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Al-Sharify NT, Nser HY, Ghaeb NH, Al-Sharify ZT, See OH, Weng LY, Ahmed SM. Influence of different parameters on the corneal asphericity (Q value) assessed with progress in biomedical optics and imaging - A review. Heliyon 2024; 10:e35924. [PMID: 39224364 PMCID: PMC11367468 DOI: 10.1016/j.heliyon.2024.e35924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/20/2024] [Accepted: 08/06/2024] [Indexed: 09/04/2024] Open
Abstract
The corneal eye diseases such as Keratoconus cause weakening of the cornea, with this disease the cornea can change in shape. This condition affects between 1 in 3,000 to 1 in 10,000 people. The main reason for the development of such conditions is unknown and can have significant impacts. Over the last decade, with advancements in computerized corneal topography assessments, researchers have increasingly expressed interest in corneal topography for research as well as clinical activities. Up till now, several aspheric numerical models have been developed as well as proposed to define the complex shape of the cornea. A commonly used term for characterizing the asphericity in an eye is the Q value, a common indicator of the aspherical degree of the cornea. It is one of the critical parameters in the mathematical description model of the cornea as it represents the cornea's shape and the eye's characteristics. Due to the utmost importance of this Q value of the cornea, a couple of studies have attempted to explore this parameter and its distribution, merely in terms of its influence on the human eye's optical properties. The corneal Q value is an important factor that needs to be determined to treat for any refractive errors as corneal degeneration are disease that can lead to potential problems with the structure of the cornea. This study aims to highlight the need to understand Q value of the cornea as this can essentially assist with personalising corneal refractive surgeries and implantation of intraocular lenses. Therefore, the relevance of corneal Q value must be studied in association with different patients, especially ones who have been diagnosed with cataracts, brain tumours, or even COVID-19. To address this issue, this paper first carries out a literature review on the optics of the cornea, the relevance of corneal Q value in ophthalmic practice and studies corneal degenerations and its causes. Thereafter, a detailed review of several noteworthy relevant research studies examining the Q value of the cornea is performed. To do so, an elaborate database is created, which presents a list of different research works examined in this study and provides key evidence derived from these studies. This includes listing details on the age, gender, ethnicity of the eyes assessed, the control variables, the technology used in the study, and even more. The database also delivers important findings and conclusions noted in each study assessed. Next, this paper analyses and discusses the magnitude of corneal Q value in various scenarios and the influence of different parameters on corneal Q value. To design visual optical products as well as to enhance the understanding of the optical properties of an eye, future studies could consider the database and work presented in this study as useful references. In addition, the work can be used to make informed decisions in clinical practice for designing visual optical products as well as to enhance the understanding of the optical properties of an Eye.
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Affiliation(s)
- Noor T. Al-Sharify
- Department of Electrical & Electronic Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
- Medical Instrumentation Engineering Department, Al-Esraa University College, Baghdad, Iraq
| | - Husam Yahya Nser
- Department of Electrical & Electronic Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
| | - Nebras H. Ghaeb
- Biomedical Engineering Department, Al Khawarezmi, Engineering College, University of Baghdad, Iraq
| | - Zainab T. Al-Sharify
- Department of Pharmacy, Al Hikma University College, Baghdad, Iraq
- School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT, Birmingham, United Kingdom
| | - Ong Hang See
- Department of Electrical & Electronic Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
| | - Leong Yeng Weng
- Department of Electrical & Electronic Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
| | - Sura M. Ahmed
- Department of Electrical & Electronic Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
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Wu Y, Sun S, Liu Z, Wang S, Wang G, Zhao S, Wei R, Huang Y. Changes in asphericity of anterior and posterior corneal surfaces for mild–moderate and high myopia after topography-guided FS-LASIK. Int Ophthalmol 2022; 42:3555-3565. [DOI: 10.1007/s10792-022-02356-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
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Gharieb Ibrahim HM. Effect of Pharmacological Mydriasis on the Intraocular Pressure in Eyes with Filtering Blebs Compared to Normal Eyes: A Pilot Study. Clin Ophthalmol 2022; 16:231-237. [PMID: 35136349 PMCID: PMC8817738 DOI: 10.2147/opth.s348365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/17/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Hani M Gharieb Ibrahim
- Ophthalmology Department, Ain Shams University, Cairo, Egypt
- Correspondence: Hani M Gharieb Ibrahim, Ophthalmology Department, Ain Shams University Faculty of Medicine, Ramsees Street, Abbaseya, Cairo, Egypt, Email ;
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Gad RE, Hosny M, Ahmed RA, Sherif AM, Salah Eldin Y. Contralateral Eye Study of Topography Guided versus Q Value Adjusted Photorefractive Keratectomy in Myopia and Myopic Astigmatism. Clin Ophthalmol 2021; 15:1735-1749. [PMID: 33935490 PMCID: PMC8080117 DOI: 10.2147/opth.s300232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose of the Study To compare visual outcome, higher order aberrations (HOAs) of topography guided and Q value adjusted ablation in the fellow eye of patients undergoing photorefractive keratectomy (PRK) for the correction of myopia and myopic astigmatism. Methods Prospective randomized controlled interventional clinical study. The eyes of 52 patients undergoing PRK for myopia and astigmatism were included, that is, 104 eyes in total. In each patient, eyes were randomly allocated to group I: one eye received topography guided PRK using Contoura ablation software, or group II: the other eye received Q value adjusted PRK using Custom Q ablation software. Follow-Up Six months. Results At the end of 6 months, LogMAR UDVA was -0.04 ± 0.12 and -0.05 ± 0.11 (p = 0.688), while LogMAR CDVA was -0.06 ± 0.09 and -0.06 ± 0.1 in group I and group II, respectively (p = 0.972). Both groups showed a progressive oblate shift with time. This oblate shift was insignificantly less in group I by Topolyzer at 6mm, 15° and 30° at 6 months (p = 0.102, p = 0.138, p = 0.245, respectively). Topolyzer identified a significant difference between the change in coma and trefoil in both groups at 6 months (p<0.001 and p = 0.001, respectively). This was caused by the significant worsening of coma in group II (p<0.001) and the significant improvement of trefoil in group I (p = 0.007). No significant difference was found between groups in the change of ISV or ABR (p = 0.955 and 0.982, respectively). Ablation depth is a significant predictor of ΔQ at 6mm, 15° and 30° (p = 0.009, 0.039 and 0, respectively). No significant difference was found in the Strehl ratio or contrast sensitivity, although they were insignificantly better in group I (p = 0.785 and p = 0.745, respectively). Conclusion TG PRK and CQ PRK yielded similar results regarding UDVA, CDVA, MRSE, safety, predictability and contrast sensitivity. Both groups showed a progressive oblate shift, which was less in the TG group but the difference was statistically insignificant. TG PRK showed significantly improved trefoil HOA as compared to CQ PRK.
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Affiliation(s)
- Rania E Gad
- Ophthalmology Department, Helwan University, Cairo, Egypt
| | - Mohamed Hosny
- Ophthalmology Department, Cairo University, Cairo, Egypt
| | - Rania A Ahmed
- Ophthalmology Department, Cairo University, Cairo, Egypt
| | - Ahmed M Sherif
- Ophthalmology Department, Cairo University, Cairo, Egypt
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Group Analysis of Q Values Calculated with Tangential Radius of Curvature from Human Anterior Corneal Surface. J Ophthalmol 2018; 2018:7263564. [PMID: 29850210 PMCID: PMC5932450 DOI: 10.1155/2018/7263564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Objective To calculate the Q values from the human anterior corneal surface with the tangential radius of curvature and analyze its distribution characteristics in different age and refractive status groups. Methods Tangential power maps of the anterior cornea from Orbscan II were acquired for 201 subjects' right eyes. They were divided into groups of adults and children and then divided further into subgroups according to the refraction status. The Q values of each semimeridian were calculated by the tangential radius with a linear regression equation. The Q value distribution in both the nasal cornea and temporal cornea were analyzed. Results The mean temporal Q values of the emmetropia group of adults and all children's groups were significantly different from the mean nasal Q value. The mean nasal corneal Q values were more negative in children. The adult group showed differences only in the low myopia group. The mean Q value of the nasal cornea among different refractive groups of children was significantly different, and so was the temporal cornea between the adult myopia and emmetropia group. Conclusion The method using the tangential radius of curvature combined with linear regression to obtain anterior surface Q values for both adults and children was stable and reliable. When we analyzed the anterior corneal Q value, area division was necessary.
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Wang J, Ren Y, Liang K, Jiang Z, Tao L. Changes of corneal high-order aberrations after femtosecond laser-assisted in situ keratomileusis. Medicine (Baltimore) 2018; 97:e0618. [PMID: 29718869 PMCID: PMC6392645 DOI: 10.1097/md.0000000000010618] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Femtosecond laser-assisted in situ keratomileusis (FS-LASIK) has gained widespread popularity as a safe, effective and predictable treatment for correcting myopia and myopic astigmatism.However, complications such as biomechanical changes, structural weakness, dry eye and induction of high-order aberrations (HOAs) have been associated with FS laser excision. The induction of HOAs has been reported to reduce quality of vision, leading to increased glare, halos, starburst and deterioration of contrast function corneal HOAs play a significant role in whole-eye aberration. Thus, it is necessary to investigate the changes of corneal high-order aberrations after FS-LASIK. METHODS One hundred thirty-four eyes from 68 consecutive patients with myopia or myopic astigmatism were enrolled in this study. Corneal topography and visual acuity were measured preoperatively and at 1, 3, 6, and 12 months after FS-LASIK. Wavefront errors from the whole cornea, anterior cornea, and posterior cornea were measured by Pentacam. RESULTS Corneal aberrations on the posterior surface were less affected by FS-LASIK compared with those on the anterior surface and the whole cornea. The high-order aberrations (HOAs) on the whole and anterior corneal surfaces increased significantly at 1 month after surgery (P = .000, P = .000), while HOAs on the posterior surface did not significantly change (P = 1.000). The spherical aberration on the whole corneal and anterior corneal surfaces were significantly increased at 1 and 3 months postoperatively (P = .000 and P = .000, respectively), along with the vertical coma on the whole and anterior corneal surfaces at 1 and 3 months (P = .000 and P = .000, respectively). There was no significant difference in horizontal coma or trefoil on the whole, anterior and posterior corneal surfaces after surgery compared with preoperatively (all P = 1.000). CONCLUSION After FS-LASIK changes in corneal aberration occurred mainly on the anterior surface, which may have a significant effect on visual quality.
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Lin DTC, Holland SP, Verma S, Hogden J, Arba-Mosquera S. Postoperative Corneal Asphericity in Low, Moderate, and High Myopic Eyes After Transepithelial PRK Using a New Pulse Allocation. J Refract Surg 2017; 33:820-826. [PMID: 29227510 DOI: 10.3928/1081597x-20170920-02] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 08/25/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the postoperative asphericity in low, moderate, and high myopic eyes after combined transepithelial photorefractive keratectomy and SmartSurfACE treatment (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). METHODS In this retrospective case series, the outcomes of myopic SmartSurfACE were evaluated at 3 months postoperatively in 106 eyes and divided into low (less than -4.125 diopters [D]), moderate (-4.125 to -6.25 D), and high (more than -6.25 D) myopia groups. In all cases, standard examinations and preoperative and postoperative corneal topography (SCHWIND Sirius) were performed. The analysis comprised evaluating the change in asphericity versus planned correction, comparing expected and achieved postoperative asphericity for all eyes, and comparison of the three groups in terms of the preoperative and postoperatively expected and achieved asphericity. RESULTS At 3 months postoperatively, the low myopia group (n = 33) improved average negative asphericity (Q = -0.04 ± 0.17 preoperative vs -0.19 ± 0.20 postoperative, P < .05). The moderate myopia group (n = 35) maintained or slightly improved average negative asphericity (Q = -0.07 ± 0.14 preoperative vs -0.05 ± 0.24 postoperative, P = .35). For the high myopia group (n = 38), the eyes became more oblate compared to the preoperative status (Q = -0.09 ± 0.15 preoperative vs 0.62 ± 0.70 postoperative, P < .05). In terms of asphericity, the difference between the three groups was not statistically significant preoperatively (P > .10), but showed significant differences postoperatively (P < .007). The cohort's average preoperative corrected distance visual acuity was 0.01 ± 0.04 logMAR (range: 0.0 to 0.18 logMAR) and uncorrected distance visual acuity was 0.03 ± 0.08 logMAR (range: -0.12 to 0.40 logMAR) 3 months postoperatively. CONCLUSIONS SmartSurfACE maintained or slightly improved preoperative corneal asphericity for low to moderate myopic corrections (up to -6.00 D). This may provide advantages in the quality of vision and the onset of presbyopic symptoms after laser refractive surgery in myopic patients. [J Refract Surg. 2017;33(12):820-826.].
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Rey DV, Moreno-Montoya J. Resultado visual a los tres meses de cirugía con LASEK. REVISTA MEXICANA DE OFTALMOLOGÍA 2017. [DOI: 10.1016/j.mexoft.2016.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Xiong Y, Li J, Wang N, Liu X, Wang Z, Tsai FF, Wan X. The analysis of corneal asphericity (Q value) and its related factors of 1,683 Chinese eyes older than 30 years. PLoS One 2017; 12:e0176913. [PMID: 28545078 PMCID: PMC5436654 DOI: 10.1371/journal.pone.0176913] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 04/19/2017] [Indexed: 11/20/2022] Open
Abstract
Purpose To determine corneal Q value and its related factors in Chinese subjects older than 30 years. Design Cross sectional study. Methods 1,683 participants (1,683 eyes) from the Handan Eye Study were involved, including 955 female and 728 male with average age of 53.64 years old (range from 30 to 107 years). The corneal Q values of anterior and posterior surfaces were measured at 3.0, 5.0 and 7.0mm aperture diameters using Bausch & Lomb Orbscan IIz (software version 3.12). Age, gender and refractive power were recorded. Results The average Q values of the anterior surface at 3.0, 5.0 and 7.0mm aperture diameters were -0.28±0.18, -0.28±0.18, and -0.29±0.18, respectively. The average Q value of the anterior surface at the 5.0mm aperture diameter was negatively correlated with age (B = -0.003, p<0.01) and the refractive power (B = -0.013, p = 0.016). The average Q values of the posterior surface at 3.0, 5.0, and 7.0mm were -0.26±0.216, -0.26±0.214, and -0.26±0.215, respectively. The average Q value of the posterior surface at the 5.0mm aperture diameter was positively correlated with age (B = 0.002, p = 0.036) and the refractive power (B = 0.016, p = 0.043). Conclusion The corneal Q value of the elderly Chinese subjects is different from that of previously reported European and American subjects, and the Q value appears to be correlated with age and refractive power.
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Affiliation(s)
- Ying Xiong
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Jing Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Ophthalmology and Visual Science, Capital Medical University, Beijing, China
| | - Xue Liu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Ophthalmology and Visual Science, Capital Medical University, Beijing, China
| | - Zhao Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Frank F. Tsai
- Sharp Rees-Stealy Medical Group, San Diego, CA, United States of America
| | - Xiuhua Wan
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Ophthalmology and Visual Science, Capital Medical University, Beijing, China
- * E-mail:
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Khalifa MA, Alsahn MF, Shaheen MS, Pinero DP. Comparative analysis of the efficacy of astigmatic correction after wavefront-guided and wavefront-optimized LASIK in low and moderate myopic eyes. Int J Ophthalmol 2017; 10:285-292. [PMID: 28251090 DOI: 10.18240/ijo.2017.02.17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/11/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism using wavefront-guided (WFG) and wavefront-optimized (WFO) ablation profiles. METHODS Prospective study included 221 eyes undergoing LASIK: 99 and 122 eyes with low and moderate myopic astigmatism (low and moderate myopia groups). Two subgroups were differentiated in each group according to the ablation profile: WFG subgroup, 109 eyes (45/64, low/moderate myopia groups) treated using the Advanced CustomVue platform (Abbott Medical Optics Inc.), and WFO subgroup, 112 eyes (54/58, low/moderate myopia groups) treated using the EX-500 platform (Alcon). Clinical outcomes were evaluated during a 6-month follow-up, including a vector analysis of astigmatic changes. RESULTS Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group (P≤0.041). Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups (P≤0.003). In moderate myopia group, a higher percentage of eyes with a postoperative cylinder ≤0.25 D was found in the WFG subgroup (90.6% vs 65.5%, P=0.002). In low and moderate myopia groups, the difference vector was significantly higher in the WFO subgroup compared to WFG (P<0.001). In moderate myopia group, the magnitude (P=0.008) and angle of error (P<0.001) were also significantly higher in the WFO subgroup. Significantly less induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups (P≤0.006). CONCLUSION A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.
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Affiliation(s)
- Mounir A Khalifa
- Ophthalmology Department, Tanta University, Tanta 31527, Egypt; Horus Vision Correction Center, Alexandria 21311, Egypt; Alex LASIK Center, Alexandria 21311, Egypt
| | | | | | - David P Pinero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante 03690, Spain
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Molchan RP, Taylor KR, Panday VA, Caldwell MC, Reilly CD. Retrospective Analysis Comparing the Preoperative and Postoperative "Q" Values for 2 Different Lasers in Refractive Surgery. Cornea 2015; 34:1437-40. [PMID: 26356749 DOI: 10.1097/ico.0000000000000611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To compare the presurgical and postsurgical corneal asphericity, or "Q value," between VISX Wavefront-guided treatment and Allegretto Wave Wavefront-optimized treatment in photorefractive keratectomy for the correction of myopia. METHODS This is a retrospective database analysis performed at the Joint Warfighter Refractive Surgery Center, Lackland Air Force Base, TX. All data were accessed through the Institutional Review Board-approved Joint Warfighter Refractive Surgery Center database. Fifty-one patient records (102 eyes) were reviewed to determine the change in the Q value after photorefractive keratectomy for the correction of myopia. RESULTS The average change in the Q value per diopter of treatment sphere over the entire study population was 0.12 (±0.04) for Allegretto and 0.14 (±0.04) for VISX (P = 0.004). There was no statistical difference among the preoperative and postoperative best-corrected visual acuities (BCVAs), low-contrast BCVA (BCVA 5%), or quality of vision complaints between both platforms. CONCLUSIONS Low to moderate myopic correction with the Allegretto laser was associated with a smaller change in the Q value per diopter of treatment and therefore more closely maintained the original prolate shape of the cornea when compared with VISX. No difference in the postoperative visual outcome between both groups was detected.
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Affiliation(s)
- Ryan P Molchan
- *Joint Warfighter Refractive Surgery Center, Lackland AFB, TX; and †14th Medical Operations Squadron, Columbus AFB, MS
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Abstract
PURPOSE Our aim was to examine the influence of the Valsalva maneuver (VM) on corneal morphology and anterior chamber parameters. METHODS This prospective observational study included 35 eyes of 35 healthy volunteers. One of the eyes of each subject was selected randomly. The keratometry (K), pachymetry, corneal volume, iridocorneal angle, anterior chamber depth, anterior chamber volume, and corneal wave front measurements (high-order aberration, low-order aberration, total root mean square) were performed with the Pentacam HR (Oculus, Wetzlar, Germany). RESULTS The subjects were aged between 22 and 41 years. There were 24 men (69%) and 11 women (31%). The VM did not have any significant influence on K-flat and K-average values (P > 0.05), but it decreased K-steep values significantly (P = 0.006). The VM did not have any significant impact on low-order aberrations and total root mean square parameters (P > 0.05), but it increased high-order aberrations significantly (P = 0.008). The central corneal thickness and corneal volume decreased significantly during the VM (P < 0.05). The iridocorneal angle, anterior chamber depth, and anterior chamber volume decreased markedly during the VM (P < 0.001). CONCLUSIONS The VM has some influence on corneal morphology and anterior chamber parameters, so that it should be considered during anterior segment examinations and operations.
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