Background: Although peripapillary subretinal neovascular membranes (P
SRNs) are less common and often larger than neovascular complexes aris
ing near the fovea, they may lead to severe visual loss. Very large (m
assive) PSRNs (MPSRNs) are 3.5 disc areas or greater in overall size,
are even less common, and may contain a significant occult component,
leading to slow and unpredictable growth. Such massive lesions may beg
in at the nasal margin of the disc and do not become symptomatic until
they have extended around the disc toward the macula, threatening cen
tral vision. Although complete laser ablation has been used for sympto
matic PSRNs with variable success, the optimal treatment of MPSRNs rem
ains controversial. Methods: The authors reviewed the clinical course
of 12 eyes of seven patients with MPSRNs. Ten eyes received laser trea
tment, which was limited to the temporal portion of the subretinal neo
vascular complexes only and two received no treatment. Results: Of the
ten eyes receiving laser treatment, six showed stabilization of visua
l acuity, whereas in four the neovascular membrane progressed beneath
the fovea with severe visual loss. In the two untreated eyes, the subr
etinal neovascular membrane progressed beneath the macula with the los
s of central vision. Conclusions: In contrast to the small symptomatic
PSRNs, which are usually treated by complete laser ablation, MPSRNs m
ay stabilize with only partial laser treatment. However, both types of
lesions may remain stable for long periods of time without any treatm
ent and require treatment only if progression toward the fovea occurs.