What Are Double Eyelashes?
Double eyelash is a rare condition of having two rows of eyelashes in an eyelid.
It is medically termed Distichiasis and can affect both eyes.
An extra row of eyelashes is present on either the upper or lower eyelids (or both).
The meibomian gland is where the double eyelashes arise on each eyelid.
They are oil-producing glands that help lubricate your eyes.
It coats tears, which stops the eyes from drying up too quickly.
Common signs and symptoms of double eyelashes include:
- Conjunctivitis (swelling, redness, irritation in eyes)
- Ptosis (droopy eyelids)
- Corneal ulcer (an open sore on your cornea)
- Sensitivity to light (photophobia)
- Styes (small, painful bumps on your eyelid)
- Corneal scarring (deep scratches in your cornea)
- Severe eye pain
- Vision loss
What Does Distichiasis Look Like?
The second row of lashes is typically lighter, shorter, and thinner than the first.
They can be either a whole set of eyelashes or one or two lashes on each eyelid.
Usually, lashes grow at the dry outer edge of the eyelid, but the extra lashes grow from the wet inner edge of the eyelid.
How Common Is Distichiasis?
Estimates suggest that about 1 in 10,000 people have double eyelashes.
What Is The Difference Between Distichiasis And Trichiasis?
In distichiasis, an extra row of eyelashes is present.
In trichiasis, thereโs only one row of eyelashes, but instead of curving upwards, they curve downwards toward the cornea.
Unlike distichiasis, it is only acquired - in some cases, the cause is unknown, while in other it occurs secondary to conditions like Stevens-Johnson syndrome (SJS) or chemical burns.
| Distichiasis | Trichiasis | |
| What it is | Extra row of eyelashes | Only one row - lashes curve inward |
| Acquired or inherited | Both | Acquired |
| Causes | FOX gene mutations, certain medications, contact lenses | Secondary to other inflammatory conditions |
| Treatment | Epilation, electrolysis, and cryotherapy | Epilation, electrolysis, and cryotherapy |
Why Does It Happen?
The two main ways distichiasis can happen are:
- Congenital
- Acquired
Congenital distichiasis is when the disorder is present at birth.
Acquired distichiasis can be developed later in life.
Congenital Distichiasis
Congenital distichiasis happens if epithelial cells of your eyes develop incorrectly or modify into a pilosebaceous unit.
The pilosebaceous unit, comprising the hair follicle, hair shaft, and sebaceous gland, makes the extra row of eyelashes.
Congenital distichiasis occurs when there is a gene mutation in FOXC2 (forkhead box protein C2) during conception.ย
The FOXC2 gene is involved in other inherited conditions besides distichiasis.
Acquired Distichiasis
Acquired distichiasis develops when eyelids get injured or inflamed.
Here are some factors or conditions causing acquired distichiasis:
- Exposure to chemicals
- Blepharitis - Inflammation of oil glands in eyelids
- Meibomian gland dysfunction (MGD) - A group of eyelid disorders
- Ocular cicatricial pemphigoid (OCP) - A severe form of conjunctivitis that causes scarring in the eyes, mouth, and throat
- SJS - A skin disorder characterized by rashes, blisters, and shedding off dead skin cells.
What Is Lymphedema Distichiasis Syndrome?
Lymphedema is a condition characterized by swelling of the legs due to the accumulation of fluid between the skin and muscles.
When a person has both lymphedema and distichiasis, it is called lymphedema distichiasis syndrome.
Some conditions that can co-occur with this syndrome include:
- Drooping eyelids or ptosis
- Curved spine or scoliosis
- Cleft palate
Genetics of Double Eyelashes
Double eyelashes can occur due to FOXC2 gene mutation.
The FOX (forkhead box) gene family consists of 21,418 protein-coding genes.
The FOX genome produces proteins called transcription factors that control how genes work.
Some transcription factors of the fox gene family are A1, A2, B1, C1, C2, D1, etc.
They play a role in cell aging, growth, and death, maintaining metabolism, and the development of different organs. The FOXC2 gene turns on and off many other genes during fetal development.
Is Distichiasis Due To A Genetic Mutation?
A rare genetic mutation of the FOXC2 gene on chromosome 16 causes distichiasis.
This mutation turns on excess transcription to cause a double row of lashes during prenatal development.
It can lead to droopy eyelids and yellowish nails.
What Are The Risk Factors For Developing Double Eyelashes?
Family History
Genetics is a prominent risk factor in developing congenital distichiasis.
You are more likely to inherit the condition if any of your parents have double eyelashes.
Age
Older people are more likely to develop eyelid disorders like ocular cicatricial pemphigoid (OCP) and meibomian gland dysfunction (MGD).
Sex At Birth
Females are more susceptible than males since they develop OCP quickly.
Eyelid Inflammation
Seborrheic dermatitis or dandruff on the scalp and brows increase the chance of developing swollen eyelids.ย
Other risk factors include allergies, bacterial infections, clogged oil glands on your eyelids, and eyelash mites or lice.
Certain Medications
Meibomian gland dysfunction (MGD) is more likely to occur in people who take glaucoma medication.
Stevens-Johnson syndrome (SJS) can affect people who take painkillers for gout, seizures, infections, and mental illness.
Lack Of Immunity
Immune-compromised people are at higher risk of developing eyelid disorders.
Use Of Contact Lenses
Contact lenses can irritate your eyes, which can lead to inflammation of the eyelids.
Is Double Eyelashes Dangerous?
Double eyelashes associated with FOXC2 gene mutation can be dangerous as it is associated with other inherited conditions like lymphedema distichiasis syndrome (LDS).
A mutation in the FOXC2 gene causes an increased risk of congestive heart failure (supply of fluid to the heart instead of blood).
Congestive heart failure causes shortness of breath, leading to sudden death.
How Do You Know If You Have Lymphedema Distichiasis Syndrome?
This condition is usually confirmed by a genetic test in a clinical setting.
Symptoms that could indicate LDS include:
- Swelling of legs due to fluid accumulation
- Double eyelashes
- Varicose veins (in some cases)
How Is Distichiasis Treated?
You do not need medication if you are asymptomatic.
If you experience any symptoms, treatment will emphasize subsiding them.
It could also require removing the excess eyelashes.
The number of extra lashes and your symptoms will determine the best treatment.
Hydrating Eye Drops
Lubricating eye drops hydrate the eyes and can ease acute eye irritation.
It works by shielding the cornea from excessive lashes so as not to irritate.
Smooth Contact Lenses
Soft contact lenses offer a layer of defense similar to lubrication.
Ensure you use contact lenses correctly to avoid any problems.ย
Epilation
An epilator is used to remove the extra lashes.ย
It pulls out extra lashes physically from the eyelid.
It is a temporary solution because the lashes often grow back in two to three weeks.
People with few extra lashes can undergo epilation.
Cryotherapy
Cryotherapy detaches eyelash follicles from eyelids using extremely cold temperatures.
Although having few side effects, it has long-lasting results.
Cryotherapy may cause side effects like:
- Loss of nearby eyelashes
- Thinning of the eyelid edge
- Minor scarring of the eyelid
- Eyelid depigmentation
Electrolysis
Electrolysis is preferable to epilation for eliminating a few eyelashes.
A needle with a short-wave frequency is injected into the eyelash follicle.
During this process, the follicle is let loose from the eyelid.
Lid Splitting
One kind of eye surgery is lid splitting.
The eyelash follicles are visible when eyelids are split open.
Individually, the excess eyelashes are taken out.
Lid splitting is occasionally combined with electrolysis or cryotherapy.
Argon Laser Thermoablation
The lash follicles are repeatedly burned with an argon laser, removing the follicles.
During the procedure, you can feel uncomfortable and have an increased tear flow.ย
Other FAQs About Double Eyelashes
What Is The Difference Between Distichiasis And Districhiasis?
Distichiasis is double rows of eyelashes, and districhiasis is three rows of eyelashes.
What Is Ectopic Lashes?
Ectopic lashes or ectopic cilia are lashes that grow from abnormal places or in abnormal directions.
For example, lashes may grow from the conjunctiva or the pink part of the eye.
Summary: Double Eyelashes - Why Does It Happen?
Double eyelashes or Distichiasis is a condition where an extra row of eyelashes is present.
It can be congenital distichiasis or acquired distichiasis, depending upon the cause.
A mutation in the FOXC2 gene causes congenital distichiasis.
The FOXC2 gene mutation leads to other inherited conditions like lymphedema-distichiasis syndrome (LDS) and congestive heart failure.
People with a family history of double eyelashes, eyelid inflammation, painkiller medications, and poor immunity are at high risk of developing the condition.
Double eyelashes is treated by argon laser thermoablation, cryotherapy, epilation, lid splitting, etc.
