GLOBAL charitable foundation the Wellcome Trust has upped its stake in retinal imaging technology business Optos.

Stockmarket filings released yesterday show the Wellcome Trust purchased 845,000 shares this week.

Using the closing price of 120p on Monday, when the purchase took place, that would mean more than £1 million was spent on the additional stake.

The transaction took the Wellcome Trust's holdings in Optos from almost 2.27 million shares to 3.1 million shares or 4.31% of the issued share capital.

The stock in the Dunfermline based company has been as high as 215.2p this year.

However the share price has been hit as investors reacted negatively to software problems impacting the roll-out of the next generation Daytona retinal scanner and weaker European sales.

The first major dip took place back in March following a disappointing trading update and the second large fall came in May when the shares were trading at around 160p.

Then the shares lost around 17% of their value when the business confirmed in interim results it did not think it would hit profit targets.

Chief executive Roy Davis has insisted Optos is well positioned for future growth and the Daytona device is steadily gaining more traction in optometry markets around the world.

The Wellcome Trust was established in 1936 to fund research on improvements in human and animal health.

The London based charity remains one of the largest non-governmental backers of scientific research around the world.

Share in Optos closed on Friday down 0.5p, or 0.41%, at 121.75p.