Corneal Curvature, Astigmatism, and Aberrations in Marfan Syndrome with Lens Subluxation: Evaluation by Pentacam HR System

Genotype-phenotype Correlations of Ocular Posterior Segment Abnormalities in Marfan Syndrome

Purpose

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 ( (FBN1). In addition to typical phenotypes such as ectopia lentis (EL) and aortic dilation, patients with MFS are prone to ocular posterior segment abnormalities, including retinal detachment (RD), maculopathy, and posterior staphyloma (PS). This study aims to investigate the correlations between FBN1 genotype and posterior segment abnormalities within a Chinese cohort of MFS.

Design

Retrospective study.

Participants

One hundred twenty-one eyes of 121 patients with confirmed FBN1 mutations between January 2015 and May 2023 were included.

Methods

Comprehensive ophthalmic examination findings were reviewed, and the incidence of RD, atrophic, tractional, and neovascular maculopathy (ATN classification system), and PS was analyzed between different genotype groups. Only the more severely affected eye from each patient was included.

Main Outcome Measures

Clinical features and risk factors.

Results

Of 121 patients, 60 eyes (49.59%) exhibited posterior segment abnormalities, including RD (4, 3.31%), maculopathy (47, 38.84%), and PS (54, 44.63%). The mean age was 11.53 ± 11.66 years, with 79.34% of patients <20 years old. The location and region of mutations were found to be associated with the incidence of maculopathy (P = 0.013, P = 0.033) and PS (P = 0.043, P = 0.036). Mutations in the middle region had a lower incidence of maculopathy and PS (P = 0.028 and P = 0.006, respectively) than those in C-terminal region. Mutations in the transforming growth factor-β (TGF-β) regulating sequence exhibited a higher incidence of maculopathy and PS (P = 0.020, P = 0.040). Importantly, the location and region of mutations were also associated with the incidence of atrophic maculopathy (P = 0.013 and P = 0.033, respectively). Mutations in the middle region had a significantly lower probability of atrophic maculopathy (P = 0.006), while mutations in the TGF-β regulating region had a higher incidence of atrophic maculopathy (P = 0.020).

Conclusions

Maculopathy and PS were associated with the location and region of FBN1 mutations. Patients with mutations in the TGF-β regulating region faced an increased risk of developing retinopathy.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Visual Outcomes in Ectopia Lentis in Marfan Syndrome: A Study of Four Surgical Techniques in Children and Adults

Background/Objectives: To evaluate how the surgical technique and type of implanted intraocular lens influence the postoperative visual acuity and complications in ectopia lentis associated to Marfan syndrome patients. Materials and Methods: The medical records and videos of ectopia lentis surgeries in patients (children and adults) with Marfan syndrome, were retrospectively reviewed and compared. The study included 33 eyes that underwent four different intraocular lens implantation (IOL) techniques: IOL in conjunction with a simple capsular tension ring, IOL in conjunction with a Cionni modified capsular tension ring (m-CTR), two-point scleral IOL fixation and IOL with one haptic in the bag and one haptic sutured to the sclera. Results: Vision significantly improved from a mean preoperative visual acuity of 0.1122 to a mean postoperative visual acuity of 0.4539 in both age groups (p < 0.0001), with no difference in the primary outcome between children and adults. The most common surgical technique used in both age groups was IOL in conjunction with an m-CTR. There was only one major postoperative complication requiring additional surgery. Conclusions: Zonular weakness mainly influenced by age was the most important selection criterion for the surgical approach. Regardless of the technique employed, the postoperative visual acuity was improved in both adults and children.

Application of sutureless corneal incision for patients with congenital ectopia lentis - Is it feasible, effective and safe?

Purpose: To compare the clinical outcomes, feasibility, and safety between groups with sutured and sutureless wound closure in congenital ectopia lentis (CEL) patients. Methods: Patients with CEL who received phacoemulsification combined with intrascleral fixation of capsular hook (CH) and implantation of capsular tension ring (CTR) and in-the-bag intraocular lens (IOL) were included in this study. Results: A total of 68 eyes of 34 patients aged 18 years or younger were enrolled in this study. Incisions of 21 patients (34 eyes) did not require sutures while sutures were applied in 21 patients (34 eyes). Postoperative uncorrected distance visual acuity, best corrected distance visual acuity and intraocular pressure measurements were comparable on follow-up visits (P > 0.05). The magnitude of surgically induced astigmatism was significantly greater (P = 0.001) in the suture group (Median: 0.47; IQ: 1.63, 2.97) than in the sutureless group (Median: 0.88; IQ: 0.63, 1.35). No cases of endophthalmitis and retinal detachment were found postoperatively in either group, while suture-related complications were observed in the sutured group, including loose suture with discomfort in 5 (14.71%) eyes, loose suture with mucus infiltration in 3 (8.82%) eyes. In total, 22 sutures (64.71%) of 34 eyes required removal. Conclusions: Sutureless clear corneal incision in CEL patients can achieve satisfactory clinical results comparable to sutured wound closure in terms of the efficacy and safety. Advantages of this approach are the reduced risk of suture-related complications, no need for additional surgery under general anesthesia for suture removal, and less cost.

Biometric and corneal characteristics in marfan syndrome with ectopia lentis

PURPOSE

To describe the biometric and corneal characteristics of patients with Marfan Syndrome (MFS) and ectopia lentis.

STUDY DESIGN

Observational, descriptive, prospective study. Subjects Individuals with MFS with ectopia lentis (EL).

METHODS

Fourty-four eyes of 23 patients underwent Scheimpflug analysis using the Pentacam (Oculus, Wetzlar, Germany), axial length (AL) using the IOL master 700 (Carl Zeiss AG, Oberkochen, Germany), endothelial cell count (ECC) using the CEM-350 (NIDEK, Maihama, Japan) and corneal biomechanics evaluation with the Ocular Response Analyzer: ORA (Reichert Ophthalmic Instruments, Buffalo, New York, USA) and Corvis (Oculus, Wetzlar, Germany). Statistical analysis was performed using IBM SPSS Statistics 25.0.

RESULTS

The direction of lens subluxation was most frequently supero-nasal 40.9% (18/44). Mean keratometry (Km) was 40.22±1.76 Diopters (D); mean corneal astigmatism was 1.68±0.83 D; total corneal aberrometric root mean square (RMS) was 2.237±0.795μm; higher-order aberrations (HOAs) RMS were 0.576±0.272μm; mean AL was 25.63±3.65mm; mean ECC was 3315±459cell/mm2; mean CBI was 0.13±0.24, mean TBI was 0.31±0.25, mean posterior elevation was 4.3±4.5μm; mean total corneal densitometry was 16.0±2.14 grayscale units (GSU).

CONCLUSION

Increased axial length, flatter and thicker corneas with higher regular astigmatism, normal densitometry, normal corneal biomechanical indices and normal posterior elevation were observed in Marfan patients with EL.

Genetic Correlations Among Corneal Biophysical Parameters and Anthropometric Traits

Purpose

The genetic architecture of corneal dysfunction remains poorly understood. Epidemiological and clinical evidence suggests a relationship between corneal structural features and anthropometric measures. We used global and local genetic similarity analysis to identify genomic features that may underlie structural corneal dysfunction.

Methods

We assembled genome-wide association study summary statistics for corneal features (central corneal thickness, corneal hysteresis [CH], corneal resistance factor [CRF], and the 3 mm index of keratometry) and anthropometric traits (body mass index, weight, and height) in Europeans. We calculated global genetic correlations (rg) between traits using linkage disequilibrium (LD) score regression and local genetic covariance using ρ-HESS, which partitions the genome and performs regression with LD regions. Finally, we identified genes located within regions of significant genetic covariance and analyzed patterns of tissue expression and pathway enrichment.

Results

Global LD score regression revealed significant negative correlations between height and both CH (rg = -0.12; P = 2.0 × 10-7) and CRF (rg = -0.11; P = 6.9 × 10-7). Local analysis revealed 68 genomic regions exhibiting significant local genetic covariance between CRF and height, containing 2874 unique genes. Pathway analysis of genes in regions with significant local rg revealed enrichment among signaling pathways with known keratoconus associations, including cadherin and Wnt signaling, as well as enrichment of genes modulated by copper and zinc ions.

Conclusions

Corneal biophysical parameters and height share a common genomic architecture, which may facilitate identification of disease-associated genes and therapies for corneal ectasias.

Translational Relevance

Local genetic covariance analysis enables the identification of associated genes and therapeutic targets for corneal ectatic disease.

Comparison of Accuracy in Keratometries Measured by Different Camera Devices for Predicting the Intraocular Lens Power in Lens-Dislocated Patients

INTRODUCTION

This is a cross-sectional cohort study focused on assessing the influence of ocular biometric parameters of different camera devices for accurately predicting the intraocular lens (IOL) power in congenital ectopia lentis (EL) patients.

METHODS

This study includes a total of 91 eyes of 60 patients with congenital EL from June 2018 to April 2021. All patients underwent lens subluxation surgery with Cionni modified capsular tension rings implantation. Ocular parameters measured by partial coherence interferometry (IOLMaster 700; Carl Zeiss Meditec AG, Jena, Germany) and rotating Scheimpflug camera (Pentacam HR system; Oculus Optikgeräte GmbH, Wetzlar, Germany) were acquired from the database. The authenticity of the different keratometries (Ks) was analyzed by comparing the prediction error in spherical equivalent under controlled formula SRK/T, Haigis, and after Wang-Koch (WK) adjustment.

RESULTS

We observed significant greater K values were obtained in IOLMaster than Pentacam, resulting in more significant hyperopia error while calculating SRK/T. The IOL power calculated with the total corneal refractive power (TCRP) from Pentacam revealed the highest prediction accuracy, indicating that TCRP is the closest to the actual refractive power of the cornea. However, in an exceptional case for long eye patients, total K from IOLMaster was better recommended when using formula Haigis with WK adjustment.

CONCLUSIONS

For most instances, TCRP is the best-recommended source of K value while calculating IOL power for EL patients. However, the total K from IOLMaster preferably fits for long eye patients, who require WK adjustment for Haigis formula.

Cysteine Substitution and Calcium-Binding Mutations in FBN1 cbEGF-Like Domains Are Associated With Severe Ocular Involvement in Patients With Congenital Ectopia Lentis

Purpose: To investigate the clinical manifestations of congenital ectopia lentis (CEL) in patients with fibrillin (FBN1) calcium-binding epidermal growth factor (cbEGF)-like mutations.

Design: Retrospective cohort study.

Methods: Consecutive 68 CEL probands with FBN1 cbEGF-like mutations were recruited, mostly comprising Marfan syndrome (MFS) patients. Patients were classified into the cysteine group (n = 43), calcium (Ca²⁺)-binding group (n = 13) or the others (n = 12) according to their genotypes. Ocular biometrics, morbidities and visual performance were compared among different mutation groups. Linear regression was used to evaluate the risk factors for axial length (AL) elongation.

Results: With age-adjustment, cysteine substitution and Ca²⁺-binding mutations positively contributed to AL elongation (standardized coefficient: 0.410 and 0.367, p = 0.008 and 0.017, respectively). In addition, cataract formation was more frequently detected in patients with Ca²⁺-binding mutations (observed n = 3, expected n = 1.0; p = 0.036). Patients with cysteine substitutions had the poorest preoperative visual acuity among the three groups (p = 0.012) and did not recover as well as other patients. More MFS diagnoses were made in patients with cysteine substitutions (observed n = 16, expected n = 12.6), while ectopia lentis syndrome was detected more often in patients with cbEGF-like mutations out of the functional regions (observed n = 6, expected n = 2.5; p = 0.023).

Conclusion: Compared with patients with cbEGF-like mutations out of functional regions, patients with cysteine substitutions or Ca²⁺-binding mutations had longer ALs with age adjustment, poorer ocular involvement, visual performance, and systematic manifestations.

Analysis of Corneal Spherical Aberrations in Chinese Bilateral Ectopia Lentis Patients

Purpose: To analyze the anterior, posterior, and total corneal spherical aberrations (ASA, PSA, and TSA) in patients with Chinese bilateral ectopia lentis (EL).

Methods: A cross-sectional study was conducted to evaluate corneal spherical aberration (CSA) using a Pentacam system at the 6-mm optical zone. Axial length, keratometry, astigmatism, and corneal asphericity were also determined.

Results: This study included 247 patients (420 eyes) with a mean age of 18.1 years. The values of ASA, PSA, and TSA were 0.136 ± 0.100 μm, −0.118 ± 0.030 μm, and 0.095 ± 0.095 μm, respectively. In the EL patients with Marfan syndrome (MFS), ASA and TSA were significantly lower than in the non-MFS patients (0.126 ± 0.094 μm vs. 0.155 ± 0.107 μm, P = 0.004 for ASA; 0.085 ± 0.091 μm vs. 0.114 ± 0.099 μm, P = 0.003 for TSA), whereas PSA was not significantly different (P = 0.061). The values of ASA and TSA were significantly higher in the patients with EL aged ≥ 40 years old than in younger patients, whereas ASA and PSA were lower in patients aged <10 years old than in older patients (all P < 0.05). In the multiple linear regression analysis, age, keratometry, astigmatism, anterior asphericity, higher-order aberration (HOA), and lower-order aberration (LOA) were positively or negatively correlated with TSA in the patients with EL (r = 0.681, P < 0.001).

Conclusions: Corneal spherical aberration was low in the patients with EL especially for MFS and tended to increase with aging. Preoperatively, individual measurement of CSA was necessary for bilateral EL patients with MFS.

Accuracy of IOL power calculation formulas in Marfan lens subluxation patients with in-the-bag IOLs and implantation of scleral-sutured single-eyelet modified capsular tension rings

PURPOSE

To investigate the accuracy of intraocular lens (IOL) formulas for the prediction of postoperative refraction in lens subluxation in Marfan syndrome.

SETTING

Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Consecutive retrospective clinical observational case series.

METHODS

60 eligible eyes with lens subluxation from 39 young patients with Marfan syndrome (8.53 ± 4.38 years) underwent phacoemulsification combined with single-eyelet modified capsular tension ring (MCTR) and IOL implantation. The prediction error values with mean zero out (relative prediction error) and their absolute values (AE) were calculated.

RESULTS

Generally, the SRK/T formula with Wang-Koch (WK) adjustment had the lowest median AE at 0.418 diopters (D), and the Holladay 1 with WK adjustment had the lowest mean AE at 0.499 D. The median AE of the other 10 formulas, in order from lowest to highest, were Haigis with WK (0.494 D), Holladay 1 with WK (0.495 D), Hoffer Q with WK (0.508 D), Haigis (0.525 D), T2 (0.542 D), Hoffer Q (0.624 D), SRK/T and Holladay 1 (0.660 D), Super (0.680 D), and Barrett Universal II (0.714 D) formulas. Haigis formula was found to be statistically significantly different from SRK/T, Holladay 1, and Barrett Universal II (all 3 P < .001) but not Hoffer Q (P = .236) formula.

CONCLUSIONS

The Haigis formula was recommended for young Marfan lens subluxation patients with in-the-bag IOLs and scleral-sutured single-eyelet MCTR implantation. WK adjustments were successful in those cases where the axial length was longer than 25.0 mm.

Evaluation of axial length/total corneal refractive power ratio as a potential marker for ocular diagnosis of Marfan's syndrome in children

AIM

To investigate whether the axial length (AL)/total corneal refractive power (TCRP) ratio is a sensitive and simple factor that can be used for the early diagnosis of Marfan's syndrome (MFS) in children.

METHODS

The relationship between the AL/TCRP ratio and the diagnosis of MFS for 192 eyes in 97 children were evaluate. The biological characteristics, including age, sex, AL, and TCRP, were collected from medical records. Receiver operating characteristic (ROC) curve analysis was performed to investigate whether the AL/TCRP ratio effectively distinguishes MFS from other subjects. The Youden index was used to re-divide the whole population into two groups according to an AL/TCRP ratio of 0.59.

RESULTS

Of 96 subjects (mean age 7.46±3.28y) evaluated, 56 (110 eyes) had a definite diagnosis of MFS in childhood based on the revised Ghent criteria, 41 (82 eyes) with diagnosis of congenital ectopia lentis (EL) were included as a control group. AL was negatively correlated with TCRP, with a linear regression coefficient of -0.36 (R ²=0.08). A significant correlation was found between age and the AL/TCRP ratio (P=0.023). ROC curve analysis showed that the AL/TCRP ratio distinguished MFS from the other patients at a threshold of 0.59. MFS patients were present in 24/58 (41.38%) patients with an AL/TCRP ratio of ≤0.59 and in 34/39 (87.18%) patients with an AL/TCRP ratio of >0.59.

CONCLUSION

An AL/TCRP ratio of >0.59 is significantly associated with the risk of MFS. The AL/TCRP ratio should be measured as a promising marker for the prognosis of children MFS. Changes in the AL/TCRP ratio should be monitored over time.

Clinical Ocular Diagnostic Model of Marfan Syndrome in Patients With Congenital Ectopia Lentis by Pentacam AXL System

Purpose

To construct an ocular diagnostic model of Marfan syndrome (MFS) distinguishing MFS from congenital ectopia lentis by the Pentacam AXL system.

Methods

Multivariable logistic regression was performed for the MFS ocular model. Furthermore, discrimination and calibration were validated externally. Data for 96 patients with ectopia lentis were assigned to the training cohort. Eighty patients with ectopia lentis were assigned to the test cohort. Diagnosis of MFS was based on the Ghent-2 criteria and diagnosis of congenital ectopia lentis in the control did not comply with the Ghent-2 criteria.

Results

The clinical model was based on the axial length/total corneal refractive power ratio. In the training cohort, the area under the receiver operating characteristic curve was 0.816 (95% confidence interval, 0.754-0.878) in the final model, which showed better performance than the previous minor criteria for diagnosis MFS of myopia of more than 3 diopters. In the test cohort, the area under the receiver operating characteristic curve was 0.818 (95% confidence interval, 0.718-0.918). In decision curve analysis, the net benefit of the model was better between threshold probabilities of 40% to 80%.

Conclusions

We demonstrated the value of the axial length/total corneal refractive power ratio as a potential diagnostic marker of MFS and clinical performance of diagnostic models, which may assist ophthalmologists in rapid identification of the patients at high risk of MFS.

Translational Relevance

This clinical ocular diagnostic model can be easily applied using the Pentacam AXL system. This model aids in the early differential diagnosis of MFS from other forms of congenital ectopia lentis, which may decrease the risk of developing severe ocular symptoms.

The role of environment in the pathogenesis of keratoconus

PURPOSE OF REVIEW

This study was conducted to demonstrate the importance of the environment in keratoconus (KC) genesis.

RECENT FINDINGS

Genetic-related connective tissue disorders demonstrate the inconsistency of theories regarding KC pathogenesis since no corneal steepening was observed in the majority of these patients. Despite recent advances and decades of research into the genetics of KC, the identification of disease-causing KC genes has been frustrating. Variants found based on genome-wide and next-generation sequencing only seem to account for a small number of cases or play a limited role in KC pathogenesis.

SUMMARY

The literature shows that mechanical manipulation may be the common underlying factor or the indispensable act precipitating the cascade of events leading to permanent corneal deformation. Hence, ophthalmologists have the opportunity to increase patient awareness about eye manipulation repercussions and treatment for ocular surface disorders.

VIDEO ABSTRACT

http://links.lww.com/COOP/A42.

Systemic diseases and the cornea

There is a number of systemic diseases affecting the cornea. These include endocrine disorders (diabetes, Graves' disease, Addison's disease, hyperparathyroidism), infections with viruses (SARS-CoV-2, herpes simplex, varicella zoster, HTLV-1, Epstein-Barr virus) and bacteria (tuberculosis, syphilis and Pseudomonas aeruginosa), autoimmune and inflammatory diseases (rheumatoid arthritis, Sjögren's syndrome, lupus erythematosus, gout, atopic and vernal keratoconjunctivitis, multiple sclerosis, granulomatosis with polyangiitis, sarcoidosis, Cogan's syndrome, immunobullous diseases), corneal deposit disorders (Wilson's disease, cystinosis, Fabry disease, Meretoja's syndrome, mucopolysaccharidosis, hyperlipoproteinemia), and genetic disorders (aniridia, Ehlers-Danlos syndromes, Marfan syndrome). Corneal manifestations often provide an insight to underlying systemic diseases and can act as the first indicator of an undiagnosed systemic condition. Routine eye exams can bring attention to potentially life-threatening illnesses. In this review, we provide a fairly detailed overview of the pathologic changes in the cornea described in various systemic diseases and also discuss underlying molecular mechanisms, as well as current and emerging treatments.

Visual outcomes of lens subluxation surgery with Cionni modified capsular tension rings in Marfan syndrome

Marfan syndrome (MFS) is a hereditary disease with an incidence of 0.3% in the general population. Approximately 60% of MFS patients with FBN1 gene mutation will suffer ectopia lentis (EL) from the age of 3. With the development of EL, severe loss of vision will accrue because of lens tilt and glaucoma. Cionni modified capsular tension rings (MCTR) has been applied in the surgery for EL in MFS patients. To evaluate visual acuity and safety of using MCTR during lens subluxation surgery in MFS patients, 66 MFS patients (110 eyes) were included in our study, with the mean duration of follow-up of 4.7 months (SD 1.76 months). The capsular bags were preserved in 101 eyes (91.81%) with MCTR implantation. There was an overall significant improvement in BCVA at 1-month follow-up which was maintained at 3 months. Multivariable linear regression revealed that older age at first visit was associated with greater postoperative BCVA at the 1-month follow-up (P = 0.007). A significant difference was found between different degrees of lens subluxation and the length of surgical time and complications. At follow-up, only two eyes (1.98%) were identified to have developed retinal detachments. In conclusion, better visual outcomes can be achieved when patients received an early operation with MCTR implantation.

Differential diagnosis of Marfan syndrome based on ocular biologic parameters

Background

The present study aimed to investigate the ocular characteristics of Chinese patients with Marfan syndrome (MFS) and to evaluate the sensitivity and specificity of ocular parameters in distinguishing MFS from ectopia lentis.

Methods

A total of 103 patients (103 eyes) with ectopia lentis from 13 provinces and 47 cities were recruited from Zhongshan Ophthalmic Center, Sun Yat-sen University, from June 2017 to June 2019. Ghent-2 criteria were used, as they are the gold standard diagnostic criteria for MFS. Ocular parameters, such as flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km), corneal astigmatism (AST), axial length (AL), white-to-white corneal diameter (WTW), central corneal thickness (CCT), and axial length/curvature radius (AL/CR), were recorded. Diagnostic analyses based on various combinations of parameters to differentiate MFS from ectopia lentis were made using receiver-operating characteristic (ROC) curves.

Results

The mean age of the 103 included patients was 10.25±9.67 (range: 3–48) years, and 66.02% were male. Km combined with CCT was found to have good sensitivity and specificity in the differential diagnosis of MFS from ectopia lentis; Km of 41.36 D and CCT of 537.32 mm were found to be the optimal cut-off points, representing a sensitivity of 89.8% and specificity of 68.7%.

Conclusions

Special characteristics of ocular parameters were detected in MFS. Our findings indicate that ocular biologic parameters are valuable for the differential diagnosis of MFS from ectopia lentis. Km, combined with CCT, could be used as a screening tool for MFS.

Accommodative tissues influence the shape of the cornea and potentially drive corneal morphogenesis

This study investigates whether the presence of accommodative tissues biomechanically influences the shape of the cornea and potentially drives corneal morphogenesis during embryonic ocular development. Porcine eyes were subjected to an internal pressure simulating intraocular pressure. Ocular geometry was evaluated using a corneal topographer and digital cameras before and after dissection of the accommodative tissues. A computational model of the porcine eye was constructed and loaded by an internal pressure representing intraocular pressure. Eye shape was evaluated in models with and without the ciliary body. The porcine model was generalized to the human model, simplified model, or embryonic model with different ocular tissue shapes, sizes, and stiffnesses. Experimental data showed that, even in the six-month-old pig eye, the average corneal radius of curvature increased after the removal of accommodative tissues compared to sham controls (p = 0.002). Computational results agreed with the experimental data and further suggested that the change in corneal radius is greater when the tissue stiffness is low and the intraocular pressure is high, regardless of the geometry and size of the eye components. Using a combined in vitro and in silico approach, this study explores the biomechanical influence of the accommodative tissues and related loads on the cornea and offers additional factors that might influence the shape of the cornea.