Purpose:
To assess topographic optic disc changes following successful trabeculectomy in adults with open angle glaucoma (OAG).
Methods:
Optic discs of OAG patients were scanned within a week before trabeculectomy, then one week, one month and one year postoperatively. Radial scans of the optic disc were performed with Spectralis OCT. The AutoRescan algorithm was used to place the postoperative scans at the same location of the baseline scan. Images were then exported to the Adobe Photoshop platform where a reference line was manually drawn between the edges of the optic disc. Length of reference line indicating disc diameter (DD), maximal (MCD) and average (ACD) cup depths were automatically calculated by the software. Pre- and postoperative measurements of DD, MCD and ACD were compared. Pre-study reproducibility measurements indicated good inter-observer agreement in DD measurements (1.7 μm, 95% CI: -23.7 to 27.0).
Results:
22 eyes of 20 OAG patients (66.5±10.6 years, mean MD: -15±9.8 dB) completed the 1-year follow-up. Mean intraocular pressure (IOP) decreased from 22.7±4.0 mmHg preoperatively to 11.5±2.6 mmHg at 1-year follow-up (p=0.0001). Preoperative DD measurements were similar to postoperative DD values at all follow-up visits. Compared to preoperative values, there was a significant postoperative ACD decrease at 1 week (p=0.0001) and 1 month (p=0.001), but not at 1 year (p=0.059). Similarly, there was a significant postoperative MCD decrease at 1 week (p=0.027) and 1 month (p=0.005), but not at 1 year (p=0.635).
Conclusions:
IOP reduction in advanced OAG after successful trabeculectomy induces topographic optic disc changes that become less pronounced over time; these changes are not detectable at 1-year follow-up.