Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study

NCT03191942 | Completed DMC

• 1 other identifier: HSEARS20170118004
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 2

Brief Summary

This project aims to study the effects of treatment characteristics on myopia control in orthokeratology by investigating the effects of modified treatment zone by reducing the lens back optic zone diameter on the effect of myopia control. The project will be a two-year randomized, double-masked (examiner - mask axial length only) study conducted at The Hong Kong Polytechnic University recruiting sixty Chinese subjects aged between 6-11. Subjects will be randomly assigned to two ortho-k groups. The Control group will wear KATT BeFree lens with a BOZD of 6mm while the Test group will wear KATT MC lens with a modified BOZD of 5mm.

Conditions

Myopia

Keywords

Myopia control; Orthokeratology; Children; Treatment zone

Outcome Measures

Primary Outcomes (1)

• Change in axial length before and after two years of lens wear

  To determine the change in axial length measured at baseline and two years after lens wear using IOLMaster

  2 years

Secondary Outcomes (3)

• Treatment zone characteristics

  2 years

• Pupil sizes

  2 years

• Choroidal thickness

  2 years

Study Arms (2)

Modified ortho-k lenses

EXPERIMENTAL

Participants wearing ortho-k lens with a modified BOZD of 5mm

Device: Modified ortho-k lenses

Ortho-k lenses

ACTIVE COMPARATOR

Participants wearing ortho-k lens with a standardized BOZD of 6mm

Device: Ortho-k lenses

Interventions

Modified ortho-k lenses DEVICE

KETT MC lens

Modified ortho-k lenses

Ortho-k lenses DEVICE

KATT BeFree lens

Ortho-k lenses

Eligibility Criteria

• Age: 6 Years - 11 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Manifest myopia between 1.00-4.00D in both eyes at screening visit
• Manifest astigmatism ≤2.50D; with-the-rule astigmatism (axes 180 ± 30)
• D; astigmatism with other axes ≤0.50D in both eyes at screening visit
• \<1.00D difference in manifest spherical equivalent (SE) between the two eyes at screening visit
• Baseline cycloplegic objective refraction between 1.00-4.00D in sphere; astigmatism ≤2.50D; \<1.00D difference in manifest SE between the two eyes
• Best-corrected logMAR visual acuity 0.10 or better in both eyes Symmetrical corneal topography with corneal toricity \<2.00D in either eye
• Normal ocular health other than myopia
• Agree to be randomized and to attend the scheduled visits and aftercare

You may not qualify if:

• Contraindications to atropine: known allergies or cardiovascular disease, epilepsy
• Contraindications to contact lens wear and ortho-k: corneal scar, history of ocular inflammation/infection, limbus-to-limbus corneal cylinder and dislocated corneal apex
• Strabismus or amblyopia
• History of myopia control treatment (e.g. soft contact lenses, progressive add spectacles, atropine eye drops)
• Rigid contact lens (including ortho-k) wear experience
• Systemic condition which might affect refractive development (for example, Down syndrome, Marfan's syndrome)
• Ocular conditions which might affect refractive error (for example, cataract, ptosis)
• Poor response to lens wear including poor lens handling, poor vision and/ocular response after lens modifications
• Poor compliance with schedule visits

Sponsors & Collaborators

• The Hong Kong Polytechnic University: lead

Study Sites (2)

School of Optometry, The Hong Kong Polytechnic University

Kowloon, Hong Kong

Location

School of Optometry

Kowloon, Hong Kong

Location

Related Publications (7)

• Owens H, Garner LF, Craig JP, Gamble G. Posterior corneal changes with orthokeratology. Optom Vis Sci. 2004 Jun;81(6):421-6. doi: 10.1097/01.opx.0000135097.99877.5d.

  PMID: 15201715 BACKGROUND

• Lu F, Simpson T, Sorbara L, Fonn D. The relationship between the treatment zone diameter and visual, optical and subjective performance in Corneal Refractive Therapy lens wearers. Ophthalmic Physiol Opt. 2007 Nov;27(6):568-78. doi: 10.1111/j.1475-1313.2007.00520.x.

  PMID: 17956362 BACKGROUND

• Gifford P, Swarbrick HA. The effect of treatment zone diameter in hyperopic orthokeratology. Ophthalmic Physiol Opt. 2009 Nov;29(6):584-92. doi: 10.1111/j.1475-1313.2009.00672.x. Epub 2009 Aug 3.

  PMID: 19663928 BACKGROUND

• Tahhan N, Du Toit R, Papas E, Chung H, La Hood D, Holden AB. Comparison of reverse-geometry lens designs for overnight orthokeratology. Optom Vis Sci. 2003 Dec;80(12):796-804. doi: 10.1097/00006324-200312000-00009.

  PMID: 14688542 BACKGROUND

• Sridharan R, Swarbrick H. Corneal response to short-term orthokeratology lens wear. Optom Vis Sci. 2003 Mar;80(3):200-6. doi: 10.1097/00006324-200303000-00009.

  PMID: 12637831 BACKGROUND

• Munnerlyn CR, Koons SJ, Marshall J. Photorefractive keratectomy: a technique for laser refractive surgery. J Cataract Refract Surg. 1988 Jan;14(1):46-52. doi: 10.1016/s0886-3350(88)80063-4.

  PMID: 3339547 BACKGROUND

• Guo B, Cho P, Cheung SW, Kojima R, Vincent S. Optical changes and association with axial elongation in children wearing orthokeratology lenses of different back optic zone diameter. Eye Vis (Lond). 2023 Jul 1;10(1):25. doi: 10.1186/s40662-023-00344-3.

  PMID: 37391828 DERIVED

MeSH Terms

Conditions

Myopia

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases

Study Officials

• Pauline Cho, phd

  The Hong Kong Polytechnic University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: June 14, 2017
• First Posted: June 19, 2017
• Study Start: June 20, 2017
• Primary Completion: March 21, 2021
• Study Completion: July 27, 2021
• Last Updated: July 20, 2022

Record last verified: 2022-07

Locations

HK (2)