- Commonest type of acquired cataract.
Factors responsible for senile cataract :
- Higher concentration of UV rays in tropical su-light.
- Nutritional deficiency factors (vitamin A,C & E)
MORPHOLOGICAL TYPES OF SENILE CATARCT
1. Cortical senile cataract (soft cataract)- Opacities in cortex may be of two types:
- Cuneiform cataract: Wedge shaped opacities (spokes) in the cortex.
- Posterior subscapular (Cupuliform) cataract: Saucer shaped opacity under the posterior capsule.
2. Nuclear senile cataract (Hard cataract): Opacity in the nucleus
- Most common type of senile cataract is cuneiform cortical (70%) followed by nuclear (25%) & cupuliform.
MATURATION OF CATARACT
A) Maturation if the cortical type of senile cataract
1. Stage of lamellar separation:
- The earliest senile change is demarcation of cortical fibres owing to their separation by fluid.
- These changes are reversible.
2. Stage of incipient cataract:
- In this stage early detectable opacities with clear areas b/w them are seen.
- Two distinct types of senile cortical cataracts can be recognized at this stage:
a) Cuneiform senile cortical cataract-
- Characterized by wedge-shaped opacities with clear areas in between.
- On oblique illumination these present a typical radial spoke- like pattern of grayish white opacities.
b) Cupuliform senile cortical cataract (Posterior subcapsular)-
- Saucer shaped opacity develops just below the capsule.
- Usually in the central part of posterior cortex (posterior subcapsular cataract), which gradually extent outwards.
- Cupuliform cataract lies right in the pathway of the axial rays & thus causes an early loss of visual acquity.
- Loss of vision is early in bright light as there is constriction of pupil & opacity is in the center.
3. Immature senile cataract (ISC):
- In this stage, opacification progresses further.
- In some patients, at this stage, lens may become swollen due to continued hydration.
- This condition is called ‘intumescent cataract’.
4. Mature senile cataract (MSC):
- In this stage, opacification becomes complete, i.e whole of cortex involved.
- Lens becomes pearly white in colour.
- Such a cataract is also labeled as ‘ripe cataract’.
5. Hypermature senile cataract (HMSC):
- Occurs in any of the 2 forms:
a) Morgagnian hypermature cataract –
- Small brownish nucleus settles at the bottom, altering its position with change in the position of he head.
- Such a cataract os called Morgagnian cataract.
- Calcium deposits may also be seen on the lens capsule.
b) Sclerotic type hypermature cataract –
- The anterior capsule is wrinkled & thickened due to proliferation of anterior cells & a dense white capsular cataract may be formed in the pupillary area.
- Due to shrinkage of lens, anterior chamber becomes deep & iris becomes tremulous (iridodonesis).
B) Maturation of nuclear senile cataract
- The sclerotic process renders the lens inelastic & hard.
- The nucleus may become diffusely cloudy (greyish) or tinted (yellow to black) due to deposition of pigments.
- The commonly observed pigmented nuclear cataracts are either amber brown (cataracta brunescens) or black (cataracta nigra) & rarely reddish (cataracta rubra) in colour.
- Most common type of senile cataract is Cunieform.
- The commonest type of cataract in adults is Cortical cataract.
- Immature senile cataract can be best differentiated from mature senile cataract by Distant direct ophthalmoscopy.
- Senile cataract is painless gradual vision loss.
- Most visually handicapping cataract is Posterior subcapsular cataract.
- Highest visual morbidity is seen in Posterior subcapsular cataract.
- Steroid induced cataract is Posterior subcapsular cataract.
- Nuclear cataract is most commonly associated with ageing.
- Polychromatic Lustre is seen in Posterior cortical cataract.