Age Differences in Axial Length, Corneal Curvature, and Corneal Astigmatism in Marfan Syndrome with Ectopia Lentis

Initial screening for occult congenital ectopia lentis based on ocular biological parameters in preschool children

BACKGROUND

This study aimed to identify an initial screening tool for congenital ectopia lentis (CEL) by comparing ocular biological parameters in children with myopia.

METHODS

A retrospective case-control study was conducted at one tertiary referral centre, from October 2020 to June 2022. Axial length (AL), corneal curvature (CC), refractive astigmatism (RA), corneal astigmatism (CA), internal astigmatism (IA), the difference between the axis of RA and CA [AXIS(RA-CA)], white-to-white corneal diameter (WTW), and axial length-corneal radius ratio (AL/CR) were compared in 28 eyes of CEL patients, and 60 eyes of myopic patients matched for age and refraction. The spherical equivalent of each eye was < -3.00 D. Area under the curve (AUC) of the receiver operating characteristic curves were calculated.

RESULTS

The differences in RA, AL, mean keratometry (Kmed), maximum keratometry (Kmax), minimum keratometry (Kmin), CA, IA, AXIS(RA-CA), WTW, and AL/CR between the CEL and myopic groups were statistically significant (p < 0.05; p < 0.001; p < 0.001; p < 0.001; p < 0.001; p < 0.05; p < 0.001; p < 0.001; p < 0.001; p < 0.001, respectively). In logistic regression analysis RA, IA, AXIS(RA-CA), and AL/CR were significantly associated with CEL (p < 0.05). AUCs for RA, IA, AXIS(RA-CA), and AL/CR were 0.694, 0.853, 0.814, and 0.960, respectively. AUCs for AL/CR in SE< -6.00 D subgroup was 0.970, and 0.990 in -6.00 D ≤ SE < -3.00 D group. An AL/CR < 3.024 was the optimal cut-off point differentiating the CEL and control groups (sensitivity, 92.9%; specificity, 88.30%).

CONCLUSIONS

A smaller AL/CR could identify CEL in children with myopia. An AL/CR cut-off value of 3.024 may be the most sensitive and specific parameter for the differential diagnosis of CEL in patients with mild to high myopia.

What Should We Pay More Attention to Marfan Syndrome Expecting Ectopia Lentis: Incidence and Risk Factors of Retinal Manifestations

(1) Background: This paper investigates the incidence and risk factors of retinal manifestations in patients with Marfan syndrome (MFS) in a Chinese cohort. (2) Methods: This is a population-based cross-sectional study. In total, 344 eyes (172 MFS participants) were enrolled, each of whom underwent a detailed ocular examination. B-scan ultrasonography, ultra-wide-angle fundus images and optical coherence tomography images were conducted to assess posterior staphyloma, types of retinal damages and maculopathy. (3) Results: MFS patients have a high proportion (32.5%) of maculopathy, among which atrophy is the most common type (27.6%). Compared with participants without maculopathy, participants with maculopathy had a longer axial length (AL), higher incidence of posterior staphyloma, macular split and retinal detachment (RD) (p < 0.001, p < 0.001, p < 0.001 and p = 0.001). Moreover, the stage of RD has a significant correlation with longer AL and shallower anterior chamber depth (ACD) (p = 0.001 and p = 0.034, respectively). (4) Conclusions: A higher incidence and earlier onset of fundus lesions were found in MFS patients. Yearly systematic examination is recommended for MFS children with fundus manifestation until the cardiovascular and skeletal development is complete.

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.

Accuracy of intraocular lens power calculation formulas for eyes with scleral-sutured intraocular lens in congenital ectopia lentis

Purpose

To compare the accuracy of intraocular lens calculation formulas in eyes with congenital ectopia lentis (CEL) that underwent scleral-fixated intraocular lens (IOL) implantation.

Setting

Zhongshan Ophthalmic Center, Guangzhou, China.

Design

Retrospective, consecutive case-series study.

Methods

A total of 158 eyes from 158 patients diagnosed from December 12, 2017 to November 16, 2020 with congenital ectopia lentis and undergoing a lensectomy and a Rayner 920H or 970C model IOL scleral-fixation were retrospectively reviewed. The prediction errors (PEs) of the spherical equivalent of eight formulas, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Holladay 1, Kane, Hill-Radial Basis Function 3.0 (RBF 3.0) and SRK/T were compared.

Results

For CEL patients with sclera-sutured IOL, all eight formulas yielded myopic PEs without constants optimization. After such optimization, the performance of each formula ranked by median absolute error (MedAE) from lowest to highest in diopter, was SRK/T (0.47), EVO (0.48), Kane (0.52), BUII (0.53), Hoffer Q (0.58), Holladay 1 (0.59), Haigis (0.61), and RBF 3.0 (0.62). The EVO and SRK/T formulas had the highest prediction accuracy concerning the percentage of cases within the +/- 0.50 D range of PE and within +/- 1.00 D range of PE in eyes experienced sclera-sutured IOL surgery, respectively.

Conclusion

All formulas with unoptimized constants produced myopic PEs. After optimization, the SRK/T and EVO formula were the two recommended formulas due to having the lowest MedAE and the highest percentage of PE in the range of +/- 0.50 D for CEL patients with sclera-sutured IOL implantations.

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.