Macular scatter ('grid') laser treatment of poorly demarcated subfoveal choroidal neovascularization in age-related macular degeneration. Results of a randomized pilot trial
N. M. Bressler, M. G. Maguire, P. L. Murphy, J. Alexander, R. Margherio, A. P. Schachat, S. L. Fine, T. S. Stevens and S. B. Bressler
Retinal Vascular Center, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Md, USA.
OBJECTIVES: 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. DESIGN:
Randomized pilot clinical trial. SETTING: Two tertiary care retinal
referral practices. PATIENTS: 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.
MAIN OUTCOME MEASURE: Change in visual acuity from baseline to specified
time periods. RESULTS: 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. CONCLUSIONS: 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.
