8.1.4 Flashcards
What is heterotropia?
A condition where the eyes are misaligned and cannot maintain proper binocular fixation.
What are the types of onset for heterotropia?
- Congenital/longstanding
- Acquired (sudden or gradual onset)
What are common symptoms of heterotropia?
- Diplopia (monocular or binocular)
- Asthenopia (eye strain, headaches)
- Cosmesis concerns
- Suppression or adaptation (if longstanding)
What triggers or associations are linked to heterotropia?
- Trauma
- Vascular disease
- Neurological conditions
- Recent illnesses or stress
- Medication history
What is the purpose of the Cover Test in diagnosing heterotropia?
Determines manifest deviation (constant or intermittent).
What does the Alternate Cover Test identify?
Direction and size of deviation.
What does the Prism Cover Test quantify?
Deviation in prism diopters.
What is assessed during an ocular motility assessment?
- Versions (binocular movements)
- Ductions (monocular movements)
- Identifies incomitance (e.g., paralytic squint)
What tests are used for sensory evaluation in heterotropia?
- Worth 4-dot test
- Bagolini lenses
- Refraction
What conditions are ruled out by Slit Lamp Examination & Fundoscopy?
Ocular pathology.
What neurological aspects are evaluated if indicated?
Cranial nerves (III, IV, VI).
What is the management approach for longstanding or decompensated tropia?
- Spectacle Correction
- Prisms
- Occlusion Therapy
- Orthoptic Exercises
What corrections are made with spectacle correction?
Fully correct refractive error, particularly in accommodative esotropia.
What type of prisms are prescribed for mild deviations?
- Fresnel prisms (temporary)
- Ground-in prisms (permanent)
What is the primary action for acquired (sudden-onset) tropia?
Urgent referral if neurological, vascular, or orbital causes are suspected.
What temporary management options are available for acquired tropia?
- Occlusion
- Prisms
- Monitor spontaneous recovery
What is the focus of management for incomitant tropia?
- Monitor for spontaneous recovery
- Address underlying causes
- Orthoptic therapy & prisms
What are the potential benefits of squint surgery?
- Improves ocular alignment and cosmesis
- Reduces or eliminates diplopia
- Enhances binocular function in some cases
What are the limitations and risks associated with squint surgery?
- Success is not guaranteed
- Over- or under-correction may occur
- Risks of general anesthesia, infection, or scarring
What are the driving regulations according to DVLA guidelines for patients with diplopia?
Driving is not permitted unless managed (e.g., prism, occlusion).
What adaptations may be needed for work and daily activities?
Adaptations in tasks requiring depth perception.
What should be discussed with patients regarding prognosis and treatment expectations?
Regular follow-up and realistic outcomes of treatments.
What are the referral criteria for sudden-onset tropia?
Urgent referral to neurology/ophthalmology.
What should be done in primary care before referring a patient with heterotropia?
Fully assess to ensure appropriate urgency.
What aspects of patient-centered care should be discussed?
- Discuss treatment options transparently
- Provide psychological support for cosmetic concerns
What is a key characteristic of a paralytic squint?
Sudden onset due to neurological or mechanical causes
Examples include cranial nerve palsy, stroke, trauma, or myasthenia gravis.
What are the signs of a non-paralytic (concomitant) squint?
Longstanding onset, no diplopia, comitant deviation, normal ocular motility
Often associated with refractive error or decompensating heterophoria.
What test can differentiate between paralytic and non-paralytic squints?
Hess Chart & Maddox Rod
Paralytic squints show incomitant deviations.
What is a common differential diagnosis for horizontal diplopia?
Sixth Nerve (Abducens) Palsy, Third Nerve (Oculomotor) Palsy, Myasthenia Gravis, Thyroid Eye Disease
These conditions may present with varying degrees of ocular misalignment.
What is the next step in management for a patient presenting with diplopia?
Perform a cover test and ocular motility assessment
This helps identify comitant vs. incomitant deviation.
What are surgical options for exotropia?
Bilateral Lateral Rectus Recession, Unilateral Resection & Recession, Medial Rectus Advancement, Adjustable Suture Surgery
The choice depends on the type and severity of exotropia.
What should be assessed in a patient with long-standing esotropia concerned about cosmesis?
Sensory Adaptation, Treatment Options (glasses, prisms, surgery), Risks of surgery
Surgery is elective if the patient is asymptomatic.
What are the limitations of using prisms in heterotropia management?
Limited to small deviations, does not treat underlying cause, cosmetic concerns
Prism adaptation may occur over time.
What are key signs of a third nerve (oculomotor) palsy?
Eye position ‘down and out’, ptosis, diplopia, accommodation deficit, pupil involvement
Pupil involvement suggests a potentially serious cause.
What is the significance of pupil involvement in third nerve palsy?
Suggests a compressive cause, requires emergency referral for neuroimaging
Pupil-sparing palsy is more likely due to microvascular ischemia.
What tests are used to assess cranial nerve IV palsy?
Cover Test, Parks-Bielschowsky Three-Step Test, Maddox Rod Test, ocular motility assessment
Systemic workup is needed if bilateral or progressive.
What tests assess binocular function in heterotropia?
Worth 4-Dot Test, Bagolini Striated Lenses, Synoptophore, Stereopsis Tests, Hess Chart, Prism Adaptation Test
These tests help evaluate suppression and angle of anomaly.
What is the management plan for a patient with recent-onset esotropia and a history of hypertension?
Differentiate causes, assess cranial nerves, urgent referral if red flags, monitor microvascular cases, temporary management with prisms
Address underlying hypertension.
What are the indications for botulinum toxin injections in strabismus?
Acute paralytic strabismus, small-angle deviations, post-surgical residual deviations, alternative for high-risk patients
It is not suitable for chronic deviations.
When should an adult with heterotropia be referred to an ophthalmologist?
Urgent referral for sudden-onset heterotropia, neurological signs; routine for symptomatic diplopia
No referral needed for stable, asymptomatic strabismus.
What factors determine the success of squint surgery?
Type of tropia, angle of deviation, binocular function, surgical technique
Intermittent strabismus has better outcomes than constant.
