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Show J. Clin. Nellro-ophthalmol. 5: 149-152, 1985 © 1985 Raven Press, New York Periodic Alternating Nystagmus Clearing After Cataract Surgery WALTER M. JAY, M.D. BRADLEY B. WILLIAMS, M.D. ALBERT DE CHICCHIS, Ph.D. Abstract A 60-year-old man developed periodic alternating nystagmus in association with decreased vision due to cataracts. Prior to surgery, vision was limited to hand motion only in both eyes. An extracapsular cataract extraction with insertion of a posterior chamber intraocular lens was performed in the patient's left eye. On the first postoperative day, vision was 20/60 in the left eye and the nystagmus was absent with both eyes open. Periodic alternating nystagmus that occurs with poor vision is related to a loss of fixation. Surgery aimed at improving the visual status may be effective in extinguishing the nystagmus. Periodic alternating nystagmus is a horizontal jerk nystagmus that cyclically reverses direction. It characteristically exhibits a fast phase beating in one direction followed by a nystagmus- free phase, after which the fast phase beats in the opposite direction. The duration of the two major phases may vary considerably and may be asymmetric. l Daroff and Dell'Osso2 reported that the cyclical nature of periodic alternating nystagmus could be explained by periodic shifts of the null region. Periodic alternating nystagmus may be congenital or acquired. Conditions associated with acquired periodic alternating nystagmus include head trauma, vascular insufficiency, encephalitis, syphilis, multiple sclerosis, spinocerebellar degeneration, posterior fossa tumors, cranial cervical junction abnormalities, blindness, and anticonvulsant intoxication. l .3,4 In 1983, Cross et aJ.5 reported the case of a 54-year-old man who developed periodic alter- From the Departments of Ophthalmology (W.M.J., B.B.W.) and Audiology and Speech Pathology (A.D.), Veterans Administration Medical Center and Medical College of Georgia, Augusta, Georgia. Write for reprints to: W. M. Jay, M.D., Ophthalmology Section (112), Veterans Administration Medical Center, Augusta, GA 30910, U.S.A. September 1985 nating nystagmus following a subarachnoid hemorrhage complicated by bilateral vitreous hemorrhages (Terson's syndrome). The patient's visual acuity was light perception in both eyes. After a vitrectomy was performed in the patient's right eye, visual acuity returned to 20/ 400 and the nystagmus was no longer clinically evident with the right eye fixing. We describe a 60-year-old black man who developed periodic alternating nystagmus as his vision deteriorated because of cataracts. After extracapsular cataract surgery and the insertion of a posterior chamber intraocular lens, the nystagmus cleared. Case Report J.I., a 60-year-old black man, was admitted to the Medical College of Georgia Hospital on September 19, 1984. His vision was limited to hand motion only in both eyes secondary to bilateral dense white cataracts. He reported a progressive bilateral loss of vision over several vears. Prior to this, he had good and equal vision in both eyes, The past ocular history was unremarkable. His wife stated that when his vision deteriorated, his eyes began to "jiggle." This "jiggling" had been present for approximately 2 years. The patient had a history of a right cerebral hemorrhage in May 1976, with minimal residual deficits. He had a single seizure in 1978 and was treated for 6 years with Dilantin, 200 mg g.h.s., during which time he was free of seizures. In July 1984, a Dilantin bll)od level l)f 2.5 f.Lg/ml (therapeutic range, 10-20 f.Lg/ml) was obtained. This being subtherapeutic, the Dilantin was discontinued and the patient continued to be free of seizures. The patil'nt had a past history of alcohol abuse, with micronodular cirrhosis diagnosed by liver biopsy in May 1984. In July 1984, he was admitted for a bone marrow biopsy with results consistent with a monoclonal gammopathy, On ocular examination, best corrected visual 149 PeriodiL' Alternating Nystagmus elL-Ming acuity was hand motion only in both eyes. Eye movement l'valuation revealed a horizontal jerk nystagmus that periodically changed directions. A typical cycle would be a 20-30 s fast phase in Olll' direction, followl'd by a 2-5 s nystagmusfree period, followed by a 20-30 s fast phase in the oppositt' horizontal direction. Pupillary examination was normal, with no afferent pupillarv defect. A 25 prism diopter alternating exotropia was noted. Intraocular pressures were 13 mm Hg on the right and 14 mm Hg on the left. Slit-lamp examination revealed a clear cornea and a normal anterior chamber depth. Bilateral, dense white cataracts were present. The fundus could not be seen because of the cataracts. Bscan ultrasonography of both eyes revealed no evidence of a retinal detachment or tumor. Prior to surgery, a computed tomographic scan of the brain and orbits with enhancement was performed that revealed cortical atrophy. On the day following admission, the patient underwent extracapsular cataract surgery in the left eye and a posterior chamber intraocular lens was inserted. On the first postoperative day, visual acuity in the left eye was 20/60. Nystagmus was no longer present with both eyes open. Two months postoperatively, vision in the left eye was 20/30 at distance uncorrected. Nystagmus was absent. On April 24, 1985, the patient underwent extracapsular cataract surgery in the right eye and a posterior chamber intraocular lens was inserted. In May 1985, visual acuity was 20/40 in the right eye and 20/30 in the left eye. Nystagmus was absent. Eye Movement Recordings Electronystagmographic recordings were made using a Tracoustics RN-260 electronystagmograph recorder. Bitemporal recordings of horizontal nystagmus were obtained by attaching surface electrodes to the outer canthus of both eyes and placing a ground electrode on the patient's forehead. Electrode impedance was less than 10,000 ohm. Nystagmus was recorded on the instrument's own strip chart recorder, which utilized a heat stylus. Recording speed was 10 mm/s. Preoperative bitemporal alternating current recordings were obtained with the patient seated upright in a chair in a dimly lit room. Because of the patient's poor vision (hand motion only), a calibrated recording could not be obtained. Figure 1 shows a typical cycle of periodic alternating nystagmus. Note that occasionally there is an increasing slow phase velocity. Bitemporal direct current recordings were made postoperatively. The patient was seated 150 upright in a dimly lit room approximately 6 ft from a light bar. The electronystagmographic recording was calibrated such that one degree of eye movement represented 1 mm of pen deflection. Bitemporal recordings were obtained with both eyes open and uncovered while the patient fixated on a dot at center position on the light bar. No nystagmus was noted in this cond ition. Bi temporal recordings were then obtained while the left eye was covered with a + 30 diopter lens. By reducing the patient's ability to fixate, periodic alternating nystagmus was again noted (Fig. 2). As in the preoperative recording, there was occasionally an increasing slow phase velocity. In an effort to document that the increasing velocity slow phase pattern was not related to our recording procedure, direct current optokinetic recordings were obtained. The results showed a linear sawtooth, slow phase pattern. Postoperatively, periodic alternating nystagmus was recorded on four separate occasions when the left eve was covered with a + 30 diopter lens (September 21 and 28, and October 12 and 26, 1984). On a fifth occasion (April 23, 1985), approximately 7 months postoperatively, no nystagmus could be recorded when the left eye was covered with a + 30 diopter lens. Discussion The effect of fixation on periodic alternating nystagmus is variable. Baloh et a1. 6 studied three cases of periodic alternating nystagmus in detail with digital computer methods to quantify and graphically display their electronystagmographic recordings. In the first patient, nystagmus developed only with eve closure, in the dark, or with a + 30 diopte'r lenses. In the second patient, nystagmus occurred only with attempted fixation and disappeared with loss of tixation. In the third patient, the nystagmus was not altered bv the presence or absence of fixation. In our patient, by history, periodic alternating nysta~mus developed concomitantly with the loss at vision due to cataracts. Prior to surgery, our patient exhibited poor fixation, having only hand motion vision. By restoring fixation with cataract surgery, the nystagmus cleared. The loss of fixation which occurred with cataract development did not cause, but simply made mamtest, a previously latent periodic alternating nystagmus. If loss of fixation alone were responsible, all patients with dense bilateral cataracts would exhibit periodic alternating nystagmus, which is obviously not the case. Yee et aI.? reported the case of a patient in whom monocular nystagmus disappeared after Journal of Clinical Neuro-ophthalmology Jay el al. iL, ••c Figure 1. Prt'opt'rativt' bitt'mporal ,lltt'rnatin~ currt'nt rt'cordings of pt'ril1dic altt'rnatin~ nystagmus. Tht' nysta~mus was rt'cordt'd in a dimIv lit ro,lm with both t'\'t's opt'n. Tht' patit'nt's vision was hand mll!illn ,,,,Iv in both "\·t's. Ri~ht is up .1I1d d,,,\'n is Idt. cataract surgery. The patient had a mature, presenile cataract of the left eye and vertical uniocular nystagmus with onset of visual loss in adulthood. After cataract surgery and aphakic correction with a contact lens in the left eye, the nystagmus was no longer present. In our patient, the periodic alternating nystagmus did not exhibit the typical cycle length of 90 s of fast phase in one direction, a null period, and 90 s of fast phase in the opposite direction. This type is more often seen when an underlying brainstem disorder is responsible. The shorter cycle time, as well as the occasionally increasing slow phase velocity noted on eye movement recordings,8 would point to the presence of a latent congenital periodic alternating nystagmus. Miller9 has postulated that patients with periodic alternating nystagmus whose nystagmus disappears when vision is restored may have a congenital abnormality in brainstem and cerebellar circuitry. This abnormality could produce inherent instability of the eyes that is of no clinical significance as long as there are normal retinal signals relayed to the brainstem and cerebellum. Once these signals are interrupted, however, the intracranial anomaly re-suIts in ocular instability and periodic alternating nystagmus develops. In our patient, when the operated eye was covered with a + 30 diopter lens, the periodic alternating nystagmus recurred during the first 2 months postoperatively. At 7 months postoperatively, however, no nystagmus was present when the left eye was covered with a +30 diopter lens. Halmagyi et al. lO treated three patients exhibiting periodic alternating nystagmus with baclofen. They noted that this therapy was effective in treating two patients with the acquired type of the disorder but was ineffective in another patient with the congenital type. Campbell~ described a 47-year-old alcoholic man who developed periodic alternating nystagmus with Oilantin intoxication. Our patient also had a history of chronic alcoholism and Oilantin therapy. However, in our patient, a Oilantin blood level was noted to be subtherapeutic and the medicine was discontinued 2 months prior to the surgery. Our case and the case previously described by Cross et aI." suggest that periodic alternating nystagmus associated with low vision is related Figure 2. Postoperative bitemporal direct current recordings of periodic alternating nystagmus. The nystagmus was recorded with the patient seated upright in a dimly lit room and with the left operated eye covered with a + 30 diopter lens. The recording was calibrated such that 10 degrees of eye movement represents 10 mm of pen deflection. Right is up and down is left. iL1sec September 1985 151 Periodic Alternating Nystagmus Clearing to a loss of fixati:Jn. Surgery to improve the visual status may be effective in extinguishing the nystagmus. References 1. Oostervcld, W. j., and Rildemakers, W. j. A. c.: Nystagmus alternans. Acla Ololaryllxol. 87: 404.. J09, 1979. , Daroff, R. S., and Dell'Osso, L. F.: Periodic altl'rnating nystagmus and the shifting null. Call. I· Ulolaryngo/. 3: 367-371, 1974. 3. Davis, D. C., and Smith, j. L.: Periodic alternating nystagmus. Alii. I. Ophtlmllllol. 72: 757762, 1971. ..J. Campbell, W. W.: Periodic alternating nystagmus in phenytoin intoxication. Arch. Neurol. 37: 178-180, 1980. 152 5. Cross, S. A., Smith, J. L., and Norton, E. W. D.: Periodic alternating nystagmus dearing after vitrectomy. f. Gin. Neuro-ophlhalmol. 2: 5-11, 1982. 6. Baloh, R. W., Honrubia, V., and Konrad, H. R.: Periodic alternating nystagmus. Brain 99: 11-26, 1976. 7. Yee, R. D., Jelks, c. W., Saloh, R. W., et al.: Uniocular nystagmus in monocular visual loss. Ophthalmology 86: 511-518, 1979. 8. Leigh, R. j., and Zee, D. S.: The Neurology of Eye MOUCn/Cllls F. A. Davis Co., Philadelphia, 1983, pp. 202-203 9. Miller, N. R.: Walsh and Hoyt's Clinical Neuro-OphIhall1lology, Vo/. 2. Williams & Wilkins, Baltimore, 1984, pp. 903-905. 10. Halmagyi, C. M., Rudge, P., cresty, M. A., et al.: Treatment of periodic alternating nystagmus. Ann. Neural. 8: 609-611, 1980. Journal of Clinical Neuro-ophthalmology |