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Stephen S. Khachikian - One of the best experts on this subject based on the ideXlab platform.

  • tomographic normal values for Corneal elevation and Pachymetry in a hyperopic population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P<0.001). The mean anterior elevation at the thinnest point was-0.1 ± 2.2 µm in the hyperopic group vs. 1.7 ± 2.0 µm in the myopic group (P<0.001). The mean posterior elevation at the apex was5.7 ± 3.6 µm in the hyperopic group vs. 0.8 ± 3.0 µm in the myopic group (P<0.001). The mean posterior elevation at the thinnest point was10.6 ± 5.7 µm for the hyperopic group vs. 3.6 ± 4.1 µm for the myopic group (P<0.001). When adjusted for age, the posterior elevation changes remained statistically significant.   Conclusions: Hyperopic individuals exhibited greater variation in posterior tomographic elevation values than a comparable myopic group. Currently used data bases need to be adjusted for screening hyperopic individuals to reduce the number of false positives associated with using a myopic biased data set.

  • Tomographic Normal Values for Corneal Elevation and Pachymetry in a Hyperopic Population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P

Joan T. Kim - One of the best experts on this subject based on the ideXlab platform.

  • tomographic normal values for Corneal elevation and Pachymetry in a hyperopic population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P<0.001). The mean anterior elevation at the thinnest point was-0.1 ± 2.2 µm in the hyperopic group vs. 1.7 ± 2.0 µm in the myopic group (P<0.001). The mean posterior elevation at the apex was5.7 ± 3.6 µm in the hyperopic group vs. 0.8 ± 3.0 µm in the myopic group (P<0.001). The mean posterior elevation at the thinnest point was10.6 ± 5.7 µm for the hyperopic group vs. 3.6 ± 4.1 µm for the myopic group (P<0.001). When adjusted for age, the posterior elevation changes remained statistically significant.   Conclusions: Hyperopic individuals exhibited greater variation in posterior tomographic elevation values than a comparable myopic group. Currently used data bases need to be adjusted for screening hyperopic individuals to reduce the number of false positives associated with using a myopic biased data set.

  • Tomographic Normal Values for Corneal Elevation and Pachymetry in a Hyperopic Population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P

Jorge L Alio - One of the best experts on this subject based on the ideXlab platform.

  • automated superficial lamellar keratectomy augmented by excimer laser masked ptk in the management of severe superficial Corneal opacities
    British Journal of Ophthalmology, 2004
    Co-Authors: Jorge L Alio, Jaime Javaloy, J Merayo, A Galal
    Abstract:

    Aim: To assess superficial lamellar keratectomy augmented by excimer laser smoothening with sodium hyaluronate 0.25%, for the management of superficial Corneal opacities. Methods: Consecutive procedure performed in 14 eyes (13 patients) with an automated microkeratome and excimer laser phototherapeutic keratectomy (PTK) smoothening using sodium hyaluronate 0.25%. Main outcome measures: UCVA, BCVA, Pachymetry, degree of haze, ray tracing analysis, and complications. Mean follow up was 12 (SD 1.6) months. Results: Mean preoperative haze from previous Corneal refractive surgeries was 3.5 (SD 0.5) (11/14 cases). In one case, opacity was caused by ocular trauma and in two by infectious keratitis. The mean preoperative UCVA was 0.7 logMAR (0.2 (SD 0.13) decimal value). BCVA was 0.4 logMAR (0.4 (SD 0.17) decimal value). Mean preoperative Corneal Pachymetry was 508 (SD 62.5) µm and mean opacity depth measured by Corneal confocal microscopy was 115.2 (SD 49.4) µm. At 6 months, 71.4% of the eyes with previous Corneal refractive surgery showed grade I haze or less. Mean postoperative Corneal Pachymetry at 6 months was 352.36 (SD 49.05) µm. Conclusions: Automated superficial lamellar keratectomy combined with excimer laser PTK smoothening assisted by sodium hyaluronate 0.25% induces a significant improvement of Corneal transparency and visual acuity in cases of Corneal opacity caused by previous refractive surgery, ocular trauma, and keratitis.

  • Comparison of four Corneal Pachymetry technique;s in Corneal refractive surgery.
    Journal of Refractive Surgery, 2004
    Co-Authors: Jaime Javaloy, Alberto Artola, María T Vidal, Jose R. Villada, Jorge L Alio
    Abstract:

    PURPOSE To assess the effectiveness of optical and ultrasonic Pachymetry when examining corneas of patients before and after laser in situ keratomileusis (LASIK). METHODS We conducted a prospective study of 25 patients (50 eyes) who had LASIK for myopia or myopic astigmatism (mean spherical equivalent refraction -4.80 +/- 3.60 D; range -1.75 to -12.00 D). Corneal thickness was measured using 1) conventional ultrasonic Pachymetry (20 MHz probe) in the central cornea, 2) ASL confocal microscopy (CMTF analysis), 3) Orbscan II Analyzer, and 4) ultrasound biomicroscopy (UBM) (50 MHz probe) preoperatively and 3 months postoperatively. RESULTS Preoperative Pachymetry values measured with the Orbscan II Analyzer (551.3 +/- 27.3 microm) were almost identical to those measured with the 20 MHz ultrasonic probe (553.7 +/- 25.7 microm; t-test P = .652). The mean preoperative Pachymetry for UBM was 566.7 +/- 38.8 microm and for CMTF was 553.2 +/- 15.5 microm. The optic and ultrasonic system measurements differed in operated eyes; 20 MHz ultrasonic Pachymetry yielded an average 478.7 +/- 23.5 microm and the UBM, 482.4 +/- 40.3 microm. These measurements differed from the Orbscan II (Tukey test; P = .023) measurement of 461.1 +/- 37.5 microm but not from the confocal microscopy measurement of 475.2 +/- 41.8 microm. UBM registered greater values that were more variable than those obtained with ultrasonic Pachymetry. CONCLUSIONS In non-operated eyes, Corneal thickness was similar using conventional ultrasound, Orbscan II, or confocal techniques, with ultrasound biomicroscopy giving thicker readings.

  • Comparison of Corneal Pachymetry using ultrasound and Orbscan II.
    Journal of Cataract & Refractive Surgery, 2002
    Co-Authors: Mohamed A Fakhry, Alberto Artola, José I. Belda, Ma.josé Ayala, Jorge L Alio
    Abstract:

    Purpose: To compare Orbscan II Pachymetry with ultrasonic Pachymetry in eyes having Corneal refractive surgery. Settings: Instituto Oftalmologico de Alicante, Alicante, Spain. Methods: In this comparative prospective study, 72 eyes (36 patients) were divided into 4 groups: Group 1, 16 eyes with haze after photorefractive keratectomy (PRK); Group 2, 12 eyes with no haze after PRK; Group 3, 24 eyes that had uneventful laser in situ keratomileusis; Group 4, 20 normal eyes. The Corneal thickness was measured in all eyes by the Orbscan II (version 3.27.10, Orbtek Inc.) and then by ultrasonic Pachymetry (DHC 500, Technology Inc.). Results: The results between the 2 systems of Pachymetry were significant in Group 1 (P < .0001) and not significant in Groups 2, 3, and 4 (P = .056, P = .051, and P = .68, respectively). A statistically significant correlation existed between the grade of haze and the decrease in Orbscan readings (C = −0.821, P < .0001). Conclusion: The Orbscan II Pachymetry measurements correlated with the ultrasound measurements in eyes with clear corneas. Haze after PRK decreased the Orbscan Pachymetry.

Günter K. Krieglstein - One of the best experts on this subject based on the ideXlab platform.

  • Central and paracentral Corneal Pachymetry in patients with normal tension glaucoma and ocular hypertension
    Graefe's Archive for Clinical and Experimental Ophthalmology, 2006
    Co-Authors: Jens F. Jordan, Silke Joergens, Sven Dinslage, Thomas S. Dietlein, Günter K. Krieglstein
    Abstract:

    Purpose The difference in central Corneal thickness among subgroups of glaucoma patients, as well as its influence on Goldmann applanation tonometry, has been well documented in several clinical trials. In the present study, possible similarities and differences between central Corneal thickness and Corneal thickness of paracentral quadrants in patients with normal tension glaucoma (NTG) and ocular hypertension (OHT) were investigated. Methods Central and paracentral Corneal thickness was measured by optical slit scan Pachymetry (Orbscan II). Fourteen patients (28 eyes) with NTG and 11 patients (22 eyes) with OHT were included in this study. t -Test was performed for statistical analysis. To evaluate overall Corneal topography, the mean and SD values of the differences between the central Corneal thickness and each peripheral quadrant were analysed. Results The following data was obtained (μm): (central, upper, temporal, nasal, inferior paracentral quadrant): OHT group 617–695–663–687–660. NTG group 568–629–593–612–616. Corneal thickness of all four paracentral quadrants differed significantly between the OHT and NTG groups. There was a more heterogeneous intraindividual pattern of overall Corneal topography in the OHT group, and a more heterogeneous pattern of Corneal topography among the individuals of the NTG group (interindividual heterogeneity). Conclusions A comparison of central Corneal thickness and paracentral Corneal thickness revealed clinically relevant differences between the OHT and NTG groups. The presented data underlines the importance of correlating the site of applanation with the corresponding Corneal thickness, especially in OHT patients. It further substantiates the necessity to obtain individual pachymetric data for each NTG patient.

  • Central and paracentral Corneal Pachymetry in patients with normal tension glaucoma and ocular hypertension
    Graefe's Archive for Clinical and Experimental Ophthalmology, 2005
    Co-Authors: Jens Jordan, Silke Joergens, Sven Dinslage, Thomas S. Dietlein, Günter K. Krieglstein
    Abstract:

    Purpose The difference in central Corneal thickness among subgroups of glaucoma patients, as well as its influence on Goldmann applanation tonometry, has been well documented in several clinical trials. In the present study, possible similarities and differences between central Corneal thickness and Corneal thickness of paracentral quadrants in patients with normal tension glaucoma (NTG) and ocular hypertension (OHT) were investigated.

Michael Cortese - One of the best experts on this subject based on the ideXlab platform.

  • tomographic normal values for Corneal elevation and Pachymetry in a hyperopic population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P<0.001). The mean anterior elevation at the thinnest point was-0.1 ± 2.2 µm in the hyperopic group vs. 1.7 ± 2.0 µm in the myopic group (P<0.001). The mean posterior elevation at the apex was5.7 ± 3.6 µm in the hyperopic group vs. 0.8 ± 3.0 µm in the myopic group (P<0.001). The mean posterior elevation at the thinnest point was10.6 ± 5.7 µm for the hyperopic group vs. 3.6 ± 4.1 µm for the myopic group (P<0.001). When adjusted for age, the posterior elevation changes remained statistically significant.   Conclusions: Hyperopic individuals exhibited greater variation in posterior tomographic elevation values than a comparable myopic group. Currently used data bases need to be adjusted for screening hyperopic individuals to reduce the number of false positives associated with using a myopic biased data set.

  • Tomographic Normal Values for Corneal Elevation and Pachymetry in a Hyperopic Population
    Journal of Clinical & Experimental Ophthalmology, 2011
    Co-Authors: Joan T. Kim, Michael Cortese, Michael W. Belin, Renato Ambrósio, Stephen S. Khachikian
    Abstract:

    Purpose: To establish a normative data base with respect to Corneal Pachymetry and elevation tomography appropriate for refractive surgery screening of hyperopic individuals.   Methods: 100 eyes of 51 consecutive hyperopic patients were examined with the Oculus Pentacam HR to determine Corneal Pachymetry and anterior and posterior elevation values at the apex and thinnest point. All patients were otherwise screened as normal and all principal meridians were hyperopic. Results were compared to a previously studied data base of myopic individuals from the same practice.   Results: The average Corneal thickness at the apex and thinnest point was not significantly different between the hyperopic and myopic groups (P>0.05 at both locations). The mean anterior elevation at the apex was0.4 ± 1.9 µm in the hyperopic group vs. 1.6 ± 1.3 µm in the myopic group (P