There are many aspects to consider when searching for a pair of glasses or getting contact lenses that perfectly fit your needs. But why do you need them in the first place?
Everyone’s eyes are different and contain their own genetic and anatomical information that will determine their quality of vision. Factors such as the shape of the eye, the condition of the retina, and the health of the cornea can all improve or impede the perceptible visual quality someone experiences. While many ocular complications are passed down by genes, some of the more serious diseases - like macular degeneration and glaucoma - can also be influenced by nutrition and overall health. Glasses or contact lenses cannot overcome these debilitating eye diseases.
Refractive conditions (often called refractive errors) are seen fairly often and call for simple, non-invasive solutions via a good prescription. Here, we list some of the most common conditions people are likely to develop in life that can bring about the need for glasses.
Myopia
Myopia, or nearsightedness, is a very common ocular condition in which objects up close are easy to see, but distant objects become blurry. This happens when the physical shape of the eye bends light incorrectly to focus images in front of (rather than along) the retina.
As with each refractive error, myopia is largely hereditary. Myopia is not harmful in most cases and can be easily compensated with myopia glasses or contact lenses. Extreme myopia, however, can potentially be dangerous and increase a person’s risk of developing glaucoma, macular degeneration, and retinal issues down the road. Make routine visits to your eye doctor to watch for any signs of hazardous progression.
Children are more likely to develop myopia if they are engaged in activities close to their faces too often (such as looking at screens). Because their young eyes are still developing, depriving the eyes of proper distance viewing regularly has been shown to stunt ocular growth and can increase the child’s chance of having myopia. This has been known to occur in adults on occasion as well, but the odds of seeing a myopic shift after the eyes have matured are much lower (although adult eyes naturally change as they age).
To help prevent myopia, young people are encouraged to spend more time outside and less time looking at screens. The greater distances of objects outdoors can healthily promote distance vision. Otherwise, glasses, contact lenses, or LASIK surgery can help restore vision.
People with myopia have prescriptions with sphere numbers in the negatives, such as -2.00D.
Hyperopia
The counterpart to myopia is hyperopia, or farsightedness. As the name implies, hyperopic people can see objects far away clearly, but struggle when viewing closer objects. Similar to myopia, hyperopia is caused by an improper eye shape that bends light into focus behind the retina rather than along it. It can either be hereditary or develop as a person ages.
Hyperopia is easier to diagnose in adults. Children who have hyperopia may not notice any problems thanks to their younger eyes’ abilities to squint and strain to see better at different distances. Eye exams are one of the best ways to catch hyperopia early. Just like with myopia, glasses, contacts, and LASIK are all ways to fight hyperopia.
People with hyperopia have prescriptions with sphere numbers in the positives, such as +3.00.
Astigmatism
Astigmatism reduces vision for both distance and near, and is generally present at birth or developed while growing up through life. With astigmatism, the eye is slightly football-shaped, preventing a clear image from reaching the retina.
Some occurrences of astigmatism are mild, but others can be severe enough to render someone nearly blind without optical correction. Extreme astigmatism symptoms can indicate the presence of a condition called keratoconus, wherein the cornea is cone-shaped rather than round and smooth.
Glasses can correct astigmatism, but generally need much higher powers in order to work. This can result in bulkier and heavier lenses in some cases. Special contact lenses designed for astigmatism can also help to bring vision back into focus. Additionally, there are several surgical options that eye doctors may offer patients if their symptoms are particularly troubling.
Amblyopia
We’ve already seen that children are at a greater risk of developing refractive errors than adults. Along those lines, amblyopia is a condition that primarily affects children whose eyes are still developing. It often takes the form of one eye suffering from irregular cornea shape, cloudiness, or eye misalignment, resulting in one eye that has a much harder time with vision than the other one. As the brain starts to notice the bad eye’s inability to function, it will slowly start to favor the good eye, making the other even worse. This is also known as a lazy eye.
Treatment typically includes eye patching the good eye for a time to encourage the bad one to strengthen. If the child is unable to use an eye patch, atropine eye drops can also blur the good eye. Once both eyes are in equilibrium, the treatment will be finished.
However, preventative measures must be taken quickly while the person is still young, as the patching technique takes advantage of a younger child’s rapidly developing and adapting ocular system. This means that amblyopia treatment is far more advantageous for kids rather than adults. Children who grow up with the condition untreated might experience vision problems for life.
Presbyopia
Presbyopia is similar to hyperopia in that it typically favors distant objects over objects up close. However, unlike hyperopia, presbyopia is a condition that usually develops naturally later in people’s lives, whether they were myopic, hyperopic, or neither in their younger years. It is considered to be a normal part of aging and is largely the reason why most older men and women will eventually require prescription glasses (or reading glasses at the very least).
When a person is young, the lens sitting at the front of their eyes is smooth and soft. Later in life, this lens grows rigid and is unable to adapt its shape to different degrees of light as easily. This results in trouble seeing objects close to the face.
Common symptoms of presbyopia include difficulty reading fine print, navigating computer screens, or working with any small details. Another frequent indicator involves a person holding reading materials further from their face in order to make out the words. Even people with myopia will eventually have trouble seeing up close.
Glasses are the most common means of treating presbyopia. If a person does not have any pre-existing refractive errors, reading glasses may be the only necessary precaution.
Special lenses used in cataract surgery can also correct presbyopia attributes so that a person does not need any glasses at all. This can be convenient since cataracts tend to develop around the age when people typically start noticing presbyopia symptoms growing worse (ages 60+). These premium IOLs (intraocular lenses) tend to be expensive, however. In most cases, standard implants can remove the need for all glasses besides reading glasses following cataract surgery.
Refractive Errors vs. Eye Diseases
As previously mentioned, glasses and contact lenses are unable to accommodate eye diseases that occur behind the scenes. This is because glasses alter the light coming into the eye but have no effect on how the inner workings of the ocular system perceives that light. Thus, refractive errors only concern the outer lens of the eye and its roundness (or lack thereof).
Conditions like macular degeneration, glaucoma, cataracts, and other internal diseases that occur inside the eye hinder the light traveling onto the retina. Because these problems sit between a pair of glasses and the retina, no amount of correction offered by glasses will fully overcome the symptoms brought about by these conditions.
Treatments for eye diseases vary, ranging from nutrition changes to eye drops and sometimes surgical intervention. If your glasses are unable to provide clear vision, make sure you check with your eye doctor to see what the issue might be. In most cases you may need nothing more than an updated prescription, but sometimes the actual complication might reside deeper within the eyes.