Look out for glaucoma.

We should have our eyes tested annually – especially after age 40, when reading the small print may become increasingly difficult. More serious than age related vision loss, however, is glaucoma – another reason to see your ophthalmologist annually.
Glaucoma is a condition that involves abnormally elevated intra-ocular pressures (pressure within the eyes.) Remember, a check up for vision at an optician may not include the measurement of intra-ocular pressure, so a comprehensive eye examination is required.
If you are at a higher than normal risk of developing glaucoma - adults with severe myopia, diabetes, or a family history of glaucoma – you should have your eye pressures checked yearly. While there is no formal screening recommendation for healthy subjects with normal risk, everybody over 60 years should have eye pressure measurements periodically, perhaps annually.
Because glaucoma causes extensive damage to retina and irreversible loss of vision without waning symptoms and before the individual becomes aware of loss of vision, the benefits of early detection are clear. There is also good evidence that treatment of elevated eye pressure in glaucoma can prevent blindness.