Marfan's syndrome: a refractive challenge for optometrists

Sah, Raman Prasad; Paudel, Nabin; Shrestha, Jyoti Baba

doi:10.1111/cxo.12026

Cited by 4 publications

(6 citation statements)

References 7 publications

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“…Other reported ocular manifestations of MFS include cataract, glaucoma, and retinal detachment. 14 , 16 , 17 , 50 Cataract has been reported in mouse models of MFS, 35 yet in this study we have not observed opacifications in the lenses of the fbn1 zebrafish mutants. Although the induced mutation in the fbn1 re12 is predicted to lead to a premature stop codon and thus truncated protein, we cannot rule out that the phenotypic differences observed in the fbn1 re12 , that is, the lack of axial elongation and cataract development, might be explained by a (partially) remaining functionality of the truncated protein product.…”

Section: Discussioncontrasting

confidence: 50%

“…Increased axial length will result in myopia, flatter corneas will lead to hyperopia, and ectopia lentis can induce myopia, high astigmatism (in cases of partial lens subluxation), or high hyperopia (in cases of complete lens subluxation). 16 , 17 , 50 , 53 In the fbn1 mutant, we found a strong hyperopic shift in the refractive status of the eye, but no changes in the axial length. The hyperopic shift observed in the fbn1 mutant fish is explained by two factors: (1) in zebrafish, the spherical lens is responsible for the full optical power of the eye (the refractive index of the cornea and water is nearly identical, and thus corneal curvature does not contribute to refraction), and (2) the posterior subluxation of the lens caused the optical field to shift backwards.…”

Section: Discussionmentioning

confidence: 66%

“… 35 , 49 Other ocular manifestations include increased axial length, flattened corneas and hypoplastic iris or ciliary muscle. 16 , 17 , 50 – 52 Myopia is one of the systemic features used in the diagnosis of MFS. However, assessing the refractive state of the eye of patients with MFS might be challenging as refraction depends on various parameters, such as axial length, corneal curvature, and lens optics.…”

Section: Discussionmentioning

confidence: 99%

“… 7 , 8 Mutations in PRSS56 cause nanophthalmos or autosomal-recessive posterior microphthalmos 9 – 13 ; mutations in FBN1 have been linked to Marfan syndrome (MFS) and Weill–Marchesani syndrome, both of which are characterized by high myopia and ectopia lentis. 14 – 17 Furthermore, common genetic variants in these two genes have also been associated with myopia and refractive error in genome-wide association studies studies, 1 , 2 , 18 , 19 that is, an exonic variant in PRSS56 (rs1550094-A, direction hyperopia) and an intronic variant in FBN1 (rs34539187-C, direction myopia). In the current study, we adapted commonly used techniques for the in vivo testing of ocular biometry, refractive error, and intraocular pressure (IOP) for application in zebrafish.…”

Section: Introductionmentioning

confidence: 99%

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Zebrafish: An In Vivo Screening Model to Study Ocular Phenotypes

Quint

Tadema

Crins

et al. 2022

Trans. Vis. Sci. Tech.

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Purpose To establish a set of assays that allow the in vivo screening of candidate genes for ocular diseases in zebrafish, with an emphasis on refractive error. Methods Our pipeline includes the most relevant ocular screening measurements to assess (1) ocular biometry using spectral domain optical coherence tomography, (2) refractive status using an eccentric photorefractor, (3) intraocular pressure by tonometry, and (4) optokinetic response to study visual capability in zebrafish. To validate our pipeline and to demonstrate the potential of zebrafish as a valid animal model, we chose two well-characterized genes with an ocular phenotype ( PRSS56 and FBN1 ) and generated two mutant zebrafish lines ( prss56 and fbn1 ). Mutant fish were assessed at 2, 4, and 6 months after fertilization. Results With the proposed phenotyping pipeline, we showed that ocular biometry, refractive status, intraocular pressure, and visual function can be studied in zebrafish. In the prss56 mutant, the pipeline revealed a dramatic decrease in axial length, mainly owing to a decreased vitreous chamber depth, whereas in the fbn1 mutant, ectopia lentis was the most distinctive ocular phenotype observed. Tonometry in both mutant lines showed an increase in intraocular pressure. Conclusions The proposed pipeline was applied successfully in zebrafish and can be used for future genetic screenings of candidate genes. While validating our pipeline, we found a close resemblance between the ocular manifestations in the zebrafish mutants and patients harboring mutations in PRSS56 and FBN1 . Our results support the validity of our pipeline and highlight the potential of zebrafish as an animal model for in vivo screening of candidate genes for ocular diseases.

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Section: Discussioncontrasting

confidence: 50%

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Zebrafish: An In Vivo Screening Model to Study Ocular Phenotypes

Quint

Tadema

Crins

et al. 2022

Trans. Vis. Sci. Tech.

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“…With significant lens subluxation, clear view through the lens is impossible and aphakic eyeglasses should be prescribed. [19]…”

Section: Introductionmentioning

confidence: 99%

Management strategies of ocular abnormalities in patients with marfan syndrome: Current perspective

Esfandiari

Ansari

Mohammad-Rabei

et al. 2019

J Ophthalmic Vis Res

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Marfan syndrome is an autosomal dominant genetic connective tissue disorder that results from mutations in the fibrillin-1 gene located on chromosome band 15q15–21. Fibrillin, a glycoprotein, is widely expressed throughout the body and contributes to the elasticity and force-bearing capacity of connective tissue. In the eye, fibrillin is a key constituent of the ciliary zonules, which suspend the crystalline lens in place. The zonular defect leads to ectopia lentis, which is a hallmark of Marfan ocular abnormalities and occurs in 60% to 80% of cases. Other less common ocular features of Marfan syndrome are increased axial length, astigmatism, and flat cornea. Visual function in Marfan syndrome could be affected in several ways: ectopia lentis, refractive error, amblyopia, retinal detachment, cataract, and glaucoma. Management of a subluxated lens starts with the correction of refractive error with eyeglasses in mild cases. In more severe cases, especially when the lens bisects the pupil, complete correction of refractive error is impossible without removing the subluxated lens. The best method for visual rehabilitation after lens extraction is still debated. Aphakic Artisan lens implantation at the time of subluxated lens removal results in good visual outcomes with an acceptable safety profile. Studies with longer term follow-up and larger sample populations are needed to evaluate the safety of this procedure in patients with Marfan syndrome.

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