Amblyopia

amblyopia also known as the lazy eye
often goes unnoticed.

1. AMBLYOPIA BY: Dr NIKITA JAISWAL Ims & sum hospital

2. Glossary: Introduction Pathophysiology Classification Management

3. INTRODUCTION Amblyopia : ( greek word means blunt eye) Also called as: lazy eye is a disorder of sight. Results in decreased vision in an eye that otherwise appears normal.

4. DEFINITION: As binocular or uniocular decrease in {BCVA} due to pattern visual deprivation or binocular interaction during visual immaturity for which there is no obvious ocular pathology or visual pathway defect

5. pathophysiology Deprivation of form vision:

6. Abnormal binocular interactions: when incompatible images are formed on the fovea of both the eyes involvded in ALL TYPES OF U/L AMBLYOPIA & NOT IN B/L SYMMETRICAL AMBLYOPIA.

7. Characteristics: Single letter acuity is better than linear acuity seen in strabismic amblyopia Phenomenon of crowding Because of abnormal contour interaction Abnormal eye movement Contrast sensitivity : In stabismic amblyopia it improves on decreased illumination.

8. characteristics strabismic anisometric Angular VA better than linear VA ++++ ++ Contrast better on dec . illuminance + - Better performance in mesopic conditions ++ +++ Vernier acuity less affected than resolution acuity ++++ _ Naso temporal OKN asymmetry +++ _ VEP abnormalities ++ ++

9. CLASSIFIED AS: Strabismic amblyopia Anisometric amblyopia Form vision deprivation

10. STRABISMIC AMBLYOPIA Most common form of amblyopia. Strabismic amblyopia develops in the deviating eye. Constant,non alternating,heterotropias are the type most likely to cause significant amblyopia. It is thought to result from compeititive or inhibitory interaction between neurons carrying non fusible input from 2 eyes.

11. ANISOMETRIC AMBLYOPIA Dissimilar refractive errors in the 2 eyes cause the image on 1 retina to b echronically defocused. More prevalent than strabismic amblyopia. Levels of anisometropia >1.50D of anisohyperopia 2.00D of anisoastigmatism 3.00D of anisomyopia

12. ISOAMETROPIC AMBLYOPIA B/L dec. in VA results from large,approx . equal, uncorrected ref errors. Hyperopia exceeding 4.00-5.00D. Myopia exceeding 5.00-6.00D.

13. MERIDONIAL AMBLYOPIA Uncorrected B/L astigmatism in early childhood may result in loss of resolving ability limited to the chronically blurred meridians . The degree of cylinder is unknown Most ophthalmologists recommend correction when there is > 2.00-3.00 D of cylinder.

14. DEPRIVED FORM OF VISION DEPRIVATIONAL AMBLYOPIA

15. EXAMINATION VISUAL ACUITY FIXATION FIXATION PATTERN ASSESSSMENT OF STRABISMUS ASSESSMENT OF BINOCULARITY

16. PRINCIPLE FOR MANAGEMENT: EARLY DETECTION: + nce of nystagmus , roving movement,abnormal head posture Asymmetrical fundal glow ( bruckner’s reflex) Observation of delayed visual milestones. Correction of refractive errors : Removal of any media opacities. Providing the worse eye a compeititive advantage over the better eye by occluding the better eye. Strict vigilance & monitoring of therapy.

17. Results of monocular vision in 3-7 yrs with mod.amblyopia . Occlusion in moderate amblyopia in children bet 3-7 yrs At 5 wks improvement of 2.2 lines,improvement directly related to no of hours of patching(lesser baseline VA) At 6 months, improvement of 3.1 lines irrespective of hours of patching in pts with baseline VA between 20/40 & 20/100

18. OCCLUSION/PENALIZATION (3-7 YRS) Occlusion vs. Atropine penalization for 6 months in children betw 3-7 yrs Similar improvement of VA in both groups of about 3.7 lines after 2 yrs starting of therapy. After 2 yrs the amblyopic eye VA remained about 2 lines worse than the VA in the sound eye in both the groups

19. 6 hours/2 hours 2 hrs & 6 hrs occlusion in moderate amblyopia in 3-7 yrs Similar improvement of VA in both groups 2 hrs + 1 hr near work equal a 6 hrs occular regimen

20. Near/non near GREATER IMPROVEMENT IN VA IN CHILDREN WITH SEVERE AMBLYOPIA WHO PERFORMED NEAR ACTIVITIES ALONG WITH PATCHING. NEAR & NON NEAR ACTIVITIES WITH 2 HOURS PATCHING IN 3-7 YEARS

21. Occlusion therapy/spectacles Evaluation of 2 hours of patching with near vision activities vs. Spectacles alone for strabismic & anisometropic amblopia in 3-7 yrs. Significant difference between the improvement in VA in the 2 groups at 5 wks. After a period of refractive adaptation,2 hrs of daily patching with 1 hr of near visual activities improves VA in mod to severe amblyopia

22. Evaluation of spectacles alone as T/T for anisometropic amblyopia in children between 3 & 7 years 33-50% pts showed resolution of amblyopia : rest required occlusion after 2 months. (plateau with spectacles alone)

23. EVALUATION OF amblyopia between 7-17 yrs Optical correction suffices in 25 % cases Children bet.7 & 12 yrs improved with patching irrespective of previous t/t for amblyopia . Pts betwn 13& 17 yrs improved with patching only if there was no h/0 of previous T/T Results of long term sustenance of the improvement of VA in older amblopes require further studies.

24. MANAGEMENT: OCCLUSION PENALIZATION PLEOPTICS CAM STIMULATOR RED FILTERS DRUGS

25. OCCLUSION: mainstay of the t/t... Patch over the skin>patch of the spectacles. A competitive advantage is given to the worse eye over the better eye. Total/partial Full time/part time

26. TOTAL OCCLUSION: Direct patch of the skin Patch over the back surface of spectacles Doyne’s occluder Pirate patches Occlusive contact lens

27. DOYNE OCCLUDER

28. Partial occlusion: Refers to partial exclusion of light & form perception. Refractive correction of the glasses that is being dispensed should be accurate. The glasses should be worn properly.

29. PENALIZATION: selective fogging Selective fogging of the better eye by means of glasses/ cycloplegics . Pharmological penalization i s more acceptable cosmetically. It can be for distance or near penalization Dist: good eye for near & the amblyopic eye for dist Total: fogging for near as well as distance.

30. PLEOPTICS: indicated in patients with eccentric fixation Principle: establish foveal superiority over the retinal periphery & to bleach out the ecccentric point of fixation. Fovea is re-educated to assume the straight head position. Time taking procedure Age : more than 5 yrs children who are intelligent & coopoerative . Not more than 7 yrs

31. CAM STIMULATOR Principle: visual area of brain respond to a stimuli of a particular spatial frequency & can be stimulated to evoke visual function in amblyopic eye. Contains: 7 rotating light & dark coloured disc which have diff width Rotated for 7 mins at the rate of 1rotatn/min It is of historical use

32. Red filters Principle: rod domoninated area is used for eccentric fixation. Red filter is use to motivate the patient to use fovea.

33. P rognosis Younger the child better the prognosis. Deprivation amb . Carries poor prognosis. Strabismic amblyopia has best prog . Presence of eccentric fixation worsens the prog . Occlusion is the better tha other methods.

34. THANK YOU