Patients who develop a common sight problem face having surgery on one eye but not the other as health bosses tighten up the rules for certain types of surgery.

The move by South Norfolk Clinical Commissioning Group (CCG) has been described as 'unusual' by eye experts while the Royal National Institute of Blind People (RNIB) said it was 'extremely concerned'.

But the CCG, which faces a £6.6m deficit at the end of this financial year, says it is acting responsibly and ensuring its finances are spent carefully.

It has written to GPs informing that 31 surgeries for patients, including second eye cataract, will now be automatically rejected unless clinicians can demonstrate an exception should be made.

Cataracts can occur once in each eye, and fixing it is the most commonly performed NHS operation.

But while the CCG provides surgery for a patient's first cataract, clinicians have been told to explore all other alternatives before applying to the CCG for a second cataract surgery.

Approximately 40pc of patients who get cataracts in one eye get another cataract in the other eye.

Holly Heath, eye health policy and campaigns officer at the RNIB, said removing a cataract from one eye and leaving the other with a cataract meant a patient's vision would be out of balance, putting them at risk of falls.

'Patients tell us of their frustration at having lengthy waits for cataract surgery and their distress at having to live with reduced vision,' she said.

'RNIB strongly believes that everyone who has a sight-threatening condition deserves early access to treatments; no one should have to live with sight loss unnecessarily.'

And Professor Carrie Macewan, president of the Royal College of Ophthalmologists, said: 'It's an unusual thing to do.

'Having cataract in one eye damages a person's depth perception and field vision.'

'We have very clear guidelines based on evidence, supported by the National Institute for Clinical Excellence, that patients benefit from having second eye surgery.'

A spokesman for the CCG said: 'There is going to be increased rigour around whether exceptions to policy should be made in individual cases.

'This is a proper stance for a responsible NHS commissioning body to take and will also ensure NHS resources are spent carefully at a time of very significant financial pressure.'

The CCG has already cut other services, such as IVF treatment and gluten-free prescriptions, as it bids to save money.

Have you got a health story? Email nicholas.carding@archant.co.uk