Session Title: Quick Fire Free Paper 5
Session Date/Time: Sunday 14/09/2014 | 11:00-13:00
Paper Time: 11:15
Venue: Boulevard B
First Author: : S.Batta Arora INDIA
Co Author(s): : S. Batta N. Goel A. Seth G. Bhushan U. Raina B. Ghosh
To evaluate retinal nerve fibre layer (RNFL) thickness after brilliant blue (BB) assisted internal limiting membrane (ILM) peeling in macular hole (MH) surgery.
Prospective interventional case series carried out between January 2011 to January 2013.
Thirty eyes of 30 patients with stage 2-4 of idiopathic MH with a clear media and no history of glaucoma or any other disease that could affect RNFL measurements ( i.e. optic nerve atrophy ) were included. Patients underwent pars plana vitrectomy, BB assisted ILM peeling and sulphur hexafluoride gas tamponade. Clinical examination, fundus photograph and spectral domain optical coherence tomography (SD-OCT) was done preoperatively and at 3 weeks, 6 weeks, 16 weeks and 6 months postoperatively. Peripapillary RNFL thickness was evaluated at a calculated 3.45 mm diameter around the centre of the disc. Mean total, mean temporal and mean nasal RNFL thickness were assessed.
Mean total RNFL thickness was 103.3 ± 5.9 µ preoperatively, 101.54 ± 7.5 µ at 3 weeks (p= 0.1), 95.05 ± 9.92 µ at 6 weeks (p < 0.001), 90.61 ± 5.6 µ at 16 weeks (p < 0.001), 91.8 ± 8 µ at 6 months (p < 0.001) and the decrease was highly significant 6 weeks onwards. Mean temporal RNFL thickness was 75.2 ± 7.8 µ preoperatively and was significantly decreased at all postoperative visits. It was 70 ± 7.9 µ at 3 weeks (p < 0.001), 63.7 ± 8.4 µ at 6 weeks (p < 0.001), 61.5 ± 9.5 µ at 16 weeks (p < 0.001) and 57.6 ± 6.3 µ at 6 months (p < 0.001). Mean nasal RNFL thickness was 77.5 ± 13.3 µ preoperatively and it did not change significantly postoperatively (79 ± 12.8 µ, p= 0.24 at 3 weeks; 78.2 ± 19.1 µ, p = 0.4 at 6 weeks; 73.9 ± 12.9 µ, p = 0.1 at 16 weeks and 73.3 ± 12.7 µ, p = 0.08 at 6 months).
BB dye causes reduction of RNFL thickness. Because the ILM is thickest at the posterior pole of fundus, a high concentration of BB might remain within the ILM in the posterior pole except in the macular region where ILM was removed during surgery. The retained BB might be distributed over the inner retina and then transported towards the optic disc causing reduction of RNFL thickness. Since the dye is injected over the macular area during the surgery, its concentration is expected to be higher temporal to the disc which may explain loss of RNFL thickness temporally and not nasally.