The College of Optometrists

Essential Vocab

Tears Debris Discharge Watery - not likely to be infected (so worth putting in your notes if found: 'tears-watery') Sticky - possibly infected Mucusy - possibly infected Oily - possible lid margin disease (blepharitis) Frothing - also associated with posterior blepharitis

Dry Eye is the most common reason to use the slit lamp. 'Cos you may have to discuss topics in the assessments - I am going to talk about dry eye, in my own way -to give you some ideas.

Classic Vocabulary Dry eye is of two types.

Evaporative = where the oily surface layer (secreted by glands of moll and accessory glands) is insufficient to stop enhanced evaporation. =Worse afternoons, with VDU draughts, air-con. etc.

Lachrymal Deficient = where there is not enough tears to form a decent layer over the anterior surface of the eye. Worse on awaking (due to palpebral conjunctiva touches the corneal surface). Gets better during the day (as the tears pickup).

Dry eye is classically quantified by questioning the patient.

The only reliable way of finding if the patient has dry eye - is by asking.

That is because it is such a variable, intermittent problem that gets worse over the years. The best known way of questioning is by using McMonies Questionnaire. This can be looked up in text books or searching the internet.

Basically, all questionnaires work by asking the patient to quantify their symptoms in different situations and different times. This is obviously very subjective (one persons dry eye can be another persons comfortable eye) and also depends on practitioner/ patient interactions.

It is thought that ocular irritation when awaking is possibly due to meibomian insufficiency (mucin is needed to stick the tears to the cornea) -and- General Ocular Irritation during the day or later is possibly due to lachrymal insufficiency.

Measurement

TBUT = put a little drop of fluorescen in to the lachrymal sac. Wait for a few blinks then ask the patient to stare until you see the tear film breaking up. (Fifteen seconds plus=okay, fifteen to ten seconds = moderate dry eye, ten or less seconds - dry)

NITBUT = the same but not using fluorescen - you can watch the film integrity using a keratoscope and wait until the mires distort.

Looking at the tear prism, a height of 0.3mm is normal

Looking at tear quality - debris, oily surface (lid margin disease)

Vision Check = dry eye will reduce the vision slightly, especially with contact lenses.

Bengal Rose/ Lissamine Green test = after instilling wait 2 minutes and examine. Stains dead epithelial cells and mucin strands.

Schirmer test - obsolete test for checking tear volume. Place Schirmer paper into lower lid fornix. Wait 5 minutes, 12mm wetted is normal (with prior anesthesia) 20mm wetted without prior anesthesia.

Newer Ways. And Experience

Experience shows that symptoms don't relate to findings very well. This is partly a problem of the questions and partly due to test methods.

Experience suggests telling people that their eye look 'a bit dry’ - provokes a more accurate response that questioning. (Due to lessening of impulse of patient to 'tell the practitioner what s/he wants to hear'!).

note:[[The eye is similar to joints in several, they are made from modified connective tissue and bathed in nutritious fluids (tears and synovial fluid). They heal slowly and less well with age. If the fluid is not doing its job - then irritations will happen. Any irritation will cause inflammation. We all know what an inflamed joint or tendon feels like! So look for signs of inflammation and regard the eye as a unit - not just a collection of tears, corneas etc.

So it is simply not accurate to call it 'dry eye' any more than you would say a dry knee joint. Chronic Ocular Irritation is much more accurate.]]

Expect signs of inflamed eyelids. Dry eye awakes the immune system and causes inflammation. So in chronic dry eye the eye will be slightly injected, the conjunctiva will be slightly chemosed.

Modern Tests

Lid Wiper Epitheliopathy. (Due to lower lid inner-margin being irritated by dry eyeball when blinking) = Looking for fluorescen staining on the inner lower lid margin (pull lower lid back to see – it is often nasal) = this 'wiper' stain is indicative of dry eye due to lid irritation from blinking over a dry eye.

Looking for a changing tear prism with different gazes. This is my own contribution and I call it Stevens Sign 1 (it was called Palfi's sign, which is my internet name). The idea is simple.

It is easiest seen after fluorescen is instilled. You will need medium magnification and blue filter.

Focus and note the tear prism forming at the lower eyelid junction. Now you get the patient to look up.

If the tear prism drops at all - a degree of dry eye is noted.

In more severe dry eye the prism will drop behind the lower lid and disappear.

This is because the lid pouts away from the eyeball on up gazing. I grade it into 3 – mild drop(1), medium(2), hidden behind lid margin (3)(contra-indicates contact lenses)

The theory behind this is simply that the mild inflammation will increase the lid width (oedema) causing it to be less elastic and not follow the globe so well. This simple test works very well and combined with the lid margin exam will help you to check for and quantify dry eye easily. If the lid is thickened then when the patient looks to the left and then to the right the lid will also not keep in touch with the eyeball and the tear prism will diminish in height.

Also, and important sign is the appearance of the lid margins. This is also my contribution and I call it Stevens Sign 2.

1) A lid margin in non-dry eye will be slightly domed, it will be pink and smooth, with no telangeictasia or induration.

2) A lid margin in dry eye will show increasing signs of inflammation in increasing dry eye. The greater the problem - the greater the lid margin signs.

These are - the lid margin will get increasingly flattened and then concave, it will be uneven in colour, with pale and red patches. These patches will match its uneven (tylosis) and roughened surface. There will be areas of telangeictasia and patches of induration.

After years of chronic dry eye the lid margin will become damaged and peel away from contact with the globe and it will take on a thickened, rounded shape.

2A) from the above it can easily be seen that - these are the description of blepharitis (and it is true that dry eye and blepharitis go together)

3) How do you check? Turn the slit horizontal. Look at the margins with medium magnification. Check the margin shape by indirect illumination.

Get the px to look up, Bounce the slit beam from the lower limbus so that it reflects back and down onto the lid margin.

Slide the beam downwards from the limbus towards the lower lid margin and the beam will show up any margin contours easily. Do this with a small 3mm beam, white and also green filters.

Conjuctival folds and stain.

Bulbar stain is graded into 9 parts. 9/9 is very stained. The eye is divided into 3 vertical strips, nasal, central, and temporal = each is given 3 marks out of 3. Add the total. Folds are thought to be due to dry lids dragging over loose conjunctiva.

Look for lid abnormalities Poor closure, poor punctum positioning,

-steve

I'm not a student but found this info very useful - will look for your signs!