Saturday, March 15, 2014

Understanding How A Vision Screener Works

By Jaclyn Hurley


Pediatric vision testing is normally recommended with the intention of detecting disorders early enough. The common disorders include amblyopia, misaligned eyes (strabismus) and refractive errors that may call for eye glasses. The most commonly used approaches include community settings such as schools, health fairs, or in medical institutions. Vision screener is the most important medical device that has made this form of testing so cheaply and easily accessible.

With solid scientific background and support from several studies and testimonials published in medical journals, this is a device that has gain favor with several medical professionals, government agencies and non-governmental organizations alike. Currently, it is used by nurses in schools, pediatricians, opticians, members of the Lions club and many other professionals. The only required compliance is the camera fixation and there is a specially designed sound to achieve by provoking fixation.

Among several other features, the vision screening device gives results with proven accuracy and screens both eye balls simultaneously. In addition to this, the screening is done at a distance of one meter away (3.3 feet) from the camera. It lasts for only 0.8 second and displays results automatically on the screen. This makes it very easy to use and interpret the results that can also be stored in a data base for later reference through the various documentation options available.

This means that even non-medical staff can actually perform the screening. The person to perform screening starts by pulling the camera trigger to start; this is followed by a sound that is meant to attract attention. The image of both eyes is captured on a white triangle on the screen that then allows for performing the necessary measurements. The recommended screening distance is one meter (3.3 feet) from the camera. The tolerance level is +-5 centimeters or +-2 inches. The results are then displayed on the screen in a matter of seconds.

In order to come up with results, the measurements performed include determination of refraction size, pupil size and the corneal reflexes. These are then compared to referral criteria that are age based. For anisometropia, refractions of both eyes are compared while corneal irregularity is determined for astigmatism.

In order to diagnose myopia, the nearsightedness is checked and farsightedness checked for hyperopia. The other checks that are done include comparison of pupil sizes for both eyes for anisocoria and determination of symmetric eye alignment for corneal reflexes. All these happen automatically in seconds hence the immediate results displayed on the screen.

A PASS displayed on the screen implies that all readings are within the recommended limit meaning that none of the conditions has been detected. In case of one or more of measurements or not within the limit, the result displayed is a REFER. Either a REFER or PASS is displayed on the screen as soon as the measurement is complete.

These results can be saved as the device has an internal database. These can be displayed later on and for many patients in a chronological order helping in data manipulation and other uses. It eliminates the need for visiting an optician when unnecessary yet ensures that you have opportunity to seek help at the earliest sign of eye condition problem.




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