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ARTICLES
Year : 1982  |  Volume : 30  |  Issue : 4  |  Page : 269-271

Quantitative assessment of ocular anaesthesia by anesthesiometer, orbiculomyometer distantometer and tonometer


Deptt. of Opthalmology, R.N.T. Medical College, Udaipur and S.M.S. Medical College, Jaipur, India

Correspondence Address:
H S Chundawat
Dept, of Ophthalmology, R.N.T. Medical College Udaipur, Rajasthan
India
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Source of Support: None, Conflict of Interest: None


PMID: 7166402

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How to cite this article:
Chundawat H S, Punjabi M K. Quantitative assessment of ocular anaesthesia by anesthesiometer, orbiculomyometer distantometer and tonometer. Indian J Ophthalmol 1982;30:269-71

How to cite this URL:
Chundawat H S, Punjabi M K. Quantitative assessment of ocular anaesthesia by anesthesiometer, orbiculomyometer distantometer and tonometer. Indian J Ophthalmol [serial online] 1982 [cited 2020 Feb 17];30:269-71. Available from: http://www.ijo.in/text.asp?1982/30/4/269/29446

An ideal anaesthetic should have an early onset, sustained effect and with minimum side reactions. For ophthalmic surgery it should produce complete akinesia, analgesia, anaes­thesia, dilated pupil and lower intraocular tension.

There is no unanimity about the strength of lignocaine hydrochloride to be used and whether alone or in combination with adrenalir and hyaluronidase. Higher concentrations may not add to the effectiveness. The present study was conducted for critical, quantitative evalua­tion of presently used anaesthetic and to re­commend the balanced ocular anaesthesia.


  Materials and methods Top


One hundred and twenty patients were the subjects for this study. Lignocaine 1%, 2% and 4% alone and in combination with epine­phrine (1:80,000) and hyaluronidase (50 1.U./ ml) were tested. The behaviour of corneal sensations, orbiculus oculi muscle power, change in pupillary size and intraocular pres­sure were measured quantitatively by using anesthesiometer, orbiculomyometer and dis­tantometer tonometer respectively.

Anesthesiometer used for this study was re­constructed using the principle of Boberg Ans[1] which consisted of graduated cylinder with a piston and nylon thread attached to it. The free end of the nylon thread was touched to the cornea and touch sensations felt by the patient were recorded. Definite touch point was just twisting of nylon thread in place of its straightness. The readings so obtained in millimeters were converted into milligrammes by conversion table. The force required by touch sensations to be appreciated is inversely proportional to the external length of the thread. Size of thread was 0.112 mm. which covered about 4 to 10 epithelial cells contain­ing nerve endings.

Orbiculomvometer was reconstructed on the principle of Muller and Droescher[2] which measured force required to close the eye lids by amplitude of deflection of a pointer which moves on scale. The unit of force is calculated in grammes by using conversion table. The instrument consisted of an eye speculum, to one limb of which was attached an eight centi­meter long pointer and to the other end a scale which was marked from zero to sixty.

Lignocaine hydrochloride (Gesicaine Suhrid Geigy) was the anaesthetic used in vari­ous strengths and effects were studied in the following headings :­

Group A (50 cases) -

Surface analgesia : 1%, 2% and 4% drops of each concentration were instilled in the con­junctival sac and loss of corneal sensations were studied by anesthesiometer.

Group B (40 cases) -

Retrobulbar block : 1 % and 2% concentra­tions of 2 nil were used alone and with hyalu­ronidase and epinephrine. Group C (30 cases)

Facial nerve block: by Obrien's method 1% and 2% concentration of 4 ml were used along and with hyaluronidase.


  Observations and discussion Top


Surface Analgesia - Present study show that corneal sensations disappeared with I drop of Lignocaine 1 % and 2% in an average of 3.5 minutes and duration of anaesthesia was maintained for 10 . 15 minutes. With Lignocaine 4% corneal sensations disappeared in 2 minutes and the effect remained for 10-20 minutes. Intraocular tension and pupillary size were not affected.

Retrobulbar block - 1% solution brought a change in pupillary size from an average of 3.85 mm to 5.40 mm. The effect was observed after 10 minutes and was maintained for total period of 82.7 minutes. The average change in size of pupil after retrobulbar injection of ligno caine 2% alone and when used in combination with epinephrine and hyaluronidase, gives 3.30 mm, 3.20 mm, and 3.05 mm respectively. These changes were maintained for 124, 157.5, and 146.5 minutes respectively. Contrast in pupil­lary dilatation was quite obvious from 1 % to 2% solution alone and when combined with potentiating agents.

Hypotony, relaxation of extra ocular muscles, constriction of arteries and dehydra­tion of vitreous are the advantages of epine­phrine and hyaluronidase.

Intraocular tension recorded an average reduction of 4.46 mm Hg. (Schiotz) with Lignocaine I % : while it was 7.42, 7.51 and 7.50 mm Hg. with Lignocaine 2% alone, combined with epinephrine and hyaluronida respectively.

Average loss of ocular movements wit retrobulbar injection of 2% lignocaine in com bination with epinephrine and hyaluronidas was complete, much quicker (2.01 minutes and lasted for longer (151.0 minutes). Where motor akinesia was incomplete, started Jai (6.16 minutes) and lasted for a short (42.5 minutes) with 1 % solution.

Facial nerve block - By O'berien's method paralysis of orbicularis oculi took place within 5 minutes with Lignocaine 1 % and in 1 . 2 minutes with Lignocaine 2% alone and com­bined with epinephrine and hyaluronidase, Total duration was 30-45 minutes (with 1% solution) and 90-105 minutes with 2% solution in combination with epinephrine and 60-75 minutes with combination of hyaluronidase.


  Summary Top


It is concluded that the use of 4% ligno­caine for surface anaesthese is the best. Ligno­caine 2% when combined with epinephrine and hyaluronidase has an early onset, sustained and complete effect after retrobulbar injection and facial nerve block. The effect remained for quite a sufficient period during which intraocular surgery could be performed well, With 1% and 2% solutions alone the effect was delayed and incomplete and lasted fora t shorter duration.


  Acknowledgement Top


Authors express their sincere thanks for kind guidance and help rendered to them by Late Dr. Saket Bhatnagar, and Professor R,G, Sharma.

 
  References Top

1.
Boberg Ans, 1955, Brit. J. Ophthalmol„ 39:105.   Back to cited text no. 1
    
2.
Muller and Droescher, 1938, : Text Book of Ophthalmology, Duke E'der London, p. 5165.  Back to cited text no. 2
    




 

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