|Year : 1967 | Volume
| Issue : 4 | Page : 125-130
Minto Ophthalmic Hospital, Bangalore 2, India
|Date of Web Publication||21-Jan-2008|
Minto Ophthalmic Hospital, Bangalore 2
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sundaresan K. Sclero-iridoencleisis. Indian J Ophthalmol 1967;15:125-30
| Introduction|| |
Corneo-scleral trephining with Elliot's trephine and iridencleisis are two of the most popular operations for glaucoma in India. In South India, trepination has been the preferred operation for quite a few decades. Generally speaking, when the intraocular tension is above 40 mm. Schiotz, trephining is preferred, whereas when the tension is less than 40, iridencleisis is adopted. It is not considered a safe procedure by some surgeons because the iris is deliberately placed under the conjunctiva, which renders it a prey to all inflammatory conditions that may affect the conjunctiva, with the possible supervention of intra-ocular complications.
We therefore thought that if the iris could be protected by a scleral flap and then covered over by the conjunctiva, the vulnerability of the iris might be safeguarded and the results could be more satisfactory. We therefore devised the following modification of iridoencleisis operation.
| Method and Results|| |
The eye is prepared as for trephining with a large conjunctival flap raised by sub-conjunctival infiltration of planocaine-adrenaline. Working from the side of the patient, an incision 10-15 mm, in length is made 6-8 mm. above the limbus and parallel to it. The conjunctiva-Tenon's capsule is dissected from the sclera and up to the limbus. This conjunctival flap is turned down over the cornea. The corneosclera is laid bare with a Tooke's knife, so that a sufficient area around the limbus is made ready for the operation. The reflected flap of conjunctiva is held down by an assistant with the flat of a sterilized toothpick. (Sugar1957). This has the advantage of preventing undue injury and/or buttonholing of the flap.
A scratch incision 6 mm. in length is made along the limbus, nearer the sclera than the cornea.
Another scratch incision 2 mm. in length is made at right angles to the midpoint of the above incision. In most cases, it may be necessary to cauterise a tiny perforating vessel, about 2 mm. above the 12 o'clock position from the limbus, which, if injured is likely to bleed.
A third scratch incision 3 mm. long is made parallel to the first, starting from the upper end of the second incision and towards the left side of it, so that a rectangular area of sclera is marked out ready for dissection [Figure - 1].
With a Hess's iris forceps and a sharp Graefe's knife, the scleral flap is dissected as thin as possible upto the left end of the first incision and replaced in its bed (otherwise the flap retracts considerably, so that later on it may be difficult to use it for covering the iris pillar). [Figure - 2].
The first part of the scratch incision at the limbus is now deepened with a Graefe's knife vertically down towards the anterior chamber. A small quantity of aqueous trickles out from some point along this incision, denoting that the anterior chamber is reached. One should wait until the aqueous stops flowing out and then deepen the incision throughout the 6 mm. length.
The heel of the iris forceps is gently pressed on the scleral side of the incision, when the iris protrudes through the section. It is now held with the same iris forceps and drawn out until the margin of the pupil is visualized. [Figure - 3].
The mass of iris thus held is lifted so that it is held vertically upwards, and the right hand end is cut sharply with a DeWecker's scissors radially upto the pupil. The free coloboma pillar thus released gets back into the eye. With deWecker's scissors, the iris is then cut along its root until an iridodialysis is made up to 2 mm. from the left end of the section.
A fairly long piece of iris is now held in the iris forceps [Figure - 4]. This piece of iris will be either thick and fleshy or thin and friable. The latter condition is common when there is advanced atrophy of the iris due to glaucoma and, as Sugar (1962) aptly observes, the iris pigment "melts away like chocolate" during this manipulation. The former condition of the iris is seen in the earlier phase, i.e. the hypertrophic phase. The hypertrophic iris does not shed its pigment as the atrophic iris does.
The cut iris; limb held in the forceps is gently but firmly drawn tight into the left hand corner of the section and laid on the sclera. The scleral flap which was prepared in step 2 is lifted out of its bed, placed over the iris tag and tapped into position [Figure - 5]. The extra length of the iris tag is snipped off just above the scleral flap.
The conjunctiva-Tenon's capsule flap held down by the assistant is now lifted and stitched to its normal position with a continuous suture.
On the following day, the conjunctiva in this area is chemosed, and as the treatment progresses the chemosis gets localized around the flap so as to form a nice bleb in the operated area at the time of the patient's discharge. The scleral flap, through which one may see the iris, appears brick red in colour in the early stages and later becomes white in colour and spongy in texture [Figure - 6]. The tension generally remains between 16 and 22 mm. at the time of discharge (8 days) and that level is satisfactorily maintained. We have not come across iritis, iridocyclitis or endophthalmitis in any of the cases.
We began this operation in absolute glaucoma cases, to get wise about all possible complications in such a procedure; but no catastrophe of any kind occurred in any case. On the contrary, the filtering scar was quite nicely formed with an intraocular tension maintained between 16 and 22 mm. (Before the operation, the absolute glaucoma cases had a tension of 70-90 mm. Schiotz).
We have been able to follow up only ten cases of the 40 operated upon and have found that all of them maintained a steady intra-ocular tension between 16 and 22 mm. Schiotz's, ranging from one to five years' follow up after the operation.
Case 1: Mr. S. Rao has been under observation for the last five years. The right eye had sclero-iridencleisis done for absolute glaucoma. Tension has been 18 mm upto January 1966.
Case 2: Mrs. N Right eye had sclero-iridencleisis done for absolute glaucoma. The left eye, trephined for closed angle glaucoma, is maintaining 6/24 vision with glasses. In this case, the bleb formed by the trepination and our operation are well formed, have a spongy appearance, and are indistinguishable from each other but for the fact that in the trephined eye we made peripheral-iridectomy which distinguishes it from the coloboma of our operation.
Case 3: Mr. M Absolute glaucoma in the right eye with 70 mm. before operation and 22 mm. subsequently. He has been seen regularly for four years.
Case 4: Mrs. G. Baomi, (40 years) closed angle glaucoma; vision with glasses 6/9 before operation. Sciero-iridencleisis done two years ago. A well formed bleb is seen; tension 20.0 mm maintained; vision 6/9 maintained.
Case 5: Mr. V Right eye trepanation (1966) vision 6/6 before and after operation. Left eye sclero-iridencleisis (1966) vision 6/18 before and 6/9 after operation. Before operation tension was 40 mm. Schiotz's in each eye-after operation R.E. 18 mm. L.E. 16 mm. maintained up-todate. He is 37 years old.
A break up of the cases done between 1962-1966 is as follows:
Sclero-iridencleisis .. 40 cases
Elliot's Trephining .. 85 cases
Iridectomy .. 77 cases
Iridencleisis .. 18 cases
Cyclo-dialysis ..4 cases
Total - 224 cases
In this series, men were found to be more prone to glaucoma than women in the ratio 7:3. Out of 40 cases, 28 were men and 12 women.
Age incidence of glaucoma patients on whom sclero-iridencleisis was done
21-30 .. 2 cases
31-40 .. 1 cases
41-50 .. 6 cases
51-60 .. 9 cases
61-70 .. 16 cases
70 and above .. 6 cases
Number of sclero-iridencleisis operations done between 1962 and 1965.
1962 .. 11 cases
1963 .. 15 cases
1964 .. 8 cases
1965-66 .. 6 cases
| Discussion|| |
For iridoencleisis it is preferable to make a perpendicular incision than a shelving one because, as pointed out by Sugar (1962), in the latter instance the edges of the wound are postero-superior and antero-inferior [Figure - 7] which tend to get opposed to each other by the intra ocular pressure (10P) and thus narrows down the filtration passage. This would not happen if the wound edges are posterior and anterior as in a perpendicular incision [Figure - 8] where the edges would tend to open out under 10P and promote filtration.
This filtration is further helped by tucking the iris in the ends of the incision, and making the deeper part of the cut as long as the superficial part -Sugar (1962).
The work of S. Vannas and H. Tier (1960) on the histopathology of the drainage region of the sclera in glaucomatous eyes shows that the collagen fibres are atrophic, although the scleral structure is mainly closely knit. Some empty pores are seen near the exit veins. According to Vannas and Tier, "This was rather surprising finding in glaucomatous eyes in view of the fact that these eyes usually have an increased resistance to outflow; it could contradict the significance of the sclera as a barrier to outflow." Their work shows that in simple glaucoma there are so-called tubular structures running perpendicular to the meridional collagen bundles. But these are rather sparce in extent; while in closed angle glaucoma, the unusual bundles mentioned above are abundant before and behind Schlemm's canal. At the level of the ora serrata and behind it, no variations from control eyes were found. Well formed blebs were noted in closed angle glaucoma cases, whilst the blebs were flattened in the openangle cases. It may be that the abundance of the unusual bundles in closed angle glaucoma contributes to the formation of the bleb and possibly to the spongy change of the scleral flap.
Gyula Lugossy (1960) has reviewed the work of Laval who applied an absorbable gelfilm into the scleral wound, which enabled the formation of a large filtration scar. In our operation the scleral flap serves the same purpose, but is ideal in that it is homologus tissue, which in addition retains its nutritional supply. In Lugossy's modified operation no gelfilm is used, but he lays stress on the correct placement of the iris, flap with its under surface carefully and neatly spread on the sclera and the incision made 2 mm. above the limbus and 8 mm. in length. This operation has also been shown to produce a rather large filtering bleb. The work of DeWeckers reveals that the tension-lowering effect is irrespective of the length of the incision and that a large bleb may lower the tension to 12 or even 9 mm. In none of our cases was the tension lower than 16 mm, The above workers contend that after an iridencleisis there is a complex neuro-vascular change taking place at the level of the anterior uvea, which could be responsible for maintaining the lowered intra-ocular pressure.
| Summary and Conclusion|| |
A new modification of iridencleisis for glaucoma, viz: sclero-iridencleisis, is described. Uniformly good results have been obtained by adopting this operation in all cases of glaucoma, irrespective of whether they are open or closed angle. An additional step of making a scleral flap to protect the iris and maintain a filtration passage takes just three minutes more.
In our cases the intra-ocular pressure after the operation fell to about 18 mm. as measured on the eighth day of the operation and was found maintained between 16-22 mm, in those cases that could be followed up for 1 to 5 years.
Inflammatory reaction and cataract formation, were not met with in any of the follow-up cases. The 6 mm. long incision at the limbus, the vertical penetration into the anterior chamber and the transected limb of the iris ensured a regular coloboma pedicle free from scar formation. Tucking of the iris pedicle under the thin scleral flap resulted in a well-formed filtering bleb which persisted and showed promise of remaining so permanently in all closed angle glaucoma cases.
The operation was done as a preliminary study on absolute glaucoma cases for about two years. With gratifying results, this procedure has been adopted by us routively for all cases of chronic glaucoma.
| Acknowledgments|| |
I would like to thank Dr. S. T. Puttanna, Vice-Dean of the Minto Ophthalmic Hospital, Bangalore, for his helpful comments and to U. B. S. Prakash for figures one to six.
| References|| |
Sugar, H. S.: The Glaucomas. St. Louis, C. V. Mosby Co., 1957 Ed. 2.
Sugar, H. S.: (1962). Amer. J. Ophthal., 54, 917-929.
Vannas, S., and Tier, H. (1960) Amer. J. Ophthal. 49: 411-416.
Lugossy, G. (1960) Amer. J. Ophthal., 49: 1369-1380.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]