Purpose:
We investigated the mechanism of IOP reduction after trabeculotomy (LOT) using AS-OCT (VisanteTM OCT). We also studied trabeculectomy (TLE) specimens, including the site of previous LOT histologically.
Methods:
In thirty-one eyes of 26 consecutive patients who underwent LOT at Japanese Red Cross Medical Center, outflow routes were examined cross-sectionally by AS-OCT using two different scanning modes (Figure).We also studied histological changes in outflow routes using TLE specimens from 6 eyes with failed LOT.
Results:
The eyes examined by AS-OCT were divided into two groups, group A (successful group); 23 eyes showing more than 20% IOP reduction in pre-op IOP and less than 21mmHg, and group B (failed group); 8 eyes showing less than 20% IOP reduction in pre-op IOP. Empty scleral space (SES) and/or cilio-choroidal detachment (CCD) in groups A and B were observed in 21 eyes (83%) and 3 (38%) eyes, respectively. CCD was not observed in any eyes of group B. All three eyes with SES in group B did not show SES in LOT mode center but SES was observed in LOT mode clockwise or counter clockwise and those findings appeared to show opening of the Schlemm canal (SC) into the anterior chamber (AC).On histological study of TLE, two TLE specimens showed opening of SC into AC.
Conclusions:
Persistent opening of SC into AC on histological examination of TLE and AS-OCT findings of SC opening into AC in the eyes with failed LOT (group B) strongly suggested that IOP reduction by LOT may not depend on surgically opening SC into AC. AS-OCT findings of more frequent SES and CCD existence in the eyes of group A suggests that uveo-scleral outflow in LOT eyes is important.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • pathology: human