Main Article Content
Abstract
BACKGROUND
Precise central corneal thickness (CCT) measurement is of utmost importance in various corneal diseases and refractive procedures. Various methods are available to measure CCT. But studies comparing CCT measurements with different devices have shown variable results. This study compares the CCT measurements by different devices and Ultrasound Pachymetry (USP).
METHODS
This prospective study that was conducted from October 2017 to June 2019 included 100 subjects aged more than 18 years and CCT was measured by non-contact specular microscopy (NCSM), spectral domain optical coherence tomography (SD-OCT), optical biometry (OB) and USP in normal eyes. For every patient and with each device, three readings were taken and an average was recorded. The data recorded per protocol was analyzed using Intraclass correlation coefficient and Bland-Altman analysis.
RESULTS
The mean value of CCT with NCSM, SD-OCT, OB, USP was 528.98±32.18µm, 532.64±30.49µm, 517.47±31.89µm and 533.39±33.44µm, respectively. The intraclass correlation was found to be maximum between NCSM and USP (0.953, p<0.001). The mean paired difference of CCT values with SD-OCT and USP was statistically insignificant (-0.75±14.73, p=1.00) whereas the difference obtained with all other devices was statistically significant.
CONCLUSIONS
A statistically significant positive correlation (p<0.001) was observed on comparing all the four devices with each other for measurement of CCT. The OCT had the best agreement and also positively correlated with USP. Hence, we conclude that OCT can be an effective alternative to USP for measuring CCT.
Keywords
Article Details
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References
- Cheng H, Bates AK, Wood L, et al. Positive correlation of corneal thickness and endothelial cell loss. Serial measurements after cataract surgery. Arch Ophthalmol 1988;106(7):920-2.
- Auffarth GU, Wang L, Volcker HE. Keratoconus evaluation using the orbscan topography system. J Cataract Refract Surg 2000;26(2):222-8.
- Rabinowitz YS. Ectasia after laser in situ keratomileusis. Curr Opin Ophthalmol 2006;17(5):421-6.
- Rad AS, Jabbarvand M, Saifi N. Progressive keratectasia after laser in situ keratomileusis. J Refract Surg 2004;20(5):S718-22.
- Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: A review and meta-analysis approach. Surv Ophthalmol 2000;44(5):367-408.
- Weinreb RN, Lu A, Beeson C. Maternal Corneal thickness during pregnancy. Am J Ophthalmol 1988;105(3):258-60.
- Bayhan HA, Bayhan SA, Can I. Comparison of central corneal thickness measurements with three new optical devices and a standard ultrasonic pachymeter. Int J Ophthalmol 2014;7(2):302-8.
- Calvo-Sanz JA, Ruiz-Alcocer J, Sanchez-Tena MA. Accuracy of cirrus HD-OCT and topcon SP-3000P for measuring central corneal thickness. J Optom 2018;11(3):192-7.
- Al-Ageel S, Al-Muammar AM. Comparison of central corneal thickness measurements by pentacam, noncontact specular microscope and ultrasound pachymetry in normal and post-LASIK eyes. Saudi J Ophthalmol 2009;23(3-4):181-7.
- Khaja WA, Grover S, Kelmenson AT. Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan. Clin Ophthalmol 2015;9:1065-70.
- Huang J, Lu W, Savini G, et al. Comparison between a new optical biometry device and an anterior segment optical coherence tomographer for measuring central corneal thickness and anterior chamber depth. J Ophthalmol 2016;2016:6347236.
- Cevik SG, Duman R, Cevik MT, et al. Comparison of central corneal thickness estimated by an ultrasonic pachymeter and non-contact specular microscopy. Arq Bras Oftalmol 2016;79(5):312-4.
References
Cheng H, Bates AK, Wood L, et al. Positive correlation of corneal thickness and endothelial cell loss. Serial measurements after cataract surgery. Arch Ophthalmol 1988;106(7):920-2.
Auffarth GU, Wang L, Volcker HE. Keratoconus evaluation using the orbscan topography system. J Cataract Refract Surg 2000;26(2):222-8.
Rabinowitz YS. Ectasia after laser in situ keratomileusis. Curr Opin Ophthalmol 2006;17(5):421-6.
Rad AS, Jabbarvand M, Saifi N. Progressive keratectasia after laser in situ keratomileusis. J Refract Surg 2004;20(5):S718-22.
Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: A review and meta-analysis approach. Surv Ophthalmol 2000;44(5):367-408.
Weinreb RN, Lu A, Beeson C. Maternal Corneal thickness during pregnancy. Am J Ophthalmol 1988;105(3):258-60.
Bayhan HA, Bayhan SA, Can I. Comparison of central corneal thickness measurements with three new optical devices and a standard ultrasonic pachymeter. Int J Ophthalmol 2014;7(2):302-8.
Calvo-Sanz JA, Ruiz-Alcocer J, Sanchez-Tena MA. Accuracy of cirrus HD-OCT and topcon SP-3000P for measuring central corneal thickness. J Optom 2018;11(3):192-7.
Al-Ageel S, Al-Muammar AM. Comparison of central corneal thickness measurements by pentacam, noncontact specular microscope and ultrasound pachymetry in normal and post-LASIK eyes. Saudi J Ophthalmol 2009;23(3-4):181-7.
Khaja WA, Grover S, Kelmenson AT. Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan. Clin Ophthalmol 2015;9:1065-70.
Huang J, Lu W, Savini G, et al. Comparison between a new optical biometry device and an anterior segment optical coherence tomographer for measuring central corneal thickness and anterior chamber depth. J Ophthalmol 2016;2016:6347236.
Cevik SG, Duman R, Cevik MT, et al. Comparison of central corneal thickness estimated by an ultrasonic pachymeter and non-contact specular microscopy. Arq Bras Oftalmol 2016;79(5):312-4.