AXENFELD-RIEGER SYNDROMEOphthalmologist Carolina Valdivia, MD responds to a question about Axenfeld-Rieger Syndrome and vision loss posed by a 35 year-old mother.  A 35 year-old mother from Lithuania writes:Hello Dr. Valdivia. My one-year-old baby girl has been diagnosed with congenital glaucoma in both eyes. Her intraocular pressure is 29 mmHg and I am administering Cosopt eye drops twice per day. She also has been diagnosed with myopia -2, iris mesodermal dysgenesis, and lens subluxation – all in both eyes. What can I do to save my daughter's eyesight?
Developmental or pediatric glaucoma can be congenital, infantile or juvenile depending on the age of onset in a patient. Congenital glaucoma occurs in the first three months of life, infantile between 3 months and 3 years, and juvenile from 3-35 years. These types of glaucoma are associated with developmental abnormalities in the iridocorneal angle in the anterior chamber of the eye. This is the angle formed by the juncture of the cornea and the iris. Depending on the age at which your daughter first was diagnosed, she either has congenital glaucoma or infantile glaucoma. Nevertheless, these terms often are used interchangeably. Thus, even though your daughter is one year of age, I will use the term congenital glaucoma in the remainder of my response, since this is the information that you provided. When glaucoma occurs in the first three years of life, it usually is accompanied by enlargements of the eyeball and the cornea. The medical term for this is buphthalmos. In this condition, the eyeballs appear larger than normal, due to elevated intraocular pressure inside the eye. Infant eyes are particularly susceptible to buphthalmos from elevated intraocular pressure because collagen filaments of the sclera (white part of the eye) are not yet rigid and easily can be stretched. Buphthalmos is a serious problem that requires urgent treatment to lower eye pressure, usually with surgery.Another way to distinguish glaucoma at this age is according to whether the baby only has abnormalities in the development of iridocorneal angle – the area where the cornea and iris meet and the location where fluid inside the eye called aqueous humor drains – or if there also are other ocular and systemic abnormalities, meaning abnormalities elsewhere in the body. As you mention in the information that you provided to me, your daughter has been diagnosed with the following problems in her eyes:
This means that your daughter has a situation in which there is congenital glaucoma along with other abnormalities in the eye, a condition referred to as Axenfeld-Rieger Syndrome. A syndrome is a group of coexisting clinical features and symptoms that characterize a particular disease or condition. In Axenfeld-Rieger Syndrome, both eyes usually are affected, buphthalmos typically is present, there often is a family history of the disease, and developmental problems may exist in other areas of the body.In case you have questions about the clinical features of Axenfeld-Rieger Syndrome that your daughter is presenting, I am going to briefly explain them. Since I will be using some technical terms, you might want to refer to the eye structure and eye anatomy pages for more detailed explanations. Primary Congenital Glaucoma. In Axenfeld-Rieger syndrome, this usually is of the open-angle type, meaning that the iridocorneal angle in the anterior chamber of the eye is open, as opposed to closed. When the angle is closed, the flow of aqueous humor in the eye is blocked. This raises pressure inside the eye, which, in turn, causes damage to the optic nerve and progressive vision loss. Although in congenital glaucoma the iridocorneal angle usually is open, blockage of aqueous humor outflow is impeded anyway, leading to buphthalmos. In this case, it is due to developmental problems in the trabecular meshwork, a structure located at the iridocorneal angle that filters aqueous humor before it exits the eye and returns to the bloodstream. Surgery for congenital glaucoma is designed to create a new opening in the trabecular meshwork in order to enhance aqueous humor outflow and lower pressure in the eye. Iris Mesodermal Dysgenesis. This is a somewhat antiquated term that refers to an underdevelopment or incomplete development of the iris stroma. The more commonly used term associated with Axenfeld-Rieger Syndrome is hypoplasia of the anterior iris stroma. The iris stroma is a layer of connective tissue that forms the supportive framework or scaffolding through which the muscle fibers of the iris pass and attach. The iris is a muscle that controls the size of the pupillary opening. If the stroma is underdeveloped, this tends to flatten the iris and affects how and where the muscle fibers attach to the anterior chamber wall. At the age of one year and beyond, the iris normally is located posterior to the scleral spur. The scleral spur is a thin protrusion of sclera into the anterior chamber. It attaches to the ciliary body posteriorly and to the trabecular meshwork anteriorly. In hypoplasia of the anterior iris stroma, muscle fibers do not attach properly. This can take the form of an inadequate number of attachments, incomplete or weak attachments, or inappropriate locations for attachments. Due to this problem, the iris can migrate over the scleral spur and partially occlude the trabecular meshwork, causing elevations in intraocular pressure and buphthalmos in infants and toddlers. It also is a likely causative factor for lens subluxation. Additionally, the muscles of the iris cannot function properly with underdeveloped stroma, which can lead to photophobia (sensitivity to light) and an asymmetrically shaped pupil. Lens Subluxation. Also called ectopia lentis, ophthalmologic lens subluxation is a condition characterized by a partial displacement or misalignment of the lens within the eye. This also is common in Axenfeld-Rieger Syndrome and likely is a secondary effect of hypoplasia of the anterior iris stroma. An underdeveloped iris causes the lens to lack structural support, allowing lens subluxation to occur. Lens subluxation also could be partially responsible for your daughter's myopia. Treatment for lens subluxation depends on whether the displacement is forward, toward the anterior chamber of the eye, or backward, into the vitreous chamber. Anterior lens subluxation is treated first with medication and ocular massage through a closed eyelid. Surgical treatment follows to prevent further complications. Posterior lens subluxation is treated surgically. Myopia. Also known as nearsightedness, myopia is a vision condition in which close objects are seen clearly, but objects farther away appear blurred. It occurs if the eyeball is too long or the cornea, the clear front cover of the eye, has too much curvature. Consequently, light entering the eye is focused improperly in front of the retina rather than onto it. Your daughter has a myopia of -2. Usually babies are farsighted. A finding of +1 or +2 in infants often is typical. Myopia is a common condition associated with Axenfeld-Rieger Syndrome because elevated intraocular pressure causes an enlargement of the eyeball (buphthalmos), which can change the length of the eyeball and curvature of the cornea. Effective treatment to lower her intraocular pressure to a normal range reduces buphthalmos and often improves myopia in cases of Axenfeld-Rieger Syndrome. One thing that concerns me is that your baby's intraocular pressure remains elevated (29 mmHg) despite treatment with Cosopt (Timolol + Dorzolamide). This means that she likely has some degree of buphthalmos. Medication options for infants are very limited. Either medications that are used in adults have not been proven safe in children or they cause adverse effects that are not tolerated by children.Because glaucoma threatens eyesight, ophthalmologists attempt to control this problem first in patients with Axenfeld-Reiger Syndrome and then move to address other issues, such as lens subluxation and myopia later. In infants, the treatment of primary congenital glaucoma associated with Axenfeld-Rieger Syndrome always is surgical. It is very important that your daughter be evaluated for surgery as soon as possible. The reason for this is that a sustained intraocular pressure of 29 mmHg can lead to optic nerve damage and progressive loss of vision. Unfortunately, ophthalmologists cannot reliably measure to what degree eyesight has been lost in an infant. Thus, surgery to allow the fluid inside the eye to drain and lower eye pressure to control buphthalmos is an imperative. The most common surgical procedures for primary congenital glaucoma are goniotomy and trabeculotomy. In goniotomy, the fibers of the trabecular meshwork are cut to eliminate any occlusion to aqueous humor outflow due to an underdeveloped trabecular meshwork. In trabeculotomy, a probe is used to tear through the trabecular meshwork to open it and allow aqueous humor to flow. An advantage of trabeculotomy over goniotomy is that it can be performed in eyes with hazy corneas. Goniotomy and trabeculotomy have success rates as high as 90% if they are performed between 2 months and 2 years of age. Surgeries performed on infants younger or older have lower rates of success. If goniotomy and/or trabeculotomy are unsuccessful in reducing intraocular pressure, your ophthalmologist may recommend the following alternative surgical procedures.
Because the features of Axenfeld-Rieger Syndrome compound each other, the success of surgery is lower compared to children diagnosed with primary congenital glaucoma alone. Despite this, surgical intervention still remains the best option. Remember, just because success rates are lower, this does not mean that there are no successes. There is hope that surgery will restore your baby's intraocular pressure to a normal range, preserving as much of her vision as possible. If you have other questions about Axenfeld-Rieger Syndrome or about its treatment feel free to write to me. Carolina Valdivia, MD
REFERENCES:Alward WL. Axenfeld-Rieger syndrome in the age of molecular genetics. American Journal of Ophthalmology. 2000;130(1):107-115. Samples JR. Childhood Glaucoma. In: Morrison JC and Pollack IP. Glaucoma: Science and Practice. New York: Thieme, 2003:181-196.
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I am very sorry about the challenges that you and your baby girl are facing.