Hypermetropia, ophthalmology, ak khurrana, parson disease of eye

1. Seminar – Hypermetropia
References – A K Khurana, Parson’s (ophthalmology)
Roll no. 11 ( Aditya Rana)
Batch -2018 Slbsgmch, Mandi

2. Orientation
Definition
Mechanisms
Types of hypermetropia
Symptoms
Signs
Grading
Complications
Treatment
Review question ( reference - SOCH - ophthalmology)

3. Hypermetropia/ Long Sightedness
• A refractive error in which parallel rays of light coming from infinity
are focused behind the retina with accommodation being at rest.
• In simple words, hypermetropic eye has less converging power
( <58.6D, thus light rays come to focus after a longer distance, forming
the image behind the retina.

7. Mechanisms
• Component hypermetropia-
Axial curvatural positional index
axial length of eye
1mm = 3 D
curvature of cornea
or lens
As curvature
decreases, radius of
curvature increases.
position of lens
moves posteriorly
Refractive index of
lens
decreases
microphthalmos
intraocular tumor
cornea plana
microcornea
posterior dislocation
of lens
cortical cataract
diabetes

8. • Correlation hypermetropia : due to normal biological
variations
( between parameters ) in the development of eyeball .
Functional hypermetropia : seen in internal ophthalmoplegia
paralysis of sphincter pupillae and ciliary muscle leading to
loss of accommodation and thus causing loss of near vision.

9. Types of Hypermetropia
Total
hypermetropia
Latent hypermetropia
( amount of hypermetropia usually
corrected by the inherent tone of ciliary
muscle – high in children )
Manifest
hypermetropia
Facultative hypermetropia
( amount of hypermetropia
corrected by accommodative
effort of patient )
Absolute
hypermetropia
( uncorrected
hypermetropia )

10. Symptoms
• Vary depending upon patient age and the degree of refractive error.
• Grouped under-
1. Asymptomatic .
2. Asthenopia – patient complaints of tiredness of eyes, watering, mild frontal
headache which occurs due to sustained accommodative effort for
maintaining clear near vision in hypermetropia, mild photophobia.
3. Loss of near vision.
4. Effect of ageing – patients with low hypermetropia have good vision in
young age. However, with ageing , due to decrease in accommodative
power, the hypermetropia becomes manifest and patients complain of
progressive decrease in vision . To begin with blurring occurs for near vision
and then for distant also.

11. Signs
• Size of the eyeball is normal or small.
• optics in hypermetropia.
far point is virtual
thus eyes accommodate excessively
Develop esophoria/ esotropia ( accommodative convergent squint )
( due to over accommodation, over convergence , i.e. inward
movement of eyes takes place , leading to esodeviation)

12. • Near point becomes distant – moves farther
• Angle kappa is positive – may lead to pseudoexotropia.
• Shallow anterior chamber : predisposes patient
to primary angle closure Glaucoma.
Fundus signs
• small optic disc with ill- defined margins – pseudopapillitis.
• shot silk appearance of retina.
• Recurring stye, chalazion, blepharitis may develop.
• pseudo- Fleischer’s ring may be seen.
• Movement of red reflex with the movement
of retinoscope- with motion.

15. Grading of hypermetropia
• American optometric association ( AOA) has defined three grades of
hypermetropia as below:
• Low hypermetropia, when the error is < + 2D
• Moderate hypermetropia, when the error is between + 2D to + 5D.
• High hypermetropia, when the error is > + 5D.

16. Complications
• 1. Recurrent styes, blepharitis or chalazia may occur, probably due to infection
introduced by repeated rubbing of the eyes,- often done to get relief from
fatigue and tiredness.
• 2. Accommodative convergent squint may develop in children
( usually by the age of 2- 3 years) due to excessive use of accommodation.
3. Amblyopia may develop in some cases.
Anisometric ( unilateral hypermetropia),
strabismic ( children developing accommodative squint )
Ametropic ( seen in children with uncorrected bilateral high hypermetropia)

17. • 4. predisposition to develop primary narrow angle glaucoma.
the eye in hypermetropes is small with a comparatively shallow anterior
chamber. Due to regular increase in the size of the lens with increasing
age , these eyes become prone to an attack of narrow angle glaucoma.
This point should be kept in mind while instilling mydriatics in elderly
hypermetropes.

18. Treatment
• spectacles- spherical convex lenses ( plus power ).
converging lenses – to focus light rays at the retina.
Prescribed after determining total hypermetropia through refraction
under cycloplegia ( to abolish accommodation and tone of ciliary
muscle).
In hypermetropia – all parameters decrease. ( power of eye, axial
length, curvature, index etc. )
Thus for treatment – PLUS LENSES or steepening of cornea.

20. Surgical – to achieve central steepening of cornea.
• Thermal laser keratoplasty – using thallium- holmium- chromium
(THC: YAG ) laser to correct 0.75 D to 2.5 D of hypermetropia.
• Hyperopic LASIK.
• Conductive keratoplasty (CK) : uses radiofrequency energy
( non-laser ) to shrink corneal tissue , reshaping and steepening cornea.

21. Review questions
Q . No. 1 - Shortening of 2mm of axial length of eyeball causes –
a) 3D myopia
b) 6D myopia
c ) 3D hypermetropia
d ) 6D hypermetropia
Q. no. 2 – pseudopapillitis is seen in
A) myopia
B) Hypermetropia
c) Squint
d) presbyopia

22. Q . No. – 3 the following are true about hypermetropia-
A ) the second principal focus lies in front of the retina.
B) Accommodation is used to achieve normal vision.
C) aphakia is a form of hypermetropia.
D) patients require reading glasses earlier than the normal population.
E) patients who has hypermetropic refraction following cataract surgery
will have problem for both near and distant reading.
Ans - F , T , T , T , T

23. • Q. no. – 4 The following are true about hypermetropia-
a. manifest hypermetropia is the strongest plus lens which the patient can
accept for clear distant vision.
b. latent hypermetropia is the residual and masked by ciliary tone and
involuntary accommodation.
c. latent hypermetropia can be unmasked by cycloplegic refraction.
d. Facultative hypermetropia refers to hypermetropia that can not be
overcome by accommodation.
e. Absolute hypermetropia cannot be overcome by accommodation.
Ans- T , T , T , F, T

24. Conclusion
Hyperopia is a common refractive disorder that has been
overshadowed by myopia in public perception, vision
research and the scientific literature.
The early diagnosis and treatment of significant hyperopia
and its consequences can prevent a significant amount of
visual disability in the general population.