Artikel
How does viscocanalostomy work? : a new concept to the mode of action using scanning electron microscopy
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Veröffentlicht: | 22. September 2004 |
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Gliederung
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Objective
Several studies have proven the efficacy of viscocanalostomy as a non-penetrating approach in glaucoma surgery. The mechanism responsible for the decrease in intraocular pressure has not been clarified in detail.
Patients and methods: From a pool of over 200 patients having undergone standardized viscocanalostomy performed by one surgeon 50 eyes were selected for this study. 25 eyes were defined as a long-term success, whereas in 25 eyes, a repeat operation was necessary. The resected deep scleral flap was investigated using scanning electron microscopy. Morphological findings were correlated with the clinical outcome.
Results
In 45 scleral flaps (90%), tissue of Schlemm's canal was found. Absence of Schlemm's canal correlated with early postoperative failure (p<0.05). The amount of anterior trabecular meshwork correlated well with the long-term success (p<0.01). The number of septae in Schlemm's canal showed a significant coherence to the incidence of postoperative hypotony (p<0.001), whereas there was no correlation to the success rate.
Conclusions
Schlemm's canal was precisely deroofed in most of the cases. A deep sclerectomy without resection of anterior meshwork seems to have a lower effect on reduction of IOP. A microperforation of the inner wall of Schlemm's canal due to resection of septae leads to a higher risk of early postoperative hypotony, but has no influence on long-term results.