Abstract
Purpose :
To determine reference standard optic disc images, stratified by disc size, associated with threshold superior peripheral, superior paracentral, inferior peripheral, and inferior paracentral visual field (VF) loss.
Methods :
Archetype analysis, a computational method to decompose VFs into 17 vision loss patterns/archetypes (AT) with corresponding weighting coefficients to allow for classification of VFs into subtypes, was performed on a data set of 13,231 reliable Humphrey VFs from 2006-2012. VFs with weighting coefficients of >50% for early glaucomatous superior peripheral (AT 3), superior paracentral (AT 14), inferior peripheral (AT 5), and inferior paracentral (AT 16) subtypes were included. Color optic disc photographs within 6 months of VFs were identified and stratified based on Cirrus optical coherence tomography of the retinal nerve fiber layer (OCT-RNFL) measurements of disc area (small <1.5 mm2, medium 1.5-2.0 mm2, large >2.0 mm2). Gradable optic disc images associated with the greatest mean deviation meeting early stage Hodapp-Parrish-Anderson criteria on reproducible VFs were selected. Structural OCT parameters (disc area, rim area, vertical cup-disc ratio (VCDR), average RNFL thickness) were compared based on disc size and VF defect type (peripheral versus paracentral).
Results :
Twelve optic disc images from 12 patients, one for each category of disc size and VF type, were selected as reference standards for threshold VF loss (Figure). Mean OCT-derived structural parameters for all images are shown (Table). Statistically significant differences in disc area (p=0.007) and VCDR (p=0.03) were seen when stratified by optic disc size. Mean deviation on VF was -3.47 ± 1.51 dB for all selected optic discs.
Conclusions :
VCDR associated with threshold VF loss increases with disc size. As in retinopathy of prematurity and diabetic retinopathy in which reference images are used to standardize definitions of disease, the Threshold Optic Disc Standards (TODS) image library derived using these methods may be helpful to predict VF loss associated with optic disc images in telemedicine settings or patients unable to reliably perform VFs. Further refinement using additional datasets and validation of the diagnostic accuracy of the TODS image library in distinguishing glaucoma suspect and glaucomatous optic discs are needed.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.