Confusion between bitemporal hemianopia and cecocentral scotoma.

(()\li\l \()[ i()R Letters to the Editor contusion Between Bltemporel Itemlmopia and cecooentral sootonta saguona er al (I) reporml a case ofa 72-year-old woman with 20/200 visual acuity in both eyes from etharnbutol toxicity. They interpreted automated 2+2 visual ﬁeld studies as showing a hitern, al hemi- anopvia. Magnetic resonance images of the optic chiasm were described as showing hyperintense signal on T2-weighted images. As Glaser pointed out. ‘On occasion. bilateral ceco- central sctornas may mimic the bitentporal depression ofchiasmal interference&#39; (2). In this patient. a ceeoccn- rral scotoma is present. by definition. because the acuity is only 20/200. and there is conﬂuent ﬁeld loss between the blind spot and central ﬁxation. In a true temporal hemianopia. visual acuity is relatively preserved and the vertical rnidline it respected. Finaly. the magnetic images appear com- jonatltatt C. Horton. MD. PHD lkpanrwnu of Nrrrmhg. and Plyriabg. Uuirrrriry of (.&#39;¢lrﬁnu&#39;4. Saw I~‘nrnrr‘ra. San Fnmdrro. Crlrﬁmia Supported by National Eye Institute and Research to Prevent Blindness. The author reports no conﬂiets of interest. REERHOO 1. %W.9UDlK~QSKFIbH.§lr!ﬁmlRW| 1VIs comments. In addition to the numerous cases ofethamhutol-induced “tempo- ralhemianopiareportedinthepart.anirrralatutieshsvealso revealed t*iasmal affecting both the crossing and the mnerossirsguoru in experimentally induced ethtrnbutol tox- iciry (I). Kho et al (2) dtracteriuvl ed; q q““’e4 ‘iternporal hernianoph in a series of patients. and this study has shown the existence of bitemporal visual field defects with or without superimposed centrallcecooentral at tomm. and in those without tut. &#39; in; central or «eo- eenrral xotomas. the visual field defects were highly sug- gestive of ehiatrnal injury. Although a eecocentral seotoma mn___ - -lb‘, e awhhtu r IL - &#39;- che biteenporal visual ﬁeld defect in our use ,&#39;at.tsibly aligned along the vertical midline. and it is not confined to just the central portion of the temporal Selrls. We agree that the poor visual acuity in our patient cannot be plained the chiasmal lesion alone. and there may also be additional invohensent of the adjacent parts ofthe optic nerves as described previously in a histopathological study (I). But. this was not evident ratliognphically. 428 Magnetic resonance images (MRI) from our article were review:-d&#39; ap&#39;mlsyourneuroradtolo9st&#39; &#39; andalsoinaqrnas|tetl&#39; fashionbyjtxlterrreuroradiologistsuhohadnotuenthe irnap&#39;ng and were not aware ofthe case. These neuroradiol- ogistsreadilyandunanintotulyeonchrded that l)Iheon&#39;g‘nal MRI was clearly abnormal with increased T2 signal within thechiastnand\vasal.tomildlytwollert.antl2)thes&#39;gnIl intzeruity within the chiasrn norrnalited on the follow-up study. This imaging ﬁnding correlates with our patient’; L‘ I L ’ ’ r I Aron N. E Suodaran. MD. MSc. FIICPC Ilieharrl I. Path. MD. FIICPC Vivian 3. Output. 35:. MDCHE WAGS Toronto Warmr I-Iarpriral. Tenmro. Ontario. (loud: The authors report no eonﬂieta of interest 1. l.ﬂ0CI.H|ﬂoﬁl|%olOw0t\&#39;rIOmﬂ00IlVDWo| rntoocatton. had Ovhttrd-not Vii Sci. 1976:l$:76&709. 2. KDIC.N®%IM.klAIl\utraiMﬂl¢hbﬂl in ‘ q ‘ ‘ . WI)” W». 2011:31:12l—126. Ixﬂeil to II!’ Ethur I . 20/40; Sr!‘ 422-028 I \ \ i &#39;.J\l