Peripheral Refraction in Myopic Patients After Orthokeratology

Abstract

CRT inverts the pattern of peripheral refraction in spherical equivalent refraction, creating a treatment area of myopic reduction within the central 25 degrees of visual field, and a myopic shift beyond the 25 degrees. In peripheral refraction for 30 degrees and 35 degrees, the amount of myopia induced in terms of spherical equivalent has an almost 1:1 relationship with the amount of baseline spherical equivalent refraction to be corrected.

Binocular Visual Function in Orthokeratology Contact Lens Wear for Myopia

“…There was no significant loss of central refractive treatment at 12 months despite the appearance of such, particularly in children but acuity with SCLs compared to OK acuity was better than 0.00 logMAR (6/6 or 20/20) throughout. (Table 4.2) Similar apparent on-axis undercorrection by autorefractor measurement after OK treatment has been noted, (Queiros et al 2010, Kang and Swarbrick 2011, Zhong et al 2015 and this likely indicates two things. Firstly, the excellent OK acuity found in this study would indicate that full treatment was achieved.…”

“…Clinically insignificant changes are made to astigmatism components of refraction, and this effect is symmetrical around the visual axis. (Charman et al 2006, Kang and Swarbrick 2010, Queiros et al 2010 Alteration of the overall peripheral refraction profile is noted after just one night of wear, and is maintained after 14 days of wear. (Charman et al 2006) After one month of wear, young adult myopes (n=28, mean age 24 years)…”

“…(Queiros et al 2010) After three months of wear in 10 children aged 11 to 16 years, less hyperopia was noted in the nasal peripheral visual field from 20 degrees, and from 30 degrees in the temporal visual field. No alteration to peripheral optics was noted in a contralateral RGP wearing eye in the same study.…”

“…Charman et al (2006) found that J0 became more myopic after 14 days of adult OK wear, and Queiros et al The role of RPR in myopia progression and control is uncertain, and the link between RPR changes in OK and its myopia control effect has not been investigated. RPR changes due to OK, though, have been found after one week of OK wear (Charman et al 2006) with the longest study of RPR changes in adults being just over one month (Queiros et al 2010) and three months in children. ( …”

“…Swarbrick 2010, Queiros et al 2010) Children (mean age 9.6 years) and young adults (mean age 24.6 years) demonstrate an equal and increased response to OK treatment than older adults (mean age 43.9 years) after one hour of open-eye OK wear. (Jayakumar and Swarbrick 2005) Both myopic children and young adults demonstrate a reversal and maintenance of relative peripheral hyperopia with OK wear; (Charman et al 2006, Kang and Swarbrick 2010, Queiros et al 2010 these groups can be considered equally susceptible to the beneficial effect of this optical alteration.…”