Assessment
Dry Eye is not as simple as a lack of water in the eyes. Dry eye is a multifactorial disease of the ocular surface characterised 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.
When you come to Barot Vision Care we spend a lot of time assessing your eyes to try to identify the root causes of your symptoms. We use the latest techniques and technology to assess the composition of your tears and the status of the tear producing structures of the eye. We look for signs of ocular inflammation.
Assessment Techniques
As part of every ocular assessment, the Slit-lamp is a high magnification microscope used to look for any abnormalities at the front of the eye whether or not it is related to dry eye. This is where we look for signs of blepharitis, demodex and eye lid abnormalities.
To help provide information on the health of the surface of the eye, certain dyes (such as Fluorescein and Lissamine Green) may be used to look for any cellular distress or damage caused by dry eye.
We also use this to look at the tear break up time and tear prism height of the tear film.
This is an old but effective test for aqueous deficiency (lack of production of the watery part of the tears).
The test records how much fluid is produced when a small piece of paper is inserted in between the lower lid and the eye.
It takes around 5 minutes to perform and if the results are normal this rules out aqueous deficient dry eye.
This is the only clinic technique that can provide information on the state of your meibomian glands. By using infrared technology, the structure of the glands can be looked at accurately with no interference from the surrounding anatomy.
We have around 20-30 glands on the lower eye lids and 30-40 on the upper eye lids. The imaging allows us to see whether the glands are structurally normal, dilated, shortened or atrophied from chronic obstruction.
Meibography is a very important test that tells us about the structure of the glands and helps us to grade the level of meibomian gland dysfunction. It also helps us to identify the presence of any gland atrophy. It does not however, show us what is produced by the glands. For this reason, we perform manual gland expression as part of the initial assessment to help us with the correct diagnosis. The oily substance that it produced by the meibomian glands is called ‘Meibum’. When we manually express the glands, we can see the type and quality of meibum produced by each gland in both the upper and lower eyelids.
Treatment
After we have determined the type and cause of your dry eyes we will formulate a suitable treatment plan for you. We will recommend a suitable 'in house' treatment that is offered at the clinic. Often it is necessary to do some treatments at home in between visits. Depending on the nature of your dry eye we may also prescribe a course of medication.
Some treatments focus on reversing or managing a condition or factor that's causing your dry eyes. Other treatments can improve your tear quality or stop your tears from quickly draining away from your eyes.
Range of Treatments
In order to better understand how the glands are functioning, it is important to know what the meibum quality is like. For this reason, we perform gland expression at every initial visit as part of the diagnostic routine.
Regular meibomian gland expression is also important for continual treatment the blocked glands.
We gently heat the lids before expression is performed. This helps to open up the gland openings and to soften the meibum making it easier to express. We then gently squeeze each gland to express the blocked material. Meibomian gland expression is also performed straight after each Intense Pulsed Light treatment.
After the treatment we may give some medical treatment and home exercises to help keep the glands functioning.
Intense Pulsed Light – as the name suggests is a pulse of intense light that is applied to the skin around the eyes. The light used is selected at a specific wavelength and strength. When applied to the surface of the skin, the light is absorbed by the haemoglobin of the abnormal vessels which destroys them by thrombosis. The major source of inflammation affecting the eye lids is then reduced or removed. Once this occurs, the number of inflammatory markers reaching the glands reduces. This then provides a better environment for the meibomian glands to function.
For some people the bacteria that naturally live around the eye become over active. When they are over-active they produce toxins that irritate the lids and the eye, causing dry eye. They also produce crusting usually on the lashes themselves.
Removing all the debris is key to eliminating this problem known as Blepharitis.
The Blephex machine is like going to see the dental hygienist but for eyes. It’s spinning head removes all of the debris from the lids and lashes like a super deep clean. This allows the patient to continue lid hygiene at home and to successfully eliminate blepharitis and reduce their dry eye symptoms.
Most contact lenses can be quite demanding on the tear film. Soft lenses can lose water content over time, when this happens moisture is drawn from the ocular surface. This is why people with dry eyes find that their wearing time is less than expected. A good tear volume is needed to keep the lens hydrated which makes lens wear more comfortable for longer. Some lenses have differing water contents so will have differing dry effects. Newer lens materials have been shown to have better moisture retaining properties.
Rigid gas permeable lenses work by forming a tear layer between the lens and the cornea. This tear layer is needed for the correct fitting of the lenses and to provide optimal visual correction. If insufficient, the lens will rest too much onto the cornea and can cause too much friction on the surface. At the same time, poor vision correction occurs without a decent tear layer. It is therefore even more important that there is an adequate amount of tears for rigid gas permeable lens wear.