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Argon Laser Photocoagulation Treatment in Central Serous Chorioretinopathy
Argon Laser Photocoagulation Treatment in Central Serous Chorioretinopathy DENNIS M. ROBERTSON, MD
Abstract: Central serous chorioretinopathy, a sporadic self-limited disease of young adults, is associated with loss of central vision, image distortion, and impaired dark adaptation. The diagnosis is verified with fluorescein angiography, which demonstrates an expanding point of fluorescein dye leakage under a serous detachment of the sensory retina. Treatment should ordinarily be delayed four or more months but may be considered if there is evidence of microarchitectural changes in the macular retina, if the best corrected visual acuity declines to 20/40 or less, or if there have been multiple recurrences. Argon laser photocoagulation should be directed to the leakage site, using spot sizes of 200 f..L in diameter, exposure times of 0.2 seconds, and low-power intensities. [Key words: central serous chorioretinopathy, direct laser photocoagulation, indirect laser photocoagulation, laser photocoagulation.] Ophthalmology 93:972974, 1986
Central serous chorioretinopathy (CSR) is a sporadic disorder of unknown cause occurring in the eyes of young and middle-aged adults. It is characterized by the accumulation of serous fluid under the sensory retina, usually in the region of the macula. Patients often complain of blurred central vision image distortion (micropsia) and impaired dark adaptation. Spontaneous remission with near total visual recovery is the rule in CSR. Although the recovery time is unpredictable, vision usually recovers to normal or near normal within several months. Visual loss can be permanent if recovery time is prolonged or if recurrences are frequent. The diagnosis of CSR can be made clinically, but fluorescein angiography is necessary to rule out the presence of a subretinal neovascular membrane that may cause a serous detachment of the sensory retina that can mimic CSR. The fluorescein angiogram
From the Department of Ophthalmology, Mayo Clinic, Mayo Medical School, and Mayo Foundation, Rochester, Minnesota. Presented at an Annual Meeting of the American Academy of Ophthalmology. Supported in part by funds from Research to Prevent Blindness, Inc. and NEI grant EY01709. Reprint requests to Dennis M. Robertson, MD, Department of Ophthalmology, Mayo Clinic, Mayo Foundation, Mayo Medical School, Rochester, MN 55905.
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will identify in CSR a focal point of hyperfluorescence that usually expands symmetrically or, less commonly, asymmetrically so that the dye ascends and diffuses like smoke in the subretinal space. If the fluorescein angiogram shows a pattern suspicious for a subretinal neovascular membrane, the stereo angiography should be repeated in two to three weeks. If a subretinal neovascular membrane is present, it will likely become more obvious during the interval, making the diagnosis easier. The condition is not CSR if a hemorrhage is present, if a donut-shaped ring of pigmentation is visible at the level of the retinal pigment epithelium, or if there is a pit in the optic nerve. The diagnosis must be made with caution if the patient is 55 years of age or older or if there are multiple defects in the pigment epithelium. Even with a clinical and fluorescein angiographic appearance typical of CSR, I regard the condition in a patient 55 years of age or older as a subretinal neovascular membrane and treat the site of dye leakage with heavy photocoagulation as if it were a neovascular membrane. Spontaneous remission with near total visual recovery is the rule in CSR. Although the recovery time is unpredictable, vision usually recovers to normal or near normal within several months. Visual loss can be permanent if recovery time is prolonged or if recurrences are frequent. The first conclusive study to indicate that laser photocoagulation could be effective in the management of CSR was conducted by Watzke et al.I When the laser
ROBERTSON
•
CENTRAL SEROUS CHORIORETINOPATHY
treatment was directed to the site of fluorescein dye leakage, they found that the duration of the disease course could be shortened by an average of approximately two months. In spite of this shortened course, the final visual result did not appear to be significantly affected in their study. For most cases, laser photocoagulation directed to the leakage site is safe to use. However, if the site of fluorescein dye leakage is at or near the fovea, photocoagulation of this site will likely cause permanent visual loss. In such cases, Wessing suggested more than a decade ago that photocoagulation could be directed to any site under the serous detachment, in an area remote from the site of fluorescein dye leakage (so-called indirect photocoagulation), and that such indirect photocoagulation might be effective in promoting early absorption of the subretinal fluid. 2 Although there are some laboratory studies supporting the concept that such photocoagulation to the serious detachment away from the leak site might be effective, a randomized clinical study of CSR, conducted by Watzke et aI, indicated that indirect argon laser photocoagulation was inferior to direct argon laser photocoagulation. 3 In an effort to clarify the role oflaser photocoagulation in the management of CSR, we reported a prospective randomized clinical trial at the Mayo Clinic comparing treatment with direct, indirect, and sham argon laser photocoagulation in the management of CSR.4 This study repeated some of the work by Watzke et aI, comparing direct with indirect photocoagulation, but it also expanded their study by comparing indirect photocoagulation with a sham-treated control group. Our study also addressed the problem of recurrences.
MATERIALS AND METHODS In the Mayo Clinic study, eyes were stratified into two groups, depending on the site of fluorescein dye leakage. 4 Eyes in which the leakage site was found to be within the papillomacular bundle or within 500 /-L of the capillaryfree zone of the macula (an area for purposes of this study referred to as the critical zone) were stratified to group A. These eyes were then randomly assigned either a real indirect argon laser photocoagulation treatment or a sham treatment. Eyes in which the leakage site was outside the papillomacular bundle and more than 500 /-L from the capillary-free zone were stratified to group B. These eyes were randomly assigned either a direct or indirect argon laser photocoagulation. The indirect peripheral laser photocoagulation was directed to the pigment epithelium under the elevated retina at a site remote from both the sites of fluorescein dye leakage and the critical zone. Three burns 200 /-L in diameter with exposure times of 0.2 seconds and powers between 80 and 120 m W were used to produce minimally visible lesions at the level of the pigment epithelium. For eyes assigned to the sham photocoagulation group, a sham treatment was given through the contact lens with the aiming beam. Eyes assigned to the direct laser pho-
tocoagulation treatment group received burns similar in size and intensity to those delivered with the indirect photocoagulation technique. Having agreed to participate in the study and having signed a consent form, all patients were positioned at the laser, and a sealed envelope containing the randomized treatment assignment was opened. The disease was considered resolved when two examiners concluded on the same date that (1) subretinal fluid was absent on biomicroscopic examination, and (2) stereoscopic fluorescein angiograms showed no active leakage.
RESULTS A statistical analysis ofthe results of our study indicated that, of the 30 eyes in group A, there was no difference in weeks to resolution from the time the patient entered the study between the control group treated with sham laser photocoagulation and the group treated with indirect laser photocoagulation. 4 Of the 12 eyes in group B that were randomly assigned either direct photocoagulation or indirect photocoagulation, the results indicated that the direct laser photocoagulation shortened the duration of CSR by approximately two months, a difference that was not only statistically highly significant but that also compared almost identically to those figures reported by Watzke et al. l During a I lh-year follow-up, recurrences were observed in a total of 12 patients. In almost all instances, these recurrences occurred within 100 /-L of the original site of fluorescein dye leakage. Recurrences were recognized in 8 of the 20 eyes treated with indirect photocoagulation, 4 of 15 eyes treated with sham photocoagulation, and none of the eyes treated with direct photocoagulation. This recurrence rate of 34% among patients not receiving direct photocoagulation compared with a 0% recurrence among patients treated with direct photocoagulation over the same I lh-year follow-up interval. This obvious difference is statistically valid.
DISCUSSION On the basis of the Mayo Clinic study, we concluded that indirect photocoagulation does not increase the outflow of subretinal fluid in a clinically relevant manner. Direct photocoagulation hastens restoration of normal function, possibly by promoting local debridement of the pigment epithelium, allowing neighboring pigment epithelial cells to cover the defect. Information from our study along with information from other studies has allowed us to suggest guidelines in management, as listed in Table I. I believe it is important to avoid treating the site of fluorescein dye leakage if it is much closer than 500 /-L from the capillary-free zone because other investigators have reported the development of subretinal neovascularization after photocoagulation of such cases. In cases where subretinal neovascularization has been observed to develop, treatment often had been associated with very small burns, 50-100 /-L in diameter,
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Table 1. Central Serous Chorioretinopathy: Management Recommendations • Individualize treatment • 4-month waiting period usually appropriate • Consider Rx if: Symptoms significantly interfere with required visual function There is evidence of microarchitectural changes in macular retina The best corrected visual acuity declines to 20/40 or less There are multiple recurrences • Avoid treating site of fluorescein dye leakage if within l disc parameter of fovea • If treating with argon laser when leakage site is l disc diameter or greater from fovea use: 100-200-Jl spot size 75-100 mW 0.2-second exposure
directed very close to the capillary-free zone. For this reason, I prefer to reserve argon laser-treatment for those cases in which the site of fluorescein dye leakage is 500 Jl
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or more from the capillary-free zone, in which instances spot sizes 200 Jl in diameter are preferred. Spot sizes less than 100 Jl should not be used. Our study demonstrated that low powers, enough to produce minimal graying of the pigment epithelium, are adequate to promote early resolution ofCSR. Generally, two or three 200-Jl-diameter spots with powers of approximately 100 m W or slightly less and exposure times of 0.2 seconds are all that is necessary to obtain a satisfactory result.
REFERENCES 1. Watzke RC, Burton TC, Leaverton PE. Hruby laser photocoagulation therapy of central serous retinopathy. Part I: A controlled clinical study. Part II: Factors affecting prognosis. Trans Am Acad Ophthalmol Otolaryngol 1974; 78:0P205-11. 2. Wessing A. Central serous retinopathy and related lesions. Mod Probl Ophthalmol1971; 9:148-51. 3. Watzke RC, Burton TC, Woolson RF. Direct and indirect laser photocoagulation of central serous choroidopathy. Am J Ophthalmol1979; 88:914-8. 4. Robertson DM, IIstrup D. Direct, indirect, and sham laser photocoagulation in the management of central serous chorioretinopathy. Am J Ophthalmol 1983; 95:457-66.
Abstract: Central serous chorioretinopathy, a sporadic self-limited disease of young adults, is associated with loss of central vision, image distortion, and impaired dark adaptation. The diagnosis is verified with fluorescein angiography, which demonstrates an expanding point of fluorescein dye leakage under a serous detachment of the sensory retina. Treatment should ordinarily be delayed four or more months but may be considered if there is evidence of microarchitectural changes in the macular retina, if the best corrected visual acuity declines to 20/40 or less, or if there have been multiple recurrences. Argon laser photocoagulation should be directed to the leakage site, using spot sizes of 200 f..L in diameter, exposure times of 0.2 seconds, and low-power intensities. [Key words: central serous chorioretinopathy, direct laser photocoagulation, indirect laser photocoagulation, laser photocoagulation.] Ophthalmology 93:972974, 1986
Central serous chorioretinopathy (CSR) is a sporadic disorder of unknown cause occurring in the eyes of young and middle-aged adults. It is characterized by the accumulation of serous fluid under the sensory retina, usually in the region of the macula. Patients often complain of blurred central vision image distortion (micropsia) and impaired dark adaptation. Spontaneous remission with near total visual recovery is the rule in CSR. Although the recovery time is unpredictable, vision usually recovers to normal or near normal within several months. Visual loss can be permanent if recovery time is prolonged or if recurrences are frequent. The diagnosis of CSR can be made clinically, but fluorescein angiography is necessary to rule out the presence of a subretinal neovascular membrane that may cause a serous detachment of the sensory retina that can mimic CSR. The fluorescein angiogram
From the Department of Ophthalmology, Mayo Clinic, Mayo Medical School, and Mayo Foundation, Rochester, Minnesota. Presented at an Annual Meeting of the American Academy of Ophthalmology. Supported in part by funds from Research to Prevent Blindness, Inc. and NEI grant EY01709. Reprint requests to Dennis M. Robertson, MD, Department of Ophthalmology, Mayo Clinic, Mayo Foundation, Mayo Medical School, Rochester, MN 55905.
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will identify in CSR a focal point of hyperfluorescence that usually expands symmetrically or, less commonly, asymmetrically so that the dye ascends and diffuses like smoke in the subretinal space. If the fluorescein angiogram shows a pattern suspicious for a subretinal neovascular membrane, the stereo angiography should be repeated in two to three weeks. If a subretinal neovascular membrane is present, it will likely become more obvious during the interval, making the diagnosis easier. The condition is not CSR if a hemorrhage is present, if a donut-shaped ring of pigmentation is visible at the level of the retinal pigment epithelium, or if there is a pit in the optic nerve. The diagnosis must be made with caution if the patient is 55 years of age or older or if there are multiple defects in the pigment epithelium. Even with a clinical and fluorescein angiographic appearance typical of CSR, I regard the condition in a patient 55 years of age or older as a subretinal neovascular membrane and treat the site of dye leakage with heavy photocoagulation as if it were a neovascular membrane. Spontaneous remission with near total visual recovery is the rule in CSR. Although the recovery time is unpredictable, vision usually recovers to normal or near normal within several months. Visual loss can be permanent if recovery time is prolonged or if recurrences are frequent. The first conclusive study to indicate that laser photocoagulation could be effective in the management of CSR was conducted by Watzke et al.I When the laser
ROBERTSON
•
CENTRAL SEROUS CHORIORETINOPATHY
treatment was directed to the site of fluorescein dye leakage, they found that the duration of the disease course could be shortened by an average of approximately two months. In spite of this shortened course, the final visual result did not appear to be significantly affected in their study. For most cases, laser photocoagulation directed to the leakage site is safe to use. However, if the site of fluorescein dye leakage is at or near the fovea, photocoagulation of this site will likely cause permanent visual loss. In such cases, Wessing suggested more than a decade ago that photocoagulation could be directed to any site under the serous detachment, in an area remote from the site of fluorescein dye leakage (so-called indirect photocoagulation), and that such indirect photocoagulation might be effective in promoting early absorption of the subretinal fluid. 2 Although there are some laboratory studies supporting the concept that such photocoagulation to the serious detachment away from the leak site might be effective, a randomized clinical study of CSR, conducted by Watzke et aI, indicated that indirect argon laser photocoagulation was inferior to direct argon laser photocoagulation. 3 In an effort to clarify the role oflaser photocoagulation in the management of CSR, we reported a prospective randomized clinical trial at the Mayo Clinic comparing treatment with direct, indirect, and sham argon laser photocoagulation in the management of CSR.4 This study repeated some of the work by Watzke et aI, comparing direct with indirect photocoagulation, but it also expanded their study by comparing indirect photocoagulation with a sham-treated control group. Our study also addressed the problem of recurrences.
MATERIALS AND METHODS In the Mayo Clinic study, eyes were stratified into two groups, depending on the site of fluorescein dye leakage. 4 Eyes in which the leakage site was found to be within the papillomacular bundle or within 500 /-L of the capillaryfree zone of the macula (an area for purposes of this study referred to as the critical zone) were stratified to group A. These eyes were then randomly assigned either a real indirect argon laser photocoagulation treatment or a sham treatment. Eyes in which the leakage site was outside the papillomacular bundle and more than 500 /-L from the capillary-free zone were stratified to group B. These eyes were randomly assigned either a direct or indirect argon laser photocoagulation. The indirect peripheral laser photocoagulation was directed to the pigment epithelium under the elevated retina at a site remote from both the sites of fluorescein dye leakage and the critical zone. Three burns 200 /-L in diameter with exposure times of 0.2 seconds and powers between 80 and 120 m W were used to produce minimally visible lesions at the level of the pigment epithelium. For eyes assigned to the sham photocoagulation group, a sham treatment was given through the contact lens with the aiming beam. Eyes assigned to the direct laser pho-
tocoagulation treatment group received burns similar in size and intensity to those delivered with the indirect photocoagulation technique. Having agreed to participate in the study and having signed a consent form, all patients were positioned at the laser, and a sealed envelope containing the randomized treatment assignment was opened. The disease was considered resolved when two examiners concluded on the same date that (1) subretinal fluid was absent on biomicroscopic examination, and (2) stereoscopic fluorescein angiograms showed no active leakage.
RESULTS A statistical analysis ofthe results of our study indicated that, of the 30 eyes in group A, there was no difference in weeks to resolution from the time the patient entered the study between the control group treated with sham laser photocoagulation and the group treated with indirect laser photocoagulation. 4 Of the 12 eyes in group B that were randomly assigned either direct photocoagulation or indirect photocoagulation, the results indicated that the direct laser photocoagulation shortened the duration of CSR by approximately two months, a difference that was not only statistically highly significant but that also compared almost identically to those figures reported by Watzke et al. l During a I lh-year follow-up, recurrences were observed in a total of 12 patients. In almost all instances, these recurrences occurred within 100 /-L of the original site of fluorescein dye leakage. Recurrences were recognized in 8 of the 20 eyes treated with indirect photocoagulation, 4 of 15 eyes treated with sham photocoagulation, and none of the eyes treated with direct photocoagulation. This recurrence rate of 34% among patients not receiving direct photocoagulation compared with a 0% recurrence among patients treated with direct photocoagulation over the same I lh-year follow-up interval. This obvious difference is statistically valid.
DISCUSSION On the basis of the Mayo Clinic study, we concluded that indirect photocoagulation does not increase the outflow of subretinal fluid in a clinically relevant manner. Direct photocoagulation hastens restoration of normal function, possibly by promoting local debridement of the pigment epithelium, allowing neighboring pigment epithelial cells to cover the defect. Information from our study along with information from other studies has allowed us to suggest guidelines in management, as listed in Table I. I believe it is important to avoid treating the site of fluorescein dye leakage if it is much closer than 500 /-L from the capillary-free zone because other investigators have reported the development of subretinal neovascularization after photocoagulation of such cases. In cases where subretinal neovascularization has been observed to develop, treatment often had been associated with very small burns, 50-100 /-L in diameter,
973
OPHTHALMOLOGY
•
JULY 1986 •
Table 1. Central Serous Chorioretinopathy: Management Recommendations • Individualize treatment • 4-month waiting period usually appropriate • Consider Rx if: Symptoms significantly interfere with required visual function There is evidence of microarchitectural changes in macular retina The best corrected visual acuity declines to 20/40 or less There are multiple recurrences • Avoid treating site of fluorescein dye leakage if within l disc parameter of fovea • If treating with argon laser when leakage site is l disc diameter or greater from fovea use: 100-200-Jl spot size 75-100 mW 0.2-second exposure
directed very close to the capillary-free zone. For this reason, I prefer to reserve argon laser-treatment for those cases in which the site of fluorescein dye leakage is 500 Jl
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NUMBER 7
or more from the capillary-free zone, in which instances spot sizes 200 Jl in diameter are preferred. Spot sizes less than 100 Jl should not be used. Our study demonstrated that low powers, enough to produce minimal graying of the pigment epithelium, are adequate to promote early resolution ofCSR. Generally, two or three 200-Jl-diameter spots with powers of approximately 100 m W or slightly less and exposure times of 0.2 seconds are all that is necessary to obtain a satisfactory result.
REFERENCES 1. Watzke RC, Burton TC, Leaverton PE. Hruby laser photocoagulation therapy of central serous retinopathy. Part I: A controlled clinical study. Part II: Factors affecting prognosis. Trans Am Acad Ophthalmol Otolaryngol 1974; 78:0P205-11. 2. Wessing A. Central serous retinopathy and related lesions. Mod Probl Ophthalmol1971; 9:148-51. 3. Watzke RC, Burton TC, Woolson RF. Direct and indirect laser photocoagulation of central serous choroidopathy. Am J Ophthalmol1979; 88:914-8. 4. Robertson DM, IIstrup D. Direct, indirect, and sham laser photocoagulation in the management of central serous chorioretinopathy. Am J Ophthalmol 1983; 95:457-66.