Replication and Refinement of an Algorithm for Automated Drusen Segmentation on Optical Coherence Tomography

Here, we investigate the extent to which re-implementing a previously published algorithm for OCT-based drusen quantification permits replicating the reported accuracy on an independent dataset. We refined that algorithm so that its accuracy is increased. Following a systematic literature search, an algorithm was selected based on its reported excellent results. Several steps were added to improve its accuracy. The replicated and refined algorithms were evaluated on an independent dataset with the same metrics as in the original publication. Accuracy of the refined algorithm (overlap ratio 36–52%) was significantly greater than the replicated one (overlap ratio 25–39%). In particular, separation of the retinal pigment epithelium and the ellipsoid zone could be improved by the refinement. However, accuracy was still lower than reported previously on different data (overlap ratio 67–76%). This is the first replication study of an algorithm for OCT image analysis. Its results indicate that current standards for algorithm validation do not provide a reliable estimate of algorithm performance on images that differ with respect to patient selection and image quality. In order to contribute to an improved reproducibility in this field, we publish both our replication and the refinement, as well as an exemplary dataset

Comparability of automated drusen volume measurements in age-related macular degeneration: a MACUSTAR study report

Drusen are hallmarks of early and intermediate age-related macular degeneration (AMD) but their quantification remains a challenge. We compared automated drusen volume measurements between different OCT devices. We included 380 eyes from 200 individuals with bilateral intermediate (iAMD, n = 126), early (eAMD, n = 25) or no AMD (n = 49) from the MACUSTAR study. We assessed OCT scans from Cirrus (200 × 200 macular cube, 6 × 6 mm; Zeiss Meditec, CA) and Spectralis (20° × 20°, 25 B-scans; 30° × 25°, 241 B-scans; Heidelberg Engineering, Germany) devices. Sensitivity and specificity for drusen detection and differences between modalities were assessed with intra-class correlation coefficients (ICCs) and mean difference in a 5 mm diameter fovea-centered circle. Specificity was > 90% in the three modalities. In eAMD, we observed highest sensitivity in the denser Spectralis scan (68.1). The two different Spectralis modalities showed a significantly higher agreement in quantifying drusen volume in iAMD (ICC 0.993 [0.991–0.994]) than the dense Spectralis with Cirrus scan (ICC 0.807 [0.757–0.847]). Formulae for drusen volume conversion in iAMD between the two devices are provided. Automated drusen volume measures are not interchangeable between devices and softwares and need to be interpreted with the used imaging devices and software in mind. Accounting for systematic difference between methods increases comparability and conversion formulae are provided. Less dense scans did not affect drusen volume measurements in iAMD but decreased sensitivity for medium drusen in eAMD

Secondary and Exploratory Outcomes of the Subthreshold Nanosecond Laser Intervention Randomized Trial in Age-Related Macular Degeneration: A LEAD Study Report

Purpose:To evaluate the secondary and exploratory outcomesof the Laser Intervention in Early Stages of Age-Related MacularDegeneration (LEAD) study, a 36-month trial of a subthresholdnanosecond laser (SNL) treatment for slowing the progression tolate age-related macular degeneration (AMD) in its early stages.Design:Multicenter, randomized, sham-controlled trial.Participants:Two-hundred ninety-two patients with bilaterallarge drusen.Methods:Participants were randomly assigned to receive SNLor sham treatment to the study eye at 6-month intervals.Main Outcome Measures:The secondary outcome measure ofthe LEAD study was the time to development of late AMD, definedby multimodal imaging in the nonestudy eye. The exploratoryoutcome measures were the rate of change in best-corrected visualacuity (BCVA), low-luminance visual acuity, microperimetric meansensitivity, drusen volume in the study and nonestudy eyes, andparticipant-reported outcomes based on the Night Vision Question-naire and Impact of Vision Impairment questionnaire.Results:Progression to late AMD in the nonestudy eye wasnot significantly delayed with SNL treatment (hazard ratio, 0.83;95% confidence interval, 0.40e1.71;P¼0.611). There was noevidence of effect modification based on the coexistence of retic-ular pseudodrusen; interactionP¼0.065). There was no signifi-cant difference between study groups in the rate of change of low-luminance visual acuity, microperimetric mean sensitivity, anddrusen volume in the study or nonestudy eyes, and Night VisionQuestionnaire and Impact of Vision Impairment questionnaire2 scores (allP 0.167). The rate of BCVA decline was slightlyhigher for participants in the SNL group compared with the shamtreatment group in the study eye (e0.54 and 0.23 letters/year,respectively;P<0.001) but not the nonestudy eye (e0.48 ande0.56 letters/year, respectively;P¼0.628).Conclusions:Subthreshold nanosecond laser treatment of oneeye did not have an effect on delaying progression to late AMD in thefellow eye and did not, in general, have an impact on the exploratorystructural, functional, and participant-reported outcomes.Zhichao Wu, Chi D. Luu, Lauren A.B. Hodgson, Emily Caruso, Kate H. Brassington, Nicole Tindill, Khin Zaw Aung, Colin A. Harper, Sanjeewa S. Wickremasinghe, Sukhpal S. Sandhu, Myra B. McGuinness, Fred K. Chen, Usha Chakravarthy, Jennifer J. Arnold, Wilson J. Heriot, Shane R. Durkin, Maximilian W.M. Wintergerst, Shekoufeh Gorgi Zadeh, Thomas Schultz, Robert P.Finger, Amy C. Cohn, Elizabeth K.Baglin, Pyrawy Sharangan, Robyn H. Guymer, for the LEAD Study Grou