Clinical Guidelines prev next

Jun 21 2006

More CCT

posted by: Bud O'Leary, OD

An interesting retrospective study by H. Choi, MD, M, Dong, MD and S. Hwang, MD published in the Journal of Glaucoma, April 2006, addresses the importance of CCT as a predictor of localized RNLF defects at initial evaluation for NTG.

As we know, the importance of CCT in the ocular hypertensive progression to POAG has been established in OHTS. CCT also has been shown to be predictive of the severity of damage in POAG. However, the role of CCT as a predictor of progression or severity in NTG has been lacking.

In this study, data from 75 patients demonstrating localized RNFL defect and corresponding visual field defect upon initial NTG evaluation were reviewed. The mean CCT in the study was 520 μm, which the authors report as significantly thinner than the normal Korean population (530μm). Multivariate analysis indicated that decreased CCT was significantly associated with increased cup to disc ratio (both horizontal and vertical) and localized RNFL defect.

The study suggests that decreased CCT is a significant factor in prediction of structural damage at the initial examination for NTG. However, decreased CCT was not found to be a significant predictor of functional damage using HFA 30-2, MD.

This study clearly related the significance of decreased CCT to RNFL defect and c/d ratios in NTG. The implication of CCT to functional status needs further investigation.

As the authors note, this study reflects data from an initial examination and does not provide data regarding progression of damage in NTG.