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AIM: To investigate the diagnostic value of ocular morphological parameters under different corneal diameters for early keratoconus.METHODS: A retrospective case-control study. A total of 201 patients(201 eyes)who were treated in our hospital from January 2019 to March 2022 were included. They were divided into 135 cases(135 eyes)in the control group(patients with history of refractive error)and 66 cases(66 eyes)in the subclinical keratoconus group. The Pentacam anterior segment analyzer was used to determine the horizontal central curvature of corneal posterior surface(Kf), posterior vertical central curvature of corneal posterior surface(Ks), average curvature of corneal posterior surface(Km), Posterior I-S ratio, corneal posterior surface height after the thinnest point(PE at the thinnest point), maximum posterior elevation from best fit sphere(MPE from BFS), maximum posterior elevation from best fit toric ellipsoid(MPE from BFTE), posterior asphericity asymmetry index(AAI), thinnest point thickness of the cornea(TCT), central corneal thickness(CCT), depressed corneal thickness(DCT), pachymetric progression index average(PPIavg), Ambrósio relational thickness maximum(ARTmax)and Belin D value. The differences of each parameter between the two groups were analyzed. Receiver operating characteristic(ROC)curves were analyzed to determine the best diagnosis point. The control group was further divided into groups according to the corneal diameter: corneal diameter ≤11.0mm, 11.1mm≤ corneal diameter ≤11.5mm, 11.6mm≤ corneal diameter ≤12.0mm, corneal diameter ≥12.1mm. The differences of each parameter among these groups were compared. Pearson correlation analysis was used to analyze the correlation between corneal diameter and other parameters.RESULTS: There were significant differences in posterior I-S ratio, PE at the thinnest point, MPE from BFS, MPE from BFTE, posterior AAI, TCT, DCT, PPIavg, ARTmax, Belin D value between the subclinical keratoconus group and the control group(P<0.05). Sensitive index of Pentacam to diagnosis subclinical keratoconus were Belin D value, posterior I-S ratio, PPIavg, posterior AAI and MPE from BFTE(AUC≥0.9). In the control group, there was no significant difference in posterior I-S ratio, MPE from BFTE, posterior AAI, TCT, CCT, and DCT among different corneal diameter groups (P>0.05), and there was no significant correlation with corneal diameter(all P>0.05).CONCLUSION: The Belin D value, posterior I-S ratio, PPIavg, posterior AAI, MPE from BFTE obtained by Pentacam are sensitive indicators for the diagnosis of early keratoconus, among which posterior I-S ratio, posterior AAI, MPE from BFTE are less affected by corneal diameter. They play an important role in the early diagnosis of keratoconus under different corneal diameters.
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@#AIM:To study the relationship between astigmatism and keratoconus by using Pentacam anterior segment analyzer.METHODS:Totally 88 patients(93 eyes)with early keratoconus were divided into clinical keratoconus group(43 cases, 46 eyes)and subclinical keratoconus group(45 cases, 47 eyes)according to related standards. Meanwhile, 40 patients(41 eyes)with history of myopia and astigmatism(astigmatism ≥2.0D)were recorded as the control group. The keratoconus index(KI), corneal index of surface variance(ISV)and index of vertical asymmetry(IVA)were determined using Pentacam anterior segment analyzer, and their diagnostic value for keratoconus was analyzed.RESULTS:The parameters of Pentacam anterior segment analyzer were different among the three groups(<i>P</i><0.05). Rmin was the highest, and other parameters were the lowest in the control group. Rmin was lower, and other parameters were higher in the clinical keratoconus group than in the subclinical keratoconus group(<i>P</i><0.05). The area under curve(AUC)values of ISV, KI, IVA, index of highest decentration(IHD), aberration coefficient(ABR), corneal anterior surface maximum keratometry(Kmax), posterior corneal surface elevation(PE), minimun radius of curvature(Rmin)and corneal anterior surface elevation(AE)in the diagnosis of clinical keratoconus were 1, 1, 1, 1, 0.950, 0.919, 0.951, 1 and 0.992, with good sensitivity and specificity. IVA, Rmin, AE, and PE had better sensitivity and specificity in the diagnosis of subclinical keratoconus. The AUC values were 0.927, 0.923, 0.954, and 0.947, respectively.CONCLUSION:Pentacam anterior segment analysis system has great value in early diagnosis of keratoconus.
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Objective:To investigate the stability of anterior chamber following implantable collamer lens (ICL) V4c implantation for one year in moderate and high myopic eyes.Methods:An observational case series study was conducted.Medical data of 19 patients (37 eyes) who received ICL V4c implantation in Xuzhou First People's Hospital from March 2016 to October 2017 were collected.The patients were 20 to 29 years old, with the preoperative spherical equivalent (SE) of -5.875 to -15.750 D, with an average of (-9.743±3.220)D.All eyes were followed up for one year, and the changes of visual acuity, SE and intraocular pressure were observed.Pentacam anterior eye segment analyzer was used to measure the anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA) before operation and at 1 month, 6 months and 1 year after operation, and to evaluate the vaults of the ICL V4c at different time points after implantation.This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Xuzhou First People's Hospital (No.xxy11[2015]-XJS-004). Written informed consent was obtained from each subject.Results:There were statistically significant differences in visual acuity between before and after operation ( F=5.057, P=0.007), and the one-year postoperative uncorrected visual acuity (UCVA) was significantly better than the best corrected visual acuity (BCVA) before operation ( P<0.05). There were no significant differences in SE and intraocular pressure among different time points ( F=1.294, 1.302; both at P>0.05). There were significant differences in ACD, ACV and ACA among different time points ( F=44.811, 889.971, 196.096; all at P<0.001). ACD, ACV and ACA at 1 month, 6 months and 1 year after operation were significantly lower than those before operation (all at P<0.001). There was a significant difference in the 1-month, 6-month and 1-year postoperative ICL vault ( F=7.256, P=0.001). The ICL vault at 1 year after operation was (433.784±168.550)μm, which was significantly decreased in comparison with (484.860±183.634)μm at 1 month and (464.351±170.167)μm at 6 months after operation ( P=0.006, 0.041). Conclusions:The anterior chamber is stable in one year after ICL V4c implantation, and the UCVA is better than preoperative BCVA.ICL V4c is safe and effective for moderate and high myopia.
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@#AIM: To analyze the diagnostic value of Pentacam anterior segment analyzer examination parameters on early keratoconus.<p>METHODS: Retrospective control study. Totally 100 patients(124 eyes)with keratoconus who were treated in the hospital between January 2019 and January 2020 were selected as study group. According to the severity of Amsler-Krumeich classification, patients with keratoconus were divided into mild group(51 eyes), moderate group(43 eyes)and severe group(30 eyes), and another 30 normal people with past history of myopia and astigmatism(30 eyes)were selected as control group. The Pentacam anterior segment analyzer parameters \〖horizontal central curvature of 3mm diameter range(K1), vertical central curvature of 3mm diameter range(K2), maximum refractive power of corneal anterior surface(Kmax), corneal astigmatism(Cyl), corneal thickness at the thinnest(thinnest local), ROC curve was used to analyze the sensitive indicators in the diagnosis of early keratoconus.<p>RESULTS:The K1, K2, Kmax, Cyl, ISV, IVA, KI and ACD in study group were significantly higher than those in control group(<i>P</i><0.05)while the thinnest local and ACV were significantly lower than those in control group(<i>P</i><0.05). There were statistically significant differences in the K1, K2, Kmax, Cyl, thinnest local, ISV, IVA, KI, ACV and ACD among patients with different degrees of keratoconus(<i>P</i><0.05), and the K1, K2, Kmax, Cyl, ISV, IVA, KI and ACD in moderate group and severe group were significantly higher than those in mild group(<i>P</i><0.05)while the thinnest local and ACV were significantly lower than those in mild group(<i>P</i><0.05), and there were significant differences in the parameters between moderate group and severe group(<i>P</i><0.05). ROC diagnostic curve results showed that Kmax, thinnest local, ISV, IVA and KI were sensitive indicators for diagnosing keratoconus(AUC>0.85), of which ISV had the highest diagnostic value.<p>CONCLUSION: Pentacam anterior segment analyzer can effectively measure the keratoconus parameters. There are differences in the parameters among patients with different degrees of keratoconus. Kmax, thinnest local, ISV, IVA and KI are sensitive indicators for diagnosing early keratoconus, and Pentacam anterior segment analyzer examination parameters have a higher diagnostic value on early keratoconus.
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@#AIM: To explore the clinical application of Pentacam anterior segment analyzer in early keratoconus diagnosis.<p>METHODS: Selected 49 patients(49 eyes)with early keratoconus who were treated in our hospital from February 2019 to December 2019.According to the Rabinowitz diagnostic criteria, they were divided into 27 cases(27 eyes)in the clinical keratoconus group and 22 cases(22 eyes)in the subclinical keratoconus group. Another 20 cases(20 eyes)of normal eyes with myopia and astigmatism were selected as the control group. The Pentacam anterior segment analyzer was used to determine the index of surface variance(ISV), keratoconus index(KI), index of vertical asymmetry(IVA), central keratoconus index(CKI), index of highest decentration(IHD), index of highest asymmetry(IHA), aberration coefficient, minimum sagittal curvature(Rmin), corneal astigmatism(CYL), corneal anterior surface height(AE), maximum refractive power of the cornea and corneal posterior surface height(PE). Compare the detection values of the three groups of indicators, and draw the ROC curve, and analyze the clinical value of various indicators in diagnosing keratoconus.<p>RESULTS: The three groups of ISV, KI, IVA, CKI, IHD, IHA, ABR, Rmin, CYL, AE, Kmax and PE detection values were significantly different(<i>P</i><0.05). Compared with the control group, the ISV, KI, IVA, CKI, IHD, IHA, ABR, Rmin, CYL, AE, Kmax and PE detection value in the clinical keratoconus group were statistically significant(<i>P</i><0.05). Compared with the control group, the ISV, KI, IVA, CKI, IHD, IHA, ABR, Rmin, CYL, AE, Kmax and PE detection value in the clinical keratoconus group were statistic significant(<i>P</i><0.05). The results of ROC curve analysis showed that the sensitivity and specificity of keratoconus in the clinical phase of IVA, KI, AE, PE, Rmin, IHD, Kmax, ISV and ABR were higher. IVA, Rmin, AE and PE diagnosis of subclinical keratoconus sensitivity and specificity were higher.<p>CONCLUSION: The Pentacam anterior segment analyzer accurately measures the morphological parameters of the anterior and posterior surface of the cornea, which plays an important role in the early clinical diagnosis of keratoconus.
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@#AIM: To evaluate the difference and consistency of pupillary offset measured by the Pentacam anterior segment analyzer and Keratron Scout corneal topographer.<p>METHODS: Three hundred and eleven patients(604 eyes)who underwent excimer laser in situ keratomileusis from November 2017 to February 2018 were randomly selected. Before surgery, the pupillary offset values were measured by Pentacam and Keratron, and the differences and consistency of the values between the two instruments were compared.<p>RESULTS: The pupillary offset values of the right eyes, left eyes, and both eyes between Pentacam and Keratron were statistically different(<i>P</i><0.05). There were no significant statistical differences in the offset orientations of right eyes, left eyes and both eyes between the two instruments(<i>P</i>>0.05). The 95% consistent line(<i>LoA</i>)of offset value and offset orientation in the right eyes, left eyes and both eyes between the two instruments were -0.11-0.19mm and -157.01°-135.35°, -0.12-0.18mm and -150.16°-158.22°, -0.11-0.19mm and -154.30°-147.10°, respectively. <p>CONCLUSION: The pupillary offset measured by the Pentacam was smaller than that measured by the Keratron, but the difference was within the clinically acceptable range. The accurate pupillary offset can be obtained, and be the mutual reference, correction and supplement in the both instruments.