Photoscreeners have been designed to detect risk factors for amblyopia, rather than amblyopia or structural ocular alterations [1]. Photoscreening is currently a recognized method for vision screening in children aged 3–5 years and uncooperative older children. The American Academy of Pediatrics supported the use of photoscreening in its policy statement [2, 3]. Vision screening should generally be performed several times during a child’s formative years. It should have high specificity in younger children and high sensitivity in older children [4].

Photoscreeners use a flash camera with an acute flash-to-patient lens angle of approximately one degree such that refractive errors, a risk factor for amblyopia can be detected by a light crescent encroaching on the otherwise uniform red pupil reflex; the greater the light crescent, the greater the refractive defocus [5]. Current commercially available photoscreeners use infrared light and internal computational interpretation to estimate binocular refractive error, pupil size, and pupillary distance. The advantages of the photoscreener design include instantaneous assessment and convenience for testing children.

There are currently several photoscreener available on the market, include the S12 (Plusoptix, Nurnberg, Germany), Blinq (RebiScan, Boston, MA, USA), 2WIN (Adaptica SRL, Padova, Italy) [6] and Spot (Welch Allyn, Auburn, NY, USA). Some other devices, such as the iScreen (iScreen Vision, Inc, Cordova, TN, USA) [7] and GoCheckKids (Gobiquity, Nashville, TN, USA) [8, 9], use visible light with central reading centers. The Blinq (Rebiscan, Boston, MA, USA) device screens for ocular misalignment but not refraction. The 2WIN device is a portable binocular refractometer and vision screener commonly used in pediatric eye care. Overall, the 2WIN device offers the advantages of portability, efficiency, objectivity, non-invasiveness, and comprehensive vision assessment, making it a valuable tool in pediatric eye care for screening refractive errors and assessing vision in children.

The precision of photoscreeners in assessing the magnitude of the refractive error has improved over the last two decades [10,11,12]. Some studies have even postulated that non-cycloplegic photorefraction has acceptable accuracy and advantages over cycloplegic retinoscopy [11]. Potentially, using photoscreeners to evaluate cycloplegic refraction has the potential to enhance the standard of eye care, especially in underserved and distant locations.

Agreement studies are critical for clinical decision making when selecting devices or methods to assess refractive error assessment. If non-cycloplegic and cycloplegic refractions show a high level of agreement between the 2WIN and ARK-1 devices, it instills confidence in using either device interchangeably. In contrast, inconsistent or discordant measurements between the devices may lead to variations in the refractive correction prescribed, potentially impacting visual outcomes for patients. Therefore, this study aimed to evaluate the agreement between cycloplegic and non-cycloplegic measurements obtained with the 2WIN photoscreener and the conventional ARK-1 stationary autorefractor.