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Keratoconus (KC) is an irreversible blinding eye disease; therefore, early screening of KC suspects (KCS) is crucial for protecting patients' quality of life. Scheimpflug imaging is a commonly used screening device in clinical practice. We aimed to evaluate the diagnostic ability of a Scheimpflug imaging device (Scansys) for KC and KCS and compared it with other Scheimpflug-based devices (Pentacam and Corvis ST). This prospective case-control study included 107 normal eyes, 72 KCS, and 57 KC. Scansys screening index Keratoconus probability (KCP) showed excellent performance in diagnosing KC at a cutoff value of 16.4 (area under the receiver operating characteristic [AUROC] = 1.000), with 100% sensitivity and 98.11% specificity. KCP had a better KCS diagnostic ability at a cutoff value of 8.9 (AUROC = 0.813) than Corvis biomechanical index (CBI, AUROC = 0.764), reaching 67.61% sensitivity and 85.85% specificity. Pentacam screening index Belin/Ambrósio enhanced ectasia display deviation (BAD-D) showed the best performance with 92.96% sensitivity and 89.62% specificity at a cutoff value of 1.525 (AUROC = 0.970) in diagnosing KCS. Scansys provides accurate KCP parameters in diagnosing KC; however, the efficiency of diagnosing KCS should be further optimized. [ABSTRACT FROM AUTHOR]

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Purpose: Osteogenesis imperfecta (OI) is a rare inherited disease affecting collagen-rich tissues. Ocular complications have been reported such as thin corneas, low ocular rigidity, keratoconus, among others. The purpose of this study is to characterize corneal tomographic features in OI patients compared to unaffected patients, with particular focus on commonly studied keratoconus indices. Methods: Cross-sectional case–control study including 37 OI patients and 37 age-matched controls. Patients and controls underwent comprehensive ophthalmological examination including corneal Scheimpflug tomography with a Pentacam HR device (Oculus Optikgeräte GmbH, Wetzlar, Germany) to analyse and compare topometric, tomographic, pachymetric and Belin-Ambrósio Enhanced Ectasia Display III (BAD-D) data of both eyes of each patient. Results: Most OI patients had type I disease (n = 24; 65%) but type III–VII patients were also included. Two patients had clinically overt bilateral keratoconus. OI patients had significantly higher maximum keratometry (45.2 ± 2.1 vs. 43.7 ± 1.2; p = 0.0416), front and back elevation (3.0 ± 3.3 vs. 2.1 ± 1.3, p = 0.0201; 11.1 ± 8.2 vs. 5.0 ± 3.7, p < 0.0001), index of surface variance (25.5 ± 13 vs. 17.4 ± 8.3; p = 0.0016), index of vertical asymmetry (0.21 ± 0.14 vs. 0.15 ± 0.06; p = 0.0215), index of height asymmetry (9.2 ± 14 vs. 6.0 ± 4.5; p = 0.0421), index of height decentration (0.02 ± 0.01 vs. 0.01 ± 0.01; p < 0.0001) and average pachymetric progression (1.01 ± 0.19 vs. 0.88 ± 0.14; p < 0.0001) readings. Thinnest corneal thickness and maximum Ambrósio relational thickness were significantly lower (477 ± 52 vs. 543 ± 26; 387 ± 95 vs. 509 ± 49; p < 0.0001). Two-thirds of OI patients had corneas with a minimum thickness < 500 µm. BAD-D value was significantly higher in OI patients (2.1 ± 1.4 vs. 0.9 ± 0.2; p < 0.0001). Conclusion: OI patients showed significant changes in corneal profiles compared with healthy subjects. A high proportion of patients had tomographically suspect corneas when using keratoconus diagnostic indices. Further studies are warranted to assess the true risk of corneal ectasia in OI patients. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the accuracy of different corneal parameters in detecting keratoconus using a dual Scheimpflug/Placido system (Sirius, CSO, Italy). Methods: Sixty-eight eyes of 68 keratoconus patients and 77 eyes of 77 normal subjects were prospectively assessed in a diagnostic test study. The mean differences of the corneal parameters were compared using the independent t-test. The accuracy of curvature, elevation, pachymetry, and aberrometry indices, aqueous depth, and corneal volume in 10 mm was evaluated using the area under the curve (AUC), and the DeLong method was used for the comparison of AUCs. Multiple tests in a parallel manner and multiple logistic regression analysis were applied to determine the best predictor indices. Results: All indices except aqueous depth and corneal volume were significantly different between the two groups (P < 0.001). Back keratoconus vertex (KVb) and front Baiocchi–Calossi–Versaci index (BCVf) had the highest sensitivity (for both 98.53%) followed by front symmetry index (SIf) (96.12%) and thinnest point of the cornea (88.24%) in elevation, aberrometry, curvature, and pachymetry parameters, respectively. The highest diagnostic ability was observed in KVb (AUC 0.993) and BCVf index (AUC 0.992) (DeLong > 0.05). Multiple test analysis showed a combination of indices with the highest accuracy that was similar to the performance of each one individually, and keratoconus was diagnosed correctly in 98.5% of the cases (R2 = 93%). Conclusion: The parameters extracted from Sirius can differentiate keratoconus from normal corneas with high accuracy without the need for complex computational algorithms. Elevation-based and combined aberrometry indices had the highest diagnostic power. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the long-term visual, refractive, tomographic, and aberrometric outcomes of corneal collagen crosslinking (CXL) with or without hypoosmolar riboflavin solution in the treatment of progressive keratoconus patients with thin corneas. Methods: Charts of consecutive progressive keratoconus patients with thinnest corneal thickness less than 470 µm who underwent corneal collagen CXL with or without hypoosmolar riboflavin solution and using a standardized protocol for treatment and examinations were analyzed retrospectively. The indication for hypoosmolar riboflavin use was a central corneal thickness less than 400 µm as measured by ultrasound pachymetry after epithelial debridement and before exposure to ultraviolet A (UVA) light. Uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (CDVA), manifest refraction, slit lamp biomicroscopy, corneal tomography, corneal aberrometry, and endothelial cell counts were evaluated at baseline and yearly at all postoperative follow-up examinations until month 36. The outcomes of corneal CXL procedure performed using hypoosmolar riboflavin were compared to those performed using the standard procedure. Results: Twenty-three eyes (19 patients) were treated using hypoosmolar riboflavin application, and 30 eyes (28 patients) were treated using the standard procedure. Compared to baseline, the mean UDVA, CDVA, and keratometric readings improved statistically significantly in both groups at postoperative year 3, without any statistically significant between-group differences. Progression was not observed in any patient eye in either group. No significant endothelial cell loss and no sight threating complication were observed in any patient eye. Conclusion: At 3 years follow-up, the safety and efficacy of CXL using hypoosmolar riboflavin solution seems to be similar to that of standard CXL in progressive keratoconic eyes with thin corneas. The visual, refractive, keratometric, tomographic and aberrometric outcomes of the two procedures were comparable, as well. [ABSTRACT FROM AUTHOR]

Purpose: To analyze refractive and topographic changes secondary to Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes with Fuchs' endothelial dystrophy (FED). Methods: Eighty-seven pseudophakic eyes of 74 patients who underwent subsequent DMEK surgery for corneal endothelial decompensation and associated visual impairment were included. Median post-operative follow-up time was 12 months (range: 3–26 months). Main outcome measures were pre- and post-operative manifest refraction, anterior and posterior corneal astigmatism, simulated keratometry (CASimK) and Q value obtained by Scheimpflug imaging. Secondary outcome measures included corrected distance visual acuity (CDVA), central corneal densitometry, central corneal thickness, corneal volume (CV), anterior chamber volume (ACV) and anterior chamber depth (ACD). Results: After DMEK surgery, mean pre-operative spherical equivalent (± SD) changed from + 0.04 ± 1.73 D to + 0.37 ± 1.30 D post-operatively (p = 0.06). CDVA, proportion of emmetropic eyes, ACV and ACD increased significantly during follow-up. There was also a significant decrease in posterior corneal astigmatism, central corneal densitometry, central corneal thickness and corneal volume over time (p = 0.001). Only anterior corneal astigmatism and simulated keratometry (CASimK) remained fairly stable after DMEK. Conclusion: Despite tendencies toward a hyperopic shift, changes in SE were not significant and refraction remained overall stable in pseudophakic patients undergoing DMEK for FED. Analysis of corneal parameters by Scheimpflug imaging mainly revealed changes in posterior corneal astigmatism pointing out the relevance of posterior corneal profile changes during edema resolution after DMEK. [ABSTRACT FROM AUTHOR]

Purpose: To characterize tomographic patterns and quantify corneal higher-order aberrations (HOAs) in eyes with corneal scar due to phlyctenular keratitis. Study design: Retrospective consecutive case series. Methods: This study included 51 eyes of 38 patients (24 women; 14 men) with corneal scar due to phlyctenular keratitis. HOAs of the total cornea, and of the anterior and posterior surfaces were measured using anterior segment optical coherence tomography (AS-OCT). Corneal tomographic patterns were classified into five types: increased regular astigmatism, ectasia, asymmetric, flattening and minimal change patterns. The correlation between corneal HOAs and visual acuity was evaluated. Results: Mean months from onset was 50.7 ± 74.7 and mean number of recurrences 2.1 ± 1.1 (1–5). Mean logarithm of the minimal angle of resolution (logMAR) was 0.19 ± 0.31. AS-OCT showed ectasia pattern in 16 eyes (31.4%), asymmetric pattern in 12 eyes (23.5%), increased regular astigmatism pattern in 9 eyes (17.6%), flattening pattern in 3 eyes (5.9%) and minimal change pattern in 11 eyes (21.6%). HOAs of the total cornea were 0.57 ± 0.44 μm and 1.16 ± 0.77 μm within a 4-mm and 6-mm diameter, significantly larger than in normal controls (P < 0.0001). LogMAR visual acuity was significantly correlated with corneal HOAs (4-mm: r = 0.558, P < 0.0001, 6-mm: r = 0.566, P < 0.0001), central corneal thickness (r = − 0.349, P = 0.016), and corneal astigmatism (r = 0.414, P = 0.004), but not with average keratometric value (r = − 0.092, P = 0.537). Conclusions: The most common tomographic pattern was ectasia, followed by a asymmetric pattern in eyes with phlyctenular keratitis. Corneal HOAs were associated with decreased visual acuity in phlyctenular keratitis patients. [ABSTRACT FROM AUTHOR]

Introduction: Keratoconus usually presents during puberty and is considered rare in young children. Methods: Case report with clinical findings and computerized corneal tomography. Results: We report the case of an 8-year-old girl with early bilateral keratoconus who presented with allergic conjunctivitis and persistent eye rubbing. Although our patient did not exhibit steep keratometry, early cones and inferotemporal thinnest corneal thicknesses were detected in both eyes using Scheimpflug imaging (Oculus GmbH Pentacam, Wetzlar, Germany). Belin/Ambrósio total D values were 1.85 on the right and 2.11 on the left. Improvement in best-corrected visual acuity was noted after treatment of allergic eye disease, and corneal tomographic findings remained stable 4 months after initial consult. Conclusion: This is a case of early diagnosed keratoconus in a young patient. Diagnosis of this condition in young children is challenging, as these patients are less likely to report visual complaints, and clinical examination is usually unremarkable. Keratoconus screening should be considered in children with atopy and eye rubbing behavior regardless of age, even in those with no other associated pathology and with negative family history. [ABSTRACT FROM AUTHOR]

Purpose: To assess topographic findings, anterior segment parameters and high-order aberrations (HOAs) by using corneal tomography in children with 2 diopters (dp) or more astigmatism. Methods: Children with 2 dp or more astigmatism (study group) and children with astigmatism less than 1 dp (control group) were recruited. Corneal astigmatism, mean, steep, flat keratometry (K) findings, anterior and posterior K results and anterior segment parameters including anterior chamber depth, kappa distance, horizontal corneal diameter, mean, central, middle, peripheral corneal thicknesses (CT), white-to-white (WTW) distance and pupil diameter were measured by Galilei G4 Dual Scheimpflug corneal tomography. HOAs were also assessed and compared between groups. Results: Fifty-eight eyes of 37 children in the study group and 37 eyes of 37 children in the control group were enrolled. The mean ages of groups were 9.7 ± 2.4 years and 9.3 ± 1.6 years in study and control groups, respectively. The mean astigmatism was 3.3 ± 1.1 dp and 0.5 ± 0.3 dp in study and control groups, respectively (p < 0.05). Total corneal astigmatism was 3.3 ± 0.84 dp and 1.14 ± 0.47 dp in study and control groups, respectively (p < 0.05). There was a significant difference between groups in terms of posterior steep K and posterior astigmatism values. Among anterior segment parameters, mean CT and WTW values were statistically different between groups. HOAs were found to be statistically different between groups. Conclusion: Higher posterior corneal astigmatism, thinner mean CT and lower WTW distance were found in children with 2 dp or more astigmatism. Besides, HOAs were much more in these astigmatic children. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate changes in refractive error and corneal tomographic measurements after 24-h monitoring of intraocular pressure patterns with a contact lens sensor (CLS). Study design: Prospective, longitudinal, observational study. Patients and methods: Fourteen eyes of 14 consecutive patients who underwent 24-h CLS monitoring were enrolled. The objective spherical equivalent (SE) refractive error was measured using automated refraction and keratometry. The axial power, instantaneous power, and corneal thickness at the central, paracentral, midperipheral, and peripheral cornea were measured with swept-source anterior-segment optical coherence tomography. Measurements were performed at baseline, immediately after monitoring, and at follow-up visits 2–4 days after monitoring. Results: The myopic SE increased significantly (P < 0.001) from − 5.1 ± 4.2 to − 6.0 ± 4.0, D after 24-h monitoring with a CLS and returned to the premonitoring level at the second visit (− 5.3 ± 4.4 D, P = 0.315). Decreases in the midperipheral and peripheral axial powers and the paracentral instantaneous power and increases in the central instantaneous power and peripheral corneal thickness occurred after CLS monitoring. Conclusion: Twenty-four-hour monitoring with a CLS resulted in significant increases in the myopic refractive error and corneal central steepening and midperipheral flattening. Although these changes are transient and do not negate the clinical merits of the CLS, clinicians should be aware of these potential adverse events. Three-dimensional evaluation of corneal deformation with anterior segment optical coherence tomography is a powerful tool for assessing and improving the safety, tolerability, and accuracy of CLS devices. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of topical prostaglandin (PG) eyedrops on the biomechanics and shape of the cornea. Methods: Consecutive patients with primary open-angle glaucoma who had been treated with the same anti-glaucoma PG (114 eyes, 57 patients) or β-blocker (36 eyes, 18 patients) eyedrops in 1 eye alone for more than 3 months at Inouye Eye Hospital or Miyata Eye Hospital. The biomechanical properties of the cornea were measured using a Corvis ST device (Oculus, Wetzlar, Germany). Corneal tomography was measured with a Casia 1 or 2 (Tomey Corp., Nagoya, Japan). The biomechanical parameters and tomographic features of the cornea were compared between PG-treated eyes, β-blocker-treated eyes, and contralateral eyes using a mixed-effect model adjusted for intraocular pressure and corneal thickness and a linear model adjusted for age, sex, intraocular pressure, and corneal thickness. Results: The PG-treated eyes had a significantly smaller applanation 1 time, the highest concavity radius, and a larger deformation amplitude than the contralateral eyes. Also, the PG-treated eyes had a significantly smaller applanation 1 time and applanation 2 velocity but a larger peak distance than the β-blocker-treated eyes. There were no significant differences in any of the Casia parameters between the PG-treated eyes and the contralateral eyes. Conclusion: The results of this study suggest that topical PG makes biochemical changes to the cornea but does not alter its shape. [ABSTRACT FROM AUTHOR]