Ectasia risk factors in refractive surgery

Santhiago, Marcony R.; Giacomin, Natalia T; Smadja, David; Bechara, Samir Jacob

doi:10.2147/opth.s51313

Cited by 114 publications

(100 citation statements)

References 66 publications

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“…For example, a minimum corneal thickness of 480 μ m is necessary to minimize the risk of ectasia after laser in situ keratomileusis (LASIK) [1]. Corneal curvature is required for all intraocular lens (IOL) formulas and thus influences the power of the selected IOL [2].…”

Section: Introductionmentioning

confidence: 99%

Repeatability and Agreement of Central Corneal Thickness and Keratometry Measurements between Four Different Devices

Kiraly¹,

Stange

Kunert

et al. 2017

Journal of Ophthalmology

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Background. To estimate repeatability and comparability of central corneal thickness (CCT) and keratometry measurements obtained by four different devices in healthy eyes. Methods. Fifty-five healthy eyes from 55 volunteers were enrolled in this study. CCT (IOLMaster 700, Pentacam HR, and Cirrus HD-OCT) and keratometry readings (IOLMaster 700, Pentacam HR, and iDesign) were measured. For statistical analysis, the corneal spherocylinder was converted into power vectors (J0, J45). Repeatability was assessed by intraclass correlation coefficient (ICC). Agreement of measurements between the devices was evaluated by the Bland-Altman method. Results. The analysis of repeatability of CCT data of IOLMaster 700, Pentacam HR, and Cirrus HD-OCT showed high ICCs (range 0.995 to 0.999). The comparison of CCT measurements revealed statistically significant differences between Pentacam HR versus IOLMaster 700 (p < 0.0001) and Pentacam HR versus Cirrus HD-OCT (p < 0.0001), respectively. There was no difference in CCT measurements between IOLMaster 700 and Cirrus HD-OCT (p = 0.519). The repeatability of keratometry readings (J0 and J45) of IOLMaster 700, Pentacam HR, and iDesign was also high with ICCs ranging from 0.974 to 0.999. The Pentacam HR revealed significantly higher J0 in comparison to IOLMaster 700 (p = 0.009) and iDesign (p = 0.041); however, no significant difference was between IOLMaster 700 and iDesign (p = 0.426). Comparison of J45 showed no significant difference between IOLMaster 700, Pentacam HR, and iDesign. These results were in accordance with Bland-Altman plots. Conclusion. In clinical practice, the devices analyzed should not be used interchangeably due to low agreement regarding CCT as well as keratometry readings.

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Section: Introductionmentioning

confidence: 99%

Repeatability and Agreement of Central Corneal Thickness and Keratometry Measurements between Four Different Devices

Kiraly¹,

Stange

Kunert

et al. 2017

Journal of Ophthalmology

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“…The reported incidence of PLE is low, varying between 0.04% and 0.6% depending on the population being studied 2,3. Given the large number of LASIK procedures performed each year, even a low incidence of PLE is significant and warrants efforts to reduce its occurrence and also to improve on current available treatments.…”

Section: Discussionmentioning

confidence: 93%

Under-flap stromal bed CXL for early post-LASIK ectasia: a novel treatment technique

Wallerstein¹,

Adiguzel²,

Gauvin³

et al. 2016

OPTH

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PurposeCollagen cross-linking (CXL) for post-laser-assisted in situ keratomileusis (LASIK) ectasia (PLE) is traditionally performed either epi-on or epi-off on the corneal surface. This study describes a novel technique in treating early PLE with under-flap CXL (ufCXL) to the stromal bed and reports on 6-month outcomes.Patients and methodsCase series of seven patients (eight eyes) with topography-diagnosed early PLE treated with ufCXL. Inclusion criteria were early, mild PLE defined as new-onset postoperative manifest refraction cylinder ≤1.50 D, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity (UDVA) of 20/40 or better, and corrected distance visual acuity (CDVA) of 20/25 or better. Existing LASIK flap was lifted, riboflavin was applied directly to the stromal bed, flap was repositioned, and 18 mW/cm2 ultraviolet light was applied for 3 minutes to the corneal surface. Post-ufCXL manifest refraction, UDVA and CDVA, corneal cylinder, Kmax, and corneal irregularity index were compared with pre-ufCXL measurements.ResultsPatients had a pre-ufCXL sphere of 0.09±0.48 D and cylinder of −0.78±0.49 D. At 6 months, post-ufCXL sphere (0.06±0.8 D; P=0.89) and cylinder (−1.09±0.76 D, P=0.26) were unchanged. Cumulative post-ufCXL UDVA was unchanged, achieving 20/20, 20/30, and 20/40 in 25%, 88%, and 88%, respectively, compared with 13%, 63%, and 88% pre-ufCXL (P=0.68). Post-ufCXL CDVA was unchanged (P=0.93) with a gain of one line in two eyes, a loss of one line in one eye, and five eyes unchanged. The efficacy index (P=0.76), safety index (P=0.89), Kmax (P=0.94), and corneal irregularity index (P=0.73) were also unchanged.ConclusionPreliminary results with ufCXL for early PLE are promising, demonstrating maintenance of visual accuracy, efficacy, safety, Kmax, and cylinder, with much quicker recovery times than surface CXL.

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“…The other risk factors included low residual stromal bed thickness, age of the patient and preoperative corneal thickness. Santhiago et al . recommended that preoperative screening before refractive surgery should include analysis of intrinsic biomechanical properties (data obtained from corneal topography/tomography and patient’s age) and the analysis of alterable biochemical properties (data obtained from the amount of tissue altered by surgery and the remaining load‐bearing tissue).…”

Section: Clinical Applications Of Corneal Topographymentioning

confidence: 99%

Applications of corneal topography and tomography: a review

Fan

Chan

Prakash³

et al. 2018

Clinical Exper Ophthalmology

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Corneal imaging is essential for diagnosing and management of a wide variety of ocular diseases. Corneal topography is used to characterize the shape of the cornea, specifically, the anterior surface of the cornea. Most corneal topographical systems are based on Placido disc that analyse rings that are reflected off the corneal surface. The posterior corneal surface cannot be characterized using Placido disc technology. Imaging of the posterior corneal surface is useful for diagnosis of corneal ectasia. Unlike corneal topographers, tomographers generate a three-dimensional recreation of the anterior segment and provide information about the corneal thickness. Scheimpflug imaging is one of the most commonly used techniques for corneal tomography. The cross-sectional images generated by a rotating Scheimpflug camera are used to locate the anterior and posterior corneal surfaces. The clinical uses of corneal topography include, diagnosis of corneal ectasia, assessment of corneal astigmatism, and refractive surgery planning. This review will discuss the applications of corneal topography and tomography in clinical practice.

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Ectasia risk factors in refractive surgery

Cited by 114 publications

References 66 publications

Repeatability and Agreement of Central Corneal Thickness and Keratometry Measurements between Four Different Devices

Repeatability and Agreement of Central Corneal Thickness and Keratometry Measurements between Four Different Devices

Under-flap stromal bed CXL for early post-LASIK ectasia: a novel treatment technique

Applications of corneal topography and tomography: a review

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