Myopia
Myopia
Understanding Myopia
Myopia, commonly known as short-sightedness or near-sightedness, refers to the inability to see distant objects clearly. Individuals with myopia typically have better near vision than far vision due to a condition wherein images of distant objects are focused in front of the retina instead of on it.
Normal Eye
The human eye is incredible. As the eye ball grows in a child, the components of the eye normally develop inThe human eye is truly remarkable. During a child’s growth, the components of the eye develop harmoniously, ensuring that light is accurately focused onto the retina at the rear of the eye. Optimal vision occurs when light aligns precisely on the retinal plane, showcasing nature’s evolutionary design for the normal eye’s development. unison so that light is focused perfectly onto the retina at the back of the eye. Vision is sharpest when light is focused precisely on the retinal plane. This is how nature through evolution had programmed the normal eye to grow.
myopic eye
Myopia arises when there is a deviation from the typical eye growth pattern. In the myopic eye, elongation occurs, leading to a stretched shape where light from distant objects is focused in front of the retina rather than directly on it. Consequently, this misalignment results in blurred vision when observing objects at a distance.
Causes of Myopia
The onset of myopia in children and adolescents is influenced by a combination of genetic predisposition and environmental factors.
A family history marked by myopia serves as a significant risk factor. If one or both parents have short-sightedness, the likelihood of their child developing myopia increases substantially.
Environmental elements play a crucial role, with excessive near tasks like reading, studying, prolonged computer or tablet usage, and extended periods spent indoors impacting myopia development. Notably, children between 6 and 12 years experience rapid eye growth, making this period pivotal for eye health. Factors that promote abnormal elongation growth during this phase heighten the risk of myopia occurrence.
As society progresses through urbanisation, heightened educational demands, and pervasive digital technology usage from early ages, the evolutionary pace of human eyes fails to keep pace with these swift shifts. Consequently, the surge in myopia cases among children and young adults globally has led to its classification as The Myopia Epidemic by eye specialists and researchers.
Degree of myopia
Myopia classification typically hinges on the degree of myopia, denoting the strength of the corrective lens required to enhance vision clarity, quantified in dioptres (D). The extent of myopia correlates with the physical elongation of the eye.
Low Myopia: Ranges from -0.50 to -3.00 dioptres.
Moderate Myopia: Falls between -3.00 and -6.00
dioptres.High Myopia: Extends beyond -6.00 dioptres.
Extreme Myopia: Exceeds -10.00 dioptres.
In certain regions, myopia levels may be expressed in ‘degrees’. For instance, -6.00 dioptres is commonly articulated as 600 degrees of myopia (600) in places like Hong Kong and Southeast Asia, while -10.00 dioptres translates to 1000 degrees of myopia (1000), and so forth.
Risks Associated with Myopia
The implications of myopia extend far beyond the inconvenience of relying on glasses or contact lenses for improved vision. Myopia poses a significant threat to long-term eye health.
While corrective lenses enhance vision by redirecting light onto the retina, they fail to address the fundamental issue:
The physical elongation and stretching of the eye.
This elongation results in a thinner retina, akin to an overextended elastic band, rendering it more vulnerable to damage and ocular diseases. Outlined below are some potential consequences of severe myopia.
It’s essential to note that there is no threshold of ‘safe’ myopia — even moderate myopia can lead to adverse outcomes. However, heightened myopia amplifies the risk of vision impairment over an individual’s lifetime.
Implications of Severe Myopia
The increased thickness and weight of glasses are often necessitated. Employing high-index lenses to alleviate thickness incurs additional costs for each new pair of spectacles
High myopia is correlated with an elevated risk of cataract development, potentially leading to complications pre and post cataract surgery.
There is a heightened likelihood of glaucoma occurrence and the manifestation of severe glaucoma cases in individuals with high myopia.
Myopia tends to trigger early vitreous detachment, resulting in bothersome spots, floaters, and heightened sensitivity to glare.
The retinal thinning characteristic of highly myopic eyes raises the susceptibility to myopic macular degeneration, culminating in central vision loss.
A minor retinal tear can swiftly progress into a retinal detachment, a critical condition demanding prompt detection and management to avert permanent vision impairment.
Symptoms of retinal detachment encompass light flashes, sudden influx of floaters, and a profound shadow traversing the line of sight.
Surgical intervention for retinal detachment repair and vision restoration is intricate, precarious, and invasive. Despite treatment, full visual recovery may not always be achievable.
The Global Rise of Myopia
Myopia has long been recognised as a prevalent vision issue in East Asian nations, with over 80% of adolescents and young adults in regions like Hong Kong, China, Taiwan, Korea, and Singapore experiencing near-sightedness, a figure that has surged beyond 90% in some areas.
However, a notable surge in myopia prevalence is now observable worldwide, extending beyond the boundaries of East Asia to encompass countries like Australia, the United States, and Europe. The incidence of myopia in non-Asian regions has doubled within a single generation and continues to escalate.
Remarkably, historical data illustrated in the graph below reveals that myopia wasn’t as pervasive in East Asia 60 years ago as it is today. With escalating population densities and urbanisation in major Australian cities, the trajectory of myopia prevalence in Australia is projected to mirror that of East Asia. It is anticipated that the normalisation of children and teenagers wearing corrective glasses for near-sightedness in Australia will become more commonplace rather than exceptional.