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Owusu S, Zaabaar E, Kwarteng MA, Ankamah S, Abowine JBV, Kyei S. Scheimpflug-Derived Keratometric, Pachymetric and Pachymetric Progression Indices in the Diagnosis of Keratoconus: A Systematic Review and Meta-Analysis. Clin Ophthalmol 2023; 17:3941-3964. [PMID: 38143558 PMCID: PMC10749111 DOI: 10.2147/opth.s436492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/07/2023] [Indexed: 12/26/2023] Open
Abstract
Scheimpflug Pentacam Tomography is becoming crucial in the diagnosis and monitoring of keratoconus, as well as in pre- and post-corneal refractive care, but there are still some inconsistencies surrounding its evidence base diagnostic outcome. Therefore, this study aimed at employing meta-analysis to systematically evaluate the keratometric, pachymetric, and pachymetric progression indices used in the diagnosis of Keratoconus. The review protocol was registered with PROSPERO (Identifier: CRD4202310058) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, MEDLINE, Web of Science, and EMBASE were used for data search, followed by a quality appraisal of the included studies using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Meta-analysis was conducted using the meta (6.5.0) and metafor (4.2.0) packages in R version 4.3.0, as well as Stata. A total of 32 studies were included in the analysis. All keratometry (K) readings (flattest meridian, K1; steepest meridian, K2, maximum, Kmax) were significantly steeper in keratoconic compared to normal eyes: [MD (95% CI)], K1 [2.67 (1.81; 3.52)], K1-back [-0.71 (-1.03; -0.39)], K1-front [4.06 (2.48; 5.63)], K2 [4.32 (2.89; 5.75)], K2-back [-1.25 (-1.68; -0.82)], K2-front [4.82 (1.88; 7.76)], Kmax [7.57 (4.80; 10.34)], and Kmean [2.80 (1.13; 4.47)]. Additionally, corneal thickness at the center, CCT [-61.19 (-73.79; -48.60)] and apex, pachy-apex [-41.86 (-72.64; -11.08)] were significantly thinner in keratoconic eyes compared to normal eyes. The pooled estimates for pachymetric progression index (PPI): PPImin [0.66 (0.43; 0.90)], PPImax [1.26 (0.87; 1.64)], PPIavg [0.90 (0.68; 1.12)], and Ambrosio relational thickness (ART): ARTmax [-242.77 (-288.86; -196.69)], and ARTavg [-251.08 (-308.76; -195.39)] revealed significantly more rapid pachymetric progression in keratoconic eyes than in normal eyes. The Pentacam Scheimpflug-derived keratometric, pachymetric, and pachymetric progression indices are good predictors in discriminating KC from normal eyes.
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Affiliation(s)
- Sandra Owusu
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | - Ebenezer Zaabaar
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Michael Agyemang Kwarteng
- Department of Optometry, Bindura University of Science Education, Bindura, Zimbabwe
- Discipline of Optometry, University of Kwazulu-Natal, Durban, South Africa
| | - Samuel Ankamah
- University of Ghana Library System, University of Ghana, Accra, Ghana
| | | | - Samuel Kyei
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
- Biomedical and Clinical Research Center, University of Cape Coast, Cape Coast, Ghana
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Montanino A, van Overbeeke S, Pandolfi A. Modeling the biomechanics of laser corneal refractive surgery. J Mech Behav Biomed Mater 2023; 145:105998. [PMID: 37418971 DOI: 10.1016/j.jmbbm.2023.105998] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/27/2023] [Accepted: 06/26/2023] [Indexed: 07/09/2023]
Abstract
We present a finite element model of the human cornea used to simulate corneal refractive surgery according to the three most diffused laser procedures, i. e., photo-refractive keratectomy (PRK), laser in-situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE). The geometry used for the model is patient-specific in terms of anterior and posterior surfaces of the cornea and intrastromal surfaces originated by the planned intervention. The customization of the solid model prior to finite element discretization avoids the struggling difficulties associated with the geometrical modification induced by cutting, incision and thinning. Important features of the model include the identification of the stress-free geometry and an adaptive compliant limbus to account for the surrounding tissues. By the way of simplification, we adopt a Hooke material model extended to the finite kinematics, and consider only the preoperative and short-term postoperative conditions, disregarding the remodeling and material evolution aspects typical of biological tissues. Albeit simple and incomplete, the approach demonstrates that the post-operative biomechanical state of the cornea, after the creation of a flap or the removal of a small lenticule, is strongly modified with respect to the preoperative state and characterized by displacement irregularities and stress localizations.
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Affiliation(s)
- Andrea Montanino
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Via Toledo 402, Napoli, Italy.
| | - Sanne van Overbeeke
- Department of Mechanical Engineering, University of Technology Eindhoven, 5612 AZ Eindhoven, The Netherlands.
| | - Anna Pandolfi
- Department of Civil and Environmental Engineering, Politecnico di Milano, 20133 Milano, Italy.
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Sudhir RR, Farhath Pattan H, Rathore M, Kuppuswamy Parthasarathy M, Padmanabhan P, Lakshminarayanan V. The effect of refractive surgery on blur thresholds. Indian J Ophthalmol 2020; 68:2998-3001. [PMID: 33229685 PMCID: PMC7856997 DOI: 10.4103/ijo.ijo_1512_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose: The aim of this study was to measure blur thresholds before and after refractive surgery. Methods: In this prospective cohort study conducted in a tertiary eye hospital in South India. Blur thresholds were measured for 30 young adult myopic patients 1 month prior to and after refractive surgery. Patients were asked to report three stages of blur, namely Detectable Blur (DB), Bothersome Blur (BB), and Non-resolvable Blur (NB). Blur was created by adding plus lenses (in steps of 0.12D) over their optimal subjective refraction. The blur judgments were made both monocularly and binocularly when looking through a 3 mm artificial pupil at one line above the best-corrected visual acuity. Results: A total of 30 participants were included in this study (mean age = 25.5 ± 3.8 (20–36) years; 77% female). The mean binocular preoperative blur of this group was: DB = 0.39 ± 0.26D, BB = 0.74 ± 0.28D and NB = 1.04 ± 0.42D. The corresponding mean binocular blur one-month post-operatively was DB = 0.46 ± 0.28D, BB = 0.83 ± 0.35D, and NB = 1.21 ± 0.44D. Although there was a marginal increase in the blur thresholds postoperatively, the difference was not statistically significant (DB: P = 0.320; BB: P = 0.229; NB: P = 0.054). Conclusion: All three blur thresholds showed an insignificant minimal increase at 1 month post-operatively suggesting that patients adapt to the induced blur following refractive surgery. A longer follow up would reveal how the adaptation to blur would change with time.
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Affiliation(s)
- Rachapalle Reddi Sudhir
- Department of Cornea & Refractive Surgery, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Hadiya Farhath Pattan
- Department of Cornea & Refractive Surgery, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Mehal Rathore
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, Affiliated to SASTRA University, Thanjavur, Tamil Nadu, India
| | | | - Prema Padmanabhan
- Department of Cornea & Refractive Surgery, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Vasudevan Lakshminarayanan
- School of Optometry and Vision Science, Departments of Physics, ECE and Systems Design Engineering, University of Waterloo, Canada
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Biscevic A, Bohac M, Ahmedbegovic-Pjano M, Pidro A, Bejdic N, Patel S. The relationship between patient age and residual refractive error after uneventful laser in situ keratomileusis for moderate-to-high hyperopia. Eur J Ophthalmol 2020; 31:1725-1732. [PMID: 32597207 DOI: 10.1177/1120672120937658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To determine if the manifest sphero-cylindrical residual refractive error, at various time points over a 12-month postop period after laser in situ keratomileusis (LASIK) was associated with patient age at time of surgery. METHODS Patients with moderate to high hyperopia (3.00-7.00 DS) and astigmatism ⩽2 DC underwent LASIK using Wavelight Allegretto Eye Q (400 Hz). Treatments were centered on corneal vertex, flaps were made with Moria M2 mechanical microkeratome. Pre-and postoperative uncorrected and corrected distant visual acuity, best corrected spherical equivalent (SEQ) were measured. Measurements were taken at 1 week, 1, 3, 6, and 12 months after the surgery. Target refraction was emmetropia. Total of 161 patients were treated. In binocular cases, data from the right eyes were included for analysis. In this article, we report on refraction data only. Raw data were subjected to several permutations to elicit any links between refractive outcomes and patient age. RESULTS The key findings were as follows y = postop SEQ (diopters), x = patient age (years), ln(x) = natural logarithm of patient age: At 1 month, y = x[0.049 -0.011.ln(x)] (R = -0.205, p = 0.001, n = 161). At 3 months, y = x[0.077 -0.017.ln(x)] (R = -0.355, p < 0.001, n = 161). At 6 months, y = x[0.088 -0.020.ln(x)] (R = -0.382, p < 0.001, n = 161). At 12 months, y = x[0.093 -0.021.ln(x)] (R = -0.409, p < 0.001, n = 161). There was no significant association between x and y at 1 week (p > 0.05). CONCLUSION Residual postop refractive error after LASIK for hyperopia has a logarithmic association with patient age at time of surgery. In younger patients there is tendency toward undercorrection, the opposite occurs in older patients and this persists 1 year after treatment.
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Affiliation(s)
- Alma Biscevic
- Eye Clinic "Svjetlost," Sarajevo, Bosnia and Herzegovina.,University Eye Hospital "Svjetlost" Zagreb, School of Medicine University of Rijeka, Zagreb, Croatia
| | - Maja Bohac
- Eye Clinic "Svjetlost," Sarajevo, Bosnia and Herzegovina.,University Eye Hospital "Svjetlost" Zagreb, School of Medicine University of Rijeka, Zagreb, Croatia
| | | | - Ajla Pidro
- Eye Clinic "Svjetlost," Sarajevo, Bosnia and Herzegovina
| | - Nita Bejdic
- Eye Clinic "Svjetlost," Sarajevo, Bosnia and Herzegovina
| | - Sudi Patel
- Eye Clinic "Svjetlost," Sarajevo, Bosnia and Herzegovina.,University Eye Hospital "Svjetlost" Zagreb, School of Medicine University of Rijeka, Zagreb, Croatia
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Alio JL, Abdelghany AA, Abdou AA, Maldonado MJ. Cataract surgery on the previous corneal refractive surgery patient. Surv Ophthalmol 2016; 61:769-777. [PMID: 27423631 DOI: 10.1016/j.survophthal.2016.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 11/26/2022]
Abstract
Cataract surgery in cases with previous corneal refractive surgery may be a major challenge for the ophthalmologist. The refractive outcome of the case deserves special attention in the preoperative planning process, which should be tailored for the type of prior refractive procedure: incisional, ablative under a flap, or on the corneal surface. Avoiding refractive surprise after cataract surgery in these cases is principally dependent on the accuracy of the intraocular lens calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases.
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Affiliation(s)
- Jorge L Alio
- Vissum Corporación, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain.
| | - Ahmed A Abdelghany
- Ophthalmology Department, Faculty of Medicine, Minia University, Minia, Egypt
| | - Ahmed A Abdou
- Ophthalmology Department, AUH, Assiut University, Assiut, Egypt
| | - M J Maldonado
- IOBA-Eye Institute, Valladolid, Spain; Division of Ophthalmology, University of Valladolid, Valladolid, Spain
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Kanellopoulos AJ, Asimellis G. Combined laser in situ keratomileusis and prophylactic high-fluence corneal collagen crosslinking for high myopia: two-year safety and efficacy. J Cataract Refract Surg 2016; 41:1426-33. [PMID: 26287881 DOI: 10.1016/j.jcrs.2014.10.045] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/24/2014] [Accepted: 10/10/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the safety, efficacy, and refractive and keratometric stability of myopic femtosecond laser in situ keratomileusis (LASIK) with concurrent prophylactic high-fluence corneal collagen crosslinking (CXL) compared with the outcomes of standard femtosecond LASIK. SETTING Private clinical practice, Athens, Greece. DESIGN Consecutive randomized prospective comparative study. METHODS Eyes that had myopic LASIK or myopic LASIK with concurrent high-fluence CXL were evaluated preoperatively and up to 2 years postoperatively for manifest refraction spherical equivalent (MRSE), refractive astigmatism, visual acuity, corneal keratometry (K), and endothelial cell count. RESULTS One hundred forty consecutive eyes had myopic LASIK; 65 of the eyes were treated additionally with CXL. In the LASIK-CXL eyes, the mean postoperative MRSE was -0.18 diopter (D) ± 17.0 (SD) from -6.67 ± 2.14 D preoperatively. The postoperative flat K was 37.67 D from 43.92 D, and the steep K was 38.38 D from 45.15 D. The correlation coefficient of SE correction predictability was 0.975. In the LASIK-only eyes, the mean postoperative MRSE was -0.32 ± 0.24 D from -5.49 ± 1.99 D preoperatively. The flat K was 38.04 D from 43.15 D, and the steep K was 38.69 D from 44.03 D. The correlation coefficient of SE correction predictability was 0.968. The differences between the 2 groups at the 20/20 and 20/25 levels were statistically significant (P = .045 and P = .039, respectively). CONCLUSION Two-year results indicate that the application of prophylactic CXL concurrently with high-myopic LASIK appears to improve refractive and keratometric stability, presumably by affecting corneal biomechanical properties. FINANCIAL DISCLOSURE Dr. Kanellopoulos is a consultant to Alcon Surgical, Inc., Wavelight Laser Technologie AG, Allergan, Inc., Avedro, Inc., and i-Optics Corp. Dr. Asimellis has no financial or proprietary interest in any material or method mentioned.
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MESH Headings
- Adolescent
- Adult
- Cell Count
- Collagen/metabolism
- Combined Modality Therapy
- Corneal Pachymetry
- Corneal Stroma/metabolism
- Cross-Linking Reagents
- Endothelium, Corneal/pathology
- Female
- Follow-Up Studies
- Humans
- Keratomileusis, Laser In Situ/methods
- Lasers, Excimer/adverse effects
- Lasers, Excimer/therapeutic use
- Male
- Myopia, Degenerative/drug therapy
- Myopia, Degenerative/physiopathology
- Myopia, Degenerative/surgery
- Myopia, Degenerative/therapy
- Photosensitizing Agents/adverse effects
- Photosensitizing Agents/therapeutic use
- Prospective Studies
- Refraction, Ocular/physiology
- Riboflavin/therapeutic use
- Surgical Flaps
- Tomography, Optical Coherence
- Treatment Outcome
- Visual Acuity/physiology
- Young Adult
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Affiliation(s)
- Anastasios John Kanellopoulos
- From Laservision.gr Eye Institute (Kanellopoulos, Asimellis), Athens, Greece; New York University Medical School (Kanellopoulos), New York, New York, USA.
| | - George Asimellis
- From Laservision.gr Eye Institute (Kanellopoulos, Asimellis), Athens, Greece; New York University Medical School (Kanellopoulos), New York, New York, USA
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Cavas-Martínez F, De la Cruz Sánchez E, Nieto Martínez J, Fernández Cañavate FJ, Fernández-Pacheco DG. Corneal topography in keratoconus: state of the art. EYE AND VISION 2016; 3:5. [PMID: 26904709 PMCID: PMC4762162 DOI: 10.1186/s40662-016-0036-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 02/14/2016] [Indexed: 11/12/2022]
Abstract
The morphological characterization of the cornea using corneal topographers is a widespread clinical practice that is essential for the diagnosis of keratoconus. The current state of this non-invasive exploratory technique has evolved with the possibility of achieving a great number of measuring points of both anterior and posterior corneal surfaces, which is possible due to the development of new and advanced measurement devices. All these data are later used to extract a series of topographic valuation indices that permit to offer the most exact and reliable clinical diagnosis. This paper describes the technologies in which current corneal topographers are based on, being possible to define the main morphological characteristics that the keratoconus pathology produces on corneal surface. Finally, the main valuation indices, which are provided by the corneal topographers and used for the diagnosis of keratoconus, are also defined.
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Affiliation(s)
- F Cavas-Martínez
- Department of Graphical Expression, Technical University of Cartagena, C/Doctor Fleming s/n, Cartagena, 30202, Murcia Spain
| | - E De la Cruz Sánchez
- Faculty of Sports Science, C/ Santa Alicia s/n, Santiago de la Ribera, 30720 Murcia, Spain
| | - J Nieto Martínez
- Department of Graphical Expression, Technical University of Cartagena, C/Doctor Fleming s/n, Cartagena, 30202, Murcia Spain
| | - F J Fernández Cañavate
- Department of Graphical Expression, Technical University of Cartagena, C/Doctor Fleming s/n, Cartagena, 30202, Murcia Spain
| | - D G Fernández-Pacheco
- Department of Graphical Expression, Technical University of Cartagena, C/Doctor Fleming s/n, Cartagena, 30202, Murcia Spain
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Edens C, Liebich L, Halpin AL, Moulton-Meissner H, Eitniear S, Zgodzinski E, Vasko L, Grossman D, Perz JF, Mohr MC. Mycobacterium chelonae Eye Infections Associated with Humidifier Use in an Outpatient LASIK Clinic--Ohio, 2015. MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT 2015; 64:1177. [PMID: 26492452 DOI: 10.15585/mmwr.mm6441a4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Laser-assisted in situ keratomileusis (LASIK) eye surgery is increasingly common, with approximately 600,000 procedures performed each year in the United States. LASIK eye surgery is typically performed in an outpatient setting and involves the use of a machine-guided laser to reshape the lens of the eye to correct vision irregularities. Clinic A is an ambulatory surgery center that performs this procedure on 1 day each month. On February 5, 2015, the Toledo-Lucas County Health Department (TLCHD) in Ohio was notified of eye infections in two of the six patients who had undergone LASIK procedures at clinic A on January 9, 2015. The two patients experienced eye pain after the procedures and received diagnoses of infection with Mycobacterium chelonae, an environmental organism found in soil and water.
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Kanellopoulos AJ, Asimellis G, Karabatsas C. Comparison of prophylactic higher fluence corneal cross-linking to control, in myopic LASIK, one year results. Clin Ophthalmol 2014; 8:2373-81. [PMID: 25473264 PMCID: PMC4251572 DOI: 10.2147/opth.s68372] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Purpose To compare 1-year results: safety, efficacy, refractive and keratometric stability, of femtosecond myopic laser-assisted in situ keratomileusis (LASIK) with and without concurrent prophylactic high-fluence cross-linking (CXL) (LASIK-CXL). Methods We studied a total of 155 consecutive eyes planned for LASIK myopic correction. Group A represented 73 eyes that were treated additionally with concurrent prophylactic high-fluence CXL; group B included 82 eyes subjected to the stand-alone LASIK procedure. The following parameters were evaluated preoperatively and up to 1-year postoperatively: manifest refractive spherical equivalent (MRSE), refractive astigmatism, visual acuity, corneal keratometry, and endothelial cell counts. We plotted keratometry measurements pre-operatively and its change in the early, interim and later post-operative time for the two groups, as a means of keratometric stability comparison. Results Group A (LASIK-CXL) had an average postoperative MRSE of −0.23, −0.19, and −0.19 D for the 3-, 6-, and 12-month period, respectively, compared to −6.58±1.98 D preoperatively. Flat keratometry was 37.69, 37.66, and 37.67 D, compared to 43.94 D preoperatively, and steep keratometry was 38.35, 38.36, and 38.37 D, compared to 45.17 D preoperatively. The predictability of Manifest Refraction Spherical Equivalent (MRSE) correction showed a correlation coefficient of 0.979. Group B (stand-alone LASIK) had an average postoperative MRSE of −0.23, −0.20, and −0.27 D for the 3-, 6-, and 12-month period, respectively, compared with −5.14±2.34 D preoperatively. Flat keratometry was 37.65, 37.89, and 38.02 D, compared with 43.15 D preoperatively, and steep keratometry was 38.32, 38.57, and 38.66 D, compared with 44.07 D preoperatively. The predictability of MRSE correction showed a correlation coefficient of 0.970. The keratometric stability plots were stable for the LASIK CXL group and slightly regressing in the standard LASIK group, a novel stability evaluation metric that may escape routine acuity and refraction measurements. Conclusion Application of prophylactic CXL concurrently with myopic LASIK surgery appears to contribute to improved refractive and keratometric stability compared to standard LASIK. The procedure appears safe and provides a new potential for LASIK correction.
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Affiliation(s)
- Anastasios John Kanellopoulos
- LaserVision.gr Clinical and Research Eye Institute, Athens, Greece ; New York University Medical School, New York, NY, USA
| | - George Asimellis
- LaserVision.gr Clinical and Research Eye Institute, Athens, Greece
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New-Generation Hybrid Contact Lens for the Management of Extreme Irregularity in a Thin Cornea After Unsuccessful Excimer Laser Refractive Surgery. Eye Contact Lens 2014; 40:e16-20. [DOI: 10.1097/icl.0b013e31829e8f90] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lim CHL, Riau AK, Lwin NC, Chaurasia SS, Tan DT, Mehta JS. LASIK following small incision lenticule extraction (SMILE) lenticule re-implantation: a feasibility study of a novel method for treatment of presbyopia. PLoS One 2013; 8:e83046. [PMID: 24349429 PMCID: PMC3859649 DOI: 10.1371/journal.pone.0083046] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/07/2013] [Indexed: 11/25/2022] Open
Abstract
Presbyopia remains a major visual impairment for patients, who have previously undergone laser refractive correction and enjoyed unaided distance vision prior to the onset of presbyopia. Corneal stromal volume restoration through small incision lenticule extraction (SMILE) lenticule re-implantation presents an opportunity for restoring the patients’ non-dominant eye to previous low myopia to achieve a monovision. In this study, we investigated the feasibility of performing LASIK after lenticule re-implantation as a method to create presbyopic monovision. A -6.00D SMILE correction was performed in 9 rabbit eyes. The lenticules were cryopreserved for 14 days and re-implanted. Five weeks later, 3 of these eyes underwent LASIK for -5.00D correction (RL group); 3 underwent LASIK flap creation, which was not lifted (RN); and no further procedures were performed on the remaining 3 eyes. These groups were compared with 3 eyes that underwent standard LASIK for a -5.00D correction (LO); 3 that underwent creation of non-lifted flap (LN); and 3 non-operated eyes. Rabbits were euthanized 1 day post-surgery. Tissue responses were analyzed by immunohistochemistry, slit lamp and in vivo confocal microscopy (IVCM). Intrastromal irregularities and elevated reflectivity levels of the excimer-ablated plane were observed on slit lamp and IVCM, respectively in the RL group. The results were comparable (P = 0.310) to IVCM findings in the LO group. RL and LO groups showed similar fibronectin expression levels, number of CD11b-positive cells (P = 0.304) and apoptotic cells (P = 0.198). There was no difference between the RN and LN groups in reflectivity levels (P = 0.627), fibronectin expression levels, CD11b-positive cells (P = 0.135) and apoptotic cells (P = 0.128). LASIK can be performed following lenticule re-implantation to create presbyopic monovision. The tissue responses elicited after performing LASIK on corneas that have undergone SMILE and subsequent lenticule re-implantation are similar to primary procedure.
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Affiliation(s)
- Chris H. L. Lim
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
- Singapore National Eye Centre, Singapore, Singapore
| | - Andri K. Riau
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Nyein C. Lwin
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Shyam S. Chaurasia
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Donald T. Tan
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
- Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jodhbir S. Mehta
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore, Singapore
- Singapore National Eye Centre, Singapore, Singapore
- Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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Laser in situ keratomileusis in United States Naval aviators. J Cataract Refract Surg 2013; 39:1047-58. [DOI: 10.1016/j.jcrs.2013.01.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/15/2013] [Accepted: 01/15/2013] [Indexed: 11/17/2022]
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Huang J, Lu W, Savini G, Hu L, Pan C, Wang J, Tan W, Chen J, Wang Q. Evaluation of corneal thickness using a Scheimpflug-Placido disk corneal analyzer and comparison with ultrasound pachymetry in eyes after laser in situ keratomileusis. J Cataract Refract Surg 2013; 39:1074-80. [PMID: 23680632 DOI: 10.1016/j.jcrs.2013.01.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/26/2013] [Accepted: 01/31/2013] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the repeatability and reproducibility of corneal thickness measurements in post-laser in situ keratomileusis (LASIK) eyes using a rotating Scheimpflug camera combined with a Placido disk corneal topographer (Sirius) and compare the results with those of ultrasound (US) pachymetry. SETTING Eye Hospital of Wenzhou Medical College, Wenzhou, China. DESIGN Comparative evaluation of a diagnostic test or technology. METHODS Patients were examined 3 times with the Scheimpflug-Placido topographer by 2 examiners. The central pupil corneal thickness (CTpupil), apical corneal thickness (CTapex), and thinnest corneal thickness (CTthinnest) were recorded. After noncontact examinations, US pachymetry was used to obtain the central corneal thickness (CCT). RESULTS The Scheimpflug-Placido topographer showed high intraoperator repeatability as indicated by a test-retest repeatability of less than 8.5 μm for CTpupil, CTapex, and CTthinnest, The coefficients of variation (CoV) were less than 0.7%, and the intraclass correlation coefficient was higher than 0.99. Excellent results were also obtained for interoperator reproducibility. All CoVs were less than 0.5%. The 95% limits of agreement between the Scheimpflug-Placido measurement and the US pachymetry measurements were narrow (-16.62 to 12.44 μm for CTpupil versus US pachymetry CCT; -17.49 to 12.16 μm for CTapex versus US pachymetry CCT; -18.59 to 10.90 μm for CTthinnest versus US pachymetry CCT). CONCLUSIONS The Scheimpflug-Placido topographer showed excellent intraoperator repeatability and interoperator reproducibility of CTpupil, CTapex, and CTthinnest measurements in post-LASIK eyes. The CCT measurements obtained using the device were in high agreement with those obtained by US pachymetry, suggesting that the 2 devices are interchangeable. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Jinhai Huang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, and the Key Laboratory of Vision Science, Ministry of Health PR China, Wenzhou, Zhejiang, China
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López-Miguel A, Martínez-Almeida L, González-García MJ, Coco-Martín MB, Sobrado-Calvo P, Maldonado MJ. Precision of higher-order aberration measurements with a new Placido-disk topographer and Hartmann-Shack wavefront sensor. J Cataract Refract Surg 2012; 39:242-9. [PMID: 23142546 DOI: 10.1016/j.jcrs.2012.08.061] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 08/24/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE To assess the intrasession and intersession precision of ocular, corneal, and internal higher-order aberrations (HOAs) measured using an integrated topographer and Hartmann-Shack wavefront sensor (Topcon KR-1W) in refractive surgery candidates. SETTING IOBA-Eye Institute, Valladolid, Spain. DESIGN Evaluation of diagnostic technology. METHODS To analyze intrasession repeatability, 1 experienced examiner measured eyes 9 times successively. To study intersession reproducibility, the same clinician obtained measurements from another set of eyes in 2 consecutive sessions 1 week apart. Ocular, corneal, and internal HOAs were obtained. Coma and spherical aberrations, 3rd- and 4th-order aberrations, and total HOAs were calculated for a 6.0 mm pupil diameter. RESULTS For intrasession repeatability (75 eyes), excellent intraclass correlation coefficients (ICCs) were obtained (ICC >0.87), except for internal primary coma (ICC = 0.75) and 3rd-order (ICC = 0.72) HOAs. Repeatability precision (1.96 × S(w)) values ranged from 0.03 μm (corneal primary spherical) to 0.08 μm (ocular primary coma). For intersession reproducibility (50 eyes), ICCs were good (>0.8) for ocular primary spherical, 3rd-order, and total higher-order aberrations; reproducibility precision values ranged from 0.06 μm (corneal primary spherical) to 0.21 μm (internal 3rd order), with internal HOAs having the lowest precision (≥0.12 μm). No systematic bias was found between examinations on different days. CONCLUSIONS The intrasession repeatability was high; therefore, the device's ability to measure HOAs in a reliable way was excellent. Under intersession reproducibility conditions, dependable corneal primary spherical aberrations were provided. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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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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Patel NB, Garcia B, Harwerth RS. Influence of anterior segment power on the scan path and RNFL thickness using SD-OCT. Invest Ophthalmol Vis Sci 2012; 53:5788-98. [PMID: 22836769 DOI: 10.1167/iovs.12-9937] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Retinal nerve fiber layer (RNFL) thickness measures with spectral domain-optical coherence tomography (SD-OCT) provide important information on the health of the optic nerve. As with most retinal imaging technologies, ocular magnification characteristics of the eye must be considered for accurate analysis. While effects of axial length have been reported, the effects of anterior segment optical power on RNFL thickness measures have not been described fully to our knowledge. The purpose of our study was to determine the influence of the optical power change at the anterior corneal surface, using contact lenses, on the location of the scan path and measurements of RNFL thickness in normal healthy eyes. METHODS We recruited 15 normal subjects with less than 6 diopters (D) of ametropia and no ocular pathology. One eye of each subject was selected randomly for scanning. Baseline SD-OCT scans included raster cubes centered on the optic nerve and macula, and a standard 12-degree diameter RNFL scan. Standard 12-degree RNFL scans were repeated with 10 separate contact lenses, (Proclear daily, Omafilcon A/60%) ranging from +8 to -12 D in 2-D steps. The extent of the retinal scan, and RNFL thickness and area measures were quantified using custom MATLAB programs that included ocular biometry measures (IOL Master). RESULTS RNFL thickness decreased (0.52 μm/D, r = -0.33, P < 0.01) and the retinal region scanned increased (0.52%/D, r = 0.97, P < 0.01) with increase in contact lens power (-12 to +8). The normalized/percentage rates of change of RNFL thickness (-0.11/mm, r = -0.67, P < 0.01) and image size (0.11/mm, r = 0.96, P < 0.01) were related to axial length. Changes in the retinal region scanned were in agreement with transverse scaling, computed with a three surface schematic eye (R(2) = 0.97, P < 0.01). RNFL area measures, that incorporated the computed transverse scaling, were not related significantly to contact lens power (863 μm(2)/D, r = 0.06, P = 0.47). CONCLUSIONS Measurements of RNFL thickness by SD-OCT are dependent on the optics of the eye, including anterior segment power and axial length. The relationships between RNFL thickness measures and optical power are a direct reflection of scan path location with respect to the optic nerve head rim, caused by relative magnification. An incorporation of transverse scaling to RNFL area measures, based on individualized ocular biometry, eliminated the magnification effect.
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Affiliation(s)
- Nimesh B Patel
- University of Houston, College of Optometry, Houston, Texas 77204, USA.
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López-Miguel A, Correa-Pérez ME, Miranda-Anta S, Iglesias-Cortiñas D, Coco-Martín MB, Maldonado MJ. Comparison of central corneal thickness using optical low-coherence reflectometry and spectral-domain optical coherence tomography. J Cataract Refract Surg 2012; 38:758-64. [DOI: 10.1016/j.jcrs.2011.11.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 11/14/2011] [Accepted: 11/18/2011] [Indexed: 11/26/2022]
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Piñero DP, Pérez-Cambrodí RJ, Gómez-Hurtado A, Blanes-Mompó FJ, Alzamora-Rodríguez A. Results of laser in situ keratomileusis performed using solid-state laser technology. J Cataract Refract Surg 2012; 38:437-44. [PMID: 22244611 DOI: 10.1016/j.jcrs.2011.09.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 09/09/2011] [Accepted: 09/12/2011] [Indexed: 11/18/2022]
Abstract
PURPOSE To evaluate and report the visual, refractive, and aberrometry outcomes of laser in situ keratomileusis (LASIK) to correct low to moderate myopia using a commercial solid-state laser. SETTING Oftalmar, Medimar International Hospital, Alicante, Spain. DESIGN Prospective case series. METHODS This study evaluated consecutive eyes with low to moderate myopia that had LASIK performed using a Pulzar Z1 solid-state laser. Visual, refractive, and aberrometry changes as well as potential complications were evaluated. RESULTS The study enrolled 60 eyes (34 patients). The mean follow-up was 8.5 months (range 6 to 13 months). There was a significant improvement in logMAR uncorrected distance visual acuity (UDVA) postoperatively (P<.01). No significant change was detected in logMAR corrected distance visual acuity (CDVA) (P=.21). The postoperative logMAR UDVA was 0.1 (approximately 20/25) or better in 57 eyes (95.00%). The mean overall efficacy index was 0.99 and the mean safety index, 1.02. Postoperatively, 1 eye (1.67%) lost lines (1 line) of CDVA. The postoperative spherical equivalent was within ± 0.50 diopter in 58 eyes (96.67%). There was a small, but statistically significant increase in the primary coma root mean square (0.17 μm) and in the magnitude of primary spherical aberration (0.09 μm). No severe complications occurred. CONCLUSION Laser in situ keratomileusis using the solid-state laser provided predictable correction of low to moderate myopia, minimizing the induction of higher-order aberrations and preserving CDVA. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- David P Piñero
- Alicante Oftalmológica, Oftalmar, Hospital Internacional Medimar, Alicante, Spain.
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Osman E. Laser refractive surgery in glaucoma patients. Saudi J Ophthalmol 2011; 25:169-73. [PMID: 23960918 PMCID: PMC3729399 DOI: 10.1016/j.sjopt.2010.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/10/2010] [Accepted: 04/18/2010] [Indexed: 11/22/2022] Open
Abstract
Glaucoma may not be an absolute contraindication to Laser-Assisted in situ Keratomileusis (LASIK), but so far it is a relative one. People who are glaucoma suspects or who have glaucoma are just as likely as any other to seek laser refractive surgery. LASIK is a popular ocular procedure, relatively pain free and it is carried out with an extremely precise computer-controlled excimer laser emission. On the other hand, glaucoma is a group of diseases manifested by optic nerve damage with visual field changes. Patients that undergo a transient but significant rise in intraocular pressure during LASIK procedure have risk of further optic nerve damage. Furthermore, steroids which are typically used after refractive surgery can increase intraocular pressure (IOP) especially in steroid responders, who are more prevalent among glaucoma patient. Glaucoma patients interested in LASIK surgery may visit a glaucoma specialist or another LASIK surgeon who has had experience with performing LASIK in glaucoma patients. PRK (photorefractive keratectomy), LASEK (laser epithelial keratomileusis) are good alternatives for glaucoma patients. Refractive surgeons might want to consider giving patients a photo of their optic nerve, or a drawing, or an objective record of their preoperative examination.
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Affiliation(s)
- Essam Osman
- Department of Ophthalmology, King Abdulaziz University Hospital (KAUH), Riyadh, Saudi Arabia
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Osman EA, Al-Saleh AA. Immediate changes in pupil size following Laser in situ keratomileusis (LASIK): Pupillometry study. Saudi J Ophthalmol 2010; 24:139-41. [DOI: 10.1016/j.sjopt.2010.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 06/07/2010] [Accepted: 06/08/2010] [Indexed: 10/19/2022] Open
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Aristeidou AP, Labiris G, Paschalis EI, Foudoulakis NC, Koukoula SC, Kozobolis VP. Evaluation of the retinal nerve fiber layer measurements, after photorefractive keratectomy and laser in situ keratomileusis, using scanning laser polarimetry (GDX VCC). Graefes Arch Clin Exp Ophthalmol 2010; 248:731-6. [PMID: 20072786 DOI: 10.1007/s00417-009-1273-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 11/30/2009] [Accepted: 12/07/2009] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND To evaluate the impact of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), on retinal nerve fiber layer (RNFL) measurements, by means of scanning laser polarimetry (SLP) GDx VCC (with variable corneal compensation). METHODS Two groups of 119 myopic patients each were treated by PRK and LASIK respectively; one eye of each patient was randomly selected for the study. RNFL measurements (around the entire calculation circle) was performed in all eyes 1 day before and 1, 3, 6 and 12 months after treatment by using SLP GDx VCC. Corneal compensation was performed in all eyes preoperatively, and in every examination step postoperatively, in order to neutralize the new corneal birefringence. RESULTS No statistical differences were found between the PRK and LASIK groups, in all preoperative and postoperative RNFL measurements. Only the p values for CCT and mean K-readings preoperatively were statistically significant. CONCLUSIONS PRK and LASIK do not seem to influence the RNFL measurements at 1st, 3rd, 6th and 12th postoperative months when measured with SLP GDx VCC. The corneal compensation reset is necessary in every step of the examination in order to have reproducible results.
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Affiliation(s)
- Antonios P Aristeidou
- Department of Ophthalmology & Eye Institute of Thrace, Democritus University of Thrace, Alexandroupolis, Greece.
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Osman EA, Alsaleh AA, Al Turki T, Al Obeidan SA. Bilateral acute angle closure glaucoma after hyperopic LASIK correction. Saudi J Ophthalmol 2009; 23:215-7. [PMID: 23960863 DOI: 10.1016/j.sjopt.2009.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 07/13/2009] [Indexed: 11/19/2022] Open
Abstract
Acute angle closure glaucoma is unexpected complication following laser in situ keratomileusis (LASIK). We are reporting a 49-years-old lady that was presented to the emergency department with acute glaucoma in both eyes soon after LASIK correction. Diagnosis was made on detailed clinical history and examination, slit lamp examination, intraocular pressure measurement and gonioscopy. Laser iridotomy in both eyes succeeded in controlling the attack and normalizing the intraocular pressure (IOP) more than 6 months of follow-up. Prophylactic laser iridotomy is essential for narrow angle patients before LASIK surgery if refractive laser surgery is indicated.
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Affiliation(s)
- Essam A Osman
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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