Aniridia and low vision

Aniridia and low vision

1. Aniridia and low vision Presented by :Rashad Ibn Muhammed M.optom 1 st sem

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 Some researchers consider Aniridia a subtype of coloboma 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.

10. signs Photophobia Nystagmus (Pendular) Strabismus (Esotropia)

11. cornea Corneal vascularisation Epithelial ulcers Aniridic keratopathy Arcus juvenilis Microcornea

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.

14. Crystalline lens Transparent or opaque Ectopia lentis Subluxated or Dislocated lens 

15. Fundus Foveal hypoplasia Optic nerve hypoplasia Macular hypopigmentation Macular reflex dull Glaucomatous cupping

16. Associated syndromes Miller syndrome WAGR Syndrome Gillespie Syndrome

17. 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.

18. WAGR Syndrome W : Wilms’ Tumour A : Aniridia G : Genitourinary problems R : (Mental) Retardation

19. 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.

20. 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.

21. 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

22. 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.

23. Medical treatment  Prophylaxis for the prevention of glaucoma Miotics Beta-blockers Sympathomimetics Carbonic anhydrase inhibitors Prostaglandin analogues

24. Surgical treatment  Penetrating keratoplasty (PK)  Cataract extraction Trabeculectomy Goniotomy

25. Low vision management Visual acuity Measure VA by using TAC (Teller acuity chart) (1m to 3yr) Lea symbols (1-3 yrs) Bailey and Lovie charts

26. management Provide magnification for distance visual tasks Provide magnification for near visual tasks Provide light filtration Provide contrast enhancement

27. 1.HAND HELD TELESCOPES

28. 2.SPECTACLE MOUNTED TELESCOPES

29. 3.MaxTV Or Seetv spectacle binoculars

30. 4.Bioptic Telescope

31. For Near 1.Hand magnifirs

32. 2.Stand magnifiers

33. 3. SPECTACLE MAGNIFIERS

34. 6.CLOSED CIRCUIT TELEVISION READING SYSTEMS (CCTV)

35. 7.PORTABLE CCTV

36. ABSORPTIVE LENSES “SUNLENSES”

37. REDUCED APERTURE CONTACT LENSES

38. Non optical devices

39. READING STANDS

40. 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

41. Thank you