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Objetivo: Determinar parámetros aberrométricos de la córnea para la detección del queratocono subclínico. Métodos: Se realizó un estudio observacional, analítico de corte transversal que incluyó 36 pacientes con queratocono subclínico (grupo de estudio) y 36 estudiantes con córneas aparentemente sanas (grupo control), que asistieron a la consulta de córnea del Instituto Cubano de Oftalmología Ramón Pando Ferrer, entre mayo de 2018 y junio de 2022. Se analizaron topografía y aberrometría corneal con el tomógrafo corneal Pentacam AXL. Resultados: El grupo queratocono subclínico mostró valores similares para la queratometría, asfericidad corneal, paquimetría y el valor total de desviación en comparación con el grupo normal. Hubo diferencias estadísticamente significativas en los parámetros aberrométricos, como el coma a 90º (Z3 -1), y la raíz cuadrada media de las aberraciones de alto orden, de cara anterior, posterior y total corneal, en queratocono subclínico en comparación con el grupo normal. El coma posterior a 90º presentó un área bajo la curva (0,894) mayor dentro de las aberrometrías, con un punto de corte de -0,013 μm, con sensibilidad del 86,1 % y especificidad del 88,9 %. Conclusiones: El coma posterior a 90º (parámetro aberrométrico) presenta una alta sensibilidad y especificidad para el diagnóstico de queratocono subclínico, mediante el análisis tomográfico Pentacam AXL.
Objective: To determine corneal aberrometric parameters for the detection of subclinical keratoconus. Methods: An observational, analytical, cross-sectional study was performed including 36 patients with subclinical keratoconus (study group) and 36 students with apparently healthy corneas (control group), who attended the cornea consultation at the Cuban Institute of Ophthalmology Ramón Pando Ferrer, between May 2018 and June 2022. Corneal topography and aberrometry were analyzed with the Pentacam AXL corneal tomographer. Results: The subclinical keratoconus group showed similar values for keratometry, corneal asphericity, pachymetry and total deviation value compared to the normal group. There were statistically significant differences in aberrometric parameters, such as coma at 90° (Z3-1), and root mean square of high-order anterior, posterior and total corneal aberrations in subclinical keratoconus compared to the normal group. The 90° posterior coma presented a higher area under the curve (0.894) within the aberrometries, with a cutoff point of -0.013 μm, with sensitivity of 86.1 % and specificity of 88.9 %. Conclusions: Coma posterior to 90º (aberrometric parameter) presents high sensitivity and specificity for the diagnosis of subclinical keratoconus, using Pentacam AXL tomographic analysis.
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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 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 compare the anterior chamber volume and corneal volume using Pentacam in people with early keratoconus, subclinical keratoconus, and healthy subjects.<p>METHODS: This epidemiologic study was performed on 63 patients who were candidates for refractive surgery. We classified our patients into three groups as normal, subclinical keratoconus, and early keratoconus according to the Amsler-Krumeich criteria. We collected demographic information, including age and sex, and obtained a full medical history of the patients. Complete visual examination was performed for all patients. Then, using Pentacam, corneal volume and anterior chamber volume were measured among three groups. <p>RESULTS: Corneal volume in the control group was significantly higher than the subclinical keratoconus and early keratoconus groups(<i>P</i><0.05), but the anterior chamber volume was not significantly different between the groups(<i>P</i>>0.05).<p>CONCLUSION: Measuring the corneal volume can help to distinguish the eyes with subclinical keratoconus and early keratoconus from normal eyes. The chamber volume might not differ remarkably among people with subclinical keratoconus, early keratoconus, and those with normal eyes.