Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

Abstract

Citation: Gräfe MGO, van de Kreeke JA, Willemse J, Braaf B, de Jong Y, Tan HS, Verbraak FD, de Boer JF. Subretinal fibrosis detection using polarization sensitive optical coherence tomography. Trans Vis Sci Tech. 2020;9(4):13, https://doi.org/10. 1167/tvst.9.4.13 Purpose: Subretinal fibrosis (SRFib) is an important cause of permanent loss-of-vision diseases with submacular neovascularization, but a reliable diagnostic method is currently missing. This study uses polarization-sensitive optical coherence tomography (PS-OCT) to detect SRFib within retinal lesions by measurement of its birefringent collagen fibers.Methods: Twenty-five patients were enrolled with retinal pathology in one or both eyes containing (1) suspected SRFib, (2) lesions suspected not to be fibrotic, or (3) lesions with doubtful presence of SRFib. All eyes were evaluated for SRFIb using conventional diagnostics by three retinal specialists. PS-OCT images were visually evaluated for SRFib based on cumulative phase retardation, local birefringence, and optic axis uniformity.Results: Twenty-nine eyes from 22 patients were scanned successfully. In 13 eyes, SRFib was diagnosed by all retinal specialists; of these, 12 were confirmed by PS-OCT and one was inconclusive. In nine eyes, the retinal specialists expected no SRFib, which was confirmed by PS-OCT in all cases. In seven eyes, the retinal specialists' evaluations were inconsistent with regard to the presence of SRFib. PS-OCT confirmed the presence of SRFib in four of these eyes and the absence of SRFib in two eyes and was inconclusive in one eye. Conclusions:In 21 out of 22 eyes, PS-OCT confirmed the evaluation of retinal specialists regarding the presence of SRFib. PS-OCT provided additional information to distinguish SRFib from other tissues within subretinal neovascular lesions in 6 out of 7 eyes.Translational Relevance: PS-OCT can identify and quantify SRFib in doubtful cases for which a reliable diagnosis is currently lacking.

Identification and quantification of fibrotic areas in the human retina using polarization-sensitive OCT

“…Currently fibrosis is diagnosed by expert readers by evaluating color fundus photography, fluorescein angiography, and standard OCT, which is subjective and often inconclusive, because fibrotic patterns can be irregular and visual clues given by the aforementioned imaging techniques may be ambiguous. Taking advantage of the birefringent properties of fibrotic tissues, PS-OCT can provide additional contrast and allow for more precise and reliable evaluations [ 34 , 35 , 37 ]. However, previous methods had problems with smaller fibrotic lesions that generate low cumulative retardation, being disturbed by influences of overlying birefringent tissue like the RNFL or HFL [ 34 , 35 ], or required time-consuming visual inspection of B-scans of different contrast modalities [ 37 ].…”

“…Taking advantage of the birefringent properties of fibrotic tissues, PS-OCT can provide additional contrast and allow for more precise and reliable evaluations [ 34 , 35 , 37 ]. However, previous methods had problems with smaller fibrotic lesions that generate low cumulative retardation, being disturbed by influences of overlying birefringent tissue like the RNFL or HFL [ 34 , 35 ], or required time-consuming visual inspection of B-scans of different contrast modalities [ 37 ]. In this work, we developed a new automatic detection algorithm which greatly reduces the work load of expert readers and may provide a faster diagnosis.…”

“…The majority of such algorithms require the use of at least two different polarization states in the sample and/or the reference arm (see, e.g. [ 27 , 37 , 43 , 48 , 57 , 58 ]), which would make the instrument more complicated. One of these methods has already been demonstrated for identifying fibrotic tissue in the retina [ 37 ], however, an automated way to quantify lesion size based on this technique has not yet been reported.…”

“…[ 27 , 37 , 43 , 48 , 57 , 58 ]), which would make the instrument more complicated. One of these methods has already been demonstrated for identifying fibrotic tissue in the retina [ 37 ], however, an automated way to quantify lesion size based on this technique has not yet been reported.…”

“…Fibrotic tissue shows a well-defined axis orientation, identifiable by tissue patches where the axis locally points into the same direction, while surrounding non-birefringent tissue (polarization maintaining or depolarizing) has no well-defined axis orientation, leading to a random pattern of axis orientation that changes from pixel to pixel. This effect was recently used to identify birefringent tissue in the retina [ 36 ] and to detect subretinal fibrosis [ 37 ]. In these works, a new parameter, optic axis uniformity (OAxU) was introduced.…”