A person with myopia is unable to see clearly from a distance, either because the front curvature of their eye is too strong or their eyeball is too long. The health concerns associated with myopia arise from the fact that when an individual's eyeball becomes more myopic, they are more likely to develop various ocular diseases in the future. There is a greater risk of developing retinal detachment, glaucoma, cataracts, and macular degeneration, all of which can adversely affect your vision. In order to prevent that from happening, eye doctors take all possible measures to slow down myopia progression in young patients.
What are some risk factors that can increase your chances of myopia and progressing at a faster rate?
One of the risk factors for myopia is your family history; if one or both of your parents are myopic, your chances of becoming myopic are greatly increased. Ethnicity is also a risk factor. If you're asian, you're at a much higher risk of progressing faster than other ethnicities. A person who spends less than 90 minutes outside is also at greater risk of developing myopia and progressing at a faster rate. Patients who spend a considerable amount of time looking at their phones or screens, overworking, overshining, and overworking when performing near tasks may also experience faster progression of myopia. Finally a child who develops myopia at a younger age is at a higher risk than a child that starts later in childhood.
How do optometrists determine the progression rate of myopia in patients?
Refractive error
Myopia progression is measured in two ways by optometrists. Using this method, the refractive error of the patient is examined, which means looking at their prescription, specifically how much the minus prescription increases every year. There is a certain standard based on a patient's age that specifies how much a patient's myopia should have progressed over a year. A patient whose myopia progresses more than the normal amount or whose myopia started at a younger age is at a higher risk of medium or high myopia which increases their risks of vision threatening eye disease as they age. If the child’s minus prescription is concerning, their eye doctor may enroll them in the myopia management program or tweak the treatment if they are already enrolled in the program.
Axial length
A patient's axial length is also taken into consideration by eye doctors which is the distance from the front part of the eye to the back part of the eye. There are certain norms for how long an eyeball should be and how fast the eyeball should grow per year, depending on the patient's age, ethnicity, and gender. For example, if a patient is under the age of 8 and they are emmetropic, meaning they do not have a prescription and no refractive errors, then their axial length increasing rate is 0.2 mm each year. On the other hand, if the child is myopic and under the age of 8, the axial length increasing rate is 0.34 mm each year. An eye doctor would use axial length measurements, and if they see the axial length of the patient increasing at a higher rate than normal, that is an indication that the patient's myopia is getting worse, so they would need to intervene, start a new treatment or tweak the existing treatment. In some cases, measuring the axial length of a person can be even more sensitive than checking their minus prescription, since there can be changes to their axial length before any changes to their prescription number.
Thus, these factors can help us determine whether our patients' myopia is progressing or not.
