Anstice 2011.

Study characteristics
Methods	Study design: paired‐eye, cross‐over RCT Study center: 1 Number randomized: 40 children Study follow‐up: 20 months (10 months for each period) Exclusions and losses to follow‐up: no exclusions; 5 (12.5%) and 6 (15.0%) were lost to follow‐up at 10‐month visit and 20‐month visit, respectively
Participants	Age: mean = 13.4 years (range 11 to 14 years) Gender: 11 boys, 29 girls Culture: New Zealand, including East Asian ethnicity and others (European, Indian, and Maori/Pacifica) Inclusion criteria: (1) 11 to 14 years old at recruitment; (2) spherical equivalent between ‐1.25 and ‐4.50 D in the least myopic eye as determined by noncycloplegic subjective refraction; (3) myopia progression ≥ 0.50 D in the previous 12 months; (4) best‐corrected spectacle visual acuity of Snellen 6/6 or better in each eye; (5) willingness to wear contact lenses for ≥ 8 hours per day during the study Exclusion criteria: history of (1) astigmatism ≥ 1.25 D; (2) anisometropia ≥ 1.00 D; (3) strabismus at distance or near as assessed by cover test; (4) ocular or systemic pathology likely to affect refractive development or successful contact lens wear; (5) birth weight ≤ 1250 g
Interventions	Group 1 (n = 21): 10 months wearing 2.00 D dual‐focus (DF) contact lens in the dominant eye and SVSCL in the contralateral eye, followed by 10 months wearing the swapped lens assignment  Group 2 (n = 19): 10 months wearing DF contact lens in the nondominant eye and SVSCL in the contralateral eye, followed by 10 months wearing the swapped lens assignment
Outcomes	Primary outcome: Change in spherical equivalent refraction measured by cycloplegic autorefraction Secondary outcome: Change in axial eye length measured by partial coherence interferometry Measurements taken at baseline and every 5 months for 20 months Unit of analysis: data analyzed by dominant eye
Notes	Study dates: 2005 to not reported Trial registration: ACTRN12605000633684 Funding source: Maurice and Phyllis Paykel Trust; New Zealand Optometric and Vision Research Foundation; Cornea and Contact Lens Society of New Zealand Notes: study is also known as the Dual‐focus Inhibition of Myopia Evaluation in New Zealand (DIMENZ) study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Children were randomized into group 1 or group 2 using a permuted block design with a block size of 4"
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not reported
Masking of participants (performance bias)	High risk	"The participants and the optometrist responsible for clinical care were not masked to lens assignment"
Masking of outcome assessors (detection bias) Progression of myopia	Low risk	The "investigating optometrists responsible for making outcome measures were masked"
Masking of outcome assessors (detection bias) Secondary outcomes	Low risk	The "investigating optometrists responsible for making outcome measures were masked"
Masking of data analyzers	Unclear risk	This was not reported
Incomplete outcome data (attrition bias) Incomplete outcome(s) data	Low risk	Six participants (15%)—3 from each group—were lost to follow­up and were excluded from the analysis: 4 children due to difficulties handling the contact lenses, 1 due to negative publicity on contact lens solutions, and 1 due to dislike of cycloplegia
Selective reporting (reporting bias)	Low risk	All outcomes specified prospectively on a clinical trials registry were reported
Other bias	High risk	One of the study authors disclosed an inventor patent for the contact lens design. Data were not appropriately analyzed for paired‐eye nor cross‐over design