|Year : 1969 | Volume
| Issue : 6 | Page : 256-258
Effect of occlusion treatment for amblyopia at various ages
AM Gokhale, SA Gokhale
|Date of Web Publication||11-Jan-2008|
A M Gokhale
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Gokhale A M, Gokhale S A. Effect of occlusion treatment for amblyopia at various ages. Indian J Ophthalmol 1969;17:256-8
|How to cite this URL:|
Gokhale A M, Gokhale S A. Effect of occlusion treatment for amblyopia at various ages. Indian J Ophthalmol [serial online] 1969 [cited 2020 Jun 5];17:256-8. Available from: http://www.ijo.in/text.asp?1969/17/6/256/38550
| Introduction|| |
The term occlusion is applied to that method of treatment whereby the vision of one eye is obscured either totally or partially, so that the patient is obliged to use the other eye.
Occlusion of the good eye in order to facilitate vision in a deviating eye is a well known and long established practice first advocated by de Buffon. 
Occlusion may be total, where the vision of one eye is completely obscured, or partial in which only the acuity or the field of vision is reduced. Occlusion may also be diagnostic or therapeutic and conventional or inverse. Conventional occlusion is occlusion of the fixing eye and inverse occlusion is that of the squinting eye.
According to Lyle and Jackson,  part-time occlusion along with exercises is also of value and may be used when full-time occlusion is impracticable, while according to Duke-Elder;  intermittent occlusion is not only valueless but harmful, as, firstly, the vision gained by occlusion treatment is rapidly and actively suppressed in the period of non-occlusion and secondly, abnormal retinal correspondence may develop.
The amount of vision recoverable by occlusion depends upon the age of onset of squint and the time for which inhibition has been operative. It is only possible to reclaim the vision which had at one time developed. Occlusion will therefore be relatively valueless in long-established cases which have had a uniocular squint with amblyopia since birth, as well as in those few cases wherein a failure of macular development or a traumatic central lesion has occurred. Till the age of 6, the later the squint develops, the better will be the visual recovery. If the onset of squint is after the age of 6, full vision may be regained. Earlier the treatment, faster the recovery. Feldman and Taylor  found that if visual acuity did not improve with a telescopic lens, the amblyopia did not respond to treatment.
According to Duke-Eider  , in children of 5 to 10 years, 3 to 6 months of occlusion are required for full recovery. In young adults upto 25 prolonged occlusion, if persisted in for sufficiently long. may result in improvement in 50 per cent of cases; but the process is usually arduous and socio-economically difficult to be thoroughly undertaken. At an early stage, an attempt should be made to see if fusion is possible; if it is not so particularly in adolescents and adults, treatment of suppression should be discontinued as it will lead to diplopia.
According to Lyle and Jackson,  therapeutic conventional occlusion is mainly for children from infancy to 8 years old, provided central fixation is present.
Here is a report of 12 cases of adolescents and adults where occlusion treatment was found to be very successful.
| Material and Methods|| |
In all cases, the age of the patient, refraction, visual acuity without and with glasses was noted and the fixation was examined with the visuscope.
In all cases total, full-time and conventional occlusion was carried out. In some highly hypermetropic cases, additional lenses were prescribed for near vision for some days in the beginning of the occlusion treatment till the near vision improved to J1, or J 2 . Wherever possible the addition for near vision was adjusted so that the patient could read the ordinary book print.
The occlusion treatment was supervised and continued for 1 to 6 months. At each visit, the vision with glasses for distance and near was recorded.
| Discussion|| |
From the report it is obvious that younger the age of the patient, quicker the recovery of vision. This has already been noted by several observers but what is surprising is the visual recovery which occurred in patients aged 12 to 19 and even in a case aged 35 ! The vision of the patient aged 35 improved from finger counting 5 feet to 6/36 in a matter of one month. This rapid recovery of course would not have been possible without meticulous care by the patient. These cases indicate that there is a growing realization of unilateral amblyopia. Unless there is eccentric fixation, occlusion treatment should always be tried wherever it is socio-economically feasible.
In one case of eccentric fixation aged 10, the vision improved from 6/60 and N 12 to 6/9 and N5 within 6 months. In this patient, the fixation was only slightly eccentric. In the other case, the patient was 21 years old and the fixation was grossly eccentric. The vision only improved from finger counting 5 feet to finger counting 8 feet in one month. This supports the established fact that the more eccentric the fixation the poorer the outcome.
| Summary|| |
The theory of occlusion treatment and the observations of some important authors are mentioned.
A report of 12 cases on which occlusion treatment was carried out is presented. Two of these cases had eccentric fixation in the amblyopic eye and one patient was 35 years old. It is shown that occlusion treatment can work effectively even at the age of 35.
| Conclusions|| |
1) Occlusion treatment is worth a trial in all cases of amblyopia wherever possible.
2) Younger the patient, faster the visual recovery after occlusion treatment.
3) More eccentric the fixation of amblyopic eye, poorer the result of conventional occlusion treatment
| References|| |
Buffon de: Bull. et Mem. de 1' Acad. de. Sc.. Supp. III, 174, as quoted in 2.
Duke-Elder, S. W.: 'Text-book of Ophthalmology,' Vol. IV, pp. 3915 and 3916.
Feldman. J. B. and Taylor, A. F.: Obstacle to Squint Training-Amblyopia, Arch. of Ophth. 27, 851, (1942).
Lyle T. K. and Jackson S.: `Practical Orthoptics in the Treatment of Squint', pp. 277, 280, 282.
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