Офтальмохирургия (Apr 2017)
MORPHOLOGICAL ANALYSIS OF OUTFLOW PATHWAYS OF AQUEOUS HUMOR AFTER CANALOPLASTY AND NON-PENETRATING DEEP SCLERECTOMY USING OPTICAL COHERENCE TOMOGRAPHY
Abstract
Purpose. To perform a comparative evaluation of dynamics of changes in the natural and surgically formed outflow pathways of aqueous humor using optical coherence tomography (OCT) in patients after canaloplasty and non-penetrating deep sclerectomy (NPDS).Material and methods. The study included 41 patients (66 eyes) with primary open-angle glaucoma of 1-3 stages after the performed surgical intervention. All patients were divided into 2 groups: canaloplasty using the micro-catheter with a 150µm diameter was carried out in 18 patients (32 eyes) in the group 1 and the NPDS without any devices – in 23 patients (34 eyes) in the group 2. All patients underwent standard ophthalmic examinations and the optical coherence tomography of the surgical area was performed on the first day, 1 week, 1 month, 3 months, 6 months, 9 months, 12 months postoperatively. Following features were evaluated: the presence of the filtering bleb and its height, scleral flap thickness, parameters of intra-scleral cavity, presence of inclusions, trabeculodescemet membrane (TDM) size, a hypo-echogenic tunnel behind the scleral flap.Results. Starting from the early postoperative period (up to 7 days) the surgical zone had pronounced differences between the groups. In the main group the filtering bleb height was 0.56±0.16mm while in the control group – 0.98±0.1mm. The initial intra-scleral cavity height was less in the canaloplasty group than in the NPDS group (0.33±0.16mm and 0.59±0.1mm, respectively). The thickness of the scleral flap in the main and control groups was 0.25±0.03 and 0.27±0.03mm, respectively. The average TDM thickness at the baseline was in both groups 0.08±0.002mm.In the long-term period linear dimensions of the investigated parameters of drainage system decreased on the background progressive increase of the optical density of the structures. In the main group 6-12 months after the performed canaloplasty the conjunctiva had practically an intact appearance. Besides, in the group 1 the scleral flap thickness was decreased up to the disappearance the intra-scleral space parameters decreased significantly (0.06±0.025×1.9±0.2×0.42±0.26mm) up to a complete overgrowing. In the control group the filtering bleb height (up to 0.73±0.1mm), the scleral flap thickness (up to 0.12±0.013mm), intrascleral space parameters (up to 0.22±0.12×2.3±0.12×1.7±0.9mm), the hypo-echogenic tunnel behind the scleral flap were decreased. An IOP reduction was detected compared with preoperative levels in all patients. Mean IOP in the canaloplasty group was 21.1±2.1mmHg at 12 months, in the control group – 20.6±2.8mmHg, respectively.Conclusions. The performed comparative analysis revealed a close relationship between structural changes in the area of glaucoma surgery and IOP indices in both groups (a negative correlation of IOP values with the bleb filtering height, scleral flap thickness, height, width and length of the intra-scleral cavity, and a thickness of the trabeculodescemet membrane in the main group, p<0.05). Optical coherence tomography was used to evaluate parameters of the surgical zones after canaloplasty and NPDS.
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