This document outlines various methods used in eye examinations, including:
- External examination of the eyes and surrounding structures.
- Assessment of visual acuity using charts at both near and distance.
- Testing of color vision and pupillary response.
- Evaluation of eye movements and alignment using cover tests.
- Assessment of binocular vision and screening for macular diseases using an Amsler grid.
- Examination of the anterior and posterior segments using a slit lamp and indirect ophthalmoscope.
- Measurement of intraocular pressure through tonometry and assessment of the anterior chamber angle through gonioscopy.
- Determination of central corneal thickness through pachymetry.
3. EXTERNAL EXAMINATION:
• Look for any ptosis.
• Look for lagophthalmos
• Note any unusual growths or lesions that may require a biopsy.
• Measure proptosis or enophthalmos with an exophthalmometer.
• Perform a full cranial nerve exam for patients with diplopia or other
neurologic symptoms.
4. VISUAL ACUITY
(VA)
• Monocularly
• Un-aided VA
• VA with glasses
• BCVA (Best Corrected VA)
• Binocularly VA
• Pinhole VA (if BCVA is worse)
If patient is unable to see the biggest
optotype, the progression is:
• CF (Counting Fingers)
• HM (Hand Movement)
• Perception of Light (PL) with projection
• PL without projection
• No Light Perception (NPL)
VA is measured first for the
distance then for near. Most
commonly carried out using
a Snellen chart, with the
subject reading the chart
from the standard distance.
Steps for evaluating VA:
5. • Children who are too young to
use “Allen pictures” employ the
Central Steady Maintain (CSM)
approach.
Near VA:
• Near VA is a sensitive indicator
for the macular disease.
• Near chart held at comfortable
reading distance.
• Patient wear necessary distance
correction together with a
presbyopia correction.
TOOLS:
• Snellen chart
• Log MAR chart
• ETDRS chart
• Computer chart
• Jaeger chart
6. COLOR VISION TESTING:
• It is useful in the evaluation of optic nerve disease and
in determining the presence of a congenitally
anomalous color defect.
• Color vision depends on 3-populations of retinal cones
with specific peak sensitivity:
Blue (tritan): 414-424nm
Green (deuteron): 522-539
Red (protan): 549-570nm
• If any cone pigment may be deficient (e.g.;
protanomaly-red weakness) or entirely absent
(protanopia- red blindness)
• Acquired macular disease tends to produce blue-yellow
defects, and optic nerve lesions red-green defects.
TOOLS:
• Ishihara test
• City University test
• Hardy-Rand-Rittler test
• Farnsworth-Munsell
100-hue test
7. PUPILLARY EXAM:
• Look for anisocoria, if present check for the pupil size
• Check the reactivity of each pupil with a pen light or Finoff trans-illuminator.
• Use the swinging flash light test to look for a relative afferent pupillary
defect.
8. EXTRAOCULAR MOTILITY AND
ALIGNMENT:
• Test with both eyes open to test versions in six cardinal positions of gaze.
• Repeat monocularly to test ductions.
• Use cover/uncover tests to assess for heterotropias.
• Use the alternate cover test to assess the total amount of deviation.
9. BINOCULAR VISION TESTING:
• Evaluating the sensory status of children is an essential part of the
pediatric eye examination
• Testing stereo acuity is an excellent way of screening for various
conditions that may interfere with the development of binocular
depth perception.
There are two different types of stereo tests:
• Contour stereopsis tests like Titmus test
• Random dot tests like Randot or Lang tests.
10. AMSLER GRID:
• Evaluates 20 of the visual field
centered on fixation.
• Useful for screening and
monitoring macular disease. It
measures between 5 and 6 mm
in diameter.
• Patients with risk of
CNV(Choroidal
Neovascularization) should
provided with an Amsler grid
for regular use at home.
• Relative scotoma
• Absolute scotoma
• Metamorphopsia
• Micropsia
• Macropsia
11. SLIT-LAMP BI-MICROSCOPY:
Anterior Segment:
• Direct illumination: use to detect
gross abnormalities
• Scleral scatter: to detect stomal
haze, cellular or lipid infiltration.
• Retro-illumination: use after pupil
dilation to detect fine epithelial and
endothelial changes.
• Specular reflection: shows
abnormalities of the endothelium
Posterior Segment:
Different dioptric power lenses are
used to view fundus and optic nerve.
60D
90D
78D
12. INDIRECT OPHTHALMOSCOPE:
• Used to refer to the head mounted technique.
• It allows retinal visualization through a greater degree of media
opacity than slit lamp bi-microscopy.
• Lens of various powers are available:
20D
28D
40D
13. TONOMETRY:
Goldmann Tonometry:
• It states that for an ideal, dry, thin-walled sphere, the pressure inside the
sphere (P) equals the force necessary to flatten its surface (F) divided by the
area of flattening (A) i.e. P=F/A
• It is an accurate variable-force tonometer consisting of a double prism.
Other forms of Tonometry:
• Pneumo-tonometry
• Portable applanation tonometry
• Dynamic contour tonometry
• Electronic indentation/applanation tonometry
14. GONIOSCOPY:
• It is a method of evaluating the anterior chamber angle (ACA) and
can be used therapeutically for procedures such as laser
trabeculoplasty and goniotomy.
Other means of angle assessment:
• Anterior Segment Optical Coherence Tomography (AS-OCT)
• High frequency ultrasound biomicroscopy (UBM)
15. CENTRAL CORNEAL THICKNESS
(CCT):
• It can be measured using pachymetry or by Orbscan,
• The normal distribution is 540 ± 30 microns.
• Eyes with a thin cornea have a true IOP that is greater than the
measured IOP.
• Eyes with a thick cornea have a true IOP that is lower than the
measured IOP.
• Patients with NTG tends to have thin CCT measurement.
• It is a vital element when determining the risk of conversion to
glaucoma in individuals with raised IOP.