Eyeworld

EW INTERNATIONAL 68 July 2017 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer 5-year follow-up study in which he compared axial length elongation in myopic children around 10 years of age receiving long-term overnight orthokeratology to age-, SER-, and axial length-matched controls who wore spectacles. 4 He found that after 5 years, there was a statistically significant difference in axial length increase between the two groups (P=.0236). Axial length grew less over time, with significant differenc- es in growth between overnight or- thokeratology patients and controls in the first 3 years but not the last 2 years. "The current 10-year retrospec- tive review showed that refraction and UCVA were significantly im- proved by ortho-k, and the im- proved levels were maintained over the study period. Myopia progres- sion during 10 years was –0.95 D on average, which is apparently small compared with natural progression of myopia in children. Ten-year use of ortho-k in myopic children showed acceptable results in both efficacy and safety. A long-term con- tinuation of ortho-k is promising in controlling myopia progression," Dr. Hiraoka said. EW References 1. Vitale S, et al. Increased prevalence of myopia in the United States between 1971–1972 and 1999–2004. Arch Ophthal- mol. 2009;127:1632–9. 2. Lin LL, et al. Epidemiologic study of ocular refraction among schoolchildren in Taiwan in 1995. Optom Vis Sci. 1999;76:275–81. 3. Pararajasegaram R. Vision 2020–the right to sight: From strategies to action. Am J Ophthal- mol. 1999;128:359–360. 4. Hiraoka T, et al. Long-term effect of overnight orthokeratology on axial length elongation in childhood myopia: A 5-year follow-up study. Invest Ophthalmol Vis Sci. 2012;53:3913–9. 5. French AN, et al. Prevalence and 5- to 6-year incidence and progression of myopia and hyperopia in Australian schoolchildren. Ophthalmology. 2013;120:1482–91. Editors' note: Dr. Hiraoka has no finan- cial interests related to his comments. Contact information Hiraoka: thiraoka@md.tsukuba.ac.jp –2.63 D to –0.5 D within 1 year and remained at this level for 10 years (P<.0001, ANOVA with Dunnett). LogMAR UCVA was 0.80 at the start of the study period and reached 0.0 within the first year and remained at that level for 10 years (P<.0001, ANOVA with Dunnett). The mean number of times of prescription lens power replacement during the study period was 2.4 ± 1.1 times (range 0 to 5). The mean strength of the first prescription lens power was –3.22 ± 1.21 D and that of the most recent lens power was –4.18 ± 1.29 D, revealing a large difference. The average difference in lens power was used to estimate my- opia progression and was calculated at –0.95 ± 0.82 D. Myopia progression over the 10-year period showed a tendency to decrease with age. The difference in power between first and final lenses was greatest at the ages of 8 to 9 years, at around –1.5 D, and tenden- tially lower by age 16 years, showing a difference of under –0.5 D. Dr. Hiraoka noted that myopia progression in this study seemed lower than that of other studies that investigated the natural progression of myopia in myopic children. In one population-based cohort study that investigated the prevalence and progression of myopia and hypero- pia in 2,760 Australian schoolchil- dren, the prevalence of myopia in- creased by 1.4% to 14.4% (P<.0001) between baseline and follow-up in the 12-year-old cohort and by 13% to 29.6% (P<.0001) in the 17-year- old cohort. The study investigators observed that myopia prevalence in the younger patient sample suggest- ed a rise in prevalence consistent with international trends. 5 In his current study, Dr. Hi- raoka confirmed the observations he made in an earlier prospective, investigated the long-term effects of overnight ortho-k on myopia pro- gression for more than 5 years," said Takahiro Hiraoka, MD, Department of Ophthalmology, Faculty of Medi- cine, University of Tsukuba, Ibaraki, Japan, who presented his study at the European Society of Cataract & Refractive Surgeons (ESCRS) Con- gress last fall. "This study showed that a 10-year continuation of or- tho-k was promising to slow myopia progression, with a tendency of myopia progression to decrease with age, and less myopic progression compared to the natural progression of myopia." Dr. Hiraoka retrospectively reviewed the medical records of all consecutive patients who began ortho-k treatment from 8 to 16 years of age and continued the treatment for 10 years at the University of Tsukuba and Kashiwa Eye Hospital, Chiba, Japan. He collected basic de- mographic data including sex, age, manifest refraction, visual acuity, and prescription lens power over the 10-year duration, and assessed the time course of changes in several parameters by analysis of variance (ANOVA). He also examined the frequency of prescription lens power replacement during the study pe- riod, and calculated the difference between the first and latest prescrip- tion lens powers, which was consid- ered as an estimated value of myopia progression. A total of 104 eyes of 53 pa- tients fulfilled the inclusion criteria. At baseline, the mean age of the study participants was 11.5 ± 2.2 years, SER was –2.63 ± 1.22 D, and logMAR UCVA was 0.80 ± 0.28. The analysis revealed that SER and UCVA significantly improved af- ter the start of ortho-k and remained at the improved level throughout the study period. The SER went from Study reveals sustained myopic control over a 10-year period in school children using ortho-k N earsightedness is ubiq- uitous, and evidence suggests that its numbers are rising. The prev- alence of individuals with myopia in the U.S. has been estimated at roughly 40%, almost twice as high as it was 30 years ago, 1 while in countries such as Taiwan, myopia has been reported in more than 80% of school-aged children. 2 The World Health Organization has identified myopia as one of the five leading causes of blindness and visual impairments in the world. 3 As higher degrees of myopia and longer axial lengths have been associated with an increased risk of developing retinal detachment, macular degen- eration, and glaucoma, which are associated with visual impairment and blindness, gaining control over myopic progression has thus become a priority. Orthokeratology (ortho-k) uses specialized gas permeable contact lenses that are worn at night to flat- ten and reshape the anterior corneal surface. Ortho-k lenses iatrogenically induce corneal topographic spher- icalization by exerting a constant pressure on the flat meridian and variable pressure on the steep merid- ian, which helps to correct refractive error in both adults and children with varying degrees of myopia. The effects are reversible, allowing spectacle-free vision throughout the daytime hours, with the cornea reverting back again at night. The long-term outcomes of ortho-k, however, have revealed much more enduring effects on myopic progres- sion in school-aged children under- going ortho-k for 5 years. 4 10 years on A new study investigated outcomes in school children who continued ortho-k for 10 years. It revealed significant changes in the spherical equivalent refractive error (SER) and uncorrected visual acuity (UCVA) after 1 year of ortho-k treatment, which were maintained for 10 years. "There have been no studies that Capping myopia progression with overnight orthokeratology Presentation spotlight " Ten-year use of ortho-k in myopic children showed acceptable results in both efficacy and safety. " —Takahiro Hiraoka, MD

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