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Haidari H, Derhartunian V, Arba-Mosquera S. Method to determine the centration of a lenticule of tissue extracted from a cornea. BIOMEDICAL OPTICS EXPRESS 2023; 14:4080-4096. [PMID: 37799703 PMCID: PMC10549739 DOI: 10.1364/boe.495416] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 10/07/2023]
Abstract
A simple and novel method to analyse the centration of a lenticule of tissue extracted from a cornea has been developed, in which the centre of "mass" of the individual differences between post and preoperative maps of several corneal metrics represents the lenticule centration and its spatial distance to a reference point (aimed centration) determines the decentration. Different parameters have been evaluated to weight the centre of "mass". The robustness of the methods has been evaluated using perturbation analysis (adding white-noise to the data) based on realistic uncertainties. A clipped analysis has been performed to prevent large, localised areas of lacking/missing data from affecting the centre of "mass". The method has been tested on a pilot cohort of clinical data showing 30% and 63% of the treatments within 200 µm of decentration for corneal thickness and refractive equivalent power, respectively. Except for anterior elevation with a total standard deviation of 17 µm, all other metrics show excellent precision of ∼5 µm. The method provides a reliable and objective way to determine the centration of a lenticule of tissue extracted from a cornea and it can be applied to any topo- or tomographic derived metric.
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Affiliation(s)
- Hamed Haidari
- Technische Hochschule Aschaffenburg University of Applied Sciences (student), Aschaffenburg, D- 63743, Germany
- SCHWIND eye-tech-solutions, Kleinostheim, D- 63801, Germany
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Liu Z, Zhao Y, Sun S, Wu Y, Wang G, Zhao S, Huang Y. Effect of preoperative pupil offset on corneal higher-order aberrations after femtosecond laser-assisted in situ keratomileusis. BMC Ophthalmol 2023; 23:247. [PMID: 37264322 DOI: 10.1186/s12886-023-02960-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 05/04/2023] [Indexed: 06/03/2023] Open
Abstract
BACKGROUND This study aimed to investigate the relationship between multiple higher-order aberrations (HOAs) subgroups and pupil offset, as well as to analyze the factors affecting postoperative corneal HOAs in patients with different degrees of refractive errors. METHODS We enrolled 160 patients (316 eyes) aged ≥ 18 years who had undergone femtosecond laser-assisted in situ keratomileusis (FS-LASIK) treatment. Based on the relationship between the preoperative pupil offset and the postoperative ΔHOAs, all patients were divided into two groups: group I (pupil offset ≤ 0.20 mm) and group II (pupil offset > 0.20 mm). All of the eyes had low to high myopia with or without astigmatism (manifest refraction spherical equivalent (MRSE) < -10.00 D). Uncorrected distance visual acuity, corrected distance visual acuity, MRSE, pupil offset, central corneal thickness, corneal HOAs, vertical coma (Z3-1), horizontal coma (Z31), spherical aberration (Z40), trefoil 0° (Z33), and trefoil 30° (Z3-3) over a 6 mm diameter central corneal zone diameter were evaluated preoperatively and at 1 and 3 months postoperatively. RESULTS Our result revealed significant differences in postoperative corneal total root mean square (RMS) HOAs, RMS vertical coma, RMS horizontal coma, RMS spherical aberration, and RMS trefoil 30° between group I and group II. ΔMRSE was found to be an effective factor for ΔRMS HOAs (R2 = 0.383), ΔRMS horizontal coma (R2 = 0.205), and ΔRMS spherical aberration (R2 = 0.397). In group II, multiple linear regression analysis revealed a significant correlation between preoperative pupillary offset and Δtotal RMS HOAs (R2 = 0.461), ΔRMS horizontal coma (R2 = 0.040), and ΔRMS trefoil 30°(R2 = 0.089). The ΔRMS vertical coma effect factor is the Y-component, and the factor influencing ΔRMS spherical aberration was ΔMRSE (R2 = 0.256). CONCLUSION A small pupil offset was associated with a lower induction of postoperative corneal HOAs. Efforts to optimize centration are critical for improving surgical outcomes in patients with FS-LASIK.
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Affiliation(s)
- Zhanglin Liu
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China
| | - Yang Zhao
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China
| | - Shengshu Sun
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China
| | - Yuan Wu
- Aier Eye Hospital, Shanxi, 030006, China
| | - Guiqin Wang
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China
| | - Shaozhen Zhao
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China
| | - Yue Huang
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin, 300384, China.
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Cheng W, Li L, Luo G, Wang Y. Using a smartphone app in the measurement of posture-related pupil center shift on centration during corneal refractive surgery. Front Cell Dev Biol 2023; 11:1174122. [PMID: 37123406 PMCID: PMC10133467 DOI: 10.3389/fcell.2023.1174122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 04/04/2023] [Indexed: 05/02/2023] Open
Abstract
Purpose: Pupil center is an important anchor point in corneal refractive surgery, which may affect by body position. This study investigated the feasibility of using a smartphone application in measurement of posture-related pupil center shifts. Methods: Images of undilated eyes were captured for 25 participants (age: 18-38 years) at a distance of 40 cm in four body positions (seated, supine, right lateral, and left lateral) under controlled lighting conditions. During taking images, a smartphone application was used to guide positioning without head rotation and tilt. From the images, the location of the pupil center and pupil diameter with respect to the limbus boundary were measured. Results: According to the data obtained by the smartphone application, pupil center was located slightly nasal and superior to the limbus center in the seated position, and it shifted more nasally and superiorly (p < 0.001, OD 0.54 ± 0.11 mm, OS 0.57 ± 0.14 mm) in the supine position. When body position switched between left and right lateral positions, the pupil centers of both eyes shifted along the direction of gravity (p < 0.05), and no significant shift occurred along the longitudinal axis. Moreover, pupil constriction was observed when the body position changed from seated to supine position (p < 0.001, OD 0.64 ± 0.57 mm, OS 0.63 ± 0.58 mm). Conclusion: Posture-related pupil center shift may be larger than the error tolerance of centration in corneal refractive surgery, which might be difficult to measure by the existing instruments. An accessible application is necessary for evaluating the shift of pupil center and guiding centration during the surgery.
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Affiliation(s)
- Wenbo Cheng
- Department of Ophthalmology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Li Li
- Department of Ophthalmology, Fujian Provincial Hospital South Branch, Fujian Provincial Hospital, Fuzhou, Fujian, China
| | - Gang Luo
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Yan Wang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Nankai University, Tianjin, China
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Liang C, Yan H. Methods of Corneal Vertex Centration and Evaluation of Effective Optical Zone in Small Incision Lenticule Extraction. Ophthalmic Res 2023; 66:717-726. [PMID: 36917962 DOI: 10.1159/000529922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 02/20/2023] [Indexed: 03/16/2023]
Abstract
Inappropriate small incision lenticule extraction (SMILE) centration methods can affect the decentration of the effective optical zone (EOZ) after operation, which can subsequently lead to the decline of postoperative visual quality. We aimed to provide an overview of corneal vertex (CV) centration methods and an evaluation of the size and decentration of the EOZ in SMILE. We described the CV centration methods for patients with myopia, myopic astigmatism, hyperopia, and large kappa angle. The measurement methods of the EOZ were evaluated from the aspects of corneal morphology and corneal refractive power. Additionally, we summarized the advantages and disadvantages of measuring decentration based on topographic mapping and intraoperative video-captured images. Finally, we discussed the relationship between the EOZ and visual quality. Based on our review, clinicians should consider the following when choosing CV centration methods and evaluating EOZ postoperatively. First, the tear film mark center or topographic map comparison method is preferred for the correction of myopia, low myopic astigmatism, hyperopia, and large kappa angle (>0.2 mm). Triple marking centration is recommended for high myopic astigmatism (-3.5 diopters). Second, the total corneal power better reflects the change in refractive power than the topographic method. The measurement of the area rather than the diameter of the total corneal refractive power is more suitable for the evaluation of noncircular EOZs after high myopia astigmatism (<-2.0 diopters). Third, for the evaluation of decentration, the tangential curvature difference map method is preferred as it is not influenced by offset pupils. Finally, a large EOZ after SMILE may improve patient tolerance to decentration.
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Affiliation(s)
- Chen Liang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China,
- Department of Ophthalmology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China,
| | - Hong Yan
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
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Comparative study of refractive and visual quality after wavefront-optimized FS-LASIK for angle kappa adjustment in dominant and nondominant eyes. J Cataract Refract Surg 2023; 49:184-189. [PMID: 36026702 DOI: 10.1097/j.jcrs.0000000000001050] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 08/18/2022] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate the differences between dominant and nondominant eyes in femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) with 50% angle kappa compensation on diopter and visual quality. SETTING University hospital. DESIGN Retrospective clinical study. METHODS 109 patients (218 eyes, 100%) with myopia who underwent FS-LASIK were randomly selected. The preoperative pupil size, center position, and offset between the coaxially sighted corneal light reflex ( P-Dist ) of the patients was recorded. In preoperative and postoperative 6 months, an iTrace wavefront aberrometer was used to measure the corneal, internal optics, and total aberrations. RESULTS The 6 months postoperatively for corneal coma of the dominant eyes were 0.141 ± 0.055 μm and the nondominant eyes were 0.157 ± 0.033 μm, which was significantly greater than the dominant eyes ( P = .028). The postoperative corneal coma aberration changes were positively correlated with preoperative P-Dist , the dominant eyes ( r = 0.221, P = .023), and the nondominant eyes ( r = 0.251, P = .009). CONCLUSIONS Adjusting the angle kappa percentage in the nondominant eyes to be higher than that of the dominant eyes in individualized corneal refractive surgery may help find the ablation center closest to the visual axis.
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Reliability and agreement of apparent chord mu measurements between static and dynamic evaluations. J Cataract Refract Surg 2023; 49:21-28. [PMID: 36573762 DOI: 10.1097/j.jcrs.0000000000001036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/26/2022] [Indexed: 12/28/2022]
Abstract
PURPOSE To assess the repeatability and agreement of Cartesian coordinates and the length of apparent chord mu and pupil diameter measurements during static (Galilei G4) and dynamic (Topolyzer Vario) evaluations. SETTING IOBA-Eye Institute, Valladolid, Spain. DESIGN Case series. METHODS 3 consecutive measurements per scenario (Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions) were performed by the same clinician. The intrasession repeatability was assessed using the within-subject SD (Sw), the precision, the coefficient of variation, and the intraclass correlation coefficient (ICC). The agreement was analyzed using repeated-measures analysis of variance and the Bland-Altman method. RESULTS Thirty-seven healthy participants were recruited. The Sw values for chord mu parameters and pupil diameter ranged from 0.01 to 0.03 and 0.08 to 0.21, respectively. The ICC was ≥0.89 for all parameters. Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions provided significantly different measures of apparent chord mu length (0.23 ± 0.11 mm, 0.30 ± 0.10 mm, and 0.25 ± 0.11 mm, respectively, P ≤ .02), X-coordinate (-0.18 ± 0.12 mm, -0.27 ± 0.11 mm, and -0.21 ± 0.12 mm, respectively, P < .001), and pupil diameter (3.38 ± 0.50 mm, 6.29 ± 0.60 mm, and 3.04 ± 0.41 mm, respectively, P < .001). Y-coordinate values obtained by Galilei G4 and Topolyzer Vario under low mesopic conditions were significantly different (0.06 ± 0.13 mm vs 0.03 ± 0.11 mm, respectively, P = .02), in contrast to Galilei G4 and Topolyzer Vario under photopic conditions (0.05 ± 0.13 mm, P = .82) and both illumination conditions of Topolyzer Vario (P ≥ .23). CONCLUSIONS Galilei G4 and Topolyzer Vario provide consistent measurements of apparent chord mu Cartesian coordinates and length, as well as pupil diameter; however, the measurements are not interchangeable. Ophthalmic surgeons should consider these findings when planning customized intraocular lens implantation and refractive surgery procedures.
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Sun L, Lin HN, Jhanji V, Ng TK, Ji RF, Zhang R. Changes in effective optical zone after small-incision lenticule extraction in high myopia. Int Ophthalmol 2022; 42:3703-3711. [PMID: 35781597 DOI: 10.1007/s10792-022-02367-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/28/2022] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate the four measurement approaches on the determination of effective optical zone (EOZ) using Scheimpflug tomography after small-incision lenticule extraction surgery in eyes with high myopia. SETTING Corneal refractive surgery conducted in an eye hospital in southern China. DESIGN This is a retrospective cohort study. METHODS In total, 74 subjects were recruited. EOZ was measured at 3 months postoperatively using vertex-based (EOZV), pupil-based (EOZP), 4 mm-ring-based total corneal refraction method (EOZ4) and tangential curvature difference map method (EOZD), and their consistencies were compared. EOZs and planned optical zone (POZ) were compared and analyzed with eccentricity, ablation degree (AD) and total corneal aberrations. RESULTS At 3 months after surgery, the mean root mean square of ΔHOA, ΔComa, ΔTrefoil and ΔSA were 0.53 ± 0.27 μm, 0.36 ± 0.20 μm, 0.01 ± 0.84 μm and 0.16 ± 0.14 μm, respectively. EOZV, EOZP, EOZ4 and EOZD were 5.87 ± 0.44 mm, 5.85 ± 0.45 mm, 4.78 ± 0.40 mm and 5.29 ± 0.27 mm, respectively, which were significantly smaller than POZ 6.48 ± 0.16 mm. Bland-Altman plots showed a good consistency among the four EOZs. The difference between the EOZV and EOZP was 0.02 mm within the range of clinically acceptable difference. In addition, the eccentricity was positively correlated with ΔHOA, ΔComa and ΔSA. CONCLUSIONS All 4 measurement approaches demonstrated the reduction of EOZs compared to POZ. The EOZV was the closest to POZ, followed by EOZP. The ΔEOZs showed no significant difference with eccentricity, AD and corneal aberrations.
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Affiliation(s)
- Lixia Sun
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Hui-Ni Lin
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Vishal Jhanji
- Shantou University Medical College, Shantou, Guangdong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Department of Ophthalmology, UPMC Eye Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
- Shantou University Medical College, Shantou, Guangdong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Rui-Feng Ji
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Riping Zhang
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
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Reinstein DZ, Archer TJ, Rowe EL, Gobbe M, Vida RS. Distribution of Pupil Offset and Angle Kappa in a Refractive Surgery Preoperative Population of 750 Myopic, Emmetropic, and Hyperopic Eyes. J Refract Surg 2021; 37:49-58. [PMID: 33432995 DOI: 10.3928/1081597x-20201109-01] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/13/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To report the distribution of pupil offset and angle kappa in 750 myopic, emmetropic, and hyperopic eyes presenting for refractive surgery. METHODS A retrospective study included 750 consecutive eyes screened for corneal refractive surgery between January 2006 and February 2013. The eyes were divided into three equal groups based on manifest refraction spherical equivalent (SEQ): emmetropic group between -0.25 and +0.50 diopters (D) and cylinder up to 1.00 D, myopic group greater than -0.50 D, and hyperopic group greater than +0.50 D. Angle kappa was measured with the Orbscan II software (Bausch & Lomb, Inc) and pupil offset defined as the distance at the corneal plane between the corneal vertex and the pupil center. Correlations with SEQ, cylinder, scotopic pupil diameter, average keratometry, and age were performed. RESULTS All results are reported for myopic, emmetropic, and hyperopic groups, respectively. Mean SEQ was -4.84 ± 2.89 D (range: -0.88 to -14.00 D), +0.21 ± 0.23 D (range: -0.25 to +0.50 D), and +2.44 ± 1.58 D (range: +0.63 to +7.75 D). Mean pupil offset magnitude was 0.27 ± 0.14 mm (range: 0.00 to 0.68 mm), 0.34 ± 0.14 mm (range: 0.02 to 0.78 mm), and 0.39 ± 0.13 mm (range: 0.07 to 0.75 mm). Mean pupil offset X-component was -0.18 ± 0.18, -0.28 ± 0.16, and -0.34 ± 0.15 mm (temporally displaced from the corneal vertex). Mean pupil offset Y-component was 0.06 ± 0.15, 0.03 ± 0.16, and 0.01 ± 0.16 mm (superiorly displaced from the corneal vertex). Multivariate linear regression for pupil offset magnitude found statistically significant variables were SEQ, cylinder, scotopic pupil diameter, and average keratometry. For pupil offset X-component, significant variables were SEQ, cylinder, and scotopic pupil diameter. For pupil offset Y-component, significant variables were SEQ and scotopic pupil diameter. Mean angle kappa was 5.28 ± 1.49°, 6.14 ± 1.44°, and 5.77 ± 1.29°. CONCLUSIONS Contrary to common belief, a pupil offset is present in the vast majority of eyes regardless of refractive error, with the mean temporal offset of at least 0.18 mm. Confirming previous studies, the largest pupil offset was found in the hyperopic group. However, there was also a wide range of pupil offset in myopic and emmetropic eyes. Correlations with SEQ and keratometry support the theory that pupil offset is also correlated with axial length. [J Refract Surg. 2021;37(1):49-58.].
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Comparison of effective corneal refractive centration to the visual axis: LASIK vs. SMILE, a contralateral eye digitized comparison of the postoperative result. J Cataract Refract Surg 2021; 47:1511-1518. [PMID: 34074993 DOI: 10.1097/j.jcrs.0000000000000687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 04/24/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE To define and compare the centration of the ablation effect in LASIK to the corresponding effect in SMILE, in myopic laser vision correction in order to possibly explain the refractive performance differences noted between the two procedures in a contralateral eye study. SETTING Private Ambulatory Eye Surgery Unit. DESIGN Prospective randomized contralateral eye study. METHODS In 22 consecutive patients (44 eyes), one eye was prospectively randomized to have myopic topography-guided LASIK treatment and the contralateral eye to have SMILE; Digital image analysis of the achieved centration to the aimed corneal vertex was assessed for both procedures on the perioperative Scheimpflug tangential curvature maps, using a proprietary digitized methodology. RESULTS The radial displacement between the attempted centration on the corneal vertex versus the center of the effective anterior corneal curvature flattening was on average 130 ± 62 μm in the LASIK group and 313 ± 144μm in the SMILE group (P<0.001). CONCLUSIONS In this contralateral eye study, topography-guided myopic LASIK was found to achieve significantly better effective centration compared to myopic SMILE, in regards digitally measured decentration of the effective refractive change achieved in the anterior corneal curvature from the corneal vertex. This may explain the previously reported superior visual outcomes in the LASIK group eyes when compared to the contralateral SMILE group eyes.
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Santodomingo‐rubido J, Villa‐collar C, Gilmartin B, Gutiérrez‐ortega R, Suzaki A. The effects of entrance pupil centration and coma aberrations on myopic progression following orthokeratology. Clin Exp Optom 2021; 98:534-40. [DOI: 10.1111/cxo.12297] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 02/17/2015] [Accepted: 02/23/2015] [Indexed: 01/04/2023] Open
Affiliation(s)
| | | | - Bernard Gilmartin
- School of Life and Health Sciences, Aston University, Birmingham, UK,
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Wu F, Yang Y, Dougherty PJ. Contralateral comparison of wavefront‐guided LASIK surgery with iris recognition versus without iris recognition using the MEL80 Excimer laser system. Clin Exp Optom 2021; 92:320-7. [PMID: 19302674 DOI: 10.1111/j.1444-0938.2009.00362.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Fang Wu
- Department of Ophthalmology, the Second Hospital Affiliated to Zhejiang University, Hangzhou, China
| | - Yabo Yang
- Department of Ophthalmology, the Second Hospital Affiliated to Zhejiang University, Hangzhou, China
| | - Paul J Dougherty
- Dougherty Laser Vision Institute, Camarillo, California, USA
- Ophthalmology, Jules Stein Eye Institute at UCLA, Los Angeles, California, USA
E‐mail:
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Akondi V, Dubra A. Average gradient of Zernike polynomials over polygons. OPTICS EXPRESS 2020; 28:18876-18886. [PMID: 32672177 PMCID: PMC7340383 DOI: 10.1364/oe.393223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/03/2020] [Accepted: 05/25/2020] [Indexed: 05/23/2023]
Abstract
Wavefront estimation from slope sensor data is often achieved by fitting measured slopes with Zernike polynomial derivatives averaged over the sampling subapertures. Here we discuss how the calculation of these average derivatives can be reduced to one-dimensional integrals of the Zernike polynomials, rather than their derivatives, along the perimeter of each subaperture. We then use this result to derive closed-form expressions for the average Zernike polynomial derivatives over polygonal areas, only requiring evaluation of polynomials at the polygon vertices. Finally, these expressions are applied to simulated Shack-Hartmann wavefront sensors with 7 and 23 fully illuminated lenslets across a circular pupil, with their accuracy and calculation time compared against commonly used integration methods.
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Ozulken K, Yuksel E, Uzel MM. Effect of topical pilocarpine on refractive surgery outcomes. Int Ophthalmol 2019; 40:733-740. [PMID: 31758508 DOI: 10.1007/s10792-019-01235-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/16/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE To investigate the effect of topical pilocarpine on topical cycloplegia and on the results of refractive surgery. METHODS The study included 100 eyes of 100 patients who underwent laser-assisted in situ keratomileusis. Group 1 comprised patients who wanted to undergo surgery on the same day after cycloplegic examination and were applied with 2% pilocarpine hydrochloride; group 2 comprised patients whose pupils spontaneously went into the natural position. Corneal thickness, mean refractive spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), pupil diameter, pupil center shift and high-order aberrations (HOAs) were compared between the two groups. RESULTS There were no statistically significant differences between the groups in respect of preoperative age, gender, corneal thickness, MRSE, UDVA and CDVA. The pupil diameter was not statistically significant between the groups. Pupil diameter after pilocarpine was not statistically significant when compared with the natural pupil diameter. There were no statistically significant differences in postoperative HOA between the two groups. CONCLUSIONS The pupillary dilatation and the associated pupillary shift were reduced with pilocarpine. Postoperative refractive values and aberrations showed no difference between the groups.
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Affiliation(s)
- Kemal Ozulken
- Ophthalmology Department, TOBB ETU Medical School Hospital, Yasam Cad. No:5 Sogutozu, Ankara, Turkey.
| | - Erdem Yuksel
- Ophthalmology Department, Kastamonu University, Kastamonu, Turkey
| | - Mehmet Murat Uzel
- Ophthalmology Department, Afyonkarahisar State Hospital, Afyonkarahisar, Turkey
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Decentration measurements using Placido corneal tangential curvature topography and Scheimpflug tomography pachymetry difference maps after small-incision lenticule extraction. J Cataract Refract Surg 2019; 45:1067-1073. [PMID: 31133417 DOI: 10.1016/j.jcrs.2019.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/30/2019] [Accepted: 03/15/2019] [Indexed: 11/23/2022]
Abstract
PURPOSE To assess the agreement of decentration measurements between tangential curvature topography and tomography pachymetry difference maps after a small-incision lenticule extraction (SMILE) procedure. SETTING Yonsei University College of Medicine and Eyereum Eye Clinic, Seoul, South Korea. DESIGN Retrospective case series. METHODS Decentrations and pupillary offset (angle κ) were analyzed and compared using two different methods. A difference map of the tangential curvature was generated with a Placido corneal topographer (Keratron Scout) and a pachymetry difference map was generated with a Scheimpflug tomographer (Pentacam) for each eye, using preoperative and 3-month postoperative scans. Decentrations were also compared using a vector difference plot for the two maps. RESULTS The study comprised 155 eyes (155 patients). The magnitude of decentration was 0.27 mm ± 0.17 (SD) (range 0.02 to 0.88 mm) with the tangential curvature difference maps and 0.26 ± 0.20 mm (range 0.00 to 0.91 mm) with the pachymetry difference maps, showing no significant difference in the arithmetic values of decentration (P = .124). However, the vector difference in pupillary offset between preoperative and postoperative measurements from the pachymetry difference map significantly correlated with the magnitude of vector differences of decentration between the two maps (P = .007). The vector difference plot also showed a wide distribution spread to all 4 quadrants, demonstrating a lack of agreement. CONCLUSIONS Although there was no significant difference between the scalar magnitude of decentration with the tangential topography difference maps and tomography pachymetry difference maps, the vector differences did not agree and increasing error was present with increasing differences in pupillary offset in the pachymetry difference maps.
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Lee H, Roberts CJ, Arba-Mosquera S, Kang DSY, Reinstein DZ, Kim TI. Relationship Between Decentration and Induced Corneal Higher-Order Aberrations Following Small-Incision Lenticule Extraction Procedure. Invest Ophthalmol Vis Sci 2019; 59:2316-2324. [PMID: 29847636 DOI: 10.1167/iovs.17-23451] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the amount of lenticule decentration following small-incision lenticule extraction (SMILE) by using the Keratron Scout tangential topography difference map, and the relationship between the magnitudes of total decentration and induced corneal higher-order aberrations (HOAs). Methods This retrospective observational case series study analyzed decentration values obtained from the Keratron Scout tangential topography difference map of 360 eyes (360 patients) that underwent SMILE. Root mean square total HOAs, third order coma aberration, fourth order spherical aberration, as well as individual coefficients for vertical and horizontal coma were measured preoperatively and 3-months postoperatively. Simple linear regression analysis and piecewise regression models were used to determine the relationship between the magnitudes of total decentration and induced corneal HOAs. Results The mean total decentration distance from the corneal vertex was 0.36 ± 0.22 mm (range, 0.02-1.27 mm). There were significant differences in total HOAs, coma, vertical and horizontal comas, and spherical aberration between preoperative and 3-month postoperative assessments. Significant relationships between the magnitudes of total decentration and induced corneal HOAs were noted. Subgroup analysis according to the degree of total decentration (group I, total decentered displacement ≤0.335 mm; and group II, total decentered displacement >0.335 mm) revealed that induced changes in total HOAs, coma, vertical coma, and spherical aberration were significantly larger in group II than in group I. Conclusions A minimal degree of decentration was closely related to a smaller induction of corneal HOAs. Efforts to optimize centration are critical for achieving better surgical outcomes in SMILE.
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Affiliation(s)
- Hun Lee
- Department of Ophthalmology, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, South Korea.,The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
| | - Cynthia J Roberts
- Department of Ophthalmology & Visual Science and Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States
| | | | | | - Dan Z Reinstein
- London Vision Clinic, London, United Kingdom.,Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States.,Centre Hospitalier National d'Ophtalmologie, Paris, France
| | - Tae-Im Kim
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
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Kim WK, Ryu IH, Kim JS, Jeon GH, Lee IS, Kim HS, Kim JK. Clinical Outcomes of One Day Small-incision Lenticule Extraction Compared with Scheduled Methods for Myopic Patients. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2019. [DOI: 10.3341/jkos.2019.60.3.223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Chan TCY, Wan KH, Kang DSY, Tso THK, Cheng GPM, Wang Y. Effect of corneal curvature on optical zone decentration and its impact on astigmatism and higher-order aberrations in SMILE and LASIK. Graefes Arch Clin Exp Ophthalmol 2018; 257:233-240. [DOI: 10.1007/s00417-018-4165-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/29/2018] [Accepted: 10/15/2018] [Indexed: 10/28/2022] Open
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Kang DSY, Lee H, Reinstein DZ, Roberts CJ, Arba-Mosquera S, Archer TJ, Kim EK, Seo KY, Kim TI. Comparison of the Distribution of Lenticule Decentration Following SMILE by Subjective Patient Fixation or Triple Marking Centration. J Refract Surg 2018; 34:446-452. [DOI: 10.3928/1081597x-20180517-02] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/07/2018] [Indexed: 11/20/2022]
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Kaya A, Keçeli AS, Can AB, Çakmak HB. Cyclotorsion measurement using scleral blood vessels. Comput Biol Med 2017; 87:152-161. [PMID: 28595130 DOI: 10.1016/j.compbiomed.2017.05.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/29/2017] [Accepted: 05/29/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND OBJECTIVES Measurements of the cyclotorsional movement of the eye are crucial in refractive surgery procedures. The planned surgery pattern may vary substantially during an operation because of the position and eye movements of the patient. Since these factors affect the outcome of an operation, eye registration methods are applied in order to compensate for errors. While the majority of applications are based on features of the iris, we propose a registration method which uses scleral blood vessels. Unlike previous offline techniques, the proposed method is applicable during surgery. METHODS The sensitivity of the proposed registration method is tested on an artificial benchmark dataset involving five eye models and 46,305 instances of eye images. The cyclotorsion angles of the dataset vary between -10° and +10° at 1° intervals. Repeated measurements and ANOVA and Cochran's Q tests are applied in order to determine the significance of the proposed method. Additionally, a pilot study is carried out using data obtained from a commercially available device. The real data are validated using manual marking by an expert. RESULTS AND CONCLUSIONS The results confirm that the proposed method produces a smaller error rate (mean = 0.44 ± 0.41) compared to the existing method in [1] (mean = 0.64 ± 0.58). A further conclusion is that feature extraction algorithms affect the results of the proposed method. The SIFT (mean = 0.74 ± 0.78), SURF64 (mean = 0.56 ± 0.46), SURF128 (mean = 0.57 ± 0.48) and ASIFT (mean = 0.29 ± 0.25) feature extraction algorithms were examined; the ASIFT method was the most successful of these algorithms. Scleral blood vessels are observed to be useful as a feature extraction region due to their textural properties.
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Affiliation(s)
- Aydın Kaya
- Hacettepe University, Faculty of Engineering, Department of Computer Engineering, 06800, Ankara, Turkey.
| | - Ali Seydi Keçeli
- Hacettepe University, Faculty of Engineering, Department of Computer Engineering, 06800, Ankara, Turkey.
| | - Ahmet Burak Can
- Hacettepe University, Faculty of Engineering, Department of Computer Engineering, 06800, Ankara, Turkey.
| | - Hasan Basri Çakmak
- Hitit University, Faculty of Medicine, Department of Ophthalmology, 19030, Çorum, Turkey.
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Zhang J, Zhang SS, Yu Q, Lian JC. Comparison of visual effects of FS-LASIK for myopia centered on the coaxially sighted corneal light reflex or the line of sight. Int J Ophthalmol 2017; 10:624-631. [PMID: 28503438 DOI: 10.18240/ijo.2017.04.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/01/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To compare visual quality after femtosecond laser in situ keratomileusis (FS-LASIK), between the coaxially sighted corneal light reflex (CSCLR) group and conventional ablation line of sight (LOS) group. METHODS In total, 243 eyes (122 patients) were treated with centration on the CSCLR (visual axis) and 238 eyes (119 patients) treated with centration on the pupil center (LOS). Postoperative outcomes [uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA)], safety index, efficacy index, refractive outcome, ablation center distance from the visual axis, corneal high-order aberrations, subjective discomfort glare and shadowing incidence rate, and contrast sensitivity at 1, 3, and 6mo were measured and compared. RESULTS The mean age was 27.77±7.1y in the CSCLR group and 26.03±7.70y in the LOS group. Preoperatively, the manifest refraction spherical equivalent (MRSE) was -6.68±2.60 D in the CSCLR group and -6.65±2.68 D in the LOS group. The postoperative UCVA, BSCVA, MRSE (-0.03±0.263 D in the CSCLR group, -0.05±0.265 D in the LOS group), efficacy index (1.04, 1.03), and safety index (1.09, 1.08) were not significantly different between the groups (all P>0.05). In total, 3% lost one line and more of BSCVA in the CSCLR group, as 9% in the LOS group postoperatively (P<0.05). The ablation center deviation was 0.20±0.15 mm from the visual axis (Pentacam system default setting; range, 0-0.75 mm) in the CSCLR group, and 0.43±0.22 mm (range, 0-1.32 mm) in the LOS group (P<0.0001). Statistically significant greater augmentation of total corneal higher-order aberrations (0.15±0.10 µm and 0.20±0.12 µm respectively, P=0.03) and vertical and horizontal coma (P<0.0001) were noted in the LOS group. Subjective discomfort glare and shadowing incidence rates were 8.59% and 17.5% in the CSCLR and LOS groups, respectively (P<0.05). The 1-month postoperative contrast sensitivity visual acuity in the CSCLR group was significantly higher than that in the LOS group on contrast (100%, 25%, 10%) with a dark background, but there was no significant difference between the groups at 3 or 6m. CONCLUSION Myopic LASIK centered on the CSCLR achieves significantly lower induction of loss of BSCVA, corneal high-order aberrations, and lower risk of subjective discomfort glare and shadowing, and lower decline in early contrast sensitivity by comparison with centration on the LOS, giving advantages in visual quality postoperatively.
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Affiliation(s)
- Jing Zhang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, China
| | | | - Qin Yu
- New Vision Eye Clinic, Shanghai 200011, China
| | - Jing-Cai Lian
- Shanghai Xinshijie Zhongxing Eye Hospital, School of Medicine, Shanghai Tongji University, Shanghai 200070, China
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Chang JS, Law AK, Ng JC, Chan VK. Comparison of refractive and visual outcomes with centration points 80% and 100% from pupil center toward the coaxially sighted corneal light reflex. J Cataract Refract Surg 2016; 42:412-9. [DOI: 10.1016/j.jcrs.2015.09.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/21/2015] [Accepted: 09/23/2015] [Indexed: 11/29/2022]
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Effect of Flat Cornea on Visual Outcome after LASIK. J Ophthalmol 2015; 2015:794854. [PMID: 26693347 PMCID: PMC4677010 DOI: 10.1155/2015/794854] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 11/08/2015] [Accepted: 11/10/2015] [Indexed: 11/17/2022] Open
Abstract
Purpose. To evaluate the effect of preoperative and postoperative keratometry on the refractive outcome after laser in situ keratomileusis (LASIK) for moderate and high myopia. Methods. Records of 812 eyes (420 patients) with myopia ≥−6 D who had LASIK at Sohag Laser Center, Egypt, from January 2010 to November 2013, were retrospectively analyzed. Main outcome measures were postoperative corrected distance visual acuity (CDVA), postoperative spherical equivalence, and postoperative Q factor. Results. LASIK was performed in 812 eyes (mean age 21.8 ± 5.2 years). Patients were grouped according to the degree of preoperative myopia into three groups: Group 1, −6 D to −7.9 D; Group 2, −8 to −9.9 D; and Group 3, −10 to −12 D. The refractive outcome among the different myopia groups was stratified by pre- and postoperative keratometry. A trend toward greater undercorrection was noted in eyes with preoperative keratometry <43.5 D compared with those with steeper keratometry >46 D in all myopia groups. The undercorrection was also noted in postoperative keratometry groups <35 D. Conclusions. Preoperative and postoperative keratometry appeared to influence the refractive outcome especially in high myopic eyes.
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Wavefront-Guided Photorefractive Keratectomy with the Use of a New Hartmann-Shack Aberrometer in Patients with Myopia and Compound Myopic Astigmatism. J Ophthalmol 2015; 2015:514837. [PMID: 26504595 PMCID: PMC4609463 DOI: 10.1155/2015/514837] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/12/2015] [Accepted: 07/21/2015] [Indexed: 11/25/2022] Open
Abstract
Purpose. To assess refractive and visual outcomes and patient satisfaction of wavefront-guided photorefractive keratectomy (PRK) in eyes with myopia and compound myopic astigmatism, with the ablation profile derived from a new Hartmann-Shack aberrometer. Methods. In this retrospective study, 662 eyes that underwent wavefront-guided PRK with a treatment profile derived from a new generation Hartmann-Shack aberrometer (iDesign aberrometer, Abbott Medical Optics, Inc., Santa Ana, CA) were analyzed. The preoperative manifest sphere ranged from −0.25 to −10.75 D, and preoperative manifest cylinder was between 0.00 and −5.25 D. Refractive and visual outcomes, vector analysis of the change in refractive cylinder, and patient satisfaction were evaluated. Results. At 3 months, 91.1% of eyes had manifest spherical equivalent within 0.50 D. The percentage of eyes achieving uncorrected distance visual acuity 20/20 or better was 89.4% monocularly and 96.5% binocularly. The mean correction ratio of refractive cylinder was 1.02 ± 0.43, and the mean error of angle was 0.00 ± 14.86° at 3 months postoperatively. Self-reported scores for optical side effects, such as starburst, glare, halo, ghosting, and double vision, were low. Conclusion. The use of a new Hartmann-Shack aberrometer for wavefront-guided photorefractive keratectomy resulted in high predictability, efficacy, and patient satisfaction.
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Reinstein DZ, Gobbe M, Gobbe L, Archer TJ, Carp GI. Optical Zone Centration Accuracy Using Corneal Fixation-based SMILE Compared to Eye Tracker-based Femtosecond Laser-assisted LASIK for Myopia. J Refract Surg 2015; 31:586-92. [DOI: 10.3928/1081597x-20150820-03] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/13/2015] [Indexed: 11/20/2022]
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25
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Mosquera SA, Verma S. Effects of torsional movements in refractive procedures. J Cataract Refract Surg 2015; 41:1752-66. [DOI: 10.1016/j.jcrs.2015.07.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 11/26/2022]
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Smadja D, Santhiago MR, Tellouck J, De Castro T, Lecomte F, Mello GR, Touboul D. Safety and efficacy of wavefront-guided myopic laser in situ keratomileusis using a new wavefront sensor technology: First 100 cases. J Cataract Refract Surg 2015; 41:1588-93. [DOI: 10.1016/j.jcrs.2014.11.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/19/2014] [Accepted: 11/26/2014] [Indexed: 11/17/2022]
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Schallhorn SC, Venter JA, Hannan SJ, Hettinger KA. Clinical outcomes of wavefront-guided laser in situ keratomileusis to treat moderate-to-high astigmatism. Clin Ophthalmol 2015. [PMID: 26203219 PMCID: PMC4508064 DOI: 10.2147/opth.s87887] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the refractive and visual outcomes of wavefront-guided laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism and cylindrical component ≥2.0 diopter (D). METHODS In this retrospective study, 611 eyes that underwent LASIK for simple or compound myopic astigmatism were analyzed. Preoperative refractive cylinder ranged from -2.00 D to -6.00 D (mean -2.76±0.81 D), and the sphere was between 0.00 D and -9.75 D (mean -2.79±2.32 D). Predictability, visual outcomes, and vector analysis of changes in refractive astigmatism were evaluated. RESULTS At 3 months after LASIK, 83.8% of eyes had uncorrected distance visual acuity of 20/20 or better, 90.3% had manifest spherical equivalent within ±0.50 D, and 79.1% had residual refractive cylinder within ±0.50 D of intended correction. The mean correction ratio for refractive cylinder was 0.92±0.14, the mean error of angle was -0.45°±2.99°, and the mean error vector was 0.37±0.38 D. A statistically significant correlation was found between the error of magnitude (arithmetic difference in the magnitudes between surgically induced refractive correction and intended refractive correction) and the intended refractive correction (r=0.26, P<0.01). CONCLUSION Wavefront-guided LASIK for the correction of myopic astigmatism is safe, effective, and predictable.
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Affiliation(s)
- Steven C Schallhorn
- University of California, San Francisco, CA, USA ; Optical Express, Glasgow, UK
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Shaheen MS, El-Kateb M, Hafez TA, Piñero DP, Khalifa MA. Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study. J Refract Surg 2015; 31:411-8. [DOI: 10.3928/1081597x-20150521-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 04/09/2015] [Indexed: 11/20/2022]
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Arba Mosquera S, Verma S, McAlinden C. Centration axis in refractive surgery. EYE AND VISION 2015; 2:4. [PMID: 26605360 PMCID: PMC4655455 DOI: 10.1186/s40662-015-0014-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/10/2015] [Indexed: 11/10/2022]
Abstract
The human eye is an asymmetric optical system and the real cornea is not a rotationally symmetrical volume. Each optical element in the eye has its own optical and neural axes. Defining the optimum center for laser ablation is difficult with many available approaches. We explain the various centration approaches (based on these reference axes) in refractive surgery and review their clinical outcomes. The line-of-sight (LOS) (the line joining the entrance pupil center with the fixation point) is often the recommended reference axis for representing wavefront aberrations of the whole eye (derived from the definition of chief ray in geometrical optics); however pupil centration can be unstable and change with the pupil size. The corneal vertex (CV) represents a stable preferable morphologic reference which is the best approximate for alignment to the visual axis. However, the corneal light reflex can be considered as non-constant, but dependent on the direction of gaze of the eye with respect to the light source. A compromise between the pupil and CV centered ablations is seen in the form of an asymmetric offset where the manifest refraction is referenced to the CV while the higher order aberrations are referenced to the pupil center. There is a need for a flexible choice of centration in excimer laser systems to design customized and non-customized treatments optimally.
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Affiliation(s)
- Samuel Arba Mosquera
- SCHWIND eye-tech-solutions, Kleinostheim, Germany ; Recognized Research Group in Optical Diagnostic Techniques, University of Valladolid, Valladolid, Spain ; Department of Ophthalmology and Sciences of Vision, University of Oviedo, Oviedo, Spain
| | | | - Colm McAlinden
- Flinders University, Adelaide, South Australia Australia ; Wenzhou Medical University, Wenzhou, Zhejiang China
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Abstract
BACKGROUND Pupil centroid shift (PCS) is an easily measured parameter which is rarely taken into consideration when planning surgery. PURPOSE The aim of this study was to determine the physiological range of PCS and to evaluate its role in refractive and cataract surgery. METHODS The pupil center was measured in 103 eyes of 103 patients using the newest PCS module of the Allegro Topolyzer Vario (Version 1.76r58, Wavelight-Alcon, Erlangen, Germany) and the difference between a mesopic and a photopic environment was determined as PCSm. Additionally, these measurements were linearly extrapolated to pupil diameters of 2 mm and 7 mm (photopic-scotopic, PCSe). The statistical analysis included correlations between various demographic and topographic parameters and PCS. RESULTS The average (± standard deviation) PCSm was 0.12 ± 0.08 mm with a range of 0.02-0.53 mm, with 2 eyes out of 95 (2%) having a PCSm of more than 0.4 mm. The extrapolated PCSe was 0.24 ± 0.16 mm and ranged from 0.03 to 0.78 mm, with 14 eyes out of 95 (15%) having a PCSe of more than 0.4 mm. Of the 95 eyes 3 (3%) showed a PCSe of more than 0.7 mm. There was no correlation between PCS with any of the demographic parameters tested. CONCLUSION Up to 15% of the patients showed a PCS of more than 0.4 mm which requires a decision of the (refractive) ophthalmic surgeon as to whether the optical zone should be centered on the photopic or mesopic/scotopic pupil center. In the 3% of patients with a PCSe value greater than 0.7 mm, the implantation of multifocal intraocular lens (IOL) is not recommended.
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Smadja D, De Castro T, Tellouck L, Tellouck J, Lecomte F, Touboul D, Paya C, Santhiago MR. Wavefront Analysis After Wavefront-Guided Myopic LASIK Using a New Generation Aberrometer. J Refract Surg 2014; 30:610-5. [DOI: 10.3928/1081597x-20140815-01] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Schallhorn S, Brown M, Venter J, Teenan D, Hettinger K, Yamamoto H. Early clinical outcomes of wavefront-guided myopic LASIK treatments using a new-generation hartmann-shack aberrometer. J Refract Surg 2013; 30:14-21. [PMID: 24202703 DOI: 10.3928/1081597x-20131029-02] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/05/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To provide an initial retrospective evaluation of early postoperative outcomes after wavefront-guided myopic LASIK using a new-generation Hartmann-Shack wavefront sensor. METHODS A noncomparative, retrospective study of 243 eyes of 126 patients that underwent primary wavefront-guided LASIK, using wavefront data obtained with a new Hartmann-Shack aberrometer (iDesign Advanced WaveScan aberrometer; Abbott Medical Optics, Inc., Santa Ana, CA). Visual acuity, refraction, and patient satisfaction were evaluated 1 month after surgery. RESULTS The manifest spherical equivalent was reduced from -3.28 ± 1.79 diopters (D) (range: -9.88 to -0.38 D) before surgery to -0.03 ± 0.29 D (range: -1.00 to +1.25 D) 1 month after surgery. The manifest spherical equivalent was within 0.50 and 1.00 D of target in 93.0% and 99.6% of eyes, respectively. Manifest astigmatism preoperatively (-0.72 ± 0.67 [range: 0.0 to -5.00 D]) was reduced to -0.14 ± 0.20 (range: 0.0 to -1.00 D) at 1 month and the vector-derived correction ratio (surgically induced refractive change/intended refractive correction) was 1.02 ± 0.30. Uncorrected distance visual acuity of 20/16, 20/20, and 20/25 or better was achieved in 79.0%, 93.4%, and 96.7% of eyes, respectively. No eyes lost two or more lines of corrected distance visual acuity, whereas a gain of one or more lines was observed in 14.0%. Most patients (98.5%) reported that they were satisfied with the outcome of their procedure. CONCLUSIONS Wavefront-guided LASIK using the new aberrometer in this retrospective evaluation was effective, safe, and predictable in the early postoperative time period for the correction of myopia with high patient satisfaction.
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Shaheen MS, Massoud TH, Ezzeldin H, Khalifa MA. Four-year visual, refractive, and contrast sensitivity outcomes after wavefront-guided myopic LASIK using an advanced excimer laser platform. J Refract Surg 2013; 29:816-22. [PMID: 24168789 DOI: 10.3928/1081597x-20131023-04] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 08/05/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the 4-year visual, refractive, and contrast sensitivity outcomes of wavefront-guided LASIK for the correction of low to moderate myopia using the VISX CustomVue technology (Abbott Medical Optics, Inc., Santa Ana, CA). METHODS This was a prospective study including 255 consecutive eyes of 145 patients (age range: 19 to 55 years) with low to moderate myopia (mean spherical equivalent: -3.36 ± 1.71 diopters [D]) undergoing laser refractive surgery. Wavefront-guided LASIK was performed in all eyes using the VISX STAR S4 IR excimer laser platform and the CustomVue procedure for the ablation profile design. Visual, refractive, and contrast sensitivity changes were evaluated during a 4-year follow-up period. RESULTS Postoperative logMAR uncorrected distance visual acuity was 0.1 or better (20/25 Snellen) in 98.0% and 100% of eyes at 1 and 4 years, respectively. At 4 years postoperatively, mean spherical equivalent was reduced significantly to a mean value of -0.22 ± 0.28 D (P < .01), with 97.3% of eyes with a spherical equivalent within ±0.50 D. The astigmatic power vector component J0 of manifest refraction was also reduced significantly (P < .01). Postoperative logMAR corrected distance visual acuity was 0.0 or better (20/20 Snellen) in 96.1% and 98.8% of eyes at 1 and 4 years, respectively. Improvement in contrast sensitivity was observed in some spatial frequencies between 1 and 4 years postoperatively. No significant correlations were found between 4-year contrast sensitivity and corrected distance visual acuity (0.024 ≤ r ≤ -0.120, P ≥ .06). CONCLUSION Wavefront-guided LASIK using the VISX CustomVue technology provides an effective and predictable correction of low to moderate myopia in the long term, preserving the patient's visual acuity and quality.
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Reinstein DZ, Gobbe M, Archer TJ. Coaxially sighted corneal light reflex versus entrance pupil center centration of moderate to high hyperopic corneal ablations in eyes with small and large angle kappa. J Refract Surg 2013; 29:518-25. [PMID: 23909778 DOI: 10.3928/1081597x-20130719-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 04/01/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine whether centering ablations on the coaxially sighted corneal light reflex (CSCLR) in eyes with large angle kappa leads to poor visual outcomes when compared to patients with eyes with negligible angle kappa that by default would be centered on the entrance pupil. In eyes with no angle kappa, the CSCLR coincides with the entrance pupil center, whereas eyes with large angle kappa possess an offset between the CSCLR and the entrance pupil center. METHODS This study was a retrospective case series of consecutive patients treated by hyperopic LASIK using the MEL80 excimer laser (Carl Zeiss Meditec, Jena, Germany). All ablations were centered on the CSCLR using the standard non-wavefront-guided ablation profile. Angle kappa was classified according to pupil offset defined as the distance in the corneal plane between the entrance pupil center and the corneal vertex. Eyes were divided into two discrete groups according to the pupil offset: small angle kappa for pupil offset of 0.25 mm or less (n = 30) and large angle kappa for pupil offset of 0.55 mm or greater (n = 30). Safety, accuracy, cylinder vector analysis, contrast sensitivity, vertex centered corneal aberrations, entrance pupil centered whole eye aberrometry, and night vision disturbances were compared between the two groups. RESULTS There were no statistically significant differences in safety, accuracy, induced astigmatism, contrast sensitivity, or night vision disturbances between the two groups. There was also no statistically significant difference between groups for vertex centered corneal aberrations; however, as expected, coma was higher in the large angle kappa group for entrance pupil centered aberrometry because the treatment had been centered on the CSCLR rather than the entrance pupil center. CONCLUSION Refractive outcomes of high hyperopic LASIK were not found to be worse for eyes where ablation was centered more than 0.55 mm from the entrance pupil as determined by CSCLR in eyes with large angle kappa. The absence of poor quality visual outcomes in cases, which by entrance pupil centration are considered significantly "decentered," supports the notion that centration relative to the CSCLR may be preferable. This provides evidence that refractive corneal ablation should not be systematically aligned with the entrance pupil center.
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Mello GR, Rocha KM, Santhiago MR, Smadja D, Krueger RR. Applications of wavefront technology. J Cataract Refract Surg 2012; 38:1671-83. [DOI: 10.1016/j.jcrs.2012.07.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 01/27/2012] [Accepted: 02/13/2012] [Indexed: 10/28/2022]
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Taneri S, Oehler S, MacRae SM. Aspheric wavefront-guided versus wavefront-guided LASIK for myopic astigmatism with the Technolas 217z100 excimer laser. Graefes Arch Clin Exp Ophthalmol 2012; 251:609-16. [PMID: 22926254 DOI: 10.1007/s00417-012-2143-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/07/2012] [Accepted: 08/11/2012] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare clinical outcomes of wavefront-guided LASIK with and without aspheric compensation in myopic eyes. METHODS In this observational, single-center study, 134 eyes were treated using an aspheric module in combination with wavefront-guided profiles (PTA-algorithm) and compared to 146 eyes treated with the predecessor wavefront-guided software (APT) that has no aspheric compensation. All treatment plans included the Rochester nomogram that accounts for the preoperative manifest refraction and interaction of higher order aberrations. Active eye-tracking (including cyclorotational movements) was utilized during photoablation. RESULTS Results at the 3-month follow-up: 67 % of PTA-treated eyes and 39 % of APT-treated eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better. Change in mean higher order aberration root-mean-square (HOA RMS) after PTA treatments was not statistically significant (p = 0.18). The increase in HOA RMS after APT treatments was statistically significant (p = 0.003). Change in mean postop spherical aberration (SA) after PTA treatments was not statistically significant (p = 0.27). The change in SA after APT treatments was statistically significant (p = 0.001). In both cohorts, mean uncorrected low-contrast visual acuity was statistically not different to preoperative corrected values. CONCLUSIONS Adding an aspheric compensation to wavefront-guided myopic LASIK statistically improved clinical results in terms of visual acuity and refractive outcomes. Low-contrast visual acuity was not negatively affected in either group. While in APT-treated eyes mean HOA RMS and mean SA were significantly increased postoperatively, PTA-treated eyes showed neither induced HOA RMS nor induced SA.
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Affiliation(s)
- Suphi Taneri
- Eye Department St Francis Hospital, Center for Refractive Surgery, Muenster, Germany.
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Arba Mosquera S, Ewering T. New Asymmetric Centration Strategy Combining Pupil and Corneal Vertex Information for Ablation Procedures in Refractive Surgery: Theoretical Background. J Refract Surg 2012; 28:567-73. [DOI: 10.3928/1081597x-20120703-01] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 03/27/2012] [Indexed: 11/20/2022]
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Smadja D, Reggiani-Mello G, Santhiago MR, Krueger RR. Wavefront ablation profiles in refractive surgery: description, results, and limitations. J Refract Surg 2012; 28:224-32. [PMID: 22373035 DOI: 10.3928/1081597x-20120217-01] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Accepted: 12/06/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To provide an overview of the clinical results of different ablation profiles based on wavefront technology and discuss their characteristics and limitations. METHODS Literature review of studies reporting results of ablation profiles based on wavefront technology in virgin healthy eyes. RESULTS Over the past 10 years, a large number of studies comparing different treatment algorithms and newer excimer laser platforms have been published. Thirty-six clinical studies including 3637 eyes analyzing the clinical results obtained after wavefront-guided, wavefront-optimized, and Q-factor profiles have been reviewed. Although wavefront-driven profiles allowed reduction of the amount of induced optical aberrations with conventional ablations, thereby improving the quality of vision, it appears that no algorithm of treatment or excimer laser platform has demonstrated a clear superiority over another. Wound healing and unexpected biomechanical response to surgery affect the accuracy of customized treatments and produce variable results. In addition, it is difficult to rigorously analyze and compare findings among different studies because of the diverse variety in which the data are reported. CONCLUSIONS Despite several technological improvements over the years, wavefront ablation profiles have not consistently demonstrated superiority in terms of visual acuity and lower order aberrations compared to the standard procedure, although the induction of higher order aberrations has been reduced. The concept of an individualized eye model has emerged recently, based on the optical ray tracing algorithm, and could theoretically provide a higher level of customization, thus fulfilling the promise of "super vision."
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Affiliation(s)
- David Smadja
- Refractive Surgery Department, Cole Eye Institute, Cleveland Clinic Foundation, Ohio, USA.
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Smadja D, Reggiani-Mello G, Touboul D, Colin J. Les profils de photoablation cornéenne en chirurgie réfractive. Partie 1 : la quête de l’excellence. J Fr Ophtalmol 2012; 35:126-35. [DOI: 10.1016/j.jfo.2011.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 08/30/2011] [Accepted: 09/02/2011] [Indexed: 10/14/2022]
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Three-month clinical outcomes with static and dynamic cyclotorsion correction using the SCHWIND AMARIS. Cornea 2011; 30:951-7. [PMID: 21694596 DOI: 10.1097/ico.0b013e318207eac2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate intraoperative static and dynamic cyclotorsions and postoperative outcomes on astigmatism and high-order aberration in astigmatic or aberrated eyes that underwent laser in situ keratomileusis treatments with advanced cyclotorsion control using the SCHWIND AMARIS. METHODS Fifty eyes (30 for aberration neutral and 20 for corneal wavefront) were treated. Treatments were planned with Custom Ablation Manager and ablations were performed using the SCHWIND AMARIS. Laser in situ keratomileusis flaps were cut with an LDV femtosecond laser. Cyclotorsional movements were evaluated for static cyclotorsion component (SCC) for mean and repeatability, and for dynamic cyclotorsion component (DCC) for mean and amplitude. Clinical outcomes were evaluated for predictability, refractive outcome, safety, and wavefront aberration. RESULTS Registration rates were 90% for SCC and 98% for DCC. SCC was within ± 5 degrees in 64% of cases. Repeatability of SCC was ± 1 degree in 88% of cases. Mean DCC was within ± 1 degree in 98% of cases, partly compensating for SCC. DCC amplitude was within ± 2 degrees in 84% of cases. At 3-month follow-up, 88% of eyes were within ± 0.50 diopter (D) of astigmatism. Mean defocus was -0.06 ± 0.24 D and astigmatism was 0.27 ± 0.20 D. Best spectacle-corrected visual acuity improved in 42% of eyes versus 2% losing 1 line. In corneal wavefront-customized treatments, coma, trefoil, spherical aberration, and root mean square high-order magnitudes at 6-mm analysis diameter were reduced by -0.04, -0.13, -0.04, and -0.10 μm, respectively. CONCLUSIONS Laser in situ keratomileusis with advanced cyclotorsion compensation using the SCHWIND AMARIS is safe and predictable and yields superior visual outcomes. Refractions and high-order aberrations were reduced to subclinical values without applying additional nomograms, showing the excellent performance of the system.
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Fares U, Suleman H, Al-Aqaba MA, Otri AM, Said DG, Dua HS. Efficacy, predictability, and safety of wavefront-guided refractive laser treatment: metaanalysis. J Cataract Refract Surg 2011; 37:1465-75. [PMID: 21782089 DOI: 10.1016/j.jcrs.2011.02.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 02/23/2011] [Accepted: 02/26/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE To compare the efficacy, predictability, safety, and induced higher-order aberrations (HOAs) between wavefront-guided and non-wavefront-guided ablations. SETTING Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, United Kingdom. DESIGN Metaanalysis. METHODS The Cochrane Central Register of Controlled Trials, PubMED, and EMBASE were searched for randomized controlled trails. Trials meeting the selection criteria were quality appraised and data extracted by 2 independent authors. Measures of association were pooled quantitatively using metaanalytical methods. Comparison between wavefront-guided and non-wavefront-guided ablations was measured as pooled odds ratios (ORs) or weighted mean differences. The pooled ORs and 95% confidence intervals (CIs) were computed for efficacy, safety, and predictability. The weighted mean difference and 95% CIs were used to compare induced HOAs. RESULTS Eight trials involving 955 eyes were included. After wavefront-guided LASIK, the pooled OR of achieving uncorrected distance visual acuity (UDVA) of 20/20 (efficacy) was 1.10 (95% CI, 0.66-1.83; P=.72), the pooled OR of achieving a result within ± 0.50 diopter of intended target (predictability) was 1.03 (95% CI, 0.60-1.75; P=.92), and the weighted mean difference in induced HOAs was -0.09 (95% CI, -0.17 to -0.01; P=.04). No study reported loss of 2 or more lines of Snellen acuity (safety) with either modality. CONCLUSIONS Metaanalysis showed no clear evidence of a benefit of wavefront-guided over non-wavefront-guided ablations. However, there was a lack of standardized reporting of UDVA better than 20/20, which might mask an advantage in wavefront-guided treatment. With high preexisting HOAs, wavefront-guided has advantages over non-wavefront-guided treatment.
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Affiliation(s)
- Usama Fares
- Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, United Kingdom
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Virasch VV, Stwalley D, Kymes SM, Wexler SA. Outcomes of custom laser in situ keratomileusis: dilated wavescans versus undilated wavescans. J Cataract Refract Surg 2011; 37:1847-51. [PMID: 21840679 DOI: 10.1016/j.jcrs.2011.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 04/05/2011] [Accepted: 04/22/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE To evaluate refractive outcomes of custom laser in situ keratomileusis (LASIK) based on undilated and pharmacologically dilated wavefront aberrometry with the Visx laser system. SETTING Clinical refractive practice, St. Louis, Missouri, USA. DESIGN Comparative case series. METHODS Eyes that had LASIK using dilated wavescans (study group) were evaluated for the reason for use of dilated scans; age; preoperative refractive error; preoperative root mean square (RMS), coma, trefoil, and spherical aberration values; postoperative uncorrected distance visual acuity (UDVA); postoperative refractive error; percentage of iris-registration capture; and enhancement rate. The study group was compared with a control group that had LASIK using undilated wavescans. RESULTS The study group comprised 52 eyes (31 patients) and the control group, 104 eyes (55 patients). At 1 month, the mean postoperative UDVA was 20/21 in the study group and 20/22 in the control group and at 3 months, 20/22 and 20/20, respectively. At 1 month, the mean postoperative spherical equivalent (SE) was +0.07 diopter (D) ± 0.49 (SD) in the study group and +0.14 ± 0.30 D in the control group and at 3 months, -0.01 ± 0.44 D and +0.02 ± 0.23 D, respectively; there was no statistically significant difference between groups at either timepoint. There was no statistically significant difference in preoperative RMS or postoperative coma, trefoil, or spherical aberration between the groups. Although the study group had a slightly higher enhancement rate, the difference was not statistically significant. CONCLUSION Compared with custom LASIK based on undilated wavescans, use of dilated wavescans for custom LASIK resulted in comparable postoperative outcomes. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Vanee V Virasch
- Department of Ophthalmology, Rush University Medical Center, Chicago, Illinois, USA
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Arba Mosquera S, Arbelaez MC. Use of a Six-dimensional Eye-tracker in Corneal Laser Refractive Surgery With the SCHWIND AMARIS TotalTech Laser. J Refract Surg 2011; 27:582-90. [DOI: 10.3928/1081597x-20110120-02] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 01/07/2011] [Indexed: 11/20/2022]
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Arbelaez MC, Vidal C, Arba Mosquera S. Comparison of LASEK and LASIK with Thin and Ultrathin Flaps After Excimer Laser Ablation with the SCHWIND Aspheric Ablation Profile. J Refract Surg 2011; 27:38-48. [DOI: 10.3928/1081597x-20100406-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 02/18/2010] [Indexed: 11/20/2022]
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Six-month clinical outcomes of customized treatments minimized for depth and time in laser corneal refractive surgery. Cornea 2010; 30:876-88. [PMID: 20802317 DOI: 10.1097/ico.0b013e3181d3d2ce] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Evaluating the application of 2 methods for minimizing the ablated tissue upon objective minimization of depth and time of Zernike-based customized ablations. SETTING Muscat Eye Laser Center, Muscat, Sultanate of Oman. METHODS Recently developed algorithms for selection of Zernike terms in customized treatments for refractive surgery were used. Clinical outcomes and tissue-saving attributes were evaluated on 2 groups [minimize depth (MD) and minimize volume (MV); 30 eyes each], plus a control group [corneal wavefront (CW); 30 eyes] with conventional customized approach. Clinical outcomes were evaluated in terms of predictability, safety, and contrast sensitivity and tissue-saving attributes in terms of saved depth and time for each condition (in micrometers, seconds, and percentage) and whether minimized depth or time were less than required for equivalent noncustomized treatments. RESULTS Ninety-three percent of treatments in the CW group, 93% in the MD group, and 100% in the MV group were within 0.50 diopters of spherical equivalent (SEq) postoperatively. Forty percent of treatments in the CW group, 34% in the MD group, and 47% in the MV group gained at least 1 line of best spectacle-corrected visual acuity postoperatively. Tissue-saving attributes showed an average saved depth of 8 μm (1-20 μm) and a saved time of 6 seconds (1-15 seconds) in the MD group and 6 μm (0-20 μm) and 8 seconds (2-26 seconds) in the MV group. Proposed corrections were always less deep and shorter than full wavefront corrections. In 43% of the MD cases, corrections were less deep, and in 40% of the MV cases, corrections were shorter than equivalent aberration-free treatments. CONCLUSION The minimization techniques compared here effectively reduced depth and time needed for ablation (up to a maximum of 50% and by 15% in average) without negatively affecting clinical outcomes postoperatively, yielding results equivalent to those of the full customization group.
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Influence of spherical intraocular lens implantation and conventional laser in situ keratomileusis on peripheral ocular aberrations. J Cataract Refract Surg 2010; 36:1127-34. [DOI: 10.1016/j.jcrs.2010.01.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 01/06/2010] [Accepted: 01/07/2010] [Indexed: 11/17/2022]
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Arines J, Prado P, Bará S. Pupil tracking with a Hartmann-Shack wavefront sensor. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:036022. [PMID: 20615024 DOI: 10.1117/1.3447922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We present the theoretical background and experimental validation of a pupil tracking method based on measurement of the irradiance centroid of Hartmann-Shack aberrometric images. The experimental setup consists of a Hartmann-Shack (HS) sensor forming over the same camera the images of the eye's pupil and the aberrometric image. The calibration is made by comparing the controlled displacements induced to an artificial eye with the displacements estimated from the centroid of the pupil and of the HS focal plane. The pupil image is also used for validation of the method when operating with human eyes. The experimental results after calibration show a root mean square error of 10.45 mum for the artificial eye and 27, 10, and 6 mum rms for human eyes tested using Hartmann-Shack images, with signal-to-noise ratios of 6, 8, and 11, respectively. The performance of the method is similar to conventional commercial eye trackers. It avoids the need for using separate tracking devices and their associated synchronization problems. This technique can also be used to reprocess present and stored sets of Hartmann-Shack aberrometric images to estimate the ocular movements that occurred during the measurement runs, and, if convenient, to correct the measured aberrations from their influence.
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Affiliation(s)
- Justo Arines
- Universidade de Santiago de Compostela, Escola Universitaria de Optica e Optometria, Departamento de Fisica Aplicada, 15782 Santiago de Compostela, Spain.
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Cha D, Kim SK, Roh GH, Kim HM, Song JS. Effects of Eye Registration on the Astigmatism Correction in the Surface Laser Ablation. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2010. [DOI: 10.3341/jkos.2010.51.6.809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Deoksun Cha
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Sang Kyoon Kim
- Department of Ophthalmology, Hongseong Medical Center, Hongseong, Korea
| | | | - Hyo Myung Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Jong Suk Song
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
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Lee SB, Hwang BS, Lee J. Effects of decentration of photorefractive keratectomy on the induction of higher order wavefront aberrations. J Refract Surg 2009; 26:731-43. [PMID: 20027991 DOI: 10.3928/1081597x-20091209-01] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Accepted: 10/27/2009] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the effects of ablation decentration on the induction of higher order wavefront aberrations (HOAs) in active eye-tracker-assisted myopic photorefractive keratectomy (PRK) using the VISX STAR S4 laser with ActiveTrak (Abbott Medical Optics [AMO]). METHODS Ninety-four myopic eyes (53 patients) were divided into three groups according to ablation decentration (group 1, ≤0.15 mm, 20 eyes; group 2, >0.15 to ≤0.30 mm, 54 eyes; and group 3, >0.30 mm, 20 eyes). The distances of ablation centers from the centers of the entrance pupils were analyzed using corneal topography. Wavefront errors were measured preoperatively and at 6 months after PRK using a VISX WaveScan aberrometer (AMO). Statistical analysis was performed to assess the influence of ablation decentration on PRK-induced HOAs. RESULTS The mean decentration was 0.23±0.10 mm (range: 0.04 to 0.52 7 mm). The magnitude of all HOAs was significantly increased at 6 months postoperatively (P<.05). Increases in PRK-induced HOAs including total HOA, coma, and spherical aberration were significantly different among the three groups (P<.05). Statistically significant differences were noted between pairs of data in group 1 versus group 3 for total HOA (P=.015), coma (P=.038), and spherical aberration (P=.038), and group 2 versus group 3 for coma (P=.049). CONCLUSIONS Ablation decentration >0.30 mm from the center of the entrance pupil was associated with greater induction of total HOA, coma, and spherical aberration after PRK, as compared with ablation decentration <0.15 mm. In addition, ablation decentration has a more significant influence on coma-inducing effects.
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Affiliation(s)
- Sang-Bumm Lee
- Department of Ophthalmology, Yeungnam University College of Medicine, Daegu, Korea.
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