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Tobias Elze, Lucy Shen, Mengyu Wang, Michael V Boland, Sarah Wellik, C Gustavo De Moraes, Jonathan S Myers, Peter Bex, Louis R Pasquale; The effect of ametropia on glaucomatous visual field loss. Invest. Ophthalmol. Vis. Sci. 2016;57(12):No Pagination Specified. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To quantitatively compare visual field (VF) patterns of emmetropic and ametropic patients from 5 glaucoma practices to identify VF effects associated with refractive error.
The most recent reliable Humphrey VFs (fixation loss ≤ 33%, false negative/false positive rates ≤20%, SITA Standard 24-2) for each eye with spherical equivalent (SE) of refractive error between ±6D were selected from five clinical glaucoma practices and grouped by mean deviation (MD) into bins of ±1dB around 0dB, -4dB and -8dB. The pattern deviation (PD) values at each VF location were compared between emmetropes (SE: ±1D) and patients with different levels of SE by t-tests corrected for multiple comparison by false discovery rate. In addition, a statistical learning procedure called Mixture of Gaussian Clustering was applied to the PDs of emmetropes and myopes to identify and compare statistically optimal sets of representative VF patterns.
VFs from 18,581 emmetropic (SE: ±1D), 18,138 myopic (SE<-1D) and 14,157 hyperopic (SE>1D) eyes fulfilled the reliability criteria. A systematic effect of myopia on the location specific light sensitivity was found, with increased PD values in upper/nasal and decreased PD values in central/temporal/lower areas, as illustrated for the MD bin around 0 in Fig. 1. For most locations, the effect was opposite for hyperopes. The PD differences were significant for most VF locations for MD bins around 0 and -4dB and faded for MD bin around -8dB, as illustrated for myopes in Fig. 2A. For emmetropes, three VF defect patterns were found to optimally represent the VFs in our database (Fig. 2B). For myopes, an additional pattern was identified which precisely represents the differences from Fig. 1 and 2A. This myopia specific pattern, encircled in Fig. 2B, was present for lower SE values and for the MD bins around -4dB and -8dB as well.
We demonstrate a general and significant effect of SE on the pattern deviation values at specific locations of the Humphrey VF. The representative VF loss pattern identified in myopes may be independent of glaucomatous VF loss, as it was present in VFs of different MD values. Rather, it might be related to previously reported functional vision changes from retinal stretching. These findings create a framework for separating VF defects of ametropia from glaucomatous VF loss for better diagnosis and monitoring of glaucoma.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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