Table 1.

Summary table of relevant studies across different species where negative lens wear was interrupted with periods of darkness, periods of free viewing or periods of positive lens wear.

Reference	Species	Degree of Imposed Defocus	Type of Interruption	Interruption Duration	Visual experience during the interruption	Study outcome
Schmid and Wildsoet 1996	Chicken	Monocular −10D, +10D or plano lens	Lens removed	1 × 11, 9, 6, 3 or 0 hrs/day	Unrestricted vision	Interrupting lens wear with periods of normal vision is more effective at reducing lens-induced myopia than at reducing lens-induced hyperopia.
Winawer and Wallman 2002	Chicken	Monocular −6D or +6D lens	Kept in the dark wearing lenses	Five dark periods: 1. 7 × 30 mins/day every 2 hrs 2. 58 mins/hour every hour 3. 13.5 hrs/day 4. 13.75 hrs/day 5. 4 × 30 mins/day	Kept in the dark with lenses on	Three main findings: 1. Several brief daily interrupting episodes are more effective than a single or a few longer daily ones. 2. Extremely brief episodes are ineffective. 3. When positive and negative lenses are worn successively, the positive lens has the dominant effect, even if the negative lens is worn five times longer.
Norton et al. 2006	Tree Shrew	Monocular −5D lens	Lens removed and substituted for −5D, −3D, plano, +3, +4, +5, +6, or +10D	1 × 45 mins/day	Controlled distance in lab room with refractive monitoring	High degrees of myopic defocus (>5D) cannot compete with lens-induced myopia. Low degrees myopic defocus effectively reduced lens-induced myopia only in some eyes.
Kee et al. 2007	Rhesus monkey	Binocularly −3D lens	Lens removed and substituted for plano or +4.5D	4 × 15 mins/day	Not mentioned in the paper	Brief periods of unrestricted vision prevented lens-induced myopia. Brief periods of viewing through +4.5D lenses produced weaker protective effects.
McBrien et al. 2012	Tree Shrew	Binocular −9.50D	Lens removed and substituted for plano or +4D	1 × 1 hr/day or 2 × 30 mins/day	Unrestricted vision in an open-mesh cage	Interrupting negative lens wear with 1 hr of positive lens wear was more effective in preventing the development of experimentally induced myopia than interrupting using a plano lens
Leotta et al. 2013	Guinea Pigs	Monocular −4D or −5D lens	Kept in the dark wearing lenses or lens removed	Dark period 1 × 0.25, 1, 2, 4 or 6 hrs/day Lens removed 1 × 5 mins, 15 mins, 30 mins, 1 hr, 3 hr, 6 hr, 9 hr/day	Kept in the dark with lenses on or Unrestricted vision with lenses removed in an open lab environment	Lens-induced myopia develops after brief exposures to hyperopic defocus and is very long lasting without competing signals. The induced myopia rapidly decays if interrupted by one 30 min period/day of ‘normal viewing’.