Modified Grid Laser Photocoagulation for Diffuse Diabetic Macular Edema Long-term Visual Results CAROL M. LEE, MD, R. JOSEPH OLK, MD
Abstract: The authors reviewed the records of 302 eyes of 185 patients with diffuse diabetic macular edema with or without cystoid macular edema treated with modified grid laser photocoagulation between the years 1981 and 1990. Three years after initial grid treatment, visual acuity was improved in 14.5%, unchanged in 60.9%, and worse in 24.6% of eyes. The average number of treatments per eye was 1.9. These results show that in assessing long-term visual outcome, modified grid laser photocoagulation is an effective modality in maintaining or improving visual acuity in eyes with diffuse diabetic macular edema. The effectiveness demonstrated in this study is without comparison with control subjects with no treatment or comparison with other treatment techniques. Ophthalmology 1991; 98:1594-1602
Diabetic macular edema is the most frequent cause of visual loss in patients with diabetic retinopathyY The prevalence of macular edema is directly correlated to the duration of diabetes 3•4 and is seen earlier in adult-onset diabetes. Reports from The Early Treatment Diabetic Retinop athy Study5 (ETDRS) demonstrated that focal treatment of"clinically significant" macular edema was effective in reducing the risk of visual loss. Patients received direct photocoagulation to focally leaking microaneurysms and/ or grid treatment to areas of diffuse macular edema. 5-7 Olk8- 12 previously reported the beneficial effects of modified grid laser photocoagulation in reducing visual Originally received: October 28, 1990. Revision accepted: June 19, 1991. From Retina Consultants, Ltd, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis.
loss in patients with diffuse diabetic macular edema. This treatment entails a grid pattern of photocoagulation in the parafoveal region up to and including the edge of the foveal avascular zone and to all areas of retinal thickening and/or capillary nonperfusion. Areas of focally leaking microaneurysms outside the areas of diffuse retinal thick ening are treated with direct photocoagulation. Obvious large microaneurysms are treated focally, but minute focal leaks within areas of diffuse thickening as seen only on fluorescein angiography are not treated directly. In two previous prospective, randomized clinical trials, Olk8•12 evaluated the efficacy of argon blue-green laser and the comparative differences of argon green versus krypton red laser photocoagulation. Visual results at 12 and 24-months follow-up were analyzed with regard to laser wavelength. In this report, we present long-term fol low-up on 302 eyes from those trials treated with modified grid laser photocoagulation for diffuse diabetic macular edema with follow-up of 2 to 9 years.
Dr. Lee is currently affiliated with the Department of Ophthalmology, New York University Medical Center, New York . Presented at the American Academy of Ophthalmology Annual Meeting, Atlanta, Oct/Nov 1990. Reprint requests to R. Joseph Olk, MD, Retina Consultants, Ltd, One Barnes Hospital Plaza, East Pavilion/Suite 17413, St. Louis, MO 63110.
1594
MATERIALS AND METHODS All patients were initially examined and treated by the same surgeon (RJO) between 1981 and 1988. Inclusion
LEE AND OLK
•
MODIFIED GRID LASER PHOTOCOAGULATION
criteria included a known diagnosis of Type I or Type II diabetes mellitus and diffuse macular edema with or without cystoid macular edema diagnosed on slit-lamp biomicroscopy and confirmed by stereo fundus photog raphy and 10% sodium fluorescein angiography. Diffuse macular edema was defined as retinal thickening of two or more disc are11s and involving some portion of the foveal avascular zone (FAZ). Only eyes with two or more disc areas of retinal thickening were eligible; any eye with less than two disc areas of retinal thickening, or retinal thickening not involving the F AZ was excluded. Before enrollment into the study, the following criteria had to be met: glycosylated hemoglobin equal to or less than 10.0 mg/dl, diastolic blood pressure less than 100 mmHg, and best-corrected visual acuity better than or equal to 20/200-3, as measured by an independent examiner using the ETDRS visual acuity chart at 4 meters. Patients with chronic renal failure maintained on renal dialysis were excluded. Patients with a diastolic blood pressure greater than 100 mmHg or whose glycosylated hemoglobin was greater than l 0.0 mg/dl were referred to their internist to be reconsidered for entry into the study 4 to 6 months later. Ophthalmologic exclusion criteria included all of the following: previous laser photocoagulation to within two disc diameters of the center of the macula; preretinal or vitreous hemorrhage at the time of evaluation for entry; history of retinal detachment or retinoschisis; significant media opacity; iris neovascularization; previous retinal or other intraocular surgery that could interfere with ade quate treatment or follow-up; cataract extraction or leris implantation within the previous 12 months; and a history of glaucoma or any other ocular disease that could affect the assessment of the treatment results. Eyes with one or two retinopathy risk factors, as defined by the Diabetic Retinopathy Study (DRS), 15 had only their macular edema treated; their proliferative disease was fol lowed until "high-risk" proliferative retinopathy devel oped at which time panretinal photocoagulation was in stituted. Eyes with three or four retinopathy risk factors at entry were treated one of two ways: ( 1) the eye was treated in two sessions with peripheral panretinal pho tocoagulation and when the proliferative diabetic reti nopathy regressed the macular edema was then treated according to the study protocol; (2) the eye was treated with a combination of peripheral panretinal photocoag ulation and modified g.
Abstract: The authors reviewed the records of 302 eyes of 185 patients with diffuse diabetic macular edema with or without cystoid macular edema treated with modified grid laser photocoagulation between the years 1981 and 1990. Three years after initial grid treatment, visual acuity was improved in 14.5%, unchanged in 60.9%, and worse in 24.6% of eyes. The average number of treatments per eye was 1.9. These results show that in assessing long-term visual outcome, modified grid laser photocoagulation is an effective modality in maintaining or improving visual acuity in eyes with diffuse diabetic macular edema. The effectiveness demonstrated in this study is without comparison with control subjects with no treatment or comparison with other treatment techniques. Ophthalmology 1991; 98:1594-1602
Diabetic macular edema is the most frequent cause of visual loss in patients with diabetic retinopathyY The prevalence of macular edema is directly correlated to the duration of diabetes 3•4 and is seen earlier in adult-onset diabetes. Reports from The Early Treatment Diabetic Retinop athy Study5 (ETDRS) demonstrated that focal treatment of"clinically significant" macular edema was effective in reducing the risk of visual loss. Patients received direct photocoagulation to focally leaking microaneurysms and/ or grid treatment to areas of diffuse macular edema. 5-7 Olk8- 12 previously reported the beneficial effects of modified grid laser photocoagulation in reducing visual Originally received: October 28, 1990. Revision accepted: June 19, 1991. From Retina Consultants, Ltd, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis.
loss in patients with diffuse diabetic macular edema. This treatment entails a grid pattern of photocoagulation in the parafoveal region up to and including the edge of the foveal avascular zone and to all areas of retinal thickening and/or capillary nonperfusion. Areas of focally leaking microaneurysms outside the areas of diffuse retinal thick ening are treated with direct photocoagulation. Obvious large microaneurysms are treated focally, but minute focal leaks within areas of diffuse thickening as seen only on fluorescein angiography are not treated directly. In two previous prospective, randomized clinical trials, Olk8•12 evaluated the efficacy of argon blue-green laser and the comparative differences of argon green versus krypton red laser photocoagulation. Visual results at 12 and 24-months follow-up were analyzed with regard to laser wavelength. In this report, we present long-term fol low-up on 302 eyes from those trials treated with modified grid laser photocoagulation for diffuse diabetic macular edema with follow-up of 2 to 9 years.
Dr. Lee is currently affiliated with the Department of Ophthalmology, New York University Medical Center, New York . Presented at the American Academy of Ophthalmology Annual Meeting, Atlanta, Oct/Nov 1990. Reprint requests to R. Joseph Olk, MD, Retina Consultants, Ltd, One Barnes Hospital Plaza, East Pavilion/Suite 17413, St. Louis, MO 63110.
1594
MATERIALS AND METHODS All patients were initially examined and treated by the same surgeon (RJO) between 1981 and 1988. Inclusion
LEE AND OLK
•
MODIFIED GRID LASER PHOTOCOAGULATION
criteria included a known diagnosis of Type I or Type II diabetes mellitus and diffuse macular edema with or without cystoid macular edema diagnosed on slit-lamp biomicroscopy and confirmed by stereo fundus photog raphy and 10% sodium fluorescein angiography. Diffuse macular edema was defined as retinal thickening of two or more disc are11s and involving some portion of the foveal avascular zone (FAZ). Only eyes with two or more disc areas of retinal thickening were eligible; any eye with less than two disc areas of retinal thickening, or retinal thickening not involving the F AZ was excluded. Before enrollment into the study, the following criteria had to be met: glycosylated hemoglobin equal to or less than 10.0 mg/dl, diastolic blood pressure less than 100 mmHg, and best-corrected visual acuity better than or equal to 20/200-3, as measured by an independent examiner using the ETDRS visual acuity chart at 4 meters. Patients with chronic renal failure maintained on renal dialysis were excluded. Patients with a diastolic blood pressure greater than 100 mmHg or whose glycosylated hemoglobin was greater than l 0.0 mg/dl were referred to their internist to be reconsidered for entry into the study 4 to 6 months later. Ophthalmologic exclusion criteria included all of the following: previous laser photocoagulation to within two disc diameters of the center of the macula; preretinal or vitreous hemorrhage at the time of evaluation for entry; history of retinal detachment or retinoschisis; significant media opacity; iris neovascularization; previous retinal or other intraocular surgery that could interfere with ade quate treatment or follow-up; cataract extraction or leris implantation within the previous 12 months; and a history of glaucoma or any other ocular disease that could affect the assessment of the treatment results. Eyes with one or two retinopathy risk factors, as defined by the Diabetic Retinopathy Study (DRS), 15 had only their macular edema treated; their proliferative disease was fol lowed until "high-risk" proliferative retinopathy devel oped at which time panretinal photocoagulation was in stituted. Eyes with three or four retinopathy risk factors at entry were treated one of two ways: ( 1) the eye was treated in two sessions with peripheral panretinal pho tocoagulation and when the proliferative diabetic reti nopathy regressed the macular edema was then treated according to the study protocol; (2) the eye was treated with a combination of peripheral panretinal photocoag ulation and modified g.
