A COMPARATIVE STUDY OF TOPICAL BETAXALOL AND TIMOLOL FOR THEIR EFFICACY AND SIDE EFFECTS

Primary open angle glaucoma is one such field in Ophthalmology where ophthalmologists have failed to stop blindness due to it. Despite of much experimental, clinical and even speculative work, the aetiology of primary open angle glaucoma still remains obscure and hence, treatment is just empirical.[2] All the available treatment modalities are directed towards the reduction of intraocular pressure (IOP) but without interfering the


INTRODUCTION
Eye is that special sense of organ, which makes an individual physically, mentally, socially and economically effective. Loss of function of the eye is blindness. Blindness is a common and distressing complication of glaucoma. It accounts for blindness in 5 million population of which 3 million is due to primary open angle glaucoma (POAG) throughout the world. [1] Primary open angle glaucoma is one such field in Ophthalmology where ophthalmologists have failed to stop blindness due to it. Despite of much experimental, clinical and even speculative work, the aetiology of primary open angle glaucoma still remains obscure and hence, treatment is just empirical. [2] All the available treatment modalities are directed towards the reduction of intraocular pressure (IOP) but without interfering the Correspondence: Dr. Bhandari Akshay Jawaharlal. Department of Ophthalmology, Pravara Institute of Medical Sciences and Rural Medical College, Loni, Ahmednagar, Maharashtra, India. Email: kiwis143@gmail.com basic aetiopathogenesis. Hence at the most blindness due to primary open angle glaucoma is delayed, but not eradicated in present study. As the functional damage in glaucomatous eye is attributed to elevated intraocular pressure, the basic aim of treating glaucoma whether medical, surgical or laser is to control the intraocular pressure. [3,4,5] Primary open angle glaucoma being a slowly progressive disease remains asymptomatic in more than 50% of patients till gross diminution of vision or field occurs.1 In such a situation, to the patients laser or surgical therapy may sound high for the disease. This is one of the reasons for the acceptability of medical therapy apart from other modalities being still under long term study. [5,6] Among the available drugs, there is always a constant search for the best in terms of efficacy, safety and economy. [7] The commonly used drugs in the treatment of primary open angle glaucoma are beta adrenergic antagonists. [8,9,10] Beta blockers reduce the IOP by decreasing aqueous humor formation. The most commonly used drugs in this group are Timolol and Betaxalol. drugs.
In this study we proposed to study efficacy, potency and adverse effects of topical Timolol and Betaxalol in primary open angle glaucoma. At 20 weeks out of 25 patients receiving Timolol maleate 2 patients showed decrease in visual acuity by one Snellen's line. In the Betaxalol hydrochloride group, only one patient showed decrease in visual acuity by one Snellen's line. (Table 3) In our study, it was very difficult to evaluate the visual fields in the class of patients (poor and literate) studied. Also the presence of lenticular opacities interfered with correct assessment of visual fields. There was no change in the visual fields throughout the study period in either group. (Table 4) In both the study groups we found no change in the cup disc ratio in any patients. (Table 5) Of 25 patients who received Timolol maleate, 2 patients (8%) developed mild stinging after instillation of the drug, while in the Betaxalol hydrochloride group 8 patients (32%) complained of mild to moderate stinging for few minutes after instillation of the test drug. In either group discontinuation of the drug was not required. In Timolol maleate group 4 patients (16%) complained of discomfort and tearing was seen in 3 patients (12%). Only one patient (4%) complained of photophobia. In Betaxalol hydrochloride group one patient (4%) complained of itching and 7 patients (28%) complained of discomfort. (Table 6).

DISCUSSION
Medical therapy is usually the first line of approach in POAG. The mainly used drugs in the treatment of POAG are beta adrenergic blockers. [3] Beta adrenergic blockers reduce IOP by decreasing aqueous formation. [4] In this study a total of 50 patients with POAG were studied. 25 patients were treated with 0.5% Timolol maleate ophthalmic solution and 25 patients were treated with 0.5% Betaxalol hydrochloride solution.
In the follow up after 20 week, the decrease in IOP were highly significant (P<0.001) with Timolol. In both the study groups we found no change in the cup disc ratio in any patients. Our findings are in accordance with the previous studies.

CONCLUSION
In the light of these results, we conclude that both Timolol and Betaxalol are effective in decreasing IOP in POAG patients. The magnitude of Timolol in decreasing IOP is more as compared to Betaxalol. The selective beta 1 adrenergic inhibition of Betaxalol provides an added benefit for those patients in whom beta 2 blockade could be harmful.