Birte Höft

Birte Höft

Master's Thesis

Implementing an augmented reality application to improve stereoscopic vision


Wolfgang Mehringer (M. Sc.), Prof. Dr. Björn Eskofier, Veronika Ringgold (M. Sc.), Prof. Dr. Georg Michelson


02 / 2023 – 08 / 2023


More than 1.3 billion people in the world suffer from eye diseases. One of the most common visual impairments is amblyopia with a global estimated prevalence of 1.36% [1]. It is a developmental eye disorder, which occurs in early childhood. The disorder is manifesting itself by not processing the information coming from the eyes equally. As a result, the healthier eye may be favored by the brain, resulting in one-sided vision. This can lead to a limited performance of the visual depth perception or even a total loss of stereopsis [2–5].

Over the last 250 years, a common therapy has been to cover the healthy eye with a patch to train the suppressed eye [2, 6]. The treatment duration of the eye patch method can usually take up to 6 months, which is one of the disadvantages. Furthermore, the patched person might be psychologically distressed, uncomfortable in wearing the patches, and limited in their vision. This results in low compliance for this treatment method [2, 3].

Recent research has shown that binocular treatment is promising, e.g., possible treatment options are 3D video games or 3D footage [7]. The results showed that visual acuity, spatial awareness, and stereopsis were improved [7, 8]. Applications in Virtual Reality (VR) represent a more contemporary solution. Multiple factors improve the compliance of patients, including a shorter application time of 30 minutes per day and the aspect of gamification. In VR applications, the tasks are primarily split between the eyes. The application’s background is visible to both eyes, but the visibility of various game elements differs between the eyes. While both eyes must cooperate to complete the task, their dissociation due to the monocular perspective of the various task components leaves stereopsis mostly unaddressed [9–11].

It is now possible to specifically treat stereopsis using the application described by Mehringer and colleagues [12]. They created an application that resembles a real-life scenario, which shows a dynamic ball game. During the game, both eyes always perceive the same content. The game consists of a ball dropping from the ceiling onto an inclined plate. As soon as it strikes the plate, the ball is split into two balls and they move in the user’s direction. One ball appears closer to the user. Since monocular depth cues are disabled, the user requires both eyes to extract the depth information. The aim of the application is to hit the closest ball with a racket [12].

However, the application in VR could become monotonous over time if it is played for 30 minutes each day. The prerequisites for a successful VR application are a suitable game setting and the complete suppression of the real world [7]. The VR headset must be adjusted for each patient and is approved for adults only. Thus, a more realistic and entertaining system is required. The goal of this thesis is to implement an application in Augmented Reality (AR) based on the VR application by Mehringer et al. [12]. An AR system allows for the real-world environment to be seen while digital components are blended in, which can result in improved patient engagement leading to increased compliance. Furthermore, AR headsets have the advantage of being easily adaptable to changing environmental conditions. In this project the Hololens 1 (Microsoft Corporation, Redmond, Washington, USA), which can scan the surrounding environment and surfaces, is used. The Hololens does not require calibration for each patient and both displays can be controlled independently, which is useful for binocular training [8]. According to Nowak and colleagues, the participants felt more comfortable using the AR application for amblyopia therapy than the VR application. [7]. Based on implanted AR system, a study will be conducted to compare the game ability and usability of the VR and AR systems.

[1] B. Hu et al., “The global prevalence of amblyopia in children: A systematic review and meta-analysis,” Frontiers in Pediatrics, vol. 10, p. 819 998, May 4, 2022, issn: 2296-2360. doi: 10.3389/fped.2022.819998.
[2] J. M. Holmes and M. P. Clarke, “Amblyopia,” The Lancet, vol. 367, no. 9519, pp. 1343–1351, Apr. 22, 2006, issn: 0140-6736. doi: 10.1016/S0140-6736(06)68581-4.
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[4] J. Li et al., “The role of suppression in amblyopia,” Investigative Ophthalmology & Visual Science, vol. 52, no. 7, pp. 4169–4176, Jun. 10, 2011, issn: 1552-5783. doi: 10.1167/iovs.11-7233.
[5] G. K. Von Noorden and E. C. Campos, Binocular vision and ocular motility: theory and management of strabismus, 6th ed. St. Louis, Mo: Mosby, 2002, 653 pp., isbn: 978-0-323-01129-7.
[6] S. Y. Lee and S. J. Isenberg, “The relationship between stereopsis and visual acuity after occlusion therapy for amblyopia,” Ophthalmology, vol. 110, no. 11, pp. 2088–2092, Nov. 1, 2003, issn: 0161-6420. doi: 10.1016/S0161-6420(03)00865-0.
[7] A. Nowak, M. Wozniak, M. Pieprzowski, and A. Romanowski, “Towards Amblyopia Therapy Using Mixed Reality Technology,” pp. 279–282, Sep. 2018.
[8] L. Lamprogiannis et al., “A Review of Binocular Treatment for Amblyopia,” en, European Ophthalmic Review, vol. 14, no. 1, p. 34, 2020, issn: 1756-1795. doi: 10.17925/EOR.2020.14.1.34. (visited on 01/11/2023).
[9] A. J. E. Foss, “Use of video games for the treatment of amblyopia,” Current Opinion in Ophthalmology, vol. 28, no. 3, pp. 276–281, May 2017, issn: 1040-8738. doi: 10.1097/ICU.0000000000000358. (visited on 12/09/2022).
[10] S. Jayaram, J. Vance, R. Gadh, U. Jayaram, and H. Srinivasan, “Assessment of VR technology and its applications to engineering problems,” Journal of Computing and Information Science in Engineering, vol. 1, no. 1, pp. 72–83, Jan. 1, 2001, issn: 1530-9827. doi: 10.1115/1.1353846.
[11] G. Aydindogan, K. Kavakli, A. Sahin, P. Artal, and H. Uerey, “Applications of augmented reality in ophthalmology [invited],” Biomedical Optics Express, vol. 12, no. 1, pp. 511–538, Jan. 1, 2021, Publisher: Optica Publishing Group, issn: 2156-7085. doi: 10.1364/BOE.405026.
[12] W. Mehringer, M. Wirth, D. Roth, G. Michelson, and B. M. Eskofier, “Stereopsis only: Validation of a monocular depth cues reduced gamified virtual reality with reaction time measurement,” IEEE Transactions on Visualization and Computer Graphics, vol. 28, no. 5, pp. 2114–2124, May 2022, Conference Name: IEEE Transactions on Visualization and Computer Graphics, issn: 1941-0506. doi: 10.1109/TVCG.2022. 3150486.