CNV DETECTION

A home monitoring device could prove a useful ally in detecting the development of choroidal neovascularisation (CNV) at an earlier stage than current standard of care approaches, and ultimately lead to better preservation of visual acuity at the time of CNV detection, according to Usha Chakravarthy MD.

“The latest results confirmed a previous smaller study that we carried out, which showed that the home monitoring device could detect conversion to wet AMD at a stage when visual acuity was unaffected,” Dr Chakravarthy told delegates attending the 14th EURETINA Congress in London.

Dr Chakravarthy, professor of ophthalmology and vision sciences, Queen’s University Belfast, Northern Ireland, said that even in the current era of anti-VEGF treatments it is still important to consider the fact that early treatment results in better maintenance of visual acuity.

“It is very obvious looking at recent data that, even when patients are included in various AMD studies, they still present late with CNV, with high proportions of them having lower visual acuity outcomes as a result,” she said.

Presenting the results of the Age-Related Eye Disease Study 2 (AREDS2) – Home Monitoring of the Eye (HOME) study, Dr Chakravarthy said that the researchers wanted to determine whether home monitoring with the ForeseeHome device (Notal Vision Ltd) resulted in earlier detection of AMD-related CNV, reflected in better visual acuity, when compared with standard care.

The ForeseeHome device uses macular visual field testing with preferential hyperacuity perimetry techniques and telemonitoring to detect early signs of CNV, said Dr Chakravarthy. Each scan takes about three minutes per eye, with the resulting data used to establish a baseline for the patient.

Data analysis compares the patient’s readings to a normative database and leads to the identification of new visual field defects. If the device detects significant change over time, an alert is triggered which is then transmitted to the clinician.

The study population included AREDS2 and non-AREDS2 patients with at least one large drusen greater than 125 microns in one or both eyes and a visual acuity of at least 20/60 and absence of advanced AMD.

A total of 1,970 participants, between 53 and 90 years of age and at high risk of developing CNV, were screened at 44 different centres, with 1,520 meeting the inclusion criteria. Patients were randomised into two groups - 763 participants in the ForeseeHome device monitoring arm and 757 participants who followed standard care procedures in the control group.

SCORES

The main outcome measure was the difference in best corrected visual acuity scores between baseline and detection of CNV. The event was determined by investigators based on clinical examination, colour fundus photography, fluorescein angiography and optical coherence tomography findings.

The results showed that 51 patients progressed to CNV in the device arm and 31 in the control arm at the time of analysis. For the standard care group, the mean visual acuity at the time of detection was a -9 letter change from baseline, compared to -4 letters for the device arm.

The proportion of eyes maintaining visual acuity of 20/40 or better at the time of CNV detection was 62 per cent for standard care and up to 94 per cent for those patients who followed the device usage protocol as instructed. There was also a decreased likelihood of between 50 and 76 per cent of losing three lines of vision for patients in the device monitoring group.

The study results also showed that the first modality to alert to CNV development was the device arm.

“The data showed that, if the device is used as instructed, the likelihood that it will be the first to alert to CNV increases,” said Dr Chakravarthy.

Usha Chakravarthy:
u.chakravarthy@qub.ac.uk