Signs & Symptoms of myopia

Clinical picture
Symptoms
1. Defective vision. There is considerable failure in visual function as the error is usually high.
Further, due to progressive degenerative changes, an uncorrectable loss of vision may occur.

2. Muscae volitantes i.e., floating black opacities in front of the eyes are also complained of by many patients. These occur due to degenerated liquified vitreous.

3. Night blindness may be complained by very high myopes having marked degenerative changes.
Signs
1. Prominent eye balls. The eyes are often prominent, appearing elongated and 
even
simulating an exophthalmos, especially in unilateral cases. The elongation of the eyeball mainly affects the posterior pole and surrounding area; the part of the eye anterior to the equator may be normal
(Fig. 1).

fig 1

2. Cornea is large.
3. Anterior chamber is deep.
4. Pupils are slightly large and react sluggishly to light.
5. Fundus examination reveals following
characteristic signs :
(a) Optic disc appears large and pale and at its
temporal edge a characteristic myopic crescent
is present (Fig. 2).

fig 2

 Sometimes peripapillary crescent encircling the disc may be present, where the choroid and retina is distracted away from the disc margin. A super-traction crescent (where the retina is pulled over the disc margin) may be present on the nasal side.

(b) Degenerative changes in retina and choroid are common in progressive myopia (Fig. 2).  

fig 3

                                         

These are characterised by white atrophic patches at the macula with a little heaping up of pigment around them. Foster-Fuchs' spot (dark red circular patch due to sub-retinal
neovas-cularization and choroidal haemorrhage) may be present at the macula.
Cystoid degeneration may be seen at the periphery. In an advanced case there occurs
total retinal atrophy, particularly in the central area.

(c) Posterior staphyloma due to ectasia of sclera at posterior pole may be apparent as an
excavation with the vessels bending backward over its margins.

(d) Degenerative changes in vitreous include: liquefaction, vitreous opacities, and posterior
vitreous detachment (PVD) appearing as Weiss' reflex.

 6. Visual fields show contraction and in some cases
ring scotoma may be seen.
7. ERG reveals subnormal electroretinogram due to
chorioretinal atrophy.