Abstract
Purpose: :
To compare parameters measured by different image devices and their accuracy in evaluating postoperative imaging of Schlemm’s canal and grading of suture traction after canaloplasty.
Methods: :
In 24 patients a canaloplasty with interventional canaloplasty microcatheter (iTrack 250A, iScience Interventional, Menlo Park, CA, USA) with viscodilatation and placement of two 10-0 Prolene sutures was performed. Slitlamp adapted OCT (SL-OCT, Heidelberg Engineering, Heidelberg, Germany), 80 MHz ultrasound (iUltraSound, iScience Interventional, Menlo Park, USA) and 40 MHz ultrasound biomicroscopy (VuMax II, Sonomed Inc., NY, USA) was used to visualise Schlemm’s canal and analyze postoperative suture tension grade (0-3) at 3, 9 and 6 o’clock position, suture tension angle and size of trabecular descemet’s window (TDW).
Results: :
We enrolled 12 men and women (mean age: 63.6yrs).17 eyes were treated due to primary open angle glaucoma, 3 eyes because of pseudoexfoliative glaucoma, 3 because of pigment dispersion glaucoma and 1 eye with low tension glaucoma. Mean preoperative IOP without medication was 31.8mmHg (SD 8.2mmHg) and postoperative IOP was 12.1mmHg (SD 3.9mmHg). Mean IOP reduction was 60.9% (SD 11.1%).Morphological evaluation with SL-OCT revealed either a round (n=16) or wedge-shaped (n=8) pattern of Schlemm’s canal. Detailed morphology measured by 80 MHz exhibited 9 shallow filtering blebs, 3 suprachoroidal clefts, 3 possible perforations of TDW and 1 scarred scleral lake.Mean overall suture tension grade was 2.2 (SD 0.6) analyzed by SL-OCT, 1.3 (SD 0.5) by 80 MHz ultrasound and 2.6 (SD 0.3) by 40 MHz. Mean size of TDW was 578 µm (SD 168 µm) measured by SL-OCT, 470µm (SD 272µm) by 80 MHz and 707µm (SD 398µm) by 40MHz.
Conclusions: :
Even SL-OCT and ultrasound devices (80MHz, 40MHz) are based on essentially distinctive technical methods all are eligible for suture tension grading and imaging of morphology of Schlemm's canal after canaloplasty. SL-OCT specifies shape of Schlemm’s canal. 80MHz ultrasound displays highest imaging quality.
Keywords: imaging/image analysis: clinical • trabecular meshwork