Although it's true that aging is the numberone risk factor for cataracts, we don't all age at the same rate. If you've taken good care of yourself, your chronological age, in years, might be somewhat higher than your biological age-measured by the condition of your muscles, brain, lungs, and sensory organs. So what we call aging is, in part, the cumulative effect of damage to the body caused by sun exposure, disease, environment, and a number of other factors.

A lifetime of good health habits probably won't prevent cataracts altogether. If you've been kind to your body, however, it's quite possible that cataracts will develop later and will be less extensive- confined to the nucleus, perhaps, rather than developing in the cortex or the subcapsular area, or both. On the other hand, people with high blood pressure or obesity tend to develop posterior subcapsular cataracts, and taking a thyroid hormone may contribute to cortical-cataract development.