Evaluation of a Qualitative Approach for Detecting Glaucomatous Progression Using Wide-Field Optical Coherence Tomography Scans

Abstract

PurposeTo determine the effectiveness of detecting glaucomatous progression by a qualitative evaluation of wide-field (12 × 9 mm) scans on optical coherence tomography imaging. This method was compared to a conventional quantitative analysis of the global circumpapillary retinal nerve fiber layer (cpRNFL) thickness.MethodsA total of 409 eyes with a clinical diagnosis of glaucoma or suspected glaucoma for which two wide-field scans were obtained at least 1 year apart (n = 125) and within one session (n = 284) were included to determine the sensitivity of detecting progression at 95% specificity. Qualitative OCT evaluation was performed in a similar manner to flicker chronoscopy by superimposing the two scans, and the progression probability was graded. A quantitative event-based analysis of the global cpRNFL thickness also was performed.ResultsThirty-three and 25 eyes were deemed to have progressed based on qualitative and quantitative approaches, respectively (P = 0.152). A post hoc review of cases where the two methods disagreed revealed that all eyes missed by the quantitative analysis had established glaucomatous damage that appeared to show characteristic patterns of progression. All eyes missed by the qualitative evaluation appeared to be free of such established damage, and instead showed a generalized reduction in cpRNFL thickness.ConclusionsQualitative evaluation of OCT imaging information more frequently detected change consistent with known patterns of glaucomatous progression than global cpRNFL thickness, warranting further studies to evaluate its value.Translational RelevanceA framework for qualitatively evaluating progressive glaucomatous changes on OCT imaging clinically shows promise.

Structure-Function Agreement Is Better Than Commonly Thought in Eyes With Early Glaucoma

“…OCT wide-field reports were generated by using a reference database from the OCT device manufacturers (data provided by Topcon, Inc.), as previously described 10. This original report was modified so that all eyes were aligned on the same fovea-to-disc angle 11. This corrects for head-eye torsion, as well as perhaps some anatomical differences.…”

“…The report based upon a wide-field swept-source OCT volume scan (see text and Hood et al10 and Wu et al11). The RFNL (upper right, red rectangle) and RGC+ (lower right, red rectangle) probability maps are shown in field view (i.e., the top of each corresponds to the upper visual field/inferior retina).…”

An Automated Method for Assessing Topographical Structure–Function Agreement in Abnormal Glaucomatous Regions

“…In order to correct for head-eye torsion, as well as some FD angle-related anatomical differences (see Fig. 16 in Hood et al 7 ), we rotated each scan such that the individual's FD vector aligned with the mean FD vector calculated from the reference database 8 ; we call these “rotated scans.” RNFL and RGC+ thickness probability values, along with their corresponding coordinates, were extracted from both unrotated and “rotated” scans. Since the “rotated” scans showed slightly, but not significantly, better performance in assessing aS-aF agreement (see Supplementary Table S1 for more information), we used the results of “rotated” scans.…”

“…In order to correct for head-eye torsion, as well as some FD angle-related anatomical differences (see Fig. 16 in Hood et al 7 ), we rotated each scan such that the individual's FD vector aligned with the mean FD vector calculated from the reference database 8 ; we call these "rotated scans." RNFL and RGC+ thickness probability values, along with their corresponding coordinates, were extracted from both unrotated and "rotated" scans.…”

21st century glaucoma care

“…Different targets that specify damage better are needed. Some argue for more testing in the central visual field [31]. And, shorter test times would be welcomed by all.…”