Scanning the macula for detecting glaucoma.
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Date
2014-01
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Abstract
Background: With the advent of spectral domain optical coherence tomography (SDOCT), there has been a
renewed interest in macular region for detection of glaucoma. However, most macular SDOCT parameters
currently are thickness parameters which evaluate thinning of the macular layers but do not quantify the
extent of area over which the thinning has occurred. We therefore calculated a new macular parameter,
“ganglion cell complex surface abnormality ratio (GCC SAR)” that represented the surface area over which
the macular thickness was decreased. Purpose: To evaluate the ability of SAR in detecting perimetric and
preperimetric glaucoma. Design: Retrospective image analysis. Materials and Methods: 68 eyes with
perimetric glaucoma, 62 eyes with preperimetric glaucoma and 165 control eyes underwent GCC imaging
with SDOCT. SAR was calculated as the ratio of the abnormal to total area on the GCC signifi cance
map. Statistical Analysis: Diagnostic ability of SAR in glaucoma was compared against that of the
standard parameters generated by the SDOCT soft ware using area under receiver operating characteristic
curves (AUC) and sensitivities at fi xed specifi cities. Results: AUC of SAR (0.91) was statistically signifi cantly
bett er than that of GCC average thickness (0.86, P = 0.001) and GCC global loss volume (GLV; 0.88, P = 0.01)
in diff erentiating perimetric glaucoma from control eyes. In diff erentiating preperimetric glaucoma from
control eyes, AUC of SAR (0.72) was comparable to that of GCC average thickness (0.70, P > 0.05) and
GLV (0.72, P > 0.05). Sensitivities at specifi cities of 80% and 95% of SAR were comparable (P > 0.05 for
all comparisons) to that of GCC average thickness and GLV in diagnosing perimetric and preperimetric
glaucoma. Conclusion: GCC SAR had a bett er ability to diagnose perimetric glaucoma compared to the
SDOCT soft ware provided global GCC parameters. However, in diagnosing preperimetric glaucoma, the
ability of SAR was similar to that of soft ware provided global GCC parameters.
Description
Keywords
Ganglion cell complex, spectral domain optical coherence tomography, surface abnormality ratio
Citation
Begum Viquar U, Jonnadula Ganesh B, Yadav Ravi K, Addepalli Uday K, Senthil Sirisha, Choudhari Nikhil S, Garudadri Chandra S, Rao Harsha L. Scanning the macula for detecting glaucoma. Indian Journal of Ophthalmology. 2014 Jan ; 62 (1): 82-87.