Optic nerve sheath diameter in normal-tension glaucoma patients
- Gregor Peter Jaggi1,
- Neil Richard Miller2,
- Josef Flammer3,
- Robert N Weinreb4,
- Luca Remonda5,
- Hanspeter Esriel Killer1,3
- 1Department of Ophthalmology, Kantonsspital Aarau, Switzerland
- 2Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA
- 3University of Basel, Eye Institute, Switzerland
- 4Department of Ophthalmology, Hamilton Glaucoma Center, University of California, San Diego, California, USA
- 5Department of Neuroradiology, Kantonsspital Aarau, Switzerland
- Correspondence to Professor Dr.med. Hanspeter Esriel Killer, Kantonsspital Aarau, Buchserstrasse, CH-5001 Aarau, Switzerland;
- Accepted 30 January 2011
- Published Online First 11 March 2011
Background To report on the optic nerve sheath diameter (ONSD) in patients with normal-tension glaucoma (NTG) compared with controls without known optic nerve (ON) or intracranial disease.
Methods In 18 patients with NTG (mean age 64.9±8.9 years; 7 women and 11 men), CT of the orbit was performed. 17 age- and gender-matched patients without ON or intracranial disease, who underwent CT of the orbits for non-ophthalmological reasons, served as controls. The widest intraorbital ONSD in axial sections was measured using a standardised technique. Study design: unmasked. Statistical analysis was performed using an independent two-tailed t Test and the non-parametric Spearman correlation test.
Results ONSD was significantly (p<0.001) increased in NTG patients (right side: mean 7.9±0.9 mm SD; left: 8.0±1.1 mm) compared with controls (right: 6.3±0.5 mm; left: 6.1±0.6 mm). Neither the NTG nor the control group had a significant difference in ONSD between males and females or between right and left sides.
Conclusions An increased ONSD is generally associated with increased intracranial pressure; however, ONSDs in a group of NTG patients also were significantly increased compared with controls. ON sheath compartmentation and thinning of the ON sheath are two possible explanations for an increase in the ONSD in patients with NTG.
Competing interests None.
Ethics approval This study was conducted with the approval of the Kantonale Ethikkommission Aargau—this study is part of the ‘Normal Tension and Chronic Open Angle Glaucoma and Cerebrospinal Fluid Composition’.
Provenance and peer review Not commissioned; externally peer reviewed.