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Show Fourth Nerve Palsy Opposite a Black Eye To the Editllf: AlthlHlgh I prrsl't1.1Ily h.lVe l1l't h.ld the opportunity tll review such .1 c.be, I re.ld Dr. Ke.lI1l"s Jrtide in till' "'urn.11 with lllnsider.lble intefl'st. I wlluld whtllehe.lrtedly .lgrel' with his discussion .llld in p.lrticul.H, his thlHlghts concerning thllse Whll .1l!Vllc.lte e.Hl" surgic.ll repJir llf orbitJI floor biLlwllut fr.Ktures. This pJrticul.H subject h.1S been recentl" reviewed in our stJte medicJI journ.ll, t .llld h.ls sp.u\...ed consider.lble 1001 controversy. Withtlut perStlll.llly examining the two patients presented in Dr. KeJne's article or having available the dJt.l from .m orthoptic evaluation, one can not find fault with the c1inicJI diagnosis that Dr. Keane has m.lde. Upon close scrutiny of the photographs provided, however, one has to question the diagnosis of an isolated left IV nerve palsy (case 2 more than case 1). Although the debate may be academic, your readers may find such a discussion instructive. Recall that although we customarily check Letters to the Editoro .lppr('ci.lte th'lt .1 difference exists. With apparently norm.ll downg.lze of the right eye, this patient has not l'nly -4 undnJction of the left SO but also -,3 to -4 under,lction of the left IR: a "double depressl1r p.HJlysis," if you will. A similar but less definite present.ltillll is suggested in Figure I. Although .1 Knapp type IV 50 palsy can give <I simil.H appear.mce, I would doubt th<lt this is <I possibility q days after injUry. Occ<lsionally, with a unilateral 50 pJlsy, one sees an overaction of the contralateral 50. If the patient then fixates with the nonparetic eye, a simulated lR paresis of the paretic eye is presented. This possibility also does not appear to be the case with this patient. With a history of head trauma, the possibility of a basilar skull fracture, stupor at presentation, and bilateral horizontal and vertical gaze-evoked nystagmus, such a "double depressor p<lralysis" might suggest the possibility of a skew deviation. A much less likely alternative would be a monocular downg< lze paresis. In summary, close scrutiny of the photographs provided by Dr. Keane suggests that Figure 1. A 22-ve"r-llld w,'m"n With tr"Um,ltlc left IV nerve p.ll,v. N"te the under,ld,,'n (-.~) llf the left -"penl'r l,bl'llue \\'Ith normal left 'nfenor rectu~ fumtlon superior oblique (SO) function in down and in gaze, the primary depressor of the globe is actually the inferior rectus (lR). Cert<linly in abduction where the IR has its greatest effect as a depressor, the SO contributes little, if any, as a depressor. Hence, an isolated SO palsy should not limit depression in abduction. In the accompanying figure, a patient with .1 traumatic left IV nerve palsy is presented. Note the limited depression in <ldduction of the left eye (= -3 underaction of left SO) but normal depression in abduction (= norm<ll IR function). This is the presentation th<lt one would expect in J IV nerve palsy of recent onset. If one compares this patient with Figure 2 in Dr. Ke<lne's article, one can re.ldily June 1982 there is "more th.ll1 wh.lt meets the eye" here than just an isol.lted IV Ilerve p.llsy. This wtluld tend to reinforce Wh.lt h.1S .llre,ldy been mentitlned~ concerning the difficulty occlsion.llly enclluntered in m.lking the di.lgnosis llf .1 supcrit'r llblique p.llsy W.lyne W. Hixenm.IJ1, M.D. Tucson, Arizl"l,l References I. Bixl'l1l1l,lI1, W. W.: l hbit.ll fllll'r "blllWllut" fr ~cturl'~- C1il1il',ll M.lI1,lgCl1ll'l1t. Ariz. MeJ. 38(8): l,21, l°tll. 2. BixCl1l1l.ll1, W.W.: ()i.lgno~i5 t,f superior oblique p.ll~y. /. elin. Neufll-lll'hth.l/nwi. 1(3): 199, 1981. 141 |