What is Microphthalmia With Cyst?
Microphthalmia is a common birth defect that affects the eyes, making them smaller than usual but still identifiable.[1] This differs from anophthalmia, which is when the eye is completely missing due to problems during early development. There is a rare form of microphthalmia that also involves a cyst. This condition, known as congenital microphthalmia with cyst, should not be confused with another condition called a congenital cystic eye, or anophthalmia with cyst.[2]
Microphthalmia with a cyst is a serious birth defect that needs quick attention for the best results. The earlier treatment begins, the better the outcome usually is.
What Causes Microphthalmia With Cyst?
The development of ‘microphthalmia with cyst’, a condition where the eye is abnormally small and contains a fluid-filled sac, is rooted in how our eyes form before birth.
Typically, a specific part of the eye called the ’embryonic fissure’ starts to close when we’re 11mm in size in the womb and is completely closed once we reach 18mm. This closure process begins even before the 6-7th week of pregnancy.
As the parts of our eye-in-the-making grow at different rates, the edges of the fissure can start to bend outwards. In some cases, the retina, the layer of tissue at the back of the eye that senses light, can finish growing before the edges of the fissure join. This can prevent the fissure’s closure resulting in an ocular defect known as ‘coloboma’.
In cases where the edges don’t meet at all, the different layers of the retina may start to balloon outwards and collect fluid, leading to the growth of a cyst.
The cyst can develop in different ways. Some believe that tiny, hair-like projections in the inner layer of the cyst, which is made up of supportive ‘glial’ tissue, may contribute to the collection of fluid in the cyst. Others suggest that the cyst could communicate with the space beneath the arachnoid matter, one of the membranes covering the brain and spinal cord, allowing more fluid to enter the cyst and facilitate its expansion. The cyst can also enlarge due to an aggressive growth of the glial tissue, although this isn’t cancerous.
The diagnosis of microphthalmia with cyst depends on the stage at which the eye’s normal development is disrupted. If the disturbance happens between the 6th and 7th weeks of pregnancy, when basic eye structures are already present, the result is typically microphthalmia with cyst. Alternatively, if the disruption occurs earlier, preventing a structure called the ‘primary optic vesicle’ from forming correctly, the result is a condition called ‘anophthalmos with cyst’, where the eye is entirely absent.
Whether or not factors during pregnancy contribute to the development of this condition is still a matter of discussion. It’s important to identify any related genetic syndromes and provide the appropriate genetic counselling. Although most cases of microphthalmia with cyst are isolated, there have been recorded occurrences among identical twins and siblings.
Risk Factors and Frequency for Microphthalmia With Cyst
Microphthalmia is a condition that affects between 1.4 to 3.5 out of 10,000 newborns. However, there’s not much information available about the demographic profile of one particular sub-type, known as microphthalmia with cyst. It’s reported to be much rarer, affecting 0.3 to 0.6 per 10,000 births.
- Microphthalmia with cyst is not inherited and affects both genders equally.
- It usually shows up within the first few months after birth.
- It can often be detected as early as the newborn stage.
- In most cases, it affects one eye, but it can appear in both eyes.
Signs and Symptoms of Microphthalmia With Cyst
Patients with eye problems typically come to an ophthalmologist with indications such as lifelong vision issues, swelling under the eye, a firm blue lump that can sometime be seen through the transparent part of the eye, a mass in the orbit of the eye, outward bulging of the eye, or inability to open the eye since birth. There could be additional related conditions such as coloboma of the iris or optic disc, cloudy cornea, small cornea, shallow front part of the eye, angle-closure glaucoma or a pupillary membrane. It’s critical to check the health of the other eye in cases where only one eye is affected to rule out potential underlying diseases.
In cases of microphthalmia with cyst, it’s also crucial to look for other potential body abnormalities. These can include small head size, heart rhythm issues, a hernia of the brain, cleft lip, a missing corpus callosum in the brain, a flat nose, underdeveloped lungs, missing kidneys, and brain abnormalities, particularly when both eyes are affected by the disorder.
- Lifelong vision issues
- Swelling under the eye
- Firm blue lump visible through the corner of the eye
- Outward bulging of the eye
- Inability to open the eye since birth
- Coloboma of the iris or optic disc
- Cloudy cornea
- Small cornea
- Shallow front part of the eye
- Angle-closure glaucoma
- Pupillary membrane
- Other body abnormalities (if diagnosed with microphthalmia)
Testing for Microphthalmia With Cyst
Microphthalmia with cyst, a condition where the eye is abnormally small and has an associated cyst, is categorized into three types according to Duke-Elder classification:
* Type 1: The eye appears relatively normal with a cyst that cannot be seen in a regular examination.
* Type 2: The eye is severely misshaped with a clearly visible cyst.
* Type 3: A large cyst has pushed the eye backward to the point that it is not seen during an examination.
Doctors primarily diagnose microphthalmia with cyst through a physical examination, but imaging plays an essential role for confirmation. The quickest and most accessible initial test is standardized Ultrasonography (USG A + B-scan), a non-invasive procedure that reveals the eye’s status.
If doctors require more information, Magnetic Resonance Imaging (MRI) provides valuable insights into potential neurological abnormalities without radiation exposure, making it safe for children. The MRI could show communication channels between the eye and the cyst. An additional diagnostic tool, Diffusion-weighted MRI, may help distinguish between a rapidly growing cyst and a cancerous tumor.
Computed Tomography (CT) scan is another helpful tool that outlines bony structures, particularly when planning surgery for underdeveloped eye sockets. CT’s three-dimensional reconstruction informs presurgical planning. However, because CT scans involve radiation, their use should be cautious, especially in children.
Microphthalmic eyeballs and orbital cysts have sizes that categorize them as mild, moderate, and severe. The microphthalmic globe is classified as mild (17-21mm), moderate (12-16mm), and severe (<12mm). Likewise, the orbital cyst may be small (<10mm), moderate (>10mm to 20mm), or large (>20mm).
Once the diagnosis is confirmed through physical examination, imaging, and tissue sample analysis, it is important to assess the eye’s potential for vision. Evidence suggests that roughly 80% of microphthalmia cases with a corneal diameter of 5mm or less do not perceive light. If the vision potential is uncertain, Visual Evoked Potential, an eye test that measures electrical signals in the vision system, maybe helpful.
It’s also essential to evaluate and address any associated health conditions. Therefore, a pediatric review is recommended for comprehensive assessment and management.
Treatment Options for Microphthalmia With Cyst
Microphthalmia with cyst is a condition where an individual has smaller than usual eyes, often accompanied by a fluid-filled sac (cyst). There aren’t strict guidelines on how to manage this condition, but a few key factors guide the approach:
1. Age when symptoms first appear
2. Size of the eye socket
3. Growth pattern of the cyst
Before going for visual and cosmetic rehabilitation, it’s essential to ascertain that the undersized eye has no visual capacity.
The eye socket space in a healthy individual usually expands up to the age of about 5 or 6 years, and then expansion slows down. In individuals with microphthalmia, the presence of a cyst may help in the growth of the eye socket, thus lessening the difference between the two eyes. Therefore, it’s crucial to carefully consider surgery in children less than 7 years old.
The immediate removal of the cyst usually happens when:
1. The eye prosthesis doesn’t fit well or the cyst affects the shape of the eye socket
2. The cyst grows quickly due to bleeding into the cavity. In such cases, the fluid becomes dark red, unlike the typical translucent yellow.
3. The cyst bulges through gaps in the eyelids.
In kids younger than 7, prosthesis therapy should start at the earliest observation to achieve the best results. The size of the artificial eye gradually increases with the child’s growth. If the eye socket’s volume is severely decreased (less than 85% of the normal eye), expandable eye prosthesis is the preferred approach.
Prosthesis size directly correlates with socket expansion. Expandable implants, in contrast to stable spherical ones, stimulate the growth of the bony eye socket in undersized juvenile sockets. Natural slow-growing implants, like Dermis Fat Graft (DFG), provide an effective option for socket reconstruction.
Artificial expandable implants include hard spherical implants, inflatable soft tissue expanders, and hydrogel implants that expand when hydrated. All these implants have certain pros and cons.
Integrated tissue expander is a US-FDA approved expander inserted through a small cut at the corner of the eye that minimizes tissue loss and additional surgeries.
Surgical removal is the suggested method to get rid of the cyst. Aspiring the cyst fluid before surgery is another option, but it has a high recurrence rate, and hence, not the preferred first course of action. While some advocate the use of sclerotherapy (injecting medicine into the blood vessel to shrink it), the scarcity of evidence calls for prudence while opting for this method.
In severe cases of microphthalmia with no visual potential, removing the undersized eye and replacing it with an artificial eye in the same setting is considered.
Eyelid surgery or socket reconstruction using grafts should be reserved for later in life. For patients with a smaller eye opening and increased distance between eyes, corrective surgeries like canthoplasty can be beneficial. Customized prosthesis assures enhanced outcomes.
Bone graft surgeries to expand the eye socket space should be considered only as a last resort in undersized eye sockets.
What else can Microphthalmia With Cyst be?
When it comes to diagnosing a condition based on symptoms like a disappearing globe (the visible part of the eye), two conditions might be considered: congenital cystic eye and microphthalmia (a small or underdeveloped eye) with a cyst. It can be challenging to distinguish these two conditions just by looking, so further medical tests might be needed.
An interesting point to remember is that a cyst linked to congenital cystic eye is usually found on the upper and central part of the eye socket, while microphthalmia cyst does not show very primitive eye structures when examined under a microscope.
On the other hand, if an eye condition rapidly worsens, it might be a sign of cancer. Here are some other ailments that might present similar symptoms as an intra-orbital (inside the eye socket) cyst associated with microphthalmia:
- Dermoid cyst
- Epidermoid cyst
- Arachnoid cyst
- Meningocele
- Orbital teratoma
- Primary optic nerve sheath cysts
- Encephalocele (a defect in the skull that allows the brain to protrude)
With all of these potential conditions, it remains critical to conduct a thorough evaluation for a precise diagnosis.
What to expect with Microphthalmia With Cyst
Microphthalmia with a cyst, a condition where the eye is abnormally small and is accompanied by a fluid-filled sac, tends to have worse outcomes than other variations of microphthalmia. There are several factors that may lead to a less favorable outcome or prognosis:
1. Lack of potential for vision, confirmed through specialized electrical tests of the eye.
2. More severe forms of the disease.
3. An insufficient volume in the eye socket.
4. Getting diagnosed at an older age.
5. Removing the cyst before 7 years of age unless it’s necessary. It’s generally advised to leave a cyst alone in children under the age of 7, as it helps in the growth of the eye socket.
6. Undergoing eyelid surgery and eye socket reconstruction before puberty.
7. Removing the eye (enucleation/evisceration) without inserting an orbital implant.
8. Early discontinuation of devices used to expand the socket in childhood or refusal to maintain the corrective eye prosthesis.
9. Inability to keep the socket and prosthesis clean.
10. Not attending follow-up appointments regularly.
Possible Complications When Diagnosed with Microphthalmia With Cyst
The most concerning problems of this complicated condition often involve physical changes to appearance and loss of vision.
There are also risks related to surgery. These may include:
- Bleeding
- New infections
- Formation of extensive scarring after surgery
- Tightening of the eye socket
- Reoccurrence of the condition
- A buildup of blood in the eye socket (also known as an orbital hematoma)
Another set of complications can happen if grafting is involved in the treatment. These might involve the shrinking and dying off of fat tissues (or “fat atrophy and necrosis”) when using a DFG (dermis fat graft). Thankfully, the instances of fat shrinking are not common in children, which means that this method can still be a useful option for replacing lost volume in these cases.
Preventing Microphthalmia With Cyst
Microphthalmia with cyst is a complex condition where the individual has a smaller eye that may also have a cyst. It’s not only about the physical looks, but it can also affect how the eye works and may also impact a person’s social life. The patient and their parents should be well aware of the condition and its impacts.
In situations like these, discipline in using eye-shaping devices and orbital expanders is crucial. These tools can refine the appearance and function of the eye. Guidance should also be provided to the patient and their family, explaining clearly what they can expect with the condition moving forward.
It’s important to explain the value of regular check-ups with the eye surgeon, the ocularist (person who makes and fits artificial eyes), and the rehabilitation team. These follow-ups will ensure that the patient is progressing well and any concerns are addressed promptly.
Even if the patient’s vision may be limited, it is still crucial to focus on cosmetic and visual improvements. Making the eye look more normal and maximizing any remaining vision are key steps in ensuring better results when managing this condition.
