how frequent should we conduct eye exams for normal px
below 16 and above 60: annually
everyone else: every 2 years
how frequent should we conduct eye exams for at risk px
below 16 and above 60: every 6 months or earlier if indicated
everyone else: annually or earlier if indicated
why do we need photo documentation?
provide record of anomalies
future comparison
communication betw px and us
px education
where are photos taken and what machines are used?
- anteriorly: slit lamp (anterior structures) , specular microscopy (endo cells, check for pleomorphism and polymegathism), ext ocular photography
- posteriorly: fundus photography
what does gonioscopy and volk lens photography do?
gonioscopy: ant chamber angle
volk lens: fundus
what are the 3 devices available for fundus photography?
- optos daytona
- zeiss fundus cam
- topcon
what are the 3 advantages of optos daytona?
- able to perform on small pupils
- large view of fundus (200 deg)
- no dilation required
what are the 4 disadvantages of optos daytona?
- expensive
- not actual retina colour image
- px need to be able to sit up (mobile)
- difficult if px does not understand instruction
describe the function of zeiss fundus camera. what is one disadvantage?
provide 45 deg view of the fundus.
can be tricky with small pupils or media opacities
in general what are the 3 challenges faced in fundus photography?
- small pupils
- media opacities
- poor fixation (cannot stay still)
what is used for ocular imaging?
optical coherence tomography (OCT)
describe 3 characteristics of OCT
- non invasive
- non contact
- produce cross sectional images of layers of structures (anterior and posterior)
what structures are shown in anterior OCT?
- corneal thickness
2. ant chamber angle
what structures are shown in posterior OCT?
- macula
- retina
- optic nerve
what are 3 limitations of OCT?
- pupil size (>4mm)
- medial clarity (edema, dense cataract and vitreous haemorrhage)
- high astig / decentered IOL
what are the 3 artificial defects of OCT scans?
- blinking (appear as black gaps)
- movement of eye (wavy retinal contour)
- improper alignment of ONH (RNFL analysis abnormalities)
what to do if these defects are seen?
retake scan
true defects and pathology will appear in repeated scans
