class test Flashcards

Question

what is incomitant strabismus

Answer 1

dissociated deviation changes size depending which eye fixates dissociated deviation changes size when the eyes are moved in different positions of gaze

Answer 2

- Onset < 6/12 - Large up to 45^ - Constant angle of deviation - Cross fixates - Usually alternating due to equal VA - Not Accommodative as no significant refractive error - Associated with Dissociated Vertical Divergence (DVD) and latent nystagmus that develops 12-18mths

Answer 3

only present under certain conditions px have NRC, hypermetropia and high AC/A ratio e.g. with accom element, fully accom, conv excess

Answer 4

harmonious ARC - angle on anomaly is equal to the angle of strabismus Unharmonious - angle of anomaly is greater than 0 but less than deviation

Answer 5

occurs in long standing deviation small angle deviation <20^ usually convergent mild amblyopia rare in XT provides useful bsv in manifest strabmismus

Answer 6

small angle <10^ with ARC common stable anisometropia always mildly amblyopic (one line at least) central suppression good but not perfect BSV strong motor fusion

Answer 7

no movement on CT only diagnose with fixation ophthalmoscope and 4^ test ARC and eccentric fixation at same retinal point

Answer 8

Small manifest deviation Less than 10^ Mostly Esotropia but can be exotropia

Answer 9

Manifest deviation will increase on continued dissociation Must measure manifest component with simulated PCT Measure Latent Component with full PCT

Answer 10

light sense form sense Color sense Motion sense

Answer 11

rods - movement and light Cones - colour and central vision

Answer 12

Compensated - well controlled Decompensating = poorly controlled Decompensated = broken down to manifest deviation

Answer 13

ET at near and distance at regular intervals

Answer 14

when px was previously XT/XP

Answer 15

refractive - ET increases on accom, rx reduces size of deviation but doesnt eliminate high AC/A ratio ET = N>D, reduced with +3.00DS but not eliminated

Answer 16

onset gradual - 1-3years hypermetropia anisometropia angle reduces with correction amblyopia poor BSV potential - suppression, possible ARC o/a OF MUSCLES

Answer 17

true - uniocular occlusion, no change in deviation simulated - occlusion increases distance angle

Answer 18

esotropia persists after surgery for a larger angle esotropia

Answer 19

onset = 6mo - 2years N=D Amblyopia common poor bsv prognosis despite age of onset Deviation may increase with time Sx management often needed

Answer 20

onset = 2-8 years N=D intermittent - constant large angle diplopia NRC OM normal Minor injury or short period of uniocular occlusion preceding the onset

Answer 21

gradual onset progressive myopia (high -) ET D>N vertical deviation seen on CT/MRI Long eyes and older px restricted elevation marked abduction limitation

Answer 22

Visual loss so severe that fusion is disrupted due to trauma, retinal detachment or cataract

Answer 23

VA loss often unilateral Age of loss determines deviation - after birth = ET/ XT - childhood = ET - Late childhood/ adult = XT intractable diplopia Large angle

Answer 24

Px with previous Hx of XT

Answer 25

refractive High AC/A - conv excess

Answer 26

Onset 2-5 years Hypermetropia – +1.50-+5.00DS Int ET to an accommodative target Esotropia on near fixation even with full + BSV in distance when corrected ET N>D sgls High AC/A ratio: often 8:1 or more Monocular eye closure seen Equal VA (generally) Suppression at N when ET

Answer 27

ET at near and distance at regular intervals

Answer 28

micro increased in size uncorrected + High AC/A

Answer 29

originally large angle tropia angle reduced to microtropia management ----------------------- surgery exercises Optical treatment

Answer 30

microtropia is the initial defect

Answer 31

bagolini macular worth ligjts polaroid 4 dot test 4^ prism test fixation - visuoscope/ direct ophthalmoscope

Answer 32

aim to maintain best possible VA - refractive error - treat amblyopia - treat associated strab - occlude fellow eye

Answer 33

Heteronymous (crossed) diplopia coming from an uncrossed eye The image from an exotropic eye is seen on the opposite side

Answer 34

true - no change to angle after occlusion or on accommodation simulated -------------------------- fusion - near angle increases after occlusion - normal AC/A Accommodation - near angle increases w accom - high AC/A

Answer 35

Onset >6mo Females>males Better control at near Suppression when manifest, sometimes panoramic vision Manipulation of accommodation and/ or vergence to control Natural history variable Manifest - inattention, poor GH, fatigue, alcohol, bright lights

Answer 36

mono occlusion -> NEAR=DISTANCE ANGLE = SIMULATED DIST XT, NORMAL AC/A (FUSION) NO CHANGE IN ANGLE -> MEASURE NEAR ANGLE W +3.00 -> no change = true int dist xt N=D -> Simulated dist XT w high AC/A (accom)

Answer 37

refractive corection orth exercises alt occlusion teach anti suppression (ONLY IF NRC) concave lenses prisms tinted gls

Answer 38

This is when a patient has an exotropia at near and BSV in the distance. The angle of the deviation at near is 10^ > at near than distance. - It can be true meaning that the angle stays the same after uniocular occlusion or it can be simulated meaning the distance angle increases to equal the near angle after uniocular occlusion . A simulated near exotropia is rarely seen. - The characteristics of a true near exotropia include asthenopic symptoms such as ocular fatigue discomfort, watering and headaches. - The patient usually has equal VA but may complain of diplopia. - They are seen to have poor binocular convergence, NRC ad normal sensory fusion but have reduced positive motor fusion amplitude.

Answer 39

ORDER OF TESTING IS IMPORTANT - Case history - VA- equal - CT (far distance) FD>D>N - Conv - Bagolini - PFR - Stereoacuity - N&D - AC/A- measured in distance - CBA - over accommodate to control so VA reduced - PCT - OM - Lateral incomitance/ A+V patterns - Diagnostic occlusion - Control Score

Answer 40

Exotropia is the initial defect Early onset - Onset < 12 months = infantile XT Decompensated intermittent exotropia - Distance or non specific XT decompensation

Answer 41

Aetiology Characteristics - Onset after 12mo of age - Hx of previously straight (photos) - Constant unilateral XT - Equal VA - amblyopia implies early - Suppression - no diplopia - NRC or ARC - difficult to determine - BSV - difficult to demonstrate - BSV potential post sx - excellent Investigations → Case history - old photos, monoc closure → VA → CT (moderate angle, all distances) → BSV - retinal disparity the strongest stimulus to vergence in exotropes → Potential for BSV - Age - VA (prognosis for fusion) - Prism adaptation - BtxA Differential diagnosis Careful assessment needed… - Make sure it’s not a constant exotropia with dense amblyopia, and not a secondary exotropia

Answer 42

Sensory - Visual loss so severe that fusion is disrupted - Age of visual loss determines the deviation Shortly after birth pathology = ET or XT In childhood = ET Later childhood and adulthood = XT (more common) Aetiology Congenital or acquired vision loss Reversible or irreversible Characteristics → Gradual onset if acquired as adult - dip less → Large angle → Hx of unilateral VA loss → Age of visual loss determines deviation - Shortly after birth = ET or XT - Later childhood/adulthood = XT (more common) Investigation - Case history - Full OE - VA - If aphakic, assess VA potential with refraction corrected - BTxA - as prognosis investigation - Area and density of suppression - PCT (synoptophore, Prism reflection test)

Answer 43

Px with previous hx of esotropia Aetiology Spontaneous - Weak or absent vision - Early onset ET, hypermetropia >5DS, amblyopia - Gradual onset, dip Result of surgical correction Planned - Primary ET c gd bsv potential - Px with poor bsv potential - best left slightly, more stable long term result Unplanned - most - Early - slipped muscle - Late - lack of binocular reflex Characteristics Result of surgical correction Unplanned- most Early - possible slipped muscle, inacurate surgery - Diplopia - Monoc closure (bright light) - Limitation of adduction - presentation 20-30y/o - large XT (45^BI) - older larger

Answer 44

XT persists after surgery for larger angle planned - int XT/ decom x - overcorrection poorly tolerated - diplopia if fully corrected - two stage surgery fro large angle unplanned - concave lenses (smaller angles) - BTxA into recessed LR - BI fresnel prism - further surgery

Answer 45

Aetiology Generally unknown - multifactorial Characteristics Stable ET >30BO (some increase in size) N=D angle No sig refractive error, makes no difference Onset <6mo,generally 3-4mo Alternating - dense amblyopia rare (amblyopia in 41-35% chance post surgery) Cross fixation - bilateral abduction limitation Poor BSV prognosis LMLN - intensity increases on occlusion - possible rotary component DVD - >2 yrs old IO o/a Asymmetric motion VEPs Asymmetry of OKN (N-T abnormal) AHP - Compensate for nystagmus - Compensate abduction limitation - Compensate for DVD (tilt) Investigation Case history - when did parents start noticing squint first Refraction VA CR CT Prism reflections/ Krimsky/ PCT Conv OM Dolls head test Spinning baby test OKN - binoc then monoc, both horiz directions

Answer 46

- An anomaly which occurs on dissociation Aetiology - Unknown - Thought to be related to disruption of binoc function High incidence of latent nystagmus (as high as 100%) Associated with infantile ET - can occur with other constant and intermittent deviations Characteristics Progressive elevation of the eye under the cover Extorsion and latent nystagmus may be associated features Fixation required After onset of strab and nystagmus >2 y/o After surgery for ET Nearly always bilateral - can be very asymmetric, > in distance Unsightly hypertropia - inattention or poor health/ fatigue Elevation similar on ab- and ad- duction - can be spontaneous on versions(nose) - looks like IO o/a AHP - tilt to side of fixing eye A patterns more common SO o/a possible BSV weak if present at all Investigation - measurement is difficult - manifest component measured with spct first - Alt pct - each eye fixing to record asymmetry - may be impossible to reverse movement - can use synoptophore reversed fixation test - differentiate between DVD and hypertropia Bielchowsky darkening wedge test Management Persistent and frequent spontaneous elevation, intervention not often required NON SURGICAL Suggestion of manipulating rx to make fix with most affected eye surgical - depends on - associated IO O/A - DVD unilateral or bilateral - amount of asymmetry - a-pattern with o/a SO

Answer 47

Esotropia that results from use of conv to block/ abolish manifest nystagmus and improve VA

Answer 48

the process by which the refractive state of the eye changes is emmetropization governed by active and passive factors passive - refers to normal eye growth as eye increases, the power of the optical components decrease proportionally reducing refractive error and maintaining emmetropia active - describes a visual feedback mechanism in the control of eye growth (visual experience) he hyperopic element increases during the first six months before any reduction towards emmetropia becomes apparent * a significant reduction in the degree of astigmatism occurs in the infants first year (? until 18 to 48 months) result of increase in eye size, concurrent flattening of cornea nfants have some ability to accommodate to objects at different distance at 2 weeks of age, this ability increases during the first 3 months * cues to accommodation include blur, vergence, chromatic aberration and disparity ? which are used by infants * need for infants to accommodate is much less( depth of focus as a result of a smaller pupil and visual acuity ) * the fact they do not make large accommodative efforts is related to lack of need, as much as lack of ability

Answer 49

condition in which the visual axes deviate from bi foveal fixation when fusion is absent or suspended

Answer 50

neurogenic - angle increased when eyes turned in direction of affected muscle and decreases when turned away mechanical - opposite of neurogenic myogenic

Answer 51

exotropia is the initial defect and present under all conditions - early onset - <12 months = infantile XT

Answer 52

onset 2-3 years orthophoria at distance with bsv ET at near no sig refraction equal va normal ac/a normal accom bsv at near when ET neutralised no change to ET with +

Answer 53

homonymous (uncrossed) - distant object will double when fixating on nearer object - eso deviations - the image of the fixating object is received on the nasal retina of the deviating eye and is therefore projected temporally it results when non-corresponding retinal points are stimulated by the same object Heteronymous (crossed) - nearer object will double when distant object is fixated - exo deviations - in which the image of the fixating object is received on the temporal retina of the deviating eye and is therefore projected nasally it results when non-corresponding retinal points are stimulated by the same object

Answer 54

bagolini macular worth lights polaroid 4 dot test 4^ prism test Fixation - visuoscope/ direct ophthalmoscope

Answer 55

XT at near X in distance with bsv asthenopic symptoms - ocular fatique, discomofrt, watering, headaches diplopia equal VA poor binoc conv NRC Normal sensory fusion Reduced positive motor fusion amplitude

Answer 56

Characteristics Onset >6mo Females>males Better control at near Suppression when manifest, sometimes panoramic vision Manipulation of accommodation and/ or vergence to control Natural history variable Manifest - inattention, poor GH, fatigue, alcohol, bright lights Investigation - aim to assess control ORDER OF TESTING IS IMPORTANT - Case history - VA- equal - CT (far distance) FD>D>N - Conv - Bagolini - PFR - Stereoacuity - N&D - AC/A- measured in distance - CBA - over accommodate to control so VA reduced - PCT - OM - Lateral incomitance/ A+V patterns - Diagnostic occlusion - Control Score

Answer 57

- Onset after 12mo of age - Hx of previously straight (photos) - Constant unilateral XT - Equal VA - amblyopia implies early - Suppression - no diplopia - NRC or ARC - difficult to determine - BSV - difficult to demonstrate - BSV potential post sx - excellent

Answer 58

Px with previous hx of esotropia Aetiology Spontaneous - Weak or absent vision - Early onset ET, hypermetropia >5DS, amblyopia - Gradual onset, dip Result of surgical correction Planned - Primary ET c gd bsv potential - Px with poor bsv potential - best left slightly, more stable long term result Unplanned - most - Early - slipped muscle - Late - lack of binocular reflex Characteristics Result of surgical correction Unplanned- most Early - possible slipped muscle, inacurate surgery - Diplopia - Monoc closure (bright light) - Limitation of adduction - presentation 20-30y/o - large XT (45^BI) - older larger

Answer 59

Case history - when did parents start noticing squint first Refraction VA CR CT Prism reflections/ Krimsky/ PCT Conv OM Dolls head test - checks vestibular ocular reflex Spinning baby test OKN - binoc then monoc, both horiz directions

Answer 60

- An anomaly which occurs on dissociation Aetiology - Unknown - Thought to be related to disruption of binoc function High incidence of latent nystagmus (as high as 100%) Associated with infantile ET - can occur with other constant and intermittent deviations Characteristics Progressive elevation of the eye under the cover Extorsion and latent nystagmus may be associated features Fixation required After onset of strab and nystagmus >2 y/o After surgery for ET Nearly always bilateral - can be very asymmetric, > in distance Unsightly hypertropia - inattention or poor health/ fatigue Elevation similar on ab- and ad- duction - can be spontaneous on versions(nose) - looks like IO o/a AHP - tilt to side of fixing eye A patterns more common SO o/a possible BSV weak if present at all

Answer 61

Persistent and frequent spontaneous elevation, intervention not often required NON SURGICAL Suggestion of manipulating rx to make fix with most affected eye surgery - bilateral MR recession

Answer 62

Definition: Near point of convergence is less than 10cm. Convergence can only by maintained at this distance with effort. Can primary or secondary. Highly treatable. Primary: No other causes for convergence insufficiency are present, including heterophoria

Answer 63

Pre-disposing Factors: Large interpupillary distance Large periods of time only using distance fixation e.g., occupation Precipitating Factors: Fatigue from long periods of close work with/without poor lighting Illness Age Medication/recreational drugs Pregnancy

Answer 64

Patient often reports difficulty with reading or doing close work. Intermittent diplopia during near work. Blurred vision during near work. Frontal headache. Eyestrain. Difficulty concentrating. Movement of print.

Answer 65

Case History Distance and Near Vision Cover Test and Angle of Deviation Assessment of Convergence Accommodation Fusional Amplitude

Answer 66

Correction of Refractive Error Orthoptic Exercises Convergence Exercises: Smooth and Jump convergence Smooth convergence: Pen to nose exercises Jump convergence: Dot card Base in Prisms: Correct near exotropia

Answer 67

The ability to converge is completely lost. May be primary or secondary. Primary: No previous history. Investigation rules out other secondary causes. Secondary: Head Trauma Neurological cause e.g., Parinauds syndrome, encephalitis, multiple sclerosis.

Answer 68

Diplopia for all distances nearer than infinity. Exotropia at near. Ocular motility is normal in primary convergence paralysis. Accommodation may or not be impacted.

Answer 69

Once secondary convergence palsy is ruled out/underlying cause is investigated... Conservative management: Base in prisms to correct exo deviation. Occlusion to prevent diplopia. If accommodation is impacted, hypermetropic prescription in combination with base in prisms. Botox to lateral rectus may be temporary fix

Answer 70

Excessive convergence. May also be associated with accommodation spasm. Transient episodes of convergence. Needs to be differentiated from other causes of esotropia e.g., sixth nerve palsy. Convergence Spasm will demonstrate: Full ocular motility- full abduction. Pupil miosis when convergence. Dolls head- full eye movement. Patients with convergence spasm may be suffering from significant stress in other aspects of their life. Spasm may be exacerbated with testing- not seen when simply chatting to patient about other things. Management: Reassurance and relaxation techniques. Cycloplegic drops and plus lenses may be useful in short term.