Abstract
Purpose:
To compare structural optic nerve and peripapillary features observed using nonmydriatic, stereoscopic, 200° Optomap ultrawide field imaging (UWFI) and mydriatic, stereoscopic 30° ETDRS standard field 1, 35mm color slide photographs (ETDRS Photos).
Methods:
Both eyes of 25 diabetic (DM) subjects underwent UWFI and ETDRS photos at the same visit. Two independent, masked glaucoma specialists (BJS & LRP) graded structural optic nerve head and peripapillary features indicative of glaucoma. Imaging modalities were evaluated separately and disparities adjudicated by consensus. Modality agreement and inter-grader agreement were determined by weighted kappa (κ) statistic for vertical and horizontal cup/disc ratio (CDR), and unweighted κ for nominal data such as disc tilt (graded as None, Horizontal, or Vertical). Agreement definition for κ was poor (< 0.20), fair (0.21-0.40), moderate (0.41-0.60), or good (0.61-0.80). Optic nerve rim characteristics were graded as normal or thinned (concentric, superior, inferior, or superior & inferior).
Results:
Mean age was 56.5±11.9 years; 50% male, 60% type 1 DM and mean DM duration 21.7±13.8 (4-49) years. Based on ETDRS photos (N=50 eyes), diabetic retinopathy (DR) was absent in 34%, mild nonproliferative DR (NPDR) in 24%, moderate NPDR in 34%, and severe/very severe NPDR in 8%. Agreement between modalities was good for optic nerve rim characteristics (κ= 0.71±0.16), rim abnormalities (0.70±0.16), suspicion for glaucoma (0.73±0.13) and need to refer for glaucoma evaluation (0.79±0.12). Agreement was moderate for disc size (0.58±0.13), vertical CDR (0.46±0.07), horizontal CDR (0.51±0.09) and peripapillary atrophy (0.46±0.19). Agreement was fair for presence of retinal nerve fiber layer (RNFL) defect (0.22±0.18). The green channel on UWFI detected more RNFL defects (14.3%) than ETDRS photos (2%) but this difference was not statistically significant (P=0.17). Agreement was poor for cup depth, disc tilt and disc pallor.
Conclusions:
In this cohort of DM patients with varying levels of DR severity, there was good agreement between UWFI and ETDRS photos for critical rim abnormalities and for suspicion of glaucoma requiring referral for further evaluation. Given the benefits of UWFI in teleophthalmology programs for DR, UWFI may also be potentially useful in evaluation of glaucoma in such settings.
Keywords: 629 optic nerve •
627 optic disc •
550 imaging/image analysis: clinical