You were probably not too thrilled the first time you were told you needed glasses, but as long as you must wear them, why not learn how they work? Obviously, glasses are made up of lenses and a frame. The frame can be made of plastic, metal, or a combination of the two; its function is to keep the lenses positioned in front of your eyes. The part that sits on the bridge of your nose Ls called, quite logically, the “bridge,” and the handles which it on your ears are called “temples.” Read the rest of this entry »
Lens powers are measured in diopters. The higher the number, the stronger the lens. Plus signs ( + ) are used to indicate reading glasses or magnifying lenses. Minus signs ( — ) are used for indicating distance or reducing lenses. Read the rest of this entry »
Excimer laser treatment is subject to complications, but the complication rate is very low. Patients often ask if one of these complications is likely to occur to them. It is impossible to predict whether a complication will occur in any specific case. Read the rest of this entry »
If you think surgical correction of nearsightedness and/or astigmatism may be for you, the most important choice you will make is the doctor, even more important than deciding whether or not to have the procedure. Read the rest of this entry »
The human eye also belongs to a relatively small group that is equipped to identify different colours. Most insects, fish, birds and many animals can only distinguish different shades and textures. The basis of colour sense is the mixture of three transparent colours — red, green and blue. When they are combined in the correct intensities they make up white. People with a well-developed colour sense can recognize many hues of the same colour, perhaps even as many as a hundred. But colour sense is highly variable, and it is estimated that one male in eight is `colour-blind‘; that is to say, Read the rest of this entry »
These then are the common errors of vision which may cause eye-strain. They are short- and long-sightedness, near-vision deficiency and astigmatism. Most commonly astigmatism is present with one of the other three conditions. They may all be measured by both objective and subjective methods. Objective measurement means the use of instruments, while subjective measurement requires you to state an opinion. In ordinary practice the practitioner will use both methods, and thereby establish a pattern which enables him to prescribe the right optical correction. If you repeatedly give a wrong answer to a subjective inquiry the experienced occulist will proceed to further objective (optometrical) tests. Read the rest of this entry »
The symptoms of eye-strain are diverse and confusing. Inability to use the eyes for a specific task leads to frustration in most intelligent people, regardless of whether such inability is temporary or permanent. There are states where the individual finds that, by squeezing the eyes, or by holding objects at abnormal distances, better vision is possible, but this only leads to fatigue and congestion of the delicate musculature. Read the rest of this entry »
As regards lens-implant surgery the benefits are very great. To be able to have normal sight again without the need for thick spectacles or the bother of wearing contact lenses is surely the preferred treatment. Where contact lenses are used subsequent to a cataract operation, they differ from ordinary contact lenses in certain ways. The condition of an eye that has had its crystalline lens removed is known as aphakia, and aphakia almost invariably demands a contact lens that is much thicker in its centre than the lens worn by the ordinary short-sighted person. Read the rest of this entry »
The results of these preventive measures were disappointing. Some observers reported a slight decrease in the percentage of myopia in schools in which the prescribed reforms had been made, but on the whole the injurious effects of the educational process were not eliminated to any extent.
Further study of the subject has only added to its difficulty, while at the same time it has tended to relieve the schools of much of the responsibility ‘formerly attributed to them for the production of myopia. As the American Encyclopedia of Ophthalmology points out, “the theory that myopia is due to close work aggravated by town life and badly lighted rooms is gradually giving ground before statistics.” Read the rest of this entry »
No phase of ophthalmology, not even the problem of ac- commodation, has been the subject of so much investigation and discussion as the cause and prevention of myopia. Since hypermetropia was supposed to be due to a congenital deformation of the eyeball, and until fairly recently astigmatism was also supposed to be congenital in most cases, these conditions were not thought to call for any explanation or to admit of any prevention; but myopia appeared to be acquired. It therefore presented a problem of immense practical importance to which many eminent men devoted years of labor. Read the rest of this entry »
