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Laser treatment of macular diseases
Ophthalmology Volume 105, Number 9, September 1998 Table 1. Results of Sub-Tenon’s and Retrobulbar Corticosteroids on Visual Acuity Based on Time after Surgery when Administered
Treatment
Time after Surgery (mos)
Pre-treatment VA
Sub-Tenon’s Retrobulbar Combined Sub-Tenon’s Retrobulbar Combined Sub-Tenon’s Retrobulbar Combined
ⱕ2 ⱕ2 ⱕ2 3–5 3–5 3–5 ⱖ6 ⱖ6 ⱖ6
20/88 20/183 20/114 20/109 20/60 20/97 20/56 20/76 20/69
Best VA
Time to Best VA after Last Injection (mos)
Final VA
Final Follow-up (mos)
20/52 20/66 20/57 20/47 20/31 20/43 20/33 20/43 20/40
1.6 7.2 3.6 3.8 5.8 4.2 8.0 3.6 5.1
20/61 20/66 20/63 20/61 20/31 20/53 20/41 20/79 20/63
9.0 22.3 13.7 8.3 12.5 9.1 12.5 12.5 12.5
VA ⫽ visual acuity.
tive study would allow us to better understand the optimal time for treatment. ALLEN B. THACH, MD Washington, DC PRAVIN U. DUGEL, MD Phoenix, Arizona JACK O. SIPPERLEY, MD Portland, Oregon SCOTT R. SNEED, MD Mesa, Arizona
Laser Treatment of Macular Diseases Dear Editor: In their article, “The Treatment of Macular Diseases Using a Micropulsed and Continuous Wave 810-nm Diode Laser” (Ophthalmology 1997;104:2030 –38), Friberg and Karatza verified the efficacy of a diode laser emitting in the nearinfrared spectrum in the treatment of retinal and choroidal vascular diseases. The authors state that if direct closure of retinal microaneurysms is the treatment goal, the nearinfrared wavelength of the diode laser would not be a logical choice. Therefore the authors did not specifically target microaneurysms but administered a grid pattern to the areas of retinal thickening. On the contrary, in a study on diabetic macular edema, Ulbig et al1 directly treated retinal microaneurysms with the near-infrared diode. In both studies the resolution of the retinal edema and the reduction of retinal microaneurysms were clearly noted. We recently reported similar positive results in the treatment of choroidal neovascular membranes with the same wavelength.2 These experiences with the diode laser raise an important point with respect to the mechanism responsible for the closure of vascular lesions of the retina and choroid after laser thermal photocoagulation. Direct absorption of radiation by hemoglobin within focal vascular lesions responsible for diabetic macular edema is thought to play a major role in the efficacy of the treatment.3 This mechanism is certainly valid in nonpigmented tissues, such as the mesentery, where hemoglobin is the primary absorption target. In this case blood flow stasis does not follow the classic hemostatic pathway but occurs by heat coagulation of fibrinogen and appears to be less stable. In the eye, retinal and
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choroidal pigmented cells are the most important targets during photocoagulation with the near-infrared wavelength. Retinal pigment epithelium and choroid melanocytes and retinal pigment epithelium alone absorb, respectively, 35% and 7% of the radiation, whereas oxyhemoglobin or reduced hemoglobin practically do not absorb the radiation at threshold energies. Therefore the near-infrared wavelength has unfavorable characteristics for the occlusion of retinal vascular lesions through the direct absorption of the radiation by hemoglobin. Despite this evidence, we recently showed that the diode laser was effective in inducing the closure of retinal macroaneurysms after photocoagulation placing one to two rows of burns around the lesion. The macroaneurysms were not directly covered with photocoagulation and no signs of blood flow stasis were evident during treatment [Invest Ophthalmol Vis Sci 38(Suppl):86, 1997]. A rationale other than that of direct coagulation has to explain the closure or obliteration of vascular lesions after irradiation with the 810-nm wavelength. They may close as a result of indirect treatment effects. Thus the mechanisms underpinning the efficacy of photocoagulation could be reconsidered according to the cited biophysical characteristics of the near-infrared radiation. Recent experiments demonstrated that the retinal pigment epithelium plays a role in the occlusion of vascular lesions of the retina and choroid. Laser burns in diabetic humans that involved only the outer retinal half but spared the inner nuclear layer, showed proliferation of pigment epithelial and glial cells that resulted in the closure of the leakage sites.3 The involution of subretinal neovascular membranes has been associated with retinal pigment epithelium proliferation that envelopes the new vessels.4 Finally, there is clear evidence that the beneficial effect of retinal photocoagulation is mediated by factors derived from the retinal pigment epithelium, such as transforming growth factor-2, which is known to modulate both fibrinogenesis and vascular proliferation in vivo and transforming growth factor-1, which has an effect on the permeability of retinal capillary endothelial cells [Invest Ophthalmol Vis Sci 38 (Suppl):754, 1997]. PAOLO LANZETTA, MD Udine, Italy
Letters to the Editor References 1. Ulbig MW, McHugh DA, Hamilton AM. Diode laser photocoagulation for diabetic macular oedema. Br J Ophthalmol 1995;79:318 –21. 2. Lanzetta P, Virgili G, Menchini U. Diode laser photocoagulation of choroidal neovascular membranes. Int Ophthalmol 1996;19:347–54. 3. Wallow IHL, Bindley CD. Focal photocoagulation of diabetic macular edema: a clinicopathologic case report. Retina 1988; 8:261–9. 4. Miller H, Miller B, Ryan SJ. The role of retinal pigment epithelium in the involution of subretinal neovascularization. Invest Ophthalmol Vis Sci 1986;27:1644 –52.
Authors’ reply Dear Editor: Dr. Lanzetta has amplified several important points concerning laser photocoagulation of the retina. In our article, we showed that grid laser photocoagulation alone using the infrared 810 diode wavelength is effective in the treatment of macular edema from diabetic retinopathy and branch retinal vein occlusion. We wholeheartedly agree that the physiologic response of the retina pigment epithelium to grid laser photocoagulation is very likely the salient event that leads to resolution of the retina edema. We too have observed improvement in the architecture of the retinal vasculature after diode laser photocoagulation of the retinal pigment epithelium in the vicinity of vascular abnormalities, such as microaneurysms and telangectasia. The mechanisms involved in the destruction of choroidal neovascular membranes are probably more complex than those involved in the resolution of macular edema, however. The historical concept that laser photocoagulation should be directed toward the destruction or the “sealing” of vascular tissues in order to achieve efficacy is simplistic and probably erroneous. We believe that newer laser strategies seeking to optimize the physiologic response to laser photocoagulation using minimal energy are more likely to yield improved visual results and result in fewer complications. We suggest that such strategies be considered carefully when treating retinal vascular diseases and choroidal neovascularization. Furthermore, dose-response considerations are particularly important when designing clinical trials that evaluate laser treatment of retinal disease, and in particular those trials in which high-risk eyes with macular degeneration are treated prophylactically with photocoagulation. THOMAS R. FRIBERG, MD EKATARINI KARATZA, MD Pittsburgh, Pennsylvania
Visual Acuity Outcomes with Appositional Suprachoroidal Hemorrhage Dear Editor: In their recent article on visual acuity outcomes among patients with appositional suprachoroidal hemorrhage (Ophthalmology 1997;104:2039 – 46), Scott et al did not discuss the role of systemic and/or topical steroids, if any, in improving the outcome of these difficult problems. After almost 25 years as an ophthalmologist, I recently experienced
my first choroidal hemorrhage in a cataract patient. A retina specialist colleague suggested high-dose systemic and topical steroids with a good outcome. I have the impression, based on this experience, that systemic steroids may accelerate the resolution of choroidal effusions. Do they have a role in the treatment of choroidal effusions or hemorrhages? It may be of interest to mention that, due to recent reimbursement cuts that seem to trivialize the risk, skill, and importance of cataract surgery, I had been considering discontinuing routine intraocular lenses. This particular case helped me to finalize my decision. JOHN K. HERPEL, MD Claremont, New Hampshire Authors’ reply Dr. Herpel raises an interesting question regarding the role of systemic and topical steroids in the treatment of patients with suprachoroidal hemorrhage. We reviewed the records of our patients with appositional suprachoroidal hemorrhage in our recent publication. None of our patients was treated with systemic steroids, but all patients received topical steroids before and/or after any secondary surgical intervention. Therefore, we cannot provide any analyses regarding the effectiveness of systemic steroids. In our recently reported series of 51 patients with appositional suprachoroidal hemorrhage, a final vision of preserved prehemorrhage vision or ⱖ20/200 was achieved in 8 of 27 patients (29.6%) who did not undergo a secondary surgical procedure and in 7 of 23 patients (30.4%) who did undergo secondary surgical management (one patient was treated with primary enucleation). Because complex ocular and medical conditions are frequently present among patients with appositional suprachoroidal hemorrhage, it would be difficult to subject such patients to a randomized prospective study evaluating the role of systemic steroids. We have seen spontaneous resolution of choroidal detachments (both serous and hemorrhagic) without the use of systemic steroids. Based on reported nonsurgical approaches to the treatment of choroidal detachment, the inflammatory component of serous choroidal detachment might theoretically be improved by systemic steroids. However, the theoretical benefit of systemic steroids in the management of hemorrhagic choroidal detachments, especially those of higher magnitude (appositional), is unclear. INGRID U. SCOTT, MD, MPH HARRY W. FLYNN, JR, MD WILLIAM E. SMIDDY, MD Miami, Florida Reference 1. Scott IU, Flynn HW Jr, Schiffman J, et al. Visual acuity outcomes among patients with appositional suprachoroidal hemorrhage. Ophthalmology 1997;104:2039 – 46.
Combined Chemoreduction and Adjuvant Treatment for Intraocular Retinoblastoma Dear Editor: We read with interest the recent report by Shields et al
1579
Treatment
Time after Surgery (mos)
Pre-treatment VA
Sub-Tenon’s Retrobulbar Combined Sub-Tenon’s Retrobulbar Combined Sub-Tenon’s Retrobulbar Combined
ⱕ2 ⱕ2 ⱕ2 3–5 3–5 3–5 ⱖ6 ⱖ6 ⱖ6
20/88 20/183 20/114 20/109 20/60 20/97 20/56 20/76 20/69
Best VA
Time to Best VA after Last Injection (mos)
Final VA
Final Follow-up (mos)
20/52 20/66 20/57 20/47 20/31 20/43 20/33 20/43 20/40
1.6 7.2 3.6 3.8 5.8 4.2 8.0 3.6 5.1
20/61 20/66 20/63 20/61 20/31 20/53 20/41 20/79 20/63
9.0 22.3 13.7 8.3 12.5 9.1 12.5 12.5 12.5
VA ⫽ visual acuity.
tive study would allow us to better understand the optimal time for treatment. ALLEN B. THACH, MD Washington, DC PRAVIN U. DUGEL, MD Phoenix, Arizona JACK O. SIPPERLEY, MD Portland, Oregon SCOTT R. SNEED, MD Mesa, Arizona
Laser Treatment of Macular Diseases Dear Editor: In their article, “The Treatment of Macular Diseases Using a Micropulsed and Continuous Wave 810-nm Diode Laser” (Ophthalmology 1997;104:2030 –38), Friberg and Karatza verified the efficacy of a diode laser emitting in the nearinfrared spectrum in the treatment of retinal and choroidal vascular diseases. The authors state that if direct closure of retinal microaneurysms is the treatment goal, the nearinfrared wavelength of the diode laser would not be a logical choice. Therefore the authors did not specifically target microaneurysms but administered a grid pattern to the areas of retinal thickening. On the contrary, in a study on diabetic macular edema, Ulbig et al1 directly treated retinal microaneurysms with the near-infrared diode. In both studies the resolution of the retinal edema and the reduction of retinal microaneurysms were clearly noted. We recently reported similar positive results in the treatment of choroidal neovascular membranes with the same wavelength.2 These experiences with the diode laser raise an important point with respect to the mechanism responsible for the closure of vascular lesions of the retina and choroid after laser thermal photocoagulation. Direct absorption of radiation by hemoglobin within focal vascular lesions responsible for diabetic macular edema is thought to play a major role in the efficacy of the treatment.3 This mechanism is certainly valid in nonpigmented tissues, such as the mesentery, where hemoglobin is the primary absorption target. In this case blood flow stasis does not follow the classic hemostatic pathway but occurs by heat coagulation of fibrinogen and appears to be less stable. In the eye, retinal and
1578
choroidal pigmented cells are the most important targets during photocoagulation with the near-infrared wavelength. Retinal pigment epithelium and choroid melanocytes and retinal pigment epithelium alone absorb, respectively, 35% and 7% of the radiation, whereas oxyhemoglobin or reduced hemoglobin practically do not absorb the radiation at threshold energies. Therefore the near-infrared wavelength has unfavorable characteristics for the occlusion of retinal vascular lesions through the direct absorption of the radiation by hemoglobin. Despite this evidence, we recently showed that the diode laser was effective in inducing the closure of retinal macroaneurysms after photocoagulation placing one to two rows of burns around the lesion. The macroaneurysms were not directly covered with photocoagulation and no signs of blood flow stasis were evident during treatment [Invest Ophthalmol Vis Sci 38(Suppl):86, 1997]. A rationale other than that of direct coagulation has to explain the closure or obliteration of vascular lesions after irradiation with the 810-nm wavelength. They may close as a result of indirect treatment effects. Thus the mechanisms underpinning the efficacy of photocoagulation could be reconsidered according to the cited biophysical characteristics of the near-infrared radiation. Recent experiments demonstrated that the retinal pigment epithelium plays a role in the occlusion of vascular lesions of the retina and choroid. Laser burns in diabetic humans that involved only the outer retinal half but spared the inner nuclear layer, showed proliferation of pigment epithelial and glial cells that resulted in the closure of the leakage sites.3 The involution of subretinal neovascular membranes has been associated with retinal pigment epithelium proliferation that envelopes the new vessels.4 Finally, there is clear evidence that the beneficial effect of retinal photocoagulation is mediated by factors derived from the retinal pigment epithelium, such as transforming growth factor-2, which is known to modulate both fibrinogenesis and vascular proliferation in vivo and transforming growth factor-1, which has an effect on the permeability of retinal capillary endothelial cells [Invest Ophthalmol Vis Sci 38 (Suppl):754, 1997]. PAOLO LANZETTA, MD Udine, Italy
Letters to the Editor References 1. Ulbig MW, McHugh DA, Hamilton AM. Diode laser photocoagulation for diabetic macular oedema. Br J Ophthalmol 1995;79:318 –21. 2. Lanzetta P, Virgili G, Menchini U. Diode laser photocoagulation of choroidal neovascular membranes. Int Ophthalmol 1996;19:347–54. 3. Wallow IHL, Bindley CD. Focal photocoagulation of diabetic macular edema: a clinicopathologic case report. Retina 1988; 8:261–9. 4. Miller H, Miller B, Ryan SJ. The role of retinal pigment epithelium in the involution of subretinal neovascularization. Invest Ophthalmol Vis Sci 1986;27:1644 –52.
Authors’ reply Dear Editor: Dr. Lanzetta has amplified several important points concerning laser photocoagulation of the retina. In our article, we showed that grid laser photocoagulation alone using the infrared 810 diode wavelength is effective in the treatment of macular edema from diabetic retinopathy and branch retinal vein occlusion. We wholeheartedly agree that the physiologic response of the retina pigment epithelium to grid laser photocoagulation is very likely the salient event that leads to resolution of the retina edema. We too have observed improvement in the architecture of the retinal vasculature after diode laser photocoagulation of the retinal pigment epithelium in the vicinity of vascular abnormalities, such as microaneurysms and telangectasia. The mechanisms involved in the destruction of choroidal neovascular membranes are probably more complex than those involved in the resolution of macular edema, however. The historical concept that laser photocoagulation should be directed toward the destruction or the “sealing” of vascular tissues in order to achieve efficacy is simplistic and probably erroneous. We believe that newer laser strategies seeking to optimize the physiologic response to laser photocoagulation using minimal energy are more likely to yield improved visual results and result in fewer complications. We suggest that such strategies be considered carefully when treating retinal vascular diseases and choroidal neovascularization. Furthermore, dose-response considerations are particularly important when designing clinical trials that evaluate laser treatment of retinal disease, and in particular those trials in which high-risk eyes with macular degeneration are treated prophylactically with photocoagulation. THOMAS R. FRIBERG, MD EKATARINI KARATZA, MD Pittsburgh, Pennsylvania
Visual Acuity Outcomes with Appositional Suprachoroidal Hemorrhage Dear Editor: In their recent article on visual acuity outcomes among patients with appositional suprachoroidal hemorrhage (Ophthalmology 1997;104:2039 – 46), Scott et al did not discuss the role of systemic and/or topical steroids, if any, in improving the outcome of these difficult problems. After almost 25 years as an ophthalmologist, I recently experienced
my first choroidal hemorrhage in a cataract patient. A retina specialist colleague suggested high-dose systemic and topical steroids with a good outcome. I have the impression, based on this experience, that systemic steroids may accelerate the resolution of choroidal effusions. Do they have a role in the treatment of choroidal effusions or hemorrhages? It may be of interest to mention that, due to recent reimbursement cuts that seem to trivialize the risk, skill, and importance of cataract surgery, I had been considering discontinuing routine intraocular lenses. This particular case helped me to finalize my decision. JOHN K. HERPEL, MD Claremont, New Hampshire Authors’ reply Dr. Herpel raises an interesting question regarding the role of systemic and topical steroids in the treatment of patients with suprachoroidal hemorrhage. We reviewed the records of our patients with appositional suprachoroidal hemorrhage in our recent publication. None of our patients was treated with systemic steroids, but all patients received topical steroids before and/or after any secondary surgical intervention. Therefore, we cannot provide any analyses regarding the effectiveness of systemic steroids. In our recently reported series of 51 patients with appositional suprachoroidal hemorrhage, a final vision of preserved prehemorrhage vision or ⱖ20/200 was achieved in 8 of 27 patients (29.6%) who did not undergo a secondary surgical procedure and in 7 of 23 patients (30.4%) who did undergo secondary surgical management (one patient was treated with primary enucleation). Because complex ocular and medical conditions are frequently present among patients with appositional suprachoroidal hemorrhage, it would be difficult to subject such patients to a randomized prospective study evaluating the role of systemic steroids. We have seen spontaneous resolution of choroidal detachments (both serous and hemorrhagic) without the use of systemic steroids. Based on reported nonsurgical approaches to the treatment of choroidal detachment, the inflammatory component of serous choroidal detachment might theoretically be improved by systemic steroids. However, the theoretical benefit of systemic steroids in the management of hemorrhagic choroidal detachments, especially those of higher magnitude (appositional), is unclear. INGRID U. SCOTT, MD, MPH HARRY W. FLYNN, JR, MD WILLIAM E. SMIDDY, MD Miami, Florida Reference 1. Scott IU, Flynn HW Jr, Schiffman J, et al. Visual acuity outcomes among patients with appositional suprachoroidal hemorrhage. Ophthalmology 1997;104:2039 – 46.
Combined Chemoreduction and Adjuvant Treatment for Intraocular Retinoblastoma Dear Editor: We read with interest the recent report by Shields et al
1579