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Srujana D, Singh R, Titiyal JS, Sinha R. Assessment of posture-induced cyclotorsion during cataract surgery using the Verion image-guided system. Med J Armed Forces India 2020; 77:293-296. [PMID: 34305282 DOI: 10.1016/j.mjafi.2020.08.014] [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: 10/27/2017] [Accepted: 08/29/2020] [Indexed: 10/23/2022] Open
Abstract
Background The purpose of this prospective observational study is to analyse posture-induced cyclotorsion in eyes undergoing conventional phacoemulsification with toric intraocular lens (IOL) implantation and femtolaser-assisted cataract surgery (FLACS) using the Verion image-guided system. Methods Cyclotorsion was assessed in patients who underwent conventional phacoemulsification with toric IOL implantation and FLACS between June 2017 and November 2017 with registration of iris architecture, limbal and bulbar conjunctival blood vessels acquired preoperatively using the Verion Reference Unit (the patient in sitting position) and intraoperatively under the microscope using the digital marker of the Verion image-guided system with the patient in supine position. Results Forty-four eyes of 30 patients (21 men and 9 women) were included with the mean age of 56.5 ± 17.1 (range, 19-89; median, 62) years. The mean cyclotorsion induced by change in posture from sitting to supine position was 5.84 ± 3.25° (range, 1-17; median, 5). Overall, clockwise (CW) rotation (59.1%) was noted to be more common than counter clockwise (CCW) rotation (40.9%). Furthermore, CW rotation was more common in men than in women, and CCW rotation was significantly more common in women. Patients who underwent bilateral sequential cataract surgery show similar cyclorotation (CW or CCW) in both eyes more often than mixed rotation (85.7% vs 14.3%). Conclusion Significant cyclotorsion can occur in supine position during cataract surgery. Accurate assessment of the amount and direction of cyclotorsion aids in appropriate alignment of the toric IOL for optimal visual outcomes.
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Affiliation(s)
- Dubbaka Srujana
- Associate Professor, Dept of Ophthalmology, Armed Forces Medical College, Pune, India
| | - Reena Singh
- Senior Resident, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Jeewan S Titiyal
- Professor & HOD, Cornea, Lens & Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Sinha
- Professor, Cornea, Lens & Refractive Surgery Services, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Posture-related ocular cyclotorsion during cataract surgery with an ocular registration system. Sci Rep 2020; 10:2136. [PMID: 32034232 PMCID: PMC7005750 DOI: 10.1038/s41598-020-59118-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/23/2020] [Indexed: 12/03/2022] Open
Abstract
Ocular cyclotorsion when a patient changes from seated to supine position in cataract surgery and factors predicting the amount of cyclotorsion were investigated using VERION system. Variables analyzed were age, gender, preoperative visual acuity, axial length, laterality of eyes, operative duration, and the direction and degree of cyclotorsion. The mean cyclotorsion of 107 eyes of 93 cataract patients was 0.98 ± 4.85 degrees (median, 1 degree; range, -11 to 12 degrees), and the median absolute value was 4 degrees (mean, 4.05 ± 2.82 degrees; range, 0 to 12 degrees). Cyclotorsion was ≥3 degrees in 68 (63.6%) eyes. Excyclotorsion occurred more frequently than incyclotorsion (50.5% vs. 43.0%). There was no cyclotorsion in seven (6.5%). Multiple regression analysis showed that gender was a significant predictive factor for the absolute value of cyclotorsion (β = 1.06, P = 0.041); however, the other variables had no effect on cyclotorsion. The absolute value of cyclotorsion was significantly larger in female than in male patients [median, 4 degrees and 3 degrees, respectively; mean, 4.66 ± 3.02 degrees and 3.44 ± 2.52 degrees, respectively (P = 0.039)]. In conclusion, cataract patients had significant posture-related ocular cyclotorsion. The amount of cyclotorsion was larger for female than male patients.
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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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Lee JJ, Kim MK, Wee WR. Effect of Iris registration on visual outcome in wavefront-guided LASEK for myopic astigmatism. Int Ophthalmol 2017; 38:513-525. [PMID: 28285388 DOI: 10.1007/s10792-017-0486-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 03/04/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE This study aimed to investigate the effect of iris registration (IR) on visual outcomes in wavefront-guided LASEK for myopic astigmatism. METHODS The retrospective chart review was performed for wavefront-guided LASEK using VISX Star S4 in patients with myopic astigmatism (cylinder ≥ 1.00 diopter[D]). Eyes were divided into IR group (LASEK with IR at the time of surgery) and Non-IR group (LASEK without IR system + failed-IR engagement during LASEK). Visual acuity (VA), astigmatism, higher-order aberration (HOA), and contrast sensitivity were assessed preoperatively and 3 months postoperatively. The IR and Non-IR groups were subcategorized depending on the spherical equivalent (lower myopia ≤-5.00 D vs. higher myopia >-5.00 D) for the comparison of HOA changes. RESULTS Postoperative uncorrected VAs showed no differences between IR (n = 30) and Non-IR (n = 46). In astigmatic vector analyses, no differences were noted in the mean magnitude of error and the mean angle of error between two groups. There were no differences in postoperative total HOA, spherical aberration (SA), coma, and trefoil between the groups, either. The total HOA and SA increased in both groups, while coma increased only in Non-IR. In higher myopia, ΔRMS of coma was smaller in IR. Preoperative and postoperative total HOA were linearly correlated in Non-IR, but not for IR. Contrast sensitivity of 12 cycles per degree improved in both groups. CONCLUSION IR had similar outcomes to conventional trackers in wavefront-guided LASEK, with less tendency of inducing coma, especially in higher myopia.
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Affiliation(s)
- Jong Joo Lee
- Department of Ophthalmology, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Mee Kum Kim
- Department of Ophthalmology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea. .,Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea.
| | - Won Ryang Wee
- Department of Ophthalmology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.,Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea
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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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Prickett AL, Bui K, Hallak J, Bakhtiyari P, de la Cruz J, Azar DT, Chamon W. Cyclotorsional and non-cyclotorsional components of eye rotation observed from sitting to supine position. Br J Ophthalmol 2014; 99:49-53. [DOI: 10.1136/bjophthalmol-2014-304975] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bedell HE, Stevenson SB. Eye movement testing in clinical examination. Vision Res 2013; 90:32-7. [PMID: 23416869 DOI: 10.1016/j.visres.2013.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 11/30/2022]
Abstract
The clinical vision examination routinely includes an evaluation of ocular motor function. In a number of diverse situations, thorough objective recording of eye movements is warranted, using any of a variety of eye-tracking technologies that are available currently to clinicians. Here we review the clinical uses of eye tracking, with both an historical and contemporary view. We also consider several new imaging technologies that are becoming available in clinics and include inbuilt eye-tracking capability. These highly sensitive eye trackers should be useful for evaluating a variety of subtle, but important, oculomotor signs and disorders.
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Affiliation(s)
- Harold E Bedell
- College of Optometry, University of Houston, Houston, TX 77204-2020, USA.
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Liu YL, Yeh PT, Huang JY, Wang IJ, Chen WL, Hu FR, Hou YC. Pupil centroid shift and cyclotorsion in bilateral wavefront-guided laser refractive surgery and the correlation between both eyes. J Formos Med Assoc 2013; 112:64-71. [DOI: 10.1016/j.jfma.2012.02.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 02/26/2012] [Accepted: 02/29/2012] [Indexed: 11/28/2022] Open
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López-Miguel A, Maldonado MJ, Belzunce A, Barrio-Barrio J, Coco-Martín MB, Nieto JC. Precision of a commercial hartmann-shack aberrometer: limits of total wavefront laser vision correction. Am J Ophthalmol 2012; 154:799-807.e5. [PMID: 22902046 DOI: 10.1016/j.ajo.2012.04.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the intrasession and intersession precision of higher-order aberrations (HOAs) measured using a commercial Hartmann-Shack wavefront sensor (Zywave; Bausch & Lomb) in refractive surgery candidates. DESIGN Prospective, experimental study of a device. METHODS To analyze intrasession repeatability, 1 experienced examiner measured 30 healthy eyes 5 times successively. To study intersession reproducibility, the same clinician obtained measurements from another 30 eyes in 2 consecutive sessions at the same time of day 1 week apart. RESULTS For intrasession repeatability, excellent intraclass correlation coefficients (ICCs) were obtained for total ocular aberrations, total HOAs, and second-order terms (ICC, > 0.94). The ICCs for third-order terms also were high (ICCs, > 0.87); however, fourth-order ICCs varied from 0.71 to 0.90 (Z(4)(0) = 0.90); and fifth-order ICCs were less than 0.85. For intersession reproducibility, only total ocular aberrations, total ocular HOAs, second-order terms, Z(4)(0), Z(3)(1), and Z(3-)(3) had ICCs of 0.90 or more. Bland-Altman analysis showed that the limits of agreement (were clinically too wide for most higher-order Zernike terms, especially for the third-order terms (> 0.21 μm). CONCLUSIONS Total ocular aberrations, total HOAs, and second-order terms can be measured reliably by Zywave aberrometry without anatomic recognition. Third-order terms and Z(4)(0) are repeatable, but not as reproducible between visits. Fourth-order terms, except for Z(4)(0), and fifth-order terms are not sufficiently reliable for clinical decision making or treatment. Because the variability of Zywave can be a major limitation of a truly successful wavefront-guided excimer laser procedure, surgeons should consider treating HOA magnitudes that are more than the intrasession repeatability values (2.77 × S(w)) as those presented in this study.
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Narváez J, Brucks M, Zimmerman G, Bekendam P, Bacon G, Schmid K. Intraoperative Cyclorotation and Pupil Centroid Shift During LASIK and PRK. J Refract Surg 2012; 28:353-7. [DOI: 10.3928/1081597x-20120124-03] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 11/11/2011] [Indexed: 11/20/2022]
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Chen X, Stojanovic A, Stojanovic F, Eidet JR, Raeder S, Øritsland H, Utheim TP. Effect of limbal marking prior to laser ablation on the magnitude of cyclotorsional error. J Refract Surg 2012; 28:358-62. [PMID: 22421093 DOI: 10.3928/1081597x-20120221-02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 01/01/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the residual registration error after limbal-marking-based manual adjustment in cyclotorsional tracker-controlled laser refractive surgery. METHODS Two hundred eyes undergoing custom surface ablation with the iVIS Suite (iVIS Technologies) were divided into limbal marked (marked) and non-limbal marked (unmarked) groups. Iris registration information was acquired preoperatively from all eyes. Preoperatively, the horizontal axis was recorded in the marked group for use in manual cyclotorsional alignment prior to surgical iris registration. During iris registration, the preoperative iris information was compared to the eye-tracker captured image. The magnitudes of the registration error angle and cyclotorsional movement during the subsequent laser ablation were recorded and analyzed. RESULTS Mean magnitude of registration error angle (absolute value) was 1.82°±1.31° (range: 0.00° to 5.50°) and 2.90°±2.40° (range: 0.00° to 13.50°) for the marked and unmarked groups, respectively (P<.001). Mean magnitude of cyclotorsional movement during the laser ablation (absolute value) was 1.15°±1.34° (range: 0.00° to 7.00°) and 0.68°±0.97° (range: 0.00° to 6.00°) for the marked and unmarked groups, respectively (P=.005). Forty-six percent and 60% of eyes had registration error >2°, whereas 22% and 20% of eyes had cyclotorsional movement during ablation >2° in the marked and unmarked groups, respectively. CONCLUSIONS Limbal-marking-based manual alignment prior to laser ablation significantly reduced cyclotorsional registration error. However, residual registration misalignment and cyclotorsional movements remained during ablation.
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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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Wang TJ, Lin YH, Chang DCK, Chou HC, Wang IJ. Comparison of the effects of cylindrical correction with and without iris recognition technology in wavefront laser-assisted in situ keratomileusis. Clin Exp Ophthalmol 2011; 40:239-46. [DOI: 10.1111/j.1442-9071.2011.02614.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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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Gimeno FL, Chan CM, Li L, Tan DT, Mehta JS. Comparison of eye-tracking success in laser in situ keratomileusis after flap creation with 2 femtosecond laser models. J Cataract Refract Surg 2011; 37:538-43. [DOI: 10.1016/j.jcrs.2010.10.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 08/31/2010] [Accepted: 10/05/2010] [Indexed: 11/17/2022]
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Febbraro JL, Koch DD, Khan HN, Saad A, Gatinel D. Detection of static cyclotorsion and compensation for dynamic cyclotorsion in laser in situ keratomileusis. J Cataract Refract Surg 2010; 36:1718-23. [DOI: 10.1016/j.jcrs.2010.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 05/18/2010] [Accepted: 05/20/2010] [Indexed: 12/01/2022]
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Shen EP, Chen WL, Hu FR. Manual limbal markings versus iris-registration software for correction of myopic astigmatism by laser in situ keratomileusis. J Cataract Refract Surg 2010; 36:431-6. [DOI: 10.1016/j.jcrs.2009.10.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 09/13/2009] [Accepted: 10/21/2009] [Indexed: 11/30/2022]
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Prakash G, Ashok Kumar D, Agarwal A, Jacob S, Sarvanan Y, Agarwal A. Predictive factor analysis for successful performance of iris recognition-assisted dynamic rotational eye tracking during laser in situ keratomileusis. Am J Ophthalmol 2010; 149:229-237.e2. [PMID: 19896632 DOI: 10.1016/j.ajo.2009.08.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 11/17/2022]
Abstract
PURPOSE To analyze the predictive factors associated with success of iris recognition and dynamic rotational eye tracking on a laser in situ keratomileusis (LASIK) platform with active assessment and correction of intraoperative cyclotorsion. DESIGN Interventional case series. METHODS Two hundred seventy-five eyes of 142 consecutive candidates underwent LASIK with attempted iris recognition and dynamic rotational tracking on the Technolas 217z100 platform (Techolas Perfect Vision, St Louis, Missouri, USA) at a tertiary care ophthalmic hospital. The main outcome measures were age, gender, flap creation method (femtosecond, microkeratome, epi-LASIK), success of static rotational tracking, ablation algorithm, pulses, and depth; preablation and intraablation rotational activity were analyzed and evaluated using regression models. RESULTS Preablation static iris recognition was successful in 247 eyes, without difference in flap creation methods (P = .6). Age (partial correlation, -0.16; P = .014), amount of pulses (partial correlation, 0.39; P = 1.6 x 10(-8)), and gender (P = .02) were significant predictive factors for the amount of intraoperative cyclodeviation. Tracking difficulties leading to linking the ablation with a new intraoperatively acquired iris image were more with femtosecond-assisted flaps (P = 2.8 x 10(-7)) and the amount of intraoperative cyclotorsion (P = .02). However, the number of cases having nonresolvable failure of intraoperative rotational tracking was similar in the 3 flap creation methods (P = .22). CONCLUSIONS Intraoperative cyclotorsional activity depends on the age, gender, and duration of ablation (pulses delivered). Femtosecond flaps do not seem to have a disadvantage over microkeratome flaps as far as iris recognition and success of intraoperative dynamic rotational tracking is concerned.
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Affiliation(s)
- Gaurav Prakash
- Dr Agarwal's Eye Hospital and Eye Research Centre, 19 Cathedral Road, Chennai, India
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Bucher C, Zuberbuhler B, Goggin M, Esterman A, Schipper I. Corneal limbal marking in the treatment of myopic astigmatism with the excimer laser. J Refract Surg 2009; 26:505-11. [PMID: 19715268 DOI: 10.3928/1081597x-20090814-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 07/23/2009] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine whether preoperative marking of the limbal cornea improves treatment of myopic astigmatism with the excimer laser. METHODS Retrospective study on 108 eyes with myopic astigmatism that underwent LASIK or laser epithelial keratomileusis (LASEK) with the Technolas 217 (Bausch & Lomb) excimer laser. Preoperative limbal marking was performed in 47 eyes (marked group). The 12-month results were used for refractive and visual analysis. RESULTS The achieved cylinder reduction, spherical reduction, and refractive predictability were similar for the marked and unmarked groups in the overall study collective, in the LASIK and LASEK subgroup analysis, and in a higher astigmatism (> 1.25 diopters) subgroup analysis. Limbal marking showed no influence on the refractive results, and vector analysis showed no significant difference in angle of error among groups. CONCLUSIONS Corneal limbal marking failed to improve the refractive outcome in LASIK and LASEK for myopic astigmatism.
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Effect of Iris Registration on Outcomes of LASIK for Myopia With the VISX CustomVue Platform. J Refract Surg 2009; 25:493-502. [DOI: 10.3928/1081597x-20090512-03] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chang J. Cyclotorsion during laser in situ keratomileusis. J Cataract Refract Surg 2008; 34:1720-6. [DOI: 10.1016/j.jcrs.2008.06.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
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Tantayakom T, Lim JN, Purcell TL, Nalgirkar A, Cheng L, Schanzlin DJ. Visual outcomes after wavefront-guided laser in situ keratomileusis with and without iris registration. J Cataract Refract Surg 2008; 34:1532-7. [DOI: 10.1016/j.jcrs.2008.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 05/19/2008] [Indexed: 10/21/2022]
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Ocular cyclotorsion according to body position and flap creation before laser in situ keratomileusis. J Cataract Refract Surg 2008; 34:557-61. [DOI: 10.1016/j.jcrs.2007.11.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 11/11/2007] [Indexed: 11/19/2022]
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Ghosh S, Couper TA, Lamoureux E, Jhanji V, Taylor HR, Vajpayee RB. Evaluation of iris recognition system for wavefront-guided laser in situ keratomileusis for myopic astigmatism. J Cataract Refract Surg 2008; 34:215-21. [DOI: 10.1016/j.jcrs.2007.09.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 09/02/2007] [Indexed: 10/22/2022]
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De Santis A, Iacoviello D. Optimal segmentation of pupillometric images for estimating pupil shape parameters. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2006; 84:174-87. [PMID: 16934907 DOI: 10.1016/j.cmpb.2006.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 07/20/2006] [Accepted: 07/20/2006] [Indexed: 05/11/2023]
Abstract
The problem of determining the pupil morphological parameters from pupillometric data is considered. These characteristics are of great interest for non-invasive early diagnosis of the central nervous system response to environmental stimuli of different nature, in subjects suffering some typical diseases such as diabetes, Alzheimer disease, schizophrenia, drug and alcohol addiction. Pupil geometrical features such as diameter, area, centroid coordinates, are estimated by a procedure based on an image segmentation algorithm. It exploits the level set formulation of the variational problem related to the segmentation. A discrete set up of this problem that admits a unique optimal solution is proposed: an arbitrary initial curve is evolved towards the optimal segmentation boundary by a difference equation; therefore no numerical approximation schemes are needed, as required in the equivalent continuum formulation usually adopted in the relevant literature.
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Affiliation(s)
- A De Santis
- Dept. of Informatica e Sistemistica, University "La Sapienza" of Rome, via Eudossiana 18, 00184 Rome, Italy
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