Assessing Ocular Health Flashcards
when can blepharitis most likely have a bacterial cause?
If there is discharge
if you need to dilate a patient, when do you do van herrik?
before you dilate them
what is the order of checking eyes on a slit lamp?
- external structures and adnexa
- lids and lashes
- conjunctiva (palpebral and bulbar)
- sclera
- lumbus
- cornea
- tears
- anterior chamber
- iris and pupil
- lens
- anterior vitreous
- retina
for diffuse illumination:
beam width?
angle?
mag?
observation?
-wide
-o
-x10
- diffuse filter so lids and lashes, general overview
for parallelepiped,
beam width?
angle?
mag?
observation?
-2mm like thick optical section
-45
-x10
-depth and size
for optic section,
beam width?
angle?
mag?
observation?
very thin and bright
-45
-x10
-depth like lens opacity and foreign body
for specular reflection
beam width?
angle?
mag?
observation?
2-3mm parallelepiped
-30-45 for lens 45-60 for tear film
-x16
-anterior lens, corneal endothelium, precorneal tear film
for indirect illumination
beam width?
angle?
mag?
observation?
- 1-2mm parallelepiped
-45
x10
-fine blood vesseles, microcysts, areas that become bleached with excess light
for conical beam
beam width?
angle?
mag?
observation?
-1mmx1mm dot
-45
-x16
anterior chamber cells and flare
for sclerotic scatter
beam width?
angle?
mag?
observation?
-2-3mm parallelepiped
-45-60 decoupled
-x10
-corneal abnormalities, glowing ring of light around cornea seen when healthy
for retro illumination:
beam width?
angle?
mag?
observation?
-fairly wide
-varies because it requires decoupling
-start on x16
-you can see microcysts, infiltrates, debris on corneal epithelium, vacuoles of anterior lens, crystalline lens opacities, CL deposits and neovascularisation
for iris transillumination,
beam width?
mag?
observation?
-beam aperture should match the pupil size or be smaller than the pupil to avoid iris reflections
-10-16x
-to detect iris problems as a red reflex
give some iris problems that iris transillumination technique can be used to detect
- Pigment dispersion syndrome (PDS)
- Pseudoexfoliation syndrome (PXF)
- Acute angle-closure glaucoma
- Fuch’s uveitis syndrome
- Herpetic iridocyclitis
- Trauma
what is Shaeffer’s sign?
he presence of
a collection of brown pigmented cells in the anterior
vitreous following a PVD.
explain what to do if your patient presents with shaeffer’s sign
refer them for urgent vitreoretinal assessment as this usually indicates posterior vitreous detachment (PVD) and/or retinal detachment (RD)
from a digital photography photograph, how do you tell which eye is which?
if the optic nerve in the picture is on the right side then it is the RE and if its on the left side then it is the LE
what are the positives of direct opthalmoscopy?
- Portable, hand-held
- Image real, upright, erect
- High magnification 15x for emmetrope
- Can assess for media opacities (cataract)
- Assessment of spontaneous venous pulsation
- Dilation not required
- Less expensive
- Easy to use
what are the positives of VOLK?
- Binocular technique (provides stereoscopic view)
- Image is real, aerial, reversed, and inverted
- Variety of lenses allow for different magnifications
and fields of view - Slit lamp allows a range of magnification
- Dilation not always required
- Less affected by media opacities compared to
direct ophthalmoscopy - Less affected by ametropia
what are the negatives of direct opthalmoscopu?
- Narrow field of view (less than 2DD)
- Close working distance
- No stereopsis
- Image affected by refractive error
what are the negatives of VOLK?
- Bulk equipment
- Expensive
- Needs patient cooperation
- Not suitable for all patients (e.g., patients with
mobility issues, children)
what are the positives of fundus photography?
- Allows immediate viewing of the image
- Offers a larger retinal field of view (up to ~50°)
- Can be used with and without dilation of the patient
- Can be used in testing room to explain finding to patients
- Allows storage of photos and comparison from previous visits
- Different filters and dyes available to allow for different types
tests - Quick and simple technique to master
what are the negatives of fundus photography?
- Image produced in two dimensional, unlike 3D in indirect binocular biomicroscopy
- The presence of cataract (reduced clarity)
- Not portable
- High cost
- Not suitable for all patients (e.g., patients with back/neck issues, not for all children)
- Needs patient cooperation
what are the positives of Optomap?
- Non-invasive
- Images take less than a second
- Dilation not required
- Simultaneous view of the central pole, mid-
periphery and periphery - Less affected by pupil size, media opacities,
aberrations
what are the negatives of Optomap?
- No stereoscopic view
- Needs patient cooperation (aligning the
patient) - Do not get true colour image of the
retina
what are the positives of OCT?
- Non – invasive technique
- Instant imaging of the eye
- High repeatability
- Can get quantifiable measurements e.g., retinal thickness.
Able to document small lesions of the retina and choroid - Can be used to monitor/predict patient’s conditions
what are the negatives of OCT?
The presence of cataract can interfere with the imaging
* Patient cooperation required
* Needs training to succeed the acquisition of optimal images
