Do I really need cataract surgery now?

Behind your pupil there is a clear lens. Over years it goes yellow and cloudy. Light gets scattered, so colours look dull, headlights spread out at night, and reading needs more light than before.

Surgery takes the cloudy lens out and puts a clear plastic one in. It is a good operation. The question is only whether you need it this month.

• You have stopped driving at night, or stopped going out, because of your sight.
• New glasses no longer help.
• The cataract has gone very hard and white, which makes surgery harder later.
• Your doctor cannot see your retina properly to treat another problem.
• The cataract is pushing your eye pressure up.

• You still read, cook, work and walk about comfortably.
• A change of glasses has just improved things.
• The cloudiness was found on a routine check and does not bother you.
• Only one eye is affected and the other sees well.

Waiting does not damage the eye in most ordinary cataracts. You can be checked again in six or twelve months.

You may be offered a costly lens — multifocal, toric, extended range. Sometimes it is worth it. Sometimes a simple lens plus reading glasses gives you the same happiness for a fraction of the price. Ask why that particular lens suits your eye, and what happens if you dislike the result.

• Ask how much of your blurred vision is from the cataract and how much from something else.
• Ask what happens if you wait six months.
• Ask for the total cost in writing, including the lens and follow-up visits.
• Get the reports: the prescription, the biometry printout and any retina scan. Those are the papers a second opinion needs.

Your eye is red and painful, you suddenly lost vision, or you see flashes or a dark curtain. That is not a cataract problem and it will not wait.