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Russell L Woods, Francisco Costela, Michael A Sandberg, Carol Weigel-DiFranco, Tobias Elze; Binocular Visual Field Patterns in Retinitis Pigmentosa. Invest. Ophthalmol. Vis. Sci. 2019;60(9):1821. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Retinitis pigmentosa (RP) is a well-documented retinal degeneration with characteristics patterns of visual field (VF) loss. However, there have been few systematic evaluations of the patterns of VF loss of people with RP, and none examining binocular VFs. We applied unsupervised machine learning to a large sample to calculate representative patterns of RP-related binocular VF loss.
VFs were measured using the 30-2 and 30/60-1 patterns of the Humphrey Field Analyzer. The two monocular patterns, comprising 138 VF locations, were combined using the “best eye at location” approach. Reliable binocular VFs were available for 617 exams of 195 patients (aged 19 to 60 years) for up to 9 visits and 7.3 years of follow-up. Archetypal Analysis was used to decompose the binocular VF, finding representative features within the data. Based on the mean residual sums of squares, we used 12 archetypes. Each patient’s VF can be recovered from the combination of the 12 archetype patterns using a linear combination of that patient’s coefficients for each pattern. Linear mixed models, that account for repeated visits, investigated changes in archetype coefficients with age and heredity pattern, with random effects for subject and subject age.
The two figures show the corresponding 12 archetype patterns in our sample. All patterns were approximately mirror symmetric. Some patterns were variants of “tunnel vision” with different diameters and others included peripheral islands of residual vision. For the “tunnel vision” archetypes, the coefficients for #1, 2, and 7 increased with increasing age, but decreased with increasing age for #6. For the “peripheral island” archetypes, the coefficients for #4, 5 and 10 decreased with increasing age, but increased with increasing age for #9. Effects of hereditary pattern were less clear. Wide between-subject differences in the timing of VF loss were apparent.
This method of decomposing the binocular VF components provides insight into the functional vision available to patients with RP. As our scheme of components allows the quantitative decomposition of newly measured VFs, it allows for a more nuanced tracking of change over time than based on total area alone.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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