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Cheng X, Zhao Y, Fu D, Zhou X, Gao Y, Yu Z. Posterior corneal stability after small incision lenticule extraction with different optical zones. Eye (Lond) 2024:10.1038/s41433-024-03224-9. [PMID: 38997503 DOI: 10.1038/s41433-024-03224-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 05/16/2024] [Accepted: 07/04/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND To assess the changes in the posterior corneal surface following small incision lenticule extraction (SMILE) with different optical zones. METHODS In this retrospective study, 106 eyes of 106 patients who underwent SMILE were recruited 3 years after the procedure. Eyes were divided into two groups according to the size of the surgical optical zone: group A (52 eyes, ≤6.2 mm) and group B (54 eyes, ≥6.5 mm). Posterior central elevation (PCE) and 12 other points at 45°, 135°, 225° and 315° with distances of 1 mm, 2 mm and 3 mm from the centre were recorded from Pentacam. RESULTS No iatrogenic keratectasia was identified, and eyes in the two groups showed comparable visual results. The overall trend in posterior corneal elevation changes was consistent for both groups. PCE decreased significantly from 1.33 ± 2.32 to 0.75 ± 2.41 in group A (P = 0.024) and from 0.87 ± 2.61 to 0.06 ± 2.74 in group B (P = 0.003). All points in the central 2 mm region in both groups were reduced postoperatively. In the 4 mm and 6 mm corneal annulus, almost all points at 225°and 315° showed backward displacement, with the most prominent change occurring at 315° in the 6 mm annulus (P < 0.001), indicating no forward protrusion in the inferior area. CONCLUSIONS No forward protrusion in the posterior corneal surface was observed 3 years after SMILE with different optical zones. Comprehensive preoperative measurements are essential for ensuring corneal stability and avoiding iatrogenic keratectasia.
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Affiliation(s)
- Xueying Cheng
- Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
| | - Yu Zhao
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, NHC, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Dan Fu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, NHC, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, NHC, Shanghai, China
- Key Laboratory of Myopia and Related Eye Diseases, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Ying Gao
- Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China.
| | - Zhiqiang Yu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.
- Key Laboratory of Myopia and Related Eye Diseases, NHC, Shanghai, China.
- Key Laboratory of Myopia and Related Eye Diseases, Chinese Academy of Medical Sciences, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.
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Moshirfar M, Tukan AN, Bundogji N, Liu HY, McCabe SE, Ronquillo YC, Hoopes PC. Ectasia After Corneal Refractive Surgery: A Systematic Review. Ophthalmol Ther 2021; 10:753-776. [PMID: 34417707 PMCID: PMC8589911 DOI: 10.1007/s40123-021-00383-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/02/2021] [Indexed: 01/03/2023] Open
Abstract
INTRODUCTION The incidence of ectasia following refractive surgery is unclear. This review sought to determine the worldwide rates of ectasia after photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE) based on reports in the literature. METHODS A systematic review was conducted according to modified Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Publications were identified by a search of eight electronic databases for relevant terms between 1984 and 2021. Patient characteristics and preoperative values including manifest refractive spherical refractive equivalent (MRSE), central corneal thickness (CCT), anterior keratometry, postoperative residual stromal bed (RSB), and percent tissue altered (PTA) were summarized. In addition, annual rates of each refractive surgery were determined, and incidence of post-refractive ectasia for each type was calculated using the number of ectatic eyes identified in the literature. RESULTS In total, 57 eyes (70 eyes including those with preoperative risk factors for ectasia) were identified to have post-PRK ectasia, while 1453 eyes (1681 eyes including risk factors) had post-LASIK ectasia, and 11 eyes (19 eyes including risk factors) had post-SMILE ectasia. Cases of refractive surgery performed annually were estimated as 283,920 for PRK, 1,608,880 for LASIK, and 96,750 for SMILE. Reported post-refractive ectasia in eyes without preoperative identifiable risk factors occurred with the following incidences: 20 per 100,000 eyes in PRK, 90 per 100,000 eyes in LASIK, and 11 per 100,000 eyes in SMILE. The rate of ectasia in LASIK was found to be 4.5 times higher than that of PRK. CONCLUSION Post-refractive ectasia occurs at lower rates in eyes undergoing PRK than LASIK. Although SMILE appears to have the lowest rate of ectasia, the number of cases already reported since its recent approval suggests that post-SMILE ectasia may become a concern. Considering that keratoconus is a spectrum of disease, pre-existing keratoconus may play a larger role in postoperative ectasia than previously accounted for in the literature.
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Affiliation(s)
- Majid Moshirfar
- Hoopes Vision Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT, 84020, USA.
- John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Utah Lions Eye Bank, Murray, UT, USA.
| | - Alyson N Tukan
- University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Nour Bundogji
- University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Harry Y Liu
- McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Shannon E McCabe
- Hoopes Vision Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT, 84020, USA
- Mission Hills Eye Center, Pleasant Hill, CA, USA
| | - Yasmyne C Ronquillo
- Hoopes Vision Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT, 84020, USA
| | - Phillip C Hoopes
- Hoopes Vision Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT, 84020, USA
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Zhou W, Stojanovic F, Reinstein DZ, Archer TJ, Chen X, Feng Y, Stojanovic A. Coma Influence on Manifest Astigmatism in Coma-Dominant Irregular Corneal Optics. J Refract Surg 2021; 37:274-282. [PMID: 34038660 DOI: 10.3928/1081597x-20210119-02] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the influence of coma on manifest refractive cylinder (MRC) in eyes with coma-dominated corneal optics and suggest alternative guidelines for surgical planning of astigmatism correction in topography-guided ablation and toric intraocular lens (IOL) exchange surgery. METHODS Twelve eyes with coma-dominant corneal optics and low lenticular astigmatism were selected. The astigmatism remaining after subtraction of total corneal astigmatism (TCA) and lenticular astigmatism from MRC, termed discrepant astigmatism, was calculated and correlated to corneal coma at the anterior surface. Refractive and topography data were then used to simulate topography-guided refractive surgery (topography-guided group) in 7 eyes and lenticular exchange surgery with toric intraocular lens (IOL) implantation (toric IOL group) in 5 eyes. The estimated postoperative MRC after correction of TCA or MRC for each group was compared. RESULTS The axis and amplitude of discrepant astigmatism correlated strongly with the axis and amplitude of coma. In the topography-guided group, where topography-guided ablation eliminated corneal higher order aberrations (HOAs), TCA-based correction led to less estimated postoperative manifest astigmatism than MRC-based correction. In the toric IOL group, where removal of the crystalline lens did not affect corneal HOAs, MRC-based correction via toric IOL implantation led to less estimated postoperative astigmatism than TCA-based correction. CONCLUSIONS Discrepant astigmatism in eyes with coma-dominant corneal optics correlates with coma. In such eyes, treating TCA, along with corneal HOAs, instead of MRC, seems appropriate in topography-guided treatments, whereas treating MRC may be a better choice in lenticular exchange surgery with toric IOL implantation, where corneal HOAs are not treated. [J Refract Surg. 2021;37(4):274-282.].
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The contribution of ocular residual astigmatism to anterior corneal astigmatism in refractive astigmatism eyes. Sci Rep 2021; 11:1018. [PMID: 33441809 PMCID: PMC7806660 DOI: 10.1038/s41598-020-80106-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/14/2020] [Indexed: 11/08/2022] Open
Abstract
To determine the distribution of ocular residual astigmatism (ORA) in astigmatic eyes and the influence on the anterior corneal (ACA) and refractive astigmatism (RA). A total of 165 children met the inclusion criteria. Right eyes' data were analyzed. Using Thibos vector analysis to calculate ORA. Spearman correlation analysis was used to obtain the correlation between the magnitude of ORA, ACA and RA. The median magnitude of ORA in astigmatic eyes was 0.57 D, with interquartile range was 0.42 D. And they were main against-the-rule (57.6-75.8%) and oblique astigmatism (13.9-34.5%) ORA. The ORA in 140 eyes (84.8%) acted as an offset to ACA, meanwhile, 25 eyes (15.2%) superimposed it. About 98% (97.9-98.4%) against-the-rule and 75% (73.9-82.5%) oblique ORA counteracted ACA, nevertheless, all with-the-rule ORA had a superimposed effect on ACA. For with-the-rule ACA, about 86% (85.4-85.9%) ORA worked to offset it. There was statistically correlations between ORA and ACA (r = 0.17, P = 0.03), ORA and RA (r = - 0.27, P = 0.001). The magnitude of ocular residual astigmatism was relatively small in children's astigmatic eyes. Both against-the-rule and oblique ORA can counteract with-the-rule ACA.
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Hernández-Rodríguez CJ, Piñero DP. A systematic review about the impact of phakic intraocular lenses on accommodation. JOURNAL OF OPTOMETRY 2020; 13:139-145. [PMID: 31937486 PMCID: PMC7301210 DOI: 10.1016/j.optom.2019.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 07/26/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Phakic intraocular lenses (pIOL) are the main treatment for patients who have either high ametropia or contraindications for laser refractive surgery. The main feature that makes this kind of lenses suitable for its implantation in young adults searching for independence of optical prescription is the conservation of accommodation, since lens extraction is not required. A systematic review has been performed to evaluate the scientific literature on the effect of pIOL implantation on accommodation. Critical assessment of the articles included in the review was achieved using the tool Critical Appraisal Skills Programme in its Spanish form (CASPe). After revising the complete text of 10 articles pre-selected, two quasi-experimental pre-post studies evaluating the outcomes of a specific model of posterior chamber pIOL were included in the systematic review. The CASPe scoring of both studies were 5/11. According to this outcome, the evidence describing the impact of the pIOL implantation on the accommodative function can be defined poor. Some trends are reported as the decrease in the amplitude of accommodation, a decrease positive relative accommodation and improvement of accommodation. However, these results should be confirmed in future controlled studies.
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Affiliation(s)
- Carlos J Hernández-Rodríguez
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - David P Piñero
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain.
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Peris-Martínez C, Bueno-Gimeno I, Alvarez-Arana I, Piñero DP, Gené-Sampedro A. Characterization of the effect of intracorneal ring segment in corneal ectasia after laser refractive surgery. Eur J Ophthalmol 2018; 30:125-131. [PMID: 30384777 DOI: 10.1177/1120672118808968] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate the visual, refractive, topographic, pachymetric, and biomechanical outcomes after intracorneal ring segment implantation in corneas with post-LASIK ectasia. METHODS Retrospective longitudinal study enrolling 26 eyes of 22 patients with post-LASIK ectasia and undergoing intracorneal ring segment implantation (KeraRing®, Mediphacos) using a 60-kHz femtosecond laser (IntraLase®, IntraLase Corp.) for corneal tunnelization. Visual, refractive, anterior, and posterior corneal topographic (Pentacam HR, Oculus), pachymetric, and corneal biomechanical changes (Ocular response Analyzer, Reichert) were evaluated during a 12-month follow-up. Vector analysis of astigmatic changes was performed. RESULTS A statistically significant reduction of sphere (p = 0.043) was observed at 1 month after surgery, with a significant improvement of uncorrected distance visual acuity associated (p = 0.019). Likewise, a significant reduction of anterior corneal power measurements (p ⩽ 0.014) and steepest posterior keratometric reading (p = 0.006) were observed at 1 month postoperatively, with no significant changes afterwards (p ⩾ 0.133). No significant changes were observed in manifest cylinder (p ⩾ 0.175), corrected distance visual acuity (p ⩾ 0.174), flattest posterior keratometric measurement (p ⩾ 0.282), volumetric measurements (p ⩾ 0.051), and corneal biomechanical parameters (p ⩾ 0.068). Vector analysis revealed an initial trend to overcorrection of astigmatism, with a trend to undercorrection at the end of follow-up and a significant variability in the outcome achieved in each patient. CONCLUSION The implantation of KeraRing segments in post-LASIK corneal ectasia generates a significant modification of spherical refraction and a visual improvement due to a central corneal flattening generated. More refined nomograms of implantation in these cases should be developed to achieve a more predictable correction of astigmatism.
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Affiliation(s)
- Cristina Peris-Martínez
- FISABIO Oftalmología Médica (FOM), Cornea and External Diseases Unit, Valencia, Spain.,Aviño&Peris Eye Clinic, Valencia, Spain
| | - Inmaculada Bueno-Gimeno
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Valencia, Spain
| | - Izaskun Alvarez-Arana
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Valencia, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Andrés Gené-Sampedro
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Valencia, Spain.,Research Institute on Traffic and Road Safety (INTRAS) University of Valencia, Valencia, Spain
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Abstract
PURPOSE To report the refractive, topographic, tomographic, and aberrometric characteristics of post-LASIK ectasia; to compare these characteristics with normal post-LASIK controls; and to propose a comprehensive system to grade the severity of post-LASIK ectasia. METHODS The refraction, corrected distance visual acuity (CDVA), magnitude, and location of the steepest and thinnest point on the cornea, the highest anterior and posterior surface elevation, the radius of best fit sphere, corneal asphericity, and corneal aberrations were measured in 50 eyes of 29 patients with post-LASIK ectasia. These were compared with corresponding parameters in 50 eyes that did not develop ectasia for more than 1 year after LASIK. A logistic regression analysis was used to create a scoring system to grade the severity. RESULTS Eyes with post-LASIK ectasia had significantly higher myopia with astigmatism and a lower CDVA than control eyes. Mean topographic toricity was 3.4 ± 1.9D, mean keratometry at the steepest point was 55.32 ± 6.63D, mean highest posterior elevation was 69.72 ± 3 μm, and mean coma was -2.06 ± 1.2 μm. All these parameters were significantly higher than corresponding values in the control group (p < 0.001 in all). Spherical aberration was more negative and the change in asphericity indicated significantly greater prolate shape of the cornea in eyes with post-LASIK ectasia compared to controls. Five parameters, namely, CDVA, spherical equivalent, highest posterior corneal elevation, spherical aberration, and corneal asphericity, were identified as significant predictors of post-LASIK ectasia and used to create a scoring system. CONCLUSION Post-LASIK ectasia is characterized by significant changes in refraction, topography, tomography, and aberrometry. The proposed scoring system may be useful in diagnosing, grading, and monitoring post-LASIK ectasia.
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Zhou W, Stojanovic A, Utheim TP. Assessment of refractive astigmatism and simulated therapeutic refractive surgery strategies in coma-like-aberrations-dominant corneal optics. EYE AND VISION 2016; 3:13. [PMID: 27175371 PMCID: PMC4864917 DOI: 10.1186/s40662-016-0044-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 04/21/2016] [Indexed: 12/03/2022]
Abstract
Background The aim of the study is to raise the awareness of the influence of coma-like higher-order aberrations (HOAs) on power and orientation of refractive astigmatism (RA) and to explore how to account for that influence in the planning of topography-guided refractive surgery in eyes with coma-like-aberrations-dominant corneal optics. Methods Eleven eyes with coma-like-aberrations-dominant corneal optics and with low lenticular astigmatism (LA) were selected for astigmatism analysis and for treatment simulations with topography-guided custom ablation. Vector analysis was used to evaluate the contribution of coma-like corneal HOAs to RA. Two different strategies were used for simulated treatments aiming to regularize irregular corneal optics: With both strategies correction of anterior corneal surface irregularities (corneal HOAs) were intended. Correction of total corneal astigmatism (TCA) and RA was intended as well with strategies 1 and 2, respectively. Results Axis of discrepant astigmatism (RA minus TCA minus LA) correlated strongly with axis of coma. Vertical coma influenced RA by canceling the effect of the with-the-rule astigmatism and increasing the effect of the against-the-rule astigmatism. After simulated correction of anterior corneal HOAs along with TCA and RA (strategies 1 and 2), only a small amount of anterior corneal astigmatism (ACA) and no TCA remained after strategy 1, while considerable amount of ACA and TCA remained after strategy 2. Conclusions Coma-like corneal aberrations seem to contribute a considerable astigmatic component to RA in eyes with coma-like-aberrations dominant corneal optics. If topography-guided ablation is programmed to correct the corneal HOAs and RA, the astigmatic component caused by the coma-like corneal HOAs will be treated twice and will result in induced astigmatism. Disregarding RA and treating TCA along with the corneal HOAs is recommended instead.
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Affiliation(s)
- Wen Zhou
- SynsLaser Kirurgi AS, Tromsø, Troms Norway ; School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Aleksandar Stojanovic
- SynsLaser Kirurgi AS, Tromsø, Troms Norway ; Eye Department, University Hospital North Norway, Tromsø, Norway
| | - Tor Paaske Utheim
- Department of Ophthalmology, Vestre Viken Hospital Trust, Drammen, Norway ; Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway ; Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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Piñero DP, Pérez-Cambrodí RJ, Soto-Negro R, Ruiz-Fortes P, Artola A. Clinical utility of ocular residual astigmatism and topographic disparity vector indexes in subclinical and clinical keratoconus. Graefes Arch Clin Exp Ophthalmol 2015; 253:2229-37. [DOI: 10.1007/s00417-015-3169-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 08/19/2015] [Accepted: 08/27/2015] [Indexed: 10/23/2022] Open
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Archer TJ, Reinstein DZ, Piñero DP, Gobbe M, Carp GI. Comparison of the predictability of refractive cylinder correction by laser in situ keratomileusis in eyes with low or high ocular residual astigmatism. J Cataract Refract Surg 2015; 41:1383-92. [DOI: 10.1016/j.jcrs.2014.10.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 09/30/2014] [Accepted: 10/11/2014] [Indexed: 11/16/2022]
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Influence of the difference between corneal and refractive astigmatism on LASIK outcomes using solid-state technology. Cornea 2014; 33:1287-94. [PMID: 25321937 DOI: 10.1097/ico.0000000000000272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the influence of the difference between preoperative corneal and refractive astigmatism [ocular residual astigmatism (ORA)] on outcomes obtained after laser in situ keratomileusis (LASIK) surgery for correction of myopic astigmatism using the solid-state laser technology. METHODS One hundred one consecutive eyes with myopia or myopic astigmatism of 55 patients undergoing LASIK surgery using the Pulzar Z1 solid-state laser (CustomVis Laser Pty Ltd, currently CV Laser) were included. Visual and refractive changes at 6 months postoperatively and changes in ORA and anterior corneal astigmatism and posterior corneal astigmatism (PCA) were analyzed. RESULTS Postoperatively, uncorrected distance visual acuity improved significantly (P < 0.01). Likewise, refractive cylinder magnitude and spherical equivalent were reduced significantly (P < 0.01). In contrast, no significant changes were observed in ORA magnitude (P = 0.81) and anterior corneal astigmatism (P = 0.12). The mean overall efficacy and safety indices were 0.96 and 1.01, respectively. These indices were not correlated with preoperative ORA (r = -0.15, P = 0.15). Furthermore, a significant correlation was found between ORA (r = 0.81, P < 0.01) and PCA postoperatively, but not preoperatively (r = 0.12, P = 0.25). Likewise, a significant correlation of ORA with manifest refraction was only found postoperatively (r = -0.38, P < 0.01). CONCLUSIONS The magnitude of ORA does not seem to be a predictive factor of efficacy and safety of myopic LASIK using a solid-state laser platform. The higher relevance of PCA after surgery in some cases may explain the presence of unexpected astigmatic residual refractive errors.
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Peña-García P, Alió JL, Vega-Estrada A, Barraquer RI. Internal, corneal, and refractive astigmatism as prognostic factors for intrastromal corneal ring segment implantation in mild to moderate keratoconus. J Cataract Refract Surg 2014; 40:1633-44. [DOI: 10.1016/j.jcrs.2014.01.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/18/2013] [Accepted: 01/07/2014] [Indexed: 12/26/2022]
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In vivo characterization of corneal biomechanics. J Cataract Refract Surg 2014; 40:870-87. [DOI: 10.1016/j.jcrs.2014.03.021] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 11/22/2022]
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Piñero DP, Ruiz-Fortes P, Pérez-Cambrodí RJ, Mateo V, Artola A. Ocular residual astigmatism and topographic disparity vector indexes in normal healthy eyes. Cont Lens Anterior Eye 2013; 37:49-54. [PMID: 23910507 DOI: 10.1016/j.clae.2013.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/20/2013] [Accepted: 07/04/2013] [Indexed: 11/26/2022]
Abstract
PURPOSE To define a range of normality for the vectorial parameters Ocular Residual Astigmatism (ORA) and topography disparity (TD) and to evaluate their relationship with visual, refractive, anterior and posterior corneal curvature, pachymetric and corneal volume data in normal healthy eyes. METHODS This study comprised a total of 101 consecutive normal healthy eyes of 101 patients ranging in age from 15 to 64 years old. In all cases, a complete corneal analysis was performed using a Scheimpflug photography-based topography system (Pentacam system Oculus Optikgeräte GmbH). Anterior corneal topographic data were imported from the Pentacam system to the iASSORT software (ASSORT Pty. Ltd.), which allowed the calculation of the ocular residual astigmatism (ORA) and topography disparity (TD). Linear regression analysis was used for obtaining a linear expression relating ORA and posterior corneal astigmatism (PCA). RESULTS Mean magnitude of ORA was 0.79 D (SD: 0.43), with a normality range from 0 to 1.63D. 90 eyes (89.1%) showed against-the-rule ORA. A weak although statistically significant correlation was found between the magnitudes of posterior corneal astigmatism and ORA (r=0.34, p<0.01). Regression analysis showed the presence of a linear relationship between these two variables, although with a very limited predictability (R(2): 0.08). Mean magnitude of TD was 0.89D (SD: 0.50), with a normality range from 0 to 1.87D. CONCLUSION The magnitude of the vector parameters ORA and TD is lower than 1.9D in the healthy human eye.
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Affiliation(s)
- David P Piñero
- Ocular Surface and Cornea Unit, Department of Ophthalmology, Oftalmar, Hospital Internacional Medimar, Alicante, Spain; Foundation for the Visual Quality (FUNCAVIS, Fundación para la Calidad Visual), Alicante, Spain; Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain.
| | - Pedro Ruiz-Fortes
- Ocular Surface and Cornea Unit, Department of Ophthalmology, Oftalmar, Hospital Internacional Medimar, Alicante, Spain
| | - Rafael J Pérez-Cambrodí
- Ocular Surface and Cornea Unit, Department of Ophthalmology, Oftalmar, Hospital Internacional Medimar, Alicante, Spain; Foundation for the Visual Quality (FUNCAVIS, Fundación para la Calidad Visual), Alicante, Spain
| | - Verónica Mateo
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - Alberto Artola
- Ocular Surface and Cornea Unit, Department of Ophthalmology, Oftalmar, Hospital Internacional Medimar, Alicante, Spain
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Goggin M. Internal astigmatism and ocular residual astigmatism. J Cataract Refract Surg 2012; 38:381-2; author reply 382. [DOI: 10.1016/j.jcrs.2011.11.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Indexed: 10/14/2022]
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