Imaging Of Episcleral Circulation By Confocal Microscopy After Hydrus™ Implant In Glaucomatous Eyes

Abstract

 

Purpose:

 

To investigate the modifications of episcleral circulation by confocal microscopy after implantation of Hydrus™ acqueous shunt in glaucomatous eyes

 

Methods:

 

8 patients received Hydrus™ implant alone or combined with cataract surgery. Imaging of the episcleral circulation was obtained before and 1 week after surgery by confocal microscopy (Heidelberg Retina Tomograph with Rostock cornea module). Images were acquired at 2 mm from the limbus in the planned sector of the device implantation (i.e. for right eyes the supero-nasal quadrant). The HRT acquired images of 400x400 μm at different depths, from the conjunctival surface to the scleral wall. Images were taken in a serial manner both manually and automatically. The depth of the scan was judged taking as landmark the conjunctival epithelium. The images were later evaluated to assess differences between pre- and post-surgery

 

Results:

 

In 3 patients we were able to detect a marked enlargement of episcleral veins (fig. 1 and 2), while in the other 5 we couldn’t see any significative difference. In 5 out of 8 patients we noticed also a reduction of the density of the extracellular matrix. The mean IOP was reduced from 20.4 to 14.4 mmHg

 

Conclusions:

 

Confocal microscopy with HRT showed an enlargement of episcleral veins in some cases after Hydrus™ implant, which is consistent with the supposed mechanism of action of the device. A reduction of the density of the extracellular matrix was also noted in some cases, but the reason of this finding is unclear. The examination using HRT confocal microscopy also showed some limits, mostly related to correcly re-examine the same area and to the high sensitivity at small eye movements. In almost half of the cases no differences were found in episcleral circulation after surgery, despite a succesful reduction in IOP  

 

 

Keywords: microscopy: confocal/tunneling • outflow: trabecular meshwork