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The following is a summary of “Repeatability of Microperimetry in areas of RPE and Photoreceptor loss in Geographic Atrophy supported by AI-based OCT biomarker quantification,” published in the November 2024 issue of Ophthalmology by Coulibaly et al. 

There is growing interest in using microperimetry (MP) or fundus-controlled perimetry (FCP) as a targeted psychometric testing method for geographic atrophy (GA) due to the disease’s subclinical or extra-foveal appearance and unreliable visual acuity from preexisting foveal loss.  

Researchers conducted a retrospective study to establish comprehensive pointwise test-retest repeatability reference values for widely used MP devices and to guide the interpretation of sensitivity loss in patients with GA by combining the values with targeted retinal pigment epithelium (RPE) and photoreceptor (PR) integrity testing.  

They assessed patients with GA by using CenterVue (iCare) MAIA and NIDEK MP3 devices; PWS measurements were co-registered with optical coherence tomography (OCT) volume scans. Areas with RPE and PR loss, drusen, PR thickness, and hyperreflective foci (HRF) volume were identified and quantified using deep learning algorithms. Test-retest repeatability was evaluated using Bland-Altmann coefficients of repeatability (CoR) for biomarker-specific areas. An Inter-device correlation, scotoma point detection repeatability, and potential fixation stability effects were also assessed.  

The results showed that 900 stimuli per device from 20 subjects were included. Both MAIA (±6.57) and MP3 (±6.59) had similar overall PWS test-retest variance, integrity loss was associated with higher test-retest variance on both devices (MAIA: P =0.002; MP3: P <0.001). Higher CoR for RPE loss (±10.99 vs ±5.34) and HRF (±9.21 vs ±6.25) areas was observed only on MP3 (P <0.001 and P =0.01, respectively). Excellent intra-device correlation (MAIA: 0.94[0.93-0.95]; MP3: 0.94[0.94-0.95]) and good inter-device correlation (0.84[0.53-0.92]) were demonstrated. Device, run order, and foveal sparing had no significant impact on fixation stability.  

Investigators concluded that areas with PR integrity loss, especially without RPE loss, revealed higher test-retest variance on MAIA and MP3 devices. 

Source: ajo.com/article/S0002-9394(24)00520-8/fulltext