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ARTICLES |
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Year : 1983 | Volume
: 31
| Issue : 3 | Page : 307-311 |
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Penalization in amblyopia
BS Goel, R Maheshwari, H Saiduzaffar
Institute of Ophthalmology, Aligarh Muslim University, Aligarh, India
Correspondence Address: B S Goel Institute of Ophthalmology, Aligarh Muslim University, Aligarh India
Source of Support: None, Conflict of Interest: None | Check |
PMID: 6676246
How to cite this article: Goel B S, Maheshwari R, Saiduzaffar H. Penalization in amblyopia. Indian J Ophthalmol 1983;31:307-11 |
Penalization as a treatment of amblyopia has been advocated by Peter[1]. Haase[2] defined the penalization as cycloplegia with atropine and over correction of the fixing eye with spectacles. However it has not been convincingly established till now as to how penalization helps in improving the vision of the amblyopic eye. The present work has been undertaken with this background to elucidate the effect and mechanism of penalization in the treatment of amblyopia.
Material and Method | | |
67 eyes were studied for measurement of accommodation for near and distance. They included amblyopia due to ametropia, anisometropia, strabismus or combined factors. They were subjected to penalization and followed up at intervals for improvement in vision and accommodation. Penalization consisted of atropine I % ointment in the normal eye daily at bed time to paralyse the accomodation and ptlocarpine 1% drops twice daily in the amblyopic eye to stimulate accommodation and near fixation. Overall attempt was made that the patient uses nonamblyopic eye for distance and amblyopic eye for near. The treatment was carried out for varying interval of 3-6 months with a periodic check on visual acuity and accommodation of either eye. The treatment was stopped when no further improvement was noted for at least 4-6 weeks. The cases were also followed for at least 3-4 months after completing the treatment.
Observations | | |
I. Results of Penalization
Out of 67 eyes which were subjected for penalization, 7 eyes (10.5%) were defaulters and 60 eyes (89.5%) turned up for follow up. Out of these 60 eyes, 44 eyes (73.5%) showed improvement either for near, distance or near and distance both while remaining 16 eyes (26.5%) no improvement was noted either for near or distance (Table 1).
A. Visual acuity for distance:-Out of 60
eyes 39 eyes showed improvement ranging from one to five lines of snellen's chart and rest 21 eyes did not show any improvement. The detail distribution is shown in [Table - 2]. On the whole it was observed that better the initial visual acuity greater was the improvement.
B. Visual acuity for near:-34 eyes out of 60 eyes showed improvement ranging from one to four lines of Jaegers chart and the rest 26 eyes did not show any improvement. [Table - 3] shows the detailed distribution and also reveals that the improvement is directly proportional to the initial vision, so much so that not a single eye with N. 12 or better initial vision failed to show some improvement with penalization.
C. Levels of improvement in visions:-Four
levels of improvement have been described in terms of units taking 6160 vision as 0.1 and 6/6 as 1 according to the American system of representation of visual acuity. Excellent improvement was taken as when the improvement in vision was more than 0.3, good improvement was considered when improvement in vision was from 0.1 to 0.3 and it was taken as moderate improvement when improvement in vision was by 0.1 or less.
For distance 39 eyes (88.6%) showed improvement, out of these 15 eyes (38.7%) showed excellent improvement, 13 eyes (33.3%) showed good improvement and the remaining 11 eyes (28%) showed moderate improvement. This shows that maximum number of eyes showed an excellent improvement.
For near 34 eyes (77.5%) showed improvement, out of which 12 eyes (35.3%) showed excellent improvement and 22 eyes (64.7%) showed good improvement, not a single eye showed moderate improvement. [Table - 4].
D. Improvement according to age:-It was observed that there was no particular relationship in improvement with age, however there was a slight trend of better improvement in early age group. The majority of cases with no improvement belong to the older age group.
E. Improvement related to aetiology:-It was seen that improvement was better in cases who had pure ametropia, anisometropia or strabismus while in cases who had strabismus with ametropia or anisometropia showed poor improvement. As regards the levels of improvement results were better in ametropic group both for near and distance followed by unequivocal difference between the other two groups, while in combined group i.e. ametropia and strabismus & anisometropia and strabismus the results were worst. [Table - 5].
II. Effect of Penalization on accommodation
In 44 eyes which showed improvement in vision by penalization treatment, the accommodation for near improved significantly when compared before and after completion of the treatment for a period of 3-4 months (0.32 D + 0.444 D to 0.65 D + 0.377 D; P < 0.001). However the accommodation for distance did not show any significant improvement when compared before and after completion of the treatment for a period of 3-4 months (2.68 D ± 1.352 D to 2.60 D ± 1.384 D; 0.50 < p). Though the accommodation both for near and distance during the treatment was significantly higher in the amblyopic eye because of the effect of pilocarpine. In 16 eyes which did not show any visual improvement, the accommodation for near as well as for distance did not improve significantly after completion of the treatment for a period of 3-4 months, however during the treatment the accommodation was higher due to the effect of pilocarpine.
Discussion | | |
The technique of penalization is known since 1936. Many authors used penalization in different ways, some only instilled atropine in fixating eye (Cupper 1970[3], Pouliquen 1972[4]) while others combined it with miotics in amblyopic eyes (Knapp and Capabianco 1956); some combined the cycloplegia with overcorrection by glasses (Haase 1974)[2] while others used cylindrical lenses (Weiss 1975)[6]. Several other methods of penalization have also been described such as penalization for near, penalization for distance, total penalization, selective penalization and alternating penalization (Gregerson et al 1974)[7]. But in all these types of penalization the principle remains the same i.e. to blur the vision of fixation eye so as to compel the amblyopic eye to fix for near.
When the overall results of penalization are compared to other methods of treatment such as occlusion, pleoptics, red filter, after image and Cupper's technique, the general conclusion made is that the improvement in vision with all these techniques either separately or in combination varies from 35% to 55%, secondly the improvement is good in children as compared to adults. The results of penalization varies from 77.5% to 88.6%. Thus the penalization has better results than other techniques which have cosmetic problems (occlusion and red filter) and require good co-operation from the patient (Pleoptics, after image and Cupper's technique). On the other hand the penalization is easy to undertake, without any cosmetic problem and does not require much cooperation of the patient.
Even though the advocates of penalization cite an excellant result, Von Noorden and Burian (1974)[8] have not been convinced of its advantages over conventional amblyopia therapy. Von Noorden has questioned the role of penalization on three accounts.
(a) The inhibitary influence originating from stimulating the sound eye is not totally excluded by merely blurring the vision.
(b) Except in mild cases of amblyopia atropinization does not sufficiently decrease visual acuity of the sound eye so that the patient prefers to use the amblyopic eye for fixation.
(c) If total penalization is employed in an emmetropic patient, the child will simply take off his glasses to gain better vision.
But inspite of these so called disadvantages and considering the overall results obtained in the present study it would be justified for a trial of penalization in all the cases. When penalization fails however the patients may be put on pleoptic treatment which is more demanding on the patients co-operation and time. Von Noorden & Milam (1979)[9] also agree with this and recommend penalization in cases in whom occlusion fails and as a therapy to maintain the visual status after stopping the occlusion.
Mechanism of penalization in improving vision
No exact mechanism of penalization is not known till now, but following may be the possibilities.
(1) The improvement in vision may be due to the pinhole effect in the amblyopic eye.
(2) In anisometropes the visual improvement may be by artificial myopia which is induced by ciliary spasm.
(3) Dazzling effect of light on the atropinised fixating eye which causes a tendency to close the eye periodically.
(4) Change in the convergence effect due to change in accommodation may also play a part in improvement in vision.
In a study of accommodation in amblyopia (Goel et al 1981) 10 it has been observed that accommodation is considerably less in the amplyopic eye than the non-amblyopic and control eyes. Pilocarpine increases accommodation during the treatment and the latter therefore helps in improving the vision and when vision improves the accommodation is maintained at higher levels even after stoppage of pilocarpine. Change in accommodation may also play a part in improvement in vision. The over all results also suggest that the improvement in accommodation for near by penalization is directly related to the improvement in vision.
It is therefore felt that accommodation plays a significant role in the mechanism of improvement of vision. It is likely that increased accommodation coupled with pinhole effect prompts the use of amblyopic eye both for near and distance; and the paralysis of accommodation and dilatation of pupil discourages the use of sound eye, both for distance as well as for near.
Summary | | |
The study deals with 67 eyes of amblyopia which were examined with special reference to accommodation for near and distance. They were subjected to penalization which consisted of use of atropine 1% ointment in fixing eye daily at bed time and pilocarpine 1% drops in amblyopic eyes twice a day. Improvement in vision and accommodation were noted during and after completion of the treatment. Accommodation also improved when visual acuity improved. The significance of accommodation in the aetiology of amblyopia and its role in amblyopia treatment has been worked out.[10]
References | | |
1. | Peter, L.C., "The extraocular Muscles. A Clinical study of normal and abnormal ocular motility. ed. 2 Philadelbhia. Lea and Febiger P. 194, 1936. |
2. | Haase, W., Klin Mbl. Augenheilk, 165: 714-724, 1974. |
3. | Cupper, Co, Die Penalization Wiesbabener Tagunj der BVA, Published Arbeitskreis "Schielbehandlung" Bd. 3: 126-131, 1970. |
4. | Pouliquen, P., "The problem of penalization" Klin Mbl Augenhaeilk, 161; 130-139, 1972. |
5. | Knapp, P. and Capobianco, N.M., Amer. orthopt. J., 6. 40, 1956. |
6. | Weiss, J.B., Bull Soc. ophthal. Fr., 75: 277-278, 1975. |
7. | Gregersen, E. Pontoppindan, M. and Rindziunksi, E., Acta. ophthal., (Kbh)., 52: 60 66, 1974. |
8. | Von Noorden, G.K., and Burian, H.M., "Binocular vision and ocular motility. Thsory and managment of strabismus," pp. 427-429. The C.V. Mosby company St. Louis, 1974. |
9. | Von Noorden, G.K. and John Milan, B., Amer. J. of ophthal. 88: 511-518, 1979. |
10. | Goel, B.S., Maheshwari, R., and Saiduzzafar, H., Subjected for publication in Indian Journal of Ophthalmology, 1981. |
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]
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