Presentation is loading. Please wait.

Presentation is loading. Please wait.

An Overview of the Orthoptist Practical Demonstration The Cover Test

Similar presentations

Presentation on theme: "An Overview of the Orthoptist Practical Demonstration The Cover Test"— Presentation transcript:

1 An Overview of the Orthoptist Practical Demonstration The Cover Test
Louise.C.Corp Senior Orthoptist

2 The Role of the Orthoptist
Assess and Manage: Vision Defects (Amblyopia) Vision Screening Defects of Binocular Single Vision (Squint) Ocular Motility Defects Low Vision Assessment Glaucoma Clinics

3 Vision Assessment ‘Hundreds and thousands’ sweet test
Preferential looking with Cardiff cards

4 At age 3 years (matching tests) At age 2 years (naming pictures)
Kay single picture Multiple pictures Sheridan-Gardiner Sonksen-Silver At age 3 years (matching tests) At age 2 years (naming pictures)

5 Expectations of a baby To be able to fix and follow small toys ( e.g. mobile whilst in their cot), lights. Respond to facial expression ( e.g. confirmed by baby smiling, laughing, following parents face on movement ). Baby will attempt to grasp for small toys whilst fixating on them (e.g play frame over the child whilst laying on their back on the floor) At birth - VA approx 6/240 - Improvement rapid in first 6mths with a slower rate up until 12mths

6 Managing Vision Defects
AMBLYOPIA – “Lazy Eye” – Reduced vision in one or both eyes Causes – refractive error, squint, stimulus deprivation (ptosis or cataract) Patches Atropine Penalisation Glasses Blenderm Optical Penalisation

7 Vision Screening Reception Class (4 - 5yrs)
Vision, Check for Squint, Assess BSV, Ocular Motility Pass / Fail Criteria Absentees offered appointment at Community Clinic or re-visit school Referred to: Orthoptic Clinic, Hospital Optician, Consultant, High street Optician 96% coverage % passed % referred to optician % referred to CRH % referred to community clinic as borderline results % absent but offered test at community clinic close to home

8 Defects of Binocular Single Vision Squints

9 There are two types of Strabismus

10 Manifest Strabismus Also known as HETEROTROPIA
When one eye focuses on an object, one eye deviates away from the object Squint is caused by failure of two eyes to look at objects in a coordinated manner. Depends on the normal functioning of brain, optic nerve and twelve muscles around our eyes enabling the two images to superimpose on each other and to form a three dimensional image. HORIZONTAL VERTICAL TORSIONAL

11 Horizontal Convergent - one eye deviates nasally (turns inwards) ESOTROPIA Divergent - one eye deviates temporally (turns outwards) EXOTROPIA

12 What type of squint do these patients have?
RIGHT CONVERGENT SQUINT LEFT DIVERGENT SQUINT Reflex at limbus = 45 Reflex at border of pupil = 15

13 Pseudo-Strabismus Pseudo-Esotropia Pseudo-Exotropia Epicanthic folds
Wide interpupillary distance Short interpupillary distance

14 Essential Infantile Esotropia
Presents within first 6 months Signs Angle large and stable Nystagmus in some cases Normal refraction for age Poor potential for BSV Amblyopia in about 30% Cross fixation

15 Constant Exotropia Congenital Sensory
Presents at birth Disruption of binocular reflexes by acquired lesions, such as cataract Large angle Alternating fixation Normal refraction for age Consecutive - follows previous surgery for esotropia

16 The effect of glasses The effect of accommodation


18 Ocular Motility Defects
Abnormal Eye Movements

Ptosis, mydriasis and cycloplegia Abduction in primary position Normal abduction Intorsion on attempted downgaze Limited adduction Limited elevation Limited depression THE PATIENT WILL SUFFER DIPLOPIA

20 Sixth Nerve Palsy Straight in primary position due to partial recovery
Limitation of right abduction and horizontal diplopia Normal right adduction

21 NERVE PALSIES (III,IV,VI) Be aware in Children
Present with acute onset Squint Complaining of Diplopia Parents notice closing of one eye Urgent referral Serious Pathology More common 6th Nerve Palsy

22 Thyroid Eye Disease Elevation defect - most common
Abduction defect - less common Depression defect - uncommon Adduction defect - rare

23 Right Brown`s Syndrome
Normal elevation in abduction Straight in primary position Limited elevation in adduction Defect to the Superior Oblique Muscle / Tendon



26 What to refer to an Orthoptist ??
Yes Vision concerns – baby not fixing/following small toy / lights Squint Ocular Movement concerns Poor cooperation of patient to ensure no defects Parental Concern BE CAREFUL!! No Family History alone – distant relatives If ? A squint in a child < 4 months old if obvious squint seen then refer if not ask HV to check at 6mths, if still doubtful then refer

27 Does anyone in the group have a squint?
Let`s find out ???

28 The Cover Test “An objective dissociation test to elicit the presence of a manifest or latent deviation. It relies upon the observation of the eyes whilst fixation is maintained and each eye is covered and uncovered in turn”. Firstly, check for a manifest squint before progressing to find a latent squint.

29 Detection of a manifest squint
Ensure patient is looking straight ahead A light is used initially as the position of corneal reflections may indicate a manifest squint  should be central / symmetrical or both displaced slightly nasal Hold fixation target on a level with patients eyes at a 1/3m and ask them to look at it Introduce occluder in front of one eye and watch for any movement of the other eye

30 Continued…………….. If there is no movement, repeat with the occluder in front of the other eye If no movement visible then the patient DOES NOT have a manifest squint at that fixation distance Repeat CT at 6m and far distance if necessary


32 Possible findings for Manifest Squint

33 Continued………… Performed at 1/3m, 6m and far distance
Using accommodative/non-accommodative fixation targets With and without glasses With or without any Abnormal Head Posture In 9 positions of gaze if required

34 Detection of a latent squint
Use appropriate accommodative/non-accommodative targets on a level with the patients eyes at 1/3m Introduce occluder in front of one eye Observe for any movement of the eye behind the occluder once it is removed Repeat with other eye If no movement seen, alternate the occluder from eye to eye (make sure binocularity is avoided)

35 Continued………... A movement maybe more obvious as alternate eyes are occluded Size and direction of movement of the occluded eye as it is moved over to the other eye should be noted Speed at which the eye moves back to the normal position as the occluder is completely removed should be noted (rate of recovery) – indicates strength of BSV or vision level Repeat at 6m

36 Remember……………. Position of eyes on appearance
Check corneal reflections first Ensure no manifest deviation present first Estimate size of deviation (minimal,slight,mod,mkd) and direction of deviation Fixation targets-light,small picture or toy, 6m picture/object Can the manifest deviation alternate or hold fixation

37 Louise.C.Corp Orthoptic Dept Calderdale Royal Hospital 01422 222218
Thank you Louise.C.Corp Orthoptic Dept Calderdale Royal Hospital

Download ppt "An Overview of the Orthoptist Practical Demonstration The Cover Test"

Similar presentations

Ads by Google