Fellow of the American Board of Ophthalmology (ABO), Board Examiner and Board Exam Writer with a particular interest in state of the art cataract surgery, laser eye surgeries for myopia, cataract, and glaucoma, and state of the art treatments for dry eye disease. Dr. Cremers trained and taught at Harvard Medical School for close to a decade. She conducted research with Dr. Judah Folkman on the angiogenesis bases of ocular rosacea in search for a cure for the many causes of dry eye disease.
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Tuesday, May 21, 2013
How to properly check Intra Ocular eye Pressure (IOP)
Corneal astigmatism can affect Intraocular Pressure IOP measurements.
If there is more than 3.00 D of astigmatism the following is true:
1. results in an under estimation of IOP in with-the-rule astigmatism and an over estimation with against-the-rule astigmatism, with an error range of about -2.5 to +2.5 mmHg.
Two options exist to counteract this source of error:
1. Align tonometer head at 43 degree to axis of astigmatism ( in negative cylinder).
In other word: Set the axial position of the greater radius (that is the axis of a minus cylinder) on the prism graduation at the red mark on the prism holder of the tonometer head.
2. Average IOP readings at 0 and 90 degrees.
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