Managing Myopia
Myopia (short sightedness) occurs when the eyeball is too long or too powerful resulting in blurred distance vision. People with myopia are unable to read the board at school, or need glasses for driving. Vision for near objects is clear, within a close range. Once someone becomes myopic their vision tends to get worse over time and glasses and contact lenses become stronger. The greatest change is usually in childhood and teen years.
Why do we need to control myopia?
High levels of myopia are associated with increased risk of eye diseases such as glaucoma, cataracts, retinal detachment and macular degeneration later in life.
Can you (really) slow or stop myopia?
Yes! Most people can slow down or stop their eyes from becoming more myopic. This is exciting news which resonates with all parents who are short sighted.
What causes myopia development and progression?
Genetics, individual characteristics and environment.
In the last 10 years, there has been considerable research into finding the environmental factors which cause myopia progression. Much has been learned from work in animal models. Current understanding is the stimulus to axial elongation—and hence to myopia progression—is defocus not in the central retina but in the mid-periphery. In experimental models, peripheral focus has emerged as very important.
Optometrists can help reduce progression of myopia. We evaluate the whole clinical picture, measuring vision and prescription, recording family history, understanding reading habits and outdoor activity. There are different options to correct vision. Research shows us how each option will influence myopia development. We can intervene and hopefully stabilize vision changes
Techniques include progressive/bifocal glasses with reading power, multifocal soft contact lens, prescription eye drops and Ortho-K contact lenses to reshape the eye. When we have completed an eye examination we can discuss each of these options in full.
Orthokeratology (Ortho-K)
Ortho-K is the use of specially designed rigid contact lenses worn overnight. The contact lens gently reshapes the cornea giving clear vision the following day without contact lenses or glasses. The effect of the lenses is temporary, giving a day of clear vision and lenses need to be worn every night. (If the lenses are not worn at night, vision will be blurred again the next day).
Overnight Ortho-K lenses produce a corneal shape that seems to be ideal for preventing axial length progression. Ortho-K makes use of “reverse geometry” lenses that are relatively flat in the center. Wearing these lenses at night causes the cornea to become temporarily flat centrally and a little steeper in the mid-periphery. As a result, the Ortho-K produces focused central and mid-peripheral images, which is useful for myopia control.
Although RGP lenses are not known for being comfortable, Ortho-K lenses are worn only at night when sleeping, so there is no discomfort from lens-lid interaction. These are large lenses that don’t move on the eye and provoke sensation. In addition, the materials used are highly oxygen permeable.
Ortho-K is very satisfying for the practitioner. For many children, getting out of glasses gives a big boost to self-esteem; and their parents are thankful to be doing something positive for their children by reducing their myopic progression. Among kids who are active, Ortho-K is safer than glasses for contact sports and safer than ordinary contact lenses for swimmers. Myopia control is just one of many positive benefits of Ortho-K.
