Longitudinal assessment of the progression of severe keratoconus based on corneal topography
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SUBMITTER: Yang X
PROVIDER: S-EPMC11344030 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:Custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT) was used to characterize three-dimensionally (3-D) corneal topography in keratoconus before and after implantation of intracorneal ring segments (ICRS). Previously described acquisition protocols were followed to minimize the impact of the motions of the eye. The collected set of images was corrected from distortions: fan (scanning) and optical (refraction). Custom algorithms were developed for automatic detection and classification of volumes in the anterior segment of the eye, in particular for the detection and classification of the implanted ICRS. Surfaces were automatically detected for quantitative analysis of the corneal elevation maps (fitted by biconicoids and Zernike polynomials) and pachymetry. Automatic tools were developed for the estimation of the 3-D positioning of the ICRS. The pupil center reference was estimated from the segmented iris volume. The developed algorithms are illustrated in a keratoconic eye (grade III) pre- and 30 days post-operatively after implantation of two triangular-section, 0.3-mm thick Ferrara ring segments. Quantitative corneal topographies reveal that the ICRS produced a flattening of the anterior surface, a steepening of the posterior surface, meridional differences in the changes in curvature and asphericity, and increased symmetry of the anterior topography. Optical distortion correction through the ICRS (of a different refractive index from the cornea) allowed accurate pachymetric estimates, which showed increased thickness in the ectatic area as well as in peripheral corneal areas. Automatic tools allowed estimation of the depth of the implanted ICRS ring, as well as its rotation with respect to the pupil plane. Anterior segment sOCT provided with fan and optical distortion correction and analysis tools is an excellent instrument for evaluating and monitoring keratoconic eyes and for the quantification of the changes produced by ICRS treatment.
| S-EPMC3342189 | biostudies-other
Project description:We aimed to predict keratoconus progression and the need for corneal crosslinking (CXL) using deep learning (DL). Two hundred and seventy-four corneal tomography images taken by Pentacam HR® (Oculus, Wetzlar, Germany) of 158 keratoconus patients were examined. All patients were examined two times or more, and divided into two groups; the progression group and the non-progression group. An axial map of the frontal corneal plane, a pachymetry map, and a combination of these two maps at the initial examination were assessed according to the patients' age. Training with a convolutional neural network on these learning data objects was conducted. Ninety eyes showed progression and 184 eyes showed no progression. The axial map, the pachymetry map, and their combination combined with patients' age showed mean AUC values of 0.783, 0.784, and 0.814 (95% confidence interval (0.721-0.845) (0.722-0.846), and (0.755-0.872), respectively), with sensitivities of 87.8%, 77.8%, and 77.8% ((79.2-93.7), (67.8-85.9), and (67.8-85.9)) and specificities of 59.8%, 65.8%, and 69.6% ((52.3-66.9), (58.4-72.6), and (62.4-76.1)), respectively. Using the proposed DL neural network model, keratoconus progression can be predicted on corneal tomography maps combined with patients' age.
| S-EPMC7923054 | biostudies-literature
Project description:Purpose: The study aims to identify genetic variants in five Chinese families with Keratoconus (KC) and describe the characteristics of parental corneal topography. Methods: Fifteen participants, including five probands and ten parents from five Chinese families with KC, were recruited for genetic and clinical analyses. Targeted next-generation sequencing using a custom-designed panel for KC was applied on the probands for variant identification. Sanger sequencing and cosegregation analysis of the suspected pathogenic variants were performed on the family members. The pathogenicities of variants were evaluated according to the American College of Medical Genetics and Genomics guidelines (ACMG). Pentacam 3D anterior segment analysis system was applied for keratectasia detection and the Corvis ST for corneal biomechanics measurement. Fifteen parameters were recorded, including nine keratectasia indicators (BAD-D, TP, Kmax, Df, Db, Dp, Dt, Da, ARTH), six corneal biomechanical indicators (CBI, DA ratio, SP-A1, IR, bIOP, TBI). Results: A total of six novel variants, including five missense variants and one frameshift variant, were detected in the HMX1, SLC4A11, TGFBI, PIKFYVE, and ZEB1 genes in five probands, all of which showed co-segregation of genotype and clinical phenotype and were determined to be pathogenic. The genetic model was autosomal dominant (AD) in four families and autosomal recessive (AR) in 1 family. The analysis of keratectasia and corneal biomechanical indicators of the proband's parents (first-generation relatives) in AD families revealed that there were several abnormal indexes in BAD-D, TP, Kmax, Df, Db, Dp, Dt, Da, CBI, DA ratio, SP-A1, IR, bIOP and TBI test indexes, showing clinical characteristics of incipient KC. Conclusion: Our study shows that variants in HMX1, SLC4A11, TGFBI, PIKFYVE, and ZEB1 were associated with KC. Our study extends the gene spectrum associated with KC, provides novel insights into KC phenotypic assessments, and contributes to early diagnosis for these patients.
| S-EPMC9583916 | biostudies-literature
Project description:AimTo compare corneal demarcation line (DL) depth in both accelerated epithelium-off and trans-epithelium cross linking (CXL) using anterior segment optical coherence tomography (AS-OCT) and its relation to maximum keratometry (Kmax) progression in both techniques.MethodsA prospective comparative interventional study where patients with mild to moderate keratoconus (KC) were classified into two groups: accelerated epithelium-off and trans-epithelium CXL based on corneal pachymetry. Assessment of corneal DL depth was carried out after 3mo by AS-OCT. Kmax readings were evaluated after one year follow up using the Scheimpflug imaging system.ResultsStudy included 74 eyes of 44 patients. Group A underwent epithelium-off CXL (41 eyes), while Group B underwent trans-epithelium CXL (33 eyes). At 3mo follow up, mean corneal DL depth in Group A was 219.9±58.4 µm while in Group B was 127.2±7.8 µm (P<0.05). The mean Kmax changed from 51.9±3.9 to 51.3±4.2 diopters in Group A and from 53.1±4.1 to 53.6±5 diopters in Group B with insignificant difference in Kmax changes in either group (P>0.05). In addition, no significant change in corneal pachymetry was found in both groups (mean change at 1y: 6.4±4.7 and -10.1±2.3 µm in Groups A and B respectively).ConclusionDespite a significantly deeper corneal DL depth created by accelerated epithelium-off CXL technique compared to accelerated trans-epithelium CXL, there is no significant impact on keratoconus progression.
| S-EPMC7270254 | biostudies-literature
Project description:BackgroundKeratoconus is a non-inflammatory, chronic, idiopathic, corneal disease characterized by thinning of the core or paracentral part of the cornea. In this study, we demonstrate the prevalence of keratoconus among patients seeking refractive surgery using laser vision correction (LVC) at the Department of Ophthalmology, Private Eye Center, Jazan, Saudi Arabia.Materials and methodsA retrospective cross-sectional study was undertaken with the data from January 1, 2019 to December 31, 2019 in the ophthalmology department of Jazan city. This study included 1068 eyes of 534 patients of which 56.8% were men. The mean patient age was 28.5 (SD = 8.3) years. The analyst performed chi-square tests for the report. Prevalence was calculated at a 95% confidence interval at specified times in the year (CI).ResultsThe prevalence of manifest unilateral keratoconus was 3% and that of bilateral keratoconus was 18.72%; on the other hand prevalence rates of suspected unilateral KC was 16.48% and of bilateral KC 9.36%. Significant differences between eyes were noted and recorded.ConclusionThe occurrence and spread of this condition are on the rise in the city of Jazan and on the outskirts.Terminologyeyeball disorder (keratoconus), prevalence, risk factors, treatment of the disorder (vision).
| S-EPMC9289235 | biostudies-literature
Project description:ObjectiveTo assess the performance of convolutional neural networks (CNNs) for automated detection of keratoconus (KC) in standalone Scheimpflug-based dynamic corneal deformation videos.DesignRetrospective cohort study.ParticipantsWe retrospectively analyzed datasets with records of 734 nonconsecutive, refractive surgery candidates, and patients with unilateral or bilateral KC.MethodsWe first developed a video preprocessing pipeline to translate dynamic corneal deformation videos into 3-dimensional pseudoimage representations and then trained a CNN to directly identify KC from pseudoimages. We calculated the model's KC probability score cut-off and evaluated the performance by subjective and objective accuracy metrics using 2 independent datasets.Main outcome measuresArea under the receiver operating characteristics curve (AUC), accuracy, specificity, sensitivity, and KC probability score.ResultsThe model accuracy on the test subset was 0.89 with AUC of 0.94. Based on the external validation dataset, the AUC and accuracy of the CNN model for detecting KC were 0.93 and 0.88, respectively.ConclusionsOur deep learning-based approach was highly sensitive and specific in separating normal from keratoconic eyes using dynamic corneal deformation videos at levels that may prove useful in clinical practice.Financial disclosuresProprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
| S-EPMC10587634 | biostudies-literature
Project description:PurposeTo characterize corneal structural changes in keratoconus using a new morphogeometric approach and to evaluate its potential diagnostic ability.MethodsComparative study including 464 eyes of 464 patients (age, 16 and 72 years) divided into two groups: control group (143 healthy eyes) and keratoconus group (321 keratoconus eyes). Topographic information (Sirius, CSO, Italy) was processed with SolidWorks v2012 and a solid model representing the geometry of each cornea was generated. The following parameters were defined: anterior (Aant) and posterior (Apost) corneal surface areas, area of the cornea within the sagittal plane passing through the Z axis and the apex (Aapexant, Aapexpost) and minimum thickness points (Amctant, Amctpost) of the anterior and posterior corneal surfaces, and average distance from the Z axis to the apex (Dapexant, Dapexpost) and minimum thickness points (Dmctant, Dmctpost) of both corneal surfaces.ResultsSignificant differences among control and keratoconus group were found in Aapexant, Aapexpost, Amctant, Amctpost, Dapexant, Dapexpost (all p<0.001), Apost (p = 0.014), and Dmctpost (p = 0.035). Significant correlations in keratoconus group were found between Aant and Apost (r = 0.836), Amctant and Amctpost (r = 0.983), and Dmctant and Dmctpost (r = 0.954, all p<0.001). A logistic regression analysis revealed that the detection of keratoconus grade I (Amsler Krumeich) was related to Apost, Atot, Aapexant, Amctant, Amctpost, Dapexpost, Dmctant and Dmctpost (Hosmer-Lemeshow: p>0.05, R2 Nagelkerke: 0.926). The overall percentage of cases correctly classified by the model was 97.30%.ConclusionsOur morphogeometric approach based on the analysis of the cornea as a solid is useful for the characterization and detection of keratoconus.
| S-EPMC5590974 | biostudies-literature
Project description:IntroductionThe primary objective of this study was to develop an end-to-end model that can accurately identify corneal endothelial cells and diagnose keratoconus based on corneal endothelial images acquired from a non-contact specular microscope.MethodsThis was a retrospective case-control study performed at the Refractive Surgery Center of West China Hospital. A total of 403 keratoconus eyes (221 patients) and 370 myopic eyes (185 normal controls) were consecutively recruited from January 2021 to September 2022. Specular microscopy was used to image and measure the morphometric parameters of the corneal endothelial cells. A Fully Convolutional Network model with a ResNet50 (FCN_ResNet50) was established to perform the endothelial segmentation. The images were then classified using an ensemble machine learning system consisting of four pre-trained deep learning networks: DenseNet121, ResNet50, Inception_v3, and MobileNet_v2. The performance of the models was evaluated based on different metrics, such as accuracy, intersection over union (IoU), and mean IoU.ResultsWe established a fully end-to-end deep-learning model for the segmentation of endothelial and diagnosis of keratoconus. For endothelial segmentation, the accuracy of the FCN_ResNet50 model achieved near 90% with mean IoU converging to about 80%. The ensemble machine learning system can achieve over 92% accuracy, and > 98% area under curve (AUC) values to diagnose keratoconus with endothelial cell images. In addition, we constructed a diagnostic model based on deep-learning features and developed an associated nomogram which manifested an excellent performance for diagnosis and monitoring the progression of keratoconus.ConclusionsOur research developed an end-to-end model to automatically identify and assess corneal endothelial morphological changes in keratoconus eyes. Moreover, we also constructed a novel nomogram, which can provide valuable information for the diagnosis, monitoring, and management of the disease.
| S-EPMC10640564 | biostudies-literature
Project description:AimTo observe the efficacy of simplified one-step thermokeratoplasty for the treatment of severe acute corneal hydrops in keratoconus.MethodsIn this retrospective, noncomparative clinical study, 10 patients (10 eyes) with acute hydrops in keratoconus were treated with simplified one-step thermokeratoplasty. Pain, changes in the corneal curvature, thickness, and size and morphology of the Descemet membrane breaks were detected before and after surgery. Eight patients were successfully treated using modified deep anterior lamellar keratoplasty (DALK). Graft transparency, visual acuity, and immunological rejection were evaluated for 6 to 12mo.ResultsPain and corneal oedema were promptly alleviated, and the intrastromal ruptures diminished within 3 to 6wk after thermokeratoplasty. At 3 to 6wk after corneal oedema was faded, Descemet membrane breaks and intrastromal ruptures were healed. Two patients did not undergo subsequent corneal transplantation after thermokeratoplasty. Eight patients underwent DALK successfully and safely after thermokeratoplasty, without corneal perforation. Central corneal opacity faded or disappeared within 6mo. The mean best-corrected visual acuity was increased to 20/30 at 12 mo after DALK. No one was observed with any immune rejection.ConclusionOne-step thermokeratoplasty can successfully and efficiently accelerate the absorption of prominent corneal oedema in severe acute hydrops patients. This simple procedure with no complications can be performed in the emergency department by residents. This method can improve the safety of DALK and obtain good postoperative vision. Long-term management of acute corneal hydrops using simplified one-step thermokeratoplasty seems promising.
| S-EPMC8818456 | biostudies-literature
Project description:PurposeTo present the case of a patient that underwent corneal crosslinking for progressive keratoconus and 18 months later revealed clinically significant corneal stromal haze.ObservationsA 20-year-old male presented with progressive visual loss OU for the past few years. His corrected distance visual acuity (CDVA) OD was 20/30 (-2.75 -1.75 @55) and OS 20/30 (-0.50 -1.75@110). Corneal topography revealed keratoconus OU and the patient underwent corneal crosslinking according to the Dresden Protocol. The postoperative regimen included combined tobramycin and dexamethasone qid along with lubrication until epithelium healed and then fluorometholone qid with weekly tapering. At 3 months postoperatively, his topography was stable and his corrected distance visual acuity (CDVA) was 20/25 OU. On slit lamp examination, only clinically insignificant stromal haze was observed. At 18 months postoperatively, the patient reported vision deterioration. On examination his CDVA was 20/25 in right eye, and 20/40 in his left eye. Deep stromal haze was revealed in his central cornea, more dense in his left eye. Corneal topography was stable and the CDVA loss was attributed to the notable deep stromal haze. The patient was treated with dexamethasone qid with biweekly tapering. 18 months after corneal crosslinking, the patient demonstrated clinically significant stromal haze, most prominent OS. He was treated with dexamethasone qid. One month later his CDVA OS gradually improved to 20/25, and stromal haze was still noted but less dense.Conclusions and importanceLate-onset deep corneal haze is a possible complication of corneal crosslinking in keratoconic patients.
| S-EPMC6411486 | biostudies-literature