Motivation: Uncorrected refractive errors are the main cause of visual impairment worldwide. Hundreds of millions of people suffer from uncorrected refractive errors. The great majority of this population live in low resource settings. This, however, has been proved to not be caused by difficult access to treatment, as eyeglasses are a very cost-effective treatment and the majority of all visual impairment can be treated in some way, but due to a diagnosis barrier. This is to say, there are very few professionals which can correctly diagnose these errors.
This is where the QuickSee comes in. PlenOptika Inc. (USA), in collaboration with the ‘Universidad Autónoma de Madrid’, developed the QuickSee as a solution to the global health problem caused by uncorrected refractive errors. The QuickSee is a low-cost autorefractor designed with simplicity in mind to allow personnel with minimal training to obtain an eyeglass prescription. In a few seconds, it can accurately measure existing refractive errors, thus facilitating eye care access to lower resource settings and closing the diagnosis gap.
Problem: The QuickSee is currently being fully commercialized throughout the globe. It has proved to be very useful in easing access to eyecare, as well as streamlining the process to achieve an eyeglass prescription. However, feedback received from users have shown that the refraction process may be further ‘automated’ or optimized. If subjective refraction were to be incorporated in the same step as objective refraction.

Refractive errors are very common eye disorders in which the eye cannot clearly focus on images. If they are not diagnosed in time, especially during childhood, they may result in severe visual impairment and even blindness. Refractive errors can be corrected simply by wearing glasses, an effective and inexpensive remedy whose cost does not exceed $5 in developing countries. Even so, refractive errors are currently one of the major global health problems. The main cause of this situation is the shortage of eye care professionals and automated equipment capable of prescribing glasses. PlenOptika proposes as a solution the QuickSee, a low cost and easy to use autorefractor. This device improves the efficiency and scope of eyecare professionals to prescribe glasses, while enabling people with minimal training in refractive techniques such as nurses, technicians or even non-healthcare personnel to carry out measurements of refractive errors quickly and reliably.

This Bachelor Thesis presents the development of a calibration system for a visual simulation device: the SimVis. This system prescribes multifocal lenses allowing patients to know if they adapt correctly to their needs before surgical implantation. To approach the project, the functionality of the calibration system has been divided into three main modules: camera, communication, and image processing, which are finally integrated into a main program. In addition, a calibration cradle prototype has been built to perform verification and validation tests.

Motivation: Worldwide, it is estimated that more than 1 billion people do not have the eyeglasses they need. This problem is especially prevalent in developing countries due to the lack of an appropriate infrastructure for eyecare deployment and eyecare professionals capable of providing eyeglass prescriptions. The procedure for obtaining these prescriptions consist of using an objective measurement of the refractive power of the eye, which is usually very accurate but can fail in several cases, followed by a subjective refinement which is performed by an eyecare professional based on the feedback of the patient. If the initial objective measurement is not accurate, it can greatly complicate the procedure increasing the time required to refract the patient and thus the bandwidth of the eyecare professionals.