The Space Vision app gets children to tap increasing faint black and white squares on a grey background to make aliens pop up and make a noise.
Their ability to keep track of the squares can be used to screen for vision problems and developers hope it will ease the burden on the NHS.
The co-founder of Vision Games, said it was an "exciting prospect".
Luke Anderson started the company with Dr Stephanie Campbell with support from the Centre of Excellence in Mobile and Emerging Technologies at the University of South Wales.
Early tests picked up vision problems, such as lazy eye, in children as young as two.
Mr Anderson said: "We're living in a time where there's increased pressure on the health service and if you can get patients monitoring their own vision at home that takes stress off hospital systems."
The app, once publically available, would initially flag up any vision problems it identified to the user and advise them if they needed to make an appointment with a GP or optician.
In the long-run, Mr Anderson said the data could be synced with family GPs so doctors could access the information to make an assessment.
Mr Anderson, a consultant eye surgeon at Cwm Taf University Health Board, said the idea came from the "extremely difficult" experience of trying to assess children's eyesight using charts.
They often struggled to get young children to sit still, so developing a game children would take an interest in helps them gather more data.
Areas of vision tested include colour, motion, black on white and differentiating between shades of grey.
The app is about to undergo larger clinical tests after a small initial run, but Mr Anderson said if everything went to plan, it could be downloadable within 18 months.
Mr Anderson said getting children to sit still "was still a problem," adding: "But, looking at my children, the time when they're quiet is when they're sitting there on a tablet or a phone.
"So we just naturally took the science and tried to implement it on that platform. The use of technology for efficiency within the NHS is an exciting prospect."

Judge Madeline Haikala threw out the case against Eric Parker after his two previous trials ended in hung juries.
CCTV footage last year showed a confrontation between 57-year-old Sureshbhai Patel and two officers in an Alabama suburb.
Mr Patel was thrown to the ground, an incident which he says left him partially paralysed.
In her 92-page opinion District Judge Haikala said evidence presented during Madison police officer Eric Parker's two trials did not eliminate the reasonable doubt that the policeman was guilty of a crime.
"The court has no reason to expect a different result in a subsequent trial given the totality of the evidence that the parties have provided," Ms Haikala wrote.
The footage from police cameras last February shows Mr Patel - who speaks no English - trying to walk away from the officers, who eventually shove him to the ground.
Mr Parker had told jurors that Mr Patel's actions and appearance were "in sequence'" with those of a burglar.
He said Mr Patel tried walking away and wouldn't answer questions when officers approached him, and that he was suspicious when the man reached for his pockets and when he pulled one of his hands free during a pat-down.
Mr Patel had recently arrived in the US to help care for his grandson, who was born prematurely, when the incident took place.
He was walking outside his son's home when police said they received a call from a neighbour about a suspicious person.
According to the civil rights complaint filed in court, Mr Patel told the police officers who stopped him "no English, Indian", and gave his son's house number.
A police officer then threw him abruptly to the ground, injuring him seriously, the complaint said.
In an exclusive interview with the BBC in November 2015, Mr Patel's son Chirag told the BBC that things had been difficult for his Dad since the incident. "Slowly he's making progress and getting independence. But still he's not 100% and we don't know if he's going to get 100%."
But he added that while he wanted justice his family would accept whatever decision the judge made. He said his view of America has not changed.
"It was a land of opportunity, and it still is a land of opportunity. America has changed my life in a positive way. So my views are not changed because of this one incident with my Dad."
A game for tablets is being developed in Wales which parents can use to test their children's eyesight at home.
[NEXT_CONCEPT]
A federal judge in the US has acquitted a policeman who was charged over a serious assault on an Indian man.