The ophthalmic examination
The Ophthalmic Examination
A complete history includes four aspects: Family history
(refractive errors, strabismus, cataract, glaucoma, retinal
detachment, retinal dystrophy) Medical history
: - systemic disorders (diabetes mellitus, hypertension, infectious
diseases, rheumatic disorders, skin diseases)
- medications (steroids, chloroquine, Amiodarone, Myambutol, chlorpromazine)
strabismus, amblyopia, corrective lenses, posttraumatic
conditions, surgery, eye inflammation Current history:
What symptoms does the patient present with? (impaired vision,
pain, redness of the eye, double vision) 2. Visual acuity
The sharpness of near and distance vision is tested separetly for each eye.
Uncorrected and corrected visual acuity are tested using Snellen chart. It is a
universal standard used by most clinicians. The patients is asked to recognize
special symbols called optotypes. VA is a fraction in which the numerator indicates
the distance of the patient from the chart and the dominator indicates distance at
which a normal eye can read the line.
Visual acuity = actual distance
Normal VA is 5/5 (20/20) or 1.0 when the actual distance equals the standard
Plus lenses (convex lenses) are used farsightedness ( hypermetropia) and minus
lenses for nearsightness (myopia) and cylindrical lenses for astigmatism.
If the patient cannot discern the symbols on the eye chart of 5 meters (20 feets) the
examiner shows the patient the chart at a distance of 1 meter or 3 feet. If the patient
is still unable to discern any symbols the examiner has the patient count fingers,
discern the direction of hand motion and discern of a point light source. CF count
fingers, HM hand movements, PL perception of light, NPL no perception of light. 3. Maesurement of Intraocular Pressure
comperative palpation of both eyeballs that can detect increased
intraocular pressure. The the examiner places his fingers on the patient’s head and
palpates the eye through the upper eyelid with both index fingers. The test is
repeated on the contralateral eye for the comparison. Schiötz indentation tonometry:
The examination measures the degree to which
cornea can be indented in the supine patient. The lower the intraocular pressure the
deeper the tonometer pin sinks and the greater distance the needle moves. The
harder the eyeball the shallower the indentation and the smaller the movement of
indicator needle. The tonometer is placed on the anesthetized cornea. Applanation tonometry:
This method is the most common method of measuring
intraocular pressure. It is a slit lamp measurement of intraocular pressure. We put
anestheszing eyedrops and fluorescein drops into conjunctival sacc and then the
tonometer tip is placed on the cornea. The cornea is applanted (flattened) over an
area measuring precisely 7,35 mm². This external pressure required is directly
proportional to intraocular pressure. Pneumatic non contact tonometry:
The electronic tonometer directs a 3 ms blast
of air against the cornea. The tonometer records the deflection of the cornea and
calculates the intraocular pressure on the basis of this deformation. 4. Examination of nasolacrimal duct:
Conjunctival fluorescein dye test:
It is tested by instilling 10% fluorescein solution
in the conjunctival sac of the eye. If the dye is present in nasal mucus expelled into
paper tissue after 2 minutes the lacrimal duct is open. Probing and irrigation:
They are used to locate stenoses. The punctum is dilated by
rotating a conical probe. Then the lacrimal passage is flushed with a physiologic
saline solution. Schirmer tear testing:
This test provides information on the quantity of watery
component in tear secretion. A strip of litmus paper is inserted into the conjunctival
sac of the temporal third of the lower eyelid. After about 5 minutes at least 15 mm of
paper should turn blue due to the alkaline tear fluid. Values less than 5 mm are
abnormal. Tear break – up time:
This test evaluates stabillity of the tear film. Fluorescein dye is
added to the corneal tear film. The examiner observes the eye with a slit lamp and
cobalt blue filter and notes when the first signs of drying occur without the patient
closing the eye. Normal TBUT of at least 10 sec. 5. External examination ( orbital area, eyelids, ocular motility).
a. Orbital cavity.
Palpation of the orbital rim and lids. Unilateral or bilateral enophthalmos ( recession
of the eyeball within the orbital cavity) or exophthalmos ( protrusion of the eyeball).
Exophthalmometry: The Hertel mirror exophtlalmometer measures the anterior
projection of the globe beyond the orbital rim. The devices measures prominence of
the eye from anterior surface of the cornea to the temporal bony rim of the orbit. The
exophtalmometer is placed on the lowest point of the temporal zygomatic. The
examiner reads the value of the extraorbital prominence of the anterior surface of the
cornea on the scale. The difference between the two sides greater than 2 mm is
abnormal. b. Ocular motility.
With the patient’s head immobilized the examiner asks the patient to look in each of
nine diagnostic positions of gaze(straight ahead, right, upper light, up, upper left,
down, lower down…), This allows the examiner to diagnose strabismus, paralysis of
ocular muscles and gaze paresis.
c. The lids.
The shape, eyelid position, skin of the eyelid, width of the palpebral fissure.
When the eye is open and looking straight ahead the upper lid should cover the
superior margin of the cornea by about 2 mm. If more then ptosis of that lid may be
present. We should note if the lids evert or invert. When the lower lid is turned away
from the eye ectropion is present. When the lid is turned inward toward the globe the
entropion is present. The width of the palpebral fissure is normally 6-10 mm and the
distance between the lateral and medial angles is 28-30 mm. To evaluate the
palpebral conjunctiva we can do simple eversion of the upper and lower eyelid. In this
way we can also evaluate the superior and inferior fornix. The patient relaxes and
look down. The examiner places a swab superior to the tarsal region of the upper
eyelid, grasps the eyelashes of the upper eyelid between the thumb and the
forefinger and everts the eyelid using the swab ac a fulcrum. This same we can
perform using finger or Desmarres eyelid retractor. When we examine the lower
eyelid the patient looks up and the examiners pulls the eyelid downward close to the
anterior segment. 6. The examination of anterior segment of the eye
( the conjunctiva, cornea,
anterior chamber, iris, lens, pupil, anterior part of the vitreous body). a. Conjunctiva
The bulbar conjunctiva can be evaluated by direct inspection under a focused light.
Normally it is shiny and transparent. The other parts of the conjunctiva will not be
normally visible. They can be inspected by everting the upper or lower eyelid. b. Cornea
• Slit lamp examination
• Fluorescein staining of cornea
– it is useful in diagnosing defects of corneal
epithelium. Illumination with a cobalt blue filter enhances the fluorescent effect. This dye method can reveal corneal epithelial defect (corneal erosion).
Corneal topography – the keratoscope (Placido’s disk) permits gross evaluation of the uniformity of the surface of the cornea. This instrument consists of a round disk marked with concentric black and white rings around a central aperture. The examiner holds the disk in his hand and looks through the aperture. The surface of the cornea is now normally evaluated by computerized corneal topography (videoceratoscopy). In this examination the contours of the cornea are measured by a computer in the same manner as keratoscope.
• Determining corneal sensitivity
– corneal sensitivity can be evaluated with a
distendend cotton swab. The patients looks straight ahead while the examiner holds the upper eyelid and touches the cornea anteriorly. Decreased sensitivity can provide information about trigeminal or facial neuropathy or may be a sign of a viral infection of the cornea.
• Measuring the density of the corneal endothelium
– specular microscopy
permits a precise endothelial cell count while simultaneously measuring the thickness of the cornea (pachymetry). A sufficiently high density of endothelial
cells is very important for the transparency of the cornea. More than 2000 per mm² is normal.
• Corneal pachymetry
– measurement of the thickness of the cornea.
c. Anterior chamber
The anterior chamber is filled with clear aqueous humor. It is important to evaluate
the depth of the anterior chamber. d. Iris
Slit lamp examination – we evaluate surface structure – crypts and trabeculae e. Pupil
Pupil size and shape
Testing the light reflex – direct light reflex, indirect light reflex. f. Gonioscopy and morphology of the anterior chamber angle angle structures.
The angle of the anterior chamber is evaluated with gonioscope placed directly on
the cornea. Gonioscopic image of the angle – Schwalbe’s line (end of Descemet’s
membrane), trabecular meshwork, Schlem’s canal, scleral spur, the ciliary body
band. g. Vitreous body
- slit lamp examination, ultrasonography, ophthalmoscopy 7. Examination of the fundus of the eye – ophthalmoscopy.
It permits the visualization of the optic disc, arteries, veins, and retina. Adequate
papillary dilatation is necessary. Optic disc margin should be sharp and well defined.
It is about 1,5 mm. Amsler grid testing
– is a useful method of evaluating the function of the macula.
This test is carried out by having the patient look with one eye at a central spot on a
page with horizontal and vertical parallel lines. The patient is asked to note
irregularities in the lines. Irregularities may be reported as lines that are wavy, seem
to bow or bend. 8. Additional examinations in ophthalmology
– fluorescein and indocyanine
angiography, electrophysiology, ultrasonography, computerized tomography, MRI,
color vision testing, visual field examination. a. Color vision testing
There are two types of retinal fotoreceptors called rods and cones. Cones are placed
in macular area and rods peripherally in the retina. Cones are responsible for daytime
vision – fotopic vision and color vision and rods are responsible for night or scotopic
vision. Three sets of cones: the first one consists of longer wave length sensitive
cones – L cones. The second set consists of more middle sensitive cones – M cones.
The third – short wave length. S cones. It depends on the max sensitivity of
photopigments or on the max absorbtion of the visible light spectrum. The visible light
spectrum ranges from 380 – 670 nm. There are three basal colors and the other hues
are the mixture of them. Red/green color vision defects are often seen in optic nerve
or inner retinal disease. Blue/yellow defects are seen in outer retinal layer (macula) and more peripheral retina.
• Ishihara plates
– it is a qualitive test. The book contains different patterns,
letters, shapes and numbers composed of small color dots surrounded by confusion colors. The patient with color vision defects cannot read these letters.
• Panel D15 – Farnsworth Munsell test
. The patient is presented with small
color plates that he must select and sort according to a fixed blue color marker. The patient with color vision defect will confuse markers.
• 100 HUE test
– 100 plates which should be placed in propter sequence
according to the colors of the rainbow in the right order.
– it is a quantitative evaluation. The most accurate instrument
for classifying color defect. There is a split screen and we ask the patient to view the screen. There are two halves and the patient tries to match both halves by mixing varying proportions of red and green or green and blue colors.The final adjustment allows to calculate the anomaly ratio.
b. Visual field examination (perimetry):
The visual field is defined as the field
of perception of the eye at the rest with the
gaze directed straight ahead. It includes all points in space that are simultaneously
visible when the eye focuses on one point. Only one eye is examined at a time. Light
markers appear in the hemisphere of the device. The patient signals that he or she
perceives the marker by pressing a button that triggers an acoustic signal. \ Blind spot
is represented by an absolute scotoma corresponding to the scleral canal
through which the retinal nerve fibres leave the canal at the optic disk. Isopter
– is a line drawn in a visual field chart which connects all points which have
this same sensitivity in the retina. There are two types of perimetry – kinetic
involves moving points of light that
travel into the hemisphere. The patient is asked to signal when he notice the marker
and indicate when it disappears and again when it reappears. Static perimetry
(computerized involves the static light markers and their intensity increases until
there are perceived. Scotoma
is a depression of sensitivity surrounded by areas of relatively well
preserved function of retina. Relative scotomas
– when some visual sensation
remains and absolute scotomas
when there is no visual sensation and no matter
how bright is the stimulus. Scotomas are classified by location,(central, paracentral)
size, shape (round,sectoral,arcuate). Indications:
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