Indian Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 1984  |  Volume : 32  |  Issue : 2  |  Page : 69--72

Subscleral goniotrepanation in primary glaucoma


Mathew Jacob, Anna Thomas 
 Department of Ophthalmology, Christian Medical College, Vellore, India

Correspondence Address:
Mathew Jacob
Department of Ophthalmology, Christian Medical College, Vellore
India




How to cite this article:
Jacob M, Thomas A. Subscleral goniotrepanation in primary glaucoma.Indian J Ophthalmol 1984;32:69-72


How to cite this URL:
Jacob M, Thomas A. Subscleral goniotrepanation in primary glaucoma. Indian J Ophthalmol [serial online] 1984 [cited 2024 Mar 28 ];32:69-72
Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?1984/32/2/69/27373


Full Text

Since its first description by Carins in 1968 the operation of trabeculectomy has under= gone many modifications The popular use of a trephine in glaucoma surgery was adapted to trabecular surgery by Fronimopoulos et al[2] �in the procedure named gonio trepanation, in which the Elliot trephination was covered with a lamellar scleral flap. We conducted a prospective study of 50 eyes in 40 patients who underwent the operation of gonio trepanation alone or in combination with cataract extrac�tion for primary glaucoma.

 MATERIALS AND METHODS



Subscleral gonio trepanation was done in 50 eyes of 40 patients, and in 14 of them it was combined with lens extraction. All the eyes had primary glaucoma, with open angles in 21 cases and angle closure in 29. Their visual status ranged from perception of light to 6/5 and the average intraocular pressure was 40 mmHg. The indications for surgery were primary angle-closure glaucoma (acute or chronic) and primary open-angle glaucoma not controlled with medication. Surgery was also done when the patients could not be trus�ted with regular use of medicine or follow-up. Whenever the lens opacities warranted cat�aract extraction, this also was done along with gonio trepanation.

The procedure of subscleral gonio trepana�tion described by Fronimopulos[3] with a few modification was employed After abroad (10 mm) conjunctival flap and a 5 mm x 5 mm lamellar scleral flap were prepared, a 2 mm Grieshaber trephine was positioned astride the junction of the white an blue zones of the limbus (partly on clear cornea and partly over the trabecular meshwork) and a neat disc was cut with a few turns of the trephine. It was lif�ted up with forceps and any adhesions to the underlying tissue severed with corneal scis�sors. A peripheral iridectomy was performed through the trephine hole and the scleral flap was closed with four or five 8-0 virgin silk or monofilament nylon sutures. The con�junctival flap was closed by a running 6-0 silk suture.

In cases where a combined gonio trepana�tion and cataract extraction was done, a tim�bal section of 160� was made through the trephine hole by corneal scissors and the lens removed by a cryoprobe or Arruga's forceps. The section was closed by a suture (8-0 virgin silk or monofilament nylon) on either side of the lamellar scleral flap, after inserting the regular flap sutures. The conjunctival flap was closed by a running 6-0 silk suture.

The patients were discharged on the 6th postoperative day and followed up at bi�weekly and then monthly intervals. The average follow-up period was 18 weeks in the gonio trepanation group and 22 weeks in the gonio trepanation-cataract extraction group.

No systemic antibiotics or steroids were used for any of the patients. Topical antib�iotic-steroid drops (Betnesol-N) and homat�ropine or atropine were used postoperatively.

 OBSERVATIONS



The criterion for success in this study was the reduction and maintenance of intraocular pressure below 20 mmHg (applanation). This was achieved in all eyes except one in each group [Table 1]. In the uncontrolled case in the gonio trepanation group, the procedure had been done as a second operation on an eye which had undergone a trabeculectomy and later cataract extraction. The only failure in the second group (combined gonio t�repanation and cataract extraction) occurred in an eye with angle closure glaucoma and an initial tension of 64 mmHg which developed extensive posterior synechiae post-operativ�ely. Thus the overall control of intraocular pressure was 96%.

With two groups combined, 52% of the eyes had their vision remaining stationary and 30% had improved vision. The vision was reduced in only 18% of cases [Table 2]. The main cause for reduction in vision was pro�gressive lens opacities. In the combined pro�cedure group, all the cases which did not show improvement in vision were found to have advanced optic atrophy.

Complications

The important complications encountered during surgery or during the post-operative follow-up are listed in [Table 3]. None of the intra operative or the transient post-oper�ative complication were serious enough to interfere with the final outcome.

The Filtering Bleb

A uniform, smooth and diffuse filtering bleb was present in most cases. It is remark�able that in the cases where the intraocular pressure was not controlled post-operatively, a filtering bleb was absent. Cystic degenera�tion of the bleb was seen in 6 eyes, but in most of them only some parts of the bleb showed a cystic appearance and the wall was not very thin. There was no incidence of breaking down of the bleb or infection.

 DISCUSSION



The introduction of corneoscleral trephin�ing for glaucoma by Elliot in 1909[4] was one of the milestones in ophthalmic surgery, and this operation, with hardly any modification, has been used with highly satisfactory results by many surgeons upto recent times[5],[6]

Trephining, however, had many draw�backs, the most important of which were a shallow anterior chamber and a thin, mul�ticystic bleb, predisposing the eye to the various sequelae of hypotony and also to infection. In the operation for gonio trepana�tion, these problems are redressed by the lamellar scleral flap which covers the trep�hination, thus enabling a controlled drainage and producing a diffuse and uniform bleb. Indeed, the most important innovation in "trabecular" surgery has been the lamellar scleral flap, because it has been proved by many histological studies[7],[8] that trabec�ulectomy and its modifications act as filtering operations, differing from the classical glau�coma filtrations only by the introduction of the scleral flap.

It is noteworthy that with the popularity of trabeculectomy and its modifications the indication for surgery in glaucoma became more liberal, as the complications were found the minimal. It is also generally agreed now that trabecular surgery with cataract extrac�tion does not carry any more risk than a stan�dard cataract extraction[9],[10]

It is to be noted that the results reported after subscleral trephining operations have been consistently better than those after trabeculectomy, 11-20 as a comparison of [Table 4] with [Table 5] shows. The com�plications are also less frequent in gonio t�repanation than in trabeculectomy.[21] In the present series too, the results were excellent and the complication insignificant.

The use of a trephine has certain distinct advantages over a standard trabeculectomy. It enables the surgeon to make a regular and even entry into the anterior chamber and the size of the opening is standardised. The cyclodialysis effect which is often produced in a trabeculectomy by inadvertently opening up the suprachoroidal space is avoided. Trephination is a technically easier and quic�ker method than a conventional trabeculectomy.

 SUMMARY



A prospective study of 50 eyes which underwent subscleral gonio trepanation, alone or in combination with cataract extrac�tion, is presented. The success rate for control of intraocular pressure was 96% and the com�plications were negligible.

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