A pilot randomized controlled study on the effect of laser photocoagulation of confluent soft macular drusen. Prophylactic laser treatment in early age related maculopathy reduced the incidence of exudative complications. Laser photocoagulation for macular soft drusen. Updated results. Macular scatter ('grid') laser treatment of poorly demarcated subfoveal choroidal neovascularization in age-related macular degeneration. Results of a randomized pilot trial. Indirect scatter laser photocoagulation to subfoveal choroidal neovascularization in age-related macular degeneration. Krypton laser photocoagulation for neovascular lesions of age-related macular degeneration. Results of a randomized clinical trial. Macular Photocoagulation Study Group.
The authors determined the effect of photocoagulation of drusen on visual acuity and progression to subretinal neovascular membranes (SRNV).
                One of paired eyes was randomized to photocoagulation with other eye to control in 27 patients having symmetrical maculopathy and visual acuities, aged 46 to 81 years (mean, 69.7 years); follow-up 1 to 6 years (mean, 3.2 years).
                Final visual acuity was improved in treated eye or decreased in control eye in 12 patients, equal in 13 patients, and decreased in treated eye in 2 patients (P < 0.006). Progression to SRNV was less with treatment.
                Laser photocoagulation of confluent soft macular drusen may improve long-term visual prognosis. To investigate the effect of prophylactic laser treatment on drusen area and incidence of exudative lesions in patients with soft drusen maculopathy.
                In a prospective study, patients with early age related maculopathy (ARM) and good visual acuity were randomized to laser treatment or to a control group. Each group consisted of two subgroups: a fellow eye group and a bilateral drusen group. At 3 years, 36 of 38 enrolled patients remained in the study. Photocoagulation was performed with an argon green laser, approximately 100 mild laser burns being placed on and between the drusen in a perifoveal temporal horseshoe-shaped area. Both cases and controls were subjected to fundus colour photographs and fluorescein angiograms at regular intervals, and the drusen area was calculated in both photographs and angiograms. At baseline, there were no significant differences (p > 0.3-0.8) in drusen area between the groups.
                In the treatment group, mean drusen area decreased significantly in the fundus photographs as well as in the angiograms (p < 0.001). Visual acuity and colour contrast sensitivity (CCS) did not change significantly. All these results are valid also for the subgroups. In the control group, however, mean drusen area increased significantly (p < 0.001). Mean visual acuity decreased significantly (p < 0.01) as did the colour contrast sensitivity along the tritan axis (p = 0.02). For the fellow eye control group (n = 7), the increase in drusen area in fundus photographs and the decrease in CCS along the tritan axis were not statistically significant (p = 0.57 and p = 0.37, respectively). Furthermore, at 3 years, five patients in the control group showed exudative lesions (1/7 in the fellow eye group and 4/12 in the bilateral drusen group), whereas no such complications occurred in the treatment group. One patient developed a small atrophy, however. Thus, there is now a significant difference (p = 0.047), however with a large 95% confidence interval, 0.06-0.46, regarding exudative complications between the treated group and the control group in our small patient material.
                Perifoveal mild laser treatment causes a reduction in drusen area in patients with soft drusen maculopathy and may lower the incidence of exudative lesions. To update the results of a study on the disappearance of macular soft drusen after laser treatment in the natural evolution of age-related macular degeneration.
                A total of 46 patients with confluent soft drusen and pigmentary changes were studied prospectively. Group 1 was composed of 30 patients with bilateral drusen; the authors randomly assigned one eye of each patient for treatment and the fellow eye for the control. In 16 patients a choroidal neovascular membrane was present in one eye, and treatment was applied to the fellow eye (group 2). Argon green laser treatment was applied directly to the soft drusen in the temporal macula.
                All treated drusen disappeared in a mean of 3.5 months after treatment, and untreated drusen disappeared in all but three patients in an average of 8.5 months. After an average period of 3 years, only one control eye and none of the treated eyes in group 1 developed a choroidal neovascular membrane (P = 0.500). In group 2, neovascularization occurred in 18% of the patients. The initial improvement in Snellen acuity after subfoveal drusen disappearance diminished as a consequence of cataract progression.
                Although no definitive conclusions should be made because of the small number of patients studied, results seem to show that this treatment does not reduce the risk of choroidal neovascularization in the treated eye of patients with a history of exudative disease in the fellow eye. It may be effective in patients with high-risk bilateral soft drusen, that is, in less advanced stages of the disease. To determine the effects of macular scatter ("grid") laser photocoagulation compared with observation on the visual function of eyes with subfoveal choroidal neovascularization (CNV) that has poorly demarcated boundaries and to provide preliminary data for the evaluation of the feasibility and design of a larger, definitive trial.
                Randomized pilot clinical trial.
                Two tertiary care retinal referral practices.
                Symptomatic individuals with subfoveal CNV secondary to age-related macular degeneration in whom fluorescein angiography showed occult CNV with poorly demarcated boundaries; classic CNV was allowed but did not need to be present for entry into the study.
                Change in visual acuity from baseline to specified time periods.
                Fifty-two eyes were assigned to observation. Fifty-one eyes were assigned randomly to treatment consisting of macular scatter ("grid") laser photocoagulation to the area of CNV. The treatment protocol for 8 of these eyes also included confluent laser photocoagulation to areas of classic CNV. The average visual acuity decrease from baseline was greater in the treated than in the observed group. The difference between these groups was greatest within the first year after study enrollment. At 24 months, slightly more than 40% of the eyes in each group had lost 6 or more lines of visual acuity. Similar results were noted for the subgroup of eyes initially with angiographic features of occult CNV but no classic CNV.
                These short-term study results suggest that macular scatter ("grid") laser treatment is not beneficial and is possibly harmful compared with observation for symptomatic subfoveal CNV with poorly demarcated boundaries in age-related macular degeneration. With or without treatment, a significant proportion of these patients are at risk of severe visual loss within 2 years of seeking treatment, even when the eye initially has occult CNV and no classic CNV. Occult choroidal neovascularization (CNV), poorly defined on fluorescein angiography, is present in the majority of patients with exudative complications of age-related macular degeneration. For patients who present with this type of subfoveal CNV but who have useful visual acuity, no form of treatment is of proven benefit. Accordingly, a pilot randomized trial of indirect laser treatment was performed. The rationale of this treatment was to inhibit the CNV through laser-induced effects on the retinal pigment epithelium.
                Patients with occult subfoveal CNV without retinal pigment epithelial detachment and with visual acuity of 20/200 or better were randomized to treatment or control groups. A grid of laser burns was applied to the macula beyond the area of serous retinal detachment and of angiographically defined occult CNV.
                After an average follow-up of 38 months, there was no difference in mean final visual acuity (0.12 treated, 0.14 control) or clinical outcome between treated and untreated groups. Fluorescein angiography showed gradual enlargement in the occult CNV in 58% of eyes in both groups. A decrease in visual acuity to worse than 20/200 (54% of treated, 50% of control eyes) was associated with ingrowth of well-delineated CNV (6 treated, 7 control eyes) or progression to a fibroglial or atrophic scar (11 treated, 8 control eyes).
                No benefit was demonstrated for scatter photocoagulation of the macula in patients with age-related macular degeneration and occult subfoveal CNV with initially good visual acuity. There were, however, no complications related to treatment. The Age-Related Macular Degeneration Study-Krypton Laser (AMDS-K) is a multicenter controlled clinical trial designed to determine whether krypton red laser photocoagulation is of value in preventing visual acuity loss in eyes with macular degeneration that have either choroidal neovascularization 1 to 199 microns from the center of the foveal avascular zone or choroidal neovascularization 200 microns or farther from the foveal avascular zone center with blood and/or blocked fluorescence extending within 200 microns of the foveal avascular zone center. Recruitment ended in December 1987 after 247 patients had been assigned to photocoagulation and 249 patients had been assigned to no treatment. At 3 years after randomization, 49% (86/174) of treated eyes, in contrast to 58% (98/169) of untreated eyes, had lost six or more lines of visual acuity. The average visual acuity of treated and untreated eyes at that time was 20/200 and 20/250, respectively. The benefit of laser treatment was largest among patients without evidence of hypertension and diminished to no apparent benefit among patients who had highly elevated blood pressure and/or used antihypertensive medication. Treatment of lesions meeting the AMDS-K eligibility criteria in eyes of patients with no hypertension is recommended. However, treatment cannot be recommended uniformly for patients with definite hypertension having lesions similar to those of patients enrolled in the AMDS-K.
The trials included in this review confirm the clinical observation that laser photocoagulation of drusen leads to their disappearance. However, there is no evidence that this subsequently results in a reduction in the risk of developing CNV, geographic atrophy or visual acuity loss.