Ophthalmology

“ In recent years the use of different, established, and novel imaging techniques provided detailed insight into several retinal diseases. These modalities provide information about anatomy and functional changes in the retina with high resolution images which improve diagnosis and management of retinal pathologies. ”

“ Medullary nerve-sheaths. Hyperæmia of retina. Detachment of retina. Pigmentation of retina. Hemorrhage in retina. Retinitis. Ophthalmoscopic indications. Disturbances of vision. Different forms of retinitis. Anatomical changes. Neuro-retinitis. Choked disc. Connection with intracranial diseases. Retrobulbar neuritis. Ischæmia retinæ. Anatomical changes in neuritis and neuro-retinitis. Embolism of central artery of retina. Atrophic degeneration of optic nerve. Glioma of retina 439—500
Glaucoma. Glaucoma simplex. Pressure excavation. Differential diagnosis of optic-nerve excavations. ”

“ Ophthalmoscopic Diagnosis of Anomalies of Refraction, of astigmatism 116—119
Ophthalmometer. Corneal curvature in emmetropia, myopia, and hypermetropia. Angle α. Apparent strabismus divergens and convergens 119—125
Diseases of the Ocular Muscles. Movements of the eyes, and laws of diplopia. Centre of revolution. Extent of ocular movements. Laws of innervation. Overcoming prisms. Physiological diplopia. Double images united by prisms 126—134
Paralysis of Abducens. ”

“ So it can be seen that laryngeal phthisis may begin by a variety of symptoms, some common, the others 253rare. It is needless to insist upon the importance of an early diagnosis.
Palmer.
Ball, James Moores.—On Removal of the Cervical Sympathetic in Glaucoma and Optic-Nerve Atrophy.—Jour. A. M. A., June 2, 1900. I propose to consider the surgery of the cervical portion of the great sympathetic nerve in certain ocular diseases. European oculists and surgeons have performed sympathectomy for glaucoma and exophthalmic goiter. ”

“ Diagnosis. Degree of astigmatism. Lens participates in the asymmetry. Directions of principal meridians. Correction by cylindrical and sphero-cylindrical lenses. Stokes' lenses 63—73
Difference of Refraction. Anisometropia 74—76
Paralysis of Accommodation. Differs from presbyopia. Micropia. Paresis of accommodation a symptom of oculo-motorius paralysis. Paralysis of pupillary branches alone. Connection with facial paralysis. Paresis of accommodation after diphtheritis faucium. Traumatic mydriasis and paresis of accommodation 76—82
Spasm of Accommodation. ”

“ Experiment and calculation have gone far to settle the precise mode in which light gives rise to sight, and affects our perception and judgment of external objects, and the condition of the eye during life and health or disease has been brought into view by the ophthalmoscope. The names of Helmholtz and of Donders are inseparably connected with modern advances in the physiology of the eye, while no English name is more conspicuous in regard to the surgery of the eye than that with which we commence this chapter. ”

“ The ophthalmoscope has become an instrument of incalculable value to the oculist. Many changes in the retina and interior of the eye, which are due to disease, can be observed and examined by means of the ophthalmoscope ”

“ Still another way to see the interior is to cut out a piece of the sclerotic about the size of a twenty-five-cent piece; then pinch up and tear out the choroid and the retina under the opening made in the sclerotic. (Fig. 57.) Hold the eye, the cornea forward, close to a bright light, and the image of the light will be seen upon the retina. The closer the light is to the eye, the greater the illumination will be in the [111] interior of the eye. If the opening or “window” is close enough to the optic nerve, the optic papilla can be seen easily. ”

“ Now, you must think of the eye as a lens, but one made up of cells, of tissues. It can know inflammation. As a result of many inflammations there is what we call an exudation—a liquid passes from the tissues. This may be thin or serum-like, or it may be heavier, something like granulations. The tissues are weak—they exude something in their distress, in their attempt to correct this condition when they have been inflamed.
"The pupil of your eye is the aperture, the stop of the lens. That is the hole through which the light passes. Around it lie the tissues of the iris. ”

“ The rudimentary eye would at first merely consist partly of cells sensitive to light, and partly of optical structures [Pg 709] constituting the lens, which would throw an image of external objects upon it, and so convert the whole structure into a true organ of vision. It has thus come about that, in the development of the individual, the retina or sensitive part of the eye is first formed in connection with the central nervous system, while the lenses of the eye are independently evolved from the epidermis at a later period. ”

“ This curious circumstance cannot be owing to the action of light on the inflamed vessels of the cornea; it therefore shews, that the extremity of the optic nerve or retina is also rendered more exquisitely sensible to light, by partaking of the inflammation; and I have been told, that red colours are in these cases sometimes painfully perceived even in perfect darkness. This shews that the retina is excited into motion by the stimulus of light; and that, when it is inflamed, these motions give great pain, like those of other inflamed parts, as the muscles, or membranes. ”

“ All the blood-vessels of the retina pass in and out through the optic disc, and from it diverge into the retina (the larger number branch towards the left side in the direction of the region of the yellow spot) . The brilliant red colour, which surrounds the optic disc, is caused by the light of the ophthalmoscope (reflected from the white inner surface of the sclerotic) , having to pass through the transparent blood-carrying vessels of the choroid. ”

“ It is by the aid of the ophthalmoscope that many obscure diseases are diagnosed, and while it is impossible for every young man who obtains a diploma to become thoroughly proficient in the use of this instrument, yet the eye shows to him many conditions which guide him to the road of successful treatment. Think of a case of optic neuritis—inflammation of the optic nerve—going to an optician and fitting one set of glasses after another until the patient suddenly discovers that blindness is inevitable. ”

“ When cataract is spontaneous, and vision not altogether lost, the patient being able to distinguish bright objects, though unable to direct his steps or follow his avocation—when the pupil is quite sensible to the application or abstraction of light, or to the use of belladonna, &c.,—when all the external parts are sound, the cornea clear, the chambers of the proper size, and no reason to suspect that the retina is affected—the prognosis in regard to the effects of operation is good. ”

“ The shifting of the eye with normal vision is usually not conspicuous, but by direct examination with the opthalmoscope.* When the optic nerve is observed with the ophthalmoscope, movement can be noted that are not apparent when only the exterior of the eye is regarded, it can always be demonstrated. If one eye is examined with this instrument while the other is regarding a small area straight ahead, the eye being examined, which follows the movements of the other, is seen to move in various directions ”

“ The ophthalmoscope has laid bare to our view a living nerve of special sense, the highly-developed end-organ in which it terminates, and the blood-columns circulating in them. In no other part of the body has Nature vouchsafed to us so clear an insight into her mysteries. ”

“ Behind the cornea it forms a curtain, called the iris, which gives to the eye its color. The muscles of the iris contract or relax according to the amount of light received, thus enlarging or diminishing the size of the circular opening called the pupil. The Retina is formed by the optic nerve, which penetrates the sclerotic and choroid and spreads out into a delicate, grayish, semi-transparent membrane. The retina is one of the most essential organs of vision, and consists of two layers. A spheroidal, transparent body, termed the crystalline lens, is situated directly behind the pupil. ”

“ Frequently all endeavours to avert untoward results are unavailing, and the functions of the organ are more or less impaired—the cornea may become opaque, the iris may protrude, the pupil may become irregular, contracted, or obliterated—the crystalline lens may lose its transparency, amaurosis may occur from injury of the retina, the humours may be evacuated, and the eye sink in its socket. The entrance of a large foreign body into the orbit may displace the globe, and cause it to protrude between the eyelids: in such a case the body should be removed and the ball gently replaced ”

“ Numerous other instruments of precision are now in constant use, among the most wonderful of which perhaps is the ophthalmoscope, whereby we are enabled to subject the retina and the intervening media of the eye to minute visual examination. There is not an organ of the body that is not now interrogated daily in the way of physical diagnosis, and we even examine separately the secretion of each of the two kidneys. ”

“ The eyes on the dorsal surface are formed of a cornea, a lens composed of 1-7 cells, and a retina surrounded by pigment; which is perforated in the centre by an optic nerve, the retinal elements being in the inverted position above mentioned.
The development of these eyes has been somewhat imperfectly studied in the adult, in which they continue to be formed anew. They arise by a [Pg 479] differentiation of the epidermis at the end of a papilla. At first a few glandular cells appear in the epidermis in the situation where an eye is about to be formed. ”

“ The retina is not so easily excited into action by less irritation after having been lately subjected to greater. 1. When any one passes from the bright daylight into a darkened room, the irises of his eyes expand themselves to their utmost extent in a few seconds of time; but it is very long before the optic nerve, after having been stimulated by the greater light of the day, becomes sensible of the less degree of it in the room; and, if the room is not too obscure, the irises will again contract themselves in some degree, as the sensibility of the retina returns. ”

“ The chief lymph stream flows from the posterior chamber past the margin of the lens, through the zonula of Zinn, beneath the iris, through the pupil into the anterior chamber, thence through the tissue at the junction of the iris and sclera into the circular canal of Schlemm and from this space into the external lymph channels. Obstruction to the steady escape of the intra-ocular fluids at any point in this drainage system or any undue increase of the fluids themselves may [Pg 103] produce glaucoma. ”

“ The only essential constituent of the visual sense-organ is the retina, which forms so small a part of the eyes of the higher animals; and the simplest eyes are nothing but portions of the integument, in which the cells of the epidermis have become converted into glassy, rod-like retinal corpuscles. The outer ends of these are turned toward the light; their sides are more or less extensively coated with a dark pigment, and their inner ends are connected with the transmissive nerve-fibers. ”

“ The anterior chamber occupies the space between the cornea and the iris, and is filled with a thin, watery fluid called the aqueous humor.
The portion behind the iris forms the posterior chamber, and contains the crystalline lens and a transparent, jelly-like fluid, the vitreous humor. This fluid is never renewed, and its loss is popularly described by the phrase, “when the eye runs out.”
Experiment 149. The retina is not sensitive where the optic nerve enters the eyeball. This is called the “blind spot.” Put two ink-bottles about two feet apart, on a table covered with white paper. ”

“ The optic nerve being seated at the bottom of the eye, has the images of surrounding objects painted upon it; it looks out through the different humors. The different membranes and humours which compose the eye, and serve for vision, are, the tunica conjunctiva, the tunica sclerotica, the cornea, the iris, the pupil, the choroides, and the retina. ”

“ It can be resorted to only in adults, great steadiness on the part of the patient being absolutely necessary. The case, too, must be judiciously chosen. The conjunctiva must be sound, and indeed almost no operation on the eye should be undertaken unless this membrane is in a healthy condition; the cornea should be transparent in every part—the anterior chamber of a proper size—the pupil regular—the iris steady, and not protruded—and the cataract solid; there should be no rolling motion of the eyeball, and no adhesions of the iris. ”

“ Unnatural impressions are made on the retina; flashes of strong light, or luminous sparks, appear to dart across the eyes; darkened spots are seen where none exist; gnats, flies, or other minute bodies, various in colour and brilliancy, seem to flutter before the face; or a single dark speck intercepts the vision. Usually the pupil is dilated and the iris insensible to the stimulus of light ”

“ Neither am I always satisfied with the ophthalmologist's dictum that there is a defect so slight as to need no correction, being well aware, as I have elsewhere pointed out, that even minute ocular defects are competent mischief-makers when the brain becomes what I may permit myself, using the photographer's language, to call sensitized by disease. ”

“ The lens becomes opaque and greenish as the disease advances, vision gradually diminishes, and the iris is immovable. After sight is lost, the patient has a perception of a luminous appearance in the organ when pressed upon. Both eyes are generally affected, one after the other; headache, often violent, attends the disease; many remedies, both external and internal, may be tried on recommendation, though without effect: the disease seldom, if ever, admits of cure. ”