Purpose
To investigate the change in the lamina cribrosa (LC) depth following trabeculectomy up to 2 years.
Methods
The study included 28 eyes of 28 primary open angle glaucoma patients who underwent trabeculectomy and followed up for at least 2 years. Serial horizontal B-scan images of the optic nerve head were obtained from each eye using enhanced depth imaging spectral-domain optical coherence tomography. About 65 B-scans covering the optic discs were obtained before surgery, and at 6 months and ≥2 years postoperatively. The pre- and postoperative LC depth (the distance from the Bruch’s membrane opening plane to the level of anterior LC surface) was determined on 7 selected B-scan images in each eye and averaged (mean LC depth).
Results
Intraocular pressure (IOP) decreased from 27.4±9.0 mmHg to 9.7±3.1 mmHg at postoperative 6 months (P<0.001) and then increased to 12.7±5.1 mmHg at mean postoperative follow-up of 27.1±3.3months (P=0.001). The mean LC depth reduced from 625.59±186.33 μm to 499.59±140.56 μm at postoperative 6 months (P<0.001) and then slightly increased to a statistically non-significant level at final follow-up (518.97±133.38 μm). Factors associated with LC depth re-increase were higher IOP at final follow-up (P=0.035), larger IOP fluctuation (P=0.007), higher mean follow-up IOP (P=0.022) and older age (P=0.001).
Conclusions
The LC depth which had been reduced up to postoperative 6 months showed re-displacement in eyes with higher IOP fluctuation, smaller mean LC depth at 6 months and younger age. The data suggest that sustained IOP reduction is essential for preventing re-displacement of the LC after trabeculectomy.
Keywords: 550 imaging/image analysis: clinical •
627 optic disc