Abstract
Purpose: :
to determine the diagnostic accuracy (DA) of GDxECC and SD-OCT in the diagnosis of early glaucoma.
Methods: :
twenty-four glaucomatous patients and 32 healthy subjects underwent a complete ophthalmological examination, visual field (VF) testing by standard automated perimetry (Humphrey Field Analyzer Carl Zeiss Meditec) and RNFL assessment by GDxECC (Carl Zeiss Meditec Inc.) and SD-OCT (Heidelberg Engineering Inc.). Early VF defect and normal VF were classified according to Hodapp-Parrish-Anderson classification. All tests were reliable (false positive <15%; fixation losses and false-negative responses <25%) and the last repetition was included in the analysis. GDxECC and SD-OCT were performed randomly within one week. GDxECC single exam, GDxECC triple exam and the average of three measurements by SD-OCT were included in the analysis. The areas under the receiver operating characteristic curve (AUROCs) were calculated . The Kappa statistic was used to quantify and evaluate the agreement between tests.
Results: :
both GDxECC single exam and GDxECC triple exam had excellent DA of all parameters : Temporal-Superior-Nasal-Inferior-Temporal Avarage (TSNIT AV), Nerve Fiber Indicator (NFI), Superior Avarage (SUP AV) and Inferior Avarage (INF AV) (respectively AUCs= 1; 0,99; 0,90; 0,99 and 0,99; 0,98; 0,92; 0,94). The agreement between GDxECC single exam and GDxECC triple exam was very good (Κ=0,85). SD-OCT had excellent DA for Superior, Inferior, Nasal and Global parameters (respectively AUCs= 0,94; 0,99; 0,96; 0,99) but poor DA for Temporal sector (AUC=0,69). GDxECC classification had a sensibility of 80% and a specificity of 100% both for single and triple exam, while SD-OCT classification had a sensibility of 85,71% and a specificity of 100%. The agreement between tests classification was good (Κ=0,64).
Conclusions: :
our study suggests that both GDxECC and SD-OCT are useful instruments in the diagnosis of early glaucoma with high DA and high specificity.
Keywords: imaging/image analysis: clinical • nerve fiber layer