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Mrs Areej Okashah 

Research Topics and Related Projects:

Electronic low vision aids have been available for people with low vision for some time. Table mounted electronic low vision aids (commonly known as CCTVs) have existed for many years. Subject reading speed and duration have been found to be significantly greater with the CCTV systems than with optical devices. However, their high price, lack of flexibility and portability limited their use. Head mounted devices have also been available but the benefits of these over traditional devices (e.g. optical magnifiers) have not been demonstrated, however younger patients and those with better distance vision are more likely to benefit from them. User feedback has been found to be essential to understand the benefits and shortcomings of electronic devices.

Portable electronic low vision aids (PELVAs) have advantages over other electronic devices and optical low vision aids, such as portability, lower cost, ease of use, flexible focus, variable magnification, larger field of view, and contrast adjustment.

As the cost of electronic devices is reducing and the cost of optical magnifiers is increasing, the Compact+ (a PELVA) has now become a prescribing option for people with visual impairment in the NHS, Low Vision Service Wales (LVSW). With the current pace of technological development, it is likely that electronic low vision aids will be used by many people with macular disease, especially when conventional optical low vision aids are no longer sufficient to meet their requirements.

The larger PELVAs are used principally for reading. There is a large amount of literature on reading performance among people with low vision. Factors such as age, visual acuity, ocular condition, contrast sensitivity, scotoma size, field of view, reading text characteristics and type of low vision aid have all been found to affect reading performance and/or ability.

As yet, no studies have evaluated reading performance with PELVAs, and no literature is available to help us understand which factors (e.g. visual functions or device parameters) would affect reading performance among people with visual impairment using these devices. Therefore, whilst low vision practitioners have evidence based guidance to assist in the selection and prescribing of optical devices in NHS low vision services, no such guidance exists for PELVAs. 

We are currently 1) investigating the parameters in commercially available PELVAs such as magnification and contrast 2)  looking for the prescription pattern of these devices among visually impaired 3) evaluating the use and satisfaction of PELVAs compared to the optical devices 4) investigating which factor(s) (visual functions and/or device parameters) affect reading performance in people with age related macular degeneration who are using PELVAs and to inform those who prescribe or choose PELVAs which functions or attributes are most important.



Scholarship (2012-2015) from Jordan University of Science & Technology; towards PhD in Optometry and Vision Sciences. 

Scholarship (2008-2009) from Jordan University of Science & Technology; towards MSc in Optometry.


Research Team:       

Prof. Rachel North(Lead Supervisor)

Dr. Barbara Ryan (Supervisor)

Dr. Jennifer Acton (Collaborator)

Dr. Ivan Wood (Collaborator)

Dr. Rebecca Jones (Collaborator)