Sublaxation And Lens Dislocation

Subluxation
It is partial displacement in which lens is moved
sideways (up, down, medially or laterally), but remains
behind the pupil. It results from partial rupture or
unequal stretching of the zonules (Fig. 8.30 and
8.31A).

Clinical feautres are as follows
Defective vision occurs due to marked astigmatism
or lenticular myopia.
Uniocular diplopia may result from partial
aphakia.
Anterior chamber becomes deep and irregular.
Iridodonesis is usually present.
Dark edge of the subluxated lens is seen on
distant direct ophthalmoscopy
Complications of subluxated lens include :
Complete dislocation,
Cataractous changes,
Uveitis and
Secondary glaucoma.
Management. Spectacles or contact lens correction
for phakic or aphakic area (whichever is better) is
helpful in many cases. Surgery is controversial and
usually associated with high risk of retinal
detachment. Lensectomy with anterior vitrectomy
may be performed in desperate cases.
II. Dislocation or luxation of the lens
In it all the zonules are severed from the lens. A
dislocated lens may be incarcerated into the pupil or
present in the anterior chamber (Fig. 8.31B), the
vitreous (Fig. 8.31C) (where it may be floating – lens
nutans; or fixed to retina – lens fixata), sub-retinal
space, subscleral space or extruded out of the globe,
partially or completely.
Clinical features of posterior dislocation. These
include: deep anterior chamber, aphakia in pupillary
area, and iridodonesis. Ophthalmoscopic examination
reveals lens in the vitreous cavity.
Clinical features of anterior dislocation are deep
anterior chamber and presence of lens in the anterior
chamber. Clear lens looks like an oil drop in the
aqueous.
Complications associated with dislocated lens are
uveitis and secondary glaucoma.
Management. A lens dislocated in the anterior
chamber and that incarcerated in the pupil should be
removed as early as possible. A dislocated lens from
the vitreous cavity should be removed only if it is
causing uveitis or glaucoma. From the vitreous cavity
lens can be removed after total vitrectomy, either with
the help of an insulated vitreous cryoprobe or by
aspiration facility of vitrectomy probe (only soft
cataract).