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ARTICLES
Year : 1975  |  Volume : 23  |  Issue : 3  |  Page : 6-8

Reflex inhibition of the aqueous flow in the unoperated eye following cataract extraction in other eye


1 Government Medical College, Srinagar, India
2 Institute of Ophthalmology, A.M. U., Aligarh, India

Correspondence Address:
K Nath
Department of Ophthalmology, Government Medical College
India
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Source of Support: None, Conflict of Interest: None


PMID: 1236318

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How to cite this article:
Vaid R L, Nath K, Buch H, Wali V. Reflex inhibition of the aqueous flow in the unoperated eye following cataract extraction in other eye. Indian J Ophthalmol 1975;23:6-8

How to cite this URL:
Vaid R L, Nath K, Buch H, Wali V. Reflex inhibition of the aqueous flow in the unoperated eye following cataract extraction in other eye. Indian J Ophthalmol [serial online] 1975 [cited 2020 Nov 29];23:6-8. Available from: https://www.ijo.in/text.asp?1975/23/3/6/31306

Table 2

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Table 2

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Table 1

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Table 1

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After extraction of an uncomplicated cata­ract, usually there is a decrease in the intra­ocular pressure [3] , facility of outflow [2],[3] and the rate of aqueous formation [3] . Though there are several reports in the literature about the effect of cataract extraction on these values, the effect of operation on the unoperated eye has never been worked out. The present report assesses the effect of cataract extraction on the intra­ocular pressure, facility of outflow, rate of aqueous formation, and ocular rigidity of the unoperated eye.


  Material and Methods Top


Thirty three cases of uncomplicated senile cataract were selected and screened to rule out any concurrent ocular disease. They were subjected to slit lamp and gonioscopic examinations. Intraocular pressure was recorded by applanation tonometer and tonography was performed with the Schwarzer's self-recording tonography apparatus by the standard technique. Facility of outflow was graphically calculated from the Friedenwald's nomogram 1955.

Ocular rigidity was obtained from the Frieden­wald's nomogram after recording the intraocular pres­sure by applanation and Schiotz tonometers. Rate of acqueous formation was calculated by the equation F=C (Po-Pev), where F is the rate of acqueous forma­tion, C is the facility of outflow, Po is the initial intra­ocular pressure obtained by applanation and Pev is the average episcleral venous pressure which in these cases was assumed to be 10 mm Hg.

1-2 days prior to extraction of lens, the tonography was performed in both eyes and was repeated after 6-24 weeks of the operation. Local instillation, known to effect the torographic values, was not used during this period.


  Results Top


In the operated eyes, the intraocular pres­sure, facility of outflow, and the rate of aqueous formation decreased uniformly after the cataract extraction. The ocular rigidity in these eyes was not significantly affected by the removal of lens. These results have been reported in a separate communication. [4]

The results obtained are shown in [Table - 1] and the statistical analysis in [Table - 2].

The intraocular pressure in the unoperated eyes prior to the operation varied from 13 to 19 mm Hg, with an average of 15.26 min Hg. The average intraocular pressure, after the cata­ract extraction in other eye, was 14.44 mm Hg, the range was from 12 to 17 mm Hg. The decrease in intraocular pressure was significant as the calulated T value (2.9) was greater than the tabulated T value (1.96) at 5% level of significance at 32° of freedom.

The facility of outflow (C) in unoperated eye varied from 0.14 to 0.80 ul/mm Hg/mt, with an average of 0.374 ul/mm Hg/mt before the operation and 0.379 ul/mm Hg/mt after the operation, the post-operative range varied from 0.20 to 0.72 ul/mm Hg/mt. The change was insignificant as the calculated T value (0.78) was lesser than the tabulated T value (1.96) at 5% level of significance at 32° free­dom.

The pre-operative ocular rigidity (E) in the un-operated eye varied from 0.016 to 0.037 ul/mm, Hg/mt while post-operatively it ranged from 0.017 to 0.031 ul/mm Hg/mt.. Thus the pre-operative average ocular rigidity (0.023) did not differ significantly from its post-opera­tive average value (0.0225) as the calculated T value (0.74) was lesser than the tabulated T value (1.96) at 5% level of significance at 32° of freedom.

Average rate of aqueous formation (F) in the unoperated eyes prior to operation was 2.09 ul/mt, ranging between 0.42 to 4.80 ul/mt. Post-operatively the average value decreased to 1.64 ul/mt, while the range was between 0.76 to 3.43 ul/mt. The 21 5% decrease in rate of aqueous formation was statistically significant, as the calculated T value (4.18) was greater than tabulated T value (1.96) at 5% level of significance at 32° freedom.


  Comments Top


In our previous studies, [4] it was observed that the intraocular pressure decreases in the operated eye after an uncomplicated cataract extraction, due to a variable state of inhibition of aqueous formation as was also reported by Miller and Hildings [3] . The decrease in the rate of aqueous formation appears to be due to the reflex inhibition of the secretory mechanism of the ciliary bodies, as the scleral rigidity remains unchanged and the outflow facility is actually decreased [2],[3].

In the unoperated eyes, when the compa­rison was made between the intraocular pres­sure, facility of outflow, ocular rigidity and rate of aqueous formation, before and after the operation, it was observed that except for intraocular pressure and rate of aqueous for­mation, these values were not significantly affected by removal of lens in the other eye. Most important and significant effect seen was the decrease in the rate of aqueous formation although not as much is seen in the operated eyes. The statistically significant decrease in the intraocular pressure was secondary to the inhibitation of the aqueous formation. This decrease in the aqueous formation can only be explained on the basis of reflex inhibition of the aqueous formation, due to the surgical trauma to the o her eye, and is likely to im­prove after a variable period as it occurs in the operated eyes.


  Summary Top


To study the effect of cataract extraction on tension, facility of outflow, outflow value, ocular rigidity and rate of aqueous formation, in the unoperated eye, gonioscopy, tonometry and tonography were performed both before and after the cataract operation in 33 eyes.

There was a significant decrease in the rate of aqueous formation in the unoperated eyes which caused a decrease in the intraocular pressure, the other values being normal.

The simultaneous significant decrease in the rate of aqueous formation and intraocular pressure in the unoperated eye is explained by a bilateral inhibition of the centrally controlled secretory mechanism of the ciliary body.

 
  References Top

1.
Grant, W.M., 1951, A.M.A. Arch. Ophthal, 46, 113.  Back to cited text no. 1
    
2.
Lee, P.E. and Trotter, R.R., 1957, A.M.A. Arch. Ophthal., 58, 407.  Back to cited text no. 2
    
3.
Miller, J.E., Kesky, G.R., and Becker, B., 1957, A.M.A. Arch. Ophthal, 58,401.  Back to cited text no. 3
    
4.
Nath, K. and Vaid, R L.. 1971, Ind. J. Ophthal 19,155.  Back to cited text no. 4
    



 
 
    Tables

  [Table - 1], [Table - 2]



 

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