Several eye conditions seen in people with Marfan syndrome also occur in the general population. However, others, such as dislocated lenses, are rare in the general population but common in people with Marfan syndrome. Overview
Q&A OVERVIEW One or more of the following conditions are common among persons with Marfan syndrome: high refractive error, flattened corneal curvature, dislocated lenses, early onset cataracts, glaucoma, retinal detachment and strabismus. Most people with 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 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 Marfan syndrome. Glaucoma will also develop in about 35 percent of people with Marfan syndrome during their life time, often at an earlier age than in the general population.
A dislocated lens is often the first sign identified in a person with Marfan syndrome. While dislocated lenses may severely interfere with visual development and function, it is the accompanying cardiovascular manifestations of 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 Marfan syndrome. An eye care professional who suspects Marfan syndrome should urge the patient to see a medical geneticist and a cardiologist for a complete evaluation and a definitive diagnosis.
Many of the ocular problems associated with 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 Marfan syndrome if the corneas are markedly flattened already.
Cataracts are much more common in patients with 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 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 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 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 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. Q & A What are the symptoms of lens dislocation?
The symptoms of lens dislocation depend on severity and may vary from mild myopia to severe myopia, astigmatism and fluctuating vision. In addition, vision may be severely blurred. Lens dislocation can only be confirmed by an ophthalmologist who uses a slit-lamp eye examination after fully dilating the pupil. How many people with Marfan syndrome have lens dislocation and at what age do the lenses dislocate?
Approximately 65 percent of people with Marfan syndrome will develop dislocated lenses typically, but not always, before the age of 10. Dislocated lenses are rarely seen at birth, but may occur by 3-4 months of age. Lens dislocation is not a static event and may be progressive as seen in 16% of pediatric cases and 8% of adults. Lens dislocation tends to affect both eyes but may be worse in one eye than in the other. When and why should removal of the lenses be considered?
There are few absolute indications for lens removal; they include: glaucoma, retinal detachment, corneal edema and intraocular inflammation. People with even a total lens dislocation may not need surgery for decades. In the largest study of people affected by Marfan syndrome, the most common reasons for surgery were lens dislocation with fluctuating vision; progressive cataracts; and uncorrectable vision.
Although a dislocated lens is not able to adequately provide its primary function of fine-tuning visual acuity, it will still be able to help balance the pressures in the eye between the anterior and posterior chambers. Lens removal in young children raises the risk for retinal detachment and makes surgery for intraocular lens replacement later in life, when the eye is fully grown, more risky and technically difficult. We prefer delaying, if medically possible, lens removal and implantation of intraocular lenses until the later teen years, once the eye is more likely to have finished growing. The more stable the ocular parameters, such as a healthy retina and an eye that has stopped growing, the better will be the calculations for the lens implant. Therefore, a decision to remove the lenses depends upon the need for improved acuity versus the stability of the ocular measurements. Are there special considerations for lens removal and replacement in people with Marfan syndrome?
The use of anterior chamber lenses is contraindicated for people with Marfan syndrome because their eyes tend to be larger than normal and have abnormally deep anterior chambers with a recessed angle (standard anterior chamber lenses tend to be to small). Complications from anterior chamber lenses include excess movement of the lenses (windshield wiper effect), corneal decompensation, inflammation of the iris, glaucoma, pain and the need for corneal transplantation. Large, rigid posterior chamber intraocular lenses are recommended for people with Marfan syndrome. These lenses should always be sutured in place. Why do so many children with Marfan syndrome have refractive errors?
There are many causes of refractive errors in children with Marfan syndrome. Often, the eyeball is large or too long, which keeps light rays from focusing on the retina and causes myopia or nearsightedness. In other cases, the position of the lens or the shape of the eye (if it is shaped like a football) may cause astigmatism. In either case, it is important for the child's eyes to be checked regularly to ensure the proper prescription. From a diagnostic and treatment standpoint, it is essential to evaluate the eyes of all children as early as possible because if the brain has not perceived good vision in both eyes by the age of 10 or 12 at the latest, achieving good vision might not be possible. What is amblyopia?
Amblyopia is the diminution of vision with reduction in vision in one or both eyes. If there is a preference for one eye, amblyopia treatment may be required. This may consist of patching of the good eye to encourage use of the other eye, appropriate use of glasses or other amblyopia treatment modalities. What is strabismus?
Strabismus is misalignment of the eyes. It is present in 19-45% of people with Marfan syndrome (and only 3-5% of the general population) and may, in fact, be a presenting sign of the disorder. While strabismus in the general population is usually an inward deviation of the eye (esotropia), the Marfan population usually has an outward deviation (exotropia). There is also an increased incidence of horizontal misalignment among people with Marfan syndrome (12%) as opposed to the general population (2-5%). Strabismus can result in some visual loss. Nearly half of people with strabismus also have amblyopia.
About 95 percent of people with strabismus can attain excellent visual acuity if they are wearing the proper glasses and are treated for amblyopia. What are the special eye concerns for adults with Marfan syndrome?
The ocular complications resulting from Marfan syndrome in adulthood include cataracts, glaucoma and retinal detachments. Approximately 30 percent of people with Marfan syndrome will develop glaucoma in their lifetime. Repair of complications from an earlier surgery may occur in older persons, although the incidence of needed repairs may become less frequent because the outcomes from contemporary surgery are now much better. Is laser correction of myopia recommended for people with Marfan syndrome?
Laser correction can correct myopia (nearsightedness) up to -10 diopters. Most people with Marfan syndrome do not qualify because their nearsightedness is greater than -10 diopters. Minor cases of myopia can be corrected via laser surgery in people with Marfan syndrome if they do not have lens dislocation. If an affected person does have a lens dislocation, laser surgery is contraindicated because it will make the dislocation worse. Additional information is needed about the experiences of those with Marfan syndrome who have had laser correction of myopia to help determine if this procedure is worth the risk for affected people. What are the symptoms of retinal detachment?
These early symptoms may indicate a retinal detachment: - Flashing lights
- New floaters
- A gray curtain moving across your field of vision
These symptoms do not always mean a retinal detachment is present, but you should see your eye doctor immediately if any of these signs occur. Can head trauma cause retinal detachment in people with Marfan syndrome?
Head trauma can cause retinal detachment in anybody, and those who are highly myopic are always predisposed to retinal detachment. For people with Marfan syndrome, however, retinal detachment can happen spontaneously.
|
