Retinoscopy

By Dr.Prakriti Yagnam

1. retinoscopy DR.K.PRAKRITI YAGNAM

2. RETINOSCOPY: - Objective method to find error of refraction - Introduced by BOWMANN Also called skiascopy/shadow test/ pupilloscopy /korescopy PRINCIPLE: - Neutralization - When light is reflected from mirror into eye the direction in which light travels across pupils depends on its refractive state

3. OPTICS: Area of fundus illuminated ILLUMINATION STAGE Image at far point Reflected light illuminate pupillary area REFLEX STAGE Observed by doctor PROJECTION STAGE

4. ILLUMINATION STAGE: Original source of light - S Immediate source of light – S With plane mirror – immediate source moves against move ment of mirror - With concave mirror- with movement

5. REFLEX STAGE: - With plane mirror image at fovea moves against to immediate source of light PROJECTION STAGE: At a distance of 2/3m. Equivalent to 1.5D - Distance between doctor and patient-1m.

6. PREREQUISITES: Dark room – 6m Trial set- Spherical lens – 0.25 to 4.00 (0.25 rise) 4.25 to 6.00(0.5 rise) 7.00 to 14.00(1.0 rise) 16.00 to 20.00(2D rise) Cylindrical lens – 0.25to 2.00(0.25 rise) 2.5 to 6.00(0.50 rise) Prisms and accessory sets Trial frame , distance and near vision charts , retinoscope

7. TYPES OF RETINOSCOPY: Reflecting(mirror) Self illuminated retinoscopy Plane plane+concave spot streak (Priestley-Smith) retinoscopy more sensitive for astigmatis m

8. PLANE AND CONCAVE MIRROR EFFECT: Sleeve up – concave mirror effect – hazy media and high ametropia Sleeve down – plane mirror effect – for routine retinoscopy

9. PROCEDURE: Working distance – 2/3m. In cases of non cycloplegic & non presbyopic &myopic eye fogging done to reduce accommodation In young patients and hypermetropia- cycloplegia done wet retinoscopy - If cycloplegia not done – dry retinoscopy

10. When cycloplegics used dioptric power must be reduced Atropine – 1D Homatropine – 0.5D Cyclopentolate – 0.75D

11. MOVEMENTS OF RED REFLEX: emmetropia hypermetropia with movement myopia < 1D myopia > 1D - against movement myopia = 1D - no movement

12. NEUTRALISATION OF RED REFLEX: Spherical/with the rule/against the rule astigmatism neutralized either in horizontal or vertical meridians Oblique or irregular astigmatism axis identified first and corrected

13. Low refractive error – Reflex bright and fast High refractive error – Dull and slow

14. POWER CORRECTION: - Sphere + Cylinder - Two spheres - Two cylinders

15. END POINT: - Over correction by 0.25D – reversal of movement must be seen decreases – with movement seen -Working distance increases – against movement seen

16. STREAK RETINOSCOPY: Correct axis-Streak narrow and brightest If not- Wide streak and less intensity - Break in alignment b/w reflex in pupil and band outside - skew observed

17. CONFIRMATION OF AXIS: STRADDLING

18. Static retinoscopy: without active use of accommodation Dynamic retinoscopy: with active use of accommodation that is for near vision

19. FORMULA: Ref error = Retinoscopic findings – distance – cycloplegic deduction tone

20. PROBLEMS: - Red reflex may not be visible/poor -Abnormal active accommodation – cleared – fogging cycloplegics -Scissoring shadows due to mixed aberration – less in Undilated pupil Spherical aberrations – Brightness diff at center and periphery Conflicting shadow in irregular astigmatism Triangular shadow in conical cornea

21. THANK YOU!!!