[Volumetric analysis of vascularized pigment epithelium detachment in AMD: post hoc analysis of the RECOVER study]

The ratio of choroidal neovascularization (CNV) and pigment epithelium detachment (PED) represents an important parameter regarding the risk of developing a tear of the retinal pigment epithelium (RPE) in patients with vascularized PED due to age-related macular degeneration (AMD).

Within the framework of the RECOVER study a total of 29 treatment-naive patients with vascularized PED underwent fluorescein angiography (FA), indocyanine green angiography (ICGA) and optical coherence tomography (OCT) volume scans. The CNV-PED ratio was evaluated retrospectively by two independent graders in three ways: 1) manually based on the en face image of the FA late phase and 2) manually based on the en face image of the ICGA late phase. 3) In every OCT scan encompassing the PED, the area between the RPE and Bruch's membrane and the CNV area was measured and multiplied by the distance between OCT scans in order to determine volumetric data of CNV, PED and the serous cavity.

The FA and ICGA showed a mean serous area of 6.14 ± 4.21 mm² (ICGA 5.94 ± 4.13 mm²), a mean CNV area of 3.25 ± 1.79 mm² (ICGA 2.84 ± 1.68 mm²) and a mean PED area of 9.39 ± 4.27 mm² (ICGA 8.79 ± 4.23 mm²) resulting in a mean two-dimensional morphological ratio of 0.35 ± 0.21 (ICGA 0.32 ± 0.22). The volumetric measurement revealed a mean CNV volume of 0.63 ± 0.67 mm³, a mean serous volume of 3.61 ± 3.83 mm³ and a mean total PED volume of 4.25 ± 3.68 mm³. The mean three-dimensional morphological ratio was 0.15 ± 0.29. The difference between the two-dimensional ratios of FA (p < 0.0001) and ICGA (p = 0.0004) was significant compared to the three-dimensional OCT ratio.

Assessment of the CNV-PED ratio using volumetric OCT measurements is an additional tool to the en face modalities FA and ICGA. This seems to be clinically relevant regarding the risk stratification of RPE tear development in PED patients and for the planning of the treatment regimen.