Opinion
The main reason for decreased vision in 25-30% of children is
hereditary, congenital or acquired in an early reward (up to three
years) diseases of the refractive media of the eye, pathology of the
notorious and oculomotor muscles, manifested in anomalies in
the shape, size and refractive power of the cornea, lens of the eye
and their transparency, which leads to anomalies of eye refraction
(myopia, hyperopia, astigmatism), various types of strabismus and
accommodation disorders. These diseases exclude the possibility
of forming a correct, clear visual image, because of which the main
visual function, visual acuity, decreases. The eye diseases listed
above can be unilateral (in one eye), or bilateral-in both eyes
(binocular). However, the latter, as a rule, are more pronounced in
one eye of a child than in the other (paired), as a result of which
the vision of this worse eye is lower than that of the other. From
an early age, the child constantly gets used to using the best eye
for vision, which leads to functional underdevelopment, to a halt
in the development of vision of the paired (worse) eye, and to
amblyopia. Refractive errors (myopia, hyperopia, astigmatism)
lead to the development of amblyopia in 70-85% of ametropias and
unilateral cross-eyed contributes to the occurrence of squinting eye
amblyopia in 80-90% of patients. However, the treatment of such
children is effective only at preschool age.
So, the most effective, simple, affordable treatment method that
does not require visits to eye offices and hospitals (which is very
important, especially for the population of developing countries
with a high birth rate, low income, and an underdeveloped health
care system) is the method occlusion, proposed back in 1743 by J.
L. L. Buffon. As is known occlusion is a complete or partial exclusion
of the best eye’s vision from the act of binocular vision to ensure
visual work with only one, the worst-looking eye for its monocular
visual stimulation. For this purpose, various types of occlude are
currently used, attached to the frame of spectacles in the form of
opaque and translucent paper or plastic films, as well as optical
glass lenses (spherical biconvex or contact lenses). In recent years,
spectacles based on the use of liquid crystal films have also been
offered. However, the types of occlude listed above have several
significant functional and economic disadvantages. The main
ones are: complete exclusion of one eye from the act of binocular
vision; the inability to quantitatively dose and change the degree
of decrease in visual acuity in the best eye during the application
of the occlude; the need for an energy source; the need for frequent
replacement of device elements, as well as the high cost of the
occlude.
In connection with the above, the development of an occlude
that would satisfy the following requirements of ophthalmological
practice remains relevant:
a. Occlude in the form of a simple attachment to the frame of
glasses, correcting the patient’s ametropia.
b. Occlude, providing the ability to quantitatively change the
magnitude of the reduction in vision of the best (leading) eye.
c. Maximum possible simplicity of the occlude design.
d. Ease and low cost of repair work.
e. No need to replace the occlude during treatment.
f. No need for an energy source, and, accordingly, no need to
recharge or replace the batteries used, etc.
g. Minimal weight, optimal appearance, comfort in use
(especially when the device is used by children).
h. Low cost of occlude, available for all segments of the
population (including the population of developing countries
and population of countries with low incomes).