2. OBJECTIVES
To know about Aniridia, as its signs and symptoms
To aware about the management of low vision
patients with Aniridia
3. DEFINITION
Aniridia is a congenital, hereditary, bilateral,
extreme form of iris hypoplasia or absence of iris
4. Aniridia is not just an defect in iris development but is
a panocular disorder with
Macular hypoplasia,
Optic nerve hypoplasia,
Cataract
Corneal changes
Nystagmus.
5. How ever, a small stump of iris tissue exists at iris
root
6. TYPES
Aniridia Type 1 (AN-1)
Is inherited through the autosomal dominant
inheritance (AD) pattern
Only affects the eye not the rest of the body.
Caused by mutation in the PAX6 gene on
chromosome 11p13
7. Aniridia Type 2 (AN-2)
Is sporadic, that means it is not inherited from either
parent
Children who have sporadic congenital Aniridia may
only have Aniridia or they may also have a chance
of having problems with other parts of their bodies.
Children with (AN)-2 are at risk of developing one of
two associated conditions, Miller Syndrome or
WAGR Syndrome
8. Aniridia Type 3 (AN-3)
Can be associated with Gillespie Syndrome
(AN)-3 follows the autosomal recessive (AR)
inheritance pattern.
9. PATHOGENESIS
1. Some researchers consider Aniridia a subtype of
coloboma
2. In the ectodermal theory Aniridia is caused by
failure in the optic vesicle rim development
between the 12th and 14th weeks of gestation
Supporting this theory is the association of aniridia with
other ectodermal defects: anomalies in the retina,
absence of the fovea, and absence of iris musculature.
12. IRIS
Complete absence of iris on oblique illumination
Hypoplasia with irregular pupillary margins (atypical
coloboma of pupil)
Root of the iris visible on gonioscopy
13. Angle of the anterior chamber
Trabecular meshwork may be partially or completely
covered by the iris stump.
18. MILLER SYNDROME
It is a condition that is also known as the Genee-
Wiedemann syndrome, Wildervanck-Smith
syndrome or postaxial acrofacial dystosis
(POADS)
It causes problems with the development of the
face and the arms and legs such as cleft palate and
small jaw.
20. W: WILMS’ TUMOUR
Also called as nephroblastoma
A childhood tumour of the kidney. Children with AN-
2 have a 30% risk of developing Wilms’ tumour
before the age of 5 years old.
If detected early Wilms’ tumour can be treated
successfully.
21. GILLESPIE SYNDROME
This is a rare, genetic condition which can cause
Aniridia and cerebella ataxia.
Cerebella ataxia affects the parts of the brain
responsible for co-ordination, balance and muscle
tone.
Cerebella ataxia can cause problems with walking
unaided, writing and clear speech.
22. TREATMENT
Correction of refractive errors and treatment of
amblyopia are simple and essential measures.
Optical low vision aids for those with significant
visual impairment and help with schooling and
social support should be provided.
Tinted or photo chromic lenses can be used to
reduce light sensitivity associated with the large
papillary aperture.
Medical treatment
Surgical treatment
23. TREATMENT OF AMBLYOPIA AND STRABISMUS
Usually the potential visual acuity in both eyes
should be symmetrical.
When the vision is unequal without structural
difference, vigorous amblyopia exercises should be
performed in the worst eye.
Binocularity can be achieved if macular hypoplasia
is not severe.
Strabismus surgery is indicated at an early age.
24. MEDICAL TREATMENT
Prophylaxis for the prevention of glaucoma
Miotics
Beta-blockers
Sympathomimetics
Carbonic anhydrase inhibitors
Prostaglandin analogues
26. LOW VISION MANAGEMENT
Visual acuity
Measure VA by using
1. TAC (Teller acuity chart) (1m to 3yr)
2. Lea symbols (1-3 yrs)
3. Bailey and Lovie charts
27. MANAGEMENT
Provide magnification for distance visual tasks
Provide magnification for near visual tasks
Provide light filtration
Provide contrast enhancement
41. REFERENCES
Essentials of low vision:Richard L Brilliant
Low vision rehabilitation of children with
Aniridia By Sarah Appel, O.D. (William Feinbloom
Vision Rehabilitation Center)
http://emedicine.medscape.com/article/1208379
http://eyewiki.aao.org/Aniridia
https://www.rnib.org.uk/eye-health-eye-conditions-
z-eye-conditions/aniridia