Nearsightedness

Overview

Myopia, commonly known as nearsightedness, is a prevalent vision condition characterized by clear vision of close objects but blurry vision of distant ones. This occurs due to either the shape of the eye or specific eye components causing improper refraction of light rays. In myopia, light rays that should focus on the retina at the back of the eye are instead focused in front of it.

Onset of nearsightedness typically occurs during childhood and adolescence, with stability often reached between ages 20 and 40. There is a familial predisposition for myopia.

Routine eye examinations can diagnose nearsightedness, and corrective measures such as eyeglasses, contact lenses, or refractive surgery can be employed to address the blurred vision.

Symptoms

Signs or symptoms of nearsightedness may include:

• Blurred vision when attempting to view distant objects
• The necessity to squint or partially close the eyelids for clear vision
• Eyestrain
• Headaches

For adults with myopia, challenges may emerge in reading street signs or store signage. Some individuals might experience blurry vision in low light conditions, such as during nighttime driving, even if they have clear vision during the day. This particular condition is referred to as night myopia.

In children, difficulties in viewing content on whiteboards or screen projections in the classroom may arise. Younger children might not verbally express vision issues but could display behaviors suggesting visual problems, such as:

• Lack of awareness of distant objects
• Persistent squinting
• Preferring to sit close to the television
• Excessive blinking
• Frequent eye rubbing

Schedule an appointment with an eye care specialist if your child displays signs of vision issues or if a teacher indicates potential problems. For yourself, make an appointment if you observe changes in your vision, encounter difficulties in tasks like driving, or find that the quality of your vision hampers your enjoyment of activities.

In case of the following, seek emergency medical care:

• Flashes of light in one or both eyes
• Sudden appearance of numerous floaters (tiny specks or lines drifting through your field of vision)
• A shadow in your peripheral vision (outer or side vision)
• A haze of gray shadow draped across your sight, reminiscent of a curtain, obscuring either a portion or the entirety of your field of vision.

These signs may indicate a detached retina, a medical emergency requiring prompt treatment. Notably, significant nearsightedness is associated with an elevated risk of retinal detachment.

Regular eye exams

Vision issues or gradual changes may go unnoticed by both children and adults. The American Academy of Ophthalmology advises regular vision screenings to guarantee timely detection and treatment.

Children and adolescents: Your child’s pediatrician or another healthcare provider will perform basic eye examinations to evaluate your child’s eye health at key stages: shortly after birth, between 6 and 12 months old, and again between 12 and 36 months. If any concerns arise, a referral to an ophthalmologist, a medical professional specializing in eye health, may be suggested. Vision screenings, aimed at detecting potential vision issues, can be conducted by a range of healthcare providers including pediatricians, ophthalmologists, and optometrists. These screenings are commonly offered at schools or community centers. Recommended screening frequencies include:

• At least once between ages 3 and 5
• Before starting kindergarten, typically around age 5 or 6
• Annually throughout high school

If a vision problem is detected during a screening, a comprehensive eye examination with an optometrist or ophthalmologist will be necessary.

Adults: The American Academy of Ophthalmology suggests that healthy adults without known vision or eye disease issues should undergo a complete eye exam according to the following schedule:

• At least twice between ages 30 and 39
• Every 2 to 4 years from ages 40 to 54
• Every 1 to 3 years from ages 55 to 64
• Every 1 to 2 years after age 65 Top of Form

For individuals with diabetes, a family history of eye disease, high blood pressure, or other risks related to heart or vascular disease, more frequent eye exams may be necessary. Similarly, those with prescription glasses, contact lenses, or a history of vision correction surgery may require more regular exams. The recommended frequency will be advised by your eye doctor.

Causes

The eye comprises two components responsible for focusing images:

• The cornea, a transparent, dome-shaped front surface of the eye.
• The lens, a clear structure resembling the size and shape of an M&M’s candy.

To perceive vision, light needs to pass through both the cornea and lens of the eye. These structures refract or bend the light, ensuring it is precisely focused on the nerve tissues located at the rear of the eye (retina). These tissues then convert light into signals sent to the brain, facilitating the interpretation of images.

Refractive errors

Nearsightedness, a type of refractive error, arises when the shape or condition of the cornea, or the eye’s shape, leads to an imprecise focusing of incoming light. Typically, nearsightedness stems from an eye that is excessively long or oval-shaped, or from a cornea with an overly steep curve. These alterations cause light rays to converge in front of the retina and cross. As a result, the signals transmitted from the retina to the brain are interpreted as blurred.

Additional refractive errors comprise:

• Farsightedness (hyperopia):  This arises when your eyeball is shorter than normal or your cornea has too little curvature. While some individuals may see distant objects somewhat clearly, nearby objects may appear blurry. Others with hyperopia experience blurry vision at all distances.
• Astigmatism:  This occurs when your cornea or lens exhibits uneven curvature, being more steep in one direction than the other. Consequently, vision becomes distorted or blurry across all distances.

Risk factors

Certain factors may elevate the risk of developing nearsightedness, including:

• Genetics: Nearsightedness often has a familial tendency, with an increased risk if one or both parents are nearsighted.
• Prolonged close-up activities: Extended periods of reading or engaging in other close-up tasks are associated with an elevated risk of nearsightedness.
• Screen time: Research indicates that children who spend extended periods on computers or smart devices may face a higher risk of developing nearsightedness.
• Environmental conditions: Some studies suggest that insufficient time spent outdoors may contribute to an increased risk of nearsightedness.