A method for determining the volume of a region of interest of a biological tissue using optical coherence tomography, the method comprising: a) acquiring three-dimensional optical coherence tomography data comprising at least a first retinal segment and a second retinal segment comprising the region of interest, wherein the segments represent tissue layers; b) acquiring two-dimensional image data comprising the region of interest; c) drawing the boundary around the region of interest in the two-dimensional image data, the boundary enclosing an area A, wherein a user draws the boundary around the region of interest or wherein a user draws a plurality of points indicating the boundary around the region of interest, wherein the two-dimensional image data and three dimensional optical coherence tomography data are registered so that the boundary drawn on the two-dimensional image and displayed on a computer screen provides an associated, coordinated boundary around the region of interest in the three-dimensional optical coherence tomography data; d) calculating a volume v defined in the three-dimensional optical coherence tomography data by the first segment and the second segment and by extension of the boundary through the segments; e) calculating the average thickness t between the first segment and the second segment along the boundary; and f) calculating the volume of the region of interest V = v - (t × A), wherein: - the region of interest is a lesion in the biological tissue, or - the biological tissue is retinal tissue and the region of interest is a retinal lesion, or - the biological tissue is retinal tissue and the region of interest is a central neovascularization lesion complex. a) acquiring three-dimensional optical coherence tomography data comprising at least a first retinal segment and a second retinal segment comprising the region of interest, wherein the segments represent tissue layers; b) acquiring two-dimensional image data comprising the region of interest; c) drawing the boundary around the region of interest in the two-dimensional image data, the boundary enclosing an area A, wherein a user draws the boundary around the region of interest or wherein a user draws a plurality of points indicating the boundary around the region of interest, wherein the two-dimensional image data and three dimensional optical coherence tomography data are registered so that the boundary drawn on the two-dimensional image and displayed on a computer screen provides an associated, coordinated boundary around the region of interest in the three-dimensional optical coherence tomography data; d) calculating a volume v defined in the three-dimensional optical coherence tomography data by the first segment and the second segment and by extension of the boundary through the segments; e) calculating the average thickness t between the first segment and the second segment along the boundary; and f) calculating the volume of the region of interest V = v - (t × A), wherein: - the region of interest is a lesion in the biological tissue, or - the biological tissue is retinal tissue and the region of interest is a retinal lesion, or - the biological tissue is retinal tissue and the region of interest is a central neovascularization lesion complex. - the region of interest is a lesion in the biological tissue, or - the biological tissue is retinal tissue and the region of interest is a retinal lesion, or - the biological tissue is retinal tissue and the region of interest is a central neovascularization lesion complex.