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EDITORIAL |
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| Year : 1993 | Volume
: 41
| Issue : 2 | Page : 49 |
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Glaucoma surgery : New approaches
NN Sood
India,
Correspondence Address:
N N Sood
India
PMID: 8262603
How to cite this article:
Sood N N. Glaucoma surgery : New approaches. Indian J Ophthalmol 1993;41:49 |
The practice of glaucoma in developing countries is attended with the problem of lack of available statistics on prevalence rates, types of glaucoma and follow-up studies of treatment modalities. The current issue of the journal addresses itself to some of these questions. The long-term results of trabeculectomy in primary open-angle glaucoma, in Indian Eyes have not been satisfactory. Not unlike the counterparts elsewhere in the world, in the high risk groups (juvenile age group, glaucoma in aphakia, neovascular glaucoma, glaucoma in uveitis and failed surgeries), [1] the results of standard trabeculectomy are poor. The use of antimetabolites such as 5-Fluorouracil, Mitomycin C and Daunorubicin, (which inhibit the proliferation of cultured fibroblasts) have improved results of surgery in these groups. The paper by Khan et al, substantiates the efficacy of 5-Fluorouracil in Indian Eyes. The authors found corneal erosions (38%) wound leaks (16%) subconjunctival hemorrhage (32%) and hyphaema (10%) as complications. Frank et al, have also documented hypotony with or without maculopathy and Dellen, [2] 5-Fluorouracil blebs also tend to be thin, cystic and more prone to leakages and injection. The need for repeated injections increases the convalescent period and makes their use not very suitable for children. At the end of two year period only 5.3% of 5-FU group needed medical control as compared to 40% controls, in uncomplicated cases.
Mitomycin C on the other hand is used as single intraoperative dose and hence more convenient. The mitomycin blebs tend to be thin, diffuse and avascular. An intraocular pressure of less than 20mm Hg without medications is achieved in 88% eyes treated with Mitomycin C compared with 47% of the eyes treated with 5-FU. [4] The risk of corneal complications is less with Mitomycin. Single dose application makes its use suitable for children. Trials are also going on for its use in glaucoma amongst new born. A 3% incidence of hypotony maculopathy has been described with Mitomycin C. [5] 5-FU may still be used, whenever it is needed in the post operative period (Holimium laser sclerostomy, early post operative fibrosis of standard trabeculectomy).
In any surgery with antimetabolite usage, it is essential to make a limbus based flap and meticulously suture the scleral flap and conjunctiva. Another modification in the technique of trabeculectomy to increase filtration is the use of releasable sutures with or without Mitomycin C. Jacob et al, in this issue emphasize the need to delay the release of sutures upto two weeks wherever antimetabolites have been used. Hypotony may develop after suture cutting six weeks after surgery and care should be taken while releasing trabeculectomy flap suture. [5]
The antimetobolites have no doubt improved the results of trabeculectomy but one should be aware of the attendant risks. In view of this it is desirable (until more long term results are available) that the use of Mitomycin should be restricted to cases with poor surgical prognosis or where a single digit I.O.P is desired . [5] Additional or releasable sutures may be preferable and release of these sutures should be delayed. The use of this drug should be avoided in cases with decreased scleral rigidity (young myopes).
A continued scrutiny of complications that accompany the improvement in results of filtration surgery with employment of antimetabolites is essential.
 References | |  |
| 1. | Sood N N, Harsh Kumar, Aggarwal H C, Sihota R: Role of 5 Fluorouracil in management of failed Glaucoma surgery. Ind J Ophthalmol., 38: 17-19, 1990.  |
| 2. | Frank W A, Hitchings R A. Complications of 5 Fluorourcacil after trabeculectomy. Eye. 5: 385-389, 1991. |
| 3. | Lieman J M, Ritch R, Marmor M. et al. Inititial 5 Fluorouracil. Trabeculectomy in uncomplicated glaucoma. Ophthalmology. 98: 1036-1041, 1991. |
| 4. | Kitazawa Y, Kawase K, Matsushista H and Minobe M. Trabeculectomy with Mitomycin C: A comparitive study with Fluorouracil. Arch Ophthalmol, 109: 1093-1698, 1991. |
| 5. | Costa V P, Wilson R P, Moste M R, Schmidt C M, Gandham, S.Hypotony maculopathy following use of Topical Mitomycin C in Glaucoma Filtering Surgery, Ophthalmic Surgery 24: 389-393, 1993. |
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