Pediatric refraction

BEST WAY TO LEARN PAEDIATRIC REFRACTION

1. PEDIATRIC REFRACTION 1 YASHASWEE BHATTARAI BOPTOM 3 RD YEAR BVDUMC SCHOOL OF OPTOMETRY [email protected]

2. How is it different from normal refraction?????? Objective Refraction is usually used to determine refractive status of infants and preverbal children Meticulously and accurately done Great expertise is necessary Should understand Emmetropization and relation between state of BSV and refractive status of child Techniques must be easily understandable Cycloplegic Refraction is preferable due to active accomodation in child 2

3. REFRACTIVE STATUS OF CHILDREN FIRST YEAR OF LIFE 3-5 YEARS OLD ADOLESCENCE SPHERICAL REFRACTION Healthy neonates are hyperopic (+2.00 D) PREMATURE NEWBORNS Birth weight <2500gm= -1 to -10 D (-4.00 D) mostly myopic and can become emmetropic as age increases Some hyperopic (+5D) ASTIGMATISM Uncommon Sometime +1 D present ANISOMETROPIA Length of Globe increases (5mm from birth to 3 yrs) Process of emmetropization during 1st yr of life SPHERICAL REFRACTION ASTIGMATISM ANISOMETROPIA Mostlly emmetropic More myopic than hyperopic If myopic at 5-6 yrs= >myopia >+1.50D hyperopic at 5-6yrs = mild hyperopic at 13 -14 yrs Spherical Refraction +0.50D to +1.00D = emmetropic at 13-14yrs Spherical Refraction 0.00D - +0.50= myopic by 13-14 yrs NB- AS AGE INCREASES SIZE OF EYE INCEREASES 3

4. Types of pediatric refraction 4 SUBJECTIVE REFRACTION WITH/WITHOUT CYCLOPLEGIGS OBJECTIVE REFRACTION STATIC and NEAR RETINOSCOPY DYANAMIC MANIFEST CYCLOPLEGICS MEM BELL BOOK CHROMORETINOSCOPY

5. CHOICE OF REFRACTION FOR DIFFERENT AGE GROUPS 5 Mohindra Near Retinoscopy Retinoscopy with and without cycloplegics Photorefraction Keratometry / Placido’s disc/ Keratoscope Retinoscopy with or without cycloplegics Distance (by showing TV for fixation) Dyanamic - MEM for Near Book Retinoscopy Subjective Refraction Keratometry Manifest/ Cycloplegic Retinoscopy Dynamic Retinoscopy Subjective Refraction FUNDUS EVALUATION IN ALL

6. CYCLOPLEGIC REFRACTION CYCLOPLEGICS are the drugs that paralyze the ciliary muscles resulting in loss of accommodation and secondarily dilatation of Pupil 6

7. WHY CYCLOPLEGIC REFRACTION?? To stop eye’s ability to auto focus or accommodate in order to determine true prescription When the eye contracts and relaxes the lens changes its shape Cycloplegics paralyses ciliary muscles and lens can nolonger change its shape and there is no chance of accommodation In children they have the great ability to vary their accommodation 7

8. HyPERMETROPIA 8

9. MECHANISM OF ACTION 9

10. 10 Visual Acuity (Near/Distance) Pupillary Reflex and size under room illumination Manifest Refraction History Medical Allergic Emotional Hyperemia in conjunctiva Accommodation and Binocular status AC/A Relation Ac angle and IOP MEASUREMENTS TO BE DONE BEFORE INSTILLING CYCLOPLEGICS

11. Ideal cycloplegics should have Rapid onset Full Paralysis of accommodation Sufficient duration to allow accurate assessment of refraction Rapid recovery of accommodation Dissociation from cycloplegic effect from mydriatic effect Absence of local and systemic side effects Capacity of safe administration by appropriate person 11

12. CHOICE OF CYCLOPLEGICS NAME AGE CONCENTRATION START OF EFFECT DURATION TONUS ALLOWANCE/ RESIDUAL ACCOMMODATION ATROPINE 0-7 years 1% 1 drop- twice a day-3 days Cycloplegic =30mins to 3 days 10-14days PMT-14Days TA= +1.5 D RA= 0 CYCLOPENTOLATE 7-15 years 7-12yrs= 1% 12-15yr=0.5% 1 drop 15-20mins -2 nd drop Cycloplegics = few mins Maximizes in 30-60mins 24-48hrs PMT-2days TA=+0.75D/0.5D RA= +1 D HOMATROPINE 1-15 years 1% 2% 5% 2%- Common 1 drop repeated twice after 10 mins ) starts in 15 mins Maximizes in 45-90 mins 24-48 hrs PMT- 2 days TA= +0.75D RA=+0.75D TROPICAMIDE ALL 0.5%, 1% 2 drops after 10 mins 4 drops total Few mins Maximizes in 30 mins 6-8 hrs TA=0/<0.5 D RA=+1.5D 12

13. CHOICE OF CYCLOPLEGICS SCHOOL AGED CHILD 1% CYCLOPENTOLATE 0.5% PROPARACAINE (Aid ocular absorption) Let child rub eyes to facilitate absorption Children with dark iris pigmentation and excessive body weight may require additional drop within 5 minutes to allow cycloplegia . 13

14. According to the patients age we select the type of drug Cyclopentolate is usual drug of choice although it is not as effective as atropine in inhibiting astigmatism because a) Reasonabely powerful b)fast acting –produce cycloplegia within 45-90 mins and lose effectiveness within 3-4 hrs c)relatively safe Tropicamide is fast acting mydriatic but does not inhibit accomodation sufficiently to satisfy requirement of cycloplegic examination Instill the selected cycloplegic according to the dosage After refraction we get certain number of Refractive value We deduct the tonus allowance 14

15. EG#1 For eg If 1% attropine is instilled in a child of 1 and half years Retinoscopy is done at the distance of 1m (example) You get +5.00D = Gross Retinoscopiy value +5.00 D – 1.00 D = +4.00 D = Net Retinoscopy value Tonus allowance of atropine = +1.50D Resulting total Power = +4.00D - +1.5D = 2.50D 15

16. 16 SIDE EFFECTS ATROPINE Inhibits action of sweat and salivary gland leading to dryness Tachycardia Hallucination/Dizziness Ataxia Photophobia Blurring of vision Asthenopic symptoms CYCLOPENTOLATE Less side effect Photophobia Blurring of vision Burning sensation Ataxia Dizziness/Confusion Tachycardia HOMATROPINE Less severity than Atropine but same side effects Its is just a derivative so doesn't paralyze ciliary muscles completely TROPICAMIDE Only ocular side effects like Blurring of vision Photophobia Burning sensation

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18. Advantages of cycloplegics Used In cases of hyperopia , esotropia , convergence excess, accomodative spasm and when relative findings cannot be obtained in dry state Helps in accurate refraction and post operative inflammation Reliving pain in uveities Better view of fundus DISADVANTAGES Poor vision and monochromatic abberation Accuracy is required 18

19. RETINOSCOPY Objective means of obtaining Refractive error PRINCIPLE 19

20. NEAR RETINOSCOPY Not a variation of dynamic Retinoscopy Basically a substitute for static Retinoscopy mainly used in infants Done with/without cycloplegics Studies showed the relative +5D underestimation of hyperopia in the procedure done without cycloplegics Mohindra introduced a technique of non- cycloplegic retinoscopy that correlates somehow with cycloplegic findings 20

21. NEAR RETINOSCOPY DIFFERS FROM OTHER FORM OF DYANAMIC RETINOSCOPY IN 3 WAYS 1) It is performed in complete darkness, the only illumination in the room is supplied by retinoscope with child fixating at retinoscope light 2) It is monocular procedure i.e eye not being examined is occluded 3) The adjustment factor of -1.25D is algebrically combined with the spherical component of the gross sphero -cylindrical lens powers 21

22. PROCEDURE The examing room is darkened Intensity of retinoscopy light is kept as minimum Examiner encourages the child to fixate the light by making animal sounds Examiner maintains the retinoscope at the distance of 50 cm from the infant For young infants, the best way to scope are with the infants over parents shoulder or while the infant being fed Lens racks are used to neutralize the retinoscopic motion An adjustment value of -1.25D is algebrically added to the neutrality value to determine the distant refractive state Eg - If the motion is neutral with +1.25D lens in place the infant is emmetropic 22

23. EG#2 Suppose we perform retinoscopy at 50cm Compensatory factor= +2D Average Lag of accommodation in infants 0.75D Total compensation= +2.00 – 0.75 D = +1.25 D Gross Retinoscopy value = +3.00 D Net Retinoscopy Value = +3.00- 1.25 D = +1.75D 23

24. Wesson and colleagues (1990) suggested caution in substituting Mohindra retinoscopy for cycloplegic refraction using and adjustment value They found significant difference between the two techniques in both sphere and cylinder power Mohindra Retinoscopy is adequate for infants who do not have esophoria or esotropia When either of these two exists , uncovering the full amount of latent hyperopia is imperative. 24

25. In 1977 extremely highly correlation between near and cycloplegic refraction was suggested In study reported by Maino et al. (1984) results of Mohindra retinoscopy were not correlating with cycloplegic refraction He stated that predictive value of near refraction was very low and concluded that it was not a good predictor of refractive error It was not capable of identifying hyperopia of +3D or more or astigmatism of >1.00 D Thus concluded that noncycloplegic refraction is not the alternative of cycloplegic standard refraction 25

26. DYNAMIC RETINOSCOPY 26

27. 27 Lead of accommodation- At distance closer than resting point amount of accommodation is less than that required by stimulus Lag of accommodation- At distance beyond resting point amount of accommodation exceeds than that of required

28. Dynamic Retinoscopy Objective test to measure the refractive status of the eye Done at nearpoint (40cm) in order to determine how much plus power is required to achieve neutrality Basically used to measure lead and lag of accommodation Especially useful with young children, whom static retinoscopy is often not feasible. Number of ways have been proposed for carrying out dynamic retinoscopy .

29. The patient is asked to fixate at nearpoint stimulus/ plane of retinoscope No working distance lens power is added or substracted Examiner neutralizes the motion of the retinal reflex. the retinal reflex is neutralized by using plus lenses 0.50D is deducted from the finding and the amount of plus lens power that must be added is patients lag of accomodation And the remaining power will be the patient refractive error.

30. MONOCULAR ESTIMATION METHOD MEM is differ from standard dynamic retinoscopy in two ways: - testing distance is not same for all patients - is the monocular procedure. testing distance is determined by the - physical size - preferred reading distance YOUNG CHILDREN= 8-10 INCHES Though many clinicians choose “Harmon distance” (elbow to knuckle )as testing distance -The retinoscopy mirror is set at plano - The retinoscopy light or lens should not place infront of eye more than 2 sec

31. The specific steps of procedure are: 1.Ask the patient to sit comfortably 2.Fixation target is a white card containing 1 and half inch hole having letters words or pictures according to child’s age. 3.It is printed within one and a half inch of the hole 4. The card is attached to the retinoscope with a clip 5. Retinoscope beam passes through the hole in the card 6. Examiner is seated on the stool slightly below patients eye level so the patients eye is at moderate downgaze while looking at the target

32. 4. The patient Should wear his habitual prescription 5. The examiner takes a position of 10-16 inches from patient 6. The retinoscopy beam is directed toward the bridge of patient’s nose Child is instructed to read the words aloud and examiner quickly moves his vertical streak across the pupil with movement = lag of accommodation beyond the plane convergence Examiner estimates the direction and approximate power of the reflex Lens is placed in one eye to reassess the approximate power If it validates the estimate lens power is recorded and if this does not then procedure is repeated with more appropritae lens

33. Eg #3 With motion of moderate degree\ +0.50D lens in front of one eye If it neutralizes with motion +0.50D is recorded If not +1.00D sphere is selected If neutral motion +1.00 is recorded If against motion 0.75D is recorded Normal +0.50D to +0.75D When lag more than +1.00 D prescribe plus lens for near work 33

34. Book retinoscopy Is the variation of dynamic retinoscopy Patients fixates on a near-situated, accommodation-stimulating target Differ from standard dynamic retinoscopy procedure in following way: - where the fixation target is positioned. - what the examiner observes & - how these observations are interpreted

35. The procedure consists of 3 retinoscopic observation made at a distance of - 15 feets - 7 feets - 20 inches with fixation target in each distance Target is placed at 20 inches for the children who could read The target is book with picture so called as book retinoscopy

36. The goal of the procedure were to look for & record relative brightness of reflex, ranging from dull to bright color of the reflex , ranging from dull red to white Speed, range, promptness, pick up & release motion Meridional difference. Basically observes accomodative state of eye

37. INterpretation REFLEX BRIGHTNESS/ MOVEMENT ATTENTION INCREASED BRIGHTNESS/ Bright reflex Moment when child identifies the target With movement Child’s eye located the target Against Movement Settled Attention and held to target Occilation of against to with to against Relaxed attention Dull reflex Withdrew attention 37 THE REFLEX ON THE BASIS OF COLOUR ARE Dull Red, Dull Pink , Bright Pink, White Pink and Pink

38. BELL RETINOSCOPY The distance between patients &the examiner is 50 cm Target is moving & the examiner is constant The ball is used for the patient attraction target should be interesting enough and suspended on its handle at eye level. No lenses are used If the initial reflex shows “neutral” or “with” motion, move the target ( nt the retinoscope ) towards the patients, until against motion is seen and come back until neutral motion is observed in each principal meridian

39. Neutrality usually occurs when the ball is located about 15-16 inches from the patients face (37cm to 40 cm) resulting in lag of accomodation from 0.50 to 0.75D If the initial reflex shows “against” motion the patients may judge to be over accommodation record the distance between the target and the patient when against motion is seen as the target is pushing toward the patients

40. Interpretation If against motion seen between 15-18 inches, patient is normal If “with” motion seen between 15-18 inches, patients is normal If delayed shift to against motion indicates latent , need for addition plus Always with indicates, needs plus for near Always against motion – myopia If astigmatic reflex – indicates astigmatism

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42. ophthamoscopy Is also effective way to obtaining an objective refractive finding The procedure itself is self-evident Simply determine the lens power to focus the fundus . This will be refractive status of the patients.

43. SUBJECTIVE REFRACTION DONE WITH/WITHOUT CYCLOPLEGICS 43

44. THANK YOU REFERENCE CLINICAL PEDIATRIC OPTOMETRY Leonardo J Press, OD, F.A.A.O Bruce D. Moore, OD, F.A.A.O Pediatric Optometry second edition Jerome Rosner and Joy Rosner Primary Care Optometry Theodore Grosvenor, OD, Ph.D , F.A.A.O Optometric Investigations David. B. Henson. Msc Phd . F.A.A.O 44