What does it mean to have dry eyes and why does my eye doctor always tell me that I have dry eye when they are actually watery? 

WHAT IS DRY EYE?:

Dry eye is one of the most common causes of sensitive eyes.  In Australia, 7% of adults have some degree of dry eye, and that number increases dramatically to 57% over the age of 50 (Blue Mountains Eye Study, 2003).  Dry eye symptoms are more frequent in women, especially as we get older. 

The surface of the eye is covered in a really delicate layer of tears.  These tears are important for proper functioning of our eyes, especially in terms of comfort and vision, but also in terms of protection and nutrition. 

The tear film is made up of 2 main layers.  An outer lipid or oily layer and an inner aqueous or watery layer.  The lipid layer is mostly produced by the oil glands in our eye lids.  This layer stops the tears from evaporating so easily, so it helps them to stay smooth and in the eye.  The aqueous layer is made up of water, salts or electrolytes like sodium, potassium and chloride, and proteins.  The aqueous layer also contains mucin or mucous that helps the tears to stick in our eyes, spread out properly and have some barrier function.  

Tear production, evaporation, absorption and drainage all result in a dynamic balance of our tear film.  When this balance is off, and we don’t have enough good quality tears present to keep our eyes comfortable and functioning well, we have dry eye.  Most of us will experience dry eye from time to time and it might present with symptoms like redness, irritation, foreign body sensation (feeling like sand or gravel), tired eyes, itchy sticky or watery eyes and fluctuation of vision.  Sometimes dry eye is outright painful. 

It might seem weird that dry eyes can be watery.  It’s because people with dry eyes usually have poor quality tears, causing little spots of (usually temporary) damage that make the eyes feel irritated.  When our eyes are irritated, we produce “reflex” tears.  Reflex tears are not the ones that should be in our eyes all the time, keeping our eyes healthy.  Reflex tears are the ones that we get when for example we poke ourselves in the eye.  Reflex tears are a protective mechanism and make peoples eyes water even though they are dry. 

When dry eye becomes more problematic, so it’s lasting for a long time and really having an impact, we refer to it as dry eye syndrome. 

A technical definition of dry eye syndrome, developed by the tear film and ocular surface society dry eye workshop II (DEWS II) based on evidence and mostly highlighting the fact that most people with dry eye have more than one reason to have it is: 

Dry eye is a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles. 

This means that most people with dry eye have more than one reason to have it, that eyes with dry eye lose the ability to maintain their own healthy environment, that dry eye is uncomfortable, and that causes include things like poor tear quality, inflammation and altered sensation in the eyes.   

Dry eye syndrome is common, affecting from 5% to 33% of adult populations worldwide.  A big study in Australia called the Blue Mountains Eye Study found that 57% of Australians over the age of 50 have some symptoms of dry eye.  There is an increased prevalence among adult women and people of Asian backgrounds. 

There is no “cure” for dry eye syndrome…. we usually can’t just make it go away.  It’s all about management. With the right knowledge, strategy and commitment the impact of dry eye can be massively reduced.   

CAUSES OF DRY EYE:

There are 2 main causes of dry eye syndrome, but actually most people (90%) have a mixture of both.  The main categories are aqueous deficient and evaporative dry eye. 

Aqueous deficient dry eye is when you don’t have enough of the middle, watery layer of tears.  This is more common as we get older, especially for women and often relates to hormonal changes.  Other causes can include lack of sensation that might occur from previous eye surgeries, infections or trauma or medical conditions like diabetes or nerve palsies.  Other common causes of aqueous deficient dry eye are medications – there are many that can have an effect but antihistamines, blood pressure medications and anti-depressants are common.  Lastly, autoimmune and inflammatory conditions can affect the aqueous layer.  Sjogren’s syndrome is a common one, where antibodies produced by your body attack the delicate glands in the body that produce both saliva and tears.  Other examples include rheumatoid arthritis and lupus, but there are many autoimmune conditions that can contribute to aqueous deficiency dry eye. 

Evaporative dry eye is often caused by environmental conditions.  This type of dry eye can affect anybody, but is probably more common in younger people, especially as we are all on our screens so much.  Factors in the environment that might increase evaporation include low humidity, hot weather, heating, wind or air conditioning.  Poor blink can contribute to this.  Our tears naturally evaporate in between blinks – it’s why we blink about every 3 seconds to keep our eyes nice and fresh.  When we’re concentrating, especially on screens we blink less often.  Maybe only every 10 or 12 seconds, so this can have a big effect.  Also, some people don’t blink fully.  This is hard to control, but if you only blink to 2/3rds closure, the bottom half of your eye will be exposed to tear evaporation.  Some people don’t close their eyes fully at night and this can make the problem even worse.   

A really common cause of evaporative dry eye relates to the eye lids.  Inflammation in the eyelids contributes to dry eye in more than half of people.  Each eyelid has about 25 tiny oil glands right in the margins, behind the lashes.  These glands produce the delicate outer lipid layer of the tear film.  In many people, often related to skin type (people prone to redness or roseacea especially) or poor blink, these glands can become blocked up with the oil that they produce.  The oil then solidifies, becomes poor quality, attracts bacteria and goes rancid, hence causing more inflammation and reducing the quality of the tear film. 

Another common cause of evaporative dry eye is contact lens wear.  Contacts can be excellent tools to improve vision without glasses, but they do disrupt the normal processes of tear replacement and can lead to evaporation. 

So, these are the common causes of dry eye.  In real life, almost everyone has a combination of aqueous deficiency and evaporative dry eye, what we call “mixed” dry eye syndrome.  It’s important that we consider the cause of dry eye in each particular situation as it helps us to guide management and make the most difference. 

MANAGEMENT OF DRY EYE:

• Management of dry eye is multifactorial, meaning that there is usually more than 1 thing that you will need to do. 
• Management is about reducing the impact of dry eye. Unfortunately, treatment rarely makes dry eye go away altogether, although it can dramatically reduce the symptoms. 

The types of things that we consider are: 

• Education  
• Dietary and Lifestyle Modification 
• Eyelid cleansing 
• Lubrication (eye drops, gels and ointments) 
• Environmental modifications 
• Inserting special plugs into the tear ducts 
• Medications (such as prescription anti-inflammatory eye drops) 
• Specialised eyelid treatments 

We can’t really cover too much on management in this blog, but do use this as a starting point.  Do your research and please be sure to see your eye health professional for a diagnosis and management plan if you think you might have dry eye.  We definitely won’t recommend any specific medications here – your eye health practitioner will need to examine your eyes first.  Remember that information in this blog does not constitute medical advice.  We do believe though that education is the most important factor when it comes to dry eye management … if you can nail that then you will be well on the path to improvement. 

CAN I STILL WEAR MAKE UP IF I HAVE DRY EYE?

YES!!! This is what OKKIYO is all about.  Here at OKKIYO we know that sometimes it’s our beauty routine and/or makeup that makes us feel powerful, ready and awake and we want everybody to be able to feel those things, even if your eyes are dry or irritated or you're not feeling so great.  See this blog here which covers 7 tips for wearing eye make up if you have sensitive eyes and note that all of these tips apply if you have been diagnosed or even suspect that you have dry eye.  Please do remember to see your eye health professional for a diagnosis and specific management plan if you have sensitive eyes.  You might like to try PRIORITEYES mascara that has been specifically designed by Australian Ophthalmologist and founder of OKKIYO Dr Jacqueline Beltz for people with dry or sensitive eyes.  This mascara underwent lab (but not on animals!) testing and even a clinical trial in which people with sensitive eyes wore the mascara every day for 28 days before answering a series of questions and having their eyes examined by an independent (i.e. not Jacqui!) ophthalmologist to make sure that PRIORITEYES does not increase irritation.  Of course, no product would be expected to be perfect for everybody so definitely discontinue use and see your eye health professional if you do have a reaction! 

We hope that you enjoy PRIORITEYES mascara as much as Jacqui enjoyed developing it!