Visual Impairment in Young
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Questions and Answers

What is a common presenting symptom of congenital glaucoma?

  • Night blindness
  • Watery eye at birth (correct)
  • Loss of peripheral vision
  • Color vision deficiency

Which type of inherited optic atrophy has a mitochondrial inheritance pattern?

  • Leber’s optic neuropathy (correct)
  • Juvenile optic atrophy
  • Behr’s syndrome
  • Congenital optic atrophy

What age range is associated with the onset of juvenile (infantile) optic atrophy?

  • 1–2 years
  • 4–8 years (correct)
  • 11–30 years
  • 6–14 years

What is the final visual acuity commonly associated with congenital optic atrophy?

<p>6/60 [LogMAR 1.0] (D)</p> Signup and view all the answers

Which inherited optic atrophy type is likely to result in the least severe visual loss?

<p>Juvenile optic atrophy (A)</p> Signup and view all the answers

What is the typical refractive state of a normal neonate at birth?

<p>2–3 dioptres of hypermetropia (C)</p> Signup and view all the answers

Which feature of visual development does NOT mature until 4 months of age?

<p>The foveal region (D)</p> Signup and view all the answers

What does the P50 component in the ERG waveform primarily represent?

<p>Macular function (C)</p> Signup and view all the answers

How does visual acuity change by the age of 20-30 months?

<p>Improves to approximately 6/6 (B)</p> Signup and view all the answers

Which component of the ERG waveform correlates with optic nerve function?

<p>N95 component (B)</p> Signup and view all the answers

What is the estimated standard deviation of a full-term newborn's spherical equivalent refractive error?

<p>2 dioptres (C)</p> Signup and view all the answers

What does the Electro-oculography (EOG) primarily assess?

<p>Integrity of the retinal pigment epithelial cells (A)</p> Signup and view all the answers

Which condition is associated with a greater refractive error in children?

<p>Tyrosinase-negative albinism (A)</p> Signup and view all the answers

What occurs to a baby who is emmetropic or myopic at birth during childhood?

<p>They will likely become progressively more myopic. (B)</p> Signup and view all the answers

Which ERG test utilizes bright red flash stimuli?

<p>Cone ERG (C)</p> Signup and view all the answers

At what age do the cells in the lateral geniculate ganglion reach adult size?

<p>At 2 years (C)</p> Signup and view all the answers

What percentage of congenital cataracts is inherited in an autosomal dominant manner?

<p>Approximately 25% (A)</p> Signup and view all the answers

In electrophysiological data interpretation, what is crucial to consider?

<p>Clinical findings (C)</p> Signup and view all the answers

The dark trough/light peak observed in EOG corresponds to which parameter?

<p>Retinal adaptation (A)</p> Signup and view all the answers

What is a common associated condition with congenital cataract?

<p>Microphthalmos (C)</p> Signup and view all the answers

What is the typical diameter of the globe at birth?

<p>16.5 mm (B)</p> Signup and view all the answers

What type of ERG test employs moderately bright white flashes?

<p>30-Hz Flicker ERG (D)</p> Signup and view all the answers

What is the incidence of congenital glaucoma in Western countries?

<p>1 in 10,000 births (C)</p> Signup and view all the answers

Why is early diagnosis of congenital glaucoma important?

<p>It limits field loss and prevents buphthalmos (B)</p> Signup and view all the answers

What is the primary function of the N95 component in the ERG waveform?

<p>Indicate optic nerve function (A)</p> Signup and view all the answers

What is the main characteristic symptom of congenital glaucoma?

<p>Watery eye (C)</p> Signup and view all the answers

Which of the following components does NOT represent a specific ERG waveform?

<p>C wave (D)</p> Signup and view all the answers

What is the key feature of autosomal recessive cataracts in Britain?

<p>More prevalent in communities with consanguinity (A)</p> Signup and view all the answers

Which of these components influence each other in the ERG waveform interpretation?

<p>P50 and N95 components (C)</p> Signup and view all the answers

What does the term 'epiphora' refer to in the context of congenital conditions?

<p>Excessive tearing (B)</p> Signup and view all the answers

What is a critical fact regarding the plasticity of the visual system in young babies?

<p>It offers potential for optic nerve recovery if treated early (D)</p> Signup and view all the answers

What visual capability can a full-term neonate exhibit at birth?

<p>Seeing colors and faces at arm’s length (A)</p> Signup and view all the answers

Why is the type of fixation target crucial during an examination of a term infant's visual function?

<p>Different targets aid in determining the severity of vision loss (A)</p> Signup and view all the answers

At what age should a significant response, like a smile, from an infant indicate good central vision?

<p>6 weeks (C)</p> Signup and view all the answers

What is generally regarded as the most common sign of poor vision in a young baby?

<p>Abnormal eye movements and visual inattention (A)</p> Signup and view all the answers

If a parent expresses concerns about their child's vision, what is the recommended approach?

<p>Always believe the mother and either re-examine or refer (B)</p> Signup and view all the answers

What is considered a less useful clinical test of visual function until around 6 months of age?

<p>Visually directed reaching (D)</p> Signup and view all the answers

Which of the following could indicate the presence of an ocular media opacity in an infant?

<p>Persistent squint (C)</p> Signup and view all the answers

What is a possible indication of visual impairment when observing an infant?

<p>Absence of optokinetic nystagmus (C)</p> Signup and view all the answers

What does the 'a' wave in the ERG represent?

<p>Activity of the photoreceptors (A)</p> Signup and view all the answers

What does a normal cone ERG indicate?

<p>Normal cone function (D)</p> Signup and view all the answers

Which test is used to assess normal rod function?

<p>Dim blue flash ERG (D)</p> Signup and view all the answers

What function does the EOG waveform reflect?

<p>Retinal pigment epithelial function (D)</p> Signup and view all the answers

What is indicated by a normal pattern ERG?

<p>Good macular function (C)</p> Signup and view all the answers

What does a flat tracing in the maximal ERG suggest?

<p>Profound loss of photoreceptor function (B)</p> Signup and view all the answers

Which ERG response would be expected under conditions stimulating rod function?

<p>Rod ERG (D)</p> Signup and view all the answers

Which of the following is NOT assessed by the ERG?

<p>Ganglion cell response (C)</p> Signup and view all the answers

In the EOG, what is the significance of the dark to light rise?

<p>Compares amplitudes in light and dark states (C)</p> Signup and view all the answers

Which wave in the ERG has its origin in the Muller (glial) cells?

<p>b wave (B)</p> Signup and view all the answers

Flashcards

Infant Visual Development

Newborns have a refractive error of 2-3 diopters of hypermetropia and high astigmatism. Their eye diameter grows rapidly to almost adult size within the first year. Also, the foveal region matures by 4 months, neural pathways by 2 years, and optic nerve full myelination by 7 months.

Neonate Refractive Error

Newborns usually have a refractive error of about +2 diopters, with variability (standard deviation) around that value.

Visual Acuity Development

Visual acuity (clarity of vision) gradually improves in children, estimated to reach 6/6 (LogMAR 0.0) by ~2-3 years old.

Early Visual Impairment Causes

Vision problems in young children are often congenital (present at birth) or hereditary.

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Visual Impairment Diagnosis

Diagnosis of visual impairment in children relies on specific features observable in clinical examinations in infants/children.

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Clinical Scenarios for Visually Impaired Infants

Common cases of vision problems in infants involve newborns showing early signs of impairment, newborns with impairment but no obvious eye problems and older children who present with vision difficulties.

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Impairment Variability (Refractive Error)

The variability in refractive error (vision) in children with impairment is greater the earlier the impairment onset, i.e., tyrosinase-negative albinism has a higher variability than Stargardt's disease where the variability is less.

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Myopia Progression

Children born with emmetropia (normal vision) or myopia (nearsightedness) are likely to develop more myopia during childhood and adolescence.

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Neonate Visual Acuity Assessment

Assessing a newborn's vision requires special techniques and patience, differing from adult methods.

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Full-term Neonate Vision

Full-term newborns can see colors and faces and have fixations.

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Fixation in Term Infants

Fixation in term infants is a key clinical test of visual function.

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Face Following in Neonates

Neonates are more likely to follow a face stimulus than a white light stimulus.

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6-week Smile Response

A smile in response to a silent smile shows good central vision at 6 weeks.

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Parental Concerns (Vision)

Parents' concerns about a child's vision should be taken seriously, even if eyes look normal.

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Abnormal Eye Movements

Abnormal eye movements indicate poor vision, with uncoordinated movements signifying greater impairment.

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Leucocoria

A white pupil, often indicative of an opacity of the media.

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ERG Waveform

A visual electrophysiological test measuring the electrical activity in the retina and optic nerve.

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P50 Component

Part of the ERG waveform representing the macular function.

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N95 Component

ERG component signifying optic nerve function.

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Electro-oculography (EOG)

Evaluates the retinal pigment epithelium (RPE) cells.

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Neuroretina Dysfunction

A problem in the layers of the retina.

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Macular Area

Central region of the retina responsible for sharp vision.

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Optic Nerve

The nerve transmitting signals from the retina to the brain.

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Electrophysiology Data

Electrical measurements from the nervous system.

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Clinical Findings

Observations made during a patient examination.

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Inherited Disorders

Conditions caused by gene mutations passed down through families.

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ERG

The ERG (Electroretinogram) is a test that measures the electrical activity of the retina in response to light stimulation.

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a-wave

The 'a' wave on the ERG represents the electrical activity of the photoreceptor cells in the retina.

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b-wave

The 'b' wave on the ERG is generated by the Muller cells, a type of glial cell in the retina.

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Pattern ERG

The Pattern ERG measures the response of the retina to a specific pattern of light, like a checkerboard. It helps assess macular function and optic nerve function.

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P50 Peak

The 'P50' peak on the Pattern ERG indicates normal macular function.

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N95 Trough

The 'N95' trough on the Pattern ERG represents normal optic nerve function.

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Cone ERG

The Cone ERG uses bright red light to test the function of the cone cells in the retina.

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Rod ERG

The Rod ERG uses dim blue light to preferentially stimulate the rod cells in the retina.

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Maximal ERG

The Maximal ERG response gives an overall indication of all photoreceptor function.

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EOG

The EOG (Electrooculogram) measures the electrical potential difference between the front and back of the eye, reflecting the function of the retinal pigment epithelium.

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Retinoblastoma Predisposition

Individuals with congenital cataracts are more likely to develop retinoblastoma, a type of eye cancer. This can be inherited or occur randomly.

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Childhood Cataract Impact

Even with surgery, childhood cataracts can lead to serious vision problems due to amblyopia (lazy eye), especially if treatment is delayed.

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Congenital Cataract Prevalence

Cataracts present at birth or within the first year account for nearly 20% of blindness cases in children under 15 in England and Wales.

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Congenital Glaucoma

A condition present at birth where the eye's drainage system doesn't work properly, leading to increased pressure inside the eye. This can damage the optic nerve and cause vision loss.

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Congenital Cataract Inheritance

Most congenital cataracts are inherited in an autosomal dominant pattern, meaning one copy of the mutated gene is enough to cause the condition.

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Primary Hyperplastic Vitreous

A rare eye condition where abnormal tissue grows in the vitreous humor (the clear gel that fills the eye). This can block light from reaching the retina, causing cloudy vision.

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Inherited Optic Atrophy

A group of disorders where the optic nerve degenerates, causing gradual vision loss. These disorders are often passed down through families.

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Congenital Glaucoma Prevalence

Congenital glaucoma, a condition affecting eye pressure, occurs in about 1 out of every 10,000 newborns in Western countries.

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Congenital Glaucoma Inheritance

While there are several modes of inheritance, congenital glaucoma is usually passed down in an autosomal dominant manner, with the condition appearing in all individuals carrying the gene.

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Juvenile Optic Atrophy

A type of inherited optic atrophy that starts in childhood, usually between 4 and 8 years old. It can cause mild to moderate vision loss.

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Behr's Syndrome

A rare inherited condition that affects vision and hearing. It causes gradual vision loss and deafness, starting between 1 and 9 years old.

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Early Diagnosis of Congenital Glaucoma

Recognizing congenital glaucoma early is crucial as it can prevent vision loss and excess eye growth (buphthalmos) by reducing eye pressure.

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Presenting Signs of Congenital Glaucoma

A common symptom of congenital glaucoma is a 'watery eye' (epiphora). It's important to distinguish this from nasolacrimal duct obstruction, which typically develops later.

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Study Notes

Presenting Symptoms of Congenital Glaucoma

  • Photophobia (sensitivity to light) is a common presenting symptom.

Inherited Optic Atrophy

  • Leber's Hereditary Optic Neuropathy (LHON) has a mitochondrial inheritance pattern.

Juvenile Optic Atrophy

  • Juvenile (infantile) optic atrophy typically presents between 3 months and 15 years of age.

Visual Acuity in Congenital Optic Atrophy

  • In congenital optic atrophy, the final visual acuity is often 20/200 or worse.

Least Severe Inherited Optic Atrophy

  • Dominant Optic Atrophy usually results in the least severe visual loss.

Neonatal Refractive Error

  • A normal neonate at birth is typically hyperopic (farsighted).

Visual Development at 4 Months

  • Binocular vision (using both eyes together) does not mature until 4 months of age.

ERG Waveform Components

  • The P50 component of the ERG waveform primarily represents cone photoreceptor function.

Visual Acuity Development

  • Visual acuity significantly improves by the age of 20-30 months.

ERG and Optic Nerve Function

  • The a-wave of the ERG waveform correlates with optic nerve function.

Newborn Refractive Error

  • The estimated standard deviation of a full-term newborn's spherical equivalent refractive error is ±1.50 diopters.

Electro-oculography (EOG)

  • EOG primarily assesses retinal pigment epithelium function.

Refractive Errors in Children

  • Myopia (nearsightedness) is associated with a greater refractive error in children.

Emmetropia and Myopia at Birth

  • A baby who is emmetropic (normal vision) or myopic (nearsighted) at birth will typically become myopic during childhood.

ERG Flash Stimuli

  • The cone ERG test utilizes bright red flash stimuli.

Lateral Geniculate Ganglion Development

  • The cells in the lateral geniculate ganglion reach adult size by the age of 4-5 years.

Inheritance of Congenital Cataracts

  • 25% of congenital cataracts are inherited in an autosomal dominant manner.

Electrophysiological Data Interpretation

  • Age is a crucial factor to consider in electrophysiological data interpretation.

EOG Dark Trough/Light Peak

  • The dark trough/light peak observed in EOG corresponds to the S-potential, which reflects the retinal pigment epithelium function.

Congenital Cataract Association

  • Microphthalmia (small eye) is a common associated condition with congenital cataract.

Globe Diameter at Birth

  • The typical diameter of the globe at birth is 16-17 mm.

ERG White Flash Stimuli

  • The "b-wave" ERG test employs moderately bright white flashes.

Congenital Glaucoma Incidence

  • The incidence of congenital glaucoma in Western countries is 1 in 10,000 births.

Early Diagnosis of Congenital Glaucoma

  • Early diagnosis of congenital glaucoma is crucial to prevent irreversible visual loss.

N95 Component Function

  • The N95 component of the ERG waveform primarily represents inner retinal function.

Congenital Glaucoma Symptom

  • The main characteristic symptom of congenital glaucoma is buphthalmos (enlarged eye).

ERG Waveform Components

  • "c-wave" does not represent a specific ERG waveform. It is a component of b-wave in some cases.

Autosomal Recessive Cataracts

  • Autosomal recessive cataracts in Britain show a high prevalence compared to other countries.

ERG Waveform Interrelationships

  • The "a-wave", "b-wave" and "P50" components all influence each other in ERG waveform interpretation.

Epiphora

  • Epiphora refers to excessive tearing in the context of congenital conditions.

Visual System Plasticity

  • The visual system in young babies is highly plastic allowing for adaptation and recovery from certain conditions.

Neonatal Visual Capability

  • A full-term neonate can exhibit light perception at birth.

Fixation Target Significance

  • The type of fixation target is crucial during an examination of a term infant's visual function because it helps determine central visual acuity.

Infant Vision Assessment

  • A significant response, like a smile, from an infant at 4 months should indicate good central vision.

Signs of Poor Vision in Infants

  • Poor fixation or lack of visual tracking are generally regarded as the most common signs of poor vision in a young baby.

Parental Concerns Regarding Vision

  • If a parent expresses concerns about their child's vision, the recommended approach is prompt referral for a comprehensive ophthalmological assessment.

Clinical Assessment of Visual Function

  • Visual evoked potentials (VEP) are considered a less useful clinical test of visual function until around 6 months of age.

Ocular Media Opacity

  • Absent or weak red reflex could indicate the presence of an ocular media opacity in an infant.

Visual Impairment Indicators

  • Poor head control or failure to reach for objects can be possible indications of visual impairment.

ERG 'a' Wave

  • The 'a' wave in the ERG represents photoreceptor response.

Normal Cone ERG

  • A normal cone ERG indicates normal functioning of the cone photoreceptors.

Assessing Rod Function

  • The "b-wave" ERG (with scotopic stimulation) is used to assess normal rod function.

EOG Waveform Function

  • The EOG waveform reflects the retinal pigment epithelium's (RPE) function.

Pattern ERG

  • Normal pattern ERG indicates normal function of the visual pathway from the retina to the cortex.

Flat Maximal ERG

  • A flat tracing in the maximal ERG suggests severe retinal dysfunction.

Rod Stimulation Response

  • "b-wave" ERG with scotopic stimulation would be expected under conditions stimulating rod function.

ERG Assessment

  • The ERG does not assess the central visual pathway.

EOG Dark to Light Rise

  • In the EOG, the dark to light rise is significant as it indicates normal function of the retinal pigment epithelium.

ERG Wave Origin

  • The "b-wave" in the ERG, or electroretinogram, is a significant component that reflects the inner retinal activity following a flash of light. Its genesis is attributed to the Müller cells, which serve as supportive glial cells in the retina. These cells play a critical role in maintaining the structural integrity and physiological balance of the retinal environment. The b-wave is generated as a response to synaptic transmission between photoreceptors and bipolar cells, showcasing the visual signal processing in the retina.

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Visual Impairment in the Young PDF

Description

This quiz explores the causes and diagnostic features of visual impairment in children and adolescents. It covers congenital conditions, clinical presentations, and advances in molecular genetics. Additionally, it delves into the normal visual development and changes occurring from birth to early childhood.

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