Targeted Microperimetry Grids for Focal Lesions in Intermediate AMD: PINNACLE Study Report 7

Abstract

Purpose: The purpose of this study was to evaluate the feasibility and utility of optical coherence tomography (OCT)-based, targeted microperimetry grids in assessing focal lesions in intermediate age-related macular degeneration (iAMD).

Methods: The multicenter, prospective PINNACLE study enrolled 395 patients with iAMD aged 55 to 90 years across 12 international sites. Participants underwent imaging, including OCT and microperimetry, every 4 to 12 months over 3 years. Deep learning algorithms detected focal lesions and changes in OCT images, including drusen regression, EZ/IZ loss with hypertransmission, and subretinal fluid, guiding 5-point microperimetry targeted to lesion locations. Data were analyzed using linear mixed models to estimate differences between retinal sensitivity measured by the 5-point focal grids and sensitivity interpolated from the 24-point standard grids.

Results: The final analysis included 93 eyes from 83 patients, assessing 605 of the 5-point targeted grids and standard grids across 235 focal lesions. The Pearson correlation between focally measured sensitivity and interpolated sensitivity was 0.76. However, interpolation from the standard grid could be erroneous, especially in central regions of lesions characterized by EZ/IZ loss with hypertransmission and subretinal fluid. Interpolation errors increased with distance to the nearest measurement point (slope = 2.20 dB per degree, 95% confidence interval [CI] = 1.52 to 2.87). A significant negative relationship was found between interpolation errors and retinal sensitivity, with the highest errors in areas of low sensitivity. Lesion size significantly impacted interpolation errors for EZ/IZ loss with hypertransmission (slope = -19.41 dB/mm², 95% CI = -29.63 to -9.18).

Conclusions: Targeted grids improved the detection and understanding of how focal retinal changes affect visual function in patients with iAMD, supporting the development of therapeutic interventions.

Figure 1.

Methods. (A) An OCT scan highlighting an automatically detected focal lesion. (B) An infrared image generated during the OCT measurement, with the location of the focal lesion marked. (C) The infrared image taken during the 24-point microperimetry measurement overlaid with the 24-point microperimetry grid. (D) The infrared image taken during the 5-point microperimetry measurement, showing the 5-point focal grid positioned at the location of the focal lesion. (E) Background colors represent the predicted retinal sensitivity. Points with black outlines indicate retinal sensitivity measurements from the 24-point standard grid, whereas points with red outlines indicate measurements from the 5-point focal grid.

Figure 2.

Results. (A) Interpolation error estimates categorized by the type of focal lesion and their locations within the 5-point focal microperimetry grid. “Central” refers to the central point in the 5-point grid (see Fig. 1D), whereas “peripheral” refers to the 4 peripheral points in the 5-point grid. (B) Interpolation error estimates based on the distance from the predicted point to the nearest point in the 24-point standard microperimetry grid. (C) Estimated slopes of interpolation error in relation to measured retinal sensitivity. (D) Estimated slopes of interpolation error in relation to the area of the lesion.