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Show }. Clin. Neuro-ophthalmo/. 4: 189-195. 1984. Visual Recovery Following Prolonged Amaurosis Due to Compressive Optic Neuropathy GERALD G. STRIPH, M.D. THOMAS L. SLAMOVITS, M.D. RONALD M. BURDE, M.D. Abstract A 2S-year·old white man presented with gradual right-sided visual loss over a 3-week period resulting in a visual acuity of "no light perception" in the affected eye for 5 days prior to presentation. Visual-evoked potential testing showed no re· sponse to light with the right eye and normal response with the left eye. Evaluation revealed an anterior communicating artery aneurysm compress· ing the right optic nerve. Eleven days following surgic.al decompression, 201200 vision was noted in the right eye; 2 months later, vision had improved to 20{30. Visual-evoked response testing postoperatively showed nearly complete return of function in comparison with the normal left eye. We believe this to be the first report of visual recovery follow· ing a prolonged absence of any "light perception" in a p.atient with compressive optic neuropathy. Compression of the anterior visual pathway is a common cause of visual dysfunction. 1 Prompt decompression frequently leads to significant recovery of vision. Prolonged compression is more likely to lead to irreversible visual loss. It is not likely that loss of visual function to the level of "no light perception" will improve after decompression. We are not aware of any reports of prolonged compressive visual loss leading to M no light perception" that reversed after decompression. We present the case of a 25-year-old man with gradual monocular visual loss deteriorating to Mno light perceptionM and persisting at that level for 12 days prior to surgical decompression of an aneurysm abutting his right optic nerve. Approx- From the (kpartments of Ophthalmology {TLS. CCSj and Neurology (TLS). UnivE.'rsity of Pittsburgh 5chool of Medicine. Pittsburgh. PE.'nnsylvania; and thE.' DE.'partments of Ophthalmology. Neurology. and Neurological Surgery (RMB). Wash· ington University School of Medicine. 5t. Louis. Missouri. September 1984 imately 11 days after surgery, visual function was present improving progressively to 20/30. Case Report In February 1980. a 25-year-old. right-handed white man was referred with progressive monocular visual loss in the right eye over a 3-week period. He was in good health until approximately 4 months prior to admission, when he suffered an unattended syncopal episode during a bowel movement. He claimed to be unconscious for about 30 minutes. Following this episode. he began to have occipital and bitemporal headaches. He continued to work, but was bothered with occasional periods of right-hand numbness and tingling. Three weeks prior to admission, his left eye was patched for 1 day following the removal of a small foreign body. When patched. he first noticed decreased visual acuity in his right eye. The vision in that eye steadily deteriorated, and for the 5 days prior to presentation, he felt that he had -no light perception" in his right eye. He had no history of diabetes, hypertension. collagen vascular disease. ophthalmologic disease. or known allergies to drugs or contrast materiaL Examination revealed the patient's visual acuity to be ·no light perception" in the right eye (when tested with an indirect ophthalmoscope set at maximum intensity) and 20/15 in the Jeft eye. On color vision testing of the left eye. he identified 10 of 15 American Optical pseudoisochromatic plates. External examination and ocular motility were normal bilaterally. Pupils were round and equal in size. Pupillary reactions to light were normal on the left and amaurotic on the right side. Kinetic perimetry (Goldmann) was normal on the left. Slit lamp examination revealed a small corneal stromal scar (left eye). but was otherwise normal. Applanation pressures and ophthalmoscopic examination were normal bilaterally. Visual-evoked response testing revealed no wave forms on the right and normal function IS' 190 (.) ,b) Figure I. Response of right eye IRE; left tracings) ilnd left eye (LE; right tracings) 10 4 Hz:55 mm (upper), 8 Hz:55 mm (middle), and 8 Hz:14 mm (lower). (II) Preo~ative VER recording demonstrating no response from right eye (visual aOlity. "no light perception") stimulation, and normal response (latt'ncy and amplitude) from left eye stimulation. (b) VER approximately 30 months after surgery demonstrating almost normal response from stimulation of the right eye, the visual acuity in which had improved 10 20/30. The left eye response remained normal. Journal of Clinical Neura-ophthalmology Striph, Slamovits, Butde Figutli' 2. cr scan showing suprasellar mass lesion. to photopic and checkerboard pattern stimulation on the left (Fig. 1). The remainder of the history and physical examination was unremarkable. A CT scan was obtained. Following injection of contrast material, the patient suffered an anaphylactic reaction complicated by significant hypotension requiring admission to the intensive care unit. The incomplete CT scan views suggested a mass lesion in the hypothalamic area (Fig. 2). On the 6th hospital day, following steroid pretreatment, the patient underwent cerebral angiography which showed a suprasellar aneurysm in the region of the anterior communicating artery (Fig. 3). On the 7th day of hospitalization, with vision on the right remaining at ~no light perception, ~ the patient underwent a left frontotemporal craniotomy with clipping of a giant aneurysm of the anterior communicating artery which was compressing the intracranial portion of the right optic nerve. Visual acuity after surgery remained at M no light perception~ in the amaurotic right eye and 20/15 in the left. On the 2nd postoperative day, he developed a left upper lid ptosis, and examination revealed a pupil-involving left third nerve palsy. The patient became lethargic. Repeat CT scan and arteriography were consistent with an extradural hemorrhage in the left temporal region; this was surgically evacuated on the 9th hospital day. During the 9 days follOWing his second operation, several visual acuity tests revealed ~no light perception~ on the right and normal acuity on the left. There was a persistent September 1984 pupil-involving left third nerve palsy which gradually improved. On the 18th hospital day (11 days after the aneurysmal dipping), the patient complained of binocular diplopia. Examination revealed visual acuities of 20/200 on the right and 20/20 on the left. On the 21st hospital day, acuities improved to 20/100 on the right and 20/20 on the left. There was a 2+/4 relative afferent pupillary defect on the right. Kinetic visual fields revealed a superotemporal quadrantic defect on the right and no abnormalities on the left (Fig. 4). He was discharged on the 23rd hospital day. Subsequently, his visual acuity, right visual field, and left oculomotor nerve function steadily improved. On examination 2 months postoperatively, he had a visual acuity of 20/30 in the right eye and 20/20 in the left. Pupils were reactive, but still unequal (3 mm on the right and 4 mm on the left), and there as a 1+/4+ relative afferent pupillary defect on the right. There was only a minimal ptosis and upgaze paresis on the left side, but not sugjective diplopia. Desaturation to brightness and redness testing was 25% on the right. Color vision testing with the American Optical pseudoisochromatic plates, revealed that he correctly identified 11/15 with his right and an 13/15 with his left. Ophthalmoscopic examination was normal except for temporal pallor of the right optic disc. The kinetic fields (Goldmann) showed further improvement in the I. and h isopters with a mild superotemporal relative defect on the right (Fig. 5). '9' Visual Recovery after Prolonged Amaurosis I • ,.2 Figur~ J. C~r~bT<1,1 angiogram {'lnterior "",wi showing Ih~ giant anterior communic.lting .Irtery .Ineurysm. filur~ 4. Ki"~ric vlsu.ll fidd (Goldnann perim~ter)of the right eye on th~ 13th postOJlftatin <by. Journal of Clinical Neuro-ophlhalmology Shiph, Siamovils, Burde Ficure 5. Kinetic visu,l field (Goldmann perimetry) of the right eye 2 months fol.lowinC surgery. He was again seen 21fl years postoperatively. Visual acuity at that time was 20/30 in the right eye and 20/15 in the left. Titmus and Randot testing showed nonnal stereoacuity. The mild anisocoria and relative afferent pupillary defect remained as did a slight deficit in upgaze on the left. Visual-evoked response testing was again perfonned. Bright flash testing produced good traces in both eyes; the traces from the right eye had slightly smaller amplitude as well as a small phase shift. Large checkerboard testing was normal for both eyes; small checkerboard testing demonstrated a slight delay in the traces stem+ ming from the right eye (Fig. 1). The patient has continued to do well. Discussion We believe that Thomas Hope's 1744 paper,l as cited by McDonald,J is the first report of visual recovery following the removal of a compression lesion in the case of an orbital tumor. Subsequently, many other authors, such as Kayan and Earl,4 describe visual loss and, following treatment, recovery from compressive lesions in the vicinity of the optic nerves or chiasm. Anterior visual pathway compression and vis~ ual loss are caused by a variety of lesions, com+ monly including pituitary tumors, craniopharyngiomas, meningiomas, and aneurysms.·... It appears that substantial recovery of vision can oc- Xoplember 1984 cur, and in the case of pituitary tumors does,' within 3 weeks of the surgery. Gregorius et a!.8 report loss and recovery of vision in patients with suprasellar meningiomas. Although they state that many of their patients experienced substantial visual acuity improvement postoperatively, the three patients who could not perceive light did not have any recovery of vision. Waybright et al.' report a series of patients with visual loss due to tumors compressing the optic nerve who frequently experienced visual improvement following surgery, even after several months of symptoms. However, in this series the four patients who could not perceive light preoperatively (the duration of this deficit ranging from 3 months to 15 years) remained blind. Pressure-induced change in nerve structure and function is being studied from the perspective of both clinical symptoms and histopathology.3 Several mechanisms for neural conduction defi+ cits are proposed to apply to compresSive neuropathy. 1 These include ischemia secondary to vascular compression, an interruption ofaxoplasmic flow, and direct damage to the neural or supporting tissues such as oligodendrocytes. Unless short+lived, blindness is pennanent following a major interruption of the vascular supply of the optic nerve. Therefore, in our case, the vascular mechanism of visual loss is not likely. Interference with axoplasmic flow in this patient is not supported by the fundus exam. No disc swelling 193 Visual Recovery after Prolonged Amaurosis or venous stasis is seen, even after a minimum of 5 weeks of compression. The relationship between inhibition ofaxoplasmic transport and neural conduction deficits is not clearly understood. Experimentally, myelin is known to be reversibly damaged by compression lO with functional return paralleling remyelination. ll The mechanism of conduction through partially or completely demyelinated nerve segments is unclear. 12 In an effort to understand the sometimes substantial visual recovery seen following surgical decompression of a tumor pressing upon the optic nerve, Clifford-Jones et al. 13 report creating an animal model of progressive chronic optic nerve compression by implanting an inflatable balloon near a eat's optic nerve. They state that at weekly intervals, the intraluminal pressure of the balloon was increased, thus simulating a slow-growing tumor. The contralateral optic nerve served as a control. Pathologically, the compressed nerves show prominent demyelination as early as 2 days after compression; however, after 5 weeks many axons were found to have a thin layer of myelin, postulated to be consistent with remyelination. Since remyelinated fibers have been shown to be able to transmit action potentials at physiologic rates,14·lS these workers propose that remyelinated fibers, which appear concomitantly with pressure-induced demyelination, playa role in the rapid recovery of vision following surgical decompression. Our patient's intracranial right optic nerve was compressed by an aneurysm, probably slowly expanding, leading to progressive visual loss. The mechanism of his optic neuropathy may thus have been quite similar to that proposed by Clifford-Jones. 13 In our patient, the postoperative visual-evoked response traces were similar in shape and conduction velocity for both eyes. The usual mechanism for conduction in myelinated nerves is saltatory. The normal left eye visual-evoked response results should represent this conduction mechanism. Postoperatively (Fig. 1), the visualevoked response from the right eye was slightly smaller in amplitude with greater latency than that recorded from left eye stimulation. The decrease in amplitude may reflect the loss of some neural tissue and may well be consistent with the optic atrophy seen in that eye. The increase in latency may be explained on the basis of purported demyelination and remyelination, but the normalcy of the right eye trace suggests a restoration of myelin-dependent saltatory conduction at that point in time. Conversely, McDonald3 divides recovery following relief of compression into two phases. First, he believes that rapid (i.e" within hours or days) recovery following decompression is due to 19. the reversal of ·physiologic block: analogous to the reversal of the sensation of a limb "going to sleep· when pressure is removed. His second proposed phase, occurring perhaps weeks later, is recovery due to restored conduction through remyelinated fibers and is compatible with that of Clifford-Jones. There is no evidence of a first phase recovery in our patient, but it may have gone unnoticed due to the severity of the more severe deficits of the remainder of the nerve and subsequent visual recovery dependent on progressive remyelination. The methods by which compression blocks neural conduction merit further study. Our patient was blinded by compressive optic neuropathy for 23 days; vision was first evident 11 days following decompression. The time frame of neural conduction deficit as shown by the inability to perceive light, does not seem to be consistent with ischemic or decreased axoplasmic now, as these theories are presently conceived. It is possible that the previously cited experimental theories of pressure-induced demyelination and remyelination may apply to this patient. The clinical examination and visual-evoked response results are not inconsistent with them. The factors which separate this patient from others who do not recover from blindness due to optic nerve compression are unclear, except that there is no evidence of permanent damage as witnessed by lack of clinically apparent nerve fiber bundle dropout. The upper time limit of recoverable visualloss due to compression is unknown, but the finding of a relatively normal optic nerve head on ophthalmoscopic examination can be considered a good prognostic sign. This case does provide hope for substantial visual recovery from damage induced by chronic compressive lesions of 3-4 weeks' duration. References I. Miller. N.R.: Walsh alld Hoyt's Clinical Neuro-ophthalmology. Vol. J (4th ed.). Williams & Wilkins, Baltimore, 1982, pp. 249-253; 284-288. 2. Hope, T.: An account of a remarkable cure performed on the eye of a young woman in Scotland. Phil. TrailS. Roy. Soc. umd. 43: 194-200, 1744. 3. McDonald. W.I.: The symptomatology of tumors of the anterior visual pathways. Call.]. Neurol. Sci. 9: 381-390,1982. 4. Kayan, A., and Earl, c.J.: Compressive lesions of the optic nerves and chiasm. Brain 98: 13-28, 1975. 5. ~hrens, M.M.: Neuroophthalmic aspects of orbital disease. In Clinical Ophthalmology, Vol. 2, T.O. Duane and E.A. Jaeger, Eds. Harper & Row, Philadelphia. 1983, chap. 29, pp. 7-9. 6. Huber. A.: Eyl' Symptoms ill Brain Tumors (2nd ed.). C.V. Mosby, 51. Louis, 1971, pp. 189-244. 7. Bakay, L.: The results of 300 pituitary adenoma operations. J. Neurosurg. 7: 240-255, 1950. Journal of Clinical Neuro-ophthalmology 8. Gregorius, F.K., Hepler, R.S., and Stem, W.E.: Loss and recovery of vision with suprasellar meningiomas. J. Nturosurg. 42: 69-75,1975. 9. Waybright, EA, Selhorst. j.B., Young. H.F., and Harbison, l.W.: Tumors compressing the optic nerve: Diagnosis and surgical results. VII. Mtd. 110: 230-234, 1983. 10. Ludwin, S.K.: Pathology of demyelination and remyelination. In Demyt'linaling Di~Q~: BQsic Qnd C/iniCllI Electrophysiology, S.C. Waxman, and j.M. Ritchie, Eds. Raven Press, New York, 1981, pp. 123-168. 11. Waxman, S.C.: Membranes, myelin, and the pathophysiology of multiple sclerosis. N. Engl. }. Mtd. 306: 1529-1532, 1982. 12. Sears, T.A., and Bostock, H.: Conduction failure in demyelination. 15 it inevitable? In Dtmyt'linating Di~a~: Basic Qnd (linielll Eltctrophysiology, S.C. Waxman, and j.M. Ritchie, Eds. Raven Press, New York, 1981, pp. 357-375. 13. Oifford-jones, R.E., Landon, D.N.. and McDonald, Septembl-r 1984 Striph, Slamovits, Burde W.I.: Remyelination during optic nerve compression.}. Neural. Sci. 46: 239-243, 1980. 14. Smith, K.J., Blakemore, W.F., and McDonald, W.I.: The restoration of conduction by central remyelination. BrQin 104: 383-404, 1981. 15. Smith, K.J., Blakemore, W.F., and McDonald, W.I.: Central remyeiination restores secure conduction. NQture 280: 395-396, 1979. Acknowledgment This work was supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York (Department of Ophthalmology, Washington University). Write for reprints to: Ronald M. Burde, M.D., Department of Ophthalmology-Box 8096, 660 South Euclid Avenue, St. louis, Missouri 63110. 195 |
