Year : 1992 | Volume
: 40 | Issue : 2 | Page : 41--43
Comparative results of limbal based versus fornix based conjunctival flaps for trabeculectomy
AM Khan, FA Jilani
Institute of Ophthalmology, A.M.U., Aligarh, India
A M Khan
Institute of Ophthalmology, A.M.U., Aligarh
Among 100 cases of primary glaucomas, 50 cases were operated for trabeculectomy by making fornix based flap and 50 cases were operated by fashioning limbal based conjunctival flap. Operative and post operative complications were studied thoroughly in the two groups. All the cases were followed up for six months to one year to assess control of intra ocular pressure, nature and functioning of filtering bleb, field changes and visual status in the two groups. It was found that the fornix based flap is much superior and carries various advantages over the limbal based flap. The operative and post operative complications are minimum in the fornix based flap as compared to the limbal based flap.
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Khan A M, Jilani F A. Comparative results of limbal based versus fornix based conjunctival flaps for trabeculectomy.Indian J Ophthalmol 1992;40:41-43
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Khan A M, Jilani F A. Comparative results of limbal based versus fornix based conjunctival flaps for trabeculectomy. Indian J Ophthalmol [serial online] 1992 [cited 2024 Mar 3 ];40:41-43
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For performing trabeculectomy the conjunctival flap is fashioned either limbal based or fornix based. It is however, generally observed that the fornix based flap is more superior, easy to fashion, and lesser complications as compared to the limbal based flap. A comparative study was, therefore conducted by operating 100 cases of primary glaucomas The limbal based conjunctival flap was made in 50 cases and the fornix based flap in the other 50 cases. Various complications during surgery and post opera�tively in the two groups were observed. The cases were followed for six months to one year to assess the effectiveness of the procedure in the two groups.
MATERIAL AND METHODS
For the present study 100 diagnosed cases of primary glaucomas were selected. 65 cases of primary narrow angle glaucoma and 35 cases of open angle glaucoma were thoroughly investigated. All the cases of narrow angle glaucoma in this study were the cases which were brought in a stage of acute congestive or chronic congestive glaucoma. Those cases of open angle glaucoma were included in this study in whom intra ocular pressure was not controlled by maximum medical therapy or the compliance to medical treat�ment was poor.
Refraction undilated, applanation and Schiotz tonometry, gonioscopy, central and peripheral fields recording and slit lamp examination was done in all cases. Fundus examination was done to assess cup disc ratio. All the cases were admitted in the hospital prior to surgery and I.O.P was controlled by medical treatment, after which trabeculectomy was performed. Conjunctival flap was fashioned as limbal based in 50% cases and fornix based in the other 50% cases. Various complications during surgery and post opera�tively were carefully recorded in each case. Follow up was done at one month, three months, six months and at one year. Vision, central fields, slit lamp examination and I.O.P were recorded at each visit.
In this study 100 cases of primary glaucomas were investigated and subjected to surgery. The cases were divided in two groups. Group A included 35 cases of primary narrow angle glaucoma and 15 cases of open angle glaucoma, whereas group B included 30 cases of narrow angle glaucoma and 20 cases of open angle glaucoma. The age and sex distribution of cases in the two groups is shown in table sub . After control of I.O.PP all the cases were operated for trabeculectomy. In group A cases, limbal based conjunctival flap was fashioned while in group B cases, fornix based flap was designed. Various early and late complications in the two groups are shown in [Table 2][Table 3].
As shown in [Table 2] button holing of the conjunctiva did not occur in a single case of fornix based flaps as compared to 5 cases (10%) in [tie limbal based flap. Retraction of conjunctiva post operatively and prolonged shallow anterior chambers were seen in the limbal based flaps. Similarly hypertrophy of the bleb was noticed at 3 months follow up in the 3 cases (6%) of limbal based flaps [Table 3]. Large number of patients in this group, 12 cases (24%), required further medical treatment post operatively to keep I.O.P controlled as compared to 4 cases (8%) in the fornix based flaps.
The fornix based flap has many advantages over the limbal based flap. Fornix based flap is a con�junctiva-tenon's flap. Tenon's capsule is adherent to the conjunctiva at the external posterior border of the limbos. Thus both the layers are dissected from the limbus as a single flap. Tenon's capsule will scar at the limbus when replaced and not within the bleb as occurs with a limbal based flap. There is better exposure for dissection of the scleral flap well into the corner. This ensures a trabeculectomy in front of the root of the iris and ciliary body and prevents obstruction of the trabeculectomy opening by hypertrophic ciliary pigment or iris adhesions sub The procedure is technically easier than dissecting a limbal based flap especially in cases of scarred conjunctiva. due to previous surgery or trauma. Pos�sibility of damaging the conjunctival flap during dis�section, especially button holing of the flap is eliminated. Thus in this study none of the 50 cases operated with fornix based flap had any button hole as compared to the 5 cases(10%) among limbal based flaps.
The conjunctival flap adheres and scars at the limbus. The bleb that results is posteriorly placed, diffuse, well vascularized and thick walled, extending towards the upper fornix. There is little possibility of developing a thin, avascular. hypertrophic bleb overhanging the cornea ,. sub In this study such hypertrophic, blebs were .noticed postoperatively in 3 cases (6%) in limbal based flaps, while none in fornix based flaps.
The risk of a shallow or absent anterior chamber post operatively is considerably reduced in fornix based flaps. In this study post operative shallow anterior chamber was found in 10 cases (20%) in limbal based flaps as compared to 3 cases (6%) in fornix based flap. Post operative control of I.O.P was much better in fornix based flaps. At three and six months follow up. 12 cases (24%) in limbal based flaps required additional medication for control of I.O.P as compared to 4 cases (6%) in fornix based flaps. Similarly soft and hard contact lenses can be fitted within two weeks after surgery in fornix based flaps as the bleb is posteriorly placed and there is a line of scar tissue at the limbos .
Thus, to get better results of trabeculectomy to achieve prolonged control of I.O.P, well vascularized, thick-walled posteriorly placed bleb with minimum chances of button holing of the conjunctiva and prolong shallow anterior chamber post operatively, a fornix based flap should be fashioned for trabeculec�tomy.
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|Odeh. N.N. A new fornix based flap for trabeculectomy international Congress Medica, Amsterdam 1978.
|Luntz M.H. trabeculectomy using a fornix based conjunctival flap and tightly sutured scleral flap 87 (10)985-989. 1980.
|Luntz. M.H. and freedman J. The fornix based conjunctival flap for glaucoma filtering surgery Ophthal Sur.11(8) 516. 1980.