Retinal Pigment Epithelial Tears Associated With Trauma Leonard A. Levin, M.D., Johanna M. Seddon, M.D., and Trexler Topping, M.D.
lWo previously healthy patients, a 66-yearold man with blunt trauma to the right eye, and a 28-year-old man with head trauma from a motorcycle accident, were observed to have parafoveal retinal pigment epithelial tears after injury. In both patients, fluorescein angiography demonstrated mottled window defects in the areas of the tears, and blocked fluorescence in the areas of the rolled-up pigment epithelium. Neither eye had evidence of pigment epithelial detachments. We hypothesize that this unusual phenomenon is caused by an acute tractional force oriented tangentially to the macular plane, the result of a rapid spherically expansile deformation of the globe during trauma.
T EARS of the retinal pigment epithelium were first reported in 1981 by Hoskin, Bird, and Sehmi,' as a complication of serous detachments of the pigment epithelium in patients with age-related maculopathy. Traction by the raised pigment epithelium at the margin of the detachment may be an important factor in their pathogenesis.! Retinal pigment epithelial tears have also been reported in certain other clinical settings, including in patients with a chorioretinal scar," retinal detachments," and after either glaucoma surgery' or laser photocoagulation of pigment epithelial detachments-! and subretinal neovascular membranes." We treated two patients with retinal pigment epithelial tears that developed after blunt trauma to the eye.
Accepted for publication July 9, 1991. From the Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School (Drs. Levin, Seddon, and Topping), Boston, Massachusetts; and Ophthalmic Consultants of Boston (Dr. Topping), Boston, Massachusetts. This study was supported in part by the Center for Eye Research, Boston, Massachusetts. Reprint requests to Leonard A. Levin, M.D., Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114.
396
Case Reports
Case 1 A 66-year-old man was seen in the Emergency Ward one hour after having been kicked in the right eye. There was no loss of consciousness. Except for refractive error, he had no history of previous ocular disorders. On examination, corrected visual acuity was R.E.: 20/ 100 and L.E.: 20/30, with no improvement with pinhole. The patient had moderate periorbital edema and ecchymosis around the right eye. Examination of the anterior segment of the right eye showed traumatic iritis, with two iris sphincter tears. Mild nuclear sclerosis was present in both eyes. Applanation tension was 21 mm Hg in each eye. The vitreous was clear in both eyes. Ophthalmoscopy of the right eye disclosed an orange-yellow, crescent-shaped area at the level of the pigment epithelium in the fovea, approximately 1 disk diameter in size, with a smaller, concentrically located, pigmented membrane (Fig. 1). A small area of serous detachment of the neuroretina was observed superiorly. There were minimal retinal pigment epithelium changes in the left macula. The peripheral retina was normal in both eyes. Fluorescein angiography was performed three days later. There was mottled hyperfluorescence of a crescent-shaped area (Fig. 2), corresponding to the de pigmented area seen on ophthalmoscopy, which was consistent with a pigment epithelial window defect. There was a smaller area of blocked fluorescence at the inferior edge, projecting into the center of the crescent-shaped window defect, which corresponded to the rolled-up pigment epithelium. Late views demonstrated leakage from a small area at the superior border of the tear (Fig. 3), which outlined the serous retinal detachment on delayed views (Fig. 4). Fluoroangiographic evidence of a pigment epithelial detachment was not seen in either eye. The patient was seen again one month later. Visual acuity was 20/80 in the right eye. The area corresponding to the depigmented retinal
©AMIlRICAN JOURNAL OF OPHTHALMOLOGY
112:396-400,
OCTOBER,
1991
Vol. 112, No.4
Traumatic Retinal Pigment Epithelial Tears
397
Fig. 1 (Levin, Seddon, and Topping). Case 1. The right eye demonstrated a hypopigmented, crescentshaped area in the fovea, with a smaller, concentrically located, hyperpigmented membrane, consistent with a retinal pigment epithelial tear. A small serous neuroretinal detachment superiorly was evident on biomicroscopy.
Fig. 2 (Levin, Seddon, and Topping). Case 1. A mid-to-late arteriovenous frame from the fluorescein angiogram demonstrated mottled hyperfluorescence of the crescent-shaped area, consistent with a pigment epithelial window defect, and a smaller area of blocked fluorescence seen inferiorly (arrow), corresponding to the rolled-up pigment epithelium.
Fig. 3 (Levin, Seddon, and Topping). Case 1. A later frame from the fluorescein angiogram demonstrated beginning leakage from an area at the superior border of the tear.
Fig. 4 (Levin, Seddon, and Topping). Case 1. A delayed frame from the fluorescein angiogram demonstrated the extent of the serous retinal detachment superior to the pigment epithelial tear.
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AMERICAN JOURNAL OF OPHTHALMOLOGY
October, 1991
Case 2 A 28-year-old man sustained head trauma and probable chest trauma in a motorcycle accident, losing consciousness for several minutes. He noticed blurred vision in his right eye, and was advised to see an ophthalmologist. There was no history of previous ocular disorders. Upon examination two days later, his visual acuity was R.E.: 20/40, not improving with pinhole, and L.E.: 20/20. Visual fields were full to finger counting in both eyes. The external appearance and anterior segment were normal. The vitreous was clear. Ophthalmoscopy of the right eye (Fig. 5) disclosed a few cotton-wool spots near the optic disk and the papillomacular bundle, consistent with mild
Purtscher's retinopathy. Some temporal striae were seen. An orange-yellow, ovoid area approximately 1 disk diameter in size at the level of the pigment epithelium was seen just temporal to the fovea. It was bisected above its midline by a horizontal pigmented band, consistent with a strip of rolled-up pigment epithelium, suggestive of a retinal pigment epithelial tear, with baring of Bruch's membrane. The fovea and peripheral retina appeared normal. The fellow eye was unremarkable. A fluorescein examination performed the day of clinical examination disclosed a pigment epithelial window defect temporal to the fovea (Fig. 6), corresponding to the retinal pigment epithelial tear that had been seen clinically. There was a narrow horizontal band of blocked fluorescence, corresponding to the rolled-up pigment epithelium. The angiogram also demonstrated some blurring of deeper retinal detail in the areas corresponding to the cotton-wool spots. No leakage was observed in the late phases of the angiogram. When the patient was seen in follow-up two weeks later, he had symptoms consistent with a
Fig. 5 (Levin, Seddon, and Topping). Case 2. The fundus at initial examination. A hypopigmented ovoid area was seen temporal to the fovea, bisected above the midline by a horizontal hyperpigmented band, consistent with a strip of rolled-up pigment epithelium. A retinal pigment epithelium defect was seen temporal to the tear. Cotton-wool spots were in the nasal macula.
Fig. 6 (Levin, Seddon, and Topping). Case 2. A mid-to-late arteriovenous frame from the initial fluorescein angiogram demonstrated a pigment epithelial window defect temporal to the fovea, corresponding to the area of the retinal pigment epithelial tear. A narrow horizontal band of blocked fluorescence corresponded to the rolled-up pigment epithelium. Window defects were seen temporal to the tear.
pigment epithelial tear remained a mottled orange-yellow. The highly pigmented rolledup pigment epithelium at the inferior border of the tear had depigmented markedly. On fluorescein angiography, there was still a marked window defect in the area corresponding to the tear, and a persistent late leakage superiorly. The patient was lost to follow-up.
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Traumatic Retinal Pigment Epithelial Tears
right paracentral scotoma. Visual acuity had improved to 20/20 in both eyes. The cottonwool spots and retinal striae had resolved. The area of pigment epithelial defect temporal to the fovea persisted, but the rolled-up retinal pigment epithelium was smaller and more pigmented. When the patient was seen seven months after the original accident, the findings were the same.
Discussion Retinal pigment epithelial tears have usually been observed in the presence of pigment epithelial detachments in patients with age-related maculopathy. In these patients, there is tearing at the margin of the detachment, where the raised pigment epithelium meets the flat pigment epithelium. Hoskin, Bird, and Sehmi' first described this entity in 1981, presenting data from 44 eyes of 36 patients with retinal pigment epithelial tears. Of these, 12 eyes had been previously examined, and all were observed to have pigment epithelial detachments. Seven patients with retinal pigment epithelial tears that occurred after laser photocoagulation were also described. Because of heterogeneity of the fluorescence pattern seen in the detachments before tearing, these investigators theorized that there were two cleavage planes between pigment epithelium and Bruch's membrane: one between the pigment epithelial basement membrane and Bruch's membrane, and one between the pigment epithelial cells and their own basement membrane. Gass? presented evidence to suggest that the only cleavage plane is between the pigment epithelial basement membrane and Bruch's membrane, and that subpigment epithelium choroidal neovascularization was responsible for the detachment and tear. This was consistent with a report by Cantrill, Ramsay, and Knobloch" in which six patients with retinal pigment epithelial tears were described. Most of the patients had evidence of occult choroidal neovascularization, presumably as a late result of their agerelated maculopathy. These researchers, along with Green and Yarian," also believed that the cleavage plane is between the pigment epithelial basement membrane and the inner collagenous layer of Bruch's membrane, on the basis of the tight adherence of pigment epithelial cells to their basement membrane, as demonstrated by Goldbaum and Madden."
399
Although retinal pigment epithelial tears were initially described in association with pigment epithelial detachments, in the context of age-related maculopathy, and most reported cases have been consistent with this presumed cause, there have been several other associations. 3,4,7.l o Swanson, Kalina, and Guzak" described three cases of retinal pigment epithelial tears that occurred in clinical settings other than pigment epithelial detachments. In a 74year-old woman, a tear was observed encompassing an old chorioretinal scar, without a known precipitating event. A retinal pigment epithelial tear was seen in association with a rhegmatogenous retinal detachment in a 49year-old woman with proliferative vitreoretinopathy. A 48-year-old man had a large retinal pigment epithelial tear in the setting of an exudative retinal detachment. Retinal pigment epithelial tears after laser photocoagulation of choroidal neovascular membranes have been described.v" Presumably, tearing is caused by excessive traction from laser-induced shrinkage of the thickened membrane. Laatikainen and Syrdalerr' described two patients who had retinal pigment epithelial tears after trabeculectomy for open-angle glaucoma. In both patients, hypotony followed the surgery, in association with exudative retinal detachment in one patient, and choroidal detachment in the other. In each of our cases, there was evidence for significant forces being involved, as shown by the development of traumatic iritis with iris sphincter tears in Case I, and loss of consciousness and Purtscher's retinopathy (presumably from chest trauma) in Case 2. Although we did not have the opportunity to examine the patients before their trauma, the correlation of a visual defect directly attributable to the retinal pigment epithelial tear (decreased central vision in Case 1 and a paracentral scotoma in Case 2), and a directly observable acute pigment epithelium lesion, suggest that the tears were the result of the trauma. We cannot completely exclude the possibility that the patients had pre-existing pigment epithelial detachments, and that the trauma then precipitated the tearing of the pigment epithelium. However, neither patient had pre-existing metamorphopsia, scotomata, or other visual symptoms. A pigment epithelial detachment would be extremely unlikely in the second patient, a 28year-old with no other maculopathy. We therefore believe that the retinal pigment epithelial tears described in these two patients
400
October, 1991
AMERICAN JOURNAL OF OPHTHALMOLOGY
occurred primarily as the result of trauma to the eye. We considered the mechanisms that could underlie this particular response to blunt trauma, and why retinal pigment epithelial tears are so rarely seen in ocular trauma. We hypothesize that the forces responsible for tearing are a result of acute tangential stresses on and around the posterior pole, similar to those described by Delori, Pomerantzeff, and Cox" and Pruett, Weiter, and Goldstein." Trauma only rarely results in retinal pigment epithelial tears, probably because this force must fit into an extremely narrow window. If the force is too strong, both the pigment epithelium and Bruch's membrane will be torn, and the commonly seen choroidal rupture will result. Both choroidal ruptures and retinal pigment epithelial tears have a temporal preponderance.P-" If the force is too small, no tears will result. Only if the force is just enough to tear the pigment epithelium, but not Bruch's membrane, will a traumatic retinal pigment epithelial tear result. The tears in our patients were oriented in the horizontal plane, which is an uncommon configuration for choroidal ruptures, but not an impossible one, as shown by Pruett, Weiter, and Goldstein." The horizontal orientation may also reflect differential directional sensitivity to stretch of retinal pigment epithelium and Bruch's membrane. Further observation of similar cases may confirm or disprove this hypothesis. The more common retinal pigment epithelial tear after pigment epithelium detachment probably results from radial stress on the pigment epithelium when the relatively flexible pigment epithelium and neuroretina are stretched by serous exudate over the far stiffer Bruch's membrane and sclera. Pigment epithelium detachments may be predisposed to tearing, because the window of acceptable forces is significantly wider, and the stretched retinal pigment epithelium can tear with weaker forces. Tearing may occur when the strain exceeds the elastic limits of the tissue. Laser treatment may cause
tightening of the pigment epithelium over the detachment, increasing the stress, and thus the risk of a tear.
References 1. Hoskin, A., Bird, A. c., and Sehmi, K.: Tears of detached retinal pigment epithelium. Br. ]. Ophthalmol. 65:417, 1981. 2. Cantrill, H. L., Ramsay, R. C., and Knobloch, W. H.: Rips in the pigment epithelium. Arch. Ophthalmol. 101:1074, 1983. 3. Swanson, D. E., Kalina, R. E., and Cuzak, S. V.: Tears of the retinal pigment epithelium. Occurrence in retinal detachments and a chorioretinal scar. Retina 4:115, 1984. 4. Laatikainen, L., and Syrdalen, P.: Tearing of retinal pigment epithelium after glaucoma surgery. Graefes Arch. Clin. Exp. Ophthalmol. 225:308,1987. 5. Norose, K., Tanino, T., and Segawa, K.: Bilateral tears of the retinal pigment epithelium. Br. J. Ophthalmol. 72:621, 1988. 6. Gass, J. D.: Retinal pigment epithelial rip during krypton red laser photocoagulation. Am. J. Ophthalmol. 98:700, 1984. 7. - - : Pathogenesis of tears of the retinal pigment epithelium. Br. J. Ophthalmol. 68:513, 1984. 8. Green, S. N., and Yarian, D.: Acute tear of the retinal pigment epithelium. Retina 3:16, 1983. 9. Goldbaum, M. H., and Madden, K.: A new perspective on Bruch's membrane and the retinal pigment epithelium. Br. J. Ophthalmol. 66:17, 1982. 10. Yeo, J. H., Marcus,S., and Murphy, R. P.: Retinal pigment epithelial tears. Patterns and prognosis. Ophthalmology 95:8, 1988. 11. Delori, F., Pomerantzeff, 0., and Cox, M.S.: Deformation of the globe under high-speed impact. Its relation to contusion injuries. Invest. Ophthalmol. 8:290, 1969. 12. Pruett, R. c.. Weiter, J. J., and Goldstein, R. B.: Myopic cracks, angioid streaks, and traumatic tears in Bruch's membrane. Am. J. Ophthalmol. 103:537, 1987. 13. Decker, W. L., Sanborn, G. E., Ridley, M., Annesley, W. H., and Sorr, E. M.: Retinal pigment epithelial tears. Ophthalmology 90:507, 1983.
lWo previously healthy patients, a 66-yearold man with blunt trauma to the right eye, and a 28-year-old man with head trauma from a motorcycle accident, were observed to have parafoveal retinal pigment epithelial tears after injury. In both patients, fluorescein angiography demonstrated mottled window defects in the areas of the tears, and blocked fluorescence in the areas of the rolled-up pigment epithelium. Neither eye had evidence of pigment epithelial detachments. We hypothesize that this unusual phenomenon is caused by an acute tractional force oriented tangentially to the macular plane, the result of a rapid spherically expansile deformation of the globe during trauma.
T EARS of the retinal pigment epithelium were first reported in 1981 by Hoskin, Bird, and Sehmi,' as a complication of serous detachments of the pigment epithelium in patients with age-related maculopathy. Traction by the raised pigment epithelium at the margin of the detachment may be an important factor in their pathogenesis.! Retinal pigment epithelial tears have also been reported in certain other clinical settings, including in patients with a chorioretinal scar," retinal detachments," and after either glaucoma surgery' or laser photocoagulation of pigment epithelial detachments-! and subretinal neovascular membranes." We treated two patients with retinal pigment epithelial tears that developed after blunt trauma to the eye.
Accepted for publication July 9, 1991. From the Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School (Drs. Levin, Seddon, and Topping), Boston, Massachusetts; and Ophthalmic Consultants of Boston (Dr. Topping), Boston, Massachusetts. This study was supported in part by the Center for Eye Research, Boston, Massachusetts. Reprint requests to Leonard A. Levin, M.D., Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114.
396
Case Reports
Case 1 A 66-year-old man was seen in the Emergency Ward one hour after having been kicked in the right eye. There was no loss of consciousness. Except for refractive error, he had no history of previous ocular disorders. On examination, corrected visual acuity was R.E.: 20/ 100 and L.E.: 20/30, with no improvement with pinhole. The patient had moderate periorbital edema and ecchymosis around the right eye. Examination of the anterior segment of the right eye showed traumatic iritis, with two iris sphincter tears. Mild nuclear sclerosis was present in both eyes. Applanation tension was 21 mm Hg in each eye. The vitreous was clear in both eyes. Ophthalmoscopy of the right eye disclosed an orange-yellow, crescent-shaped area at the level of the pigment epithelium in the fovea, approximately 1 disk diameter in size, with a smaller, concentrically located, pigmented membrane (Fig. 1). A small area of serous detachment of the neuroretina was observed superiorly. There were minimal retinal pigment epithelium changes in the left macula. The peripheral retina was normal in both eyes. Fluorescein angiography was performed three days later. There was mottled hyperfluorescence of a crescent-shaped area (Fig. 2), corresponding to the de pigmented area seen on ophthalmoscopy, which was consistent with a pigment epithelial window defect. There was a smaller area of blocked fluorescence at the inferior edge, projecting into the center of the crescent-shaped window defect, which corresponded to the rolled-up pigment epithelium. Late views demonstrated leakage from a small area at the superior border of the tear (Fig. 3), which outlined the serous retinal detachment on delayed views (Fig. 4). Fluoroangiographic evidence of a pigment epithelial detachment was not seen in either eye. The patient was seen again one month later. Visual acuity was 20/80 in the right eye. The area corresponding to the depigmented retinal
©AMIlRICAN JOURNAL OF OPHTHALMOLOGY
112:396-400,
OCTOBER,
1991
Vol. 112, No.4
Traumatic Retinal Pigment Epithelial Tears
397
Fig. 1 (Levin, Seddon, and Topping). Case 1. The right eye demonstrated a hypopigmented, crescentshaped area in the fovea, with a smaller, concentrically located, hyperpigmented membrane, consistent with a retinal pigment epithelial tear. A small serous neuroretinal detachment superiorly was evident on biomicroscopy.
Fig. 2 (Levin, Seddon, and Topping). Case 1. A mid-to-late arteriovenous frame from the fluorescein angiogram demonstrated mottled hyperfluorescence of the crescent-shaped area, consistent with a pigment epithelial window defect, and a smaller area of blocked fluorescence seen inferiorly (arrow), corresponding to the rolled-up pigment epithelium.
Fig. 3 (Levin, Seddon, and Topping). Case 1. A later frame from the fluorescein angiogram demonstrated beginning leakage from an area at the superior border of the tear.
Fig. 4 (Levin, Seddon, and Topping). Case 1. A delayed frame from the fluorescein angiogram demonstrated the extent of the serous retinal detachment superior to the pigment epithelial tear.
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AMERICAN JOURNAL OF OPHTHALMOLOGY
October, 1991
Case 2 A 28-year-old man sustained head trauma and probable chest trauma in a motorcycle accident, losing consciousness for several minutes. He noticed blurred vision in his right eye, and was advised to see an ophthalmologist. There was no history of previous ocular disorders. Upon examination two days later, his visual acuity was R.E.: 20/40, not improving with pinhole, and L.E.: 20/20. Visual fields were full to finger counting in both eyes. The external appearance and anterior segment were normal. The vitreous was clear. Ophthalmoscopy of the right eye (Fig. 5) disclosed a few cotton-wool spots near the optic disk and the papillomacular bundle, consistent with mild
Purtscher's retinopathy. Some temporal striae were seen. An orange-yellow, ovoid area approximately 1 disk diameter in size at the level of the pigment epithelium was seen just temporal to the fovea. It was bisected above its midline by a horizontal pigmented band, consistent with a strip of rolled-up pigment epithelium, suggestive of a retinal pigment epithelial tear, with baring of Bruch's membrane. The fovea and peripheral retina appeared normal. The fellow eye was unremarkable. A fluorescein examination performed the day of clinical examination disclosed a pigment epithelial window defect temporal to the fovea (Fig. 6), corresponding to the retinal pigment epithelial tear that had been seen clinically. There was a narrow horizontal band of blocked fluorescence, corresponding to the rolled-up pigment epithelium. The angiogram also demonstrated some blurring of deeper retinal detail in the areas corresponding to the cotton-wool spots. No leakage was observed in the late phases of the angiogram. When the patient was seen in follow-up two weeks later, he had symptoms consistent with a
Fig. 5 (Levin, Seddon, and Topping). Case 2. The fundus at initial examination. A hypopigmented ovoid area was seen temporal to the fovea, bisected above the midline by a horizontal hyperpigmented band, consistent with a strip of rolled-up pigment epithelium. A retinal pigment epithelium defect was seen temporal to the tear. Cotton-wool spots were in the nasal macula.
Fig. 6 (Levin, Seddon, and Topping). Case 2. A mid-to-late arteriovenous frame from the initial fluorescein angiogram demonstrated a pigment epithelial window defect temporal to the fovea, corresponding to the area of the retinal pigment epithelial tear. A narrow horizontal band of blocked fluorescence corresponded to the rolled-up pigment epithelium. Window defects were seen temporal to the tear.
pigment epithelial tear remained a mottled orange-yellow. The highly pigmented rolledup pigment epithelium at the inferior border of the tear had depigmented markedly. On fluorescein angiography, there was still a marked window defect in the area corresponding to the tear, and a persistent late leakage superiorly. The patient was lost to follow-up.
Vol. 112, No.4
Traumatic Retinal Pigment Epithelial Tears
right paracentral scotoma. Visual acuity had improved to 20/20 in both eyes. The cottonwool spots and retinal striae had resolved. The area of pigment epithelial defect temporal to the fovea persisted, but the rolled-up retinal pigment epithelium was smaller and more pigmented. When the patient was seen seven months after the original accident, the findings were the same.
Discussion Retinal pigment epithelial tears have usually been observed in the presence of pigment epithelial detachments in patients with age-related maculopathy. In these patients, there is tearing at the margin of the detachment, where the raised pigment epithelium meets the flat pigment epithelium. Hoskin, Bird, and Sehmi' first described this entity in 1981, presenting data from 44 eyes of 36 patients with retinal pigment epithelial tears. Of these, 12 eyes had been previously examined, and all were observed to have pigment epithelial detachments. Seven patients with retinal pigment epithelial tears that occurred after laser photocoagulation were also described. Because of heterogeneity of the fluorescence pattern seen in the detachments before tearing, these investigators theorized that there were two cleavage planes between pigment epithelium and Bruch's membrane: one between the pigment epithelial basement membrane and Bruch's membrane, and one between the pigment epithelial cells and their own basement membrane. Gass? presented evidence to suggest that the only cleavage plane is between the pigment epithelial basement membrane and Bruch's membrane, and that subpigment epithelium choroidal neovascularization was responsible for the detachment and tear. This was consistent with a report by Cantrill, Ramsay, and Knobloch" in which six patients with retinal pigment epithelial tears were described. Most of the patients had evidence of occult choroidal neovascularization, presumably as a late result of their agerelated maculopathy. These researchers, along with Green and Yarian," also believed that the cleavage plane is between the pigment epithelial basement membrane and the inner collagenous layer of Bruch's membrane, on the basis of the tight adherence of pigment epithelial cells to their basement membrane, as demonstrated by Goldbaum and Madden."
399
Although retinal pigment epithelial tears were initially described in association with pigment epithelial detachments, in the context of age-related maculopathy, and most reported cases have been consistent with this presumed cause, there have been several other associations. 3,4,7.l o Swanson, Kalina, and Guzak" described three cases of retinal pigment epithelial tears that occurred in clinical settings other than pigment epithelial detachments. In a 74year-old woman, a tear was observed encompassing an old chorioretinal scar, without a known precipitating event. A retinal pigment epithelial tear was seen in association with a rhegmatogenous retinal detachment in a 49year-old woman with proliferative vitreoretinopathy. A 48-year-old man had a large retinal pigment epithelial tear in the setting of an exudative retinal detachment. Retinal pigment epithelial tears after laser photocoagulation of choroidal neovascular membranes have been described.v" Presumably, tearing is caused by excessive traction from laser-induced shrinkage of the thickened membrane. Laatikainen and Syrdalerr' described two patients who had retinal pigment epithelial tears after trabeculectomy for open-angle glaucoma. In both patients, hypotony followed the surgery, in association with exudative retinal detachment in one patient, and choroidal detachment in the other. In each of our cases, there was evidence for significant forces being involved, as shown by the development of traumatic iritis with iris sphincter tears in Case I, and loss of consciousness and Purtscher's retinopathy (presumably from chest trauma) in Case 2. Although we did not have the opportunity to examine the patients before their trauma, the correlation of a visual defect directly attributable to the retinal pigment epithelial tear (decreased central vision in Case 1 and a paracentral scotoma in Case 2), and a directly observable acute pigment epithelium lesion, suggest that the tears were the result of the trauma. We cannot completely exclude the possibility that the patients had pre-existing pigment epithelial detachments, and that the trauma then precipitated the tearing of the pigment epithelium. However, neither patient had pre-existing metamorphopsia, scotomata, or other visual symptoms. A pigment epithelial detachment would be extremely unlikely in the second patient, a 28year-old with no other maculopathy. We therefore believe that the retinal pigment epithelial tears described in these two patients
400
October, 1991
AMERICAN JOURNAL OF OPHTHALMOLOGY
occurred primarily as the result of trauma to the eye. We considered the mechanisms that could underlie this particular response to blunt trauma, and why retinal pigment epithelial tears are so rarely seen in ocular trauma. We hypothesize that the forces responsible for tearing are a result of acute tangential stresses on and around the posterior pole, similar to those described by Delori, Pomerantzeff, and Cox" and Pruett, Weiter, and Goldstein." Trauma only rarely results in retinal pigment epithelial tears, probably because this force must fit into an extremely narrow window. If the force is too strong, both the pigment epithelium and Bruch's membrane will be torn, and the commonly seen choroidal rupture will result. Both choroidal ruptures and retinal pigment epithelial tears have a temporal preponderance.P-" If the force is too small, no tears will result. Only if the force is just enough to tear the pigment epithelium, but not Bruch's membrane, will a traumatic retinal pigment epithelial tear result. The tears in our patients were oriented in the horizontal plane, which is an uncommon configuration for choroidal ruptures, but not an impossible one, as shown by Pruett, Weiter, and Goldstein." The horizontal orientation may also reflect differential directional sensitivity to stretch of retinal pigment epithelium and Bruch's membrane. Further observation of similar cases may confirm or disprove this hypothesis. The more common retinal pigment epithelial tear after pigment epithelium detachment probably results from radial stress on the pigment epithelium when the relatively flexible pigment epithelium and neuroretina are stretched by serous exudate over the far stiffer Bruch's membrane and sclera. Pigment epithelium detachments may be predisposed to tearing, because the window of acceptable forces is significantly wider, and the stretched retinal pigment epithelium can tear with weaker forces. Tearing may occur when the strain exceeds the elastic limits of the tissue. Laser treatment may cause
tightening of the pigment epithelium over the detachment, increasing the stress, and thus the risk of a tear.
References 1. Hoskin, A., Bird, A. c., and Sehmi, K.: Tears of detached retinal pigment epithelium. Br. ]. Ophthalmol. 65:417, 1981. 2. Cantrill, H. L., Ramsay, R. C., and Knobloch, W. H.: Rips in the pigment epithelium. Arch. Ophthalmol. 101:1074, 1983. 3. Swanson, D. E., Kalina, R. E., and Cuzak, S. V.: Tears of the retinal pigment epithelium. Occurrence in retinal detachments and a chorioretinal scar. Retina 4:115, 1984. 4. Laatikainen, L., and Syrdalen, P.: Tearing of retinal pigment epithelium after glaucoma surgery. Graefes Arch. Clin. Exp. Ophthalmol. 225:308,1987. 5. Norose, K., Tanino, T., and Segawa, K.: Bilateral tears of the retinal pigment epithelium. Br. J. Ophthalmol. 72:621, 1988. 6. Gass, J. D.: Retinal pigment epithelial rip during krypton red laser photocoagulation. Am. J. Ophthalmol. 98:700, 1984. 7. - - : Pathogenesis of tears of the retinal pigment epithelium. Br. J. Ophthalmol. 68:513, 1984. 8. Green, S. N., and Yarian, D.: Acute tear of the retinal pigment epithelium. Retina 3:16, 1983. 9. Goldbaum, M. H., and Madden, K.: A new perspective on Bruch's membrane and the retinal pigment epithelium. Br. J. Ophthalmol. 66:17, 1982. 10. Yeo, J. H., Marcus,S., and Murphy, R. P.: Retinal pigment epithelial tears. Patterns and prognosis. Ophthalmology 95:8, 1988. 11. Delori, F., Pomerantzeff, 0., and Cox, M.S.: Deformation of the globe under high-speed impact. Its relation to contusion injuries. Invest. Ophthalmol. 8:290, 1969. 12. Pruett, R. c.. Weiter, J. J., and Goldstein, R. B.: Myopic cracks, angioid streaks, and traumatic tears in Bruch's membrane. Am. J. Ophthalmol. 103:537, 1987. 13. Decker, W. L., Sanborn, G. E., Ridley, M., Annesley, W. H., and Sorr, E. M.: Retinal pigment epithelial tears. Ophthalmology 90:507, 1983.
