5LMS0072 Heterophoria Investigation & Management 2022 PDF

Investigation & Management of Heterophoria 5LMS0072 Angela Gulati-Roy MSc., BSc. (Hons.), MCOptom, AFHEA University of Hertfordshire  Online lecture etiquette... Schedule a time in your day to listen & review this content Turn off all other devices / remo...

Investigation & Management of Heterophoria 5LMS0072 Angela Gulati-Roy MSc., BSc. (Hons.), MCOptom, AFHEA University of Hertfordshire  Online lecture etiquette... Schedule a time in your day to listen & review this content Turn off all other devices / remove distractions Don’t be PASSIVE  be inter-ACTIVE Note pad & pen (paper/electronic) Scheduled pauses for you to write notes / think about the answers ? Learning Outcomes What will I need to know ? Definition Classification of horizontal heterophoria (De)-Compensation Investigation Management Normal Binocular Single Vision (BSV) Requires 2 eyes: Ideally, forward looking in humans to enable visual axes’ to be parallel Realistically slightly divergent –  ANATOMICAL POSITION OF REST With normal muscle tone & consciousness, axes are > parallel –  PHYSIOLOGICAL POSITION OF REST Combination of all For near tasks, additional cues these cues – proximal & accommodative convergence ‘should’ produce Final adjustment parallel visual – FUSIONAL VERGENCE axes’ @distance & convergent visual  Orthophoria ‘No movement detected’ ‘NMD’ With both eyes uncovered the visual axes are directed towards the fixation target When the eyes are dissociated the visual axes are still directed towards the fixation target What is a heterophoria? A latent deviation or latent strabismus Deviation remains latent under normal viewing conditions due to the fusional reflex Will be observed (& measurable) if fusion is suspended – Dissociation test (cover test) – Distortion test (Maddox Rod) – Independent objects (Maddox Wing) What is a heterophoria? With both eyes uncovered the visual axes are directed towards the fixation target When the eyes are dissociated, i.e. fusion is disrupted, the eyes may deviate from the fixation point = a heterophoria Describing heterophoria Direction of movement Concomitancy ? – is phoria the same irrespective of gaze direction? Fixation distance – 6m, (?6m+), 0.3m Size of movement – gross scale: small / moderate / large – estimate or measure in prism dioptres Quality of recovery movement – rapid / slow – smooth / jerky Compensation ?  Direction of latent movement ? Describes the relative positions of the eyes when fusion is temporarily suspended  SOP  XOP Is a shared & relative  L HyperP (L/R) positioning  R HyperP (R/L) of the 2  IncycloP(nasal) eyes  ExcycloP(temporal) NEVER R & H/V/torsional elements or L can also be combined Position of eye under the cover Concomitancy ? Heterophoria Concomitant (the majority) – Angle (size) of the deviation remains the same in all directions of gaze – Angle may vary over viewing distance Incomitant – Angle of the deviation differs in different Concomitant Incomitant directions of gaze – Typically, the angle may vary on up or down gaze  Fixation distance? only applies for concomitant horizontal heterophoria 4 questions to evaluate... 1.Is the deviation eso or exo? 2.Is the deviation largest at DISTANCE OR NEAR ? 3.What do the eyes ‘normally’ do at that distance; converge or diverge? – Divergence = term used for distance anomalies – Convergence = term used for near anomalies 4.Is it a convergence or divergence failure OR excess ? @6m @Near Divergence insufficiency Convergence insufficiency (weakness) (weakness) Divergence excess Convergence excess Concomitant horizontal heterophoria Classification Esophoria Divergence Convergence Non-specific Weakness Excess (basic or (insufficiency) mixed) D>N N>D N=D (ESO larger at (ESO larger at distance) near) Concomitant horizontal heterophoria Classification Exophoria Divergence Convergence Non-specific excess Weakness (basic or mixed) (insufficiency) D>N N>D N=D (EXO larger at (EXO larger at distance) near) Compensation ? Can be described in terms of being: compensated OR de-compensated For most px’s, heterophoria is a physiological norm, revealed when fusion is disrupted – Asymptomatic – “compensated” If there is stress on BV system: – Symptomatic – “decompensated” Compensated Adequate fusional reserves Heterophoria Patient ‘usually’ symptom free Decompensated Inadequate fusional reserves Patient ‘usually’ symptomatic OR (rarely), px may Compensated Decompensated develop suppression  Deviation may break down & become manifest (heterotropia / strabismus) Factors affecting compensation 1. Increased visual demand – visual stress Excessive screen work Increased close work (students, new job) Increased distance work Poor illumination, reduced contrast Occupations with >> monocular work – Microscope use – Jewellers – Watch makers Increased use of scanning eye movements – computer games, reading on public transport Factors affecting compensation 2. Optical / Refractive – refraction needs to be correct Uncorrected or ill-corrected refractive error – Accommodative demand can affect vergence – ESOphoria may be seen with uncorrected hypermetropia – EXOphoria may be seen with uncorrected myopia – Uncorrected & unequal astigmatism  blur is a dis- incentive to fusion A change from spectacles  CL’s – Loss of ‘helpful’ prismatic effect from spectacles E.g. Myopes will lose BASE IN prism @ near (XOP) Anisometropia / Aniseikonia – Post cataract surgery (unilateral IOL) Factors affecting compensation 3. Physical changes to well-being of px Poor general health Trauma – permanent or transient reduction to fusional reserves Medication – antidepressants, anti-hypertensives may reduce accommodation Recent unilateral eye disease Alcohol – may reduce amplitude of horizontal fusional reserves (? XOP) Pregnancy Fatigue / Anxiety / Worry / Stress Symptoms are a significant predictor of decompensation 1. Due to effort to maintain BSV Eyestrain – Asthenopia – Pain behind eyes, dull ache, task related Headache (location ‘can’ be a predictor) – Frontal in horizontal phoria XOP during the task? SOP referred to the following day? – Occipital in vertical phoria Sore eyes – lid margins, ? Hyperaemia, inflammation General irritation – ? Agitation, ? exhaustion Symptoms are a significant predictor of decompensation 2. Due to a failure to maintain binocular single vision Diplopia – intermittent, after prolonged visual tasks Blurred vision – stress on NV triad – accommodation difficulties HOP: symptoms – ? misinterpretation of diplopia often Monocular comfort intermittent Jumbling of letters & task or fatigue Reduced depth perception (stereopsis) related Adopting abnormal head posture – Nose acts as septum  HOP: symptoms occludes 1 eye are highly likely – Possible vertical phoria -sensory adaptations rare- Symptoms & history ARE KEY (FLOADS / LOFTSEA will help) Some key areas to consider... What are the symptoms? Symptom ONSET, initial trigger How regularly do the symptoms occur? Are the symptoms progressing? Exacerbated by any particular activity? Can they be stopped? Recent changes – GH, medication, sleep patterns, general stress – occupation, visual tasks, workload POH: orthoptic management or referral – Is the issue longstanding / recurrent?  Investigation & Management of Heterophoria 5LMS0072 Angela Gulati-Roy MSc., BSc. (Hons.), MCOptom, AFHEA University of Hertfordshire Investigation of heterophoria  Heterophoria investigation routine Should include the following: Symptom/history evaluation of data VA & refraction Pre & post refraction motor tests (cover test) – Quantification of heterophoria (range of methods) – Fusional reserves (ideal) – Other tests  motility, NPC, AoA, AC/A Sensory tests – Fixation disparity – Foveal suppression tests – Stereopsis  Visual acuity & refraction VA with new & old Rx – Check fitting of existing specs  unwanted prism ?? Need to know level of VA before carrying out further tests unilateral VA may destabilise a previously well controlled phoria – New? Longstanding anisometropia Binoc. VA ‘may’ be reduced or ‘less comfortable’ than monoc. VA’s Remember symptoms from HOP and uncorrected/changed Rx can mimic one another/overlap – up to date & accurate Rx is essential – ? Indications for cycloplegic refraction (esp. with SOP) Remember VA can also be a sign of pathology – Must always consider this, investigate & rule out Motor status tests = physical movement  The ‘ideal’ cover test (recap) To diagnose the condition Will gauge likelihood of compensation Cover-uncover cover test, THEN alternating cover test Assess at distance (& far distance) & near LIGHTS ON to aid your visibility @near: – Position yourself centrally – ‘Can’ compare response to a light & an accommodative target @ near – Accommodative target = 1 line above VA level of weaker eye Close observation of: Direction / Size / Recovery The ‘ideal’ Cover Test (recap) Direction of phoria – ESO/EXO  tendency to show  XOP from mid 20’s onwards – Vertical – Torsional Estimate or Measure SIZE of deviation (small/moderate/large) – Learn how to estimate in prism dioptres – Estimation – quick but > inter-clinician variability – The larger the phoria, the > chance of decompensation (NOT ALWAYS) Note the QUALITY of RECOVERY of either eye – Smooth / Jerky – Fast (rapid) / Slow – Intermittently breaks down to tropia DIY homework! 5ΔD TO SCALE; 1cm of eye movement observed @1m = Prism Cover Test (recap) - heterophoria Precisely quantifies size Use prism to neutralise – Useful for comparison & monitoring the movement seen: Appropriate target Place prism in front of ESO = Base OUT EITHER eye EXO = Base IN (heterophoria) Carry out an alternating HYPER = Base DOWN cover test until a – (in front of HYPER EYE) reversal of the deviation is seen HYPO = Base IN The measurement is – (in front of HYPO EYE) taken as the prism below where reversal occurred Other dissociation tests : Maddox Rod (recap) Series of plano/convex cylinders – Distort & elongate white spot light  appears as red streak – Distance Maddox rod (red) – Near Maddox rod (green) Rod in front of RE, view spot @6m Measure with neutralising prism –  to position line through spot Un-natural, ? encourages a breakdown of fusion Red may stimulate accommodation –  available in white (6m) Useful for small vertical devs. & to assess cyclo/torsional elements Other dissociation tests: Maddox Wing (recap) Vertical Uses septa to dissociate the SCALE eyes View position of arrow against tangent scale Capable of measuring cyclo/torsional elements Very un-natural viewing task Fixed near WD ESO SCALE – may not coincide with problematic WD EXO-SCALE Prism fusional range (recap) = Prism fusion range/amplitude or fusional reserve “the amount of convergence/divergence that can be exerted before fusion is compromised” –Usually to assess ‘relative’ convergence / divergence Accommodative status remains fixed while vergence is altered –Fixed distance (6m, 0.3m) –Can use to assess vertical reserves –Prism bar, rotary prism (variable prism), phoropter ? Measure opposing reserve to phoria direction first –E.g. large XOP  measure ??  Prism fusion range helps to assess control of deviation Px fixates on a target while prism values are gradually increased Carried out subjectively until px reports diplopia Carried out objectively until see fusion break (eye behind prism drifts) Sub-normal fusion range indicates poor control of heterophoria – MUST know norms Can monitor progression – Treatment efficacy ? – Condition deteriorating ?  Horizontal prism fusion range Base in / base out / base up / base down Record: (blur) / break / recovery for near & distance Unbalanced reserves may indicate decompensated HOP ‘Normal’ break point – One direction may be reduced, other may be excessive @Near: 35-40Δ Base OUT Vertical fusional reserves: (convergent/+ve) 3 BaseΔ UP or 3 BaseΔ DOWN 15-20Δ Base IN (divergent/- ve) ‘Normal’ break point @Dist: 15-20 BaseΔ OUT Significance of fusional reserves Decompensated heterophoria – likely findings: XOP = base out reserves reduced (ability to exert convergence) SOP = base in reserves reduced (ability to exert divergence) HyperP = base up reserves reduced (IN FRONT OF HYPER EYE) HypoP = base down reserves reduced (IN FRONT OF HYPO EYE) Sheard’s criteria (for fusional comfort) Opposing fusional reserve > or = 2x phoria size (to blur or break point) e.g. 10ΔXOP (near) Base OUT positive fusional reserve >/= 20Δ Other eye movements Ocular motility examination To ensure no incomitancy (sometimes a muscle weakness may co-exist) Also important with vertical phoria or cyclophoria Divergence weakness SOP (possible Lateral Rectus underaction) Don’t forget convergence & accommodation disorders These can co-exist with heterophoria Convergence; NPC (cms) Accommodation; amplitude (dioptres), facility (cps) AC/A ratio  may help to determine management strategy – The higher the AC/A ratio > easy to manipulate convergence Sensory status tests what is the brain doing ? Fixation disparity (recap) Normal BV, fovea in one eye corresponds with a small area centered on the fovea of the other eye  Panum’s fusional area Ideal is point to point correspondence between the 2 eyes Point to area correspondence ensures no diplopia occurs unless the eye has deviated enough to move the image OUT of Panum’s area Fixation Disparity = If an image still falls within corresponding Panum’s area but NOT on the exact corresponding point (no diplopia) e.g. Mallett Unit, Sheedy disparometer Fixation disparity Only carried out on latent (phoria) deviations (NEVER tropias) Sometimes, fixation disparity co-exists with a compensated heterophoria – No symptoms/no treatment given – BUT important to monitor Usually, fixation disparity is a sign of stress on the binocular system – Symptoms present/treatment given – Can guide treatment method and/or treatment efficacy Use correct prism base direction to allign nonius markers  Exo - Fixation Disparity: (recap) Panum’s fusional space oxo oxo Nonius strips project onto temporal retina Binocular areas of image perceived as straight ahead Monocular areas of image perceived as nasal  Crossed disparity: BASE IN ALLIGNING PRISM  Eso - Fixation Disparity (recap) oxo Panums fusional space oxo Nonius strips project onto nasal retina – Binocular areas of image perceived as straight ahead – Monocular areas of image perceived as temporal Uncrossed disparity: BASE OUT ALLIGNING PRISM  Check the filters before you use it ! Demonstrate normal view 1st Ask for misalignment / instability Stereopsis / StereoAcuity (fine control of deviation) If stereopsis reduced (< 100”) – likely foveal suppression – Symptoms may be limited/absent – MUST treat Know how to use a variety of tests – Instructions – Interpreting & recording results – KNOW developmental AGE NORMS Stereopsis seconds of arc Name of test? Stereopsis range? Indicated px age? Testing conditions? Filters/goggles?  Stereo-acuity minutes of arc Polarising filters Central binocular lock Minutes of arc (20’  5’) Indication of foveal suppression assymptomatic phoria  Investigation & Management of Heterophoria 5LMS0072 Angela Gulati-Roy MSc., BSc. (Hons.), MCOptom, AFHEA University of Hertfordshire Management of decompensated What do you need to know before creating your management plan? Classification (diagnosis) Level of control (compensation) Are there any other ocular/systemic problems? – Convergence / accommodative issue – Incomitancy Formulate management plan – Determine patient motivation  potential for exercises – Existing spectacle wearer (effect of Rx on the deviation) Basic principles Ideally in this order? Remove the cause of decompensation – Simple, but often highly effective – Visual hygiene advice may be all that is needed Refractive correction – Optimise Rx – Rx Modification Orthoptic exercises (active) Prescribe prism RELIEF (passive) Referral Conservative treatment methods Optical – Rx manipulation – Prisms Orthoptic exercises – Retro paper based (but very simple) – Computerised  Non-conservative treatment methods (un-resolved LARGE deviations) If ALL else fails…. Surgery Rarely with phoria Must know EOM’s – Insertions, actions & innervations What are the CLINICAL findings of decompensation that indicate intervention ? Symptoms Signs – Cover test (SPEED & QUALITY of recovery) –  Fusional reserves (Δ, KNOW FR NORMS @D & @N) – Use Sheard’s Criterion –  Binocular visual acuity –  NPC (cms, KNOW NORMS) –  Reduced stereo-acuity / stereopsis Is it appropriate to treat? WHO ? WHEN ? Known aetiology (diagnosis) Symptomatic px’s After refraction in adults Asymptomatic px’s but (cyclo in children) – This must always be at risk of up-to-date decompensation & loss Patient is willing to of binocular functions regularly attend / motivated Enough time to regularly Pathology excluded review patient Colleagues are also able to treat if you are not there Refractive management Careful refraction to optimise Rx & VA’s Advise on use of spectacles (constant wear ?) Add ADDITIONAL +ve / -ve spheres to manipulate vergence – pending AC/A ratio Repeat cover test with manipulated sphere Check VA’s with manipulated sphere +ve lenses will Reduce ESO deviations -ve lenses will Reduce EXO deviations NB: This is dependent on residual levels of accommodation not apppropriate for presbyopes Orthoptic therapy/exercises Horizontal heterophoria NEED to improve positive (base out) fusional vergence in EXOphorias (i.e. convergence) NEED to improve negative (base in) fusional vergence in ESOphorias (i.e divergence) Orthoptic Exercises aka: vision therapy/training, eye training, eye exercises Purpose? Who ? Control of deviation Good GH Extension of fusion Good potential for BSV & amplitude VA good either eye Improvement of Aetiology known NPC/accommodation Motivated & understand Improvement of relative task fusional Enough time to carry convergence/accommod exercises out & attend ation regularly Brock String (physiological diplopia to strengthen convergence/divergence) https://www.youtube.com/watch? v=EGlCVTdNqfw ≈3m string up to 5 wooden beads Dot Card (phys. dipl) Exercising (opposing) prisms Extension of fusion amplitude/range Gradually increase horizontal prism strength while patient maintains BSV (nil diplopia) Lend prism bar or Fresnel’s Exercising prism (this is the opposite to relieving prism) – Strengthen base out range in exophoria Exercise with Base OUT to force convergence – Strengthen base in range in esophoria Exercise with Base IN to force divergence Improvement of Relative Fusional Convergence Remember near triad A change in accommodation will result in a predetermined change in accommodative convergence However if keep accommodation static, can use exercises to exert or relax accommodation to improve and increase flexibility of vergence – Prism bar/flippers/sterograms Aim: to increase fusional range, so that vergence can be exerted/relaxed while accommodation remains fixed +ve Relative Convergence Convergence is exerted in excess of accommodation Manipulate & exercise this in XOP Relative convergence controls deviation whilst static accommodation keeps vision clear Plane of Plane of vergence accommodation -ve Relative Convergence Convergence is relaxed relative to accommodation Manipulate & exercise this in SOP Sufficient accommodation for clear vision without the associated convergence Plane of Plane of accommodation vergence Relative Convergence – How ? Keep plane of accommodation constant Change stimulus to converge 8Δ BI – Prism bar – Or prism flippers Pairs of prisms Alternately present 12 Δ – BO & BI prisms BO – BO +ve relative convergence – BI –ve relative convergence Stereograms – ‘3 cats’ 2 similar pictures with some differing characteristics Px requested to hold the card at approx. 33cms XOP: Px then stares at a near object (pencil) in front of the card – vergence on pencil, accommodation on cats SOP: distance object behind (through) the card (v. difficult) – Accommodation on cats, vergence at more remote target – Transparent sheets help with this Px must not look at the card itself The position of the target is then changed until 3 figures are seen Stereograms +ve relative (increasing) convergence for XOP – Converge to a point closer to the eyes than the card – Homonymous physiological diplopia -ve relative (decreasing) convergence for SOP – Diverge visual axes relative to the card – Heteronymous physiological diplopia Start with this: Aiming for this: Computer based exercises https://computerorthoptics.com/ Exercise regimes Exercise for short periods frequently (little & often) – Repeat each exercise once or twice 5-7 times daily – Do NOT induce accommodative / convergence spasm – Relax visual axes & accommodation after every 1-2 repeats Review regularly every 6/52 Monitor for spasm (if after exercises experience constant diplopia that will not resolve) Warn may have worsening of symptoms initially Prescribing prisms Always, prevent decompensation & or alleviate symptoms – try exercises first, if possible For symptomatic diplopia – Minimum horizontal correction (in horizontal HOP) – Full vertical correction (in vertical HOP)  Correcting (alleviating/neutralising) prism base always OPPOSITE DEVIATION to eye position – Base IN relief for XOP / Base OUT relief for SOP Prisms - good or bad ?  Temporary solution (interim spectacles or Fresnel) for a critical period (e.g. students, imminent exams)  Used in conjunction with exercises to begin with if deviation too large BUT: Prisms only provide RELIEF – Is NOT a cure & does NOT treat the underlying phoria If symptom aetiology is unknown could mask serious ocular or systemic pathology Issues with dependency & prism adaptation Long-term indications for prism relief Elderly patients Small symptom producing vertical deviations Failed to respond to other forms of treatment (refractive/exercises) Unable to comply/limited time for orthoptic exercises Refusal of surgery Unfit for surgery Hyperphoria (HyperP) & Cyclophoria (CycloP) Ensure no underlying incomitancy Hyperphoria – Only treat when symptomatic – If both a horizontal and vertical element: 1. correct vertical element only (prisms work well) 2. correct vertical element with prisms & horizontal element with spheres – Refer if recent onset OR longstanding & symptoms persist Cyclophoria – Repeat near subjective to check cyl axis – Difficult to treat (prisms of no value) Refer the following ! You MUST follow-up your pxs Significant / sudden increase or change in deviation – Urgent referral – Increasing distance SOP (VIN palsy ? Lateral rectus) Large angle heterophoria or failing to respond to treatment – Refer for possible surgery Unexplained reduced visual acuity – Urgent referral if suspicious reduction Anything you are unable to cope with  Investigation & Management of Heterophoria 5LMS0072 Angela Gulati-Roy MSc., BSc. (Hons.), MCOptom, AFHEA University of Hertfordshire Case Management - generic plans POST LECTURE & PRE- TUTORIAL WORK After this lecture & BEFORE the on-site tutorial (1) Supplement your notes from this lecture with these refs: a.Evans, B.J.W (2007), Pickwell’s Binocular Vision Anomalies. 5th ed. Edinburgh: Butterworth Heinemann Elsevier. Part 2 Heterophoria b.Rosenfield M, Logan N. Optometry (2009), Science, techniques and clinical management. 2nd ed. London: Elsevier Ltd. (Binocular Vision Assessment, pp. 244-248) c.Evans, B.J.W. (2008), Optometric Prescribing for Decompensated Heterophoria. Optometry in Practice vol.9 pp. 63-68. (2) Populate the generic management plans for horizontal HOP on the next 4 slides – bring these to the week 34 tutorial (3) Work through the 2 case records on the tutorial section of the ACS module site – bring your notes to the week 34 tutorial Management: Divergence Weakness SOP Cover test movement  Refractive Orthoptic Prisms Surgery (RARE) Management: Convergence Excess SOP Cover test movement  Refractive Orthoptic Prisms Surgery (RARE) Management: Divergence Excess XOP Cover test movement  Refractive Orthoptic Prisms Surgery (RARE) Management: Convergence Weakness XOP Cover test movement  Refractive Orthoptic exercises Prisms Surgery (RARE) Case record analysis Exercise 1: Identify & comment on relevant signs & symptoms of decompensation Identify & comment on possible risk factors / causes for decompensation Classification of the patient’s heterophoria pattern Exercise 2: Decide which additional investigations are indicated and WHY? Specify whether these tests evaluate MOTOR or SENSORY function? Predict the results from these tests? Exercise 3: What is your ‘preferred’ management strategy & why ? (include a plan B)