662 AMERICAN JOURNAL OF OPlITHALMOLOGY November, 1986

Examiner'sEye

Figure (Wisnicki and Guyton). The modified lightreflex text. The distance deviation can be estimatedfrom the eccentric reflex in the nonfixing eye, or thereflex can be centered with prisms.

from the patient (this distance is not critical). Apenlight is placed over the ruler at the markcorresponding to the patient's interpupillarydistance. The examiner then sights the positionof the corneal light reflex in the nonfixing eye,ignoring the position of the light reflex in thefixing eye. If the visual axes are essentiallyparallel, as they should be with distance fixa­tion, the visual axis of the nonfixing eye willcross the ruler exactly at the interpupillarydistance mark, and the nonfixing eye will ap­pear straight to the examiner. If a distancedeviation is present, the nonfixing eye will

References

1. von Noorden, G. K., and Maumenee, A. E.:Atlas of Strabismus, 3rd ed. St. Louis, C.V. Mosby,1967, p. 44.

2. Krimsky, E.: The Corneal Light Reflex. Spring­field, Illinois, Charles C Thomas, 1972.

3. Romano, P. E.: Optical aid for performingHirschberg and Krimsky tests at distance. J. Pediatr.Ophthalmol. Strabismus 10:208, 1973.

4. Krimsky, E.: Angular deviometer for 20-foottesting. Trans. Am. Acad. Ophthalmol. Otolaryngol.79:0P423, 1975.

5. --: A planar deviometer for near and fartesting. Trans. Am. Acad. Ophthalmol. Otolaryngol.79:0P422, 1975.

appear deviated. The displacement of the lightreflex from the center of the pupil correspondsto the distance deviation calculated as in thestandard Hirschberg test (Figure). Alternative­ly, the light reflex may be centered with hand­held prisms as in the Krimsky prism reflex test.

We find this maneuver easy to perform. It isparticularly useful in patients with poor fixa­tion in one eye, whether from amblyopia, cata­ract, vitreous hemorrhage, or other causes.Such patients give poor or variable responsesto cover testing. Because the strabismic devia­tion with distance fixation may be significantlydifferent from the Hirschberg or Krimsky mea­surement at near, a method for measurement ofthe distance deviation is needed. The distancelight reflex test can be used to estimate thedistance angle quickly and reliably.

Oscillopsia Associated With EyelidMyokymiaGregory B. Krohel, M.D.,and Paul N. Rosenberg, M.D.Department of Ophthalmology, Albany Medical Col­lege. This study was funded by an unrestricted grantfrom Research to Prevent Blindness, Inc.

Inquiries to Paul N. Rosenberg, M.D., Albany MedicalColiege, Dept. of Ophthalmology, New Scotland Ave.,Albany, NY 12208.

Eyelid myokymia is a common disorder thatoccurs in otherwise normal individuals. It usu­ally involves the orbicularis oculi of the lowereyelid on one side, although the upper eyelidsmay be involved as well. 1 Eyelid myokymia is

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Vol. 102, No.5 Letters to the Journal 663

thought to be aggravated by excessive fatigueor stress.P Many patients feel that their eye is"jumping" when they have orbicularis oculimyokymia. Vertical pseudonystagmus with os­cillopsia has been reported. 2 We recently exam­ined two ophthalmologists who both com­plained of horizontal oscillopsia induced bytransient myokymia of the lower eyelid. Bothpatients were aware of their myokymia andboth patients independently had been able toalleviate their oscillopsia by pulling the lowereyelids away from the eyes. Both indicated thatthey had been under some additional stressduring the period of eyelid myokymia. In bothinstances, the myokymia existed for severalmonths and then resolved spontaneously. Re­sults of complete neuro-ophthalmologic exami­nations were normal in both cases. One patientdrank tonic water containing quinine with norelief of his symptoms. Both patients recoveredin several weeks after being reassured thattheir oscilliopsia and pseudonystagmus werenot pathologic. One patient had also stoppedthe use of moderate amounts of caffeine fourdays before the myokymia resolved.

Uniocular pseudonystagmus secondary toeyelid myokymia has been reported.P In oneinstance, the pseudonystagmus noted was ver­tical and evoked oscillopsia and nausea," Thenausea was thought to be secondary to com­pression of the globe by the fasciculating eye­lid. Both of our patients were able to relieve theoscillopsia by pulling the eyelid away from theglobe. The pseudonystagmus could be seen onslit-lamp examination as a very high velocityhorizontal nystagmus that coincided with theeyelid fasciculations.

Eyelid myokymia is common, whereas thecomplaint of oscillopsia associated with thisproblem is much less frequently reported. Onemight speculate that the amplitude of the eye­lid fasciculations determines whether or notthe patient will experience oscillopsia. Oph­thalmologists should be aware of this syn­drome, as neurologic examination in the ab­sence of any facial myokymia is unwarranted.Reassurance alone will often be curative. Wealso suggest cessation of caffeinated products.

References

1. Miller, N. R. (ed.): Walsh and Hoyt's ClinicalOphthalmology, 4th ed. Baltimore, Williams andWilkins, 1985, p. 980.

2. Reinecke, R. D.: Translated myokymia of thelower eyelid causing uniocular vertical pseudonys­tagmus. Am. J. Ophthalmol. 73:150, 1973.

Contact Lens Scalpel for IntraocularSurgeryFumitaka Ando, M.D.,Jay 1. Federman, M.D.,Norio Daikunzono, M.Sc.,and John Osborn, M.Sc.Department of Ophthalmology, National NagoyaHospital (F.A. and N.D.), and the Retina Service,Wills Eye Hospital (J.L.F. and J.O.).

Inquiries to Jay L. Federman, M.D., Wills Eye Hospital,Ninth and Walnut Sts., Philadelphia, PA 19107.

Most ophthalmic photocoagulation instru­ments utilize laser energy sources. With non­contact systems the laser energy penetrates thetissue deeply, resulting in unfavorable damageto adjacent structures. To avoid this disadvan­tage, a contact laser scalpel that uses an artifi­cial sapphire! has been developed.

The laser tip is made of a single artificialsapphire crystal of AbOg, which transmits theNd:YAG laser beam well. The laser energy isfocused at the distal end of the laser tip by theshape of the tapered conical portion. Becauseof the large divergence of the beam emittedfrom the laser tip, the power density decreasesrapidly as the distance between the end of thetip and the tissue surface increases.

The conical contact laser tip made of artificialsapphire can be used as a scalpel to cut intraoc­ular tissue without causing bleeding. Themechanism of incision is considered to be va­porization, carbonization, and coagulation. 1 Inour initial studies on the rabbit, the laser scal­pel was connected to a conventional opticalquartz fiber of a Nd:YAG laser system: a xenonlamp was used as an aiming light.

The histologic section of the rabbit eye thatwas enucleated about three hours after applica­tion of the contact laser scalpel is shown inFigure 1. The power of the Nd:YAG laser was 2Wi the laser tip was in contact with the surfaceof the normal attached retina. A conical shapedtip with a fine point of approximately 400 IJ.mwas used. The retina and the choroid wereincised without bleeding and without the de­velopment of an immediate adhesion. Howev­er, an area beneath the incised retina and cho-