|Year : 2022 | Volume
| Issue : 1 | Page : 30-32
Keratoconus in Marfan syndrome: Is it a paradox?
Shivananda Narayana1, Bidisha Mahapatra2, Kunal Mandli1
1 Medical Officer, Cornea and Refractive Services, Aravind Eye Hospital, Pondicherry, India
2 Cornea Fellow, Cornea and Refractive Services, Aravind Eye Hospital, Pondicherry, India
|Date of Submission||16-Mar-2021|
|Date of Acceptance||06-Jul-2021|
|Date of Web Publication||07-Jan-2022|
Dr. Bidisha Mahapatra
Department of Cornea and Refractive Services, Aravind Eye Hospital, Thavalakuppam, Pondicherry- 605 007
Source of Support: None, Conflict of Interest: None
Ocular manifestations of Marfan syndrome (MFS) include features such as ectopia lentis (most common), increased axial length, and flat cornea. Reports of keratoconus in such patients are limited. We report tomographic findings consistent with keratoconus in a patient with MFS. A 15-year-old male presented with gradually progressive decreased vision in both eyes. External physical features being consistent with MFS, on ocular examination, was found to have very high average keratometries bilaterally with tomographic evidence of advanced keratoconus. Although a rare presentation, concurrent MFS and keratoconus should be considered when reviewing the ocular health of MFS patients and appropriate management steps should be taken upon the diagnosis.
Keywords: Flat cornea, keratoconus, Marfan syndrome
|How to cite this article:|
Narayana S, Mahapatra B, Mandli K. Keratoconus in Marfan syndrome: Is it a paradox?. Indian J Ophthalmol Case Rep 2022;2:30-2
Marfan syndrome (MFS) is a genetic disease first described by Antoine Marfan, a French paediatrician in 1896, caused by a mutation in the gene FBN1 that creates abnormalities in a protein called fibrillin-1, an essential component of connective tissue. The changes seen in MFS result from the abnormal collagen synthesis which alters the biomechanics of soft tissues of the human body. MFS affects the skeletal, cardiovascular and ocular systems. The Marfan patient is often very tall with long, flexible extremities and marked scoliosis, exhibit arachnodactyly with the ability to dramatically encircle the wrist (Walker-Murdoch sign). In addition, they often have pectus excavatum, a high-arched palate and other facial abnormalities. The cardiovascular findings range from mild mitral valve prolapse to severe aortic aneurysm or dissection.
A wide spectrum of ocular abnormalities is associated with this disease. Diagnostic criteria were last updated in 2010 (Ghent 2 criteria). In these criteria, ectopia lentis is a cardinal diagnostic feature. Other diagnostic ocular findings are downslanting palpebral fissures, enophthalmos, and myopia >3 diopters (D). Increased axial length (>23.5 mm), a flat cornea (<41.5 D average corneal curvature), iris transillumination defects, and retinal detachment are common in MFS but not part of the Ghent 2 criteria.
Though the pathophysiology of keratoconus is poorly understood, breaks in Bowman's layer, collagen abnormality, and mechanical trauma such as eye rubbing are believed to be contributing but not yet established. Keratoconus has a known association with Downs syndrome, Leber's congenital amaurosis, and connective tissue diseases such as Ehlers's Danlos. However, the association of keratoconus with MFS has rarely been reported in the literature so far.
| Case Report|| |
A 15-year-old boy presented to us with gradual, progressive, and painless decrease in vision in both eyes since past 6 months. General physical examination revealed tall and thin stature with disproportionately long slender extremities, high arched palate with crowded teeth, hyperextensible joints, and arachnodactyly [Figure 1]a, [Figure 1]b, [Figure 1]c. Systemic examination was within normal limits. Best-corrected visual acuity (BCVA) in the right eye was 1/60. The cornea was steep, thinned, scarred with the presence of Fleisher ring and Vogts striae. BCVA in the left eye was 6/24. The cornea was steep, thinned with prominent corneal nerves. Munson sign was positive in both eyes. No obvious phacodonesis was seen in either of the eyes. Intraocular pressure was normal in both eyes. Posterior segment on evaluation was found to be within normal limits. There was no history of chronic eye rubbing.
|Figure 1: (a) Arachnodactyly with hyperflexible joints. (b) High-arched palate with crowded teeth. (c) Arm span greater than the height. (d) The right eye pentacam shows steep mean K reading, stage 4 keratoconus. (e) The left eye pentacam shows steep mean K reading, stage 3–4 keratoconus. (f) The right eye corneal Scheimpflug image. (g) The left eye corneal Scheimpflug image|
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Pentacam (Oculus, Wetzlar, Germany) tomography revealed a mean keratometry of 70.7 D in OD [Figure 1]d and 67.5 D in OS [Figure 1]e. Corneal thickness at the thinnest point was 378 μm in OD and 434 μm in OS. Scheimpflug image of the right eye and the left eye showed features of keratoconus [Figure 1]f, [Figure 1]g.
Average keratometries above 47–48 D have been shown to correlate with keratoconus. Based on the Amsler–Krumeich Classification system, our patient was diagnosed with stage 4 keratoconus. This diagnosis was reinforced with the Pentacam Belin/Ambrosio Enhanced Ectasia Display which highlights tomographic abnormalities consistent with keratoconus.
Since the right eye showed signs of advanced keratoconus with scarring and thinning, hence was planned for deep anterior lamellar keratoplasty, while the left eye underwent collagen cross-linking to arrest the progression of the disease.
| Discussion|| |
Despite the wide variety of ocular manifestations, it is the corneal manifestations that are intriguing and not been accorded sufficient importance in literature. Previous studies have shown that MFS eyes in many cases have Kmed values below 41.5 (Maumenee 1981; Heur et al. 2008; Sultan et al. 2002); hence, the corneal curvature was flatter in MFS patients. A retrospective case-control study by Chen J et al., including 55 eyes of the MFS patients with lens subluxation vs control group, reported similar results (40.54 ± 1.57 D vs 42.82 ± 1.46 D). Similarly, Konradsen et al. in 39 eyes with MFS found a flatter K reading of 42.2 ± 1.9 versus 43.4 ± 1.4 D. Gehle P et al. studied 285 eyes of MFS and found similar results (mean K of 41.78 ± 1.80 diopters (D) versus 43.05 ± 1.51 D). Similar results were found by Beene L. C. et al., Kinori M et al., and Luebke J et al. suggesting that this as a diagnostic tool for suspected MFS.
However, our case of MFS revealed steep mean keratometry values of 70.7 in OD and 67.5 D in OS in tomography, which also correlated with our clinical examination findings of keratoconus in both eyes. Keratoconus is at times reported to be associated with MFS, but very few case reports have been published, and to the best of our knowledge, no studies have reported a clear association between these two diagnoses. The aetiopathogenesis of flatter cornea in MFS cases can be correlated with progressive distension of the ocular tissues (cornea and sclera) due to abnormal collagen synthesis resulting in soft and weak tissue which results in uniform bulging of corneal tissue and a flat cornea. Keratoconus, like MFS, is believed to result from abnormal collagen synthesis in association with genetic and cellular factors. However, instead of being steeper and irregular, the corneas of MFS patients are flatter and regular. This gives rise to a paradoxical association between the two which evokes the need to rethink the aetiology of keratoconus. The genetic association of abnormal collagen synthesis with MFS is well established, while the association of abnormal collagen with keratoconus is a hypothesis, which becomes further questionable. Other factors, like microtrauma, contact lens usage, chronic ocular allergies, or external environmental factors may have a stronger association with keratoconus which needs to be established.
| Conclusion|| |
Although a rare presentation, concurrent Marfans syndrome and keratoconus should be considered when reviewing the ocular health of Marfans syndrome patients and appropriate management steps should be taken upon the diagnosis. Further, abnormal collagen synthesis as a proposed aetiology for keratoconus seems debatable and needs to be revisited.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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