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Michael V Boland, In Ho Lee, David M Yousem, Neil R Miller; Quantitative analysis of the size and asymmetry of pituitary lesions and the associated visual field loss. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5859.
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© ARVO (1962-2015); The Authors (2016-present)
To understand the quantitative relationship between the size and asymmetry of pituitary tumors and the visual field loss they cause.
We identified patients who had magnetic resonance (MR) imaging with a diagnosis of pituitary macroadenoma who also had reliable visual field testing. Neuroradiologists reviewed all of the MR images to measure the displacement of the optic tract in the pre-chiasmal, chiasmal, and post-chiasmal regions. They also subjectively assessed the degree of right-left asymmetry in the tumor. To quantify the degree and laterality of visual field loss, we utilized algorithms previously developed for the Neurological Hemifield Test. In brief, we used the pointwise pattern deviation values from each visual field to assign a score proportional to the degree of vision loss loss at each point. These pointwise scores were then summed in each quadrant of the visual field. Each right-left pair of visual fields for each patient was summarized in terms of temporal field asymmetry (right temporal field minus left temporal field), the proportion of visual field loss that was temporal, total field asymmetry (all right eye minus all left eye), and total visual field damage (sum of all 4 fields in both eyes). These visual field metrics were then compared to either the maximum displacement of the optic tract or the tumor asymmetry on MR imaging.
Of the 114 subjects, 64 (56%) were male and the average age was 54.6 years. Both the summation of vision loss in both eyes and the proportion of visual field loss in the temporal hemifields were statistically significantly related to the maximum displacement of the optic tract (both p < 0.001 for fit of linear regression) - Figure 1. There was no statistical relationship between the subjective assignment of tumor asymmetry on MR imaging and either the asymmetry of temporal vision loss (R-L) or the asymmetry of total vision loss (R-L) (p > 0.05 by analysis of variance) - Figure 2.
As might be expected, the displacement of the optic tract by pituitary tumors is quantitatively associated with both the total amount of vision loss and the proportion of visual field loss that is temporal. Although there was right-left asymmetry of vision loss in some subjects, it was not related to the subjective assessment of asymmetry on MR imaging.
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