16 IOP Measurement and Anterior Segment

With respect to your anterior segment examination, I want to emphasize a few key points.  Dr. King has provided you with information about anterior segment findings in V644 – Ocular Disease I.  It is expected that you are familiar with that information, and can apply it clinically.  You can read more about common anterior segment and posterior segment findings here

After IOP measurement, quickly scan the cornea for defects

Epithelial defects caused by IOP measurement should be easily seen with a quick 10X parallelepiped scan of the cornea with cobalt blue filter.

Learn to hold open eyelids for both IOP measurement and for anterior and posterior segment examination

This technique is critical if the patient is sensitive to objects coming close to their eyes (as in IOP measurement) or if they are sensitive to light.  You can do so with your fingers, or with a sterile applicator.  Learn to master one or both techniques.

Know which alternative IOP measurement techniques you’ll use if Goldmann applanation tonometry (GAT) doesn’t work

Not everyone responds well to GAT.  If you can’t get a GAT measurement, know where you’re going next in terms of technique, and perform that technique as appropriate.

Perform a parallelepiped scan of cornea at 10X magnification

Perform a scan of the entire eye at 10X magnification, using 16X (or greater) for details.  Performing this scan at 16X magnification often results in missing pertinent findings.

Master the optic section

Failure to do so can result in inability to correctly grade angles and localize lesions to their appropriate layer of the cornea and/or lens.  A good optic section allows you to see epithelium and endothelium as a whiter line on either side of your section.  In a similar manner, layers become apparent in the lens with a correctly set up optic section.

The optic section scan of the cornea is not commonly performed (it shows up in V552 and V653 because it shows up on Part III of boards).  Instead, use your parallelepiped scan of the cornea to identify corneal abnormalities when present, and then use the optic section to answer the question, “in what layer is this finding located?”  Knowing the depth of a finding will help you to identify (or rule out) a particular diagnosis.

Retro-Illumination

Retro-illumination is generally reserved for after dilation, although if you see something that makes you do it earlier, you should do it earlier (what might that something be?).

Lens Examination

Your examination of the lens body and anterior lens capsule is generally deferred until dilation.  There’s just so much more to see when the patient is dilated.  However, it doesn’t hurt to look prior to dilation, and, of course, if the patient declines dilation.