How to use an Ophthalmoscope

Two weeks ago I asked for tips using a direct ophthalmoscope and since then, I have come to learn that the two most ubiquitous tips in this regard are

a) practice makes perfect; and

b) ophthalmoscopy is hard.

Both of these are true, and thank you if you gave me those tips, because they made me feel less desolate. However, after the resolution of my ophthalmology rotation, I do have a few tips to offer, because it really is difficult, and practice really does make perfect.

1. Have your own eyes looked at

This is two-fold. If, unlike me, you have perfect eyes, you may never have had to keep your eyes open for a long period of time while somebody shines a bright light in them, and so your empathy with what can at times be an uncomfortable examination may be lacking.

Additionally, if you do have a refractive error, it is important to know what it is, because you will not start the ophthalmoscope at 0, but at your reading. So someone with a -4 error will begin on -4 (the red side) and vice versa. Note that astigmatism does affect this reading as well and you will most likely have to play around with the dial to find a good focus length for you.

2. Inspect the inspector

I once spent a whole day feeling miserable for not being able to see through the ‘scope, until I realised that the actual lens was blurry! Hospital-issue ophthalmoscopes that are used by everyone may often be grimy. Clean the viewer on both sides to ensure you don’t get a falsely-blurry image.

3. Dilate the patient’s eyes

Many people refuse to dilate eyes because – because I don’t know? Because they’re stubborn? Because they feel guilty if anything is easy? The odd patient cannot be dilated for whatever reason, and particularly fair-skinned and fair-haired patients may be easy to visualise undilated, but in general it is so much easier to look through dilated pupils. If given a choice, choose YES. Note that some patients dilate with one drop, while some might need more drops or more time. And of course, patients with posterior synechiae might not dilate at all.

4. Explain to the patient

So many times I have fallen into the trap of explaining to a patient while I am already staring into their eyes. Take a minute BEFORE hand to explain to the patient that it may be a little uncomfortable, but if they co-operate, it will be over quickly. The patient needs to look at a distant object to prevent accommodation, but don’t tell them to “look at that big wall over there” – the target is too big and their eyes will roam.

5. Dim the lights

Making the room COMPLETELY dark is awkward, because you can’t find your way and patients with very poor vision get quite nervous. Also, reflections of the light also become a lot more annoying in the complete absence of other light.

6.Position the patient

I found that moving the patient onto a stool was easier than examining them in the massive ophthalmological chair which makes it near impossible to get past their knees. It is also useful to have them a little lower than you, so that you have the leverage to move around. Lastly, patients tend to want to look up when you look in their eyes, or sometimes we tend to tilt their chin upwards – don’t! It does funny things to their eye movements and completely disorients what you see.

7. Hold the ophthalmoscope correctly

It may be comfortable holding it like an ice cream cone, but it is not practical. Have you index finger on the dial from the get go, so that you can dial to focus with comfort. It is useful to practise these maneuvers at home as well, because it can be uncomfortable.

8. Approach from the lateral side

After viewing the red reflexes from the front, I like to take a more side-ways angled approach. This makes it more difficult for the patient to accidentally look at the light, and makes the corneal light reflex less likely to reflect straight back at you. The angle also means you are looking nasally, where you will find the optic disk more easily.

9. Right eye, right hand, right eye

People get confused by this, but always remember that the last thing you (or the patient) want to do is to kiss them!

10. Get up close and personal

Unless you are using a PanOptic, you really need to get right up in the patient’s face. Seriously. Just do it.

11. Play with the dials

You may have corrected for your refractive error but your patient may still have one. If everything seems fuzzy, try playing around with the dials to get a good focus. You might also change to the polarised light or to the red-free light (the latter will make all red structures appear black).

 12. And NOW you can examine the fundus

Once you’re in, the hard part is done. Your landmark is the optic disk – which will be slightly paler than the surroundings in a healthy eye. If you struggle: the optic disk is where the major vessels combine. Remember that you will need to move around (yourself and the opthalmoscope, not just your eyeballs) and that the image you will see with a direct ophthalmoscope will not give you an entire retinal image like in the textbooks (realising that was a turning point for me). HINT: Don’t tilt your head into the visual axis of the other eye, otherwise they will accommodate and focus on you.

I don’t need to tell you what to look for in the fundus – those are textbook matters. Stanford has a nice page about it here and there is a really nice legally-free ophthal e-book here.

Did I forget any hints? Feel free to leave them in the comments if I did!