Dissociated Vertical Deviation: Complex Childhood Squint Pattern

Essential Insights for Parents of Children with DVD

Table of Contents

• Understanding Dissociated Vertical Deviation (DVD): Causes and Symptoms
• How Does Dissociated Vertical Deviation Differ From Other Squint Types?
• Diagnosing DVD: Assessment Techniques for Latent Vertical Squint
• Non-Surgical Treatment Options for Dissociated Vertical Deviation
• When Is Surgery Recommended for DVD Squint Correction?
• Recovery and Long-Term Management of Childhood DVD
• Psychological Impact of DVD and Supporting Your Child

Understanding Dissociated Vertical Deviation (DVD): Causes and Symptoms

Dissociated Vertical Deviation (DVD) is a complex childhood squint pattern characterised by an upward drift of one eye when the child is tired, daydreaming, or not focusing intently. Unlike typical squints, DVD is not caused by muscle weakness but rather represents a unique disruption in binocular vision development.

The primary cause of DVD is believed to be abnormal development of binocular vision during early childhood. It frequently occurs in children who have experienced infantile esotropia (inward turning of the eyes) and have undergone corrective surgery. Research suggests that approximately 70-90% of children with a history of infantile esotropia will develop DVD.

The key symptoms of DVD include:

• Intermittent upward movement of one or both eyes
• Worsening of symptoms during periods of fatigue or illness
• More noticeable deviation when the child is daydreaming or not concentrating
• The affected eye may appear to rotate slightly outward as it moves upward
• The condition may alternate between eyes or affect both simultaneously

Parents often notice DVD when their child is looking into the distance or when one eye is covered. The upward movement typically occurs gradually rather than suddenly, and the eye returns to normal alignment when the child refocuses attention. This latent vertical squint pattern can be concerning for parents, but understanding its nature is the first step toward appropriate management.

How Does Dissociated Vertical Deviation Differ From Other Squint Types?

Dissociated Vertical Deviation stands apart from other forms of strabismus in several significant ways. Understanding these differences is crucial for proper diagnosis and treatment planning.

Unlike typical vertical squints (hypertropia or hypotropia), DVD is not caused by specific muscle overaction or underaction. Instead, it represents a disruption in the brain’s visual processing system. The key differentiating features include:

• Dissociation vs. Deviation: In standard squints, one eye deviates in relation to the other. In DVD, the movement of one eye occurs independently (is dissociated) from the other eye’s position.
• Latency: DVD is considered a latent condition, meaning it may not be visible all the time and can emerge under certain conditions like fatigue or inattention.
• Bilateral Potential: While many squints consistently affect one eye, DVD can alternate between eyes or affect both simultaneously, though often asymmetrically.
• Associated Movements: DVD frequently includes an outward rotation (extorsion) and sometimes an outward shift (exotropia) of the upward-moving eye.

Another distinguishing characteristic is that DVD typically doesn’t cause significant double vision (diplopia) in children. This is because the brain suppresses the image from the deviating eye during episodes. This contrasts with acquired vertical deviations in adults, which commonly cause troublesome double vision.

DVD also frequently coexists with other eye conditions, particularly infantile esotropia, nystagmus (involuntary eye movements), and inferior oblique overaction. This complex presentation requires specialised assessment by experts in paediatric ophthalmology who can distinguish DVD from other vertical eye movement disorders.

Diagnosing DVD: Assessment Techniques for Latent Vertical Squint

Accurate diagnosis of Dissociated Vertical Deviation requires specialised assessment techniques due to its intermittent nature and unique characteristics. At London Squint Clinic, we employ comprehensive evaluation methods to identify and measure DVD.

The diagnostic process typically includes:

• Cover Test: The most revealing test for DVD involves covering one eye while the child focuses on a target. When the cover is removed, the examiner observes for a downward drift of the previously covered eye, which is characteristic of DVD.
• Alternate Cover Test: By rapidly alternating a cover between eyes, the examiner can provoke and observe the upward movement typical of DVD.
• Prism Measurements: Special prisms are used to quantify the degree of vertical deviation, helping to determine the severity of the condition.
• Visual Acuity Assessment: Testing each eye’s vision helps identify any associated amblyopia (lazy eye).
• Binocular Vision Testing: Evaluates how well the eyes work together and identifies any suppression patterns.

Importantly, DVD must be differentiated from other vertical deviations such as superior oblique palsy or inferior oblique overaction. The key diagnostic feature is that in DVD, the upward movement occurs when visual attention is directed to the other eye or when binocular vision is disrupted.

Early diagnosis is crucial, as DVD can worsen over time if left untreated. Parents should seek evaluation if they notice intermittent upward drifting of one or both eyes, particularly if their child has a history of other eye alignment issues. Our specialists are experienced in detecting subtle signs of DVD even when the condition is not manifesting during the examination.

Non-Surgical Treatment Options for Dissociated Vertical Deviation

Before considering surgical intervention for DVD, several non-surgical approaches may be recommended, particularly for mild to moderate cases. These conservative management strategies aim to improve binocular vision and control the frequency and severity of DVD episodes.

The primary non-surgical treatment options include:

• Spectacle Correction: Addressing any underlying refractive errors (long-sightedness, short-sightedness, or astigmatism) with appropriate glasses can improve overall visual function and sometimes reduce DVD symptoms.
• Prism Therapy: In some cases, specially designed prism lenses can help compensate for the vertical deviation, though their effectiveness for DVD is limited compared to other types of squint.
• Occlusion Therapy: If amblyopia (lazy eye) is present alongside DVD, patching the stronger eye for prescribed periods can help strengthen vision in the weaker eye.
• Vision Therapy Exercises: Specific eye exercises designed to improve binocular coordination may help some children gain better control over their eye alignment.
• Monitoring and Observation: For mild cases that don’t significantly impact appearance or function, careful monitoring may be recommended, as some children show improvement as they mature.

It’s important to note that while these non-surgical approaches can be beneficial, they typically don’t eliminate DVD completely. The condition is related to fundamental neural pathways governing eye alignment, which are difficult to modify through external means alone.

Regular follow-up appointments are essential to assess the effectiveness of non-surgical treatments and to determine if the condition is stable or progressing. Our specialists provide personalised treatment plans based on the severity of DVD, the child’s age, visual development stage, and the presence of any associated conditions.

When Is Surgery Recommended for DVD Squint Correction?

Surgical intervention for Dissociated Vertical Deviation is not always necessary, but certain circumstances make it the most appropriate treatment option. Understanding when surgery provides the best outcome helps families make informed decisions about their child’s care.

Surgery is typically recommended in the following scenarios:

• Significant Cosmetic Concerns: When DVD is frequent and noticeable enough to affect a child’s appearance and potentially impact self-esteem or social interactions.
• Severe or Progressive DVD: Cases where the vertical deviation is large (typically more than 15 prism dioptres) or shows evidence of worsening over time.
• Failure of Conservative Management: When non-surgical approaches have been tried for an appropriate period without adequate improvement.
• Coexisting Eye Conditions: When DVD occurs alongside other eye alignment issues that require surgical correction, such as residual esotropia or inferior oblique overaction.
• Functional Impact: If DVD is affecting visual function, causing head tilting, or interfering with daily activities.

The timing of surgery is an important consideration. Most ophthalmologists prefer to wait until children are at least 4-5 years old, when the pattern of DVD has stabilised and can be more accurately assessed. However, each case is evaluated individually, taking into account the severity of the condition and its impact on the child.

The success rate of DVD surgery is generally good, with approximately 70-80% of patients showing significant improvement. However, it’s important for parents to understand that DVD can sometimes recur or persist partially after surgery, potentially requiring additional procedures. The goal of surgery is substantial improvement rather than complete elimination of the condition in all cases.

Recovery and Long-Term Management of Childhood DVD

Following surgical correction for Dissociated Vertical Deviation, a structured recovery process and ongoing management plan are essential for optimal outcomes. Understanding what to expect helps families navigate the post-operative period with confidence.

The typical recovery timeline includes:

• Immediate Post-operative Period (1-7 days): Children may experience redness, mild discomfort, and watery eyes. Antibiotic and anti-inflammatory eye drops are usually prescribed to prevent infection and reduce inflammation.
• Early Recovery (1-4 weeks): Redness gradually subsides, though some residual pinkness at the surgical site may persist. Children can typically return to school within 1-2 weeks, avoiding swimming and contact sports.
• Stabilisation Period (1-3 months): The final alignment position becomes more apparent as healing progresses. Some fluctuation in alignment is normal during this period.

Long-term management strategies include:

• Regular Follow-up Appointments: Initially at 1 week, 1 month, and 3 months post-surgery, then annually or as recommended by your ophthalmologist.
• Monitoring for Recurrence: DVD can sometimes return months or years after surgery, requiring vigilance and prompt reporting of any changes.
• Vision Assessments: Ongoing evaluation of visual acuity and binocular function to ensure optimal development.
• Addressing Associated Conditions: Management of any coexisting issues such as amblyopia or refractive errors.

Parents should be aware that DVD may not be completely eliminated in all cases, even with successful surgery. The goal is significant improvement rather than perfection. Some children may require additional procedures if substantial DVD persists or recurs.

With appropriate surgical intervention and diligent follow-up care, most children with DVD achieve good cosmetic results and functional improvement. The condition typically becomes less noticeable as children mature, particularly if they’ve had appropriate intervention during the critical period of visual development.

Psychological Impact of DVD and Supporting Your Child

The psychological effects of Dissociated Vertical Deviation extend beyond the physical manifestation of the condition. Children with noticeable eye misalignment may face social and emotional challenges that require thoughtful support from parents, educators, and healthcare providers.

Common psychological impacts include:

• Self-consciousness: Children may become aware of their eye condition, particularly as they enter school age, leading to concerns about appearance.
• Social interactions: Peers may comment on or ask questions about the eye movement, potentially causing embarrassment or social withdrawal.
• Confidence issues: Repeated experiences of being “different” can affect a child’s self-esteem and confidence in social settings.
• Anxiety about treatment: Children may develop fears about doctor visits, eye drops, or potential surgery.

Supportive strategies for parents include:

• Open communication: Discuss the condition with your child in age-appropriate terms, emphasising that many children have different medical needs.
• Preparation for questions: Help your child develop simple explanations about their condition for curious peers.
• Focus on strengths: Encourage activities where your child excels to build confidence in other areas.
• Connect with others: Consider joining support groups where families share experiences with similar conditions.
• School involvement: Ensure teachers understand the condition, particularly if your child requires any accommodations.

It’s important to recognise that successful treatment of DVD often brings significant psychological benefits. Children frequently report improved confidence and social comfort following correction of noticeable eye misalignment. The psychological advantages of treatment should be considered alongside the physical benefits when making decisions about intervention.

At London Squint Clinic, we understand the emotional aspects of eye alignment disorders and provide holistic support throughout the treatment journey. Our approach includes child-friendly explanations, pre-operative preparation, and ongoing encouragement to help children and families navigate both the physical and emotional aspects of DVD management.

Frequently Asked Questions

What causes Dissociated Vertical Deviation (DVD) in children?

Dissociated Vertical Deviation is primarily caused by abnormal development of binocular vision during early childhood. It most commonly occurs in children with a history of infantile esotropia (inward turning eyes), with 70-90% of these children developing DVD. Unlike typical squints, DVD isn’t caused by muscle weakness but represents a disruption in the brain’s visual processing system that controls eye alignment.

How is DVD different from other types of squint?

DVD differs from other squints in several key ways: it involves independent (dissociated) movement of one eye rather than a relational deviation; it’s latent, appearing mainly during fatigue or inattention; it can alternate between eyes or affect both simultaneously; it typically includes an outward rotation of the upward-moving eye; and it rarely causes double vision in children because the brain suppresses the image from the deviating eye.

At what age should DVD be treated with surgery?

Most ophthalmologists recommend waiting until children are at least 4-5 years old before performing DVD surgery. By this age, the pattern of DVD has typically stabilized and can be more accurately assessed. However, the timing depends on individual factors including severity, impact on appearance, functional effects, and the presence of other eye conditions requiring correction. Each case is evaluated individually by specialists.

Can DVD go away on its own without treatment?

DVD rarely resolves completely without intervention, though its visibility may fluctuate. Some mild cases may become less noticeable as children mature and develop better control of their visual system. However, moderate to severe DVD typically persists and may require treatment, especially if it’s cosmetically significant or affects visual function. Regular monitoring is essential even for mild cases.

What is the success rate of surgery for DVD?

The success rate for DVD surgery is generally good, with approximately 70-80% of patients showing significant improvement. However, parents should understand that DVD can sometimes recur or persist partially after surgery, potentially requiring additional procedures. The goal of surgery is substantial improvement rather than complete elimination of the condition in all cases.

How can I help my child cope with the psychological impact of DVD?

Support your child by providing age-appropriate explanations about their condition, preparing them for questions from peers, focusing on their strengths in other areas, connecting with support groups, and ensuring teachers understand the condition. Open communication about the condition helps normalize it, while successful treatment often brings significant psychological benefits including improved confidence and social comfort.

Will my child need glasses after DVD surgery?

The need for glasses after DVD surgery depends on whether your child has underlying refractive errors (long-sightedness, short-sightedness, or astigmatism) that require correction. DVD surgery addresses eye alignment but doesn’t change the eye’s focusing ability. If your child needed glasses before surgery, they will likely continue to need them afterward. Regular vision assessments remain important as part of long-term management following DVD correction.