|Year : 1981 | Volume
| Issue : 1 | Page : 9-11
Timolol in open angle glaucoma
HC Agarwal, NN Sood, Y Dayal
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, Ansari Nagar, New Delhi, India
H C Agarwal
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, Ansari Nagar, New Delhi-29
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Agarwal H C, Sood N N, Dayal Y. Timolol in open angle glaucoma. Indian J Ophthalmol 1981;29:9-11
Timolol-a beta adrenergic blocking agent has recently been tried locally in patients of open angle glaucoma. The drug has been tried mostly in white races. There are only few studies indicating the value of this drug in coloured races. As far as we are aware the efficacy of this drug in Indian patients has not been reported so far.
| Materials and methods|| |
A total number of twenty two cases with sixteen males and six females (36 eyes) of proven primary open angle glaucoma have been included. The age ranged from 39 years to 82 years. Both eyes were involved in fourteen patients and one eye in eight patients. The drug was tried in thirty one eyes who developed side effects to local instillation of pilocarpine, viz. spasm of accommodation, allergy or were not controlled with pilocarpine drops (2% or 4%). Two eyes had high myopia and three eyes had nuclear cataract. The drug was instilled twice a day and then gradually reduced to once a day till the tension remained below 22 mm. Hg.
A general examination of pulse rate, blood pressure was done. Assessment of the condition of the eye including visual acuity with and without correction, slit lamp examination, funduscopy, tonometry, gonioscopy and the scotometry were done. Wherever possible tonography with Barkley tonographer was also done before and 2-4 weeks after timolol therapy.
The associated systemic and local conditions of these patients with open angle glaucoma are listed in [Table - 1][Table - 2]. The follow up period is shown in [Table - 3].
| Observations|| |
The basal intraocular pressure before treatment in thirty six eyes ranged from 22 mm. Hg. to over 40 mm. Hg. [Table - 4]. The percentage fall of intraocular pressure at various intraocular pressure levels with timolol maleate drops in given [Figure - 1]. The number of eyes with control of intraocular pressure is given [Figure - 2]. The comparison of the coefficient of facility of outflow before and after timolol therapy did not show any significant difference.
On comparing the systolic and diastolic blood pressure and pulse rate before starting timolol and at the end of the study no significant change was found.
During the follow up period (varying from 4 wks. to over 50 weeks) no local side effects to timolol were observed in these patients
| Discussion|| |
In the present study the overall control is in the range of 75% eyes. The average percentage reduction depends on the level of basal intraocular pressure before starting the therapy as well as on the strength of the drop used. In the pressure range of 22-25 mm. Hg. 0.25% drop produced average of 27% reduction whereas 0.5% produces 34.8% reduction. Whereas in the pressure range of 26-30 mm. Hg. 0.25% drop produced 23.8% average reduction and 0.5%, 34.2% average reduction of basal tension. Thus there is no significant difference in the average percentage reduction in the two pressure ranges with the same concentration of the drug. But the pressure reducing effect is certainly more marked with 0.5% drops as compared to 0.25% drops.
Of the 24 eyes in the pressure range 22-30 mm. Hg, timolol alone once or twice a day was effective in controlling the IOP to less than 22mm Hg. in 22 eyes (91.6°/). Of the 12 eyes in the pressure range of over 30 mm. Hg, timolol alone once or twice a day was effective in controlling the IOP to less than 22 Hg. mm in 5 eyes (41.6%). Though the pressure reduction in this group was in the range of 25.3% 38.8%, yet it was not sufficient to control the IOP.
Timolol remains a valuable drug in cases of open angle glaucoma developing refractory state or local allergy to pilocarpine, epinephrine; high myopia with or without history of retinal detachment, where use of pilocarpine increases the risk of developing retinal detachment and in cases of open angle glaucoma with nuclear cataract.
Timolol was well tolerated without significant side effects in our cases as reported in other studies also.,,,,,. The drug should be used with caution in patients with high blood pressure, heart block, chronic obstructive lung disease. The long term efficacy of this drug as well as local and systemic side effects still remain to be evaluated in our patients.
The infrequency of administration of this drug, the lack of local side effects and efficacy in open angle glaucoma with myopia and cataract are distinct advantages over the currently available local drugs for the control of IOP in cases of open angle glaucoma. However, the overall control in this series is 75%. If the control is considered for various pressure groups, then the drug is most effective in the pressure range of 22-30 mm. Hg. In this pressure ranges of 22-30 mm. Hg. the control was as high as 91.6%. However, in cases of open angle glaucoma with IOP over 31 mm. Hg., the effectivity was reduced to 41.6%. This observation needs to be substantiated in a large number of cases.
Timolol-a beta adrenergic blocking agent was tried as 0.25% and 0.5% drops in thirty six eyes of 22 patients with chronic simple glaucoma. In the pressure range of 22-30 mms. Hg, the control was adequate in 91.6% of the eyes, but in the pressure range over 30 mms. Hg, the control was adequate in only 41.6% of the eyes. In frequency of instillation, and freedom from spasm of accommodation and pupillary changes proved beneficial in younger age group patients and patients with lenticular changes. High cost and difficulty in supplies precluded its use in other cases.
| References|| |
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Line L.L., Galin, M.A., Obstbaum, S.A. and Katz, I., 1979,. Survey of Ophthalmol. 23 : 377.
[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2], [Table - 3], [Table - 4]