Objective: To assess retinal nerve fiber (RNFL) thickness change in glaucoma patients after glaucoma surgery.
Material and Method: A prospective and cohort study of 19 patients who underwent trabeculectomy with mitomicin C or combined procedures or glaucoma drainage device surgery in Phramongkutklao Hospital were included. All subjects had obtained informed consents. Preoperative and 3 month-postoperative IOP and RNFL thickness were determined. Areas of peripapilllary RNFL thickness were evaluated by Stratus OCT scanning. The relationship between IOP reduction and RNFL thickness change after glaucoma surgery was analyzed.
Results: Postoperative RNFL thickness analysis found no significant increase in inferior, superior, nasal and temporal quadrants. The average of preoperative RNFL thickness was 59.58 + 17.59 microns, whereas the average of postoperative RNFL thickness was 57.19 + 14.97 microns (p = 0.426). Postoperative IOP was decreased significantly from 29.26 + 8.58 mmHg to 12.11 + 4.52 mmHq (p < 0.001). The mean of postoperative RNFL thickness was not significantly correlated with IOP reduction (r = 0.306, p = 0.250).
Conclusion: Post glaucoma surgery, RNFL thickness was not significantly increased although the IOP had significantly reduced. No correlation between IOP reduction and RNFL thickness was found.

Keywords: Optical coherence topography (OCT), Retinal nerve fiber layer thickness (RNFL), Intraocular pressure (IOP)