Structure–Function Correlations Using Scanning Laser Polarimetry in Primary Angle-Closure Glaucoma and Primary Open-Angle Glaucoma
Accepted 1 December 2009. published online 04 March 2010.
Purpose
To assess the correlations between retinal nerve fiber layer (RNFL) thickness measured with scanning laser polarimetry and visual field (VF) sensitivity in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).
Fifty patients with POAG and 56 patients with PACG were examined using scanning laser polarimetry with variable corneal compensation (GDx VCC; Laser Diagnostic Technologies, Inc.) and Humphrey VF analyzer (Carl Zeiss Meditec, Inc.) between August 2005 and July 2006 at Taipei Veterans General Hospital. Correlations between RNFL thickness and VF sensitivity, expressed as mean sensitivity in both decibel and 1/Lambert scales, were estimated by the Spearman rank correlation coefficient (rs) and multivariate median regression models (pseudo R2). The correlations were determined globally and for 6 RNFL sectors and their corresponding VF regions.
Results
The correlation between RNFL thickness and mean sensitivity (in decibels) was weaker in the PACG group (rs = 0.38; P = .004; pseudo R2 = 0.17) than in the POAG group (rs = 0.51; P < .001; pseudo R2 = .31), but the difference in the magnitude of correlation was not significant (P = .42). With Bonferroni correction, the structure–function correlation was significant in the superotemporal (rs = 0.62), superonasal (rs = 0.56), inferonasal (rs = 0.53), and inferotemporal (rs = 0.50) sectors in the POAG group (all P < .001), whereas it was significant only in the superotemporal (rs = 0.53) and inferotemporal (rs = 0.48) sectors in the PACG group (both P < .001). The results were similar when mean sensitivity was expressed as 1/Lambert scale.
Conclusions
Both POAG and PACG eyes had moderate structure–function correlations using scanning laser polarimetry. Compared with eyes with POAG, fewer RNFL sectors have significant structure–function correlations in eyes with PACG.
aDepartment of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
bNational Yang Ming University School of Medicine, Taipei, Taiwan
cInherited Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, Maryland
dDepartment of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
Inquiries to Ching-Yu Cheng, Department of Ophthalmology, Taipei Veterans General Hospital, 201 Shih-Pai Road Section 2, Taipei, Taiwan
ABSTRACT