Hypermetropia meaning, definition, causes, symptoms and treatment

Medico Feeds October 29, 2020

Hypermetropia:

Meaning:

It is a condition, in which a person can't see near objects clearly.

Definition:

Hypermetropia (Hypermetropia) or long-sightedness is the refractive state,where the parallel rays of light from infinity are focused posterior to the retina with accommodation being at rest.


Etiological types:

1. Axial: 
Most common form. Due to reduced anteroposterior diameter of the eye.
2. Curvatural:
Due to changes in curvature of the cornea,lens or both.
3. Index:
Due to decreased refractive index of the lens.
4. Positional:
Due to displacement of lens.
5.others: aphakia.

Clinical Types:

1.Physiological Hypermetropia:
It results from normal physiological changes during the development of eye and it the commonest type. 

2. Non- Physiological Hypermetropia:
a) Congenital: 
    seen in,
  - Microphthalmos
  - Nanophthalmos
  - Microcornea
  - Aphakia 
  - Subluxation of lens
b) Acquired:
    includes,
  - Senile (old age)
  - positional
  - axial
  - curvatural
  - psuedophakic Hypermetropia

3.Functional:
Results from paralysis of accommodation.

Age factors:

Children are hypermetropic upto the age of 5-7 years. There is an tendency to develop long-sightedness after the age of 50 years.

Clinical features:

Symptoms:

1.Asymptomatic:
 When the error is small, usually corrected by mild accomodation.
2. Asthenopic symptoms:
  - tiredness of eyes
  - photophobia
  - frontotemporal headache
  - watering
3. Defective vision with asthenopic symptoms
4. Defective vision only:
   When hypermetropia is high, can't corrected by voluntary accomotative efforts.

Signs:

1. Smaller cornea
2. Eyeball appears small
3. Shallow anterior chamber
4. Fundus examination shows small optic disc with ill defined margins.
5. A scan shows shortened anteroposterior length of the eye.

Grading of Hypermetropia:

              Low       -      ≤+2D
       Moderate    -      +2D   to  +5D
             High       -       ≥ +5D

Complications:

1. Recurrent styles
2. Blepharitis
3. Chalazion
4. Accomodative convergent squint
5. Amblyopia
6. Glucoma

Treatment:

1. Optical treatment:
  To bought the light to focus on the retina Convex lenses are used. It may be,
     -  spectacles
     -  contact lenses
2. Surgical treatment:
   -  thermal laser keratoplasty
   - hyperopic PRK
   - hyperopic LASIK
   - conductive keratoplasty (CK).