I'm very sorry to hear about what you're going through.
I'm not too privy with employment/disability regulations in the US, however in the UK, with the appropriate and verified documentation (such as doctor/hospital/opthomologist notes), an employer must accommodate the needs and requirements of any contracted employee if they have any type of disability.
In the UK, eye strain, specifically if it causes severe symptoms, distress and negatively impacts work productivity, can be logged as a recognised disability.
If the employer is not able to accommodate to their employees requirements, an option is for an employee to make a proposal, such as being able to undertake any contracted work using alternative equipment (which can be provided by the employer or personally purchased by an employee).
I have personally interacted with a few individuals over the years that have experienced similar issues in terms of work related eye strain and digital equipment. Some of their employers have been very considerate and helpful (by allowing individals to use work based laptops and computers connected to alternative digital displays etc) and others not so much. However I would imagine any employer affiliated closely within a government regulated industry would need to strictly abide by all disability and employment regulations thoroughly, and offer appropriate resolutions alongside any privacy or data related matters and concerns that they may have.
Taking this into account, it may be worth exploring all employement and disability regulations (if you haven't already done so) within your district, and if your employer becomes difficult during any process of discussion, it'd be worth seeking professional legal advice.
