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Measuring intraocular pressure using finger tension and 2 different instruments in the immediate postoperative period after penetrating keratoplasty

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First Author: S.Georgaras GREECE

Co Author(s):    S. Georgaras   G. Toliou   E. Patsoura   A. Panagopoulos           

Abstract Details

Purpose:

Raised intraocular pressure, (IOP) after corneal transplant (PKP) is a complication that affects almost one third of the eyes. High IOP may lead to transplant failure and glaucoma, therefore it’s monitoring after PKP is essential. Previous studies demonstrated that on irregular corneas, especially after a transplant, measurements by most tonometers are affected by corneal irregularity and sutures, therefore their accuracy is uncertain. The purpose of this study was to compare measurements taken on day one after PKP using Finger Tension (FT) and Easyton, a new transpalpebral digital tonometer and after one month using Easyton and Goldmann applanation tonometer(GAT).

Setting:

Ophthalmos, Research and Therapeutic Institute, Athens, Greece

Methods:

IOP was measured on 10 eyes that underwent penetrating keratoplasty. Patients had no lid or sclera pathology. On postoperative day one (phase 1), 2 FT estimates were performed by two experienced corneal surgeons at 2 minutes interval. Two consecutive measurements were taken immediately after, using the Easyton by the clinic’s optometrist. One month after keratoplasty (phase 2) when stromal oedema was resolved, two consecutive measurements were taken with the Easyton and two measurements with the Goldmann tonometer an hour later within 2 minutes interval. All measurements were performed by the same examiners as on day one.

Results:

On phase 1 the mean FT estimation exceeded the Easyton reading by 4mmHg. No complications from FT palpation were recorded. Globe tenderness affected the surgeon’s confidence with a tendency to overestimate. On phase 2 there was no significant difference in IOP measured by GAT and Easyton. Mean Goldmann tonometry was 12.9mmHg with a standard deviation of 2.1, and mean Easyton IOP was 13.35 with a standard deviation of 1.9. Deviations (reference tonometer measurement-measurement of Easyton) exceeding permissible deviations in accordance with ANSI Z80-2003 were not revealed.

Conclusions:

In the early postoperative period after penetrating keratoplasty the digital transpalpebral tonometer Easyton may be a suitable alternative of IOP monitoring. It can be used from day one after surgery when GAT or other contact tonometer readings are difficult to obtain, does not require the use of anaesthetics and measurements are not affected by corneal irregularities, oedema or astigmatism. Results depend on the correct position of the patient’s head and the tonometer’s support on the eyelid. In our study, IOP tends to be overestimated with the FT method which still remains a useful technique.

Financial Disclosure:

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