Same-day rebound tonometry may streamline preoperative evaluations
Rebound tonometry did not affect corneal surface properties or preoperative corneal measurements.
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Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
Accurate preoperative corneal measurements before cataract surgery or refractive surgery are critical for excellent results. Unfortunately, due to the need for IOP measurement and its effect on the cornea, it is not always possible to do corneal measurements on the day of the initial exam. This may lead to extra visits, extra patient co-pays and complications of intraoffice patient flow. This month, Jodi I. Luchs, MD, discusses the use of the Icare tonometer for IOP measurements, how it affects corneal measurements and how it may simplify patient flow. We hope you enjoy this discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
Goldmann applanation tonometry has been considered the gold standard for obtaining IOP measurements. However, in order to perform the measurement, an anesthetic must be used, and the device makes actual contact with the cornea. This can be uncomfortable for a patient and usually results in reflex blinking.
But the use of a device such as the Icare tonometer, which does not require an anesthetic and makes minimal contact with the cornea, is an attractive option because we can obtain an accurate pressure measurement without potentially altering the corneal surface.
Applanation tonometry performed before biometric procedures, such as keratometry, can affect the validity of the measurements.
My colleagues and I evaluated visual acuity testing, corneal topography, grading of corneal staining and keratometry on both eyes of 60 randomly selected, previously scheduled patients. The outcomes were compared with an Icare ic100 (Icare) hand-held portable rebound tonometer on one randomly selected eye only. Corneal topography, corneal staining and keratometry were then immediately repeated on both eyes.
The primary outcome of the study was to evaluate if rebound tonometry induces corneal changes that can alter preoperative cataract and refractive surgery testing.
The Icare device does not require anesthetic or drops and takes approximately 15 seconds per eye to use. In our cohort, none of the 60 study eyes developed increased staining scores after rebound tonometry testing, with mean scores of 0.23 pretest compared with 0.22 posttest. No statistically significant differences were found from the first measurement to the second measurement between the study eyes in both mean keratometry and total corneal cylinder, each obtained by Pentacam (Oculus) and IOLMaster (Zeiss).
The absolute value of change in mean keratometry was 0.0238 D in the study group compared with 0.0029 D in the control group when measured by the IOLMaster. When measured by the Pentacam, the absolutely value of change in the study group was 0.025 D in the study group compared with 0.0467 D in the control group.
The average total corneal cylinder was 0.84 D measured by the Pentacam before rebound tonometry and 0.83 D after IOP measurement in the study group. When measured with the IOLMaster, the average total corneal cylinder was 0.9 D both before and after IOP measurements were performed in the study group. There was no statistically significant difference in the change in any of these measurements in the study eye as compared with the control eye.
The ability to perform preoperative refractive or cataract surgery measurements and IOP measurements on the same day is a significant advantage for ophthalmologists and would streamline office visits.
This may also be a good choice to check pressure in patients who have preexisting ocular surface disease. A technician can safely check the pressure so you have the information when the patient sits down, and yet you can still evaluate the ocular surface and not have it altered by any previous drops or mechanical alterations.
Being able to counsel patients on their cataract or refractive surgery options on the same day is preferred over bringing a patient back for another appointment. It negates an additional trip to the office, it saves the clinic time, and it often results in one less co-pay for the patient.
The Icare did not produce any alterations in surface staining or other important measurements evaluated in the trial.
- For more information:
- Jodi I. Luchs, MD, can be reached at Florida Vision Institute, 1515 N. Flagler Drive, West Palm Beach, FL, 33401; email: jluchs@aol.com.
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