Purpose:
To investigate the association between empty spaces in the RNFL (Hood et al, IOVS 2011) and the presence, severity, and type of glaucomatous optic discs damage.
Methods:
Circumpapillary OCT scans (Spectralis OCT, 12° [3.5 mm] scan, Heidelberg Engineering, Germany) were reviewed from 103 patients with glaucoma who had focal (n=38, mean MD -7.0 dB), diffuse (n=32, MD -3.7 dB), and sclerotic optic disc damage (n=33, MD -3.7 dB), and from healthy controls (n=106).
Results:
Empty spaces within the RNFL were seen in 24 eyes of 24 (23%) patients, and in 2 eyes of 2 controls (2%, odds ratio, 12.2 [95% CI 2.9, 110], p<0.001). In eyes with glaucoma, spaces were graded as barely visible (8), small (14), and large (2); in controls, barely visible (1) and small (1). Spaces were more commonly seen in the superior (14) and inferior (8) quadrants rather than nasally (2) and temporally (2), and were almost always adjacent to larger vessels (23/26). There was no association between the presence of spaces and subtype of glaucomatous optic disc damage (p=0.51); spaces were seen in 6 eyes with focal damage, in 10 eyes with diffuse, and in 8 eyes with sclerotic damage. There was also no relationship between the presence of spaces and global visual field damage (MD) or RNFL thickness (p>0.35, logistic regression).
Conclusions:
Hypodense "empty spaces" in the RNFL can be seen in circumpapillary OCT scans of patients glaucoma. The aetiology of these spaces, and their proximity to larger vessels, need further investigation.
Keywords: imaging/image analysis: clinical