The Safety and Effectiveness of Breath-O Lenses

In Hong Kong, approximately 80% of children are myopic by the end of childhood. There is intense interest currently in the potential role of peripheral defocus as a clinical treatment to slow myopia progression. One of the most successful treatments for myopia is orthokeratology. Currently, Breath-O correct lenses are new designed ready-made orthokeratology lenses. This study is to evaluate the safety of wearing this new orthokeratology lens and the effectiveness of clinical performance in young adult.

Short-sightedness (myopia) is the most common refractive error in the world. In Hong Kong, approximately 80% of children are myopic by the end of childhood. Current treatment strategies to control (i.e. slow) myopia progression in children are primarily designed to harness the natural "emmetropization" process, in which visual feedback from retinal image clarity regulates the rate of eye growth. There is intense interest currently in the potential role of peripheral defocus as a clinical treatment to slow myopia progression, not least since this approach permits clear central vision. One of the most successful treatments for myopia is orthokeratology, which is a therapy of using custom-made rigid gas permeable contact lens. The special design of this contact lens can reshape the corneal profile to minimize the central refractive error while producing beneficial peripheral defocus. Currently, Breath-O correct lenses are new designed ready-made orthokeratology lenses which are made of new material with more elasticity as compared traditional lens material. This study is to evaluate the safety of wearing this new orthokeratology lens and the effectiveness of clinical performance in young adult.

Breath-O correct lenses are new designed ready-made orthokeratology lenses which are made of new material with more elasticity as compared traditional lens material

measured by OCULUS Keratograph® 5M and graded by JENVIS redness grading system It is a scale of 0 to 4, the higher the score, the more redness the ocular surface manifests

The best corrected visual acuity was measured in LogMAR (Snellen 20/20 vision = 0.00 in LogMAR ; each readable letter add -0.02 to the score, the smaller the number i.e. more negative, the better visual acuity)

Refractive errors were determined by subjective refraction for treatment group (Breath-O correct lens wearer), the outcome was represented as mean spherical equivalent refraction with unit in diopter (SER, = 1/2 Cylindrical power + spherical power)

Inclusion Criteria: Refractive error: Spherical: normally -1.00D to -4.00D (maximum up to -5.00D); Cylindrical: normally half of Sph (against-the-rule Astigmatism.: lower than -0.75D) (maximum up to -1.50D) Best corrected Visual acuity: monocular ETDRS 0.0 or better Ocular health: No ocular abnormality, no contra-indications for overnight orthokeratology lens wear, no refractive surgery General health: No systemic diseases Requirement: No history of orthokeratology lens wearing. Agree to participate in this study and willing to wear the orthokeratology lenses overnight in accordance with the instructions given and to come back for follow up within the study period