RETINAL LASER INJURY DURING A LASER SHOW Marina Shneck, MD, Jaime Levy, MD, Itamar Klemperer, MD, Tova Lifshitz, MD
Background: Laser injuries caused by Q-switched lasers are not unusual in the military and laboratories. To our knowledge, only one case of eye injury during a laser show has been reported previously. Methods: Case series. Results: All three patients had uniocular foveal hemorrhagic injury demonstrated by fluorescein angiography and optical coherence tomography. The lesions resolved within 6 months. Conclusions: Laser retinal injuries can cause transient or permanent visual damage. Accidental eye injuries during a laser show may be possible. RETINAL CASES & BRIEF REPORTS 1:178 –181, 2007
From the Department of Ophthalmology, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
defects. Laser injury to the fovea was diagnosed, and the patient was treated with oral prednisone starting at 1 mg/kg for 2 weeks, with rapid dose tapering. Optical coherence tomography (OCT) was performed 1 week after the injury and demonstrated foveal thickening, intraretinal blood, and shadowing effect on the retinal pigment epithelium (RPE) and choroid behind the hemorrhage (Fig. 1, bottom). Gradually, there was absorption of foveal hemorrhage until a normal macular appearance over a period of 10 weeks. Restoration of normal foveal architecture was demonstrated by OCT. Six months after the eye exposure to the laser, visual acuity was 20/20 in both eyes, and there were no scotomas. FA findings appeared normal.
T
hree adolescent males were referred to our department because of sudden recent visual loss in one eye. All of them were at the same party in a discotheque where a laser show was used. The patients had not met each other before and lived in different towns. Different ophthalmologists examined the patients during the first 2 days after the show. All three patients described unintentional viewing of the bright laser ray for several seconds when standing on the dance floor 2 m to 3 m from the laser. Shortly after, they had monocular visual decline.
Case 2 A 16-year-old boy sought examination because of visual decline in the right eye several hours after a party in the same discotheque as Patient 1 had attended. Vision was 20/200 in the right eye and 20/20 in the left eye. Results of anterior segment examination were unremarkable. Posterior segment examination revealed a deep foveal hemorrhage in the right eye (Fig. 2, top). The left eye was completely normal. FA and OCT findings were similar to those of Case 1 (Fig. 2, bottom). The patient was treated with oral prednisone (1 mg/kg) for 2 weeks, with rapid dose tapering. Partial absorption of the macular hemorrhage with transient appearance of retinal edema at the lesion borders and RPE disturbances were observed at the 1-week follow-up. Gradual absorption of the foveal hemorrhage was found by fundus examination. At the end of the 6-month follow-up, visual acuity returned to 20/30 in the right eye with no pathologic findings of fundus examination, FA, and OCT.
Case Reports Case 1 A 15-year-old boy sought examination because of an acute decrease in visual acuity in the left eye. Visual acuity was of 20/20 in the right eye and 20/100 in the left eye. Vision in the left eye decreased immediately after the disco party, but he presented for examination 36 hours later. The patient had left paracentral scotoma by Amsler chart testing. Results of anterior segment examination were normal. The right eye fundus was normal. There was foveal hemorrhage in the left eye (Fig. 1, top). Fluorescein angiography (FA) revealed foveal masking by blood with no window
Case 3
The authors have no proprietary interest in any of the materials or techniques used in this study. Reprint requests: Marina Shneck, MD, Department of Ophthalmology, Soroka University Medical Center, P.O. Box 151, BeerSheva 84101, Israel; e-mail: [email protected]
A 16-year-old adolescent male was examined 2 days after the monocular visual loss. He had loss of vision immediately after unintentional viewing of a bright green laser ray for a few seconds during the same party that Patients 1 and 2 had attended. Visual
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RETINAL LASER INJURY DURING A LASER SHOW
Fig. 1. Case 1. A, Color fundus photograph at presentation showing left foveal hemorrhage. B, Optical coherence tomography 1 week after the accident showing foveal thickening, intraretinal blood, and shadowing effect.
acuity was 20/20 in the right eye and 20/100 in the left eye. Amsler grid examination showed paracentral scotoma. Anterior segments were normal. The patient had foveal hemorrhage in the left eye (Fig. 3, top). There were no abnormal findings in his right eye. FA showed foveal masking by blood. OCT revealed foveal thickening, intraretinal blood and fluid, shadowing effect, and some choroidal/ RPE changes (Fig. 3, bottom). The patient was treated with oral prednisone (1 mg/kg), but he discontinued this treatment after 1 week because of abdominal pain. Partial absorption of macular hemorrhage with transient appearance of retinal edema at the lesion borders and RPE disturbances were observed 1 week after the injury. Visual acuity improved slowly during the follow-up period to 20/20, and the scotoma disappeared. Residual macular hemorrhage was still evident after 10 weeks of follow-up. Restoration of normal foveal architecture was observed at the end of the follow-up period by fundus examination and OCT. FA demonstrated resolution of the foveal hemorrhages with no window defects at the 6-month follow-up.
Discussion Most reported laser injuries are accidental exposure to laser in the military and laboratories. The estimated frequency of industrial and military laser injuries worldwide is ⬍15 cases.1 These injuries have been
179
Fig. 2. Case 2. A, Color fundus photograph at presentation showing deep foveal hemorrhage. B, Optical coherence tomography 1 week after the accident showing retinal thickening around the deep foveal hemorrhage and choroid shadowing effect by blood.
due to lasers in the visible and near-infrared spectrum, operated in pulse or continuous-wave mode. Many cases of laser pointer injuries have been reported,2,3 but most serious ocular laser accidents are caused by Q-switched lasers.1,3 We found only one case report concerning eye injuries during laser shows that described a juxtafoveal line–shaped defect conformed by FA as a vision defect and scotoma.4 Reported laser-induced retinal injuries are variable and most often involve the foveal or juxtafoveal areas: hypopigmented ring-shaped lesions, window defects with RPE disturbances, retinal scar, intra- and subretinal hemorrhages, vitreous and preretinal hemorrhages (mainly by pulsed-dye laser), and macular hole.3 Laser classification is based on the potential of a beam to cause biologic damage from unintentional viewing.2 The US Food and Drug Administration’s Center for Devices and Radiologic Health regulates the manufacture of commercial laser products. Manufacturers are required to classify laser products as Class 1, 2, 3A, 3B, or 4; certify by means of product
180
RETINAL CASES & BRIEF REPORTSℜ
Fig. 3. Case 3. A, Color fundus photograph with left eye foveal hemorrhage at presentation. B, Optical coherence tomography showing retinal thickening, juxtafoveal hemorrhage and fluid, shadowing effect, and some retinal pigment epithelium and choroid disturbances 1 week after the injury.
labels; and submit a report demonstrating that requirements of compliance standards are met. Class 4 laser devices are dangerous industrial, military, or medical lasers that produce ⬎500 mW of power. Commercially available lasers used for laser light shows and displays are generally of 800-mW to 3-W power and have scanner blanking or other scan systems for complex beam projections and graphics.5 The International Electrotechnical Commission and Center for Devices and Radiologic Health6 have specific practices and requirements for safe use of lasers in the entertainment industry. Our patients participated in a laser show where a Class 4 argon laser of 3-W power and two spectral lines (green, 510.6 nm; yellow, 578.2 nm) were used. Expert examination revealed that the instruction manual requirement to limit the laser exposure area to at least 2.5 m above the floor was not fulfilled. The legal aspects of the described laser show are still being investigated by the authorities.
●
2007
●
VOLUME 1
●
NUMBER 3
There are three damage mechanisms by laser beam: thermal, photochemical, and mechanical. Energy and pulse duration or exposure time determine the damage mechanism. Thermal damage is a consequence of the absorption of laser energy by the highly absorbing melanin contained within melanosomes in the RPE cells. Mechanical damage is caused by rapid extremely high energy absorption with a pulse duration of pico- to nanoseconds, like that of the Nd:YAG photodisruptor. Photochemical damage processes occur at low power and long pulses when slow delivery of energy induces changes or breaks in structural proteins and nucleic acids of photoreceptors. Our three patients had thermomechanical hemorrhagic retinal injuries. As in any neural injury, the retinal laser injury can expand due to release of various noxious substances and secondary degeneration. Systemic corticosteroid treatment was shown to have some neuroprotective effect for a short time after laser exposure, but this treatment interferes with regeneration of the neural tissue.3,7 The efficacy of corticosteroids in thermal laser injuries has not been proven. Our patients developed transient retinal edema 1 week after the laser exposure and still received steroid treatment for a short time. Except for one patient (Case 2), visual acuity returned to normal levels. The clinical course of macular laser injuries is characterized by sudden vision loss followed by gradual improvement and occasional late complications. Complications of retinal laser injuries could be severe: chorioretinal scarring, macular hole or cyst, macular pucker, choroidal neovascularization, permanent scotoma, and reduced contrast sensitivity. However, there is no proven medical or surgical treatment for most laser-induced retinal injuries. In conclusion, laser show injuries can cause transient or permanent visual damage. Laser retinal damage should be suspected in any patient with visual complaints after a potential laser exposure. All our patients had uniocular visual impairment due to foveal hemorrhages. All patients had gradual improvement. FA was not sensitive in determining laser-induced hemorrhagic lesions. OCT demonstrated intraretinal hemorrhages and RPE disturbances. Lasers used in laser light shows require control by authorized institutions. Accidental eye injuries during laser shows may be possible. Key words: foveal hemorrhage, fluorescein angiography, laser macular injury, laser show, optical coherence tomography.
181
RETINAL LASER INJURY DURING A LASER SHOW
Acknowledgment
3.
The authors thank the photographer, Ami Dahan, Soroka University Medical Center, Beer-Sheva, Israel, for his contribution.
4. 5. 6.
References 1.
2.
Mainster MA, Stuck BE, Brown J JR, et al. Assessment of alleged retinal laser injuries. Arch Ophthalmol 2004;122: 1210–1217. Mainster MA, Timberlake GT, Warren KA, Sliney DH. Pointers on laser pointers. Ophthalmology 1997;104:1213–1214.
7.
Barkana Y, Belkin M. Laser eye injuries. Surv Ophthalmol 2000;44:459–478. Sachs HG, Baumgathuber N, Lohmann CP. Eye injuries during a laser show. Klin Monatsbl Augenheilkd 1998;212:163–165. Laser Show Resource Guide, http://www.pangolin.com US FDA Center for Devices and Radiological Health. Laser Light Show Safety: Who’s Responsible. HHS Publication 868262. Washington, DC: US FDA. Hirschberg DL, Yoles E, Belkin M, Schwartz M. Inflammation after axonal injury has conflicting consequences for recovery of function: rescue of spared axons is impaired but regeneration is supported. J Neuroimmunol 1994;50:9–16.
Background: Laser injuries caused by Q-switched lasers are not unusual in the military and laboratories. To our knowledge, only one case of eye injury during a laser show has been reported previously. Methods: Case series. Results: All three patients had uniocular foveal hemorrhagic injury demonstrated by fluorescein angiography and optical coherence tomography. The lesions resolved within 6 months. Conclusions: Laser retinal injuries can cause transient or permanent visual damage. Accidental eye injuries during a laser show may be possible. RETINAL CASES & BRIEF REPORTS 1:178 –181, 2007
From the Department of Ophthalmology, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
defects. Laser injury to the fovea was diagnosed, and the patient was treated with oral prednisone starting at 1 mg/kg for 2 weeks, with rapid dose tapering. Optical coherence tomography (OCT) was performed 1 week after the injury and demonstrated foveal thickening, intraretinal blood, and shadowing effect on the retinal pigment epithelium (RPE) and choroid behind the hemorrhage (Fig. 1, bottom). Gradually, there was absorption of foveal hemorrhage until a normal macular appearance over a period of 10 weeks. Restoration of normal foveal architecture was demonstrated by OCT. Six months after the eye exposure to the laser, visual acuity was 20/20 in both eyes, and there were no scotomas. FA findings appeared normal.
T
hree adolescent males were referred to our department because of sudden recent visual loss in one eye. All of them were at the same party in a discotheque where a laser show was used. The patients had not met each other before and lived in different towns. Different ophthalmologists examined the patients during the first 2 days after the show. All three patients described unintentional viewing of the bright laser ray for several seconds when standing on the dance floor 2 m to 3 m from the laser. Shortly after, they had monocular visual decline.
Case 2 A 16-year-old boy sought examination because of visual decline in the right eye several hours after a party in the same discotheque as Patient 1 had attended. Vision was 20/200 in the right eye and 20/20 in the left eye. Results of anterior segment examination were unremarkable. Posterior segment examination revealed a deep foveal hemorrhage in the right eye (Fig. 2, top). The left eye was completely normal. FA and OCT findings were similar to those of Case 1 (Fig. 2, bottom). The patient was treated with oral prednisone (1 mg/kg) for 2 weeks, with rapid dose tapering. Partial absorption of the macular hemorrhage with transient appearance of retinal edema at the lesion borders and RPE disturbances were observed at the 1-week follow-up. Gradual absorption of the foveal hemorrhage was found by fundus examination. At the end of the 6-month follow-up, visual acuity returned to 20/30 in the right eye with no pathologic findings of fundus examination, FA, and OCT.
Case Reports Case 1 A 15-year-old boy sought examination because of an acute decrease in visual acuity in the left eye. Visual acuity was of 20/20 in the right eye and 20/100 in the left eye. Vision in the left eye decreased immediately after the disco party, but he presented for examination 36 hours later. The patient had left paracentral scotoma by Amsler chart testing. Results of anterior segment examination were normal. The right eye fundus was normal. There was foveal hemorrhage in the left eye (Fig. 1, top). Fluorescein angiography (FA) revealed foveal masking by blood with no window
Case 3
The authors have no proprietary interest in any of the materials or techniques used in this study. Reprint requests: Marina Shneck, MD, Department of Ophthalmology, Soroka University Medical Center, P.O. Box 151, BeerSheva 84101, Israel; e-mail: [email protected]
A 16-year-old adolescent male was examined 2 days after the monocular visual loss. He had loss of vision immediately after unintentional viewing of a bright green laser ray for a few seconds during the same party that Patients 1 and 2 had attended. Visual
178
RETINAL LASER INJURY DURING A LASER SHOW
Fig. 1. Case 1. A, Color fundus photograph at presentation showing left foveal hemorrhage. B, Optical coherence tomography 1 week after the accident showing foveal thickening, intraretinal blood, and shadowing effect.
acuity was 20/20 in the right eye and 20/100 in the left eye. Amsler grid examination showed paracentral scotoma. Anterior segments were normal. The patient had foveal hemorrhage in the left eye (Fig. 3, top). There were no abnormal findings in his right eye. FA showed foveal masking by blood. OCT revealed foveal thickening, intraretinal blood and fluid, shadowing effect, and some choroidal/ RPE changes (Fig. 3, bottom). The patient was treated with oral prednisone (1 mg/kg), but he discontinued this treatment after 1 week because of abdominal pain. Partial absorption of macular hemorrhage with transient appearance of retinal edema at the lesion borders and RPE disturbances were observed 1 week after the injury. Visual acuity improved slowly during the follow-up period to 20/20, and the scotoma disappeared. Residual macular hemorrhage was still evident after 10 weeks of follow-up. Restoration of normal foveal architecture was observed at the end of the follow-up period by fundus examination and OCT. FA demonstrated resolution of the foveal hemorrhages with no window defects at the 6-month follow-up.
Discussion Most reported laser injuries are accidental exposure to laser in the military and laboratories. The estimated frequency of industrial and military laser injuries worldwide is ⬍15 cases.1 These injuries have been
179
Fig. 2. Case 2. A, Color fundus photograph at presentation showing deep foveal hemorrhage. B, Optical coherence tomography 1 week after the accident showing retinal thickening around the deep foveal hemorrhage and choroid shadowing effect by blood.
due to lasers in the visible and near-infrared spectrum, operated in pulse or continuous-wave mode. Many cases of laser pointer injuries have been reported,2,3 but most serious ocular laser accidents are caused by Q-switched lasers.1,3 We found only one case report concerning eye injuries during laser shows that described a juxtafoveal line–shaped defect conformed by FA as a vision defect and scotoma.4 Reported laser-induced retinal injuries are variable and most often involve the foveal or juxtafoveal areas: hypopigmented ring-shaped lesions, window defects with RPE disturbances, retinal scar, intra- and subretinal hemorrhages, vitreous and preretinal hemorrhages (mainly by pulsed-dye laser), and macular hole.3 Laser classification is based on the potential of a beam to cause biologic damage from unintentional viewing.2 The US Food and Drug Administration’s Center for Devices and Radiologic Health regulates the manufacture of commercial laser products. Manufacturers are required to classify laser products as Class 1, 2, 3A, 3B, or 4; certify by means of product
180
RETINAL CASES & BRIEF REPORTSℜ
Fig. 3. Case 3. A, Color fundus photograph with left eye foveal hemorrhage at presentation. B, Optical coherence tomography showing retinal thickening, juxtafoveal hemorrhage and fluid, shadowing effect, and some retinal pigment epithelium and choroid disturbances 1 week after the injury.
labels; and submit a report demonstrating that requirements of compliance standards are met. Class 4 laser devices are dangerous industrial, military, or medical lasers that produce ⬎500 mW of power. Commercially available lasers used for laser light shows and displays are generally of 800-mW to 3-W power and have scanner blanking or other scan systems for complex beam projections and graphics.5 The International Electrotechnical Commission and Center for Devices and Radiologic Health6 have specific practices and requirements for safe use of lasers in the entertainment industry. Our patients participated in a laser show where a Class 4 argon laser of 3-W power and two spectral lines (green, 510.6 nm; yellow, 578.2 nm) were used. Expert examination revealed that the instruction manual requirement to limit the laser exposure area to at least 2.5 m above the floor was not fulfilled. The legal aspects of the described laser show are still being investigated by the authorities.
●
2007
●
VOLUME 1
●
NUMBER 3
There are three damage mechanisms by laser beam: thermal, photochemical, and mechanical. Energy and pulse duration or exposure time determine the damage mechanism. Thermal damage is a consequence of the absorption of laser energy by the highly absorbing melanin contained within melanosomes in the RPE cells. Mechanical damage is caused by rapid extremely high energy absorption with a pulse duration of pico- to nanoseconds, like that of the Nd:YAG photodisruptor. Photochemical damage processes occur at low power and long pulses when slow delivery of energy induces changes or breaks in structural proteins and nucleic acids of photoreceptors. Our three patients had thermomechanical hemorrhagic retinal injuries. As in any neural injury, the retinal laser injury can expand due to release of various noxious substances and secondary degeneration. Systemic corticosteroid treatment was shown to have some neuroprotective effect for a short time after laser exposure, but this treatment interferes with regeneration of the neural tissue.3,7 The efficacy of corticosteroids in thermal laser injuries has not been proven. Our patients developed transient retinal edema 1 week after the laser exposure and still received steroid treatment for a short time. Except for one patient (Case 2), visual acuity returned to normal levels. The clinical course of macular laser injuries is characterized by sudden vision loss followed by gradual improvement and occasional late complications. Complications of retinal laser injuries could be severe: chorioretinal scarring, macular hole or cyst, macular pucker, choroidal neovascularization, permanent scotoma, and reduced contrast sensitivity. However, there is no proven medical or surgical treatment for most laser-induced retinal injuries. In conclusion, laser show injuries can cause transient or permanent visual damage. Laser retinal damage should be suspected in any patient with visual complaints after a potential laser exposure. All our patients had uniocular visual impairment due to foveal hemorrhages. All patients had gradual improvement. FA was not sensitive in determining laser-induced hemorrhagic lesions. OCT demonstrated intraretinal hemorrhages and RPE disturbances. Lasers used in laser light shows require control by authorized institutions. Accidental eye injuries during laser shows may be possible. Key words: foveal hemorrhage, fluorescein angiography, laser macular injury, laser show, optical coherence tomography.
181
RETINAL LASER INJURY DURING A LASER SHOW
Acknowledgment
3.
The authors thank the photographer, Ami Dahan, Soroka University Medical Center, Beer-Sheva, Israel, for his contribution.
4. 5. 6.
References 1.
2.
Mainster MA, Stuck BE, Brown J JR, et al. Assessment of alleged retinal laser injuries. Arch Ophthalmol 2004;122: 1210–1217. Mainster MA, Timberlake GT, Warren KA, Sliney DH. Pointers on laser pointers. Ophthalmology 1997;104:1213–1214.
7.
Barkana Y, Belkin M. Laser eye injuries. Surv Ophthalmol 2000;44:459–478. Sachs HG, Baumgathuber N, Lohmann CP. Eye injuries during a laser show. Klin Monatsbl Augenheilkd 1998;212:163–165. Laser Show Resource Guide, http://www.pangolin.com US FDA Center for Devices and Radiological Health. Laser Light Show Safety: Who’s Responsible. HHS Publication 868262. Washington, DC: US FDA. Hirschberg DL, Yoles E, Belkin M, Schwartz M. Inflammation after axonal injury has conflicting consequences for recovery of function: rescue of spared axons is impaired but regeneration is supported. J Neuroimmunol 1994;50:9–16.
