Structural Analysis of the Cornea Using Scanning-Slit Corneal Topography in Eyes Undergoing Excimer Laser Refractive Surgery

Kamiya, Kazutaka; Miyata, Kazunori; Tokunaga, Tadatoshi; Kiuchi, Takahiro; Hiraoka, Takahiro; Oshika, Tetsuro

doi:10.1097/01.ico.0000136673.35530.e3

Cited by 36 publications

(21 citation statements)

References 25 publications

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“…Moreover, the biomechanical properties of the cornea may affect not only the refractive outcomes after keratorefractive surgery such as laser in situ keratomileusis (LASIK), leading to unpredictability for this surgical technique [1][2][3][4][5], but also the measurement of the intraocular pressure (IOP) especially in eyes undergoing LASIK [6][7][8][9]. Thus, it is of clinical importance to assess the biomechanical properties of the cornea, but the methodology for the in vivo assessment of corneal biomechanics has not long been established.…”

Section: Introductionmentioning

confidence: 99%

Factors affecting corneal hysteresis in normal eyes

Kamiya

Hagishima

Fujimura

et al. 2008

Graefes Arch Clin Exp Ophthalmol

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103

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Section: Introductionmentioning

confidence: 99%

Factors affecting corneal hysteresis in normal eyes

Kamiya

Hagishima

Fujimura

et al. 2008

Graefes Arch Clin Exp Ophthalmol

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103

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“…However, the risk of the development of iatrogenic keratectasia, resulting from the biomechanical weakening of the cornea, has been reported especially after laser in situ keratomileusis (LASIK) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] , suggesting that LASIK, which requires not only surgical tissue subtraction but also flap creation, in some cases may impair the biomechanical strength of the cornea. The biomechanical properties of the cornea may affect not only the refractive outcomes after keratorefractive surgery such as LASIK, leading to the unpredictability of this surgical technique [16][17][18][19][20] , but also the measurement of the intraocular pressure especially in eyes undergoing LASIK [21][22][23][24] . In consideration of the presence of delayed-onset keratectasia [3,4,10,14] , it is possible that the postoperative corneal biomechanics might be compromised with time.…”

Section: Introductionmentioning

confidence: 99%

Time Course of Corneal Biomechanical Parameters after Laser in situ Keratomileusis

Kamiya¹,

Shimizu²,

Ohmoto³

2009

Ophthalmic Res

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Purpose: To assess the time course of corneal biomechanics after laser in situ keratomileusis (LASIK). Methods: We examined 36 eyes of 20 consecutive patients undergoing LASIK for low to moderate myopia. We quantitatively assessed the values of corneal biomechanics characterized by corneal hysteresis (CH) and corneal resistance factor (CRF) using an Ocular Response Analyzer™ (Reichert Ophthalmic Instruments) before and 1 week, 1, 3, and 6 months after surgery. We carried out this measurement 3 times, and the average value was used for statistical analysis. Results: The CH was 10.6 ± 1.7 (mean ± SD) mm Hg preoperatively, and 8.6 ± 1.2, 9.0 ± 1.7, 9.0 ± 1.4, and 8.9 ± 1.5 mm Hg 1 week, 1, 3, and 6 months postoperatively, respectively. The CRF was 10.0 ± 1.7 mm Hg preoperatively, and 7.3 ± 1.5, 7.6 ± 2.0, 7.8 ± 1.6, and 7.7 ± 1.6 mm Hg 1 week, 1, 3, and 6 months postoperatively, respectively. The variances of the data were statistically significant (p < 0.001 for both CH and CRF). Multiple comparisons demonstrated significant differences between measurements made before surgery and at all postoperative times (at 1 week and 1, 3, and 6 months; p < 0.001 for CH and CRF, Fisher’s least significant difference test). Conclusions: Over the study period, the largest changes in corneal biomechanical parameters occurred within 1 week after surgery, and these then became nearly stable. No progressive deterioration of the corneal biomechanics was observed at any time during the 6-month follow-up period.

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“…Therefore, reaching stability of refraction after surgery needs more time, and iatrogenic keratoectasia may easily happen in these eyes [13,14,15,16]. Fortunately, in most cases, the biomechanical bowing of the cornea is not a true corneal ectasia [3]. From this point of view, lowering the IOP preoperatively and postoperatively may be an effective way to prevent myopic regression and iatrogenic keratoectasia after LASIK.…”

Section: Discussionmentioning

confidence: 99%

“…Kamiya et al [3] reviewed the time course of the corneal anteroposterior shift after LASIK. It was shown that eyes with thinner corneas and higher degrees of myopia, which require a greater ablation depth, are more predisposed to anterior protrusion of the cornea.…”

Section: Discussionmentioning

confidence: 99%

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Regression-Related Factors before and after Laser in situ Keratomileusis

Qi¹,

Hao²,

Xia³

et al. 2006

Ophthalmologica

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The aim of this study was to evaluate the refractive regression-related factors before and after laser in situ keratomileusis (LASIK) for myopia and give a reasonable way to prevent it. The consecutive patients who underwent LASIK from January to June 2004 were reviewed retrospectively. Thirteen eyes from 8 patients with myopic regression and 60 eyes from 42 patients with no myopic regression within 12 months of follow-up were enrolled. We compared the pre- and postoperative data which were associated with regression in the two groups. The mean preoperative intraocular pressure (IOP) was significantly higher in the regression group than in the nonregression group (p = 0.03). During the period of 12 months, the two groups differed in corneal bowing. In the regression group, both posterior and anterior corneal surfaces were significantly bowing (all p < 0.05). In contrast, in the nonregression group, both posterior and anterior surfaces were relatively stable (all p > 0.05). The higher preoperative IOP and the progressive postoperative biomechanical bowing in the posterior and anterior surfaces of the cornea are two factors related to myopic regression in this study. Lowering the IOP preoperatively and postoperatively may be an effective way to prevent the myopic regression after LASIK.

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Structural Analysis of the Cornea Using Scanning-Slit Corneal Topography in Eyes Undergoing Excimer Laser Refractive Surgery

Cited by 36 publications

References 25 publications

Factors affecting corneal hysteresis in normal eyes

Factors affecting corneal hysteresis in normal eyes

Time Course of Corneal Biomechanical Parameters after Laser in situ Keratomileusis

Regression-Related Factors before and after Laser in situ Keratomileusis

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