Examination of anterior segment of the eye involves examination by:
- Diffuse illumination
- Direct focal illumination
- Specular reflection
- Transillumination or Retro-illumination
- Indirect lateral illumination
- Sclerotic scatter
The steps involved in anterior segment examination may be summarized as:
- Introduction
- Visual acuity checked grossly
- Torch: General appearance, HZO marks, facial asymmetry, iris, pupil size.
- Check Setting. There should be:
- Low magnification
- Low illumination
- Diffuse filter
- Full circle beam
- Place patient face and adjust it
- One sweep Lower lid margin
- One sweep Upper margin lid margin
- Check Caruncle, Puncta
- Pull the lower lid, and ask to look up
- Pull the upper lid and ask to look down
- Hold the upper lid up ask to look right and left
- Give a general look on cornea and iris
- Check setting, now there should be:
- Medium illumination
- Low magnification
- Sharp filter
- Slit beam
- Two sweeps on Cornea, anterior chamber, Iris, Lens
- Maximum illumination
- High magnification
- Sharp filter
- Slit beam
- Check setting, now turn to maximum illumination, high magnification, sharp filter and slit beam
- Two separate sweeps on cornea
- Anterior chamber (Setting for counting cells)
- Iris, lens anterior vitreous face (Setting for counting cells)
- Scleral scatter
- Retro illumination
- I would like to evert upper lid, check corneal sensation, stain with fluoresin, check intraocular pressure and perform gonioscopy.
- Thank the patient, make him sit back and turn off the slit lamp
Signs likely to be missed on slit lamp:
- Difference in corneal diameter
- Heterochromasia
- Anisocoria
- Mild ptosis
- Herpes Zoster scars
For anterior chamber depth:
- Set the slit beam mounting at 60 degrees to microscope
- Use horizontal slit beam
- Adjust slit beam to join corneal and iris reflection.
- Measure slit 3 X 1 mm length and multiply by 1.4 for anterior chamber depth in mm.