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Flint Minett has keratoconus, an eye disease, but desperately wants to win a comic book art contest so that he and his new friend McKell Panganiban will be better accepted at middle school.
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Incorrect sleeping position and eye rubbing in patients with unilateral or highly asymmetric keratoconus: a case-control study
PurposeTo evaluate eye rubbing and sleeping position in patients with Unilateral or Highly Asymmetric Keratoconus (UHAKC).MethodsCase-control study of consecutive UHAKC patients diagnosed at the Rothschild Foundation. Controls were age- and sex-matched, randomly selected refractive surgery clinic patients. Patients self-administered questionnaires regarding their family history of keratoconus, eye rubbing, and sleeping habits. All the eyes underwent a comprehensive ocular examination. Logistic regression was used to analyze univariate and multivariate data to identify risk factors for keratoconus.ResultsThirty-three UHAKC patients and 64 controls were included. Univariate analyses showed that daytime eye rubbing [OR = 172.78], in the morning [OR = 24.3], or in eyes with the steepest keratometry [OR = 21.7] were significantly different between groups. Allergy [OR = 2.94], red eyes in the morning [OR = 6.36], and sleeping on stomach/sides [OR = 14.31] or on the same side as the steepest keratometry [OR = 94.72] were also significantly different. The multivariate model also showed statistical significance for most factors including daytime eye rubbing [OR = 134.96], in the morning [OR = 24.86], in the steepest eye [OR = 27.56], and sleeping on stomach/sides [OR = 65.02] or on the steepest side [OR = 144.02]. A univariate analysis in UHAKC group, comparing the worse and better eye, showed that eye rubbing [OR = 162.14] and sleeping position [OR = 99.74] were significantly (p < 0.001) associated with the worse eye.ConclusionOur data suggests that vigorous eye rubbing and incorrect sleeping position are associated with UHAKC. This is especially true in rubbing the most afflicted eye, and contributory sleep position, including positions placing pressure on the eye with the steepest keratometry.
Journal Article
Accelerated Epithelium-off Corneal Cross-linking With Preservation of a Central Epithelial Island in the Management of Paracentral Progressive Keratoconus: A Comparative Clinical Trial
Purpose
To evaluate the efficacy and safety of accelerated corneal cross-linking (A-CXL) while preserving the epithelium over the central 3 mm of the cornea compared to epithelium removal CXL in cases of paracentral keratoconus.
Methods
In this prospective comparative study, 140 eyes of 77 patients were randomized to receive either A-CXL with preservation of the central 3 mm of corneal epithelium or A-CXL with removal of whole corneal epithelium over a central disk area with a diameter of 9 mm. Patients were observed regularly for 1 year after the procedure. The primary outcome measures were to compare early uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), corneal haze, pain, and discomfort in the first week between the two groups. The secondary outcome measure was keratoconus progression after 12 months of follow-up, measured by the maximum keratometry (Kmax) value.
Results
A significant difference was found between the two groups regarding early postoperative CDVA, corneal haze, pain, and discomfort, with more favorable results in the ACXL with preservation of the central 3 mm of corneal epithelium group. At 12 months of follow-up, a significant improvement in UDVA, CDVA, and Kmax was noticed among patients of the same group, with better final vision and a reduction in Kmax as compared to the preoperative values.
Conclusions
Preserving the epithelium over the central 3 mm of the cornea during A-CXL in cases with paracentral keratoconus can provide the benefits of immediate early postoperative visual rehabilitation, less corneal haze, less pain, good efficacy, and prevention of keratoconus progression.
[J Refract Surg. 2025;41(5):e492–e500.]
Journal Article
Integration of Scheimpflug-Based Corneal Tomography and Biomechanical Assessments for Enhancing Ectasia Detection
To present the Tomographic and Biomechanical Index (TBI), which combines Scheimpflugbased corneal tomography and biomechanics for enhancing ectasia detection.
Patients from different continents were retrospectively studied. The normal group included 1 eye randomly selected from 480 patients with normal corneas and the keratoconus group included 1 eye randomly selected from 204 patients with keratoconus. There were two groups: 72 ectatic eyes with no surgery from 94 patients with very asymmetric ectasia (VAE-E group) and the fellow eyes of these patients with normal topography (VAE-NT group). Pentacam HR and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) parameters were analyzed and combined using different artificial intelligence methods. The accuracies for detecting ectasia of the Belin/Ambrósio Deviation (BAD-D) and Corvis Biomechanical Index (CBI) were compared to the TBI, considering the areas under receiver operating characteristic curves (AUROCs).
The random forest method with leave-one-out cross-validation (RF/LOOCV) provided the best artificial intelligence model. The AUROC for detecting ectasia (keratoconus, VAE-E, and VAE-NT groups) of the TBI was 0.996, which was statistically higher (DeLong et al., P < .001) than the BAD-D (0.956) and CBI (0.936). The TBI cut-off value of 0.79 provided 100% sensitivity for detecting clinical ectasia (keratoconus and VAE-E groups) with 100% specificity. The AUROCs for the TBI, BAD-D, and CBI were 0.985, 0.839, and 0.822 in the VAE-NT group (DeLong et al., P < .001). An optimized TBI cut-off value of 0.29 provided 90.4% sensitivity with 96% specificity in the VAE-NT group.
The TBI generated by the RF/LOOCV provided greater accuracy for detecting ectasia than other techniques. The TBI was sensitive for detecting subclinical (fruste) ectasia among eyes with normal topography in very asymmetric patients. The TBI may also confirm unilateral ectasia, potentially characterizing the inherent ectasia susceptibility of the cornea, which should be the subject of future studies. [J Refract Surg. 2017;33(7):434-443.].
Journal Article
Biomechanical properties analysis of forme fruste keratoconus and subclinical keratoconus
PurposeTo analyze the biomechanical properties of the eye in patients with unilateral keratoconus with normal (forme fruste keratoconus [FFKC]) or abnormal topography (subclinical keratoconus [SKC]).MethodsThis study included 153 eyes of 153 participants, including 95 eyes of patients with unilateral keratoconus, and 58 eyes of 58 healthy controls. Contralateral eyes with unilateral keratoconus were divided into two groups according to clinical manifestations and global consensus: FFKC (n = 30) and SKC (n = 65). The biomechanical characteristics were analyzed using non-parametric tests; further analysis thereof was performed after adjusting for confounding factors (i.e., intraocular pressure, age, and corneal thickness). Receiver operating characteristic curve (ROC) was used to analyze the ability of the biomechanical parameters to distinguish FFKC from SKC.ResultsStatistically significant differences between the FFKC and SKC groups were found in 9 of the 18 corneal biomechanical parameters analyzed using non-parametric tests. After adjusting for confounding factors, the multivariate analysis still revealed significant statistical differences in A1-time (P = 0.017), integrated radius (IR) (P = 0.024), and tomographic and biomechanical index (TBI, P < 0.001) between the FFKC and SKC groups. Stiffness parameter at first applanation (SP-A1) (Area under ROC [AUROC] = 0.765) demonstrated the strongest distinguishing ability, except for TBI (AUROC = 0.858) and Corvis Biomechanical Index (AUROC = 0.849), however, there was no statistically significant difference in SP-A1 (P = 0.366) between FFKC and SKC.ConclusionsBiomechanical parameters A1-time and IR have a high diversity between FFKC and SKC, besides TBI, and may reflect more subtle changes in corneal biomechanical properties (BPs) preceding SP-A1. The BPs of SKC are weaker than FFKC, which might be a basic and clue for the classification and diagnosis of the severity of early keratoconus in terms of biomechanics.
Journal Article
Compression sutures combined with intracameral air injection versus thermokeratoplasty for acute corneal hydrops: a prospective-randomised trial
AimsTo compare the efficacy of compression sutures combined with intracameral air injection (CSAI) and thermokeratoplasty (TKP) for the management of acute corneal hydrops in keratoconus.MethodsIn this multi-centre randomised clinical trial, 20 patients with keratoconus (20 eyes) with acute corneal hydrops were enrolled and randomised to receive either CSAI or TKP and followed-up for a period of 6 months.ResultsThere were no significant differences in patient demographics, severity of corneal hydrops and preoperative duration of symptoms between the two groups. In both groups, corneal oedema resolved within 2 weeks. The maximum thickness of the corneal scars following CSAI and TKP was not significantly different. Best spectacle-corrected visual acuity was superior in the CSAI group at 6-month follow-up (CSAI vs TKP, 0.52 (0.37, 0.85) vs 0.96 (0.70, 1.34) LogMAR, p=0.042). CSAI resulted in greater corneal endothelial cell density (CSAI vs TKP, 2677.8±326.7 vs 1955.3±298.1 cells/mm2, p<0.001) and flatter corneal curvature (CSAI vs TKP: mean keratometry value, 52.13±4.92 vs 63.51±5.83D, p<0.001; maximum keratometry value, 65.21±7.42 vs 77.13±12.01D, p=0.016) at the 6-month follow-up.ConclusionAlthough both CSAI and TKP resulted in resolution of acute corneal hydrops in keratoconus, CSAI was associated with superior clinical outcomes in this study.Chinese Clinical trial registration numberChiCTR-IOR-17013764
Journal Article
Repeatability and comparison of new Corvis ST parameters in normal and keratoconus eyes
To evaluate the repeatability of corneal biomechanical parameters in normal and keratoconus eyes, and explore factors that affects the repeatability, and further assess the diagnostic ability of new parameters. Seventy-seven keratoconus eyes of 47 patients and 77 right eyes of 77 normal subjects were recruited in current study. All participants received three repeated measurements with 2 to 5 minutes interval. The interclass correlation coefficient (ICC), Cronbach’ α and repeatability coefficient (RC) were evaluated. The liner regression analysis was used to identify factors that affect the repeatability, and linear mixed effects model was performed to compare the parameters differences. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic ability of new parameters. Eighteen parameters in normal eyes and twenty-two parameters in keratoconus eyes showed excellent repeatability (ICC ≥ 0.90). Age, axial measurement (AL), spherical equivalent, astigmatism, gender, mean keratometry (Kmean), intraocular pressure (IOP) and central corneal thickness (CCT) could affect the repeatability of new Corvis ST parameters. Compared with normal eyes, the Ambrósio’s Relational Thickness horizontal (ARTh), biomechanical corrected IOP (bIOP), stiffness parameter at first applanation (SP A1) were low and the Max Inverse Radius, deformation amplitude (DA) Ratio Max [2 mm], Pachy Slope, DA Ratio Max [1 mm], Integrated Radius and Corvis Biomechanical Index (CBI) were high in keratoconus eyes (All
P
< 0.05). Both ARTh and CBI had high Youden index (0.870), and the corresponding cut-off values were 379.29 and 0.44. The repeatability of Corvis ST parameters was acceptable both in normal and keratoconus eyes, and new parameters could effectively diagnose keratoconus eyes from normal eyes.
Journal Article
The Genetic and Environmental Factors for Keratoconus
Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.
Journal Article