Reprinted from
American Journal of Ophthalmology

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MEO.A)O. 2462

Vol. 107, No. 2, February 15, 1989

Large Optic Disks in the Marshallese Population


James M. Maisel, M.D., Caryn S. Pearlstein, M.D., William H. Adams, M.D.,

and Peter M. Heotis, M.P.S.

On routine examination, asymptomatic pa-

tients from the Marshall Islands were noted to
have large optic disks associated with high
cup/disk ratios and normal intraocular pressure. We retrospectively analyzed color fundus

photographs of 54 eyes and 22 eyes of 15
patients had optic disks greater than 2.10 mm,
or megalopapilla. Of 36 patients with cup/disk
ratios exceeding 0.6, 31 (86%) had visual acuities of better than or equal to 20/30. The optic

nerve rim and disk areas varied directly as did
disk and cup diameters. Three large disks with

an 18-year photographic follow-up showed no
change. Optic disk characteristics can vary
widely among genetically isolated populations.

DURING ROUTINE ophthalmologic examination of a Micronesian population in the Republic of the Marshall Islands, a striking numberof
patients were noted to have large optic disks.
These disks were associated with high cup/disk
ratios without increased intraocular pressures,
other disk anomalies, or any other ocular complaints.' This Pacific atoll population, which
may be considered genetically isolated, demonstrates a large number of people with megalopapilla.
Fundus photographs were obtained on a
group of patients noted to have high cup/disk
ratios as well as on a randomly selected group
of control patients. We performed a masked
Accepted for publication Oct. 14, 1988.
From the Department of Ophthalmology, School of
Medicine, State University of New York at Stony Brook,
Stony Brook, New York (Drs. Maisel and Pearlstein) and
the Medical Department, Brookhaven National Laboratories, Upton, New York (Drs. Adams and Heotis).
This project was supported in part by the U.S. Deparment of Energy under Contract No. DE-AC0Q276CHO00016. Accordingly, the U.S. Governmentretains a
nonexclusive, royalty-free license to publish or reproduce the published form of this contribution or allow
others to do so for U.S. Government purposes.
Reprint requests to James M. Maisel, M.D., 400 S.
Oyster Bay Rd., Suite 305, Hicksville, NY 11801-3516.

retrospective analysis of the fundus photographs in order to demonstrate that the optic
disks that appeared on ophthalmoscopic examination to have high cup/disk ratios were actually larger than those optic disks judged clinically normal on ophthalmoscopy.
Subjects and Methods
The population examined consisted of 141
adults native to the Marshall Islands. Some had
a history of radiation exposure in 1954, andit is
to provide diagnosis and care of radiationrelated illness that complete physical examinations are performed annually.” However, many
unexposed patients are also examined. All examinees receive ophthalmologic evaluation, including slit-lamp examination, biennially. Visual acuities are measured with a Snellen chart
at 20 feet. For this study there was noselection
based on age, sex, previous radiation exposure,
consanguinity, or ocular complaints or
findings. The ocular examination was performed by an ophthalmologist (J.M.M.} who
was part of the Brookhaven National Laboratory medical team. He completed a standardized
examination form for each patient as well as
performed the fundus photography. All patients thought to have abnormally large disks
or high cup/disk ratios underwent fundus photography, as did many patients with normal
disks who served as controls. Fundus photographs were taken in a total of 63 patients. The
photographs were given to a masked observer
(C.S.P.) for analysis.
Color slides of the optic nerve head taken
with a fundus camera were projected onto the
screen of a slide viewer. Using a ruler, meas-

urements were madedirectly from the projected image. Black and white photographsof the
optic disks of three patients were available
from 1967, and measurements madedirectly
from these photographs were compared to
those of 1985.




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