Page images
PDF
EPUB

many hours a day to direct sunlight and light reflected from the water are liable to suffer. Soldiers may also be affected when exercising for many hours a day under a burning sun, especially upon white soil. Night blindness is also a prominent symptom in retinitis pigmentosa. Snow blindness or ice blindness is of the same nature, but in addition to the want of sight there is conjunctival congestion, photophobia and pain, and in some cases conjunctival ecchymosis.

Muscæ volitantes appear as small dots, filaments, or webs, generally transparent, but at times quite dark or even black; they move about in the visual field and do not interfere with vision; they are, however, a source of considerable discomfort and sometimes of anxiety to nervous patients. They are always seen most distinctly in bright light and upon a light surface as when looking at white clouds or white paper, or the pavement in walking.

Muscæ are due to minute changes in the transparent media or films of mucous on the cornea; they are most common in myopic eyes; if they cannot be seen with the ophthalmoscope their presence is of no importance and patients may be assured that they will do no harm.

Malingering.-Patients sometimes wilfully feign blindness of one or both eyes, but are easily detected. If one eye only is affected its pupil acts freely both directly and indirectly; if we put a prism base up or down in front of either eye, the sound one for choice, double images appear, and the patient believing them to be caused by the glass mentions them at once. If a prism is not at hand, double vision can be produced by pressing on the sound eye with the finger so as to make it deviate in any direction. If atropine is applied to the sound eye when it has fully dilated the

pupil and paralysed the accommodation, the patient will read small print easily which of course must be done by the supposed blind eye. This test and that of the action of the pupil will be of no use if the patient has used a mydriatic to his supposed blind eye.

If both eyes are affected we shall soon find out the imposture by watching the patient; he will move about without running against objects, his pupils will act freely; if spoken to suddenly, or if a light be unexpectedly thrown upon the eyes he will give some sign that he sees.

The treatment of functional diseases of the retina, so far as treatment is of any avail, consists in the removal of the cause. Constitutional diseases should be treated, anomalies of refraction corrected, and the surroundings of the patient altered.

PART II.

OPERATIONS.

CHAPTER I.

POSITION OF PATIENT AND OPERATOR, ADMINISTRATION OF ANESTHETICS, USE OF COCAINE, ETC.

ALL the minor operations, such as slitting the canaliculi, passing probes down the nasal duct, opening tarsal cysts, &c., can best be performed when the patient is seated in a chair, and the operator stands behind him; the patient's head, over which a towel has first been thrown, resting against the operator's chest. (See Fig. 31).

The more important operations, as extraction of cataract, iridectomy, squint, etc., should be performed whilst the patient is lying on a hard couch, his head resting on a bolster covered by a towel, thrown forward over the forehead; the operator should sit or stand behind (see Fig. 32). In whichever position an operation is to be performed, the chair or table should be placed in front of a large window so as to insure a good light, and care be taken to prevent assistants and others from interposing their heads or bodies between the patient's face and the source of light. It will be found whilst operating that, with the exception of occasional pronation and supination, there is little occasion to use the arms, which should be kept with the elbows near the sides, the wrists resting on the

patient's head or face, in a position which allows of free movements of the hands and fingers.

Every ophthalmic surgeon should learn to use his fingers, cultivate his sense of touch, and, if possible, become ambidextrous.

[graphic]

FIG. 31.-Position for minor FIG. 32.-Position for major operations. (Sitting).

(From Byrant).

operations. (Lying).

It will be found that incisions can be best made by holding the knife lightly between the thumb and first two fingers of whichever hand is most conveniently situated. phomore

In all operations, incisions commencing at, or situated entirely on, the outer aspect of the globe should be made with the hand corresponding to that side, the opposite hand being employed upon the inner side. That is to say, if the right eye is operated on, the right hand should be used to make an incision at its outer side, the left at its inner, and vice versa.

Incisions above or below may be made with either hand; scissors should also be used with whichever hand is most favourably situated.

In one operation, that for internal strabismus, the positions of patient and operator are somewhat different from those already described, the operator standing in front, at the side of the couch on the patient's right, instead of behind his head.

The scissors may be used with the right hand for both eyes, but in operating on the left the hands will have to be crossed.

Before performing any operation the operator should look carefully to the condition of the instruments he is about to use and see that they are washed in an antiseptic solution. Knives should be passed through a piece of thin leather tightly stretched on a small metal cylinder, and care taken to ascertain that they have good points and that there are no notches in the blades.

Scissors should be carefully examined and tried; it should be seen that forceps close properly, and are free from rust or dirt; silk for sutures should be black, as fine and strong as possible, well waxed, and free from flaws or kinks. Inattention to these details may very

possibly mar the success of an operation.

Antiseptics.-The antiseptic treatment is not applicable to ophthalmic surgery further than the cleansing of all instruments and sponges with 1 to 20 solution of carbolic acid, the soaking of all dressings in boracic acid solution gr. x. to 3j. and cleansing the eye with the same.

Administration of anesthetics.-The operator will find that he has much more command over the eye when the patient is under the influence of an anesthetic than when consciousness remains and in a great number of cases he will do well to administer one. It must, however, be born in mind that in all cases where a large incision has to be made into the globe, as in cataract extraction or iridectomy for glaucoma, the

« PreviousContinue »