Toward a Real-world Optical Coherence Tomography Reference Database: Optometric Practices as a Source of Healthy Eyes

Abstract

Significance: The reports from optical coherence tomography (OCT) instruments depend on a reference database (RDB) of healthy eyes. Although these RDBs tend to be relatively small, they are time consuming and expensive to obtain. A larger RDB should improve our ability to screen for diseases such as glaucoma.

Purpose: To explore the feasibility of developing a large RDB from OCT scans obtained by optometrists as part of their pre-test gathering of information, we tested the hypothesis that these scans are of sufficient quality for an RDB and contain a relatively low base rate of glaucoma and other pathologies (OPs).

Methods: Optical coherence tomography widefield (12 × 9 mm) scans from 400 eyes of 400 patients were randomly selected from a data set of more than 49,000 scans obtained from four optometry sites. Based on a commercial OCT report and a previously validated reading center method, two OCT graders categorized eyes as unacceptable to use for RDB, healthy (H), optic neuropathy consistent with glaucoma (ON-G), glaucoma suspect, or OPs.

Results: Overall, 29 (7.25%) of the eyes were graded unacceptable. Of the remaining 371 eyes, 352 (94.9%) were graded H. Although, for one site, 7.4% of the eligible eyes were graded ON-G, the average for the other three sites was 1.4%. Adjustments of the reading center criteria resulted in exclusion of more than half of these ON-G and OP eyes.

Conclusions: The OCT scans obtained from optometry practices as part of their pre-test regimen are of sufficient quality for an RDB and contain a relatively low base rate of glaucoma and OPs. With the suggested exclusion criteria, the scans from optometry practices that are primarily involved in refraction and medical screening services should yield a large, real-world RDB with improved specificity and a base rate of glaucoma and/or OPs comparable with existing RDB.

Figure 1.

The commercial Hood Report containing retinal nerve fiber layer (RNFL) (upper right solid red rectangle) and ganglion cell plus inner plexiform layer (GCL+) (lower right red rectangle) probability (P−) maps. These p-maps are based upon the RNFL and GCL+ thickness maps by comparing the local values of an individual’s thickness maps to that of normative age-corrected values. Every scan was rotated to a common fovea-to-disc angle, which partially accounts for head-eye torsion and some anatomical differences.

Figure 2.

(A) The derived circumpapillary b-scan images for 3 of the scans judged “Unacceptable” for use in a real-world (RW) reference database (RDB). (B) Same for 3 scans judged “Acceptable” for use in a RDB. (C) The GCL+ thickness maps for 3 of the scans judged “Unacceptable” for use in a RW-RDB. (D) Same for 3 scans judged “Acceptable” for use in a RDB.

Figure 3.

The Image Quality from the commercial software for all 400 scans. The green symbols are the scans judged to be “Unacceptable” and the open symbols the scans judged to be “Acceptable”. Symbols are displaced along the y-axis for clarity.

Figure 4.

The Hood Report for 4 of the 11 eyes judged to be optic neuropathy consistent with glaucoma (ON-G). A, B. from site 2. C, D. from the other sites.