Abstract
Purpose: :
What is the filtering surgery architecture of success or failure as observed with high resolution ultrasound biomicroscopy (HR-UBM) in both trabeculectomy or deep sclerectomy? Does this technique provide enough definition and penetration to draw a comprehensive image of the intra-ocular pressure (IOP) modifications mechanisms?
Methods: :
A prospective HR-UBM study on 93 eyes (68 patients) who underwent filtering surgery (trabeculectomy or non penetrating deep sclerectomy, NPDS). This was done at an average 18±11 months after the operation. The anterior segment of the eye in the surgical area was screened with a 25MHz ultrasonography probe (Atys Medical®, France) to determine the IOP modifications anatomical supports. The ultrasound features were then compared with the clinical exam (IOP slit lamp appearance of the blebs). IOP Target in our study was 21 mmHg.
Results: :
At the examination time 58 patients were group 1 (IOP target achieved without treatment), 20 patients were group 2 (IOP target achieved with treatment), 16 were group 3 (IOP target not achieved). No statistical difference between trabeculectomy and NPDS with a HR-UBM evaluation. In 23 trabeculectomies and 15 NPDSs, HR-UBM success criteria (group 1 and 2) were : hyporeflectivity, bleb elevation, visible drainage channels and a hypoechogenic supra-choroïdal space (100- 250 microns high). A statistical relationship was found between these four criteria (p=0.02) and a diffuse subconjunctival filtration (slit lamp).
Conclusions: :
A clear anatomical picture of all aqueous pathways in filtering surgery is provided by HR-UBM. Similar aspects were noted in trabeculectomy and deep sclerectomy. Detection of failure criteria at a reversible stage of wound healing might improve filtering surgery prognosis.
Keywords: imaging/image analysis: clinical • intraocular pressure • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)