Fundus Ocular Photography
Cliff Stephens, O.D.
Fundus Photography - The Specifics
A. General Notes on Fundus Cameras
1. fundus camera is a type of "ophthalmoscope" or "funduscope"
2. some can view and image structures other than the retina
3. portability, table top vs. hand-held cameras
4. mydriatic vs. non-mydriatic retinal cameras
rule of thumb: cameras work best with dilated pupil, even non-mydriatic type
5. stereo photography
some cameras capable of taking stereo-paired photos from a single shot
usually very expensive!
stereo photos usually obtained by technique on non-stereo camera
6. pricing (refer to Dr. Rumsey's notes on fundus photography/cameras)
B. Clinical Uses of fundus camera
posterior retina and optic nerve
peripheral retina
anterior segment (gross)
i.e., cataracts in retroillumination, lids, iris, NVI during FA.
facial photographs
fluorescein angiography
C. Parts of fundus camera
D. Fundus Photography Procedure:
1. set-up
patient education/consent
slide log sheet
exposure/slide #, patient name, eye, structure,
(possible) diagnosis, [close-up]
preceptor - always include preceptor's name!
Remark if stereo-paired photos
2. power on (right front side of camera)
3. make sure film loaded in camera! Do NOT open camera door!
(refer to slit lamp photography notes)
4. load new film cartridge (if necessary)
(refer to slit lamp photography notes section)
100 speed color slide film - 35 mm
5. set flash intensity
flash setting determined by speed of film
and magnification (field of view)
Davie fundus camera:
flash unit built-in to camera = flash panel
flash setting label below flash panel
100 speed color film … use flash setting #36
background illumination adjusts automatically for higher mag images
- increases for 20 degree field of view.
NMB, Opa, Broward fundus cameras:
separate flash unit
flash setting 100 speed color film = #36 on low mag photos
= #75 on high mag photos
need to manually change flash setting for different magnification
6. focus eyepiece, remove lens cover,
7. make sure FA barrier filter OUT
8. patients name on name plate and/or
take photo patient's name or face for identification (if directed)
9. obtain full fundus view
patient looks straight ahead
pull camera back until can see whole globe and center pupil using joystick
move in towards pupil using joystick, keeping centered
until maximize field of view and quality of view
(sets camera exit pupil coincident with eye entrance pupil)
too far back,
too close to patient --} creates white or blue ring around view
too far to one side --} creates white or blue arc on side of view
use small vs. mydriatic pupil setting to maximize view
use small pupil setting
on larger pupil --} tend to get dark artifact in center
use large pupil setting
on small pupil --} tend to increase ring artifact
10. obtain focused view
focus NOT like slit lamp: use focusing knob, not joystick
- joystick controls view in.
focus for high refractive errors (ametropias):
use ametropia compensation knob
no high ametropia correction = zero sign
high hyperope = plus sign
high myope = minus sign
aphakia = "A" sign
(aphakes typically more plus than phakic high hyperopes)
astigmatism = use cylinder wheel,
pull out slide for either 3 or 6 DC,
rotate cylinder with wheel until looks clearest
(no axis markings)
NOTE: other use for cylinder wheel is for peripheral fundus photos
11. control patient fixation
flashing light on arm (outside camera)
good for: photos on "bad eye" of "monocular" patient
peripheral retina photos
pointer (inside camera)
typically better than using flashing light
except for above exceptions
12. select and modify view
a. changing illumination
background illumination (slide rheostat)
usually use close to full brightness, especially dark fundi
red free filter (i.e. NFL defects, hemorrhages, etc.)
need to increase background illumination slightly
b. changing magnification (field of view)
50 degrees, 35 degrees, 20 degrees
change background illumination or flash with change mag
(see flash setting section above)
higher magnification gives blurrier photos (less resolution)
Tips for high mag imaging:
orient and center area to photograph on low mag first,
then change to high mag,
may need to hold and move fixation pointer during photos
c. types of views
facial photographs: patient sits back away from camera,
focus with focusing knob
uses: identification photos; orbit, lid, eye movement conditions
generally hand held camera gives better images
anterior seg: patient's chin in rest,
focus more anterior using "+" or "A" setting
and pull fundus camera back, fine focus with focus knob
generally slit lamp camera works better
vitreous: as anterior seg photos, but DO NOT pull camera back
"+" lens focuses deeper into vitreous than "A" lens
uses: vitreal hemorrhage, floaters, asteriod, vitritis, etc.
posterior pole: general procedure described in this section
optic nerve (glaucoma, optic neuritis, AION, etc.)
macula (ARM, solar ret, CME, macular dystophies, bull's eye, etc.)
posterior retina, arcades (diabetic retinopathy, NFL defects, etc.)
peripheral retina:
usually use low magnification, wide field of view setting
patient looks in direction of retina want to view
move camera in opposite direction to view more peripherally
(i.e. like doing BIO) if necessary
swing camera left for right gaze, swing right for left gaze
rotate camera up using vertical angle knob for down gaze
rotate camera down for up gaze
may need to use cylinder compensation due to induced oblique astigmatism
13. take photos
press shutter release on joystick (or on camera)
can take sequential photos very quickly
(fluorescein or quick stereo set)
make sure film advancing (rewinding/carrier spool should spin CCW)
single vs. stereo-paried photos
14. stereo-paired photos
create lateral disparity between 2 images similar to slit lamp photography
create left vs. right image with joystick,
NOT by swinging camera left/right
swinging camera will change overall view seen by camera
center view with joystick in center
move joystick slightly left, take photo, slightly right, take photo
NOTE:
"stereo" switch on left front is only a lock to limit camera movement
inform patient will take 2 photos quickly back-to-back
(helps fixation and getting good pairs)
15. rewind, remove, replace film (if necessary)