lium was noted at the nasal edge of the fovea (Figure 1).Intravenous fluorescein angiography of the right eye wasunremarkable and in the left eye, demonstrated mottledwindow-defect type hyperfluoresence in the nasal mac-ula (Figure 2).

The laser-pointing device to which this patient was

exposed had a maximum power rating of 5 mW (US Foodand Drug Administration class IIIa laser) with a 670-nmwavelength (Apollo Audio Visual Model MP-1600,Ronkonkoma, New York). Operational instructions pack-aged with the device included a warning stating, “Do notstare into the laser beam. Do not direct the beam toward aperson’s eyes.” Affixed to the side of the device itself wasan additional warning label stating, “Laser light—Avoiddirect eye exposure.”

Most cases of laser-induced retinal injury result fromaccidental exposure to high-energy class IV lasers withmilitary, laboratory, or medical applications.1 Usedappropriately, low-energy class IIIa laser devices poselittle risk of retinal injury.2 Consequently, reports ofsuch low-energy laser devices causing retinal injury arerare.3 Two factors may have contributed to the devel-opment of the macular lesion noted in this patient.First, racial fundus pigmentation may have increasedabsorption of the laser energy at the level of the retinalpigment epithelium and choroid, accentuating the ef-fect of the low-power laser.4 Second, the effect ofprolonged intentional self-exposure of the patient’s eyeto the laser beam may have played a more importantrole. The findings in this case emphasize the importanceof cautious and appropriate use of low-energy class IIIalaser devices. Misuse and failure to heed safety recom-mendations may result in retinal injury.

REFERENCES

1. Wolfe JA. Laser retinal injury. Mil Med 1985;150:177–185.2. United States Code of Federal Regulations. Title 21, chapter

1, part 1040, section 1040.10;1995:522–535.3. Chen TL, Yang KR, Chen SM. Photic maculopathy by low

energy laser beam: a case report. Chang Keng I Hsueh1994;14:273–277.

4. Smiddy WE, Fine SL, Green WR, Glaser BM. Clinicopatho-logic correlation of krypton red, argon blue-green, and argongreen laser photocoagulation in the human fundus. Retina1984;4:15–21.

Idiopathic Giant Retinal Tears inIdentical TwinsNauman A. Chaudhry, MD,Harry W. Flynn, Jr, MD, andHomayoun Tabandeh, MD

PURPOSE: To report idiopathic unilateral giant retinaltears with retinal detachment in identical twins thatoccurred 2 weeks apart.

Accepted for publication July 9, 1998.From the Department of Ophthalmology, Bascom Palmer Eye Institute,

University of Miami School of Medicine, Miami, Florida.Inquires to Harry W. Flynn, Jr, MD, Bascom Palmer Eye Institute, 900

NW 17th St, University of Miami School of Medicine, Miami, FL 33136;fax: (305) 326-6417.

FIGURE 1. Red-free fundus photograph of the patient’s left eye 2days after prolonged gazing into beam of class IIIa laser-pointingdevice. Note focal lesion at level of retinal pigment epithelium innasal macula (arrow).

FIGURE 2. Intravenous fundus fluorescein angiogram of thepatient’s left eye demonstrates window-defect type hyperflu-oresence in nasal macula (arrow) after exposure to beam oflaser pointer 2 days earlier.

AMERICAN JOURNAL OF OPHTHALMOLOGY96 JANUARY 1999

METHODS: Case reports.RESULTS: In both patients, giant retinal tear and retinaldetachment was treated with pars plana vitrectomy,placement of encircling scleral buckle, fluid-perfluoro-carbon exchange, endolaser treatment, perfluorocarbon-air exchange, and 16% perfluoropropane injection. Oneyear after retinal detachment surgery, cataract developedin both postoperative eyes. Phacoemulsification withposterior chamber intraocular lens implantation was per-formed on both eyes. Three and a half years after retinalsurgery, corrected visual acuity in both treated eyes was20/20, and retinal reattachment was successful.CONCLUSIONS: To our knowledge, this is the first reportof idiopathic giant retinal tears in identical twins andraises the issue of genetic influences in the pathogenesisof this disease. (Am J Ophthalmol 1999;127:96–99.© 1999 by Elsevier Science Inc. All rights reserved.)

MODERN VITREORETINAL SURGICAL TECHNIQUES, IN-

cluding the use of perfluorocarbon liquids, havesignificantly improved the outcome of treatment for giantretinal tears.1 Although there have been reports of familialidiopathic giant tears,2,3 we describe the occurrence ofidiopathic giant tears that developed within 2 weeks inidentical twins.

A 40-year-old woman presented in 1994 with a 1-weekhistory of decreased vision in her left eye. She denied anyhistory of trauma. Medical and ocular histories wereunremarkable, and there was no family history of retinaldetachment. Corrected visual acuity was RE, 20/20 andLE, 20/70. Refraction was RE, 21.00 10.50 3 90 and LE,20.75 sph. The anterior segment examination showedclear lenses in both eyes. The posterior segment examina-tion of the right eye was normal, but the left eye disclosedposterior vitreous detachment and a temporal retinaldetachment with giant retinal tear extending from the1-o’clock to 5-o’clock positions (Figure 1). The patientunderwent pars plana vitrectomy, placement of encirclingscleral buckle, fluid-perfluorocarbon exchange, endolasertreatment, perfluorocarbon-air exchange, and injection of16% perfluoropropane gas. At 1 year after surgery, shedeveloped a progressive nuclear sclerotic cataract in theleft eye and had phacoemulsification with posterior cham-ber intraocular lens implantation. At 3.5 years after retinalsurgery, corrected visual acuity was LE, 20/20, and theretina was attached.

Two weeks after we operated on the first twin, her twinsister presented with acute onset of floaters in the right eye.Her medical and ocular histories were unremarkable, andthere was no history of trauma. Corrected visual acuity was

FIGURE 1. Giant retinal tear (arrows) with retinal detachment (arrowheads) in the left eye of the first twin.

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BE, 20/20. Refraction was RE, 20.75 10.50 3 80 and LE,21.00 10.25 3 90. The posterior segment examination ofthe right eye showed a temporal retinal detachment with agiant retinal tear extending from the 8-o’clock to 12-o’clock positions (Figure 2). A posterior vitreous detach-ment was also noted. At the time of surgery, the posterioredge of the tear was rolled over with extension of thedetachment. Pars plana vitrectomy, placement of encirclingscleral buckle, fluid-perfluorocarbon exchange, endolasertreatment, perfluorocarbon-air exchange, and injection of

16% perfluoropropane gas was performed. At 12 months,the patient developed cataract in the treated eyeand underwent phacoemulsification and posterior chamberintraocular lens implantation. At 3.5 years after retinalsurgery, corrected visual acuity in the right eye was 20/20with attached retina.

The most common category of giant retinal tears isidiopathic.2 Reported associations with giant retinal tearsinclude trauma, high myopia, Wagner-Stickler syndrome,Marfan syndrome, and nasal coloboma of the lens.4 Giant

FIGURE 2. Giant retinal tear with retinal detachment in the right eye of the second twin.

TABLE. Important Clinical Differences Between Retinal Dialysis and Giant Retinal Tear

Retinal Dialysis Giant Retinal Tear

Size Variable Equal or greater than 3 clock hours

Location At or slightly posterior to ora serrata At or posterior to the posterior margin of

vitreous base

Relationship to vitreous base* Posterior edge of the break attached to

the vitreous base

Free posterior edge; anterior edge attached

to the vitreous base

Posterior vitreous detachment Usually absent Usually present

*Can be observed with slit-lamp biomicroscopy.

Modified from Hagler.5

AMERICAN JOURNAL OF OPHTHALMOLOGY98 JANUARY 1999

tears may also occur at the posterior edge of chorioretinaldegeneration or along the posterior edge of excessivetreatment with cryotherapy, diathermy, or photocoagula-tion.

Hagler5 noted the frequent difficulty in distinguishingbetween giant retinal tears and retinal dialyses. The Tabledescribes the general differences between the two condi-tions. Both our patients had true giant retinal tears withposterior vitreous detachments. Furthermore, the absenceof high myopia and absence of known hereditary vitreo-retinopathy support the diagnosis of idiopathic giant tearsin our patients.

The role of hereditary factors in the pathogenesis ofretinal detachment including those from giant retinal tearsis uncertain.3,5,6 McNeil and Mcpherson3 described aTexan family with retinal detachment and giant retinaltears. In this study, 31 individuals had retinal detachmentin a family of 181 members over five generations, but theexact number of patients with giant retinal tears was notmentioned. The proposed mode of inheritance was auto-somal dominant with variable penetrance. Schepens2 alsoreported siblings with bilateral giant tears. Similarly, Fran-cois6 published cases of familial retinal dialysis with vari-able inheritance. Hagler5 reviewed all reported cases offamilial retinal dialysis and concluded that heredity wasnot a notable factor. To our knowledge, this is the firstreport of identical twins with idiopathic giant tears, and itraises the issue of hereditary influences in the pathogenesisof these tears.

REFERENCES

1. Chang S, Lincoff H, Zimmerman NJ, Fuchs W. Giant retinaltears: surgical techniques and results using perfluorocarbonliquids. Arch Ophthalmol 1989;107:761–766.

2. Schepens CL. Retinal detachment and allied diseases. Volume2. Philadelphia: WB Saunders Co, 1983:520–565.

3. McNiel NA, McPherson A. The inheritance of detachedretina in a Texas family. J Hered 1971;62:73–77.

4. Wilkinson CP, Rice T. Michels retinal detachment. St Louis:CV Mosby Co, 1997:654–656.

5. Hagler WS. Retinal dialysis: a statistical and genetic study todetermine prognostic factors. Trans Am Ophthalmol Soc1980;38:687.

6. Francois J. The role of heredity in retinal detachment. In:McPherson A, editor. New and controversial aspects of retinaldetachment. New York: Harper & Row Publishers Inc, 1968:123–191.

Multiple Cranial ArteriovenousMalformations in a Child WithEventual Blindness in theAffected EyeToru Yasuhara, MD, Tsunehiko Ikeda, PhD,Kan Koizumi, MD, Hiroshi Sawa, MD, andShigeru Kinoshita, MD, PhD

PURPOSE: To report a case of multiple cranial arterio-venous malformations involving the orbit and retina.METHOD: Case report. We treated a 7-year-old girl whowas diagnosed with a left submaxillary, a left retinal, aleft orbital, and a middle subdural arteriovenous malfor-mation.RESULTS: Enlargement of the arteriovenous malforma-tions, except for the retinal arteriovenous malformation,was observed. After external carotid artery embolizationsand radiation therapy for uncontrolled oral cavity bleed-ing, loss of light perception in the affected eye occurred,but no marked changes occurred in the retinal arterio-venous malformation.CONCLUSION: This rare case suggests that the clinicalfinding of a stable retinal arteriovenous malformationmay be associated with enlargement of arteriovenousmalformation lesions at other sites. (Am J Ophthalmol1999;127:99–101. © 1999 by Elsevier Science Inc. Allrights reserved.)

CRANIAL ARTERIOVENOUS MALFORMATIONS DEVELOP

most often unilaterally in one of the cerebral hemi-spheres and frequently present in patients between ages 10and 30 years. In addition to development in the cerebrum,one or more arteriovenous malformations may also developin the retina, orbit, or jaw; however, the occurrence of asubmaxillary arteriovenous malformation is rare.1–3 Wereport a 7-year-old girl who was diagnosed with a leftsubmaxillary, a left retinal, a left orbital, and a middlesubdural arteriovenous malformation and who eventuallydeveloped blindness in the left eye.

Accepted for publication July 8, 1998.From the Department of Ophthalmology, Kyoto Prefectural University

of Medicine, Kyoto, Japan.Inquiries to Toru Yasuhara, Department of Ophthalmology, Kyoto

Prefectural University of Medicine, 465 Hirokoji Kawaramachi, Kami-gyo-ku, Kyoto 602, Japan; fax: 81-75-251-5663.

FIGURE 1. The large retinal arteriovenous vascular malforma-tion in the left eye.

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