Vol. 108/ No.4 Letters to the Journal 459

Fig. 2 (Scheider and Schroedel). Rarefaction of thesubfoveolar choroidal vessels in dry, age-relatedmacular degeneration. Arrow points to a venousloop.

es and a computerized image analysis of cho­roidal angiograms possible. Our resultsindicate a promising future for indocyaninegreen as a diagnostic dye for the detection ofchoroidal and also certain retinal abnormalitiesas well as for quantitative measuretnents of thechoroidal circulation.

References

1. Flower, R. W., and Hochheimer, B. F.: A clini­cal technique and apparatus for simultaneous angi­ography of the separate retinal and choroidal circula­tions. Invest. Ophthalmol. 12:248/ 1973.

2. Hochheimer, B. F., and D'Anna, S. A.: Angiog­raphy with new dyes. Exp. Eye Res. 27:1/ 1978.

3. Mainster, M. A., Timberlake, G. T., Webb,R. H., and Hughes, G. W.: Scanning laser ophthal­moscopy, clinical applications. Ophthalmology89:852/ 1982.

4. Nasemann, J.: Fluorescein angiography withthe scanning laser ophthalmoscope. First Interna­tional Symposium on Scanning Laser Ophthalmosco­py and Tomography, July 1989. In press.

Ocular Examination Schedule forInfants With Fetal Hydrops

Michael T. Trese, M.D.,and Daniel G. Batton, M.D.William Beaumont Hospital (M.T.T., D.G.B.), andDepartment of Ophthalmology, Kresge Eye Institute(M.T.T.).

Inquiries to Michael T. Trese, M.D., Associated RetinalConsultants, 3535 W. 13 Mile Road, Suite 507, RoyalOak, MI48072.

Premature infants who are born with hy­drops fetalis will have a birthweight considera­bly higher than what would be the norm fortheir gestational age. This birthweight maysuggest that the risk of retinopathy of prema­turity in such an infant is small. However, thechild' s dry weight is what should be used toestimate the risk of retinopathy of prematurityand therefore determine the ocular examina­tion schedule. Recently, a child who was theproduct of a 31-week gestation had hydropsand a birthweight of 1/840 g. Upon examinationeight weeks after birth and before leaving thehospital, the infant was found to have bilateralretinal detachments. After diuresis, the infant'slowest weight was 1/300 g. This child wasexamined according to the recommendations ofthe Retinopathy of Prematurity Study, and bythe time of examination had already developedretinal detachment.

It is the current practice in neonatal intensivecare units to log the birthweight without nota­tion as to hydrops. This case demonstrates thata child with hydrops should be especially notedin the intensive care unit log and be consideredfor an examination schedule for ocular exami­nations appropriate for a much lower birth­weight child. Thus, such children will be seenin a timely fashion for peripheral cryotherapyablation.

Isolated Abducens Nerve ParesisFrom Intrapontine, FascicularAbducens Nerve Injury

Lenworth N. Johnson, M.D.,and Robert S. Hepler, M.D.Neuro-Ophthalmology Division (L.N.J.), Penn StateUniversity Ophthalmology Department, Hershey;and the Neuro-Ophthalmology Division (R.S.H.),Jules Stein Eye Institute, UCLA School of Medicine,Los Angeles.

Inquiries to Lenworth N. Johnson, M.D., Neuro­Ophthalmology Division, Penn State University Ophthal­mology Department, Penn State University, Hershey, PA17033.

Isolated abducens nerve paresis withoutother neurologic signs is often attributed tovascular injury from hypertension, diabetesmellitus, or atherosclerosis.P The site of nerveinjury is thought to be within the subarachnoidspace or cavernous sinus, similar to vasculo­pathic oculomotor nerve palsy.v' Abducensnerve paresis from dysfunction of the intra-

460 AMERICAN JOURNAL OF OPHTHALMOLOGY October, 1989

pontine, abducens nerve fascicles is almostalways associated with other neurologic signs. 5

We encountered two cases of isolated, intra­pontine, fascicular abducens nerve paresis.

Case 1A 69-year-old woman was referred for evalu­

ation of horizontal diplopia of four weeks' du­ration. She was in good health without hyper­tension or diabetes mellitus. Results of theneurologic and neuro-ophthalmologic exami­nations were normal except for an isolated, leftabducens nerve paresis, with mild (20%) limi­tation of abduction. There was no restrictionevident on forced duction testing. Fasting andtwo-hour postprandial serum glucose, andWestergren sedimentation rate were normal.Magnetic resonance imaging, performed beforeour examination, showed increased signal in­tensity in the left midpons compatible withinfarction (Fig. 1). The abducens nerve paresisresolved three months after onset.

Case 2A 47-year-old man, with a history of hyper­

tension, was referred for evaluation of horizon-

Fig. 1 (Johnson and Hepler). Case 1. Increasedsignal intensity in the left mid pons (arrow) on T2­weighted magnetic resonance imaging compatiblewith infarction.

Fig. 2 (Johnson and Hepler). Case 2. Contrast­enhancing mass in the dorsomedial, left ponto­mesencephalic region (arrow) compatible with meta­static carcinoma.

tal diplopia of four weeks' duration. Fourmonths before the onset of the diplopia, he wasfound to have adenocarcinoma of the lung withmetastasis to the ischium. Results of neurologicand neuro-ophthalmologic examinations werenormal except for a left abducens nerve paresis,with mild (20%) limitation of abduction. Acomputed tomographic scan (Fig. 2) showed alarge (l em), contrast-enhancing mass in thedorsomedial, left pontomesencephalic regioncompatible with metastatic carcinoma. Cranialirradiation was instituted. The diplopia did notimprove.

Our two cases and that of Donaldson andRosenberg! indicate that isolated abducens pa­resis can occur from intra pontine disease. Thesite of injury may be extensive as in our Case 2,but hemiparesis, hemisensory deficit, and ves­tibular dysfunction are absent because of spar­ing of the corticospinal tract, medial lemniscus,and vestibular nuclei. Although structural ab­normality was documented in all cases, we donot recommend immediate radiologic studiesfor all isolated abducens palsies. Nerve ische­mia extrinsic to the brain parenchyma isthought to be the most common cause of isolat­ed abducens palsy. 1.2 Complete or partial reso­lution of the palsy usually occurs within one tofive months, with mean duration of threemonths.v' Thus, a reasonable approach for pa-

Vol. 108, No. 4 Letters to the Journal 461

tients suspected of having isolated, vasculo­pathic, abducens palsy without other neurolog­ic signs is periodic clinical examination. If thereare signs of improvement within three months,and no additional neurologic signs or symp­toms, then computed tomographic scan ormagnetic resonance imaging may not be essen­tial.

References

1. Rush, J. A., and Younge, B. R.: Paralysis ofcranial nerves III, IV, and VI. Cause and prognosis in1,000 cases. Arch. Ophthalmol. 99:76, 1981.

2. Galetta, S. L., and Smith, J. L.: Chronic isolatedsixth nerve palsies. Arch. Neurol. 46:79, 1989.

3. Weber, R. B., Daroff, R. B., and Mackey, E. A.:Pathology of oculomotor nerve palsy in diabetics.Neurology 20:835, 1970.

4. Savino, P. J., Hilliker, J. K, Casell, G. H., andSchatz, N. J.: Chronic sixth nerve palsies. Are theyreally harbingers of serious intracranial disease?Arch. Ophthalmol. 100:1442, 1982.

5. Donaldson, D., and Rosenberg, N. L.: Infarc­tion of abducens nerve fascicle as cause of isolatedsixth nerve palsy related to hypertension. Neurology38:1654, 1988.

Pupillary Dilatation with MonocularOcclusion as a Sign of NonorganicOculomotor Dysfunction

Nancy J. Newman, M.D.,and Simmons Lessell, M.D.Neuro-ophthalmology Unit, Massachusetts Eye andEar Infirmary, and Department of Ophthalmology,Harvard Medical School.

Inquiries to Nancy J. Newman, M.D., Neuro­ophthalmology Unit, Massachusetts Eyeand Ear Infirma­ry, 243 Charles si.. Boston, MA 02114.

Spasm of the near reflex, consisting of con­vergence, miosis, and accommodation, maymimic a sixth nerve paresis. I It occasionallyoccurs in intracranial and metabolic disorders."but generally is considered functional in ori­gin. I,3 The presence of signs of personalitydisorders, malingering, or hysteria combinedwith miosis on attempted horizontal gaze helpsconfirm the diagnosis of a functional oculardisturbance. We treated two patients with func­tional amblyopia and spasm of the near reflexwho demonstrated dramatic temporary rever-

sal of their pupillary miosis when either eyewas occluded.

Case 1A 41-year-old woman had bilateral visual

loss. Her medical history was notable for multi­ple miscarriages, an episode of depression re­quiring hospitalization at age 40, and mildangiohemophilia (von WiIlebrand's disease).For several months, she had been having head­aches when reading. One morning, after aparticularly severe headache the night before,she awoke with severe bilateral visual loss (nolight perception in the right eye, light percep­tion in the left). No abnormalities were foundon examination, and the diagnosis of "opticneuritis" was made. Computed tomographyresults were reported as normal. Her visionimproved only slightly over the next fourmonths, her headaches persisted, and shedeveloped photophobia.

Neuro-ophthalmic examination disclosed anormal-appearing woman who navigated theroom well but whose visual acuity measuredhand motions in the right eye and countingfingers at 8 inches in the left. Pupils werenormally reactive without a relative afferentdefect or pupillary escape. Her fundi wereunremarkable. Visual fields were tubular ontangent screen and spiral on Goldmann perim­etry. She had limited ocular abduction bilater­ally on attempted gaze to each side, alwaysaccompanied by miosis. Ductions were fullmonocularly. When asked to look into the dis­tance in the primary position, she remainedslightly esotropic with miotic pupils. However,when either eye was covered with an occluder,the visible pupil enlarged briskly.

Case 2A 23-year-old man complained: "My eyes

don't stay together... They go crisscross." Hismedical history was notable for "emotionalproblems and a learning disorder with a memo­ry problem," and he suffered from such severefear of public places that he never worked andwas considered totally disabled. A month be­fore our examination, polyopia developed andhe was referred to a neurologist who diagnosedan "eye muscle problem."

On neuro-ophthalmic examination, his best­corrected visual acuity was R.E.: 20/80 andL.E.: 20/60. Color vision (Ishihara plates) wasnormal, as were results of slit-lamp and fundusexaminations. Visual fields were spiral onGoldmann perimetry. Pupils were normally re­active and there was no relative afferent defector pupillary escape. Ductions were full, but