The Immediate Effect of Defocus Spectacles On the Choroid Thickness Using Optical Coherence Tomography on Children

The Immediate Effect of Defocus Incorporated Multiple Segment Spectacle Lenses (DIMS) on the Choroid Thickness Using Swept Source-Optical Coherence Tomography (SS-OCT) on Children.

The purpose is to examine temporary changes in the subfoveal choroid thickness after removal and after resumed use of Defocus Incorporated Multiple Segment Spectacle Lenses (DIMS).

Inclusion Criteria:

• Myopic children using Defocus Incorporated Multiple Segment Spectacle Lenses (DIMS) from the ongoing randomized clinical non-inferiority study: "Defocus Incorporated Multiple Segment (DIMS) Spectacle Lenses versus Orthokeratology lenses (OKL) for slowing myopia progression in children aged 6-12 years. A non-inferiority randomized clinical trial. The NISDO study" (ClinicalTrials.gov Identifier NCT05134935).
• Myopia at the time of inclusion in the NISDO study (inclusive): -2.00 to -4.75 D spherical component and up to -2.50 D of regular astigmatism (both eyes).
• Anisometropia at the time of inclusion in the NISDO study ≤ 1.50 D cycloplegic spherical equivalent refractive error.
• Best corrected visual acuity (inclusive) at the time of inclusion in the NISDO study: 0.8 Snellen (equivalent to ≥ 3/5 letter on the 0.8 line = 78 ETDRS letters).

Exclusion Criteria:

• Manifest or intermittent squint.
• Contraindications to the use of OKL comprising (not exhaustive): keratoconus, chronic allergic conjunctivitis, and keratoconjunctivitis sicca.
• Previous eye surgery.
• Chronic eye disease demanding daily use of eye drops.
• Non-compliance to eye examinations (unstable fixation or anxiety towards contact lenses).
• Previous myopia control treatment.