Improving visual performance in retinitis pigmentosa by new non-invasive personalized and adaptive training.

• Applicant: Dr. Siegfried Wahl, since 7/2019
• Subject Area: Ophthalmology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 409546347

The aim of this proposal is to study the pathological visual behavior in patients with retinitis pigmentosa (RP) and to implement new methods able to improve residual visual performance. In early RP stages, peripheral vision is damaged, while central vision is relatively intact with good visual acuity. Later RP stages, however, impact central vision and acuity. Peripheral vision, despite its low resolution, is important for creating and updating an accurate representation of spatial structure for navigation and therefore RP is a condition that impairs mobility. One promising approach to recover visual performance, is to use the innate neural plasticity and provide specific eye-movement training protocol that helps patients to naturally "expand" their restricted visual field (VF). It has been shown that brain neural plasticity may involve modifications in overall cognitive strategies to successfully cope with new challenges. In a preliminary work we demonstrated the potential of neural plasticity to improve and to partially recover the patients’ visual performance during walking. We found that training the patients to perform explorative saccades to the non-seeing VF improved walking speed of patients, but other aspects of daily life, such as number of collisions with objects did not improve. This suggests that further, improved training strategies might be required to ultimately optimize navigation of RP patients in daily life. We hypothesize that to maximize transfer of training effect in real-life, exercise during training should resemble closely typical daily tasks. This could currently be achieved via virtual reality (VR) applications, with the added benefit that the patients could exercise to walk and deal with different situations without being exposed physically to the hazards of daily life. Our new protocol aims at efficient training that allows to compensate for the loss of simultaneous tracking of multiple moving targets in areas falling outside the limited functional VFs in tunnel vision: It will instruct the patients to perform in a systematic scanning pattern (SSP) fast compensatory gaze movements, in order to create a global framework of the scene and identify possible targets. Further, dynamic scanning tracking (DST) of possible targets will be practiced, which will require only one focus of attention that will cycle rapidly through the targets, will index their locations and will return to each before it moves too far away. Not in the scope of the project, but relevant is the transfer of the results to other diseases with visual field loss, e.g. hemianopia. We propose, based on our preliminary work, that neural-plasticity training may be generally applicable in a range of eye conditions with currently irreversible retinal or neuronal damage.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Dr. Iliya Ivanov, until 6/2019