Preferably a room with low lighting, with no light focused directly on the device. Every direct light source should be hidden from the device and should not be visible as a reflection in the patient’s eyes. The space should preferably have no laterally open windows.
No, unless it is in a specially-screed gazebo.
The only condition needed for measurement is that the subject is at the correct distance from the device. 2WIN can measure patients sitting, standing or lying down, as the software automatically corrects any inclination of the head.
2WIN is a binocular refractometer that works at 1 m from the patient’s eyes in normal vision conditions. It therefore measures refraction in both eyes at the same time. The binocular function of the device makes it more relaxing, non-irritating and non-invasive for the patient during testing. 2WIN measurement is based on eccentric photorefraction. This technique uses infrared light projected across the patient’s pupils onto the retina. Depending on the refractive error, the reflected light forms a specific increase in luminosity inside the pupil. The spherical reaction is calculated according to the intensity of this increase.
No, the two devices have two different approaches (2win is binocular, measures at 1m distance, in more physiologically normal conditions and allows for accommodation).
No, subjectivity through a phoropter or test glasses is always required. However, 2WIN allows simultaneous binocular refraction during observation in a free space, avoiding the tube effect and also allowing objective measurement.
No, 2WIN cannot measure refraction when it is connected to a PC via USB. All network services can, however, be used.
Via files and activation codes received by e-mail to transfer easily to the device’s memory card, in a guided step-by-step process.
Of course, any MicroSD card can be used to save 2WIN data.
Yes. 2WIN is a device that can be connected to EMR and management software as data from 2WIN is in XML format.
No, only from the catalogue printer on a strip. However, it can be used with any traditional office printer, via PC or MAC, on standard paper, thanks to PDF files produced by the device.
Battery life is not an autonomous variable; it depends on many factors linked to the device’s use. In particular, battery life may vary if WI-FI is used or not, if LEDs and attention sounds are used and according to environmental lighting.
When the device is on, the monitor reduces luminosity after 30 seconds of inactivity and then turns off after another 30 seconds.
2WIN goes into standby mode after 1 minute if WI-FI mode is on and after 10 minutes in normal mode. After 10 mins of standby, the device turns on, emits an acoustic signal and displays a message saying that it will shut down automatically in 30 seconds.
Standby before automatic shutdown can be customized.
Please note that the rechargeable battery must be charged at least once every 30 days.
Measurements are easier with intermediate pupil dimensions (around 5 mm). 2WIN emits infrared rays all over the eye. When pupil aperture is too small it cannot measure refraction while, on the contrary, when pupil aperture is too large, measurements may be invalidated by aberrations of the corneal periphery.
Yes. Under the same conditions measurements should remain within the device’s precision range (precision of measurement for spherical/cylindrical defect: +/- 0.25 D, precision of measurement for cylindrical axis: +/- 5 degree). Variables that influence conditions are those relating to the surrounding environment. A change in luminosity influences the aperture of the pupil. Changes in pupil size can create aberrations that alter ocular refraction.
The human optical system is another extremely important variable and is continually changing. A person may have different refraction in the morning and in the evening, including diopters of difference.
Measuring at a distance of 1m, accommodation certainly plays a part.
This will clearly be more evident in children than in adults.
2WIN has only a slight accommodation stimulus, leading to partial accommodation in children (the ‘fast’ kind that is normally not corrected with glasses). In adults it is so slight that it can be ignored.
Yes. It is better not to wait for the pupil to dilate completely in order to avoid the diameter of the pupil being excessive, leading to aberrations or preventing measurements being taken.
The device will not give a result and will only signal a level of myopia or hypermetropia that is too high. Using test lenses and over-refraction, you can obtain refraction through a difference of values.
Accommodation can be reduced by taking a second measurement in the subject, asking them to focus on a target 3-5m behind the operator. As long as the subject’s gaze is near 2win, the operator can ‘detect’ the pupil and obtain a refractive value with a non-accommodating eye.
Of course, if you make sure – in the case of glasses – to incline the lenses downwards to avoid a double reflection. There is no problem with contact lenses.
Of course, as long as pupil movement is not excessive and the subject is not clearly cross-eyed.
Depending on the degree of opacity of the crystalline lens, the device may give a degree of reliability that is higher or lower, or may not give any result at all.
No. You must take monocular measurements, focussing one eye at a time and covering the other and by endeavouring to get the patient to look towards the centre of 2WIN.
Of course – in monocular mode.