The easy answer is that your prescription as you have written it is outside published limits.
Nevertheless I think it would be worth having an up to date eye test and asking your optician to fill out the CAA eye examination form,
http://www.caa.co.uk/docs/49/Ophthal...m%20MED162.pdf then submitting the lot to the CAA at Gatwick and asking in writing a) whether you have a chance of Class 1 certification as you stand, and b) if not, would refractive surgery(with all the risks involved) give you a chance.
you can look at
Guidance following eye surgery | Medical | Personal Licences and Training
and
http://www.caa.co.uk/docs/1859/FinalspeccalcV6.6.xlsx
but for the sake of an eye test and a letter, I would still write to them.
FWIW It looks like you would be ok for a PPL medical but that is not the question you asked.