The Department for Transport has put drivers' vision proposals on the backburner to focus on driving regulations for diabetics instead.
A debate at Westminster last week confirmed government plans to reduce the number plate testing distance will not be revisited until the House of Commons returns from recess in October.
Parliamentary under-secretary of state for transport Mike Penning said diabetes would lead the agenda before then because the other two parts of the proposals on medical requirements for drivers - on eyesight and on epilepsy - were more complicated.
The Optical Confederation said it would meet Penning to discuss visual requirements and raise concerns about the delay in the government's response to a DVLA consultation on the matter.
The diabetes debate was led by Caithness, Sutherland and Easter Ross MP John Thurso, who told of a diabetic constituent having his licence removed in 'curious circumstances', having previously been cleared to drive with the same condition.
Penning said: 'I will be subject to criticism from those involved in the other areas on which we are not yet ready to introduce proposals.
'My view, however, is that if we are ready to introduce proposals in one of those areas - by October we should have a proposal on diabetes - we should go ahead and remove the blight that affects not only the honourable gentleman's constituent but many other people around the country.'
Government plans to relax vision standards for car and motorcycle drivers in the UK were announced in February despite calls for more stringent testing by optical bodies and road safety groups. This was followed by a consultation period that ended in April.
Speaking on behalf of the Optical Confederation, Mark Nevin said: 'Similar issues were raised in the debate on driving and diabetes that would equally apply to vision, in particular a lack of clear rules and systems to ensure all drivers meet the medical requirements to drive safely.
'We advocate that drivers should be guided by professionals to make informed choices about medical conditions that affect their driving. Drivers should not be left to make this difficult judgement alone.
'The minister also noted complexities with respect to vision and driving and we thank him for giving this issue due consideration.'
The latest update follows a previous parliamentary debate (News 24.06.11) about whether the number plate test remained an effective screening tool.