[Relationship between standard automated perimetry and optic nerve head topography performed with the Heidelberg Retina Tomograph]

PURPOSE

To determine the correlations between optic nerve head (ONH) parameters measured with the Heidelberg Retina Tomograph (HRT), and the main outcomes of standard automated perimetry (SAP) in normal, ocular hypertensive, glaucoma suspects and glaucomatous subjects.

METHODS

Four hundred and twenty-three patients were enrolled in the study and classified into four groups depending on baseline intraocular pressure, optic nerve head morphology, and SAP results: 87 normal eyes, 192 ocular hypertensive eyes, 70 glaucoma suspects and 74 glaucomatous eyes. In the different diagnostic groups, Pearson's correlation coefficients were calculated between ONH parameters and mean deviation, pattern standard deviation (PSD), number of altered points in each quadrant of the visual field (superior-nasal, inferior-nasal, superior-temporal and inferior-temporal), number of points altered at different probability levels, and threshold values at each point of SAP.

RESULTS

In the normal and ocular hypertensive groups, only a few weak correlations were found between HRT and SAP parameters. The strength and number of significant correlations increased in the suspected glaucoma group. The glaucoma group had the strongest correlations, particularly between cup/disc ratio and rim/disc ratio with MD (r=0.479) and between rim area and PSD (r=0.444).

CONCLUSIONS

Weak to moderate correlations were found between some ONH parameters obtained with the HRT and SAP results in the glaucoma group.

[Relationship between standard automated perimetry and retinal nerve fiber layer parameters measured with laser polarimetry]

PURPOSE

To determine the relationship between the structural parameters of the retinal nerve fiber layer (RNFL) obtained by using the scanning laser polarimetry with variable corneal compensation (GDx VCC) and the results of standard automated perimetry (SAP), in normal, ocular hypertensive, preperimetric glaucomas and glaucoma subjects.

METHODS

A total of 423 eyes of 423 consecutive subjects were prospectively included in the study and classified depending on the basal intraocular pressure, optic nerve head appearance and SAP results into four groups: 87 normal eyes, 192 ocular hypertensive eyes, 70 preperimetric glaucomas and 74 glaucomatous eyes. Pearson's correlation coefficients, between mean deviation (MD), pattern standard deviation, number of points altered in each quadrant, and number of points altered at different probability levels of SAP and structural parameters of RNFL obtained by using GDx VCC, were calculated in the different diagnostic groups. In the glaucoma group correlations between the 52 points tested by 24- 2 SITA standard and GDx parameters were also calculated. Regression curves were plotted for the strongest correlations.

RESULTS

Weak or non-significant correlations were found in the normal, ocular hypertensive and preperimetric glaucoma groups. However, the glaucoma group presented weak to moderate correlations between several GDx VCC parameters and the SAP variables analysed. The strongest correlation was observed between the standard deviation TSNIT and the MD (0.460).

CONCLUSIONS

RNFL parameters measured with the GDx VCC presented weak to moderate correlations with the visual field indices and the number of altered points in the glaucoma group.

[Relationship between standard automated perimetry and HRT, OCT and GDx in normal, ocular hypertensive and glaucomatous subjects]

PURPOSE

To determine the correlations between structural parameters of the optic nerve head and the retinal nerve fiber layer (RNFL) obtained by using a Heidelberg Retina Tomograph II (HRT II), optic coherence tomography (OCT), and laser polarimetry (GDX-VCC) and the perimetric indices of standard automated perimetry (SAP) in normal, ocular hypertensive and glaucomatous subjects.

METHODS

Three hundred and eighty-nine patients were enrolled in the study and classified into three separate groups: 43 with normal eyes, 274 with ocular hypertensive eyes and 72 with glaucomatous eyes. Subjects were classified according to the basal intraocular pressure and the SAP results. Pearson's correlation coefficients were calculated between the global perimetric indices, mean deviation (MD) and pattern standard deviation (PSD), and structural parameters of the RNFL and optic disc obtained by using HRT II, OCT and GDX-VCC in the different diagnostic groups.

RESULTS

Mild to moderate correlations were found between the structural parameters measured by HRT, OCT and GDX and the global perimetric indices, in the glaucoma group. Mild or no significant correlations were found in the normal and ocular hypertensive groups. Correlations were stronger for MD than for PSD. Parameters based on the study of the retinal nerve fiber layer showed stronger correlations than those based on the study of the optic nerve head.

CONCLUSIONS

The relationship between structural and functional measurements in glaucoma is weak and therefore the results of these ancillary tests should be interpreted together to increase diagnostic accuracy.