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   Table of Contents      
ORIGINAL ARTICLE
Year : 1992  |  Volume : 40  |  Issue : 1  |  Page : 5-8

Ultrasonic study to see the effect of topical pilocarpine and homatropine on anterior chamber depth in phakic cases


Department of Ophthalmology, Dr. S.N. Medical College, Jodhpur, India

Correspondence Address:
A S Mehrotra
Department of Ophthalmology, Dr. S.N. Medical College, Jodhpur
India
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Source of Support: None, Conflict of Interest: None


PMID: 1464455

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  Abstract 

Pilocarpine and Homatropine are the drugs having known effect on the depth of anterior chamber. The purpose of this study was to demonstrate the time of onset, peak effect and its duration of action as well as shallowing/deepening of the anterior chamber, after single instillation of pilocarpine 2% or homatropine bromide 2%, topically in one eye. Also we tried to see if there is any effect on the contralateral eye, due to systemic absorption of pilocarpine, homatropine after topical instillation of the drug in one eye. Pilocarpine causes a measurable shallowing of the anterior chamber with onset of effect with in 20 minutes and a peak in 60 minutes, the average narrowing being 0.26 mm. (range 0.20-0.29 mm.). Homatropine has a measurable deepening effect on the anterior chamber, due to axial flattening of the lens because of cycloplegia, with a range of 0.33 to 0.36 mm. In 70% of the cases the effect passes away with in 24 hours., but in 30% it comes to normal in 48 hours.

Keywords: Pilocarpine, Homatropine Bromide, Ultrasonic Biometry, A--Scan, Anterior chamber, Mydriasis, Cycloplegia.


How to cite this article:
Mehrotra A S, Gupta I, Chouhan B S. Ultrasonic study to see the effect of topical pilocarpine and homatropine on anterior chamber depth in phakic cases. Indian J Ophthalmol 1992;40:5-8

How to cite this URL:
Mehrotra A S, Gupta I, Chouhan B S. Ultrasonic study to see the effect of topical pilocarpine and homatropine on anterior chamber depth in phakic cases. Indian J Ophthalmol [serial online] 1992 [cited 2019 Nov 17];40:5-8. Available from: http://www.ijo.in/text.asp?1992/40/1/5/24412



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  Introduction Top


Pilocarpine and Homatropine are the drugs having known effect on the depth of anterior chamber. Pilocarpine produces a decrease in depth of anterior chamber and also increases facility of aqueous out­flow. Homatropine, a parasympatholytic drug has cycloplegic effect and cause paralysis of accom­modation. The effect can be estimated by movement of the viewing system of a slit lamp as well as ultrasonographically. The former method cannot he so accurate hence the latter was tried in the present study. The ultrasonic biometer is a microprocessor based digital instrument that uses pulsed ultrasound to determine intraocular dimensions. The purpose of this study was to demonstrate the time of onset, peak effect and its duration of action as well as shallowing/deepening of the anterior chamber, after single instillation of pilocarpine 2% or homatropine bromide 2%o, topically in one eye. Also we tried to see if there is any effect on the contralateral eye, due to systemic absorption of pilocarpine, homatropine after topical instillation of the drug in one eye. Such detailed study, specially of Homatropine is not avail­able in the literature.


  Material and methods Top


The study was conducted in the out patient, Depart­ment of Ophthalmology, of Dr. S.N. Medical College, Jodhpur. The A Scan used to measure the depth, of the anterior chamber, was the Humphrey Ultrasonic Biometer 810 using a frequency of 20 Mhz.

Measurement of the effect of topically instilled pilocar­pine 2% / homatropine bromide 2% single instillation, were done in 25 volunteers of each group. In the age group 20-60 yrs. in the Pilocarpine group and 20-40 yrs in the Homatropine group a complete ocular examination was done in each case, before hand, including Schiotz tonometry to rule out any other ocular disease affecting the procedure.


  Observations Top


The readings, after instillation of the drug, were made at an interval of 20 minutes. till 2 hours and then at 24 hours. and 48 hours. The measurements were first made in straight ahead position using ultrasonic transducer, while the contralateral eye fixed on a target placed at 1 meter and 6 meters distance respectively, after topical anaesthesia with 4% Xylocaine. A-Scan demonstrated the changes in depth of A.C. due to changes in the anterior surface of the lens.

The contralateral eye had hardly any effect due to systemic absorption of pilocarpine, when a single instillation is done in one eye.

Shows effect on contralateral eye. after single instil­lation of Pilocarpine 2% in one eye. The contralateral eye has hardly any effect due to systemic absorption of Pilocarpine.


  Results Top


Pilocarpine Group:

A single instillation of Pilocarpine 2% in one eye shows marginal shallowing of the anterior chamber by an average of 0.26 mm (range 0.20 - 0.29 rnm) The difference for distance and near is not appreci­able. Normal depth of the A.C. recorded in the age group 20-60 years was 3.00 mm. for near and 3.03 mm. for distance (6 M). Systemic absorption has practically no effect on the contralateral eye.

Homatropine group

A single instillation of Homatropine 2% in one eye has a deepening effect, which starts with in 20 minutes., is maximum in 60 minutes and gradually becomes normal in 24 hours time in 70°% of the cases and base line in 48 hours. Minimum and maximum depth change recorded was 0.33 min. and 0.43 mm. respectively from the initial (average) depth of 3.44 mm.


  Discussion Top


The effect of a single instillation of Pilocarpine 2%, on normal eyes was observed in this study. The effect of Pilocarpine on the anterior chamber depth was recorded within 20 minutes, maximal within 60 minutes and practically vanished after 120 minutes. The average change in anterior chamber depth was 0.26 mm. which can be compared with the meas­urements of Abramson et al [1] (0.29 mm), whereas in 31.20 of eyes the effect wore off at 24 hours. This difference might be on account of various age groups included, refractive error of the eyes and elasticity of the lens also. Other factors were sex, occurrence of anile closure glaucoma and the outflow facility. Romano found the anterior chamber depth significantly lower on eyes with open angle glaucoma. In our study we found the minimal change in anterior chamber depth was 0.6 mm. in 50-60 years age group which is less than in the age group above this. After instillation of (Pilocarpine) miotics, Rosengren found an average reduction of 0.16 mm. in chamber depth in patients under 45 years of age but no significant change in elderly patients. He also noted the maximal effect on anterior chamber depth within 30 minutes, (he did not measure sooner than 30 minutes) and disappearance of the effect by 90 minutes. Wilkie [7] et al observed narrowing to remain upto the sixth hour after the single topical instillation of pilocarpine 2%.

We observed no change in the anterior chamber depth due to systemic absorption of 2% pilocarpine instilled in the contralateral eye ( in which no instil­lation was done) although Chahar and Dhaka [2] found significant lowering of IOP by Timolol 0.5% in un­treated eyes.

The effect of a single instillations of homatropine bromide 2% on normal eyes was also observed in this study. The effect of homatropine on anterior chamber depth was recorded within 20 minutes, maximal within 60 minutes and the effect wore off within 24-48 hours. The increase in the depth of anterior Chamber is due to axial flattening of the lens because of cycloplegia. The readings of anterior chamber depth at a distance of 1 meter and at 6 meters were almost same. This suggests that there was paralysis of accommodation due to cycloplegia.

This study with homatropine is our pioneer effort, as such a study is not reported in literature as yet. As in the case of Pilocarpine no effect could be seen in the contralateral eye.


  Summary Top


High resolution ultrasonic biometry was performed on two groups of 25 each, prior to and at regular intervals, after a single topical instillation of Pilocarpine 2% / Homatropine 2%. Pilocarpine causes a measurable shallowing of the anterior chamber with onset of effect with in 20 minutes and a peak in 60 minutes, the average narrowing being 0.26 mm. (range 0.20 - 0.29 mm.). Homatropine has a measurable deepening effect on the anterior chamber, clue to axial flattening of the lens because of cycloplegia, with a range of 0.33 to 0.36 mm. In 70% of the cases the effect passes away with in 24 hours., but in 30% it comes to normal in 48 hours.

 
  References Top

1.
Abramson D., Coelman J.. Forbes M, and Franzen L : Pilocarpine, effect on the anterior chamber and lens thickness. Arch. Ophthal. 87, 615. 1972.  Back to cited text no. 1
    
2.
Chahar A. and Dhaka R.L.: Bilateral effects of monocular instillation of 0.5% Timolol maleate in glaucomatous and normal subjects. 48th Conference of A I.O.S. at Ahmedabad. 1990.  Back to cited text no. 2
    
3.
Coelman, D. J.. Ophthalmic biometry using ultrasound. Int. Ophthalmal. Clin. 19(4) 225-235, 1979.  Back to cited text no. 3
    
4.
Lowe R.F: New instruments for measuring anterior chamber depth and corneal thickness. A.J.O. 62; 7. 1966  Back to cited text no. 4
    
5.
Perkins E.S.: Depth measurement with the slit lamp microscope. B.J.O. 72, 344-347, 1988.  Back to cited text no. 5
    
6.
Romano J. : Anterior chamber depth in medically treated open angle glaucoma. B.J.O. 52, 361, 1968.  Back to cited text no. 6
    
7.
Wilkie J., Drance S. and Schuler M : The effect of miotics on anterior chamber depth. A.J.O. 68, 78: 1969.  Back to cited text no. 7
    


    Figures

  [Figure - 1], [Figure - 2]
 
 
    Tables

  [Table - 1], [Table - 2], [Table - 3], [Table - 4]



 

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  In this article
Abstract
Introduction
Material and methods
Observations
Results
Discussion
Summary
References
Article Figures
Article Tables

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