Eye problems

Why does the finding of a dislocated lens need to be investigated?

A dislocated lens is often the first sign identified in a person with the Marfan syndrome. While dislocated lenses may severely interfere with visual development and function, it is the accompanying cardiovascular manifestations of the Marfan syndrome that may lead to severe morbidity. As a result, all people with lens dislocation should be evaluated further.

Eye care professionals should play a significant role in detecting the Marfan syndrome. An eye care professional who suspects the Marfan syndrome should urge the patient to see a medical geneticist and a cardiologist for a complete evaluation and a definitive diagnosis.

What are the ophthalmologic problems caused by the Marfan syndrome?

One or more of the following conditions are common among persons with the Marfan syndrome: high refractive error, flattened corneal curvature, dislocated lenses, early onset cataracts, glaucoma, retinal detachment and strabismus.

Most people with the Marfan syndrome are myopic (near-sighted) and have astigmatism (visual distortion). Approximately 65 percent of people with the disorder have dislocated lenses (ectopia lentis). The lens may be markedly off center or so subtly dislocated that an ophthalmologist might miss the dislocation without fully dilating the pupils.

Dislocated lenses occur in several other conditions, most commonly after trauma, but their presence is a strong indication of the Marfan syndrome and warrants further evaluation. A slit lamp examination is necessary to identify the lens dislocation. Cataracts often form in middle age of people with the disorder. Retinal detachment is more common in people who have the Marfan syndrome. Glaucoma will also develop in about 35 percent of people with the Marfan syndrome during their life time, often at an earlier age than in the general population.

What is the standard ophthalmic treatment?

Many of the ocular problems associated with the Marfan syndrome are induced by the lenticular and axial myopia. They can be corrected with glasses or contact lenses (special flat contacts may be required for proper correction). Meticulous retinoscopy is essential for adequate optical correction, and full correction is desirable. Corneal refractive surgery (laser keratotomy) is contraindicated in most people with the Marfan syndrome if the corneas are markedly flattened already.

Cataracts are much more common in patients with the Marfan syndrome than in people who do not have the disorder, and often occur by the age of 40 or 50. Implant surgery is quite routinely performed and new techniques for lens removal and implant have produced very high success rates. It is essential that the surgery be performed at one of the ophthalmology centers that recognizes the surgical complications likely to occur in people with the Marfan syndrome; that is, vitreous loss, rupture of the residual zonules and extension of the capsulotomy.

Good results in patients with dislocated lenses can be obtained with the use of aphakic (refracting around the lens) glasses in combination with Atropine sulfate 1% ophthalmic drops to enlarge the pupil as an alternative to surgery.

Lens dislocation is rarely, if ever, present at birth, and may be first noted at all ages, most commonly prior to 10 years of age.

Special attention must be paid to identifying children with amblyopia, or lazy eye. It is essential that treatment be started prior to the age of 6 or 7 years in order for sight to be recovered in the weaker eye.

People with the Marfan syndrome should be taught to recognize the signs of retinal detachment and seek immediate consultation by an ophthalmologist.

Because glaucoma is more prevalent among people with the Marfan syndrome than people who do not have the disorder, intraocular pressure measurement should be part of a routine annual examination. Low tension glaucoma is also seen in people with the Marfan syndrome. If medical management is not successful, results from surgery have been excellent.

Annual ophthalmic examinations are encouraged, including refraction, intraocular pressure measurement and evaluation of the peripheral retina. Assessment of the optic nerve head is also mandatory.

Source-The National Marfan Foundation nov 2005