What is Morning Glory Syndrome?
Morning Glory Syndrome (MGS) is a rare disorder that affects the part of the eye known as the optic disc from birth. This condition was first noted in 1970 by a researcher named Kindler, who reported ten cases of a unique optic disc abnormality. The optic disc, which is part of the nerve that connects the eye to the brain, was observed to have a shape that resembled a funnel. It contained a white, fibrous tissue in the center, and there was a circular region around it showing changes in the pigment of the retina (the lining at the back of the eye that senses light).
The blood vessels of the retina began as numerous straight thin branches at the edge of this unusual optic disc. Kindler named it the “morning glory disc” because it looks similar to a morning glory flower. This condition is considered rare and usually occurs sporadically.
This summary will provide an overview of the causes, frequency, tissue changes, symptom, conditions it can be confused with, related conditions, complications, how it is evaluated, and how it can be managed when it comes to Morning Glory Syndrome.
What Causes Morning Glory Syndrome?
The Morning Glory Syndrome (MGS) is not fully understood. It could possibly be caused by an issue with the primary soft tissue of our body, incomplete development of a specific area in our eyeball, or not having a properly closed backside of the eyeball. Additionally, irregularities in the central tissue and abnormal blood vessel patterns might also indicate a problem in the original cells that form the brain and spinal cord during pregnancy.
It was reported that eight patients with optic nerve disorders were found to have mutations in their PAX6 gene. This gene is crucial in the development of the eye and is found in various eye tissues and the central nervous system. However, others failed to find these gene changes in the same condition.
Several studies suggest that MGS might be inherited, as instances of mothers and daughters having MGS were reported. The case of a patient with a disorder that affects the patient’s iris and a morning glory syndrome in one eye, and another optic disc disorder in the other eye has also been described. The patient’s mother had the iris disorder too, but no other abnormalities in the eye. This suggests that MGS could vary on a scale that includes optic disc pit and optic disc coloboma, which are different types of eye abnormalities.
It has also been suggested that there could be improper fusion of the backside of the eyeball, which could make the disc and the adjacent retina pop out. Furthermore, anomalous differentiation of the middle embryonic layer could result in a not properly closed backside of the eyeball and a specific area in our eyeball, causing the retina and optic nerve head to pop out.
It has been reported that certain eye abnormalities are inherited due to the mutation in the MMP19 gene located on the 12th chromosome. These eye conditions include optic disc coloboma, optic disc pit, enlarged optic disc, and MGS.
Risk Factors and Frequency for Morning Glory Syndrome
Moyamoya syndrome (MGS) is a rare condition, affecting both males and females equally. It’s mainly found in one side of the brain, but about 16% of cases involve both sides. Most people receive a diagnosis by the age of two, although some might not know they have it until they’re five. Usually, this late diagnosis happens because these individuals live in rural places or have a lower income and are less aware of their health conditions. The related condition, familial circle of Willis arteriopathy (CODA), usually affects both sides of the brain in about 65% of the cases.
- Moyamoya syndrome (MGS) affects 2.6 out of every 100,000 people.
- Both males and females are affected equally by the condition.
- In the USA, it’s less common among black people.
- Most of the time, it affects one side of the brain.
- About 16% of cases involve both sides of the brain.
- Most people are diagnosed by the age of two.
- Some people are diagnosed around the age of five due to a lack of medical awareness.
- In the related condition, familial circle of Willis arteriopathy (CODA), both sides of the brain are usually affected (around 65% of cases).
Signs and Symptoms of Morning Glory Syndrome
In a study involving 44 patients and 51 eyes, the common age for the occurrence of CODA (a type of eye condition) is approximately 8.8 years, but it can range from as young as 3 months to as old as 46 years. Most patients first notice the condition through symptoms such as vision loss, crossed eyes, or a white reflection in the pupil. However, it doesn’t affect both eyes in everyone. In fact, it typically affects only one eye in about 85% of cases, with both eyes being affected in the remaining 15%. No specific gender is more likely to experience this condition, and it’s also rare to find it running in families.
Nearly 80% of patients with this condition may develop crossed eyes, where one of their eyes turns inward or outward. Patients often have a disc-like tissue in the center of their optic nerve, and the blood vessels in the retina (the layer at the back of the eye that senses light) might looks unusually straight and branch at sharp angles. Other signs include a retinal condition known as ‘macular capture’ and persistent fetal vasculature, which is an eye condition present since birth, could also be seen. Retinal detachment, when the retina pulls away from its normal position, is another condition that might occur.
In some cases, the retinal detachment may be linked to a connection between the space underneath the retina and the fluid-filled space around the brain and spinal cord. When this happens, the fluid in the spinal cord can flow into the space underneath the retina, causing it to detach. In rare cases, fluid leakage from the optic nerve or a complex condition involving new blood vessels and fluid leakage from the retina may cause retinal detachment. Even the other eye, which might seem unaffected, should be closely monitored for potential complications.
Testing for Morning Glory Syndrome
Optical coherence tomography (OCT), a non-invasive imaging test, is helpful in examining the abnormalities of the optic disc, a crucial area at the back of your eye. OCT can clearly outline changes like a layer on the surface of the retina pulling the retina inward, which has been seen in some cases of Morning Glory Syndrome (MGS), a rare defect of the optic disc. OCT can also define optic disc contraction, which is the optic disc shrinking in size during muscular tightening. Studies have observed that the optical disc contracts a few times each minute, and these contractions last for about 4 to 5 seconds.
Moreover, for patients with MGS having contractile optic discs, OCT angiography (a technique that visually maps the blood flow in the eye) shows a dense network of small blood vessels around the optic nerve. Also, OCT can detect subtle changes like small breaks around the optic disc or shallow retinal detachments. In some severe cases, OCT has aided surgeries for retinal detachment in patients with MGS. Tests using fluorescein angiography (a procedure to look at blood vessels and blood flow in your eye) are also helpful in seeing areas in the eye where blood flow is reduced or blocked.
It can often be challenging to diagnose MGS, as its symptoms may resemble those of other optic disc issues like optic disc coloboma, a condition where the optic disc forms incorrectly during pregnancy. Specific features help differentiate MGS from normal eyes, making diagnosis accurate. These include a cone-shaped optic disc, abnormal tissue in the optic nerve with space effacement (loss of the clear space), and discontinuity of the uveoscleral coat, the combined outer layers of the eye.
It’s crucial to know that MGS may go hand in hand with abnormalities in other systems of the body. Facial anomalies like cleft lip and palate, among others, are common. A rare condition called moyamoya disease, characterized by abnormal narrowing of brain arteries, could also be linked with MGS, making it essential for patients with MGS to be evaluated for moyamoya disease. Furthermore, kidney anomalies are common in patients with MGS and thus, should be assessed for hypertension and kidney disease.
Lastly, people with MGS may also have central nervous system abnormalities like the herniation of brain tissue (encephaloceles) or missing parts of the brain (agenesis of the corpus callosum). Some may also have nerve abnormality in their neovascular structures with many conditions reported such as like Chiari type 1 malformation. These signs should be considered for accurate diagnosis and effective treatment.
Treatment Options for Morning Glory Syndrome
For the proper management of MGS (morning glory syndrome), early identification and treatment are especially crucial. MGS can cause two eye problems – strabismus (misaligned eyes) and anisometropia (unequal refractive power in both eyes). Thus, these conditions need to be fixed to prevent amblyopia, also known as lazy eye – a vision development disorder where the eye fails to achieve normal visual acuity. This typically involves prescribing glasses following a complete eye refraction test.
In some cases, a patient might have squint or crossed eyes which may necessitate surgical correction. Another possible complication related to MGS is retinal detachment, an eye disorder where the retina peels away from its underlying layer of support tissue, in such a case, surgery is mandatory.
During this surgical procedure, a technique called Pars plana vitrectomy is implemented. In simple terms, the vitreous humor (jelly-like substance in your eye) is removed and replaced with a silicone-based substance or gas bubble to maintain normal eye pressure and hold the retina in place. The entire procedure involves several steps such as eliminating any potential abnormal tissue growth, draining out retinal fluid, laser treatment to seal retinal holes and prevent further breakage.
In certain cases of retinal detachment, it has been observed that the retinal tissues reattach themselves naturally without any surgical intervention. Such phenomena, though rare, should be considered when deciding on a surgical treatment option.
Regular monitoring of the healthy eye in cases of MGS affecting only one eye is critical as the unaffected eye may also develop complications such as a cataract or retinal detachment in the future. To manage these complications, an operation to remove the cloudy lens (phacoemulsification) may be performed, replacing it with an artificial one, or surgery to repair the retina may be necessary.
What else can Morning Glory Syndrome be?
Morning Glory Syndrome (MGS) often looks the same as an optic nerve condition called a coloboma, a condition where a large ubnormal part of the eye structure exists, often towards the bottom. It can affect the surrounding eye tissue and thin out certain areas. Coloboma can often be found alongside other eye conditions and may occur in one eye or both. Some patients may even exhibit optic nerve cysts.
Coloboma can also be linked with other health conditions, such as CHARGE syndrome, Walker-Warburg syndrome, Aicardi syndrome, Goldenhar syndrome, and Goltz dermal hypoplasia.
However, MGS is different in that it features a central optical disc that is either recessed or cone-shaped. It doesn’t deviate downwards, has extra tissue in the center, and has pigment disruption around the optic disc that isn’t found in coloboma. The blood vessels in MGS also emerge differently and it can be associated with different types of eye issues. It doesn’t feature the same microcornea and iris coloboma that are commonly found in optic nerve coloboma.
MGS can also resemble another condition called optic nerve head avulsion (ONHA), which usually happens due to heavy blunt force trauma. The optic nerve becomes a cavity filled with blood, potentially alongside other injuries. Medical imaging can help identify the damage.
Optic nerve aplasia (ONA) is another condition that can be mistaken for MGS. It’s a birth defect where the optic nerve is completely absent, as are the retinal blood vessels. A person with ONA will have no light perception and tests will find an absent optic nerve shadow.
Optic disc pit (ODP) is a condition where there is a cavity in the optic nerve which can be mistaken for MGS. However, vision is generally not affected unless complications arise.
An advanced stage of glaucoma called AGON can also resemble MGS with enlargement of the optical cavity and specific areas of thinning. It is also characterized by dislocated vessels and other specific changes.
Lastly, MGS can be mistaken for a condition called peripapillary staphyloma, a congenital anomaly where there is a deep cavity in the eye, but with a normal optic nerve head. However, unlike MGS, this condition is not linked with any other birth defects or systemic diseases.
What to expect with Morning Glory Syndrome
The outlook regarding vision is often not good for those with MGS. These patients tend to have significant vision errors and crossed or misaligned eyes (strabismus), which can result in lazy eye (amblyopia). They are also at a high risk of developing a detached retina, primarily because of abnormalities in the optic disc, the region at the back of the eye where the optic nerve meets the retina.
Children with this condition might not express any complaints about reduced vision, and many only get diagnosed coincidentally because of a chronic detached retina.
Following a successful retina surgery, the final visual result depends on how long the retina was detached and if there is any pre-existing lazy eye. Prolonged schisis, a split or separation within the retina, can lead to degenerative changes that further hinder vision recovery. Usually, vision clarity extends from 20/200, considered legally blind, to no perception of light at all. Even those without detached retinas typically have poor vision, often 20/200 or worse.
Possible Complications When Diagnosed with Morning Glory Syndrome
Strabismus that persists over time, along with eye conditions that aren’t corrected, can lead to a condition called amblyopia. This is a decline in vision that can still occur even if the patient receives treatment. A similar complication that arises when tissue in the eye pulls over the retina is retinal breaks. These can occur within the optic disc or at its border.
Finding these breaks can be difficult because the white scleral tissue in the optic nerve is not easily distinguishable from the thin retina. This struggle in identification can result in higher rates of retinal detachment and reattachment. Vision can also be impaired if the patient has prolonged retinal schisis, a condition where the retina splits in two. This can lead to the retina wasting away due to long-term buildup of fluid within and beneath the retina.
Other complications that can occur include new blood vessels growing in the retina near the optic nerve and the macula, and areas of the peripheral retina lacking blood leading to fibrous tissue growth and the pull of a retinal detachment.
- Long-term strabismus and uncorrected vision issues
- Amblyopia
- Retinal breaks
- Challenges in identifying breaks due to similar optic nerve and retina color
- Increased probability of retinal detachment and reattachment
- Long-term conditions like retinal schisis leading to atrophic retinal changes
- New blood vessels growing in the retina
- Peripheral retina without blood causing fibrovascular growth and retinal detachment
Preventing Morning Glory Syndrome
Patients should be given clear, easy-to-understand information about the potential projections and complications of MGS, a condition that affects the eyes. This condition requires a detailed check-up of not just the eyes, but the body as a whole. Also, it’s not just the patient alone who needs to be seen by an eye doctor. Family members should also be seen by an eye doctor as there could be risk factors that extend to them.
