Children with a significant amount of astigmatism may present unique challenges for clinicians who provide myopia control treatment. Andrew Pucker, OD, of the University of Alabama’s School of Optometry, addresses these patients’ needs through a hypothetical case report and discusses the role of soft, toric, multifocal lenses in slowing myopia progression.
Visit 1: Baseline Visit
Franklin, a 13-year-old boy, reports to your clinic for a myopia management evaluation. After performing an initial history, you learn that he is an active athlete who plays baseball and football. Franklin informs you that he has been using single vision, daily disposable contact lenses (CLs) for more than 6 years and, despite being happy with them, he often feels as though his vision is blurry. He notes that he does not have the same vision problem while wearing spectacles. He does not complain of other issues related to his CLs and appears to wear them responsibly. Franklin’s father mentions that he had a case of viral optic neuritis approximately 2 years prior, which has permanently decreased the vision of his left eye. You do not note any other pertinent findings during the clinical history portion of the exam, and no other ocular findings were uncovered in the case file, so you perform your standard myopia management evaluation and obtain the values listed below (Table 1).
After reviewing the data, you speak with Franklin and his father about high myopia and describe its clinical characteristics, which include a refractive error worse than -6.00 diopters (D) or an axial length greater than 26.5 mm, according to the American Academy for Pediatric Ophthalmology and Strabismus1 Franklin possesses both of these characteristics. You also explain that any level of myopia increases a patient’s risk of retinal detachment, cataracts, or glaucoma.2 Although these conditions are more likely to happen during adulthood, you educate them on the warning signs of each condition and stress the need to report to the clinic immediately if Franklin notices signs of retinal detachment, which include flashes of light or a sudden onset of floaters.
Now that you have identified high myopia and its associated risk factors, you are ready to discuss some potential myopia management treatments. You indicate that Franklin may be a candidate for soft, toric, multifocal CLs or low dose atropine. And since Franklin is happy wearing CLs, you suggest the former as the most suitable treatment option. You ease any concerns about CL blurriness by telling Franklin that the reason he sees better with his glasses is because they correct his astigmatism — something his non-toric contact lenses fail to address. They agree to move forward with your treatment suggestion, and you order him quarterly replacement, custom silicone hydrogel CLs (Table 2). These lenses will allow correction of his high myopia and astigmatism while using a center-distance multifocal design — a technique that, researchers say, can help slow the progression of myopia.3 You request a +2.50 add for each CL because, according to the peripheral defocus theory, higher add powers may result in better myopia management, while add powers higher than this may result in visual disturbance.4 After outlining your treatment plan, you schedule Franklin for a CL dispense visit in 2 weeks — enough time for the trial CLs to arrive. You make sure to place your CL order by contacting a consultant before leaving the office for the day.
Visit 2: Dispense Visit
Franklin reports on schedule for his CL dispense visit. After allowing 15 minutes for the lenses to settle, you verify that they have good coverage, centration, and movement. When asked about his vision, Franklin states that it is variable and fuzzy. You perform a visual acuity assessment and refraction over his CLs and obtain the data listed below (Table 3). You determine that you need to order a new set of CLs to correct for the significant over-refraction. Since his CLs appear to fit well and he lives far away, you agree to send the new lenses directly to his home and schedule him for a 1-month follow-up visit.
After finishing with patients for the day, you call the lab to obtain guidance on ordering a new set of CLs for Franklin. Your conversation with the lab leads you to believe that the visual fuzziness Franklin described is likely the result of an optic zone that is too small. Discrepancies between your over refraction and Franklin’s spectacle prescription confirm your suspicions. While most multifocal CLs are worn by patients with presbyopia who have small pupils, the 2.00 mm standard optic zone of the CLs you ordered may not be optimal for younger patients with larger pupils. In fact, soft CLs used for myopia management frequently have optic zones larger than 3.00 mm.5 You proceed to order CLs with the same parameters while adjusting the optic zone (Table 4).
Visit 3: 1-Month Follow-Up
Franklin and his father report again after wearing the replacement CLs for about 2 weeks. Franklin indicates that he is happy with the comfort of his CLs, yet again he is unhappy with his vision. He specifically notes that his vision was better with the single vision CLs he wore prior to initiating treatment. Once again, you evaluate his visual acuity, obtaining the parameters noted below (Table 5). You also confirm that his CLs fit well. Your myopic over-refraction, in conjunction with Franklin’s visual symptoms, leads you to question whether his add power is too high.
Considering some recent research, you opt to try CLs with a +2.00 add and advise Franklin that he can either keep wearing his current CLs or temporarily switch back to his single vision CLs while he waits for the new lenses to arrive (Table 6).6,7 Meanwhile, you schedule Franklin for a 1-month follow-up.
Visit 4: 2-Month Follow-Up
Franklin and his father return for the CL follow up visit, but this time Franklin reports that he is happy with his vision, and when asked, he indicates that he would not change anything about his CLs. You evaluate his visual acuity and CLs, finalize his prescription, and recommend a 6-month myopia management evaluation (Table 7).
Long-Term Follow Up Visits
Despite your 6-month recommendation, Franklin and his father elect to return annually due to the significant amount of driving involved with visiting your clinic. During each of these annual exams conducted over the next 3 years, you perform a standard evaluation and obtain the refractive error and axial length data noted below (Table 8). Over the course of 3 years, Franklin’s eyes undergo an axial length increase of 0.48 mm (mean, 0.16 mm/year) and 0.54 (mean, 0.18 mm/year) in his right and left eyes, respectively. This change in axial length occurred while his refractive error was relatively stable, and it was roughly on par with how much axial length would progress in patients of a similar age with emmetropia.9
astigmatism and are willing to adopt a trial and error approach across multiple visits,
they may succeed in slowing myopia progression.
Franklin’s axial length is growing in proportion to the rest of his eye and the treatment is effectively managing his refractive error progression. He is still undergoing treatment with soft toric multifocal CLs and overall, he appears to be happy with his treatment.
One important point to note with Franklin’s case is that he presented with clinically meaningful astigmatism while wearing single vision spherical CLs. While it may save chair time to prescribe spherical equivalent CLs to patients with astigmatism, poor vision is a top reason patients discontinue CL wear.8 And with custom and standard soft CLs readily available in astigmatic or multifocal powers or a combination of the 2, clinicians can easily meet most patient’s refractive error needs. Research suggests that undercorrecting patients with myopia may even slightly accelerate myopia progression.3 But when clinicians take the time to evaluate the needs of patients with high myopia and astigmatism and are willing to adopt a trial and error approach across multiple visits, they may succeed in slowing myopia progression.
- Progressive (High) Myopia. American Association for Pediatric Ophthalmology and Strabismus. Accessed October 19, 2022. https://aapos.org/glossary/progressive-high-myopia
- Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res. 2012;31(6):622-660. doi:10.1016/j.preteyeres.2012.06.004
- Walline JJ, Lindsley KB, Vedula SS, Cotter SA, Mutti DO, Twelker JD. Interventions to slow progression of myopia in children. Cochrane Database Syst Rev. 2011;(12):CD004916. doi:10.1002/14651858.CD004916.pub3
- Bickle KM, Mitchell GL, Walline JJ. Visual performance with spherical and multifocal contact lenses in a pediatric population. Optom Vis Sci. 2021;98(5):483-489. doi:10.1097/OPX.0000000000001695
- Savla K, Pucker AD, De Gracia P. Effect of pupil size on peripheral defocus caused MiSight contact lens optics at different retinal eccentricities. American Academy of Optometry. 2022;E-Abstract 225402.
- Chamberlain P, Peixoto-de-Matos SC, Logan NS, Ngo C, Jones D, Young G. A 3-year randomized clinical trial of MiSight lenses for myopia control. Optom Vis Sci. 2019;96(8):556-567. doi:10.1097/OPX.0000000000001410
- Walline JJ, Walker MK, Mutti DO, et al. Effect of high add power, medium add power, or single-vision contact lenses on myopia progression in children: the BLINK randomized clinical trial. JAMA. 2020;324(6):571-580. doi:10.1001/jama.2020.10834
- Pucker AD, Tichenor AA. A review of contact lens dropout. Clin Optom (Auckl). 2020;12:85-94. doi:10.2147/OPTO.S198637
- Wong YL, Yuan Y, Ding Y, et al. Percentile Charts for Normal Axial Length Changes in Chinese Schoolchildren with Stable Emmetropia. Investing Ophthalmol Vis Sci. 2021;62(8):2323.