UK Prime Minister Boris Johnson has been accused of inventing a new Covid-19 symptom on the fly while defending the recent actions of his senior political advisor.

For those not familiar with the unfolding story, let's recap. On Friday, May 22, two British newspapers, The Daily Mirror and The Guardian, revealed that Dominic Cummings – Johnson's chief political advisor, who has been in attendance at the government's scientific advisory meetings on how to deal with the pandemic – had reportedly broken the UK's lockdown rules, which had of course been instigated by the Prime Minister. They alleged that shortly after Dominic Cummings was seen legging it out of No. 10 Downing Street, London on March 27, he and his family drove 420 kilometers (260 miles), a 5-hour journey, to his parents' house in Durham, north-east England to seek childcare while his wife was exhibiting Covid-19 symptoms. Mr Cummings himself developed coronavirus symptoms while there.

This was somewhat in contravention of the rules the government had set out for the UK, which at the time was to not leave your house under any circumstances except to exercise once a day or to buy essential items such as food or medicine, and to self-isolate at home for 14 days if you or your family experienced any Covid-19 symptoms. 

Investigations by The Mirror and Guardian then revealed that Cummings and his family were spotted out on what would later be revealed as his wife's birthday 48 kilometers (30 miles) away from they where they had been isolating, at Barnard Castle, a popular tourist destination a 45-minute drive away. It appeared he'd broken quarantine whilst breaking quarantine.

It has caused somewhat of a furor in the UK, as the revelations of his breaking the very lockdown measures imposed on the British public by the government did not lead to his resignation, or condemnation of his actions by the government, but instead an outpouring of support led by the Prime Minister himself. This led to the public accusing the government of a "one rule for them, one rule for us" message that undermined how one could "interpret" the lockdown measures.

In an unprecedented turn of events, Mr Cummings, a behind-the-scenes aide, held a press conference in the 10 Downing Street Rose Garden in which, under a grilling from journalists, he insisted he had acted as a concerned parent who was seeking childcare while both he and his wife suffered from the virus, and thus acted within reason and the law. Many journalist rightfully pointed out many parents across the UK would have liked to seek childcare while suffering the symptoms of the virus but were under the impression the government's lockdown rules impeded that. 

One particular aspect of the press briefing had eyebrows raised in confusion. When asked about the day trip to Barnard Castle with his family, Cummings explained he was testing his eyesight to ensure he was safe to drive back to London.

As everyone has pointed out, strapping your kid into your car and driving for half an hour isn't a classic eye exam. "STRAP IN AND HOLD ON TIGHT KIDS, DADDY'S CHECKING HIS EYESIGHT, YEEEEEEHAWWWWWW," just doesn't sound like a better option than popping to opticians.

It's even prompted – and I honestly can't believe I'm typing this sentence – warnings from the police that you shouldn't use a car to test your ability to see.

Cummings' actions have put the government in an awkward position, given that they appear committed to defending his actions on taking the trip. 

Boris Johnson again showed his support during the UK's daily coronavirus press conference last night, when he appeared to suggest failing eyesight and a need to wear glasses was a symptom of Covid-19.

Johnson, who was hospitalized with Covid-19 in early April, told reporters he was “finding that I have to wear spectacles for the first time in years, because I think of the likely effects of this thing – so I’m inclined to think there’s some... I think that’s very, very plausible that eyesight can be a problem associated with coronavirus.”

The Prime Minister has been accused of inventing new symptoms to explain his aide's actions.

Poor vision has not been listed as a symptom of Covid-19 by the US Centers for Disease Control and Prevention (CDC), or the World Health Organization (WHO). Conjunctivitis is listed as a less common symptom by the WHO. A large study on hospitalized patients published in the BMJ last week found that fewer than 1 percent of patients experienced the symptom, making it the least-experienced symptom of the disease that we are aware of.

Conjunctivitis usually doesn't cause any interference with eyesight, but can make your eyes uncomfortable and water, BBC News reports. But if it gets in front of your pupil, it can cause blurry vision. So it's possible Cummings did have a very rare case of blurry vision from Covid-19 but we don't recommend driving (with your entire family in the car) as an eye exam. 

However, if Johnson is suggesting he is still experiencing Covid-related vision loss to the point that he needs his glasses this long after returning to work (he tested negative for Covid-19 on April 13 following his own bout of the illness), that is a cause for concern.

Maybe Johnson is ahead of the curve on this, but it's somewhat surprising from a government that took 5 weeks to impose a lockdown, and only listed the loss of taste and smell as a symptom last week.