Clinical trial NCT00834782: Comparison of DCT, ORA and GAT in Eyes After Penetrating Keratoplasty
Official title: Comparison of Pascal Dynamic Contour Tonometer, Reichart Ocular Response Analyzer and Goldmann Applanation Tonometer in Eyes After Penetrating Keratoplasty
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Corneal Transplantation
Keywords: PK
IOP
Lead sponsor: Sheba Medical Center
Sponsor class: OTHER_GOV
First posted: 2009-02-03
Enrollment: 35
Sex: ALL
Minimum age (years): 18
Maximum age (years): 90
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Patients post keratoplasty surgery

Brief summary: To compare intraocular pressure (IOP) measured by the Reichert Ocular Response Analyzer (ORA), Pascal dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT) in eyes after Penetrating Keratoplasty (KPL)

Detailed description: A few tonometers are used today in clinical practice for measuring intra ocular pressure (IOP). Each tonometer is based on different technology.

Post penetrating keratoplasty (PK) eyes are at risk for developing secondary glaucoma (9-14%). Elevation of the IOP may cause rejection of the graft or alternately a loss in the endothelial cell layer count causing decompensation of the cornea. Therefore, measuring accurately the IOP in this population is of great importance.

Measuring IOP in post PK is not an easy challenge, mainly because of parameters like the central corneal thickness (CCT), the curvature of the cornea, the axial length and biomechanical properties which diverse from normal eyes.

The Goldmann applanation tonometer (GAT) is the gold standard tonometer for measuring IOP and is the most popular tonometer clinically used. IOP measurements via the GAT are based on the assumption that the CCT is constant. post PK eyes CCT might diverse from normal eyes causing GAT IOP measurements to be inaccurate. The Pascal dynamic contour tonometer (DCT) measures IOP independently of corneal parameters. The Ocular response analyzer (ORA) is based on a non contact technique of measurement. The tonometer is thought to be independent of factors such as CCT.

The aim of the study is to compare intraocular pressure (IOP) measured by the Reichert Ocular Response Analyzer (ORA), Pascal dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT) in eyes after Penetrating Keratoplasty (KPL). In addition its aim is to discover the dependence of different parameters, like - CCT, curvature of the cornea, axial length and biomechanical properties on IOP measurement to elucidate the appropriate tonometer for this population.

Eligibility criteria: Inclusion Criteria:

* Eyes after KPL surgery at the Goldschleger Eye Institute in the last 10 years.

Exclusion Criteria:

* Uncooperative subjects for whom good quality results are unattainable.

Primary outcomes:
measure: Intra ocular pressure
timeFrame: 1 year
Secondary outcomes:
measure: Corneal compensated intra ocular pressure, Corneal hysteresis, Corneal resistance factor
timeFrame: 1 year
Other outcomes:
Locations:
city: Ramat Gan
country: Israel
facility: Goldschleger eye institute, Sheba medical center
city: Ramat Gan
country: Israel
facility: The Goldschleger eye institute, Sheba Medical Center, Tel Aviv University
Study officials:
affiliation: Sheba medical center, head of Sam rotberg glaucoma center
name: Shlomo Melamed, Prof
role: STUDY_CHAIR
References:
citation: Congdon NG, Broman AT, Bandeen-Roche K, Grover D, Quigley HA. Central corneal thickness and corneal hysteresis associated with glaucoma damage. Am J Ophthalmol. 2006 May;141(5):868-75. doi: 10.1016/j.ajo.2005.12.007. Epub 2006 Mar 9.
citation: Jain AK, Saini JS, Gupta R. Tonometry in normal and scarred corneas, and in postkeratoplasty eyes: a comparative study of the Goldmann, the ProTon and the Schiotz tonometers. Indian J Ophthalmol. 2000 Mar;48(1):25-32.
citation: Kerautret J, Colin J, Touboul D, Roberts C. Biomechanical characteristics of the ectatic cornea. J Cataract Refract Surg. 2008 Mar;34(3):510-3. doi: 10.1016/j.jcrs.2007.11.018.
citation: Luce DA. Determining in vivo biomechanical properties of the cornea with an ocular response analyzer. J Cataract Refract Surg. 2005 Jan;31(1):156-62. doi: 10.1016/j.jcrs.2004.10.044.
citation: Medeiros FA, Weinreb RN. Evaluation of the influence of corneal biomechanical properties on intraocular pressure measurements using the ocular response analyzer. J Glaucoma. 2006 Oct;15(5):364-70. doi: 10.1097/01.ijg.0000212268.42606.97.
citation: Mollan SP, Wolffsohn JS, Nessim M, Laiquzzaman M, Sivakumar S, Hartley S, Shah S. Accuracy of Goldmann, ocular response analyser, Pascal and TonoPen XL tonometry in keratoconic and normal eyes. Br J Ophthalmol. 2008 Dec;92(12):1661-5. doi: 10.1136/bjo.2007.136473. Epub 2008 Aug 29.
citation: Pandav SS, Sharma A, Gupta A, Sharma SK, Gupta A, Patnaik B. Reliability of proton and goldmann applanation tonometers in normal and postkeratoplasty eyes. Ophthalmology. 2002 May;109(5):979-84. doi: 10.1016/s0161-6420(02)00974-0.
citation: Rao VJ, Gnanaraj L, Mitchell KW, Figueiredo FC. Clinical comparison of ocular blood flow tonometer, Tonopen, and Goldmann applanation tonometer for measuring intraocular pressure in postkeratoplasty eyes. Cornea. 2001 Nov;20(8):834-8. doi: 10.1097/00003226-200111000-00011.
citation: Touboul D, Roberts C, Kerautret J, Garra C, Maurice-Tison S, Saubusse E, Colin J. Correlations between corneal hysteresis, intraocular pressure, and corneal central pachymetry. J Cataract Refract Surg. 2008 Apr;34(4):616-22. doi: 10.1016/j.jcrs.2007.11.051.