Amblyopia Excluding Pathology and Differential Diagnosis Steve Leslie
Amblyopia Excluding Pathology, and Differential Diagnosis Steve Leslie B Optom FACBO FCOVD Grad Cert Oc Ther Spec Cert MNOD
Learning objectives n Participants will be able to: n Use a sequential process of patient history and visual and ocular health assessment to; n make an evidence-based diagnosis of amblyopia: n Confidently exclude pathology, and: n Identify an amblyogenic agent.
My motivations: n. Clinical experience n. Specialties of strabismus and amblyopia, acquired brain injury, vision therapy n. Medicolegal opinions n. Risk minimisation
Optometry Australia Entry-level Competency Standards for Optometry 2014: Kiely P, Slater J. Clin Exp Optom 2015; 98: 65– 89
Amblyopia is. . . n A reduction in the visual capacity of one or both eyes that is not improved by refractive correction, AND n There is an identifiable amblyogenic agent, AND n Occurs in the absence of ocular or visual pathway pathology
Tenets of Diagnosing Amblyopia n Identify amblyogenic factor. n Assume amblyopia or strabismus has an underlying serious condition until proven otherwise (within reason). n A diagnosis of amblyopia is a diagnosis by exclusion. n ESPECIALLY IN CHILDREN!
Best practice regarding amblyopia: risk minimisation n. This could have happened to me in practice if my systems are not good, if I don’t have good records, or if I don’t maintain a healthy level of suspicion
K, age 10, referred for VT n n R 6/6, L 6/30 No strabismus on cover test Early history non-contributory R +0. 50, L +1. 75 n ? Significant anisometropia n ? Strabismus n ? Early deprivation n But no strabismus, and no significant history n So check fixation…….
Toxocara
Optometric Assessment n History n Visual acuity n line, letter (crowding), Lea (single) n Refraction and BCVA n Monocular fixation n Fusion ? – n Cover test, phorias n Stereo, Worth 4 Dot n Accommodation n Ocular health
History in assessment of possible amblyopia n Turned eye n Spectacles n Patching n Exercises n Strabismus surgery n Congenital ptosis n Eye injury n “Conjunctivitis” n Medications n Hydrocephalus n Family history n General health
Rule out intracranial pathology by history of “neurological company” n n n n c/o transient obscurations, dim or variable vision Severe ocular pain Headaches, especially during night Vomiting Lethargy Mood changes Record absence of neurological signs If you don’t ask about them, the patient or parent may not tell you!
Optometric Assessment n Strongly recommend dilated fundus evaluation if assessing possibility of amblyopia n Biomicroscopy n Visual fields should be attempted routinely for a diagnosis of amblyopia
Ocular health – front to back n Cornea n Bilateral keratoconus (distorted reflex) n Pupils n Equal reactions, ? Afferent pupil defect n record (-) or (+) n Lenses
Ocular health – front to back n. Dilated pupil fundus examination, especially: n. Optic nerves: clear margins, flat, normal colour, drusen? n. Maculas
Suspicious Signs n Sudden onset esotropia n Head turn n Swollen discs n Blurred disc margins n Disc haemorrhages
Is this a normal retina?
Structural/pathological causes Good assessment rules in/out n Achromatopsia n Coloboma n Myelinated nerve fibres n Retinopathy of prematurity n Degenerative myopia n Hypoplastic optic nerve n Keratoconus n Macula chorioretinal scars n Macular pathology eg Stargardt’s disease n Optic atrophy n Retrobulbar neuritis n Nystagmus n Congenital optic disc pit (serous macular detachment) n Juvenile glaucoma
Amblyopia with pathology n Documented amblyopia does not preclude the possibility of: n co-existing ocular pathology n consequent pathology (especially a childhood amblyope at risk of adult intracranial pathology) n general disease eg diabetes n intracranial pathology n Important to remain vigilant for negative changes in symptoms or acuity or binocular vision function
Having ruled out pathology now consider Amblyogenic Factors n Form deprivation n Significant anisometropia n Constant strabismus
Form deprivation n Congenital/traumatic cataract n Early complete blepharoptosis n Corneal opacity n Hyphaema n Vitreous haemorrhage n Uncontrolled occlusion/penalisation therapy n * The history will reveal visual deprivation!
Constant unilateral strabismus n Amblyopia is very uncommon in intermittent strabismus n Diplopia is very uncommon in established constant strabismus; consider pathology carefully eg: n cranial nerve palsy (fourth, sixth) n cranial neoplasm* increasing esotropia
History for constant strabismus: probable agent? n First observed ? n Constant? n Unilateral or alternating? n Amblyopia is very uncommon in intermittent strabismus n Treatment n glasses, patching, VT/orthoptics, surgery n ? “Company” n injury (head or eye), illness (*viral) n NO diplopia; diplopia suggests a recent change
Amblyopiogenic refractive error n. Almost always commences before age 2: n. Anisometropia (spherical or astigmatic) n. Isoametropia n. Combined aniso-strabismus
Isoametropia n Astigmatism > 2. 5 dioptres n Hyperopia > 5. 0 dioptres n Myopia > 8. 00 dioptres
Anisometropia (difference in power of…) n Astigmatism > 1. 50 dioptres n Hyperopia > 1. 00 dioptre n Myopia > 3. 00 dioptres
Amblyogenic Refractive Errors n. If reduced monocular acuity is associated with any refractive pattern less than the “standards” for amblyogenesis, n. Be very cautious!
Amblyopia commencing after 2 n Late developing constant accommodative strabismus n Increased close work demands (I-devices) n Acute acquired comitant esotropia (AACE) n Typically diplopia n Often no pathology, but…. . • Evaluation and Management of Acute Acquired Comitant Esotropia in Children. Seminars in Ophthalmology 2017 n Diagnosis of “lazy eye” in older person with no previous diagnosis and no amblyogenic factor is very dangerous.
There is no real “critical period” n Success in amblyopia therapy as a function of age: a literature survey. n Birnbaum MH et al. Am J Optom Physiol Opt 1977; 54(5): 269 -75 n 44 years ago! n “. . recent evidence indicates cortical plasticity beyond the “critical period” and recommends that an attempt at treatment should be offered to all amblyopic children (and adults) regardless of age…” n The treatment of amblyopia: current practice and emerging trends. Papageorgiou EL et al. Graefes Arch Clin Exp Ophthalmol 2019; 257, 1061– 1078
Optimal management of amblyopia n PEDIG (ophthalmologists & optometrists): n part time patching, atropine penalization. n Randomized Trial to Evaluate Combined Patching and Atropine for Residual Amblyopia. Arch Ophthalmol 2011; 129(7): 960 -2. n Vision therapy n Amblyopia and the binocular approach to its therapy. Hess RF, Thompson B. Vis Res 2015; 114: 4 -16. n Lee J. Treatment of anisometropic amblyopia using Bangerter foil and vision therapy. Optom Vis Perf 2017; 5(5): 189 -91.
Competency
Competency
Questions?
- Slides: 35