September 1, 2021
By Dean Psarakis, B.Optom., Senior Research Optometrist, Brien Holden Vision Institute
Understanding what is to be expected in terms of visual quality reduction as a practitioner is critical in the guidance we can provide to our patients.
With a growing body of evidence supporting the effectiveness of optical devices in the management of myopia, the popularity of such interventions is on the rise. These devices include myopia management spectacle lenses, myopia management multifocal soft contact lenses, orthokeratology (OrthoK) lenses, and to a lesser extent, bifocal and progressive addition spectacles. Evidence on the efficacy of the above-mentioned interventions is extensive and ranges from approximately 30% to 60% (reduction in axial length elongation).1–5 However, the impact of these interventions on visual performance is less widely reported. Although it is generally regarded that optical strategies used to manage myopia impact visual performance, there is little guidance for practitioners on measuring and assessing visual quality with these devices.
Visual Quality with Devices Prescribed in Myopia Management
Currently, some research points to certain metrics that may be useful in measuring the loss of visual quality using myopia management devices.
High Contrast Visual Acuity (HCVA)
When viewing through the portion of the spectacle lens with the myopia control features (for example, off-axis or peripheral gaze viewing through the lenslets), a reduction in high contrast visual acuity (HCVA) is expected with the use of myopia management lenses. This drop in HCVA ranges from three to five letters on the Snellen chart and depends on the specific design.6 A similar reduction in HCVA was also observed with the use of myopia management/multifocal contact lenses and found to be approximately a one-line reduction.7–9 In comparison, high contrast VA with OrthoK is thought to be comparable to that seen with single vision spectacles,10 with less than one letter reduction in VA observed over eight hours.11
Low Contrast Visual Acuity (LCVA)
Compared to single vision lenses, a greater decrement in low contrast visual acuity (LCVA) is observed with myopia management lenses. LCVA is compromised in myopia management/multifocal contact lenses by a similar if not slightly higher magnitude of approximately five to six letters, or around one line.12–14 Unlike HCVA, LCVA is reduced in OrthoK, once again in the order of approximately one line, mainly due to the increase in higher order aberrations induced by the flattening of the cornea.15–17 It should be noted that lens designs that incorporate higher add power, greater variation in power profile across the optical zone, and decentered lenses may result in a greater decrement in visual performance. Furthermore, pupil variations (as occurs in low light conditions) also impact VA.
Contrast Sensitivity
Contrast sensitivity has been shown to be reduced with myopia management spectacle lenses, particularly across higher spatial frequency ranges.6,18 Similarly, multifocal contact lenses have been shown to reduce contrast sensitivity compared to single focus contact lenses. Garcia-Marquez et al. found a reduction from 55 dB to 28 dB at the spatial frequency of 3 cpd.19 OrthoK treatment has also been shown to reduce contrast sensitivity from 1.45 log units pre-treatment to 1.29 log units post-treatment in a study by Hiraoka et al.20
Subjective Assessment of Vision Quality
Objective metrics such as visual acuity and contrast sensitivity have been shown to have little to no correlation with subjective visual satisfaction.13,21 This underscores the importance of exploring the quality of vision from the patient’s perspective and not relying on visual acuity alone as a predictor of satisfaction. Such questions may explore the overall comfort of vision, central vision, peripheral vision, daytime, and night vision.21
Guidance for Clinical Practice
Up until now, high contrast visual acuity alone has represented the extent of recommended assessment regarding visual quality in myopia management. Based on the evidence, additional measurements can add sensitivity and relevance in gauging the day-to-day quality of vision that patients may experience. The following table is a summary of a suggested list of measures that may inform the quality of vision patients can experience along with the approximate expected reduction according to the device used:
Suggested List of Measurements to Inform the Quality of Vision According to Myopia Management (MM) Device Used
Measurement | MM Spectacles compared to single vision spectacles | MM/Multifocal Contact lenses compared to single vision contact lenses | Orthokeratology compared to best corrected pre-treatment |
High Contrast Visual Acuity | up to 1 line reduction | 1 line reduction | none |
Low Contrast Visual Acuity | 1 line reduction | 1 line reduction | 1 line reduction |
Contrast Sensitivity | decreased for higher spatial frequencies | decreased for higher spatial frequencies | decreased for higher spatial frequencies |
Subjective Assessment | possibly poorer:
|
possibly poorer:
|
possibly poorer:
|
Considerations at Follow-Up Visits
A six-month review is widely recognized as the gold standard for myopia management patients.22,23 The above measures should be reassessed regularly to monitor the quality of vision experienced by patients. It is important to keep in mind that changes in visual quality at subsequent follow-up visits may not solely be the result of the unwanted side effects of a particular myopia management device (particularly with multifocal spectacle and contact lenses), but they might be influenced by other factors, such as myopia progression, changes in binocular visual function, and even ocular health considerations, such as dry eye. Implementing the above assessments in routine assessments will help a more rapid diagnosis of the underlying reason for the decrement in visual performance. It will also help in educating the parents and/or the child on expected visual performance. When it comes to visual quality, it is also worth noting that some research suggests that the patient’s age may impact visual adaptation, with younger age groups demonstrating greater adaptive abilities.24,25 Therefore, closer monitoring and/or reinforcement of visual performance may be needed in older age groups.
Take-Home Message
Understanding what is to be expected in terms of visual quality reduction as a practitioner is critical in the guidance we can provide to our patients. Establishing what is to be anticipated and relaying this to our patients may improve compliance and ultimately result in better myopia management outcomes.
Dean Psarakis is an Australian optometrist who has completed his Masters in International Health at the Vrij University in Amsterdam, The Netherlands. He has a keen passion for working within indigenous populations and in lower income settings globally. Dr. Psarakis is currently pursuing a career in vision research with BHVI.
References
- Huang J, Wen D, Wang Q, McAlinden C, Flitcroft I, Chen H, et al. Efficacy Comparison of 16 Interventions for Myopia Control in Children: A Network Meta-analysis. Ophthalmology [Internet]. 2016 Apr [cited 2021 Aug 20];123(4):697–708. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26826749
- VanderVeen DK, Kraker RT, Pineles SL, Hutchinson AK, Wilson LB, Galvin JA, et al. Use of Orthokeratology for the Prevention of Myopic Progression in Children: A Report by the American Academy of Ophthalmology. Ophthalmology [Internet]. 2019 [cited 2021 Aug 20];126(4):623–36. Available from: http://www.ncbi.nlm.nih.gov/pubmed/30476518
- 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 [Internet]. 2019 [cited 2021 Aug 20];96(8):556–67. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31343513
- Lam CSY, Tang WC, Tse DY-Y, Lee RPK, Chun RKM, Hasegawa K, et al. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol [Internet]. 2020 [cited 2021 Aug 20];104(3):363–8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31142465
- Bao J, Yang A, Huang Y, Li X, Pan Y, Ding C, et al. One-year myopia control efficacy of spectacle lenses with aspherical lenslets. Br J Ophthalmol [Internet]. 2021 Apr 2 [cited 2021 Aug 20]; Available from: http://www.ncbi.nlm.nih.gov/pubmed/33811039
- Li X, Ding C, Li Y, Lim EW, Gao Y, Fermigier B, et al. Influence of Lenslet Configuration on Short-Term Visual Performance in Myopia Control Spectacle Lenses. Front Neurosci [Internet]. 2021 May 25 [cited 2021 Aug 18];15:505. Available from: https://www.frontiersin.org/articles/10.3389/fnins.2021.667329/full
- Fernández J, Rodríguez-Vallejo M, Martínez J, Burguera N, Piñero DP. Prediction of Visual Acuity and Contrast Sensitivity From Optical Simulations With Multifocal Intraocular Lenses. J Refract Surg [Internet]. 2019 Dec 1 [cited 2021 Aug 20];35(12):789–95. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31830295
- Gong CR, Troilo D, Richdale K. Accommodation and Phoria in Children Wearing Multifocal Contact Lenses. Optom Vis Sci [Internet]. 2017 [cited 2021 Aug 18];94(3):353–60. Available from: http://www.ncbi.nlm.nih.gov/pubmed/28027276
- Madrid-Costa D, Tomás E, Ferrer-Blasco T, García-Lázaro S, Montés-Micó R. Visual performance of a multifocal toric soft contact lens. Optom Vis Sci [Internet]. 2012 Nov [cited 2021 Aug 20];89(11):1627–35. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23034336
- Sorbara L, Fonn D, Simpson T, Lu F, Kort R. Reduction of myopia from corneal refractive therapy. Optom Vis Sci [Internet]. 2005 Jun [cited 2021 Aug 20];82(6):512–8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15976589
- Nichols JJ, Marsich MM, Nguyen M, Barr JT, Bullimore MA. Overnight orthokeratology. Optom Vis Sci [Internet]. 2000 May [cited 2021 Aug 25];77(5):252–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/10831215
- Diec J, Tilia D, Thomas V, Bakaraju RC. Predicting Short-Term Subjective Vision Performance of Contact Lenses Used in Myopia Control. Eye Contact Lens [Internet]. 2018 Sep [cited 2021 Aug 20];44(5):308–15. Available from: http://www.ncbi.nlm.nih.gov/pubmed/29210828
- García‐Marqués JV, Macedo‐De‐Araújo RJ, Cerviño A, García‐Lázaro S, McAlinden C, González‐Méijome JM. Comparison of short‐term light disturbance, optical and visual performance outcomes between a myopia control contact lens and a single‐vision contact lens. Ophthalmic Physiol Opt [Internet]. 2020 Nov 4 [cited 2021 Aug 20];40(6):718–27. Available from: https://onlinelibrary.wiley.com/doi/10.1111/opo.12729
- Kang P, McAlinden C, Wildsoet CF. Effects of multifocal soft contact lenses used to slow myopia progression on quality of vision in young adults. Acta Ophthalmol [Internet]. 2017 Feb [cited 2021 Aug 20];95(1):e43–53. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27495880
- Berntsen DA, Barr JT, Mitchell GL. The effect of overnight contact lens corneal reshaping on higher-order aberrations and best-corrected visual acuity. Optom Vis Sci [Internet]. 2005 Jun [cited 2021 Aug 20];82(6):490–7. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15976586
- Nti AN, David OD, Berntsen A. Optical changes and visual performance with orthokeratology C L I N I C A L A N D E X P E R I M E N T A L. 2019 [cited 2021 Aug 20]; Available from: https://sci-hub.se/10.1111/cxo.12947
- Gifford K. Binocular visual function in orthokeratology contact lens wear for myopia [Internet]. [cited 2021 Aug 18]. Available from: https://eprints.qut.edu.au/116154/1/Kate_Gifford_Thesis.pdf
- Jaskulski M, Singh NK, Bradley A, Kollbaum PS. Optical and imaging properties of a novel multi-segment spectacle lens designed to slow myopia progression. 2020 [cited 2021 Aug 20]; Available from: https://doi.org/10.1111/opo.12725
- Vicente Garc ıa-Marqu es J, Juliana Macedo-De-Ara ujo R, Cervi A, Garc ıa-L azaro S, McAlinden C, Manuel Gonz alez-M eijome J. Comparison of short-term light disturbance, optical and visual performance outcomes between a myopia control contact lens and a single-vision contact lens. Ophthalmic Physiol Opt [Internet]. 2020 [cited 2021 Aug 19]; Available from: https://sci-hub.se/10.1111/opo.12729
- Hiraoka T, Okamoto C, Ishii Y, Kakita T, Oshika T. Contrast Sensitivity Function and Ocular Higher-Order Aberrations following Overnight Orthokeratology. Investig Opthalmology Vis Sci [Internet]. 2007 Feb 1 [cited 2021 Aug 20];48(2):550. Available from: http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.06-0914
- Ghorbani-Mojarrad N, Cargill C, Collard S, Terry L. Patient experience and physiological response to two commercially available daily disposable myopia control contact lenses. Contact Lens Anterior Eye [Internet]. 2021 Feb 19 [cited 2021 Aug 18];101426. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1367048421000266
- Gifford KL, Richdale K, Kang P, Aller TA, Lam CS, Liu YM, et al. IMI – Clinical Management Guidelines Report. Investig Opthalmology Vis Sci [Internet]. 2019 Feb 1 [cited 2021 Aug 18];60(3):M184. Available from: http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.18-25977
- Wolffsohn JS, Flitcroft DI, Gifford KL, Jong M, Jones L, Klaver CCW, et al. IMI – Myopia Control Reports Overview and Introduction. Investig Opthalmology Vis Sci [Internet]. 2019 Feb 28 [cited 2021 Aug 18];60(3):M1. Available from: http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.18-25980
- Chang C-F, Cheng H-C. Effect of Orthokeratology Lens on Contrast Sensitivity Function and High-Order Aberrations in Children and Adults. Eye Contact Lens [Internet]. 2020 Nov [cited 2021 Aug 20];46(6):375–80. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31577565
- Lu Y, Lin Z, Wen L, Gao W, Pan L, Li X, et al. The Adaptation and Acceptance of Defocus Incorporated Multiple Segment Lens for Chinese Children. Am J Ophthalmol [Internet]. 2020 [cited 2021 Aug 20];211:207–16. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31837317