Question: I've never asked, or been told, my cup to disc ratio. Is this something I should be asking about on a regular basis?
Answer: Some patients like to know every detail of their current status, including cup-disc ratio or optic nerve appearance, while others prefer only the big picture. As long as your doctor is routinely monitoring your optic nerve, you're OK. However, it's reasonable to ask: How is my optic nerve? Does it show damage? A lot, a little? Is it getting worse?
Question: How much damage does a .5 cup to disk ratio indicate? Is this measurement subjective?
Answer: Cup-disc ratio is a traditional measure that has its own strengths and weaknesses. It is somewhat subjective, but a given individual's doctor is usually pretty consistent, so it can be used to compare over time. There is a large overlap of normal and abnormal cup-disc ratios, and the cup-disc ratio describes only one aspect of the nerve, and may not convey subtle but important findings. For a large disc, a ratio of 0.5 may be perfectly normal; for a small disc, this ratio could be consistent with glaucoma. In knowing whether a ratio is abnormal, it's most helpful to know if the ratio has changed over time.
