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Objective: This study sets out to determine if there is any statistical difference in the results of measuring intraocular pressure (IOP) uncorrected for Central Corneal Thickness with Air Puff Tonometry and corrected with pachymetry for clients undergoing screening for glaucoma at the department of Ophthalmology, University of Port Harcourt Teaching Hospital (UPTH), Nigeria.
Methods: One hundred and thirty-two (132) adults were screened for glaucoma during the 2019 World Glaucoma week in UPTH Port Harcourt, they had their IOPs measured with Air Puff (Non-contact) Tonometer (Pulsair intelliPuff Tonometer, Keeler), after which they underwent pachymetry (Sonomed Escalon PacScan Plus) to determine corneal thickness after which the corrected IOP was determined by using a correction factor for adjusting IOP based on corneal thickness . The results were analyzed using SPSS version 20 to determine statistical differences.
Results: There was a statistically significant difference between intraocular pressure (IOP) measurements when corrected with pachymetry than when it is uncorrected. In our study the mean uncorrected IOP RE and LE was 14.53 mmHg and14.75 mmHg respectively while Corrected IOP RE and LE was 16.37 mmHg and 16.72 mmHg respectively.
Conclusion: Intra ocular pressure measurement adjusted with pachymetry for corneal thickness may be a better option for tonometry and we propose this be considered during intra ocular pressure measurement.
Prum Jr. BE, Herndon Jr. LW, Moroi SE, Mansberger SL, Stein JD, Lim MC, et al. Primary angle closure preferred practice pattern guidelines. Ophthalmology. 2016; 123(1):1–40.
Prum Jr BE, Lim MC, Mansberger SL, Stein JD, Moroi SE, Gedde SJ, et al. Primary open angle glaucoma suspect preferred practice pattern guidelines. Ophthalmology. 2016;123(1):112–151.
The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. The AGIS Investigators. Am J Ophthalmol. 2000;130:429e440.
O’Brien C, Schwartz B, Takamoto T. Intraocular pressure and the rate of visual fifield loss in chronic open-angle glaucoma. Am J Ophthalmol. 1991;111:491e500.
Leske MC, Heijl A, Hyman L, et al. Predictors of long-term progression in the early manifest glaucoma trial. Ophthal mology. 2007;114:1965e1972.
Medeiros FA, Weinreb RN. Evaluation of the inflfluence of corneal biomechanical properties on intraocular pressure measurements using the ocular response analyzer. J Glaucoma. 2006;15:364e370.
Whitacre MM, Stein R. Sources of error with use of Goldmann-type tonometers. Surv Ophthalmol. 1993;38:1e30.
Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: A review. JAMA. 2014;311: 1901e1911.
Mrunal Patil, Dhiraj Balwir, Hardik jain. Correlation between central corneal thickness and intraocular pressure among normal IOP, ocular hypertensive and primary open angle glaucoma patients. MVP Journal of Medical Sciences 2017; 4(2):144-147.
Ouyang PB, Li CY, Zhu XH, Duan XC. Assessment of intraocular pressure measured by Reichert ocular responsean alyzer, Goldmann applanation tonometry, and dynamic contour tonometry in healthy individuals. Int J Ophthalmol. 2012;5: 102e107.
Jorge JM, Gonzalez-Meijome JM, Queiros A, et al. Correlations between corneal biomechanical properties measured with the ocular response analyzer and I Care rebound tonometry. J Glaucoma. 2008; 17:442e448.
Chui WS, Lam A, Chen D, Chiu R. The influence of corneal properties on rebound tonometry. Ophthalmology. 2008;115: 80e84.
Liu J, Roberts CJ. Influence of corneal biomechanical properties on intraocular pressure measurement: Quantitative analysis. J Cataract Refract Surg. 2005;31: 146e155.
Committee of the Japan Glaucoma Society Guidelines for Glaucoma. The Japan Glaucoma Society guidelines for glaucoma. (3rd edition). Nippon Ganka Gakkai Zasshi. 2012;116(1):3-46.
Goldmann H, Schmidt T. Applanation tonometry. Ophthalmologica 1957;134(4): 221-242.
Ehlers N, Hansen FK, Aasved H. Biometric correlations of corneal thickness. Acta Ophthalmol (Copenh). 1975;53(4):652-659.
Kiyoshi Yaoeda, Atsushi Fukushima, Motohiro Shirakashi, Takeo Fukuchi. Comparison of intraocular pressure adjusted by central corneal thickness or corneal biomechanical properties as measured in glaucomatous eyes using noncontact tonometers and the Goldman applanation tonometer. Clin Ophthalmol. 2016;10:829-834.
Tonnu PA, Ho T, Newson T, El Sheikh A, Sharma K, et al. The influence of central corneal thickness and age on intraocular pressure measured by pneumotonometry, non-contact tonometry, the Tono-Pen XL, and the Goldmann applanation tonometry. BJ Ophthalmol. 2004;89(7).
Gordon MO, Beiser JA, Brandt JD, et al. The ocular hypertension treatment study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120:714-720.
Singh RP, Goldberg I, Graham SL, et al. Central corneal thickness, tonometry, and ocular dimensions in glaucoma and ocular hypertension. J Glaucoma. 2001;10:206-210.
Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: A review and meta-analysis approach. Surv Ophthalmol. 2000; 44:367-408.
Sood A, Nazir A, Runyal F, Mohiudin S, Sadiq T. Clinical estimation of intraocular pressure with a non-contact tonometer and Goldman applanation tonometer as a tool for mass screening and its correlation with central corneal thickness: A comparative hospital based study. Global Journal of Medicine and Public Health. 2015;4(4).
Babalola OE, Kehinde AV, Iloegbunam AC, Akinbinu T, Moghalu C, Onuoha I. Ophthalmic Physiol Opt. 2009;29(2):182-188.
Oladigbolu K, Abdullahi H, Abdulsalam H, Gana O, Kadala N, Pam V. Central corneal thickness measurement of non-glaucomatous adults in Ahmadu Bello University Sick Bay, Samaru, Zaria. Sub-Saharan Afr J Med 2018;5:69-73.
Onochie C, Okoye O, Ogunro A, Aribaba T, Hassan K, Onakoya A. Comparisons of the tono-pen and goldmann applanation tonometer in the measurement of intraocular pressure of primary open angle glaucoma patients in a Hospital population in South-West Nigeria. Med Princ Pract. 2016;25:566-571.
Iyamu E, Ituah I. The relationship between central corneal thickness and intraocular pressure: A comparative study of normal and glaucoma suspects. Afr J Med Sci. 2008;37(4):345-353.
Egwuonwu NNN, Central corneal thickness in Nigerians: A population-based study in Lagos State. Glaucoma Clinical Research. 2012;462.
Mercieca K, Odogu V, Fiebai B, Arowolo O, Chukwuka F. comparing central corneal thickness in a sub-Saharan cohort to African Americans and Afro-Caribbeans. Cornea. 2007;26 (5):557-560.
Nkanga DG, Ibanga AA, Nkanga ED, Etim BA, Nwachukwu KU, Ogba PO. Role of central corneal thickness measurement in management of open angle glaucoma and glaucoma suspects in Calabar, Nigeria. IAIM. 2017;4(7):131-138.
Muhsin Eraslan, Eren Cerman, Sena Summen. Comparison of intraocular pressure measurements in healthy paediatric patients using three types of tonometers. Turk J Ophthalmol. 2017; 47(1):1-4.
Mahmoud A. Fayed, Teresa C. Chen. Paediatric intraocular pressure measurements: Tonometers, central corneal thickness and anesthesia. Survey of Ophthalmology. 2019;64(4):810-825.