Ophthalmology: Latent Squint and Heterophoria

Questions and Answers

What characterizes latent squint (heterophoria)?

Eye deviation is apparent without binocular vision.

Only occurs in individuals over the age of 60.

It is a permanent condition with visible symptoms.

The eye remains straight due to binocular vision. (correct)

Which type of phoria involves an outward deviation of the eye?

Exophoria (correct)

Hypophoria

Esophoria

Hyperphoria

What is the primary purpose of the Cover-Uncover Test?

To measure the strength of extraocular muscles.

To assess the patient’s visual acuity.

To diagnose the specific type of heterophoria.

To identify any deviation when binocular vision is disrupted. (correct)

What does the Maddox rod test primarily measure?

The degree and direction of heterophoria. Signup and view all the answers

Which treatment option is typically used as a last resort for heterophoria?

Surgery to correct muscle imbalance. Signup and view all the answers

How prevalent is heterophoria in the general population?

70-80% Signup and view all the answers

Which of the following is NOT a type of heterophoria?

Centriphoria Signup and view all the answers

In a decompensated case of heterophoria, what condition might manifest?

Manifest squint Signup and view all the answers

Which extra-ocular muscle primarily facilitates adduction?

Medial rectus Signup and view all the answers

What primary action is performed by the inferior oblique muscle?

Abduction Signup and view all the answers

According to Sherrington's Law, what happens when the lateral rectus contracts?

Medial rectus relaxes Signup and view all the answers

Which type of movement is defined as the movement of both eyes in the same direction?

Version movement Signup and view all the answers

In the prism-cover test, what is the general formula to determine the angle in degrees?

1½ Prism power (Diopter) Signup and view all the answers

Which of the following best describes the term 'vergence movement'?

Coordinated eye movement towards a target Signup and view all the answers

What is the primary role of agonist muscles in ocular motility?

To contract for the desired eye movement Signup and view all the answers

If the corneal light reflex is noted to be at the pupil margin, what does this indicate regarding angle of squint?

15 degrees Signup and view all the answers

Which of the following is NOT one of the classic symptoms of congenital glaucoma?

Nystagmus Signup and view all the answers

What is the primary inherited pattern of primary congenital glaucoma?

Autosomal recessive Signup and view all the answers

Which of the following types of congenital glaucoma has the highest prevalence?

Infantile glaucoma Signup and view all the answers

What is a significant sign of congenital glaucoma seen in infancy?

Deep anterior chamber Signup and view all the answers

Which of the following statements about secondary congenital glaucoma is true?

It can be triggered by trauma. Signup and view all the answers

What is the most common type of glaucoma overall?

Primary open-angle glaucoma Signup and view all the answers

Which of the following is considered an early sign of congenital glaucoma?

Large globe Signup and view all the answers

What percentage of cases of primary congenital glaucoma manifest before the age of 6 months?

70% Signup and view all the answers

What is a common ocular manifestation associated with rheumatoid arthritis?

Scleritis Signup and view all the answers

Which of the following is a complication of Sjögren syndrome?

Lymphoma Signup and view all the answers

What typical test is used to diagnose Sjögren syndrome?

Schirmer’s test Signup and view all the answers

Which demographic is most likely to be affected by sarcoidosis?

Females of African descent Signup and view all the answers

What is a primary symptom of multiple sclerosis?

Nystagmus Signup and view all the answers

Which autoimmune condition is characterized by dryness of the mouth and eyes?

Sjögren syndrome Signup and view all the answers

Which of the following is NOT a treatment option for sarcoidosis?

Ibuprofen Signup and view all the answers

Which of the following joints is typically spared in rheumatoid arthritis?

Distal interphalangeal joints Signup and view all the answers

What is the primary treatment goal for amblyopia?

Occluding the normal eye Signup and view all the answers

Which type of strabismus involves a large constant alternating angle of deviation?

Infantile esotropia Signup and view all the answers

In the basic principles of squint surgery, what does recession imply?

Shifting the muscle insertion posteriorly Signup and view all the answers

What type of amblyopia develops when one eye is excluded from central cortical activity?

Stimulus deprivation amblyopia Signup and view all the answers

Which of the following is a rule for unilateral squint surgery involving exotropia?

MR resection for esotropia Signup and view all the answers

At what age does amblyopia typically not develop beyond?

6 years Signup and view all the answers

What is a characteristic feature of non-refractive exotropia?

Usually requires large surgical correction Signup and view all the answers

Which type of amblyopia occurs in children with lateral uncorrected errors?

Meridional amblyopia Signup and view all the answers

What is the duration of occlusion therapy to achieve optimal results for amblyopia?

Until visual acuity is fully developed Signup and view all the answers

Which type of squint surgery involves bilateral lateral rectus resection?

Alternating squint for esotropia Signup and view all the answers

Which condition is characterized by inflammation of all layers of the sclera?

Scleritis Signup and view all the answers

What is the most common cause of episcleritis?

Idiopathic Signup and view all the answers

Which symptom is NOT commonly associated with scleritis?

Usually unilateral pain Signup and view all the answers

What type of episcleritis is most prevalent?

Simple diffuse episcleritis Signup and view all the answers

Which type of staphyloma involves bulging associated with keratitis and corneal perforation?

Corneal staphyloma (Anterior) Signup and view all the answers

Which condition is more dangerous and less common than episcleritis?

Scleritis Signup and view all the answers

Which of the following is a treatment option for scleritis?

Immunosuppressive drug in refractory cases Signup and view all the answers

Which extra-ocular muscle originates at the orbital apex?

Superior oblique muscle Signup and view all the answers

Which of the following best describes the characteristic of chronic uveitis?

Insidious onset and often asymptomatic. Signup and view all the answers

What symptom is commonly associated with acute anterior uveitis?

Rapid painful loss of vision. Signup and view all the answers

Which of the following is NOT a cause of acute anterior uveitis?

Hypertension. Signup and view all the answers

What does the presence of aqueous flare indicate?

It indicates active inflammation. Signup and view all the answers

Which type of uveitis involves both the iris and ciliary body?

Anterior uveitis. Signup and view all the answers

How are keratic precipitates classified based on the type of uveitis?

Large for granulomatous and small for non-granulomatous. Signup and view all the answers

Which of the following is an example of a non-infectious cause of uveitis?

Ankylosing spondylitis. Signup and view all the answers

What is the typical duration of symptoms in acute uveitis?

6 weeks or less. Signup and view all the answers

Study Notes

Latent Squint (Heterophoria)

Characterized by a tendency for the eye to deviate due to extraocular muscle (EOM) imbalance while being held straight by binocular vision.
Occurs in 70-80% of the population, with incidence increasing with age.
Causes include mild weakness in the EOM or errors of refraction.

Types of Heterophoria

Exophoria: Tendency for eye to deviate outward.
Esophoria: Tendency for eye to deviate inward.
Hyperphoria: Tendency for eye to deviate upwards.
Hypophoria: Tendency for eye to deviate downwards.
Excyclophoria: Tendency for eye to roll outward.
Incyclophoria: Tendency for eye to roll inward.

Symptoms

Most cases are compensated, showing no symptoms.
Decompensated cases might show manifest squint.

Diagnosis

Cover-Uncover Test: Assessing eye for deviation by covering one eye to disrupt binocular vision.
Maddox Rod Test (Far): Evaluates how a red line appears when an eye is covered; deviation indicates heterophoria strength.
Maddox Wing Test (Near): Assesses vertical and horizontal phoria at a distance of 40 cm using prismatic lenses.

Treatment

Minor errors may require no treatment.
Correct refractive errors.
Consider strengthening weak eye muscles; surgery is a last resort.

Paralytic Squint

Occurs due to paralysis of one or more extraocular muscles, can be partial (paresis) or complete.

Functions of Extra-Ocular Muscles

Horizontal Muscles: Lateral rectus (abduction), medial rectus (adduction).
Vertical Muscles: Superior rectus (elevation), inferior rectus (depression), superior oblique (intorsion), inferior oblique (extorsion).

Ocular Motility Terms

Ductions: Monocular movements controlled by agonist and antagonist muscles.
- Adduction: Movement in one direction.
- Abduction: Movement in the opposite direction.
Version Movement: Simultaneous movement of both eyes in the same direction.
Vergence Movement: Coordinated eye movement, includes convergence (inward) and divergence (outward).

Sherrington's Law

States that when one muscle contracts (agonist), the antagonist relaxes simultaneously.

Angle of Squint Measurement

Corneal Light Reflex (Hirschberg Test): Uses light reflection to assess squint angle.
Prism-Cover Test: Measures angle deviation by determining how much a prism affects the squinting eye.

Inflammation of the Sclera

Episcleritis: Inflammation of superficial sclera, more common, usually unilateral, associated with collagen diseases.
Scleritis: Inflammation of all scleral layers, can be bilateral, often seen in elderly females.

Symptoms of Scleral Inflammation

Episcleritis: Painful not tender, presents with a red eye.
Scleritis: Painful and tender, red eye, may lead to complications like glaucoma and keratitis.

Staphyloma

Bulging of sclera or cornea due to conditions such as keratitis or high intraocular pressure.
Types include anterior (corneal) and posterior staphyloma.

Amblyopia

Defined as decreased visual acuity without correctable pathology.
Develops during critical visual development, primarily in children under 6 years of age.

Treatment of Amblyopia

Occlusion therapy to encourage usage of the amblyopic eye.

Congenital Glaucoma (Buphthalmos)

Caused by developmental anomalies in the anterior chamber angle, it usually manifests during the first 6 months of life.
Symptoms include lacrimation and photophobia; signs include large globe, corneal edema, and increased intraocular pressure.

Strabismus

Types include refractive and non-refractive exotropia, often corrected surgically.
Can occur due to various underlying diseases.

Autoimmune Diseases

Sjögren Syndrome: Autoimmune condition affecting lacrimal and salivary glands, presenting with dry mouth and eyes.
Rheumatoid Arthritis: Autoimmune disease causing symmetrical joint inflammation with ocular manifestations like scleritis and secondary Sjögren syndrome.
Sarcoidosis: Granulomatous inflammation affecting the eye, can lead to various uveitis types.

Multiple Sclerosis

Demyelinating disease with ocular features like optic neuritis.
Typically presents in the 3rd-4th decades of life.

Uveitis

Inflammation of the uveal tract; classified anatomically, clinically, and etiologically.
Acute anterior uveitis is common, caused by infections and autoimmune disorders, causing rapid painful loss of vision and photophobia.

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Description

Explore the condition of latent squint, or heterophoria, in this quiz. Understand its epidemiology, causes, and different types, including exophoria, esophoria, and hyperphoria. Test your knowledge on how this common eye condition affects the population.