The Safety and Effectiveness of Clinical Performance of Breath-O Correct Orthokeratology Lenses
Phase: NA
Conditions: Myopia, Safety Issues
Sponsor: The Hong Kong Polytechnic University

1 
 
 
Title: The safety and effectiveness of clinical 
performance of Breath-O correct orthokeratology 
lenses 
 
(NCT03616600) 
 
Date: 10th March, 2019 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Title: The safety and effectiveness of clinical performance of Breath-O correct 
orthokeratology lenses 
 
Methods: 
Sample size: 15 subjects for each group were recruited  
 
Groups:  Treatment group – prescription of Breath-O Correct lens  
 
Control group – non-contact lens wearer 
 
Inclusive criteria: 
Age: 18 to 30 years 
Refractive error: Spherical: normally -1.00D to -4.00D (maximum up to -5.00D); Cylindrical: 
normally £ half of Sph (against-the-rule Astig.: £ -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 lenses 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  
 
Parameters to be assessed: 
Effectiveness: Objective and subjective refractive error, central corneal thickness, high contrast 
visual acuity, low contrast visual acuity, corneal topography 
Safety: Corneal epithelium and endothelium health, corneal resistance factor and corneal 
hysteresis, tears quality. 
 
Subjective evaluation: OSDI Questionnaire 
 
Analysis: Categorical variables were presented as number or percentage, while continuous 
variables were presented as mean and standard deviation. Data from both eyes of each subject 
were analyzed for follow-up visits (within subjects) and for group comparison (between groups). 
RM-ANOVA, 2-way ANOVA and Friedman test were used for comparison. The significance level 
is set at p<0.05. 
 

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Protocol: 
§ 
All the subjects had a baseline eye examination with all the above tests. A written 
consent was obtained from each eligible subject before randomly allocating into 
treatment group (fitting of the contact lenses) or control group (no fitting of contact 
lens) 
§ 
A pair of Breath-O Correct lenses were prescribed for each eligible subject of the 
treatment group with full wearing instructions of orthokeratology 
§ 
After successful prescription of the lenses, the subjects of the treatment group 
came back for regular visits listed in Figure 1 
§ 
For the subjects of the control group, all had the eye examination same as those 
received by treatment group at the time point of baseline, 1st month and 3rd month. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 1. Schedule of visits 
 
 
Baseline eye examination 
+ Ortho-K lenses fitting 
Trial lens fitting visit + Delivery 
1st overnight visit 
1st week visit 
2nd week visit 
1st month visit 
2nd month visit 
3rd month visit