Performance of a Smart Device over 12-Months for Home Monitoring of Patients with Intermediate Age-Related Macular Degeneration

Abstract

Background: To determine the 12-month compliance with and retention of home monitoring (HM) with Melbourne Rapid Fields (MRFh) for patients with intermediate age-related macular degeneration (iAMD) and compare visual acuity (VA) and retinal sensitivity (RS) results to clinical measures.

Methods: Participants were recruited to a 12-month HM study with weekly testing of vision with MRFh. Inclusion criteria were a diagnosis of iAMD, understand English instructions, VA ≥ 20/40, and access to an iPad. Supervised in-clinic testing of high contrast VA (HVA, ETDRS), low-luminance VA (LLVA, ETDRS with ND2 filter), and RS (Macular Integrity Assessment, MAIA, and MRF in-clinic, MRFc) was conducted every 6-months.

Results: A total of 54 participants (67 ± 6.8 years) were enrolled. Compliance to weekly HM was 61% and study retention at 12-months was 50% of those with uptake (n = 46). No difference was observed between MRFc and MRFh across all RS and VA outcomes (p > 0.05). MRFh RS was higher than MAIA (29.1 vs. 27.1 dB, p < 0.001). MRFh HVA was not different from ETDRS (p = 0.08), but LLVA was 9 letters better (81.5 vs. 72.4 letters, p < 0.001).

Conclusions: Over 12-months, MRFh yields a moderate level of compliance with (61%) and retention (50%) of weekly testing. Further studies are required to assess the ability of MRFh to detect early progression to nAMD.

Keywords: age-related macular degeneration; home-monitoring; iPad; microperimetry; tablet device; telemedicine; visual fields.

Figure 1

The Melbourne Rapid Fields vision testing application. (a) The visual acuity Landolt C targets. (i) High contrast visual acuity (HVA, L_b: 135 cd/m², contrast: 94%). (ii) Low-luminance visual acuity (LLVA, L_b: 5 cd/m², contrast: 86%). (b) Patients adopt a 4-alternate-forced-choice to identify the orientation of the target shown in the central box. (c) Visual field protocol. Unfilled circles represent MAIA test spot locations and filled circles denote the MRF grid. Note size scaling of MRF stimuli occurs away from fixation. Black ring is 10° eccentricity. (d) The visual field task. App-generated audio prompts instruct participants to look at the red fixation cross and tap in the designated ‘touch zone’ when a stimulus is observed.

Figure 2

Timeline for the 12-month voice-guided telemedicine study outlined in the text. VA: Early Treatment Diabetic Retinopathy Study acuity chart viewed under normal clinical conditions (HVA) and through an ND2 filter (LLVA). OCT: Optical coherence tomography. Fundus: Dilated fundus exam. MAIA: Macular Integrity Assessment. MRFc: Melbourne Rapid Fields visual acuity and visual field testing performed in-clinic under supervision (cartoon of person at these times). MRFh: Melbourne Rapid fields visual acuity and visual fields performed at-home with app-generated audio prompts (cartoon of speaker at these times). Survey: Survey of participant perceptions of self-monitoring after 12-months.

Figure 3

CONSORT diagram for the long-term Melbourne Rapid Fields home (MRFh) study. n = 54. Shaded box indicates the number of participants with uptake.

Figure 4

Survival and compliance of n = 46 iAMD participants to the request for MRFh over a 52-week period. (a). Survival of participants over 52 weeks of MRFh. (b). Compliance rate to weekly testing (7 + 1 days, solid line). Dotted line represents average compliance rate over the 52-week period.

Figure 5

Mean absolute error (MAE, dB) from the median retinal sensitivity calculated from the average of 3 MAIA tests performed in-clinic (circles) and 26 MRFh tests performed at home (triangles) in n = 46 participants with intermediate AMD. The unfilled triangles are shown from week 2 and represent a period of learning where the MAE approaches its plateau. Error bars show SEM. The black dotted line shows the MAE of the MAIA at week 26. Grey zone represents 2x SEM of the 6-month MAIA result.

Figure 6

Survey responses on the ease of use of the MRF iPad application from n = 40 participants with iAMD. * Indicates mean is significantly removed from the neutral state of 2.5, p < 0.01. MAIA = Macular Integrity Assessment.