|Year : 1983 | Volume
| Issue : 6 | Page : 715-717
Prophylaxis in myopia
R P Dhanda
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dhanda R P. Prophylaxis in myopia. Indian J Ophthalmol 1983;31:715-7
Myopia is a universal disease. It starts around the age of 2-3 years. It is usually progressive upto puberty and in some cases even later. The incidence is definitely on the increase particularly in urban communities. For these and other reasons, the parents and patients both are anxious to know whys and how about myopia. Their principal concern is why glasses at so young age, why the power is increasing every year, what is the future of such patients and what prophylactic measure can help.
It is important to understand from prophylaxis point of view, the back ground of its high and increasing incidence. Early schooling, heavy curriculum, finer prints and finer writing material have all a distinct contribution to the early on-set of the disease and its heavy incidence. The eye in its developing phase can be easily influenced by these environmental factors. Genetics is an important contributory factor too. May be, nutrition also plays an important role. The following, therefore, are important questions to answer from prophylaxis point of view.
CAN MYOPIA BE PREVENTED?
Some degree of prevention can be achieved if a child is not put to school before 6 years preferably 7 years. This has recently been considered important in countries like United States where school going age is extended to 7 years. That it will delay the educational and economic mile stones of the child should be given less importance because a healthier eye and healthier body will compensate for this factor. The present practice of admitting children to Nursery and Kinder-gartan, however innocuous it may appear; is not free from the strain on the eyes of small children. Avoiding consanguineous marriages may be a consideration from genetic point of view.
Another important factor is the heavy curriculum even in the primary classes. The hag of books they carry to school is indicative of the load on the eyes. The lack of interest of teacher and giving heavy home work is an important consideration. Extra tuitions even after coming from school is at the cost of outdoor hours of a child so necessary for his health.
Finer prints of book, finer writing material as against the bold letters, thick pens writing on wooden plates and slates 30 years back is a significant change contributing to the errors of refraction and hence their consideration in prophylaxis.
The developed countries have taken serious note of these factors and have adopted better teaching programme even in Primary schools like audio visual method of teaching. Can the Progress of myopia be arrested ?
Once the myopia starts and the contributory factors continue to operate, progress of myopia is un-avoidable. The parents should be explained that the myopia would continue to progress till the body grows, about 16 years in case of girls and 20 years in boys and that this expected progress should not upset them. In most cases they should expect that the condition will be stablised by the time the child reaches puberty. Some positive efforts maypossibly show, the rate of progress and the parents should there be advised that:
1) The child should have as many out door hours as possible.
2) He should be allowed full scope in studies demanded by the curriculum but he should be discouraged from reading avoidable material like comics etc. It is important that the parents should not allow their weakness to their children to be exploited and should be firm on this matter. They should not buy these children such books. May be sitting before television for hours, is also an important factor and should be discouraged.
3) The parents should be explained that myopic child is like a frog in a well whose world is very small. They have therefore a tendency to interest in close work and shun out door hours. It is the duty of parents to help out these children from the limited world of their own.
4) Reading habits of myopics holding objects too close to the eyes should be corrected by parents.
Would it prevent increase of myopia if the glasses had been started earlier ?
With the morbidity of the deseases as understood, it is unlikely to influence the rate of progress of myopia. Irrespective of when glasses were started soon after joining the school or later in curricular life. Factors like going to school early and occupying the front bench by which the child subconsciously avoids to reach a stage that he becomes conscious and makes his parents conscious that there is something wrong in his eyes. Being a developmental is in most cases pre-determined. The parents therefore need not feel guilty for bringing the child to the ophthalmologists late.
Can diet influence onset of myopia ?
There is no clear cut criteria on this point. It has been suggested that an adequate protein content in food may have some influence. Adequate milk and or an egg a day should be advised to myopic children. Vitamin-D an addition to diet may be considered good.
How often to checkup the glass of myopic children ?
Parents should understand that myopia is a progressive disease and there will be some increase in power every few months. In most cases, a two yearly examination would be adequate. If, however, the child complains earlier that he has stopped being, able to see writing on the black-board, an earlier examination may be necessary and some of these children may be in the group of progressive or malignant myopia.
Can Myopia be reduced by use of contact lens ?
There is no reason to believe that it is so. The contact lens practitioners have emphasised its importance but it is not supported by clinical experience of ophthalmologists. Contact lens will increase the field of vision in high myopia. It can improve visual acuity better than the glasses can do in high myopes. The contact lences may be advisable but not with the hope that it will arrest the progress of myopia.
Ortho-keratology, changing contact lenses every three months and everytime more and more tight fitting lenses, has been claimed to reduce myopia. This claim of contact lens practioners is not substanted in a follow up study and the improvements claimed are only temporary. Myopia returns back to original degree after a few months of transient improvement.
What is the fate of a myopic eye and how to prevent it?
Normally the myopia should be stabilised by puberity. There is a small group of malignant progressive myopia which may continue to progress even beyond puberity. These cases need to be observed and followed up every year not only for checking the glasses but also noting fundus charges if any. Myopic degeneration in such cases starts around the age of 30-40 years and the vision thereafter may deteriorate and not improve with glasses as in earlier years.
These cases of malignant myopia may end in severe visual handicap. This possibility should be explained.
A Common cause of sudden increase in myopia in older age is the nuclear changes in the lens which are typical of myopic pathology. Myopic basis of this pathology is confirmed by the observation that in cases of uniocular high myopia, these changes develop only in myopic eye and not in the normal eye. How to avoid the chances of total blindness in a myopic
One condition which can lead to near blindness are malignand myopia with extensive pigmentary degeneration and chorio-retinal atrophy. These changes affect the vision to a severe degree when the macular area is involved and this is not uncommon in eyes with malignant myopia.
Another complication which may, if not adequately treated, is retinal detachment which is more common in myopic eyes than in non-myopic eyes. In high myopic eyes retina is markedly thinned and the result of retinal surgery may not be as satisfactory as in eyes with moderate myopia.
Another important pathology which directly or indirectly leads to blindness in myopia is the highly degererate vitreous which is not only full of opacities but is also a matter of serious concern in cataract surgery because of more frequent operative and post operative complications.
Prophylaxis of against these serious problems can be changed only to a limited extent. Even otherwise myopia is a disease we have to live with-and mighty little can be done to reduce its incidence. On the other hand, we should be prepared for its increasing incidence and the consequences thereof.