| Cornea |
Question: Can anything other than laser extraction be used to remove a calcium deposition in the cornea?
Answer:
EDTA is a chemical solution that dissolves calcium and pulls it from the cornea where it is deposited. Using EDTA (ethyl amino tetra acetic acid) to chelate the calcium might be safer than using a laser. However, this is in the domain of cornea specialists, so I defer to them.
Dr. Rick Wilson
October 18, 2006
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Question: How is IOP corrected for corneal thickness?
Answer:
As a very general rule of thumb, we add or subtract 1 mm of IOP for every 20 microns that the cornea is thicker or thinner than 540 microns. We are just learning about all the other physiologic characteristics of the cornea that affect IOP, so this rule may not be all that accurate.
Dr. Rick Wilson
April 4, 2006
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Question: What is the relation between corneal thickness and IOP and glaucoma?
Answer:
There are two aspects of corneal thickness. Thin corneas give IOP readings lower than what the patient has; the opposite occurs with thick corneas. And it seems that thin corneas may be a marker for a slightly increased susceptibility for glaucoma damage.
Dr. Rick Wilson
March 15, 2006
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Question: What are dellen?
Answer:
If you have had a trabeculectomy that caused an elevation of the conjunctiva high enough to interfere with your lid washing tears over your cornea, then dry areas can form and thin the cornea. These are called delle (just one) or dellen (more than one). If you have them, then you should be seeing an ophthalmologist.
Dr. Rick Wilson
August 2005
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Question: What are the side effects of 5-FU on the cornea? Would four injections in four months cause a problem?
Answer:
The anti-metabolite 5-FU slows down the healing of the cornea. Since the surface of the cornea is renewing itself all the time, slowing down the process can result in raw spots on the corneal surface. Four 5-FU shots over time are unlikely to have much effect on the cornea.
Dr. Rick Wilson
August 2005
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Question: Can Flomax [a prostate medication] cause flat iris, even a year after I've stopped taking it? Thus complicating glaucoma and cataract surgery?
Answer:
Very true indeed. It is not clear yet, but these effects seem to be very long lasting.
Click here for information on prostate drugs and eye surgery.
Dr. Rick Wilson
February 8, 2006
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Question: Can you have LASIK if you have glaucoma?
Answer:
Mild to moderate glaucoma is usually not a problem for LASIK. However, most of us would avoid LASIK in severe glaucoma patients with advanced damage. During LASIK, a suction cup is placed on the eye to stabilize and fixate the eye when the corneal flap is cut, raising the intraocular pressure (IOP) to very high levels for a short period of time. The resulting risk to the remaining optic nerve of patients with advanced glaucoma is excessive.
Dr. Elliot Werner
September 7, 2005
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Question: Does LASIK cause inaccurate intraocular pressure (IOP) measurements?
Answer:
After LASIK, the IOP reads a little lower than it really is, but we can adjust for that.
September 7, 2005
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Question: How is intraocular pressure (IOP) corrected for different corneal thickness? What central corneal thickness (CCT) is normal?
Answer:
Normal CCT is between 520 and 580 microns. There are correction formulas, but most clinicians just recognize that a very thin cornea means the IOP is higher than measured and a very thick cornea means the opposite.
Dr. Elliot Werner
September 7, 2005
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Question: Does a central corneal thickness (CCT) reading on an eye with iridocorneal endothelial syndrome (ICE) have any value?
Answer:
It can help monitor the progress if the cornea gets thicker with time. The findings about CCT and glaucoma are for primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) patients with normal corneas; they are not useful in patients with corneal diseases such as ICE.
Dr. Elliot Werner
September 7, 2005
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Question: How are endothelial cells counted?
Answer:
Endothelial cell count is usually determined by a machine that takes a photograph of the cornea's under/inner side, and then counts the individual cells for a given area. It's not painful, and it's quick.
Dr. Jonathan Myers
December 7, 2005 |
Question: What does an ECC (endothelial cell count) tell us?
Answer:
The cornea, the clear covering of the eye, is kept clear and healthy by a lining of cells on its inner side, the endothelial cells. With age, multiple surgeries, and other eye conditions, there are fewer endothelial cells. As the number of cells drops, the ability of the cornea to maintain clarity drops. A low endothelial cell count may suggest that surgery, such as cataract or glaucoma surgery, carries a higher risk of reduced corneal clarity and the need for a corneal transplant.
Dr. Jonathan Myers
December 7, 2005 |
