Dry eye tests using photography

Dry eye tests using photography


Detecting the causes of Dry Eye Disease

How to diagnose DED

I like solving mysteries!  Why do eyes feel dry?  The answer is straight forward.   It is either a decrease in tear film lubricity or poor tear film coating caused by?  Below we will see the factors that cause it. Over the last decade our insights have built on the work of many giants in our area (Too numerous to mention here).  Using a combination of the best thinking and questioning what we were missing which was ‘hiding  in plain sight?’   We answered the non intuitive questions why dry eye tests like Schrimmer and TBUT etc are only helpful and not diagnostic.  

Our understanding of dry eye disorders was aided by the development of high contrast corneal fluorescein photography. It allowed us to see the subtle corneal changes as well as the dynamics of the lid and tear film. Video with slow motion permitted analysis which we share below. 

Photography has helped us diagnosis dry eye disorders and also evaluate if treatment works. I believe it represents an improvement over all tests.   Many of my DED patients had ‘undetectable’ findings. In fact many seem to tear. It was easier to tell our patients “to stop on the way out for a sample drop.”  When desperate we ordered immunomodulators and even plugs.  

We all have favorites but could rarely discern what was in them. Indeed, most manufacturers sell by the Pepsi-Coke premise of slick advertising.  

My goal was to find out why patients have DED and uncover the underling cause. That is the best way to fix anything. Based on our findings we are developed new  drops to treat some of the underlying causes. 

Tear film in motion

Static pictures are useful in DED, but along with video shows you the complete picture of the tear coating during the blink.  Ex. If you recall the gallop of horses was painted incorrectly until movies. Note the actual gallop.

Advantages of photography

A photo is better than a word description to document your findings. It allows you to track changes with treatment and to engage the patient when you show your patients their own images.

Photos plus video will shows you the whole picture of tear film coating during the entire cycle. 

Our specially advanced fluorescein slit lamp camera is now commercially available and gives detail that you would miss with a normal slit lamp. 

 Below is a comparison of your slit lamp blue light to what the new system can visualize. It allows you to see subtle punctate stain as well as tear coating and dynamics. 

Reasons for punctate stain

The advanced fluorescein LED exciter and barrier filter show the subtlest punctate stain which is the most consistent finding in DED.

We have evolved from the NEI classification that quantifies it, to looking for the reasons of the punctate stain. Currently we functionally classify tear film failure beyond its liquid components:

  1. excessive mechanical rub from margins or conjunctiva 
  2. blink abnormalities
  3. elevated limbal areas that impair tear film coatings
  4. conjunctival disorders of allergy, blepharitis, follicular conjunctivitis, concretions, scarring   
  5. neurotrophic and toxic keratitis. 
Punctate corneal stain
Punctate corneal stain

Tear film flow

Video of the fluorescein tear film and its coating can be diagnostic. The blink is dynamic and a still photo does not demonstrate the dynamics of the coating. The tear film on the upper cornea does not coat the bottom half.   Note the vertical punctate stain and 3 black streaks not coated by fluorescein.

Vertical streak seen in photograph
Vertical streak seen in photograph

Are treatments working?

The best way to follow treatment is by comparing past and present fluorescein images. If no improvement try another therapy!

3 week comparison of treatment
3 week comparison of treatment

Slow motion videos

This shows instant replay slow motion:

Other explanations beyond ‘tear film evaporation or defective tear films’

Note the lower corneal punctate stain and the lack of coating the lower 1/3. Tear film evaporation is less significant since it never got coated.

Direct observation of the tear film

PRE CORNEAL tear film
PRE CORNEAL tear film

Observe that by using retroflection you can see the actual PRECORNEAL TEAR FILM.  With careful high power observation you can see meibian particles, oil, globular mucus and even a sense of thickness. A video below shows the tear film rising after the blink. 

Click any photo to enlarge it

Meibum and microsphericles particles

Renewed attention is being given this area. Use this link for more information on meibomian examinations  

Dr. Clifford Terry