Abstract
Purpose: :
To investigate the relationship between retinal light sensitivity measured with standard automated perimetry (SAP) and peripapillary retinal nerve fiber layer (RNFL) thickness measured with the Stratus OCT.
Methods: :
One hundred forty healthy subjects and 66 patients with glaucoma (IOP > 22 mmHg, GHT and CPSD "outside normal limits") were examined with SAP and with the Fast RNFL Thickness examination of the commercially available Stratus OCT. Visual field examination was performed by the 24/II program of the Humphrey Field Analyzer, and the OCT results were analyzed by means of the RNFL Thickness Average analysis. Individual visual field test points and peripapillary RNFL thickness measurements were grouped into 6 topographically corresponding sectors, according to Garway–Heath et al (2000). The correlation between perimetry and OCT measurements was determined, and the relationship between RNFL thickness and perimetry, expressed both in the standard decibel scale and in an unlogged scale, was described with linear and quadratic regression analysis.
Results: :
The equation that better explained the model was curvilinear when using the Decibel scale, and tended to become linear when using the Unlogged scale. A statistically significant correlation between perimetry and OCT measurements in patients with glaucoma was found in most sectors both using the Decibel (quadratic regression analysis r2 ranging between 0.19 and 0.51, P<0.001), and the Unlogged scale (quadratic regression analysis r2 ranging between 0.17 and 0.45, P<0.001). No meaningful correlation was found in healthy subjects (quadratic regression analysis r2 < 0.1).
Conclusions: :
OCT measurements of the peripapillary RNFL relate well with functional loss in glaucoma with both Decibel and Unlogged scales. Since a Decibel scale is provided by Visual Field analyzers, patients with mild to moderate visual field loss in glaucoma may be better monitored with the OCT as compared to patients with severe loss, who may be better monitored with SAP.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • perimetry