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Figure 3
The most common type 1 posterior
staphyloma. The edge of the
staphylomatous region is arrowed
progressive and result in vision loss 16 .
Steidl and Pruett 17 found that eyes with the
shallowest staphylomas showed the largest
drop in visual acuity as well as the greatest
frequency of choroidal neovascular membranes
and haemorrhage. They suggested that with
less advanced staphylomas, the choriocapillaris
was better preserved, thus increasing the
likelihood of the development of neovascular
membranes.
Lacquer cracks
Lacquer cracks, thought to be healed linear
ruptures in the retinal pigment epithelium-
Bruch’s membrane-choriocapillaris complex 18 ,
are present in about 4% of highly myopic eyes 19
(Figure 4). They are frequently seen in
conjunction with posterior staphylomas and up
to a third can have associated neovascular
membranes. The resolution of any resultant
haemorrhage may lead to the formation of a
pigmented Fuchs’ spot (Figure 5). Lacquer
cracks often progress to form more advanced
fundus changes 19 . Patients with lacquer cracks
and/or Fuchs’ spot should receive a guarded
prognosis for vision.
Chorioretinal atrophy
More commonly seen in the younger myope,
these areas appear as small, punched-out
yellow/white lesions in the presence of
posterior staphylomas, and potentially close to
lacquer cracks and the macula (Figure 6). With
time, smaller lesions frequently coalesce to
form larger areas 20 (Figure 7). Chorioretinal
atrophy may be the result of stretching and
thinning of the retinal pigment epithelium and
choroid as the eye enlarges, thus exposing the
sclera 21 .
FUNDUS PERIPHERY
The major threat to vision in the myopic eye is
retinal detachment, especially as posterior
vitreous detachment (PVD) and predisposing
retinal degenerations, such as lattice
degeneration, are more common in these eyes.
Figure 4
Lacquer cracks near the macula
Akiba 22 suggested that in high myopia, PVD
develops increasingly with age and the degree
of myopia, and that it may be seen as much as
10 years earlier in highly myopic eyes
compared to emmetropic eyes. In a study of
218 patients with myopia of six dioptres or
more in both eyes, Celorio and Pruett 23 found
that one third had lattice degeneration, with
the greatest prevalence being in eyes having
six to nine dioptres of myopia. Lattice
degeneration represents vulnerable areas of
retinal thinning. It is non-age specific and is
seen in about 40% of eyes with retinal
detachment 9 .
Pigmentary degeneration, consisting of
extensive pigment deposition in the extreme
retinal periphery, and the non-predisposing
paving stone degeneration (yellow-white areas
of chorioretinal thinning) are also more
common in myopic eyes. The pigment
proliferation and RPE migration of pigmentary
degeneration may be due to retinal traction,
while the chorioretinal thinning in paving
stone degeneration may be due to localised
occlusion of the choroidal circulation 16 . White
without pressure (translucent whitish
Figure 6
Chorioretinal atrophy: small, punched out
lesions near the macula (the white streak at
the bottom of the photograph is artefact)
Figure 5
A developing Fuchs’ spot together with
haemorrhage and a serous detachment of
the macula. Vision was markedly reduced
circumferential patches), from a prominent
vitreous base and mild vitreous traction, is
more frequently seen in myopic eyes and
occasionally retinal breaks can occur in the
presence of such lesions 9,16 .
It has been estimated that potentially up to
80% of eyes suffering retinal detachment have
some degree of myopia. Also, a person with
five dioptres of myopia is at a 15 times greater
risk of developing retinal detachment than an
emmetrope. With 20 dioptres of myopia, the
risk increases to 110 times 7 . There are also
reports of retinal detachments in myopes
following clear lens extraction procedures used
to refractively correct the myopia 24 .
MANAGEMENT
Myopic patients, especially those with
pathological myopia, must be reviewed
regularly, preferably on an annual basis, and
always through dilated pupils. They should
receive appropriate warnings of signs
and symptoms that may indicate a
sight-threatening situation is developing,
and be advised to utilise protective eyewear in
Figure 7
Chorioretinal atrophy: larger geographic
areas involving the posterior pole
34
March 22, 2002 OT
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