includes various fundus changes in myopia

1. Dr. K. Vasantha M.S., F.R.C.S.,
Director RIO Chennai (Rtd)

2.  Myopia: it is a refractive condition in
the eye where the incident parallel rays
of light gets focused in front of the
retina when accommodation is at rest

3.  High myopia – autosomal recessive or
X linked
 Moderate myopia – autosomal
dominant
 Congenital stationary night blindness –
autosomal dominant or X linked

4. Is seen in
 Stickler’s syndrome
 Ehlers Danlos syndrome
 Marfan’s
 Noonan’s syndrome
 Down’s syndrome
 Knobloch’s syndrome with occipital
encephalocele

5.  If a person who had been an emmetrope
earlier says he can view near objects better
and is seen to have myopia suspect
diabetes. This is because due to hyper
glycemia the lens becomes swollen and the
person becomes myopic.
 Also arsenic poisoning, sulpha, B complex
usage and smoking

6.  Axial myopia- due to increase in axial length
 Index myopia due to changes in the refractive
index- E.G. nuclear sclerosis in old age
 Congenital myopia (also called developmental
myopia) – here the child is born with
abnormally long eye. Immediately after birth
the error will be -10 D or even more. This is
usually stationary
 Curvature myopia due to increase in corneal
curvature

7. META-PM classification
 No myopic retinal lesions – category 0
 Tessellated- category 1
 Diffuse chorio retinal atrophy – category 2
 Patchy chorio retinal atrophy – category 3
 Macular atrophy – category 4

8. Plus signs added to the above categories
 Lacquer cracks
 Myopia with choroidal neovascularization
 Fuchs’ spot

9.  This type of myopia starts very early –
around five to ten and progress up to or even
beyond 25 years of age.
 The degenerative changes start late and
becomes marked around the age of 50.
 More common in women

10.  If the refractive error is more than – 6 D and
/or the axial length is > 26.5mm it is called
high myopia.
 If degenerative changes are seen in the
retina it is called pathological myopia or
degenerative myopia.

11.  Tessellated fundus
 Chorio retinal atrophy either diffuse or focal
 Macular changes
 Posterior staphyloma
 Changes in the periphery

12.  The disc appears larger
 The physiological cup also is larger but the
neuro retinal rim will be normal. With this we
can differentiate it from glaucomatous
cupping

13.  Essentially atrophic and seen on the
temporal border of the disc. Rarely it can
surround the disc.
 Here the pigmentary epithelium stops short
of the disc and the choroid is atrophic
 On the nasal side the retina may be drawn on
to the disc – called super traction crescent

14.  This is progressive
 Thinning of choroid
 Loss of choroidal blood vessels
 Loss of photoreceptors and RPE due to loss
of blood supply

15.  This is usually seen around the disc
 May extend to the macula
 Then entire posterior pole
 FFA: Hyper fluorescence in the late phase
 ICGA: reduction in the number of choroidal
blood vessels
 OCT: thinning of the choroid in the area of
atrophy

17.  Well defined lesions which appear like
healed choroiditis patches esp. in the macula
and around the disc
 Loss of chorio capillaries, outer retina and
RPE
 As the lesion advances bare sclera is seen
 CNV, macular retinoschisis, retinal breaks
with detachment occur more often

18.  Lacquer cracks: due to breaks in the Bruch’s
membrane. Difficult to see with
ophthalmoscope. In ICGA cracks appear as
hypo fluorescent linear lesions.
 When cracks appear hemorrhage can occur.
If it is minimal it will disappear soon. If it is
thick it will persist and cause defects in the
outer retina, leading on to visual loss

19.  If it occurs close to the fovea vision will be
grossly affected
 It is a risk factor for choroidal
neovascularisation
 This is due to stretching of the sclera

20.  Raised pigmented lesion usually in the visual
axis .
 Proliferation of pigment epithelium with
hemorrhage

21.  Cause for CNV (usually type 2)in young
individuals
 Risk factors: Patchy chorio retinal atrophy,
steep posterior staphyloma and lacquer
cracks
 Even after treatment prognosis is poor as
there will be degenerative changes around
the CNV

22.  If there is sub retinal exudation it should be
considered as active lesion
 OCT: absence of Bruch’s membrane,
disruptions in the ellipsoid zone, absence of
external limiting membrane and retinal
thickening
 OCTA: lacy wheel pattern, numerous
capillaries with a halo around the lesion.
 Treatment – anti VEGF

23.  Dome shaped macula within the posterior
staphyloma
 If horizontal ridges are seen from the disc to
the macula in a case of posterior staphyloma
this should be suspected.
 Vitreo macular traction, choroidal or scleral
thickening (seen with OCT), hypotony and
retinal resistance to scleral deformation

24.  Reduction in visual acuity and
metamorphopsia
 Atrophic changes will be seen in the RPE
 Retinal detachment
 And CNV can occur

25.  Due to -tangential vitreous traction from
contraction of cortical vitreous and epiretinal
membrane
 Antero posterior traction because of
staphyloma
 Poor adhesion due to RPE atrophy
 OCT will be needed to differentiate from
lamellar hole, macular detachment and
macular retinoschisis

26.  Vitrectomy with ILM peeling along with gas
tamponade
 This will remove pre macular traction creating
factors like vitreous attachment, epiretinal
membrane, the scaffold for cellular
proliferation.
 Facilitates in increasing the flexibility of the
retina
 If there is a detachment macular buckle can be
tried

27.  When posterior staphyloma is present foveal
retinal detachment and retinoschisis can
ensue due to vitreous traction
 The splitting of retina is due to higher rigidity
of the inner retina (rigid ILM and retinal
vessels)compared to the outer retinal layers

28.  Split is at the level of external limiting
membrane
 Stiff vessels may cause retinal micro folds
also
 Vitrectomy has to be done

29.  This is due to the stretching of the thin retina
 Best seen with binocular ophthalmoscopy.
 A crescentic shadow of about 2 -3 D will be
seen temporal to the disc with change in the
course of the vessels.
 Above the age of 50
 Absence of normal choroidal flush shows that
this may be due to ischemia

30.  Lattice degeneration- abnormal thinning in the
peripheral retina.
 Oval or straight patches
 Single or multiple
 Usually binocular

31.  Pigment clumps are usually seen
 Sclerotic vessels form crossed hatch pattern –
hence the name lattice degeneration
 Atrophic holes may be seen
 Tears and holes also may form leading on to
retinal detachment

32.  May seen in normal eyes also
 Usually seen in myopes
 Ehlers Danlos
 Marfan’s and Stickler’s

33.  Snail track degeneration – pin point white dots
in rows
 ? May be early lattice
 Cystoid degenerations may also be seen in the
periphery

34.  It is corrected with minus or concave lenses.
 Can be corrected with spectacles or contact
lenses. With contact lenses side vision will
be better. This is essential in high myopia.
 Laser corrections are also done.

35.  It is better to slightly under correct myopia
by about 0.25 D, but if they have exophoria
full correction must be given
 The concave lenses act as base out prisms
and hence it reduces the amount of
convergence and accommodation needed for
near vision

36.  This can be done with orthokeratology lenses. These
lenses worn overnight will displace the epithelium
and cause thinning of the cornea in the center
thereby correcting the myopia during the day time.
But the peripheral vision still remains blurred and
this may be the reason for the reduction in the
growth of the eye.
 Very diluted atropine drops are also used to prevent
progression of myopia

37.  AIOS Times Issue 1,2019
 Duke Elder’s Refraction