A 10-YEAR-OLD FEMALE presented reporting her vision with glasses was blurry when looking at the board, while watching movies and when playing tennis. Previously, I discussed with her mother contact lens myopia control, but she didn’t think her daughter was responsible enough for contact lens wear. I also discussed the benefits of myopia control, and the benefits of contact lens wear for tennis.
Two years ago, the child was given her first spectacle prescription, –1.25D OD and –1.00D OS. Six months later, the prescription was –2.00D OU, and one year ago, it was –2.50D OU. At this visit, her manifest refraction was –3.25D OD and –3.00D OS, with 20/15 VA OU at distance and near. The child’s parents had –5.50D or more myopia OU. Now that the mother had seen the progression of myopia in her daughter and believed her to be more capable of contact lens care, she agreed to myopia control.
At this visit, I discussed three types of myopia control with the patient and her mother, including soft multifocal contact lenses, orthokeratology contact lenses and low-concentration atropine. We also talked about the combination therapy of low-concentration atropine and either contact lens modality.
While the FDA has not approved any pharmaceutical or device for myopia control, it does not limit us from prescribing something to slow the progression of nearsightedness in our patients.
Here I review these options, as I presented them to the patient.
CONSIDERATIONS FOR MYOPIA CONTROL
Center distance design soft multifocal contact lenses have been reported in the peer-reviewed literature for myopia control. (Soft lenses that offer the center distance design include Proclear Mulitfocal “D” and the Biofinity Mulitfocal “D” (both monthly lenses from CooperVision), Acuvue Oasys for Presbyopia (bi-weekly, Johnson & Johnson Vision) and Natural-Vue (daily, VTI).) Soft multifocal contact lenses may be best for children who have more than 5.00D myopia because orthokeratology contact lenses are more difficult to fit in children who have myopia greater than that. Soft multifocal contact lenses may also be better for parents who wear soft contact lenses because parents know how to resolve issues.
When prescribing soft multifocal contact lenses, begin with the strongest add power because anecdotal evidence indicates that stronger add powers lead to better myopia control. This may be due to focusing some of the light further in front of the retina, thereby acting as a strong signal to slow eye growth. Most children require about –0.50D to –0.75D more minus at distance to optimize VA. If the child still exhibits suboptimal vision after incorporating the over-refraction, consider lowering the add power one step. (This should rarely be necessary, due to the requirement mentioned above.)
Orthokeratology contact lenses may be best for subjects who swim on a regular basis because the contact lenses are never worn in the swimming pool. They also may be best for parents who want to monitor their children at all times during contact lens wear because the lenses are only worn during sleep, at home.
With regard to orthokeratology contact lenses, no further consideration beyond those normally needed for optimal fitting are necessary. On average, both orthokeratology and soft multifocal contact lenses slow the progression of nearsightedness and growth of the eye by about 43%, based on reviews of myopia control studies presented in the peer-reviewed literature. Both contact lenses work equally well on average.
With low-concentration atropine, consider determining pupil size, IOP and near VA, in addition to traditional follow-up measures, simply to document the potential side effects of low-concentration atropine. Also, ask about near blur and light sensitivity at each visit. Low-concentration atropine is not commercially available, so it must be compounded by a local pharmacist. (Not all pharmacists will provide low-concentration atropine, so consult with your local pharmacist prior to offering this option to your patients.)
Although we don’t know whether low concentration atropine in conjunction with contact lenses enhances myopia control, consider prescribing the combination because the mechanisms of treatment effect a is likely to be different. Contact lenses provide myopia control through optics, and atropine provides myopia control through pharmacologic effects, although we don’t know the specific downstream effects of these two mechanisms. Having said that, few parents have shown interest in combination treatment to date, possibly because they believe the eye drops will sting or possibly because they think that the combination treatment is overwhelming to administer.
Little is known about what happens to the refractive error after discontinuation of contact lenses for myopia control. Although there is little to no evidence, the theory is that subjects should continue myopia control at least through the age during which their myopia is expected to progress, which is typically age 15 to 16 years.
Studies on low-concentration atropine show little rebound effect (subsequent increase in myopia progression) after discontinuation.
OUR TENNIS PRO
After careful consideration, the mother and daughter chose the option of soft multifocal contact lenses and concurrent use of low-concentration atropine. With –3.25D and –3.00D distance power and +2.50D add power in the right and left eyes, respectively, the contact lenses centered and moved well in each eye. However, the patient’s VA was 20/25 OU. With –0.50 and –0.75 over-refraction in the right and left eyes, respectively, the subject was able to read 20/15 OU and reported clear vision at distance and near.
We taught contact lens care and asked that the patient return in one week for a contact lens check. We also ordered low-concentration atropine to be sent to her house directly from the compounding pharmacy, but requested the patient not to administer drops until after the follow-up visit.
One week later, the patient reported clear vision and a genuine excitement about contact lens wear during tennis. She was able to insert and remove her contact lenses in less than five minutes every day. The over-refraction was plano with 20/15 VA OU. We also taught her mother how to instill eye drops, and we measured the patient’s pupils (with the room lights at maximum brightness for consistency), IOP and near VA with the contact lenses to provide baseline values before initiating administration of one drop of low-concentration atropine (to be done at bedtime in each eye). The pupils were 4.5 mm; the IOPs were 14 mmHg OU; the VA OU was 20/15 at 33 cm.
We recommended the patient make the eye drops part of the bedtime routine and to minimize potential for side effects, such as mydriasis or cycloplegia. We asked both the patient and her mother to return in one week and report whether they noticed blur while reading, or sensitivity to light.
At the return visit, the patient reported clear vision and comfortable eyes at distance and near. She said that the sun seemed particularly bright during tennis, but wearing a visor eliminated all issues. She exhibited 20/15 VA OU at distance and near; the over-refraction was plano in the right eye and –0.25D in the left, but with no improvement of VA. Her pupils were 5 mm, and her IOP was 15 mmHg OU. She exhibited Grade 4 angles by Van Herick estimation, well-centered and moving contact lenses and clear corneas.
We told the patient and her mother to return for a routine appointment in six months or sooner if they noticed blurry vision, red eyes, painful eyes or light sensitivity. Six months later, the patient reported clear vision at distance and near, with little-to-no light sensitivity. The mother reported no issues with drop instillation, and the patient exhibited 20/15 at distance and near with 4.5 mm pupils, IOPs of 13 mmHg and contact lenses that centered and moved well.
CHOOSING BY LIFESTYLE
We have learned a lot about myopia control through the past few years, but we have much yet to learn. No scientifically validated protocols are available to determine the most appropriate method for individual patients; it may be best to discuss options with the parent and the patient, and then recommend the method of myopia control that best fits their lifestyles. OM