communication mediumPhD Thesis
There are at least 2.2 billion people affected by vision impairments worldwide, and the number of people suffering from common eye diseases like cataracts, diabetic retinopathy, glaucoma or macular degeneration, which show a higher prevalence with age, is expected to rise in the years to come, due to factors like aging of the population.
Medical publications, ophthalmologists and patients can give some insight into the effects of vision impairments, but for people with normal eyesight (even medical personnel) it is often hard to grasp how certain eye diseases can affect perception. We need to understand and quantify the effects of vision impairments on perception, to design cities, buildings, or lighting systems that are accessible for people with vision impairments.Conducting studies on vision impairments in the real world is challenging, because it requires a large number of participants with exactly the same type of impairment. Such a sample group is often hard or even impossible to find, since not every symptom can be assessed precisely and the same eye disease can be experienced very differently between affected people.
In this thesis, we address these issues by presenting a system and a methodology to simulate vision impairments, such as refractive errors, cataracts, cornea disease, and age-related macular degeneration in virtual reality (VR) and augmented reality (AR),which allows us to conduct user studies in VR or AR with people with healthy eyesight and graphically simulated vision impairments. We present a calibration technique that allows us to calibrate individual simulated symptoms to the same level of severity for every user, taking hardware constraints as well as vision capabilities of users into account.
We measured the influence of simulated reduced visual acuity on maximum recognition distances of signage in a VR study and showed that current international standards and norms do not sufficiently consider people with vision impairments. In a second study,featuring our medically based cataract simulations in VR, we found that different lighting systems can positively or negatively affect the perception of people with cataracts. We improved and extended our cataract simulation to video–see-through AR and evaluated and adjusted each simulated symptom together with cataract patients in a pilot study, showing the flexibility and potential of our approach. In future work we plan to include further vision impairments and open source our software, so it can be used for architects and lighting designers to test their designs for accessibility, for training of medical personnel, and to increase empathy for people with vision impairments. This way, we hope to contribute to making this world more inclusive for everyone.