|Year : 1965 | Volume
| Issue : 4 | Page : 137-143
Role of glycerol in ophthalmology
SRK Malik, GC Sood, DK Gupta, RK Seth
Department of Ophthalmology, Maulana Azad Medical College, New Delhi, India
|Date of Web Publication||25-Feb-2008|
Department of Ophthalmology, Maulana Azad Medical College, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Malik S, Sood G C, Gupta D K, Seth R K. Role of glycerol in ophthalmology. Indian J Ophthalmol 1965;13:137-43
The role of glycerol in reducing cerebral oedema in rabbits and neurological cases was demonstrated by Bovet et al (1961) and Vimo et al (1961). It was further shown, that glycerol when administered through a gastric tube in rabbits, lowers the artificially raised intra ocular pressure (Virno et al 1961). The satisfactory results obtained in experimental animals led to its use in ophthalmology in the treatment of glaucoma (Virno et al 1963, Thomas 1963, Casey et al 1963, Charan and Sharma (1964) and Sood et al 1964).
Glycerol is a clear, colourless sweet, viscous liquid miscible with water with a specific gravity of 1.26 and molecular weight of 92. Chemically it is a trihydric alcohol. In ophthalmology it has also been used to reduce corneal oedema ( Duke Elder 1962) and as a corneal preservative (King et al 1962, Dohlmann 1963).
Glycerol is rapidly assimilated from the intestinal tract (Edmunds and Gunn 1936) and is oxidized in the liver to glucose and glycogen (Sollman 1957).
The extremely low toxicity of glycerol and its effectivity by oral route makes it an ideal drug for trial in cases of glaucoma with raised intraocular pressure. Acute rise of intraocular pressure is an ophthalmic emergency and various treatments both local and systemic have been suggested to bring it down to safer levels. The prognosis of surgical intervention in acute glaucoma is better if it is performed on an eye with controlled tension, rather than on one with a high tension. Drugs used systemically for this purpose generally fall into two groups: carbonic anhydrase inhibitors and osmotic agents. Carbonic anhydrase inhibitors along with miotics are very frequently used these days but there are still some cases which fail to respond to this therapy. Intravenous urea has also its protagonists. It acts by virtue of increasing the osmotic pressure of blood. [Crews and Davidson (1961), David, Duch And Javid (1961)], but various side effects i.e. anorexia, nausea, vomiting [Grollman and Grollman (1959)] cyanotic pallor, [Crews and Davidson (1961)], local thrombophlebitis [David and Javid (1961)] and local tissue necrosis Watkins et al (1961), limit its use. It is also unsafe in cases with hepatic and renal insufficiency.
Other osmotic agents which lower the intraocular pressure have side effects which contra-indicate their use, i.e. sucrose for its nephrotoxic effect; sorbitol for its intravenous use (Bellows et al 1938); mannitol for its tendency to cause local thrombophlebitis and pain,.its usage is contraindicated in cardio vascular insufficiency, general debility and oligurea [Weiss, Shaffer and Wise (19612) Smith and Drance (1962.)].
| Present Study|| |
In cataract surgery of today, with improved techniques of akinesia, anesthesia and premedication, the incidence of vitreous loss has been reduced considerably. Reduction of tension below the normal level before commencing cataract surgery had been attempted through Diamox, [Agarwal and Malik (1957)], intravenous urea [Kornbluth and Gombos (1962), I Friedman Byron and Taintz (1962)]. These drugs have also been tried in cataract complicated with raised tension with good results, but there are certain patients who do not respond to these measures.
This study has been undertaken with a view to assess the tension lowering effects of glycerol in the following ocular conditions.
Normal eyes ... 11
Glaucoma of all types ... 52
C) 1 Cataract: normal cases ... 72
C) 2 Cataract with secondary glaucoma due to swollen hypermature cataract. ... 3
D) Post operative hyphema ... 5
E) Delayed formation of anterior chamber 5
The dose of glycerol administered was 1 gm. per kilogram body weight. In those cases where the original tension measured over 50 mm. of Hg. 1.5 grams per Kg. body weight was given.
In case of hyphema and delayed formation of anterior chamber 1 gram per Kg. of body weight of glycerol was given twice a day for 4 to 5 days. The patients who developed vomiting were given largactil. Before administration, glycerol was diluted to 50% with normal saline and lime juice added to make it more palatable.
Intraocular pressure was taken with Schiotz tonometer, the patient being in recumbent position. The tension was recorded by the same observer with the same tonometer every 15 minutes for the first 1 hour, half hourly for the second hour, and then hourly for 6 to 8 hours in normal and glaucomatous eyes. In normal cataract cases the tension was taken 30 to 45 minutes after the administration of glycerol. In glaucoma cases, besides the tension the effect of glycerol on the size and the reaction of pupil, conjunctival and ciliary congestion, relief of pain, diminution of corneal haziness and improvement in vision were also recorded.
Our observations are summarized in [Table - 1],[Table - 2],[Table - 3],[Table - 4],[Table - 5],[Table - 6]. Marked improvement in subjetive signs and symptoms were noticed in cases suffering from acute congestive glaucoma. [Table - 1],[Table - 2],[Table - 3],[Table - 4],[Table - 5],[Table - 6].
Administration of glycerol in cataract cases resulted in the fall on intra ocular pressure in 30 -45 minutes ranging from 5.0 to 7.6 mm. Hg, greatly facilitating cataract extraction. However in 4 cases the very low tension caused some difficulty in extracting the lens specially while doing the operation with the Smith Indian technique. In 19 cases where the capsule accidentally ruptured there was some difficulty in removing the capsule and cortical remnants due to very low tension and the shrinkage of the vitreous.
Out of 5 cases of delayed formation of the anterior chamber two formed the next day, one on the third day, and the remaining two in 5 to 6 days time.
Out of 5 cases of hyphema, two cleared in two days, one on the 4th day and the remaining two within 5 to 6 days.
The seven graphs of intraocular pressure with oral glycerol in different groups show the pattern of action in the groups.
Side effects: Out of 137 cases of various types studied 18 showed side effects like nausea, vomiting, diarrhoea and cough (See [Table - 6]). These symptoms were generally mild and of short duration.
| Discussion|| |
The present 'study was undertaken to assess the effect of glycerol in normal eyes and in various eye conditions, especially its effects in glaucoca and on pre-operative cataract cases.
In the majority of the normal eyes studied, a maximum fall of I.O.P. was recorded after 30 to 90 minutes, though it was delayed upto 2 hours in one case. This is in general agreement with the findings of Virno et al (1963) and Charan and Sharma (1964). Recording of the tension every 15 minutes in the first half hour enabled us to detect the maximum drop as early as from 30 to 45 minutes, in 3 out of 11 eyes.
This lowering of tension of a moderate order (6.0 mm.) is of great benefit in reducing the complications during extraction of cataract (See [Table 7]). However the capsule appeared to rupture more easily (19 eyes out of 72). Again, once the capsule ruptured it was more difficult to coax out the lens matter lying and hiding behind the iris, between it and the shrunken vitreous. This temporary shrinkage of vitreous in the immediate post-operative period, however helps proper apposition of the wound without iris prolapse and promotes reformation of the anterior chamber, (See [Table - 5]). Similarly- glycerol helps in cases of delayed reformation of the anterior chamber when it remains flat after a cataract operation.
The role of glycerol in management of glaucoma is very encouraging. In acute congestive glaucoma the average fall was of 44 mm. This reading compares fairly well with those of Virno et al (1963), Charan et al (1963). We observed that fall in intraocular pressure was greater in eyes where initial tension was higher. This parallelism between the initial tension and maximum fall after oral glycerol has not been reported by earlier authors.
In chronic simple glaucoma the average maximum fall of intraocular pressure was of the order 19.8 mm (average), while in secondary and absolute glaucoma cases this average fall was 26.6 and 28.8 respectively. Refractory cases of glaucoma which failed to respond to Diamox and miotic therapy responded fairly well to glycerol and the maximum, minimum and average fall was 57, 7 and 32.7 mm. respectively. It was only with the help of glycerol that we were able to bring the tension to safe operation levels. (See graphs).
In 5 cases of post operative hyphema glycerol was given to see if it could help it in the absorption of hyphema. The results were equivocal. The number of cases studied in hyphema and delayed formation of anterior chamber are too few to make a categorical statement.
The side effects like nausea, vomiting, mild diarrhoea and retching were mild and transitory and did not require any symptomatic treatment except in two cases where largactil was given. Virno et al (1963) Thomas (1963), Cases (1963) and Charan (1964) observed mild headache in a few of their cases, but none of our cases complained of headache.
| Summary|| |
The effect of orally administered glycerol on intraocular pressure in normal and glaucomatous eyes (angle closure, chronic simple, secondary, absolute glaucoma, refractory cases of glaucoma) and its pre-operative effectiveness as in cataract surgery and in the treatment of hyphema and delayed formation of anterior chamber were studied and have been commented upon.
Its ocular hypotensive effect was more evident in cases of angle closure glaucoma and secondary glaucoma.
A parallelism was observed between the initial tension and the degree of fall in the I.O.P. except in cases of absolute glaucoma.
Glycerol is effective even when Diamox and miotics fail to laver the I.O.P.
The incidence of complications during cataract extraction (75 eyes) and in the post operative period was much less where the drug was given. Glycerol was very valuable in extraction of the hypermature cataract with high tension.
Results were equivocal in hyphema and delayed formation of anterior chamber.
Only mild side effects i.e. nausea, vomiting, diarrhoea retching were observed in 17 cases.
Its use is recommended routinely as a pre-operative measure in cataract extractions, with or without raised tension. It is particularly useful in acute congestive and secondary glaucomas and in those refractory cases where acetazolamide and miotics have failed to lower the tension.
| References|| |
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[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]