Microspherophakia

What is Microspherophakia?

Microspherophakia is an uncommon birth defect that affects the shape of the lens in the eye, making it abnormally round. The condition is identified by a thicker lens with a smaller diameter. This condition is primarily caused by issues during the lens “strings” (zonules) development. Commonly, it affects both eyes and is signified by smaller, denser, and round lenses. Many times, mutation in a gene called LTBP2 is at the root of the problem.

Common issues that come along with microspherophakia include lens dislocation (where the lens moves from its usual position), high nearsightedness (difficulty in seeing distant objects clearly), difficulty in changing focus from distant to near objects (accommodation deficits), or increased eye pressure. In rare instances, microspherophakia has been associated with other eye diseases like retinitis pigmentosa, Axenfeld Rieger anomaly (abnormal development of the eye), and XYY syndrome.

What Causes Microspherophakia?

The root cause of certain eye conditions is related to the development of zonules, tiny fibers in your eye, during early development before birth. Genetic changes in certain genes, specifically the Latent TGF (transforming growth factor) binding protein-2 (LTBP2), ADAMTS17, and FBN1 have been shown to be a factor in these conditions.

The LTBP2 gene is found in parts of the eye like the drainage meshwork (trabecular meshwork), the ciliary processes (parts of the eye that produce a fluid called aqueous humor), and the lens capsule. This gene is structurally similar to the fibrillin protein and is responsible for creating elastic fibers that give structure to various parts of the eye.

The ADAMTS17 and FBN1 genes have been primarily identified as factors in a rare genetic disorder known as Weill Marchesani Syndrome, which often results in eye abnormalities.

Risk Factors and Frequency for Microspherophakia

Microspherophakia is often found in combination with other developmental anomalies and is also known to be a part of certain syndrome groups like the Weil Marchesani syndrome. The rate of occurrence for Weil Marchesani is estimated to be 1 in 100,000 people. While microspherophakia on its own has been noted in various ethnic groups, there hasn’t been much research conducted on its rate of occurrence. However, a study conducted in India found that 1.2% of children showing lens abnormalities in the clinic had microspherophakia.

Signs and Symptoms of Microspherophakia

Microspherophakia is a condition that usually affects both eyes. People with this condition often complain about poor vision and difficulty focusing. In some cases, they may also experience severe pain, redness, or problems with one eye, such as double vision. This could be caused by the lens of the eye moving out of place. Other symptoms may include the appearance of flashes and floaters or, in neglected cases, reduced vision (amblyopia). When examining the back of the eye, doctors may see changes related to nearsightedness, like a myopic disc, myopic crescent, bulging at the back of the eye, or degeneration of the part of the eye responsible for sharp and detailed vision. Other observed features can be a bluish appearance of the eye’s white part (sclera), displaced pupil, and issues with the retina, the layer at the back of the eyeball.

A study by Muralidhar and colleagues found that all patients examined had different levels of nearsightedness due to the shape of the lens, with an average refractive error of -11.07 dioptres. Nearly half of the patients developed glaucoma, a group of eye conditions that damage the optic nerve, and among these patients, half came with high pressure inside their eyes. If the lens moves forward in the eye, this increases the chances of developing such high-eye pressure and a type of glaucoma that causes a sudden buildup of pressure inside the eye. Microspherophakia can often be an isolated condition or may be associated with other diseases. The most commonly found related condition was homocystinuria, which affects the body’s ability to break down certain proteins.

Microspherophakia can be linked with both systemic (affecting the whole body) and local conditions. It’s connected systemically with conditions like Lowe syndrome, Marfan syndrome, Weill-Marchesani syndrome, Alport syndrome, microspherophakia-metaphyseal dysplasia, Cri du chat syndrome, Axenfield-Rieger syndrome, congenital rubella, Peter anomaly, hyperlysinaemia, Klinefelter syndrome, chondrodysplasia punctate, and metaphyseal dysplasia.

Locally, microspherophakia can be associated with conditions affecting the eye, such as:

• Lack of the colored part of the eye (aniridia),
• An unusually large cornea (megalocornea),
• A hole in the optic disc (optic disc colobomata),
• And iridocorneal endothelial syndrome, a group of disorders that affect the front of the eye.

Testing for Microspherophakia

When checking your eyes, the doctor will use a special microscope known as a slit lamp. This tool allows the doctor to examine various parts of the eye, like the clarity of the eye lens, the depth and angle of the front part of the eye, your eye pressure, and your best vision with glasses. The doctor will also use eye drops to dilate (or widen) your pupils to evaluate the back of your eyes. This will help check for features of diseases like glaucoma or any other abnormalities related to nearsightedness and the retina. In a particular eye condition called microspherophakia, doctors use a finding known as the E sign for detection.

Apart from the basic check-up, some additional tests might be needed, like measuring the thickness of your eye lens, and the length of your eye. Doctors may use imaging techniques such as ultrasound biomicroscopy or optical coherence tomography, which take detailed pictures of the front of the eye. These tests can help the doctors better understand why the angle of the eye is closed in some patients. Another technology called iTrace may be used to pinpoint the cause of blurry vision before surgery and predict how you might see after surgery.

In some cases, doctors might find a lower number of cells on the back surface of the cornea (the eye’s clear, front surface), where cells might be thin or sparse. In such situations, a more detailed examination of these cells might be required before any surgical treatment. Also, when checking these aspects of your eye health, the doctor also needs to check the overall body health to rule out any issues that might involve multiple organs or systems in the body.

Treatment Options for Microspherophakia

The way to manage these eye conditions will depend on your specific symptoms. Here’s a simplified version of some of the treatments your doctor might consider:

Lenticular Myopia:
This is a type of nearsightedness that happens when the lens in your eye becomes too thick. Your doctor will check for this and other vision problems. Correcting these issues as soon as possible can help prevent permanent vision loss. You’ll have regular check-ups to see if your vision has changed and if your treatment needs to be adjusted.

Pupillary Block:
Because the lens is round, it can sometimes block the flow of fluid in the eye. This is a common problem, known as pupillary block glaucoma, which can be treated with a type of laser surgery. In an acute attack, medicines called cycloplegics are used to relax the muscles in the eye, which helps relieve the blockage. A drug called mannitol can also help by causing the jelly-like material in your eye to shrink, relieving the blockage.

Angle-Closure Glaucoma:
In this condition, the fluid inside the eye is unable to drain away, causing pressure to build up. This pressure can be controlled with another type of laser surgery, or with eye drops to lower the pressure in the eye. If these treatments aren’t enough, you might need surgery to create a new way for the fluid to drain away.

Subluxated Lens:
In some cases, the small size and shape of the lens can make it slip out of place. This is called lens subluxation, and it requires careful surgery to put the lens back in the right place. Some surgical techniques that have been developed for this type of condition include using a special ring to provide support for the lens. Clear lens extraction, which involves removing the lens completely, can be performed in cases where the lens has touched the cornea, or if the lens has slipped into the cavity behind the eye.

Low Vision:
If your vision problem can’t be completely corrected, you may end up with low vision. This means your vision stays poor even after correction. In this case, you can use low vision aids to help you see better. Low vision might also happen if you have an advanced stage of glaucoma.

Systemic Conditions:
Sometimes, these eye problems can be associated with conditions that affect other parts of the body. Therefore, you might need to see other specialist doctors, such as an orthopedic for bone and muscle conditions, or a cardiologist for heart conditions.

What else can Microspherophakia be?

Microspherophakia, a condition that affects the eyes, can be associated with a range of other conditions. These include:

• Aniridia (absence of the iris)
• Megalocornea (larger than normal cornea)
• Iridocorneal endothelial syndrome (a group of diseases characterized by abnormal corneal endothelium and iris changes)
• High lenticular myopia (nearsightedness related to the eye’s lens)
• Disc coloboma (a gap in parts of the eye)
• Retinal detachment (a serious condition where the retina separates from the back of the eye)

There are also some general health conditions that have been linked to microspherophakia:

• Alport syndrome (a genetic condition affecting the kidneys)
• Weil-Marchesani syndrome (a disorder that affects the body’s connective tissue)
• Homocystinuria (a disorder affecting the processing of certain amino acids)
• Marfan syndrome (a genetic disorder that affects the body’s connective tissue)
• Axenfeld-Rieger syndrome (a disorder affecting the development of the eyes and other parts of the body)
• Metaphyseal dysplasia (a disorder that affects the growth of bones)

What to expect with Microspherophakia

In simpler terms, how serious the condition is can affect the final outcome. A study by Senthil and his colleagues found that more than half of the patients in their study with an eye condition called microspherophakia also developed glaucoma. They stated that an operation called a trabeculectomy had an 86% success rate within the first six months, with a slightly lower success rate of 77% after a year. These results remained consistent for up to seven years. However, they also found that 20% of patients were blind at the time of their first examination, and this increased to 30% later on.

In another study by the same group, they performed this surgery on 29 eyes of 18 patients with this eye condition. They found the chance of complete success was as high as 96% after a year, dropping slightly to 88% after two years. These results again stayed consistent up to seven years later. A different study by Harasymowycz and colleagues reported one patient required a more complex series of procedures after their original trabeculectomy.

Yet another study, this one by Garudadri and his team, looked at 61 eyes with microspherophakia. They found twelve needed a specific type of laser treatment called iridotomy, and 40 required surgery, specifically a trabeculectomy, lensectomy, or a drainage procedure. Out of those, 20 eyes (16%) ended up blind due to glaucoma.

Possible Complications When Diagnosed with Microspherophakia

Microspherophakia is a condition where the lens of the eye is smaller and spherically shaped. This anomaly can lead to serious vision problems. Due to the unique shape of the lens, people with microspherophakia may experience high nearsightedness. The small and spherically shaped lens may be weakly attached and could move out of place or dislocate entirely.

If the lens moves forward, it can come into contact with the cornea, which is the outermost part of the eye. The constant contact may cause a loss of cells or damage in the cornea. This displacement could bring about complications like:

• High Nearsightedness
• Damage to the cornea due to lens contact

On the flip side, if the lens moves backward, it could cause pulling on the vitreous, the jelly-like substance inside the eye, and may lead to the retina separating from the back of the eye. The retina is what makes it possible for us to see, so if it gets detached, it may result in vision loss. Studies reveal that up to 44% of people with microspherophakia experience lens dislocation.

Further issues can arise when an anteriorly misplaced lens causes the front of the eye to become shallow, leading to either a blocked pupil or touches between the lens and the iris.

The potential complications are:

• Retina Detachment due to vitreous pulling
• Pupil Blockage
• Intermittent contact between iris and lens

Glaucoma, a condition that damages the optic nerve, has been found to occur in 44.4 to 51% of cases with microspherophakia. Long-term blockage of the pupil can cause glaucoma, resulting from the formation of peripheral anterior synechiae, a condition where the iris sticks to the cornea or lens, spherophakic lens crowding the trabecular meshwork, the drain of the eye’s fluid, reverse angle-closure glaucoma, or malignant glaucoma. A rare but severe complication is where the glaucoma doesn’t get better, leading to permanent vision loss. In some extreme cases, the eye may need to be removed.

Severe complications can include:

• Glaucoma
• Permanent Vision Loss
• Eye Removal

Recovery from Microspherophakia

After the operation, your doctor may give you medicines such as short-term topical steroids, cycloplegics, and maybe antiglaucoma medications. Cycloplegics are used to temporarily paralyze the muscle that focuses the eye. This is done to reduce eye pain. Antiglaucoma medications help decrease the pressure inside the eye.

You’ll need a follow-up appointment to check for refractive errors, which are common vision problems like nearsightedness, farsightedness, or astigmatism. If the doctor finds any remaining refractive error or you need glasses due to the removal of the eye’s natural lens (a condition called aphakia), they will assist with necessary corrections.

It’s vital to get your intraocular pressure checked each time you visit the doctor for at least six months. Intraocular pressure is the fluid pressure inside your eyes. Monitoring this can help prevent conditions like glaucoma.

Patients with low best-corrected visual acuity (the sharpest, clearest vision achievable, even with glasses or contacts) or limited vision due to damage from glaucoma may need special devices to help improve vision. These are known as low vision assistive devices. The doctor may also discuss any changes you need to make to your daily habits to maintain your eye health.

Preventing Microspherophakia

Patients need to be aware of the importance of regular check-ups. It’s crucial that they understand if they experience any sudden symptoms like redness or pain in the eyes, seeing colored halos or a sudden drop in vision, they should seek medical help right away. They also need to understand the importance of timely eye screenings for issues like refractive error (problems with focusing) and intraocular pressures (pressure in the eyes), and that they might need to change their glasses occasionally.

Depending on their condition on future visits, surgery might be recommended. It’s crucial to reassure patients that microspherophakia, a condition that makes the lens of the eye smaller and more spherical than normal, generally has a good outcome. Furthermore, with timely intervention, one can achieve good vision despite this medical condition.