Analysis of Corneal Astigmatism before Surgery in Chinese Congenital Ectopia Lentis Patients

Longitudinal changes of refractive error in preschool children with congenital ectopia lentis

BACKGROUND

Congenital ectopia lentis (CEL) is a hereditary eye disease which severely impacts preschool children's visual function and development. This study aimed to evaluate the longitudinal changes in spherical equivalent (SE) refractive error in preschool children with CEL.

METHODS

A retrospective cohort study was conducted at Zhongshan Ophthalmic Center, Guangzhou, China. Medical records of CEL patients under 6-year-old who were diagnosed with Marfan syndrome at the initial visit from January 2014 to March 2022 were collected and were divided into surgery and non-surgery groups. Mean change rate of SE in the two groups was evaluated, and the potential associated factors of SE change rate were investigated by mixed-effect regression model.

RESULTS

A total of 94 preschool patients from 14 provinces of China were included. Among the 42 children of the surgery group, the mean age with standard deviation (SD) was 5.02 ± 0.81 years and patients experienced a myopic shift of -0.05 ± 0.09 D/month in average. The mean age with SD of the 52 children of the non-surgery group was 4.34 ± 1.02 years, and the mean myopic shift was -0.09 ± 0.14 D/month. The mixed-effect regression model identified that higher degree of myopia at baseline was associated with slower myopic shift both in surgery (β = 0.901, 95% CI: 0.822 ~ 0.980, P < 0.001) and in non-surgery group (β = 1.006, 95% CI: 0.977 ~ 1.034, P < 0.001) in CEL patients. Surgical treatment (β = 2.635, 95% CI: 1.376 ~ 3.894, P < 0.001) was associated with slower myopic shift in all participants CEL patients.

CONCLUSIONS

Myopic progression was slower in the surgery group than in the non-surgery group of CEL. Preschool CEL patients who met the surgical indication are suggested being performed with timely surgery to slow down the myopic progression.

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.

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.

Correlation between FBN1 mutations and ocular features with ectopia lentis in the setting of Marfan syndrome and related fibrillinopathies

Mutations of fibrillin-1 (FBN1) have been associated with Marfan syndrome and pleiotropic connective tissue disorders, collectively termed as "type I fibrillinopathy". However, few genotype-phenotype correlations are known in the ocular system. Patients with congenital ectopia lentis (EL) received panel-based next-generation sequencing, complemented with multiplex ligation-dependent probe amplification. In a total of 125 probands, the ocular phenotypes were compared for different types of FBN1 mutations. Premature termination codons were associated with less severe EL and a thinner central corneal thickness (CCT) than the inframe mutations. The eyes of patients with mutations in the C-terminal region had a higher incidence of posterior staphyloma than those in the middle and N-terminal regions. Mutations in the TGF-β-regulating sequence had larger horizontal corneal diameters (white-to-white [WTW]), higher incidence of posterior staphyloma, but less severe EL than those with mutations in other regions. Mutations in the neonatal region were associated with thinner CCT. Longer axial length (AL) was associated with mutations in the C-terminal region or TGF-β regulating sequence after adjusting for age, EL severity, and corneal curvature radius. FBN1 genotype-phenotype correlations were established for some ocular features, including EL severity, AL, WTW, CCT, and so forth, providing novel perspectives and directions for further mechanistic studies.

Characteristics of Corneal Higher-Order Aberrations in Congenital Ectopia Lentis Patients

Purpose

The purpose of this study was to investigate the characteristics of corneal higher-order aberrations (HOAs) in patients with congenital ectopia lentis (CEL).

Methods

Clinical characteristics and HOAs of 60 patients with CEL and 75 healthy controls at Zhongshan Ophthalmic Center in China were retrospectively analyzed. The Q value and the corneal HOAs in the CEL group and the controls were measured by using Pentacam and compared value between the CEL and control groups. The correlation between HOAs and age was investigated using the Pearson correlation analysis.

Results

The Q value of anterior corneal surface in the CEL group was larger than that in the controls (−0.41 ± 0.17 vs. −0.32 ± 0.13, P = 0.001); the total corneal horizontal coma in the CEL group were larger than that in the controls (0.24 ± 0.18 vs. −0.05 ± 0.14, P < 0.001); both the primary spherical aberrations of the anterior and total corneal surface were lower in the CEL group than that in the controls (for anterior corneal surface: 0.15 ± 0.08 vs. 0.27 ± 0.08 µm, P < 0.001; for total corneal surface: 0.10 ± 0.09 vs. 0.23 ± 0.09 µm, P < 0.001), the anterior and total corneal horizontal coma were negatively associated with age, whereas the anterior and total corneal spherical aberrations were positively associated with age in patients with CEL.

Conclusions

Patients with CEL had higher corneal horizontal coma and lower corneal vertical coma primary spherical aberrations than healthy controls.

Translational Relevance

These findings are informative for the clinical managements in patients with CEL.

CRISPR/Cas9 in zebrafish: An attractive model for FBN1 genetic defects in humans

Background

Mutations in the fibrillin‐1 gene (FBN1) are associated with various heritable connective tissue disorders (HCTD). The most studied HCTD is Marfan syndrome. Ninety percent of Marfan syndrome is caused by mutations in the FBN1 gene. The zebrafish share high genetic similarity to humans, representing an ideal model for genetic research of human diseases. This study aimed to generate and characterize fbn1^+/− mutant zebrafish using the CRISPR/Cas9 gene‐editing technology.

Methods

CRISPR/Cas9 was applied to generate an fbn1 frameshift mutation (fbn1^+/−) in zebrafish. F1 fbn1^+/− heterozygotes were crossed with transgenic fluorescent zebrafish to obtain F2 fbn1^+/− zebrafish. Morphological abnormalities were assessed in F2 fbn1^+/− zebrafish by comparing with the Tuebingen (TU) wild‐type controls at different development stages.

Results

We successfully generated a transgenic line of fbn1^+/− zebrafish. Compared with TU wild‐type zebrafish, F2 fbn1^+/− zebrafish exhibited noticeably decreased pigmentation, increased lengths, slender body shape, and abnormal cardiac blood flow from atrium to ventricle.

Conclusion

We generated the first fbn1^+/− zebrafish model using CRISPR/Cas9 gene‐editing approach to mimic FBN1 genetic defects in humans, providing an attractive model of Marfan syndrome and a method to determine the pathogenicity of gene mutation sites.

A scoping review presenting a wide variety of research on paediatric and adolescent patients with Marfan syndrome

Aim

The present study aimed to map and summarise the research on children, aged 0‐18 years, with Marfan syndrome, identify research gaps and point to research agendas.

Methods

A scoping review was systematically performed by searching multiple databases from January 1996 to April 2019. Primary studies presenting results on at least six individuals aged 0‐18 years with Marfan syndrome, diagnosed according to the Ghent nosology, were selected.

Results

From 2341 de‐duplicated records, 92 papers were included, mapped and described. Their topics were diagnostics (12%), cardiovascular matters (50%), skeletal matters (22%), ocular matters (9%), other medical aspects (5%) and psychosocial perspectives (2%). Most studies were from Europe and North America and published between 1999 and 2019 in subject‐specific or paediatric journals, while a few were published in genetics journals. All studies had quantitative designs, and very few were multicentre studies. Each study had six to 608 subjects for a total of approximately 5809.

Conclusion

A wide range of research topics on adolescent and paediatric Marfan syndrome was found, but qualitative studies and a focus on psychosocial matters were lacking. Future investigations addressing noncardiovascular consequences and patient experiences are needed, as well as studies reaffirming or replicating existing intervention study results.