Anisometropia

It tells about Anisometropia

1. ANISOMETROPIA SALAL MOHAMMAD B.OPTOM 2 ND YEAR

2. iNDEX INTRODUCTION ETIOLOGY CLINICAL TYPES SYMPTOMS DIAGNOSIS TREATMENT

3. iNTRODUCTION When the total refraction of the two eyes is unequal, the condition is called ANISOMETROPIA. The optical state with equal refraction in the two eyes is termed ISOMETROPIA. Small degree of anisometropia is of common occurrence and of not much concern. A difference of 1D in two eyes causes a 2% difference in the size of the two retinal images.

4. A difference up to 5% in retinal images of the two eyes is well tolerated. A difference between 2.5 and 4.0 D can be tolerated depending upon the individual sensitivity. If the difference more than 4 D not tolerated and is a matter concern.

5. ETiOLOGY CONGENITAL and DEVLOPMENTAL ANISOMETROPIA occurs due to differential growth of the two eyeballs. ACQUIRED ANISOMETROPIA – a) Uniocularaphakia after removal of Cataractous lens. b) Implantation of IOL of wrong power. c) Trauma to the eye d) Keratoplasty in one eye e) Asymmetric age changes.

6. CLiNiCAL TYPES Simple anisometropia Compound anisometropia Mixed anisometropia Simple astigmatism anisometropia Compound astigmatism anisometropia Fixed astigmatism anisometropia

7. 1- S imple anisometropia In this case, one eye is normal (emmetropic) and the other eye is either myopic ( simple myopic anisometropia) or hypermetropic (simple hypermetropic anisometropia) Normal eye Myopic eye Hypermetropic eye 7

8. 2- Compound anisometropia I n this case, both eyes are either hypermetropic (compound hypermetropic anisometropia) or myopic (compound myopic anisometropia), but one eye is having higher refractive error than the other Myopic eye Myopic eye 8

9. 3- Mixed Anisometropia In this case, one eye is myopic and the other is Hypermetropia. This is also Antimetropia Myopic eye H yperopic eye 9

10. 4- Simple astigmatism anisometropia When one eye is normal and the other has either simple myopic or hypermetropic astigmatism Normal eye Simple myopic astigmatism 10

11. 5- Compound astigmatic anisometropia When both eyes are astigmatic but of equal degree Simple myopic astigmatic Simple myopic astigmatic 11

12. 6- Mixed astigmatic anisometropia In this case, one eye has hypermetropic astigmatism and the other has myopic astigmatism. Simple myopic astigmatic Simple hyperopic astigmatic 12

13. S tatus of binocular vision in Anisometropia Three possibilities exist as follows: Binocular single vision is present in small degree of anisometropia (<3 D) Uniocular vision. When refractive error in one eye is high degree. Alternate vision occurs when one eye is emmetropic or moderately hypermetropic and the other myopic, then hypermetropic eye is used for distant vision and myopic for near. 13

14. Eye strain Headache Disturbance of binocular vision Suppression of one eye Difficulty in fixation Diplopia occur if the difference exceeds 5% SYMPTOMS 14

15. DiAGNOSIS 1- Retinoscopic examination. 2- testing for state of binocular vision- a ) F riend test b) worth’s four-dot test

16. FRIEND TEST- 1- F, I, N are written in green and R,E,D IN RED COLOR. 2- It is in corporated in Snellen’s vision box. 3- the patient is to sit a distance of 6 m after wearing diplopia goggles with red glass in front of right eye and green in front of the left eye and asked to read the latters. F R I E N D 16

17. Results are interpreted as – 1- Binocular single vision- patient will read F R I E N D at once. 2- Uniocular single vision- patient will read either F I N or R E D. 3- Alternate vision- the patient will read F I N at one time and R E D at other time. F R I E N D Binocular single vision R E D or F I N Uniocular vision 17

18. WORTH’s FOUR-DOT TEST- 1- For this test, the patient wear goggles with red lens in front of the right eye and green lens in left eye and views a with four lights: one RED, two GREEN, one WHITE. 2- the patient is made to sit at a distance of 6 m. 18

19. Interpretation is as below- 1- Normal binocular single vision- if the patient sees all the four lights in the absence of manifest squint. 2- In abnormal retinal correspondence, the patient see four light even in the presence of manifest squint. 3- If the patient sees only two red lights, it indicates LEFT SUPRESSION. 4- If the patient sees only three green light, indicate RIGHT SUPRESSION 5- When patient sees the three green lights and two red lights, alternately, it indicates presence of ALTERNATE SUPRESSION 6- If the patient sees the five lights (two red and three green), indicate DIPLOPIA LEFT SUPRESSION DIPLOPIA RIGHT SUPRESSION 18 9

20. TREATMENT- 1- GLASS : the corrective spectacles can be tolerated up to a maximum difference of 4 D, after that, there occurs diplopia. 2- CONTACT LENSES are advised for higher degrees of anisometropia. 3- ANISOMETROPIC SPECTACLES are an alternate modality for treatment of anisometropia. 4- OTHER MODALITIES OF TREATMENT - a) IOL implantation for Uniocular aphakia. B) Refractive corneal surgery for unilateral myopia , astigmatism and Hypermetropia. C) P hakic refractive lenses are good option for refractive error of 4-10 D. 20

21. Thank You! Salal mohammad