Retinoscopy

Optics, refraction & retinoscopy

1. RETINOSCOPY Presenter : Dr. Aakanksha Bele Guided by : Dr. Pradeep Sune Sir

2. Introduction Also known as sciascopy or shadow test or pupilloscopy or korescopy . Started by Sir William Bownman in 1859. Term retinoscopy was coined by Parent in 1881. Definition – Objective method of finding out the error of refraction by utilizing the technique of neutralization.

3. Evolution of Retinoscope 1859 – Sir William Bowman – introduced retinoscopy, he saw peculiar linear reflex while viewing astigmatic eyes with Helmholtz’s new ophthalmoscope. 1873- Ferdinand Cuignet ( father of retinoscopy) – first described retinoscope and the objective diagnosis of refractive errors. 1901 – Wolff introduced first electric retinoscope. 1902 – A.J. Cross introduced dynamic retinoscopy. 1903 – Duane – advocated use of cylindrical lenses in astigmatism. 1927 – Copeland (father of streak retinoscopy) – introduced streak retinoscope.

4. Why to do Retinoscopy? To estimate a person’s refractive error before starting subjective refraction. To estimate refractive errors of people who have problems communicating: Babies or young children. People with physical or mental disability. People who speak language that is difficult to. Understand. Deaf or mute people.

5. How does the retinoscopy work? The retinoscope illuminates the inside of the patient’s eye. The clinician examines the light as it is reflected from the external limiting membrane of the patients retina.

6. Optics Focault’s Principle :- When light is reflected from a mirror into the eye, the direction in which the light will travel across the pupil will depend upon the refractive state of the eye. 3 stages : Illumination stage – illumination of subjects retina Reflex stage – the reflex imagery of this illuminated area formed by the subject’s dioptric apparatus Projection stage – projection of image by the observer

7. Optics of Retinoscope Projection System : Light source Condensing lens Mirror Focusing sleeve Current source Observation System : for examiner to see the retinal reflex from the far point.

8. Optics of emmetropia, hypermetropia and myopia

9. With movement

10. Against movement

11. The Goal

12. Types of Retinoscopy Static vs Dynamic Retinoscopy Wet vs Dry Retinoscopy

13. Static Retinoscopy Definition - patient fixates on a distance target with accommodation relaxed. Shine the streak of light into patient’s eye and move it within the pupil. Observe how the streak appears to move in the patient’s pupil which tells us where the far point of his eye is located.

14. Dynamic Retinoscopy Definition - Patient fixates on a near target and the status of his/ her accommodation is evaluated Refraction with active accommodation

15. Near Retinoscopy The patient is looking at a near object, with accommodation at rest.

16. Types of Dynamic Retinoscopy Monocular estimation method – helps to calculate patients lag or lead of accommodation. Bell retinoscopy – retinoscope remains in a fixed position & target is moved. Nott’s retinoscopy – determines lag/ lead of accommodation by moving retinoscopic aperture towards or away from the eye Book retinoscopy – aka getman retinoscopy. Developed to obtain information about the visual processing of nonverbal infants Cross retinoscopy Sheard’s retinoscopy Tait’s retinoscopy Mohindra retinoscopy – also known as near monocular retinoscopy. For determining the refractive state of infants & children.

17. Dry Retinoscopy Without Cycloplegics

18. Wet Retinoscopy With the use of cycloplegics. Indications : Accommodative fluctuations indicated by a fluctuating pupil size and/or reflex during retinoscopy Patients with esotropia or convergence excess esophoria Disadvantages : Temporary symptoms of blurred vision & photophobia Adverse effects & allergic reactions

19. Salient features of common cycloplegic & mydriatic drugs Sr.no Drug Age of patient when indicated Dosage Peak effect Time for retinoscopy Duration of action Period of post cycloplegic test Tonus allowance 1 Atropine sulphate (1% oint ) < 5 years TDS X 3 days 2-3 days 4 th day 10-20 days After 3 wks of retinoscopy 1 D 2 Homatropine hydrobromide (2% drops) 5 - 8 years One drop every 10 min for 6 times 60-90 mins After 90 min of instillation of first drop 48 – 72 hrs After 3 days of retinoscopy 0.5 D 3 Cyclopentolate hydrochloride (1% drops) 8 – 20 years 1 drop every 15 min for 3 times 80– 90 mins After 90 min of instillation of first drop 6 – 18 hrs After 3 days of retinoscopy 0.75 D 4 Tropicamide (0.5%, 1%) Used only as mydriatic 1 drop every 15 min for 3- 4 times 20 – 40 mins 4 – 6 hrs 5 Phenylephrine (5%, 10%) Used only as mydriatic 1 drop every 15 min for 3- 4 times 30 – 40 mins 4 – 6 hrs

20. Far point Definition – Point in space that is conjugate to the fovea, when accommodation is at rest Myopes – Far point is between clinician & patient Hyperopes – Far point is behind the patient Astigmatism – Have 2 far points Emmetropes – Far point is at infinity.

21. Working Distance How far are we from our patient…. The working distance typically used when performing retinoscopy is 67cm (26”). This created working distance lens of 1.50D Short arms ??? 50 cms (20”) 2.00D working distance lens

22. Assessing the reflex Reflex Observation Refractive Error Width Narrow Large Wide Small Brilliance Dull Large Bright Small Speed Slow moving Large Fast moving Small Direction With Hyperopia Against Myopia

23. Types of Retinoscope Self illuminated retinoscope:- Spot retinoscope – have an ordinary light globe that gives a “patch” or “spot” of light Streak retinoscope – have a special globe that gives a line, or “streak”, of light

24. Parts of streak retinoscope

25. Types of Retinoscope Reflecting mirror retinoscope Plane mirror Priestley – smith’s mirror (plane and concave mirrors)

26. Loose lenses or Phoropter?? For young patients who cannot sit at phoropter, trial lenses may be used Phoropter can be used after age of 5 yrs

27. The retinoscope: Sleeve up or Sleeve down It is important to use the sleeve position which produces a divergent light. Streak retinoscope bulb has linear filament. Move sleeve up or down to produce divergent light.

28. Procedure Patient is made to sit at a working distance of 2/3 rd m from the examiner. The room should have dim light Hold the retinoscope in your right hand & right eye for patient’s right eye (swap for left eye). Ask the patient to focus on a far point. Turn the retinoscope on & rotate the collar so the light is vertical Shine the light into patient’s right eye & observe the red reflex. Now move the light from side to side 3 or 4 times. Observe, Neutralize & Interpret.

29. Procedure cont.. For non cycloplegic refraction of patient who are not presbyopia it is necessary to fog the fellow eye. Occlusion is required in : When eye being tested is densely amblyopic Patient objects to fogging due to diplopia or asthenopia Unable to estimate acuity & provide adequate fog lens. For cycloplegic refraction there is no need to fog, since accommodative component is removed by cycloplegia

30. “You can’t learn retinoscopy by reading a book” - Jack C. Copeland

31. Lets do some Retinoscopy

32. 3 steps to retinoscopy

33. 1. Basics (working with only spherical lens)

34. Prescription +3.00 D sphere -1.50 D (subtract working distance) +1.50D (final prescription)

35. 2. Again Sphere

36. Prescription +2.00 D sphere -1.50 D (subtract working distance) +0.50D (final prescription)

37. 3. One more

38. Prescription +1.00 D sphere -1.50 D (subtract working distance) -0.50D (final prescription)

39. 4. Lets start with against the motion

40. Prescription -1.00 D sphere -1.50 D (subtract working distance) -2.50D (final prescription)

41. That easy??? No !!! Lets solve some with Astigmatism…

42. 5. Simple Astigmatism

43. Prescription +2.00 D sphere +1.00D cylindrical at 90 -1.50 D (subtract working distance) +0.50 +1.00 at 90 (final prescription)

44. 6. Another simple one

45. Prescription +3.00 +2.00 at 180 -1.50 D (subtract working distance) +1.50 +2.00 at 180 (final prescription)

46. 7. What if we get against the motion at the beginning ??

47. Prescription -3.00 +2.00 at 90 -1.50 D (subtract working distance) -4.50 +2.00 at 90

48. 8. Lets do one more

49. Prescription -3.00 +5.00 at 180 -1.50 D (subtract working distance) -4.50 +5.00 at 180

50. What about un-rule astigmatism angles??

51. 9. Oblique reflex…

52. Prescription -3.00 +2.00 at 120 -1.50 D (subtract working distance) -4.50 +2.00 at 120

53. Problems in Retinoscopy Possible causes Solutions 1. Reflex may not be visible - Opaque/ hazy media Use mydriatics - Small pupil Use mydriatics - High degree of refractive error Keep on follow up 2. Varying/ Changing retinoscopic findings - Wandering fixation Give a specific target - Abnormally active accommodation Fogging technique Cycloplegic refraction in young 3. Scissor reflex - High astigmatism Rotate retinoscopic illumination to find angle where scissor reflex is minimum - Nebular corneal opacities Increase illumination to decrease pupil diameter Spot retinoscopy

54. Problems in Retinoscopy Possible causes Solutions 4. Conflicting or triangular Shadows - Irregular astigmatism Do keratometry & subjective refraction & prescribe minimum power that gives maximum visual acuity - Keratoconus Relate refraction to visual acuity Perform corneal topography Do keratometry & subjective refraction 2. Spherical aberration - Positive aberration (in normal accommodating lens) Increase retinoscope illumination to decrease pupil diameter Concentrate on central bright glow - Negative aberration (more in lenticular nuclear sclerosis) Increase retinoscope illumination Perform dilated retinoscopy

55. Reasons for false reading Inexperience Not aligning with visual axis of the patient Definite working distance is not maintained Lack of patient’s accommodation Defect in trial lenses Lack of patient’s co-ordination

56. Non refractive uses of retinoscopy Opacities in the lens & iris – dark areas against the red background Extensive transillumination defects in uveitis or pigment dispersion syndrome – bright radial streaks on the iris Keratoconus distorts the reflex & produces a swirling motion Retinal detachment involving the central area will distort the reflecting surface & a grey reflex is seen

57. Summary

58. Summary

59. Thank you