Year : 1979 | Volume
: 27 | Issue : 4 | Page : 113--115
A comparative study of trabeculectomy in cases of chronic simple glaucoma
S Mital, P Avasthi, N Anand
Medical College, Agra, India
Pool Officer, Medical College, Agra
|How to cite this article:|
Mital S, Avasthi P, Anand N. A comparative study of trabeculectomy in cases of chronic simple glaucoma.Indian J Ophthalmol 1979;27:113-115
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Mital S, Avasthi P, Anand N. A comparative study of trabeculectomy in cases of chronic simple glaucoma. Indian J Ophthalmol [serial online] 1979 [cited 2020 Sep 23 ];27:113-115
Available from: http://www.ijo.in/text.asp?1979/27/4/113/32595
Embarrassment of drainage of aqueous being the dominant factor, glaucoma surgery should aim at measures to facilitate the outflow of aqueous. Based on a similar thinking that the seat of resistance in simple glaucoma is the trabecular meshwork, is the operation of trabe culectomy. Cairns in his series of 17 trabeculectomies which he followed for a period varying from 20 to 56 weeks, concluded that prolonged control of intraocular tension without obvious subconjunctival drainage of aqueous seems to be possible by this method. The technique of Cairns was modified by Watson in which the lamellar scleral flap was limbus based. Watson described trabeculectomy as the most satisfactory operation, satisfying the major rules of surgery.
An attempt has been made to compare the result of trabeculectomy with other glaucoma operations in chronic simple glaucoma.
Materials and Methods
The present study was carried out on 53 eyes of chronic simple glaucoma, out of which 25 cases constituting the contol group were operated by surgical procedures other than trabeculectomy, (11 cases-Scheies', 8 casesIridencleisis and 6 cases-Trephining), 28 constituting the study group were subjected to trabeculectomy.
1. Trabeculectomy group (28 cases)
The average pre and post-operative values have been summarised in [Table 1]. In all the cases, I.O.P. was below 20 mm Hg. post-operatively throughout the follow up period of 54 weeks. Three of the cases could not be followed up after 6 weeks of operation as they did not turn up.
2, Scheies' group (44 cases)
Though the average post-operative I.O.P. was within normal limits, in one case, Scheies' operation proved to be a failure as I.O.P. kept well above 25 mm Hg. inspite of the use of miotics. In this case later on trabeculactomy was done and T.O.P. was controlled.
3. Iridencleisis group (8 cases)
Average I.O.P. post-operatively went beyond normal limits by the 6th week. In one case I.O.PR remained uncontrolled post-operatively and later this eye lost all useful vision as patient did not agree for a second operation. One case showed delayed failure but in this case I.O.P. was controlled with the help of miotics.
4. Trephine group
The average post-operative figures were satisfactory. One case in which cataract extraction was done, later developed aphakic glaucoma. Trabeculectomy was done in this case but a follow up could not be done as patient did not turn up.
Complications : 1. Delayed anterior chamber formation
There was delayed anterior chamber formation in one case in trabeculectomy (3.5%) five cases in Scheies' (45.5%) two cases in iridencleisis (25.5%) and one case in trephining (16.6%) operation.
Iritis was observed post-operatively in 11 cases of trabeculectomy (32%, 4 cases of Scheies' (36.3%), five cases of iridencleisis (62.5%) and two cases of Trephine (33.2%).
Secondary hyphaema developed in one case each of trabeculectomy (3.5%, Scheies' (9.0% Iridencleisis (12.5%) and trephine (16.6%). In case of iridencleisis hyphaema was recurrent and massive, and took nineteen days to resolve, leaving behind corneal staining and high I.O.P. This case remained uncontrolled post-operatively inspite of the use of miotics. In all other cases hyphaema was small, clearing in one to five days and the eyes did well.
Post-operative ocular hypotension of less than 10 mm Hg occured in six cases of Trabeculectomy (21.4%) 4 cases of Scheies' (36.3%), 1 case of iridencleisis (12.5%) and 2 cases of trephine (33.3%). At the end of follow up of 54 weeks only 3 cases of trabeculectomy (10.7%), and in case of trephine, (16.6%) were showing hypotension.
In 5 cases with trabeculectomy (17.8%), 4 cases with Scheies (36.0%) and 2 cases each with iridencleisis (25.0%) ano trephine (33.3%) had either increased or fresh appearance of lenticular changes. In most of these cases there was associated post-operative hypotension.
6. Delayed failure
1 case each of Scheie's (9.09%) and iridencleisis (12.5%) showed delayed failure. In both these cases LO.P. and Facility were controlled post-operatively in a follow up of 6 week, but during further follow up both cases showed a rise in I.O.P. with a fall in facility. In case of Scheies' operation, glaucoma surgery has to be repeated to control IOP and facility but the second case in which iridencleisis was done did not agree for a second operation and lost all useful vision in that eye.
One of the cases in which Trephine was done developed post-operative panophthalmitis as a result of rupture of the thin conjunctival bleb and in this case evisceration had to be done.
In cases of trabeculectomy, no significant complications were observed. In Scheie's, incidence of delayed formation of anterior chamber was highest (45.5%). In iridencleisis besides a high rate of delayed formation of anterior chamber (25%), secondary hyphaerna was a very annoying complication. In trephine, rate of complication was less as compared to Scheie's and iridencleisis the incidence of delayed formation of anterior chamber (16.6%), and post-operative hypotony (33.3%) was much higher as compared to trabeculectomy. Postoperative increase of fresh appearance of lenticular changes was observed in all the four types of operations but the incidence was maximum in Scheie's (27.2%) and lowest in trabeculectomy (10.7%).
54 weeks follow up study of the operated cases revealed that I.O.P. and facility of aqueous outflow were very well maintained in all the cases of trabeculectomy with an average of 13.9 mm. and none of the cases in this group showed delayed failure. However, the incidence of delayed failure was 12.5% in iridencleisis and 9.09% in cases of Scheies'.
Thus study clearly shows that operation of trabeculectomy has got definite advantages over the other operations viz.
1. I.O.P. and facility of aqueous outflow after the operation remains well maintained and delayed failure is rare.
2. Complications are much less and a great advantage is that incidence of fresh appearance or increase in the post-operative lenticular changes is minimum.
Summary and conclusion
53 eyes of chronic simple glaucoma were operated; out of this 28 constituting the study group were subjected to trabeculectomy, and 25 constituting the control, group were operated by surgical procedures other than trabeculectomy viz, 11 cases by Scheies' 8 cases by iridencleisis and 7 cases by trephine.
Complications were minimum in case of trabeculectomy and I.O.P. and facility of aqueous outflow were best maintained in Trabe culectomy group without any delayed failure.
|1||Cairns, 7.E., 1968, Amer. J. Ophthal., 66, 673.|
|2||Watson, P.G., 1969, Trans. Ophthal. Soc. U.K., 89, 523.|