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Juthamat Witthayaweerasak, Ming-Hui Sun, Ali Shariati, Jennifer Li, Yaping Joyce Liao; Structure-Function Analysis in Chiasmal Compression Helps Predict Visual Prognosis. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4223.
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© ARVO (1962-2015); The Authors (2016-present)
Sellar mass compression of the optic chiasm is often an emergency, and there is a relative lack of data helping clinicians predict visual outcome. To address this problem, we performed structure-function correlation of spectral-domain optical coherence tomography and static automated perimetry in order to determine best predictors of outcome.
We performed a retrospective, cross sectional study of >100 patients with sellar mass at one institution from 2003 to 2015 and analyzed clinical characteristics and chronic, post-operative (range 3m-16y) paired perimetry and optical coherence tomography (OCT) measurements of retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC), which includes the ganglion cell and the inner plexiform layers. For statistical analysis, we used SPSS ver.20.
We performed post-operative structure-function correlation with 64 eyes in 33 patients. Despite the relatively good visual acuity (81% of eyes with 20/30 or better), persistent visual field loss was found in 61% (bi-temporal 42%, unilateral-temporal 18%). Retinal thinning as defined by OCT measurement at 5-percentile of normal was found in 45% of eyes per RNFL (mean 80.2±1.9 microns, 64 eyes) and in 55% of eyes per GCC (mean 69.5±1.5 microns, 62 eyes), consistent with irreversible retrograde degeneration. Using re-calculated visual field mean deviation and GCC (nasal=crossed, temporal=uncrossed), we best fit the structure-function correlation using formula: thickness = slope*100.1*(mean deviation in dB) + residual thickness. The temporal-superior field had residual thickness of 43-microns and the temporal-inferior field, 48-microns, consistent with chiasmal compression from below. Using ROC analysis, nasal GCC ≥55-micron significantly predicted good temporal visual field outcome (mean deviation better than -10 dB) (P<0.001, area under curve 0.914), with sensitivity and specificity of 89.1% and 93.7%. In 12 pre- and post-operative paired data, pre-operative GCC thickness ≥55-micron predicted good visual field outcome in 81.2% of patients, with significant post-operative visual field improvement (pre: -12.6±3.1 dB, post: -5.5±2.1 dB, P=0.01).
Timely treatment of severe optic chiasm compression can often lead to good visual outcome. A GCC thickness of ≥55 micron correlated with good post-operative visual outcome.
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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