Imaging interface fluid after laser in situ keratomileusis with corneal optical coherence tomography (original) (raw)
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Journal of Cataract & Refractive Surgery, 2000
Optical coherence tomography (OCT) is an interferometric imaging technique. This study aimed to employ OCT to evaluate four different resin-based materials including a coating containing glass-ionomer filler and calcium, a giomer, and two fluoride-releasing self-etch resins. The coating and its underlying and adjacent enamel were monitored using swept-source OCT (center wavelength: 1330 nm) at baseline, after 5,000 thermal cycles, and after 1, 4 and 7 days of demineralization (pH 4.5). The coatings showed different thicknesses (60-250 micrometers) and various levels of structural and interfacial integrity. OCT could detect a demineralization inhibition zone adjacent to the edge of the fluoride-and calcium-releasing material. Localized demineralization was occasionally observed under thinner coatings. Protection of susceptible enamel surfaces by thin resin-based bioactive coatings provides protection from demineralization. OCT can be used to non-destructively monitor the integrity of such coatings, as well as enamel changes beneath and adjacent to them.
Journal of Cataract & Refractive Surgery, 2009
A 52-year-old man had laser in situ keratomileusis (LASIK) for treatment of a post-keratoplasty refractive error. At the 6-week postoperative visit, haziness was noted in the donor cornea and Snellen visual acuity had decreased to 20/400. Goldmann applanation tonometry revealed an intraocular pressure (IOP) of 2 mm Hg at the center of the cornea but an elevated IOP at the periphery. Visante optical coherence tomography (OCT) and corneal topography were performed, and steroid-induced lamellar keratitis (SILK) was diagnosed. Topical antiglaucoma medications were started, and steroid treatment was switched to fluorometholone. At the last follow-up visit, 2 weeks after treatment was started, the visual acuity was 20/60 and the IOP was controlled at 18 mm Hg centrally and at the periphery. The use of Visante OCT and corneal topography were helpful in diagnosing SILK and monitoring its resolution.
Corneal Densitometry as a Tool to Measure Epithelial Ingrowth After Laser In Situ Keratomileusis
Cornea, 2017
This study evaluates the correlation between corneal densitometry and epithelial ingrowth (EI) after laser in situ keratomileusis (LASIK). Corneal densitometry of 3 patients who developed EI after LASIK was measured with the Oculus Pentacam. Corneal densitometry readings of each patient were obtained preoperatively and postoperatively after ingrowth was discovered. Densitometry was recorded at the central nest of opacity and at the leading edges of EI. For all patients, the most severe stages of EI observed on slit-lamp photographs correlated with the highest densitometry readings, with peak densitometry ranging from 73.3 to 95.1. These values were much higher than preoperative densitometry readings, which ranged from 21.8 to 27.2. In 2 cases, the Pentacam densitometry map revealed progression of EI toward the visual axis that was only faintly detectable or not detectable at all on the corresponding slit-lamp photographs. Corneal densitometry seems to be an objective measure of the ...
Keratocyte density of central human cornea after laser in situ keratomileusis1 1
American Journal of Ophthalmology, 2002
To determine changes in keratocyte density in the first year after laser in situ keratomileusis (LASIK). Prospective interventional cohort study. Seventeen eyes of 11 patients received LASIK with a planned 180-microm flap to correct refractive errors between -2.0 diopters and -11.0 diopters. Images of the full-thickness cornea were obtained by using confocal microscopy in vivo before LASIK and at 1 week, 1, 3, 6, and 12 months after LASIK. Bright objects (that resembled keratocytes) in images without motion blur were manually counted by one observer. Cell densities were determined in anterior and posterior halves of the stromal flap, anterior and posterior halves of the layer 100 microm-thick immediately deep to the ablation (retroablation layer), and in the posterior third of the stroma. The region of stroma that was ablated (as measured 1 month after LASIK) was omitted from the preoperative analysis. Keratocyte density in the anterior flap was 28,978 +/- 5849 cells/mm(3) (mean +/- SD) pre-LASIK, and was decreased at all postoperative examinations, but the difference was not significant until 12 months after LASIK (22% decrease). Keratocyte densities in the posterior flap were 20,397 +/- 4215 cells/mm(3) pre-LASIK and were decreased by 20%-40% at all postoperative examinations 1 week to 1 year after LASIK. Keratocyte densities in the anterior half of the retroablation layer were 16,605 +/- 3595 cells/mm(3) pre-LASIK and decreased by 16%-30% between 3 and 12 months after LASIK. Keratocyte densities in the posterior half of the retroablation layer and posterior stroma did not change. Keratocyte densities in the posterior flap and anterior retroablation layer (regions adjacent to the lamellar cut) decrease at 1 week and 3 months, respectively, after LASIK and remain decreased in these regions at 12 months after LASIK. In the anterior flap, keratocyte density decreases 1 year after LASIK. The long-term effects of these cellular deficits, if any, require further study.
Acute keratoconus-like hydrops after laser in situ keratomileusis
Journal of ophthalmology, 2009
Purpose. To demonstrate keratoconus-like hydrops after laser in situ keratomileusis (LASIK) by optical coherence tomography (OCT). Patient and Methods. A 21-year-old man received uneventful bilateral LASIK. On slit lamp examination or corneal topography there were no signs of fruste keratoconus. The preoperative corneal thickness was 587-mum OD and the calculated ablation for two treatments was 114-mum. Uneventful LASIK with an optical zone of 7 mm and an ablation of 89-mum OD, and an ablation of 73-mum OS was performed. Three years postoperatively, he complained about progressive myopia and impaired vision OD. His VA was hand motion OD and 20/20 OS. Results. OCT and light microscopy revealed an anterior corneal steepening and acute keratoconus-like excessive edematous swelling. Conclusion. The cornea is mechanically weakened after LASIK by the lamellar cut and tissue subtraction. Although the advocated minimal residual stromal bed thickness is 250-mum, it may not be adequate to pre...
2004
To investigate the changes in the epithelium and flap after laser in situ keratomileusis (LASIK), when measured with optical coherence tomography (OCT). METHODS. Twenty-eight eyes of 14 patients (age: 39.9 Ϯ 8.6 years) underwent LASIK. The central thickness of corneal epithelium and flap were measured with a real-time 1310 nm OCT 1 day, 1 week, and 1 month after surgery. A custom software program was used to process multiple images of each eye on each visit. RESULTS. After surgery, the corneal epithelium changed significantly (ANOVA: F (3, 81) ϭ 12.3, P ϭ 0.000) with not statistically significant thinning at one day (mean Ϯ SD: 57.8 Ϯ 5.9 m, P ϭ 0.26, compared with baseline: 59.9 Ϯ 5.9 m) and statistically significant thickening at 1 week (60.8 Ϯ 5.8 m, P ϭ 0.04, compared with 1 day) and 1 month (64.6 Ϯ 6.1 m, P ϭ 0.008 compared with all others). There were statistically significant changes in the corneal flap thickness (ANOVA: F (2, 54) ϭ 4.59, P ϭ 0.01) with thickening in the intervals between 1 day (143.3 Ϯ 20.6 m) and 1 week (149.7 Ϯ 24.6 m, P ϭ 0.12), and between 1 week and 1 month (152.7 Ϯ 19.3 m, P ϭ 0.01). There was a strong correlation (r ϭ 0.898) between the difference of corneal thickness before and after surgery and predicted laser ablation depth. CONCLUSIONS. OCT is a useful noncontact tool for thickness measurements of the epithelium, flap, and total cornea. After LASIK, the epithelium and flap showed thickening during the study period. (Invest Ophthalmol Vis Sci.