Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) for neovascular age-related macular degeneration: a cross-sectional diagnostic accuracy study

Abstract

Objectives: Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) is a novel OCT technology that was specifically designed for home monitoring of neovascular age-related macular degeneration (AMD). First clinical findings have been reported before. This trial investigates an improved prototype for patients with AMD and focusses on device operability and diagnostic accuracy compared with established spectral-domain OCT (SD-OCT).

Design: Prospective single-arm diagnostic accuracy study.

Setting: Tertiary care centre (University Eye Clinic).

Participants: 46 patients with age-related macular degeneration.

Interventions: Patients received short training in device handling and then performed multiple self-scans with the SELFF-OCT according to a predefined protocol. Additionally, all eyes were examined with standard SD-OCT, performed by medical personnel. All images were graded by at least 2 masked investigators in a reading centre.

Primary outcome measure: Rate of successful self-measurements.

Secondary outcome measures: Sensitivity and specificity of SELFF-OCT versus SD-OCT for different biomarkers and necessity for antivascular endothelial growth factor (anti-VEGF) treatment.

Results: In 86% of all examined eyes, OCT self-acquisition resulted in interpretable retinal OCT volume scans. In these patients, the sensitivity for detection of anti-VEGF treatment necessity was 0.94 (95% CI 0.79 to 0.99) and specificity 0.95 (95% CI 0.82 to 0.99).

Conclusions: SELFF-OCT was used successfully for retinal self-examination in most patients, and it could become a valuable tool for retinal home monitoring in the future. Improvements are in progress to reduce device size and to improve handling, image quality and success rates.

Trial registration number: DRKS00013755, CIV-17-12-022384.

Keywords: medical retina; ophthalmology; vetreoretinal.

Figure 1

The Self-Examination Low-Cost Full-Field Optical Coherence Tomography prototype. Left: the three-dimensional-printed headrest is mounted on horizontal rails and can be slid freely so that both eyes can be measured. Right: author MMo demonstrates the patient’s head position during measurement.

Figure 2

Flow diagram illustrating data selection for final sensitivity and specificity analysis. DME, diabetic macular oedema; VA, visual acuity.

Figure 3

Patient demographics and characteristics of all successfully measured eyes. BCVA, best-corrected visual acuity.

Figure 4

Foveal B-scans of three representative patients acquired with spectral-domain OCT (SD-OCT) (top) and Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) (bottom). Subretinal fluid (SRF) can be found in patient 1 and 2, intraretinal fluid (IRF) in patient 3 and pigment epithelium detachment (PED) in all patients. VA, visual acuity.

Figure 5

Comparison between first (v1) and second (v2) prototype. Note that the measurement of the first prototype was on a different date than spectral-domain OCT (SD-OCT) and second prototype measurement; therefore, not biomarkers, but only overall image quality and signal-to-noise ratio (SNR) can be compared. SELFF-OCT, Self-Examination Low-Cost Full-Field Optical Coherence Tomography; VA, visual acuity.

Figure 6

Comparison of intraretinal fluid (IRF) demarcation two patients with different image quality. In patient 3 (high signal-to-noise ratio (SNR)), IRF was found by all raters in both spectral-domain OCT (SD-OCT) and regular contrast Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) (green ellipses). With ultra-high contrast, the IRF demarcates even better. In patient 6 (low SNR), IRF was virtually unrecognisable and overlooked by all raters in SELFF-OCT (red ellipsis). A band-shaped horizontal motion artefact (yellow arrows) makes the distinguishability even harder. With ultra-high contrast, the IRF becomes more pronounced. Because patient 4 showed no other activity signs in this eye than the IRF shown, this was one of two eyes that was missed in antivascular endothelial growth factor treatment necessity sensitivity analysis. VA, visual acuity.