the charactersitics of AMBLYOPIA abi.pptx

pediatrics

1. HAWASSA UNIVERSITY COLLEGE OF MEDICINE AND HEALTH SCIENCE Department of optometry Presenter: Abigiya Gebeyaw Moderator: michael.G

2. AMBLYOPIA

3. Table of content Definition Epidemiology and etiology Risk factors pathophysiology classification Clinical feature and diagnosis Differential diagnosis Complication Primary prevention and management

4. AMBLYOPIA Definition : Amblyopia is the unilateral, or rarely bilateral, decrease in best corrected visual acuity (VA) caused by form vision deprivation and/or abnormal binocular interaction, for which there is no identifiable pathology of the eye or visual pathway. Clinically it is defined as difference in best corrected visual acuity of 2 or more lines between the eyes. Amblyopia develops during childhood.

5. Epidemiology The prevalence of amblyopia worldwide is approximately 1%-5%. The world health organization (WHO) estimate 19 million children less than 15 years of age are visually impaired ; of those , 12 million are impaired due to uncorrected refractive error and amblyopia.

6. Etiology The etiology of amblyopia is associated with Uncorrected refractive error, strabismus and visual axis obstruction or combination of the above.

7. Cont.… The etiology of amblyopia can be easily remembered with the following mnemonic: SOS. S pectacle O cclusion S trabismus

8. Risk factors Positive family history Premature birth Children who have conditions that increase the risk of strabismus anisometropia or media opacity(down syndrome) Children who are developmentally delayed and were low birth weight.

9. Classification of amblyopia I. Organic . Irreversible optic nerve hypoplasia and foveal hypoplasia. n ot common now a days

10. II. Functional (potentially reversible) S trabismic amblyopia … strabismus /misaligned eye. S timulus deprivation amblyopia … media opacity A nisometropic amblyopia … high refractive error I sometropic amblyopia …….. high refractive error M eridonial amblyopia …… high refractive error

11. Pathophysiology Although many type of amblyopia exist it is believed that their basic mechanisms are the same even though each factor may contribute different amount of each specific type of amblyopia. In early postnatal development, there are critical periods of cortical development during which neural circuits display a heightened sensitivity to environmental stimuli and are dependent on natural sensory experience for proper formation.

12. Cont … During these periods, the developing visual system is vulnerable to abnormal input due to visual deprivation, strabismus, or significant blur resulting from anisometropia or isometropia . Conversely, the visual system’s plasticity early in development allows the greatest opportunity for amblyopia reversal.

13. Cont … Amblyopic vision deficits result primarily from visual cortical changes. With abnormal visual experience early in life, cells of the primary visual cortex can lose their ability to respond to stimulation of 1 or both eyes.

14. Diagnosis Amblyopia should be considered as a possible diagnosis in children with asymmetric visual behavior or acuity. Diagnosis of the condition early is important, preferably before the age of 6.

15. History Elicit any previous history of pathcing or eye drops as well as past compliance with these therapies.elict any previous history of glasses wear , prematurity and an eye misallignment . Document previous ocular surgery or disease The history taking process should include any family history of vision problem specifically amblyopia and strabismus.

16. Physical examination Visual acuity Crowding phenomenon Neutral density filter Contrast sensitivity Binocular function Cycloplegic refraction funduscopic examination; perform a full eye examination to rule out ocular pathology Color vision stereopsis

17. S ymptoms Patients with unilateral amblyopia are often asymptomatic. Occasionally patients will complain that one eye is blurry or younger children may report discomfort in the affected eye. Poor depth perception or clumsiness may be noted

18. Signs Deprivational amblyopa could manifest with ptosis an eyelid hemangioma or a cataract. Strabismic amblyopia may show commonly constant ocular deviation. Esotropia causes more amblyopia as compared to exotropia .

19. Cont …. On clinical examination unilateral amblyopia will show assymetric visual behavior or acuity testing result. Severe cases may have a mild afferent pupillary defect. Anisometropic amblyopia often shows no obvious sign when observing the patient but the cycloplegic retinoscopy will reveal the anisometropia .

20. Cont ….. Three diagnostic approaches : A difference between best corrected acuity of the two eyes of two lines or more. Acuity in the amblyopic eye of less than 6/9. T he Patient should show no sign of pathology that might account for the reduced vision .

21. Differential diagnosis Ocular pathology Refractive error Prechiasmal lesion Optic nerve insult Congenital ptosis

22. Management The general idea of the management is to first treat the underlying cause for the amblyopia . Example of this treatment would include prescribing glass for anisometropia strabismus surgery or spectacle or removal of unilateral cataract to eliminate the media opacity.

23. General treatment The key to optimal treatment of amblyopia is early detection and preventation . Treatment involves the following steps : 1 . Eliminate (if needed) any obstruction of the visual axis , such as a cataract . 2 . Correct any significant refractive error. 3 . Promote use of the amblyopic eye.

24. Cont … In asymetric case or unilateral cases active treatment with pathcing , pharmacologic agent or surgery can often improve. In symmeric bilateral cases treatment consists of addrresing the etiologies of the diminished vision often there is residual bilateral amblyopia which may improve over time.

25. Treatment options Treatment of amblyopia involves Correction of refractive error Occlusion theraphy Penalization Drug theraphy Surgery to treat the cause of amblyopia.

26. Correction of refractive error Spectacle correction alone is often the first line of theraphy for amblyopia. Although the time course of improvement is variable, studies have demonestrated that patients with isometropic , anisometropic and strabismic amblyopia show significant improvement with glasses alone. But when glasses alone do not treat amblyopia fully, patching and atropine penalization are considered.

27. Occlusion therapy (patching) The following are general guidelines for occlusion therapy Patching may be full time or half time. Always consider lack of compliance in a child when visual acuity is not improving . In addition to adhesive band aid type patches consider the use of opaque contact lens , occluders mounted on spectacles and adhesive tape on glasses.

28. Patching of the sound eye to improve the acuity of the amblyopic eye is the most commonly used technique to treat amblyopia

29. Duration of occlusion should be until the visual acuity develops fully, or there is no further improvement of vision for 3 months.

30. Atropine penalization therapy The following are general guidelines for atropine penalization therapy: Atropine eye drops are placed in the sound eye Establish whether the vision of the better eye has been degraded sufficiently with the chosen therapy.

31. Pharmacologic penalization of the sound eye is another commonly used modality to treat amblyopia.

32. Cont … Atropine is the most commonly used pharmacologic agent Dosing can be a drop in the sound eye daily or on weekends only. These drops weaken the focusing mechanism of the eye so reducing the close up vision to such an extent that the child’s brain chooses the image form the amblyopic eye rather than the blurred image from the stronger eye.

33. Optical penalization. involves the prescription of excessive plus lenses (fogging) or diffusing filters for the sound eye. This form of treatment avoids potential pharmacologic adverse effects and may be able to induce greater blur than cycloplegic agents.

34. surgery Amblyopia itself is not a surgical condition but there are times when surgery may treat the underlying cause of the amblyopia . Refractive surgery may be used to correct anisometropia Eye muscle surgery can correct strabismus. Cataract, ptosis vitrectomy or corneal surgery may alleviate causes of deprivation.

35. Complication The main complication of not treating amblyopia is long term irreversible vision loss . Most cases of amblyopia are reversible if detected and treated early so this vision loss is preventable.

36. F ollow up Follow up during treatment is typically somewhere between every 1 up to 3 months. when treatment is discontinued, follow up is necessary to ensure there is no regression of effect.

37. Prognosis Younger the age better the prognosis. Most textbooks do not recommend trying amblyopia theraphy in the second decade of life but some improvement can be obtained in few cases.

38. Cont … If there is no improvement or prognosis despite good compliance and treatment suspect an alternate diagnosis such as optic nerve hypoplesia , subtle macular abnormalities or other anterior visual pathway disorder.

39. R eference The pediatric eye disease investigator group. Randomizes trial of treatment of amblyopia. 2022-2023 edition, Pediatric ophthalmology BCSC. American acadamy of opthalmology . Comprehensive opthalmology 6 th edition.

40. THANKS !