Introduction

Children use their eyes to navigate the visually complex modern world, making vision crucial for normal development, social interaction and full participation in society. The eye is a complex camera-like structure that focuses and detects light and sends information to the brain, where our visual representation of the world is shaped. In most cases, the eye develops and functions normally. However, environmental factors, diet or genetics can lead to issues that significantly impact a child's quality of life and future development. This article explores common eye problems in children, what clues to look out for and the treatment options available.

Common eye problems In children

Lazy eye

Lazy eye, or amblyopia, is a neurodevelopmental eye disorder in which the information from one eye is not processed fully by the brain.¹ Over time, the brain increasingly favours one eye over the other, leading to decreased function in the affected eye. Lazy eye occurs in approximately  3-5% of people. It has several known causes, including:

• Poor alignment of the eyes (strabismus)
• Irregular eye shape
• A difference in refractive error between the eyes (for example, one eye being farsighted and the other being nearsighted)
• Clouding of the lens of the affected eye

As with many eye disorders, early detection is important as it allows progressive sight loss to be prevented with targeted treatment. Treatment for lazy eyes usually involves correcting the underlying cause and encouraging children to use the affected eye more. Common treatment options include prescription glasses, eye patches and vision therapy exercises designed to improve coordination and focus.²

Strabismus

Strabismus, usually referred to as crossed eyes, is a condition where the eyes are not properly aligned with each other when focusing on an object.³ As a result, one eye tends to look towards the object while the other looks to the sides, above and below. For this reason, strabismus mimics lazy eye but is in reality a different disorder that is often caused by neurological or anatomical problems or genetic factors. Early treatment is crucial to prevent the development of amblyopia (or lazy eye), where the brain starts to ignore the input from the misaligned eye. Treatment options include:

• Use of glasses
• Eye muscle exercises
• Surgery 

It’s important to be on the lookout for noticeable eye misalignment or frequent squinting or head tilting in children. If these behaviours seem to be persistent, it’s important to seek medical advice to ensure the child receives early treatment. Early detection and intervention are key to preventing complications such as amblyopia and ensuring proper visual development.

Colour blindness

Colour blindness, or colour vision deficiency, is a disease where the ability to either see colour or differentiate between colours is suboptimal.⁴ It occurs when the cells responsible for detecting colour in the retina (cone cells) do not function properly. 

Colour blindness is fairly diverse and can range from minor issues with colour perception to the total lack of ability to see colour. Minor cases of colour blindness are not particularly troublesome, and it’s possible to adapt and develop coping mechanisms. However, depending on where the person lives, the disorder could make it difficult to pursue some careers, such as:

• Pilots
• Train drivers
• Police officers
• Firefighters
• Some armed forces' roles

Diagnosis is usually performed using a colour vision test like the Ishihara test.⁵ There are no cures for colour blindness, but there are methods to help people live with the symptoms. The inherited eye diseases (IEDs) are caused by genetic changes that affect different cells, tissues and systems within the visual pathway.⁶ Although they are very rare individually, around 1 in 1,000 people globally have an IED.⁷ The genetic changes that cause IEDs can be passed down genetically to a child from their parents, who may be unaware that either are carriers. This is because many IEDs are recessive; both copies of a particular gene (we inherit one copy from the mother and one from the father) must be affected for the disorder to be expressed. As such, IEDs are often unexpected, and it is important to understand the early signs and symptoms if early detection is to be possible. Depending on which genes are impacted, several structures can be affected, including the lens and retina. 

In the long term, research into gene therapies might provide treatments for more severe forms of the disorder.⁴

Although the signs can sometimes be subtle and easily overlooked, it is important to be vigilant for signs of colour blindness in children. For example, they might have difficulty distinguishing different colours or make unusual colour choices when drawing or dressing themselves. A formal and comprehensive colour vision assessment will allow the condition to be managed.

Rare eye disorders in children

Congenital cataracts

Cataracts affect the lens and are often thought of as a disease of the elderly. When they develop at an early age, they are known as congenital cataracts and can threaten sight if not treated. These lesions are caused by variations in genes responsible for producing the proteins that make up our lens, known as crystallins.⁸ Most babies with congenital cataracts require surgery and will need to wear glasses or contact lenses afterwards. Although the treated eyes might still have reduced vision, most children with congenital cataracts go on to live normal lives.

To check children for cataracts, parents and caregivers should look for a noticeable whiteness in the pupil, which can sometimes be seen in photographs taken with a flash. Other reasons for concern are unusual eye movements or problems focussing on objects.

Inherited retinal diseases

Inherited retinal diseases (IRDs) are a vast group of various disorders involving the layer at the back of the eye responsible for detecting light, the retina. Some of the main IRDs are:

• Retinitis pigmentosa: Genetic disorder in which the retinal cells break and eventually die.⁹
• Leber’s congenital amaurosis: A  severe genetic disorder leading to blindness or severe visual impairment at birth or within the first few months of life¹⁰
• Stargardt disease: The most common type of inherited macular degeneration¹¹
• Usher syndrome: A condition characterised  by the combination of partial or total hearing loss and vision loss¹²
• Best Disease: An inherited form of macular degeneration that usually begins in childhood or adolescence¹³

There are some early signs of inherited eye diseases that parents should monitor. In particular, be wary of:

• Excessive sensitivity to light
• Poor visual tracking
• Rapid eye movements

Medical advice should be sought if any of these issues are noticed. Genetic counselling is essential for the parents of children with an IED because there is a chance that children born in the future could develop the same issues. These diseases are the subject of clinical trials, and gene therapies are promising future treatment options.

Preventative measures and eye care tips

Although some of the problems discussed above have a genetic component, there are some steps that can maximise eye health in children and prevent some issues. It is important to protect young eyes from UV rays using hats and UV-protective sunglasses during outdoor activities.¹⁴ Some vitamins and minerals have vital roles in eye health. Ensure children are eating sufficient leafy greens, fish and citrus fruits to maximise the intake of omega-3 fatty acids, lutein and vitamins C and E.

A commonly discussed cause of eye issues is the increasing time children spend looking at screens, which can lead to eye strain. Encourage regular breaks and outdoor activities. Encourage children to hold the device at arm’s length rather than close to the face, as this can also lead to eye strain.

Technological advancements in paediatric eye care

Technology has transformed the diagnosis and treatment of paediatric eye diseases over the past few decades. Due to compliance, eye examination in children is inherently more difficult than in adults. Children are often unwilling to sit still for long periods and might be afraid of large machines. Hand-held retinal scanners allow opticians and ophthalmologists to make children more comfortable during the examinations.¹⁵ Digital screening tools and sensitive genetic testing technologies allow more timely and precise diagnosis of diseases that cannot be detected during routine eye exams. These technologies make it possible to intervene earlier and provide more tailored care.

Conclusion

Eye health is essential for a child’s immediate quality of life and long-term development. Common disorders like lazy eye, strabismus and RIDs like Stargadt disease have one important factor in common: early detection and intervention can have a positive impact on outcomes. Parents and caregivers should be vigilant for the early signs of eye problems and seek medical advice if they notice anything abnormal. Recent advances in technology and our increasing understanding of the genetic causes of eye diseases are leading to more precise and personalised treatments. A proactive approach to eye health in children and cutting-edge diagnostics and treatments will hopefully lead to a future in which children’s sight is not endangered by these diseases.