Ambio 22: 417-426. soil organic matter and acid soils predominate. case in many of the soils inthe warm-humid tropics. of agricultural and charcoal production. cut and burned to allow planting of crops. cycles before the land has to revert back to fallow. and added to soil.
â¢ People ages 20 to 40 should have an eye exam at least every five years unless there are vision changes, pain, flashes of light, new floaters, injury or tearing. Immediate care is needed to address any of those symptoms.
Some people shouldn't wait until they are 40 to have a comprehensive eye exam. If you have an eye disease or if you have a risk factor for developing one, such as diabetes, high blood pressure or a family history of eye disease, you should see an ophthalmologist even if you are younger than 40. Upon examining your eyes, your Eye M.D. can tell you how often you should undergo an eye exam.