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Saeideh Ghahghaei, Laura Walker; SKERI-VF: a graphical user interface to map scotoma and PRL with the Optos OCT/SLO. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5182.
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© ARVO (1962-2015); The Authors (2016-present)
Clinicians/scientists usually use subjective measures to report monocular scotoma area/diameter and fixation characteristics from the scanner laser ophthalmoscope (SLO) perimetry images in macular degeneration (MD). There is no great way to measure binocular field loss while controlling for eye movements. We developed a tool to quantify PRL and scotoma total area and locations relative to the native fovea.
Walker-Renninger et al (Renninger, Psomadakis, Dang & Fletcher, 2008) suggested a novel method to objectively estimate the monocular scotoma area from perimetry in MD based on (i) an optic-disc based estimation of the location of the fovea and (ii) the increase in the receptive field size with eccentricity. Here, we introduce a new tool (GUI) that applies this method to data from the Optos OCT/SLO. With OCT, it is sometimes possible to locate the foveal pit in MD. The GUI takes the perimetry, fixation stability and OCT image of each eye as input. It outputs the scotoma area and map relative to the PRL and the estimated fovea. The GUI computes BCEA of the PRL and reports the fovea-PRL distance. A prediction of the binocular scotoma map/area is computed, assuming that the foveae in the two eyes are aligned.
Figure 1 shows (A) perimetry , (B) fixation stability SLO images and (C) the location of the fovea pit in an OCT image for a patient with MD. Figure 2 shows the output of the GUI for OS (2A), OD (2B) and OU (2C). These results can be saved. This helps researchers/clinicians to keep track of any changes over time. Different labs in our institute have been using the GUI. For example, given that patients are usually unaware of their scotoma, the illustration of the predicted binocular scotoma can be helpful. PRL-fovea distance is valuable information for PRL training. PRLs in roughly corresponding locations suggest the possibility of depth perception. The GUI is a free Windows application available on our website (http://www.ski.org/project/skeri-vf). A user manual is provided.
Quantifying scotoma area and PRL location is important for tracking disease progression, assessing the impact of intervention and for guiding eccentric viewing training in low vision rehabilitation. This GUI provides a valuable tool for computing these metrics, with the added potential of predicting quantitative binocular fields.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Figure 1. Input images.
Figure 2. Outputs of the GUI.
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