Discontinuation of Lens Wear in New Ortho-k Children (DOEE2)

Condition(s) targeted: Myopia

Intervention: single-vision glasses (Device); ortho-k lenses (Device)

Phase: N/A

Status: Active, not recruiting

Sponsored by: The Hong Kong Polytechnic University

Official(s) and/or principal investigator(s):
Pauline Cho, PhD, Principal Investigator, Affiliation: The Hong Kong Polytechnic University

This study aims at investigating the efficacy of myopic control using ortho-k in younger and older children.

Official title: Discontinuation of Orthokeratology on Eyeball Elongation (DOEE) Study. (2) Discontinuation of Lens Wear in New Ortho-k Children

Study design: Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Treatment

Primary outcome: Axial length

Secondary outcome: Incidence of adverse effects

Detailed description: Children wearing ortho-k have been shown to have slower rate of myopic progression than those wearing single-vision spectacles (Cho et al. 2005) or soft lenses (Walline et al. 2009). Younger myopic children (aged 6-10 years old) may have the faster increase in myopia than old myopic children (aged 11-15 years old), i. e. the rate of myopic progression may be different in different age groups and in children with different refractive status (Edwards 1999; Fan et al. 2004; Cheng et al. 2007). Although the refractive correction with ortho-k has been well documented, it is unknown whether the efficiency and reversibility of ortho-k for myopic reduction as well as myopic control are similar in children of different age and refractive groups. In this 14-month study, the eyeball length in 45 younger (6-10 years old) and 45 older (11-15 years old) myopic children before and after ortho-k will be evaluated. Eyeball elongation will be determined for the first 7 months when single-vision glasses will be prescribed (Phase I) and the next 7 months when ortho-k will be prescribed (Phase I). Rate of myopic progression will be determined and compared between the two groups of children in the two phases.

Minimum age: 6 Years. Maximum age: 15 Years. Gender(s): Both.

Criteria:

Inclusion Criteria:

- Age: between 6 to 15 years old

- Myopia: between 1. 50D and 4. 50D in at least one eye

- Spherical equivalent (SE): between -1. 00D to -4. 50D in both eyes

- Astigmatism: ≤ 3. 00D of axes 180 +/- 30 or ≤ 1. 00D of other axes; and the amount is

less than refractive sphere

- Anisometropia: ≤ 1. 50D in both refractive sphere, refractive cylinder and SE

- Best corrected monocular visual acuity: equal to or better than 0. 10 in logMAR scale

in both eyes

- Willingness to wear contact lenses or spectacles on a daily basis

- Can obtain good ortho-k results with the study lenses

- Availability for follow-up for at least 14 months

Exclusion Criteria:

- Strabismus at distance or near

- Contraindication for contact lens wear and ortho-k (e. g. limbus to limbus corneal

cylinder and dislocated corneal apex

- Systemic or ocular conditions which may affect contact lens wear (e. g. allergy and

medication)

- Systemic or ocular conditions which may affect refractive development (e. g. Down

syndrome, ptosis)

- Prior experience with the use of rigid lenses (including ortho-k)

- Prior experience with myopia control treatment (e. g. refractive therapy or

progressive spectacles)

- Non-compliance to the follow up schedule

- Non-compliance to the use of the prescribed optical correction

- Poor ocular response to ortho-k lens wear

- Significant residual refractive error after ortho-k treatment resulting in poor

unaided vision (worse than 0. 18 in logMAR scale)

School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong, China

Related publications:

Cheng D, Schmid KL, Woo GC. Myopia prevalence in Chinese-Canadian children in an optometric practice. Optom Vis Sci. 2007 Jan;84(1):21-32.

Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Curr Eye Res. 2005 Jan;30(1):71-80.

Edwards MH. The development of myopia in Hong Kong children between the ages of 7 and 12 years: a five-year longitudinal study. Ophthalmic Physiol Opt. 1999 Jul;19(4):286-94.

Fan DS, Lam DS, Lam RF, Lau JT, Chong KS, Cheung EY, Lai RY, Chew SJ. Prevalence, incidence, and progression of myopia of school children in Hong Kong. Invest Ophthalmol Vis Sci. 2004 Apr;45(4):1071-5.

Walline JJ, Jones LA, Sinnott LT. Corneal reshaping and myopia progression. Br J Ophthalmol. 2009 Sep;93(9):1181-5. doi: 10.1136/bjo.2008.151365. Epub 2009 May 4.

Starting date: October 2010
Last updated: July 10, 2013