October 16, 1995
This message from the Food and Drug Administration (FDA) is to remind you about the potential retinal hazards from operating microscopes, to review steps that can be taken to minimize the risks of retinal photic injury from operating microscopes, and to make sure physicians are aware of medical device reporting.
Retinal photic injury from an operating microscope was first reported in 1983. (1) Since that time, incidents of retinal photic injuries from operating microscopes continue to be reported sporadically. (2-16) While the majority of injuries produce minimal symptoms, scotoma and permanent central vision loss have occurred in some patients. (11) As is true with all photochemical damage, clinical abnormalities are not evident immediately. Retinal edema or mild pigmentary changes are typically discernable within one to two days after exposure and varying degrees of pigmentary modeling become more apparent after one to three weeks. (18)
Incidence of Injuries
The incidence of serious injury is not known, as is illustrated by the following studies, but significant permanent vision loss appears to be infrequent. A recent prospective study at a training institution found retinal photic injury from an operating microscope in 28% of patients. (11) In this study a microscope was used with relatively intense light and exposure times of 20 to 120 minutes. This study also demonstrated a dose-response relationship; the risk of retinal damage increased with increasing retinal exposure to the light from operating microscopes.
Another prospective study, performed at a different institution with an operating microscope that provided about 28% lower corneal irradiance levels and shorter exposure times (21 to 76 minutes), reported no retinal photic injuries. (16) Preoperatively, patients had detailed ocular examinations and , when possible, fundus photography and oral fluorography. Fluorescein angiography was performed after cataract surgery to identify the most subtle retinal photic injuries that may have occurred. In two additional retrospective studies, the incidence of retinal photic injuries was 7% and 3%. (8, 17)
Despite all efforts taken to minimize the risks of retinal damage, retinal photic injuries from the light source used in operating microscopes during cataract surgery and other intraocular procedures may occur. Several factors appear to be important determinants of photic retinal injury. These include: angle of light incidence, light intensity, exposure time, and intensity of the blue light component.
Actions to Reduce the Risk of Retinal Photic Injury
The following actions may reduce the risk of retinal photic injury from operating microscopes during cataract surgery:
- Use only that light intensity needed to clearly visualize and perform the surgical procedures.
- Do not assume that the intensity of the light from all operating microscopes is the same. Some are brighter than others. When using a new microscope, visually evaluate and set light levels to the lowest levels successfully used in the past.
- Replace lamps only with manufacturer-approved products.
- Because blue light has been shown to be more toxic than longer-wavelength light, the addition of a filter to exclude light below about 515 nm has been recommended, to eliminate blue light, especially in cases requiring prolonged light exposure. (18) However, a 515 nm short wavelength cut-off filter will result in a yellow light. Cut-off filters at wavelengths shorter than 515 nm to about the range of 420 - 435 nm will affect the color rendition of the light less and may still provide useful reduction in the risk of injury.
- Use oblique lighting if it is available, or otherwise shield the pupil when the red reflex is not required or the operating field permits. Oblique lighting may be used during phases of an operation that do not require coaxial light.
- Minimize direct exposure to the fovea.
- Educate residents about the above actions in order to help reduce the risks of retinal photic injury during training programs and in the future.
The American National Standards Institute (ANSI) is developing a proposed product performance standard that will be applicable to the manufacturers of operating microscopes used in ophthalmic surgery. This proposed standard will incorporate engineering, labeling, and user information requirements that are intended to make the device safer to use and the user aware of ways to minimize the risks associated with the use of the operating microscope during ocular surgery.
Reporting Requirements for Retinal Photic Injury Incidents
Although retinal photic injury from operating microscopes during cataract surgery is not a new phenomenon, some physicians may not be aware of the reporting requirements of the Safe Medical Devices Act of 1990 (SMDA). Prompt and accurate reporting by practitioners will help make it possible to obtain a better estimate of the incidence of retinal photic injury from operating microscopes during cataract surgery and other intraocular procedures.
The SMDA requires hospitals and other user facilities to report deaths, serious illnesses and injuries associated with the use of medical devices. The procedures established by your facility for such mandatory reporting should be followed. Practitioners who become aware of any medical device related adverse event or product problem/malfunction should report to their Medical Device User Facility Reporting person.
Even if an incident is not required to be reported under the SMDA, it would be helpful to report directly to MedWatch, the FDA's voluntary reporting program. Submit these reports to MedWatch: by phone at (800)FDA-1088, by FAX at (800)FDA-1078, or mail to: MedWatch
Food and Drug Administration
5600 Fishers Lane
Rockville, Maryland 20857.
For more information:
FDA Medical Device Public Health Notifications are available on the Internet. You can also be notified through email each time a new Public Health Notification is added to our web page. To subscribe, visit: http://service.govdelivery.com/service/subscribe.html?code=USFDA_39.
D. Bruce Burlington, M.D.
Center for Devices and Radiological Health
Food and Drug Administration
- Berler, D.K., and Peyser, R.: Light intensity and visual acuity following cataract surgery. Ophthalmology, 90:933, 1983.
- McDonald, H.R., and Irvine, A.R.: Light induced maculopathy from the operating microscope in extracapsular cataract extraction and intraocular lens implantation. Ophthalmology, 90:945, 1983.
- Boldrey, E.E., Ho, B.T., and Griffith, R.D.: Retinal burns occurring at cataract extraction. Ophthalmology, 91:1297, 1984.
- Delaey, J.J., de Wachter, A., Van Oye, R., and Verbraeken, H.: Retinal phototrauma during intraocular lens-implantation. Int. Ophthalmol., 7:109, 1984.
- Hupp, S.L.: Delayed, incomplete recovery of macular function after photic retinal damage associated with extracapsular cataract extraction and posterior lens insertion (correspondence). Arch. Ophthalmol., 105:1022, 1987.
- Johnson, R.N., Schatz, H., and McDonald, H.R.: Photic maculopathy. Arch. Ophthalmol., 105:1633, 1987.
- Khwarg, S.G., Geoghegan, M., and Hanscom, T.A.: Light-induced maculopathy from the operating microscope. Am. J. Ophthalmol., 98:628, 1984.
- Khwarg, S.G., Linstone, F.A., Daniels, S.A., Isenberg, S.J., Hanscom, T.A., Geoghegan, M., and Straatsma, B.R.: Incidence, risk factors and morphology in operating microscope light retinopathy. Am. J. Ophthalmol., 103:255, 1987.
- Lindquist, T.D., Grutzmacher, R.D., and Gofman, J.D.: Light-induced maculopathy. Potential for recovery. Arch. Ophthalmol., 104:1641, 1986.
- Ross, W.H.: Light-induced maculopathy. Am. J. Ophthalmol., 98:488, 1984.
- Byrnes, G.A., Antosyzk, A.N., Mazur, D.O., Kao, T.C., and Miller, S.A.: Photic Maculopathy after extracapsular cataract surgery. A prospective study. Ophthalmology, 99:731, 1992.
- Brod, R.D., Barron, B.A., Suelflow, J.A., Franklin, R. M., and Packer, A.J.: Phototoxic retinal damage during refractive surgery. Am. J. Ophthalmol., 102:121, 1986.
- Cech, J.M., Choromokos, E.A., and Sanitato, J.A.: Light-induced maculopathy following penetrating keratoplasty and lens implantation (correspondence). Arch. Ophthalmol., 105:751, 1987.
- Stamler, J.F., Blodi, C.F., Verdier, D., and Krachmer, J.H.: Microscope light-induced maculopathy in combined penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation. Ophthalmology, 95:1142, 1988.
- McDonald, H.R., and Harris, M.J.: Operating microscope-induced retinal phototoxicity during pars plana vitrectomy. Arch. Ophthalmol., 106:521, 1988.
- Byrnes, G.A., Chang, B.,, Loose, I., Miller, S.A., Benson, W.E.: Prospective incidence of photic maculopathy after cataract surgery. Am. J. Ophthalmol., 119:92, 1995.
- Gomolin, J.E., and Koenekoop, R.K.: Presumed photic retinopathy after cataract surgery: an angiographic study. Canadian J. of Ophthalmol., 221:4, 1993.
- Davidson, P. and Sternberg, P., Jr.: Potential Retinal Phototoxicity. American J. of Ophthalmology, 116:4, 1993.