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Clinical Update: Pediatrics
Gentle Care for the Anophthalmic or Microphthalmic Child
Eye contact in human interactions is a universal medium of social exchange, and so much more than vision is lost when a baby is born with an absent or undersized eye. Without the appearance of normal eyes, children with anophthalmia or microphthalmia face social ostracism with lifelong consequences, said James H. Merritt, MD, an oculoplastic surgeon who, along with ocularist William R. Trawnik, BCO, has treated these conditions in their Dallas practice for 25 years. “Although there may be different solutions for different children,” said Dr. Merritt, “we try to maximize their potential, no matter how severe the condition, with the goal of enabling prosthetic wear.”
Dr. Merritt and Mr. Trawnik share an approach to managing these patients that both advances some current treatment models and, on some points, departs from them.
Missing Eyes, Small Eyes
Anophthalmia and microphthalmia are relatively rare ocular defects resulting from arrested development of the primary optic vesicle. Anophthalmia leaves no visible ocular remnant; microphthalmia produces an eye but with markedly reduced volume. Whether unilateral or bilateral, these conditions can present with a wide spectrum of features, and more than half are accompanied by other ocular defects or systemic problems, such as blepharophimosis, cardiac or central nervous system abnormalities, genital malformations, feeding difficulties and metabolic disturbances, or mental retardation.1
Genetic mutations and gestational insults may be variously involved in interrupting ocular cell migration during embryogenesis. “We think of anophthalmia and microphthalmia as the ocular equivalent of cleft lip and palate,” said Dr. Merritt. “Along the rostral neural tube, there is a failure to close or an arrest of development during differentiation.”
Team care. For these children, the ophthalmologist must collaborate first with the pediatrician to assess the need for family support services, and then with the ocularist to achieve maximal orbital development through prosthetic wear. “This is an effort that has to be coordinated between the oculoplastic surgeon and the ocularist,” said Stephen P. Christiansen, MD, professor of ophthalmology and pediatrics at the University of Minnesota in Minneapolis. “The ocularist is crucial, taking impressions of the orbit and expanding and increasing the size of the conformer, so the bony growth of the orbit can be progressive.”
Physical assessment. Dr. Merritt and Mr. Trawnik have developed a scoring system for anophthalmia/microphthalmia in which the unique features of each case can be documented:
No matter how severe the condition, Dr. Merritt noted, it is important to assess both eyes because a normal-sized fellow eye may also have pathology, such as:
Genetic assessments. “Anyone with a child so affected is encouraged to seek a genetic assessment,” said Dr. Merritt, “which can give a heads-up in terms of what to expect and in family planning.” It is also helpful to examine other family members for ocular pathology related to these conditions and to seek a three-generation family history of eye anomalies. Reevaluation of the child at age 4 or 5 by a medical geneticist can also help spot features of larger syndromes.2
Treat Now or Later?
Divergent schools of thought now govern the management of the anophthalmic or microphthalmic child. One suggests performing somewhat radical procedures, such as rapid expanders early on or craniofacial orbital bony expansion in later childhood, to correct the deficient volume. This latter approach does a big disservice to young patients, said ocularist John Pacey-Lowrie, consultant to the Microphthalmic and Anophthalmic Children’s Society in Nottingham, U.K., who himself was born with a microphthalmic eye that was not addressed early. “You’re not going to walk around with one eye looking different if you can possibly help it,” he said. “We had a classic case this week here in England, a baby born with severe microphthalmia whose parents were told, ‘Take him away . . . there’s nothing we can do. When he’s five, he can have a prosthesis.’”
Start early for a promising future. A newer approach, favored by Mr. Pacey-Lowrie as well as by Dr. Merritt and Mr. Trawnik, advocates early intervention with the initiation of a custom-tailored ocular prosthesis. The reasoning is based on the fact that, at birth, a baby’s face is underdeveloped in comparison to the eyes, but rapid growth brings the face to within 90 percent of adult size by age 5. “As a normal eye grows, the pressure on surrounding tissues expands the bony orbit,” said Mr. Pacey-Lowrie. “But when a child is born with anophthalmia or severe microphthalmia, there is significant asymmetry of the bony orbits. The goal is to maximize growth with early, consistent and gentle prosthetic expansion therapy because if you wait too long, you will sacrifice precious bony growth.” He noted that some ophthalmologists consider ocular prosthetics “merely” cosmetic, rather than therapeutic, in nature.
Dr. Merritt challenges the notion that cosmesis is not important. “Families tell us that having a prosthesis with the appearance of a sighted eye makes a real difference as to how others interact with the anophthalmic or severely microphthalmic child.”
Go gentle, go gradual. Dr. Merritt and Mr. Trawnik try to begin gentle and gradual orbital expansion therapy within the first few weeks of life, especially in cases of anophthalmia. They explained that initiating expansion at such a young age will make an enormous difference in what is possible in prosthetics by young adulthood. That’s because associated adnexal abnormalities such as eyelid phimosis, conjunctival shortage and micro-orbitism further exaggerate asymmetry. Stimulating the socket to move gradually early on is “fitting to function,” said Mr. Trawnik.
Functional Expansion vs. Brute Force
Although there is near consensus among ocularists that early intervention is preferable, within that consensus there are more aggressive and more gradualist approaches.
Expand on command. Among the more aggressive treatments, silicone expanders are gradually filled with liquid such as saline on a weekly or biweekly basis. Alternatively, hydrophilic expanders are inserted dry and then expand to full size by osmotically absorbing surrounding tissue fluid in 36 hours.
Although hydrogel expanders reportedly circumvent repeated incremental prosthetic fittings, some controversy exists around their use. Dr. Merritt, for one, considers them an overly aggressive approach. “The hydrogel expander doubles in diameter and increases in volume roughly eightfold in a little over a day. You don’t move teeth with braces overnight but over years. You need to apply the same principles to the anophthalmic and microphthalmic orbit.” In addition, according to Dr. Merritt, expanders are sometimes applied without the training and diligent follow-up required to be successful.
Termed “deformity by conformity” by Mr. Trawnik, this approach can cause canthal splitting or rebound contraction once the expander is removed, Dr. Merritt said. “Like stretch marks on a pregnant abdomen, orbital adnexal tissues that are expanded too rapidly respond with scarring.” The small eyelid soft tissue structures of the congenital anophthalmic socket do not have the elastic compliance to respond to rapid or aggressive expansion, he explained, and patients so treated can end up with difficulty wearing a prosthesis later.
Conform on your own. Dr. Merritt thinks a better approach is one that, again, parallels the principles of orthodontics. “Just as you can move a tooth through bone very slowly, we can encourage eyelid, conjunctival and bony development over years. What works best is the early prosthetic fittings and, later, staged orbital reconstructive procedures that have been proven safe and effective not only for anophthalmic/ microphthalmic children, but for children and adults who lose eyes to tumors, trauma and disease.”
For the gentler expansion therapy, an ocularist empirically fits the baby with a clear acrylic conformer, gradually enlarging it over six to 12 months. Then an alginate impression of the socket is made during an exam under anesthesia to aid the design of a custom-fit prosthesis tailored to the contours of the small socket. This prosthesis sits within the socket the way braces fit around teeth and is adjusted and gradually enlarged every two or three months early on and every six to nine months thereafter.
Lid surgery. Some surgeons choose to surgically perform an early lateral canthotomy or cantholysis in cases where shortening or phimosis of the eyelids is severe. Others, including Dr. Merritt and Mr. Trawnik, have abandoned early lid procedures because the lateral canthus helps capture, retain and stabilize the prosthetic expansion process. “Several years after the eye has progressed with gradual prosthetic enlargement, we may surgically elongate the lateral canthal angles,” said Dr. Merritt. The conjunctival surface area shortage commonly causes eyelash rotation to the prosthetic surface in most severe anophthalmic cases. We have learned to “live with” the eyelash entropion early on, said Dr. Merritt. “When a spherical implant is placed in the muscle cone, the eyelash entropion can improve or later be treated with oral mucosal grafting to the posterior lid margin.”
Blepharophimosis surgery. Many anophthalmic and some severe microphthalmic patients also have blepharophimosis, which is a triad of severe ptosis, eyelid phimosis and telecanthus. These cases may benefit, said Dr. Merritt, from Mustarde medial canthal reconstruction for reduction of telecanthus and from ptosis frontalis suspension surgery in later stages of management.
Implants. Once optimal growth has been attained with gradual prosthetic enlargement, it’s time to insert an implant “within the muscle cone,” said Dr. Merritt. Options for implants include dermis-fat grafts, hydroxyapatite, Medpor or scleral-wrapped PMMA spheres. Some implants can be attached to ocular muscles, allowing movement of the prosthesis. However, these can decrease conjunctival elasticity or complicate cases in which implant removal is later warranted to improve prosthetic fit. “We prefer a scleral wrapped acrylic sphere and can usually attach the small muscles to hold the implant centrally in the socket. This implant is usually a 12-, 14- or 16-mm sphere. Porous implants, hydrogel rapid expansion implants and oversized spheres are not well-suited to these situations in our experience,” Dr. Merritt said. The best timing for implant placement is when the ocularist reports no further progress with prosthetic expansion alone. Often at this juncture the prosthesis has become so large relative to the eyelids and socket that one has difficulty taking the prosthesis in and out.
In some cases of severe microphthalmia, light from the remnant eye can actually be a hindrance to a normal fellow eye, said Mr. Pacey-Lowrie. “Often you’re doing someone a favor by eliminating it.”
Depending on the clinical situation, long-term management of the anophthalmic/microphthalmic patient varies. Ocularists may manage mild to moderate microphthalmia for life without surgery. But severely microphthalmic eyes may need to be treated similarly to anophthalmic eyes—by an MD/ocularist collaboration, said Dr. Merritt. He added that he hopes insurance companies as well as ophthalmologists in the field will come to appreciate the value of early and gentle orbital expansion therapy for anophthalmia and microphthalmia. “It is an unfortunate oversight when these children are not referred to an ocularist and oculoplastic specialist for early management. We have managed so many cases—some to adulthood—and feel we can confidently advise and assure families how much can be done and what the timetable is. We have, unfortunately, also seen too many patients who have had aggressive, poorly planned surgical procedures that were counterproductive.”
2 Bardakjian, M. S. et al. GeneReviews January 29, 2004. www.geneclinics.org.
None of the experts interviewed for this article report related financial interests.