iris is pressed forward and may be almost touching the cornea. The pupil may appear brilliantly green, and there is always a marked degree of blindness. In both the acute form and the more slowly progressing the pupil is always more dilated than normal and more or less irresponsive tobright l!ght. A healthy pupil in a young dog should contract under
_ _ __ _ Scl ... olic. Cool' _c .... 1 0 5"',' ...,," \~~!f-oIiIiiN9/___- - - - ' C oI"HY f\.ouu 'P1~_ _ _ _ C
r
on III nc.li ca OTn
0.
rf-~fI-- kqu4!ou~ humouy
Diagram of eye in glaucoma.
the influence of bright light almost to the size of a pin point, but in these cases it contracts slowly and to a far less extent. Using the· ophthalmoscope, one almost invariably sees some change in the retina" the most common being pulsation of the veins, and fibrous patches over the surface and especially in the neighbourhood of the disc, with atrophy from pressure. The above symptoms are entirely consequent upon and invariably followed by increased ocular tension. In the first place there is interference with the circulation and engorgement of the veins, and in the second place symptoms arising from pressure on the nerves. Filaments of the fifth nerve atrophy, causing eventually diminished sensibility on the surface of the eye. The function of the third nerve is interfered with, and the ciliary body and processes are affected. The lens is relaxed, and from its normal position bulges forwards towards the anterior chamber, thereby increasing the already high tension, as has been described above. The sphincter pupillce is also relaxed"
GENERAL ARTICLES.
33
causing wide dilatation, and hastening the course of the disease. The retinitis is consequent on the pressure, and is best s.een where the nerve enters the eye. Here the disc is depressed and cup like. This condition is bes't seen in the ai:ute stage. Glaucoma defies all medicinal treatment, though eserine is of distinct value as a palliative. I f taken in hand early, the disease may be at once arrested and the sight more Qr less preserved by the simple operation of sclerotomy, which unless carelessly performed is quite without danger or bad after effects. The so-called senile cataract I believe to be one of the results of long standing glaucoma in a large number of cases, even though the glaucoma is only slight in degree. The lens consists of a hard nuclear portion, and a softer external portion named the cortex, which is surrounded by endothelium lining the capsule. In the substance of the lens exist minute stellate clefts. Nutrition (the lens being nonvascular) is by transudation of fluids from surrounding tissues. It is not yet clearly known how waste products are excreted, but probably they are driven inwards towards the centre. The lens increases slowly in size during life by the superimposition of new fibres derived from the anterior endothelium. Any pathological change in the eye affecting the circulation must necessarily affect the lens. . In old age nutritive changes are always seen. In the young adult, however, such changes are so frequently to be seen that I have searched for some cause which may be reasonably held to be responsible. I think this is to be found in glaucoma. In the case of glaucoma the circulation is interfered with to a great extent, and the functions of nutrition and excretion are much depressed. In the first place there is diminution of the quantity;of nourishment. This is brought about by wasting of the ciliary body consequent upon the compression of the filaments of the third nerve and trophic changes due to pressure on other nerves, and by the obstruction to the inflow of blood to all the internal parts of the eye. The quaNty of the nutrient media is lessened, owing to the inflammatory changes existing and the non elimin.ation of waste products, Malnutrition, of course, directly affects the lens itself. The nuclear portion becomes smaller, and there is a certain amount of shrinking of the lens fibres. The stellate clefts are enlarged, and small vacuoles may be found. The cortical portion may be separated from the nuclear, the interspace being filled with fluid causing more or less opacity; or the endothelium may atrophy and become slightly opalescent. In some cases of glaucoma one may see perfect examples of Morgagnian cataract, where the cortex of the lens has undergone liquefaction and the nuclear portion may be made to oscillate visibly in the capsule. This has been mistaken for true displacement ~f the lens. (Vide case below.) Of the remote causes of glaucoma those which seem to me to be the most important are: (a) Heredity; (b) Inbreeding; (c) Distemper. Of these I only wish t6 refer to (b) Inbreeding. Those breeds of dogs which have for generations been inbred for fancy or show purposes seem particularly susceptible to eye troubles, and especially to glaucoma. The result of the glaucoma in these cases· is early seen in the retina, which rapidly commences to undergo pigmentary degeneration. Pigmentary retinitis is seen in human beings as a result of marriages c
GENERAL ARTICLES.
34
of consanguinity, and often affects several members of one family. The same remark applies to dogs, the disease running a protracted course and being quite intractable. The appearance of the retina is easily recognised with the aid of the ophthalmoscope. The pigment is laid down irregularly, and appears as black blotches on the surface of the retina; it seems to follow the course of the vessels, and sometimes to obliterate them. The patient nearly always shows marked photophobia in the earlier stages, and there is evidently a certain amount of pain. Glaucoma is always present, and very frequently the cornea shows some opacity. The condition, though incurable, may perhaps be arrested by sclerotomy and the frequent use of eserine. To sum up the result of my observations-glaucoma is far more common in dogs than has been hitherto supposed. Unless checked early by operation it causes dimness of the lens, and in inbred dogs frequently gives rise to pigmentary retinitis. I quote one typical case (from notes made at the time) showing all three conditions to a marked degree. 22nd Dec. 1903.-Brindle skye terrier with black points, three and a half years old, suffering from glaucoma and keratitis in the right eye, complete blindness, and apparent dislocation of the lens in the left. On the 29th, after treatment with lotions, the cloudiness in the right eye was less marked, but still only an imperfect view could be obtained of the interior of the eye. The dog is totally blind in the left eye, and has only partial vision in the right. He can see nothing directly in front of him, and has only a very imperfect vision of objects to the right of him. He guides himself entirely by the senses of sound and smell. On 9th January 1904, the eyes were very carefully examined with the aid of the ophthalmoscope. The left eye shows apparently complete dislocation of the lens, which is practically floating, and can be made to oscillate by gently swaying the dog's head. l The dog is totally blind in this eye. The right eye shows well developed gla,ucoma, the iris being pressed forward almost against the cornea. The lens is displaced upwards and outwards, and shows partial cataract (stellate). Pigmentary retinitis is present in both eyes, and is similar to the pigmentary retinitis of human beings. This patient is very much inbred (his dam having been mated with her sire), and comes of an already inbred variety. As a puppy he had enjoyed very good health and apparently good sight, and at the present day he is a strong healthy dog, with a good coat, good bone, and straight joints, and in no sense" weedy." The glaucoma no doubt troubles him, and he suffers some discomfort from it making him very depressed. He is highly nervous, and his senses of smell and hearing are very acute-no doubt compensatory. The keratitis is consequent on the glaucoma. I can only account for the displacement of the lens in the right eye by interference with the function of the third nerve. The prognosis in this case is not hopeful, the sight being almost certain to be entirely lost. Treatment consists of soothing and astringent lotions when there is evident pain, and 6!O gr. eserine night and morning to relieve ocular tension. If no benefit is derived from this treatment I intend to perform sclerotomy. 1
This was evidently an error of diagnosis.
The condition was Morgagnian cata,ract.