Lenticonus

What is Lenticonus?

Lenticonus is a condition that affects the eye. It’s a change in the shape of the lens of the eye, which starts to bulge out in a cone shape because the lens covering becomes thinner. This cone-like bulge can happen on either the front (anterior lenticonus) or back (posterior lenticonus) of the lens, and sometimes it can happen on both sides too. The bulge is usually around 2 to 7 millimeters wide.

One condition that is often associated with changes on the front of the lens is Alport syndrome. Initially described in 1972, Alport syndrome is a rare disease passed down through families, affecting kidneys and causing hearing loss.

On the other hand, changes on the back of the lens typically occur in Lowe syndrome, though it’s not always linked to a specific disease most times. A condition often confused with lenticonus is lentiglobus, where the entirety of the lens bulges out in a spherical shape.

People with lenticonus often have near-sightedness (myopia) and irregular eye shape (astigmatism). Other common findings in people with Alport syndrome include early-age eye ring (arcus juvenilis), cloudy lens (cataract), rear eye shape changes (posterior polymorphous corneal dystrophy), and small spots or flecks on the retina.

When managing lenticonus, there are several options. These include glasses, contact lenses, sucking out the lens fluid (lens aspiration), inserting an artificial lens (IOL implantation) along with a procedure in the front part of the eye (anterior vitrectomy).

What Causes Lenticonus?

Anterior lenticonus, a condition where the front part of the natural lens bulges forward, is linked to Alport syndrome. Alport syndrome is a genetic disorder affecting the kidneys, ears, and eyes.

On the other hand, posterior lenticonus, where the back part of the lens bulges backward, usually occurs on its own. But in some cases, it might be associated with Lowe syndrome. Lowe syndrome is a rare genetic disorder that affects the eyes, brain, and kidneys.

Risk Factors and Frequency for Lenticonus

Alport syndrome usually starts showing in kids between 5 and 20 years of age. These kids often have chronic blood in their urine before they turn 40, but this can vary depending on the type of gene mutation they have. As they grow into adults, they might also experience a type of hearing loss that is caused by damage to the inner ear. If the syndrome is passed down through the X chromosome, it will affect men more than women. But if it’s passed down through either of the non-sex chromosomes, it will affect men and women equally and will be just as severe.

• Alport syndrome typically shows up in kids between the ages of 5 and 20.
• These kids often have chronic blood in their urine before they turn 40.
• Some people with Alport syndrome may experience a certain type of hearing loss when they become adults.
• If the syndrome is X-linked genetically, it will affect men more often than women.
• If the syndrome is linked to non-sex chromosomes, it will affect both men and women equally and will be equally severe.

Alport syndrome, a genetic disorder, shows up in around 1 out of every 5000 people. It typically affects both eyes in people who have it. About 85% of the cases are passed down through the X chromosome, 10% through non-sex chromosomes in a form called “autosomal recessive”, and 5% in a form that’s also non-sex chromosome linked, but called “autosomal dominant”.

• Alport syndrome appears in approximately 1 in 5000 people.
• It typically affects both eyes in those who have it.
• About 85% of cases are genetically linked to the X chromosome.
• 10% of cases are passed down through non-sex chromosomes in a form known as “autosomal recessive”.
• 5% of cases are also linked to non-sex chromosomes, but in a form called “autosomal dominant”.

Between 11% and 43% of people with Alport syndrome will experience worsening kidney failure, hearing loss caused by damage to the inner ear, and eye issues. Problems like flecked retinopathy and anterior lenticonus can occur in about 25% of patients with Alport syndrome that’s linked to the X chromosome, but PPCD, another eye problem, is very rare.

• Progressive kidney failure, hearing loss, and eye problems occur in 11% to 43% of people with Alport syndrome.
• Flecked retinopathy and anterior lenticonus are seen in about 25% of patients with X-linked Alport syndrome.
• PPCD, an eye issue, is seen in very few patients.

Signs and Symptoms of Lenticonus

Alport syndrome is a genetic illness that typically results in eye problems, hearing loss, and kidney disease. It is characterized by a defect in the basement membrane collagen, the material that provides structure and strength to tissues and organs. This disorder is most often passed down through families, with 85% of cases being X-linked (passed down through the mother to male children), 10% being autosomal recessive (requires a defect in both parents’ genes), and 5% autosomal dominant (requires a defect in one parent’s genes).

People with Alport syndrome may experience various symptoms including pain, blood in the urine, leakage of protein into the urine, kidney failure (which includes edema and high blood pressure), hearing loss, eye problems such as anterior lenticonus and dot, fleck retinopathy, and posterior polymorphous corneal dystrophy. There can also be other eye abnormalities like posterior lenticonus, cataracts, and retinal detachment.

Eye symptoms can include pain, watering of the eyes, dimmed vision, and sensitivity to light due to corneal erosions. Progressive vision loss can occur due to posterior polymorphous dystrophy. Other symptoms can include lenticular myopia due to anterior lenticonus, astigmatism due to changes in the lens, and reduced visual clarity due to cataracts. Vision loss can also occur due to the macular hole, dot and fleck retinopathy. Macular holes usually don’t respond well to surgery.

Along with these, there are various symptoms that point towards the presence of Alport syndrome:

• A family history of Alport, glomerular haematuria, and no other cause for haematuria
• Bilateral SNHL, dot and fleck retinopathy, and lenticonus
• A lack of type 4 collagen in the glomerular basement membrane

Posterior lenticonus was first reported in 1888. According to some researchers, it’s usually a birth defect and is typically not tied to any systemic disease. It generally presents as an isolated issue. However, in cases where it’s inherited due to autosomal dominant genetics, bilateral involvement is more typical. It’s not common, with a prevalence reported in between 1-4 per 100,000 children.

Posterior lenticonus is also associated with another rare genetic disorder called Lowe syndrome, also known as oculocerebrorenal syndrome. It’s associated with multiple anomalies in males and affects about 1 in every 500,000 people. The substantial manifestations include mental retardation, muscular hypotonia, and renal dysfunction in the form of Fanconi syndrome. There may be ocular issues like posterior lenticonus, congenital cataract, corneal keloid, and infantile glaucoma associated with this syndrome.

Testing for Lenticonus

If you’re being evaluated for eye issues, there are various tests that your doctor may use to assess your condition. One of these is a routine visual acuity examination. This test checks how well you can see by using a Snellen chart, which features different sized letters. Your doctor will check your sight with and without corrective lenses, and through a small hole (pinhole visual acuity).

Your doctor may also perform a subjective refraction test. This helps them to understand how much your eye can bend (or refract) light, determining if you have an astigmatism or a lazy eye (amblyopia). The refraction numbers need to be checked regularly since they can suddenly change, resulting in short-sightedness (myopic shift).

A cycloplegic refraction test is another essential part of your eye exam, which checks your eyes’ focusing power. This is done with your eyes dilated, to also check for lazy eye and to analyze the area around the lenticonus – a condition causing the lens of the eye to bulge.

Your doctor will also check your eye pressure using a method called tonometry to identify if you have an existing condition like glaucoma. An ultrasound B scan can reveal if you have lenticonus, which would appear as bulged-out eye lens material. Imaging tests like Anterior Segment Optical Coherence Tomography (ASOCT) and Ultrasound Biomicroscopy can provide a clearer image of the lens, detecting any abnormalities.

An A-scan and IOL Master, if available in the clinic, are two critical tools that help measure different parts of your eye and calculate the power of an intraocular lens, if needed. A-scan also records if there is an increase in the thickness of your lens.

Patients with lens problems may suffer from neurological issues; therefore, you might be required to undergo a neuroimaging test like an MRI scan, which can reveal any irregularities in the brain.

To diagnose Lowe syndrome, which often presents with eye abnormalities, laboratory tests are critical. These include genetic testing, electromyography, electroencephalography, serology, and urine analysis.

In addition, comprehensive systemic evaluations might be required. These include hearing tests, blood pressure measurements, blood counts, kidney function tests, urine analysis, abdominal ultrasound, renal biopsy, and genetic analysis. This testing comprehensively examines your overall health, aiming to precisely identify any health complications you may have.

Treatment Options for Lenticonus

If you have a family member with Alport syndrome, it’s crucial that you get tested for the condition. This involves undergoing screening on at least two different occasions. Other causes of blood in urine (hematuria) need to be ruled out as well.

Genetic testing and counseling are especially vital if other family members have been found to have mutations linked to this disease.

Alport syndrome treatment usually focuses on slowing the progression of kidney disease and possibly reversing certain eye conditions, and reducing the need for a kidney transplant. It’s also important to manage symptoms related to the eye and hearing.

Medications that inhibit angiotensin, a substance that can constrict blood vessels and cause the kidney to malfunction, can decrease the presence of protein in urine (proteinuria). In severe cases of kidney disease, a kidney transplant may be needed. If Alport syndrome has caused corneal erosions (scrapes on the clear layer at the front of your eye), treatment may involve using a patch, bandage, or applying antibiotic eye drops. In severe cases of corneal disease, a corneal transplant might be needed. If Alport syndrome has led to cataracts or lenticonus (a cone-shaped bulge in the lens of the eye), lens removal and intraocular lens (IOL) implantation could be necessary. It’s important to monitor eye symptoms like fleck retinopathy (spots on the retina) and to use hearing aids for sensorineural hearing loss (SNHL). Macular hole surgery (surgery for a hole in the macula, the part of the eye that helps you see details) can have a poor outcome for these patients.

Regular follow-up visits are very important for individuals with Alport syndrome to manage risk factors and to control symptoms like hypertension, proteinuria, and hematuria throughout their lives. Medications that can be harmful to the ears (ototoxic) should be avoided, and exposure to loud noise should be reduced.

If a patient with Alport syndrome has poor visual acuity (sharpness of vision) due to lenticonus, the removal of the lens and the implantation of an IOL might be necessary. In fact, this procedure might be essential when visual acuity decreases significantly, as maintaining good visual acuity with glasses or contact lenses might become challenging.

IOL placement becomes complex in cases where there is a weakness in the lens’s back, making it difficult to place IOL in its traditional location. In such cases, the IOL should be placed in the sulcus, an alternative eye location.

Pediatric patients may require additional procedures such as Anterior vitrectomy (removing the clear gel between your lens and retina), Pars Plana Vitrectomy (removing the gel in extreme scenarios), and YAG Capsulotomy (Laser treatment for cloudy vision) in order to manage post-cataract surgery inflammation. To reduce swelling after surgery, topical steroids are also applied.

For patients with Lowe syndrome(very rare genetic disorder), treatment for eye conditions like cataracts and lenticonus might start very early in life to prevent the development of permanent lazy eye (amblyopia). These patients might need to wear glasses or contact lenses to aid the eye’s visual development. However, they are at risk of developing irreversible glaucoma, a serious eye condition, and might need surgery. Certain procedures like Goniotomy (a surgical procedure to relieve intraocular pressure), Trabeculectomy (surgical operation which lowers the intraocular pressure), and Tube Shunts might be necessary.

On top of eye care, systemic treatment addresses physical weakness (hypotonia) with early physical intervention. In cases of maladaptive behavior, antipsychotics are helpful. Patients with neurological problems require specific treatment. Renal tubular acidosis (a kidney condition that causes an acid imbalance in the body) is treated with sodium bicarbonate and other alkaline substances. If a person becomes dehydrated, fluids need to be administered intravenously. Lowe syndrome patients also need a vitamin D supplement to prevent rickets (a bones disorder), and doctors need to closely monitor parathyroid hormone (regulates the body’s calcium levels) and calcium levels.

What else can Lenticonus be?

When a patient presents with lenticonus, the doctor has to consider various conditions that could be responsible. This list includes:

• Alport syndrome
• Lowe syndrome
• Lentiglobus
• Thin basement membrane nephropathy
• Leber congenital optic neuropathy
• Zellweger syndrome
• Contagious diseases from birth like rubella or toxoplasmosis
• Congenital myotonic dystrophies
• Congenital myopathy, such as muscle-eye-brain disease
• Joubert syndrome
• Fundus albipunctatus
• Pigmentary retinopathy

By considering all these conditions, an accurate diagnosis can be made.

What to expect with Lenticonus

Ocular (eye) and systemic (body-wide) outlooks are observed in cases of misshapen lens of the eye, medically known as lenticonus. Generally, the vision outlook is positive if lenticonus diagnosis and management are timely. If not addressed quickly, lens rupture can occur and can lead to secondary glaucoma, which can affect vision negatively. In more serious cases where the back area of the lens is damaged, vision success can be improved with proper lens replacement surgery, known as an intraocular lens (IOL) implantation, or an optic capture procedure.

Visual outcomes differ with Lowe syndrome, which is a rare genetic condition causing various health problems, including eye issues. Vision success is determined by factors such as the development of glaucoma, strabismus (eye misalignment), and vision loss in one eye, medically referred to as amblyopia.

The body-wide outlook is considered in patients with a genetic kidney disease called Alport Syndrome. Men with a variant of this syndrome can experience severe kidney damage by age 40. Early renal (kidney) transplantation in Alport patients increases chances for survival and successful graft compared to late transplantation. Severity of kidney damage and the affected nervous system largely governs the quality of life of these patients.

A study by Cheng et al. showed significant vision improvement in 41 eye patients with posterior lenticonus after lens aspiration (removal of the contents of the lens), IOL implantation, and managing amblyopia. About 43% of the patients showed an improvement of two or more grades in visual acuity, meaning clarity of vision, at a check-up six months after surgery. Another study by Lee et al. showed patients with a pre-existing defect in the back of the lens had a better outlook for vision than those who had an opacity, or cloudiness, at the back of the lens.

In all these conditions, early and accurate diagnosis combined with careful management stands to be the best way to ensure improved visual outcomes and prevent kidney failure.

Possible Complications When Diagnosed with Lenticonus

• Strabismus – a condition where the eyes don’t look at the same direction at the same time
• Cataract – a clouding or discoloration of the eye’s lens
• Loss of Central Fixation – inability of the eyes to focus directly on a point or object
• Amblyopia – often called “lazy eye,” a condition where vision does not develop properly in one eye
• Spontaneous rupture of Lenticonus – a sudden break or burst of the lens in the eye causing it to bulge out
• Pigment Dispersion Syndrome – condition where pigment cells of the eye’s iris break loose and float around in the eye
• Hyphema – bleeding or blood collection in the front part of the eye
• Microhyphema – small or microscopic amounts of blood in the front part of the eye

Recovery from Lenticonus

Patients who undergo procedures like lens aspiration, cataract surgery or lens implant (known as IOL implantation), can expect their doctor to prescribe steroids and additional medications to control inflammation caused by the surgery. Doctor will check the patients on the first day after the surgery and again on the 30th day. If patients have any unwanted side effects or if their sight is not as good as before the surgery, they may need to see the doctor more frequently in the first two weeks following their surgery.

It is also recommended that for at least a month after the surgical procedure, patients should avoid getting water splashed in their eyes. It’s also essential for them to understand everything about their care and recovery, so careful and thorough counseling is important.

Preventing Lenticonus

All patients should be fully informed about their eye condition and why they might need surgery. The medical professional should explain how the surgery will be carried out and talk about possible risks and complications that can occur. Additionally, the importance of regular and timely eye check-ups should be stressed.

Patients also need to understand when and how to use their eye medications correctly, as well as the importance of regular meetings with their doctor for check-ups. Alongside this, the doctor should discuss diseases like Alport and Lowe syndrome which are related to the eye conditions. Patients need to understand what these diseases are and when to seek appropriate professional consultation.