Prelim- Chapter 7 Primary Care Flashcards
Also known as “squint” or “strabismus”
Tropia
Purpose of Preliminary examination
to detect any gross anomaly such as:
high refractive error
binocular vision anomaly
disturbance of ocular motility
ocular or systemic diseases.
Order of ocular examinations
- Visual Acuity
- Tests of ocular motility and binocular vision
- Tests of Color Vision
- Visual Field screening
a. Confrontations - Tonometry
- Blood Pressure measurement
- External examination (anterior segment Evaluation)
a. Slit lamp examinations - Internal examination (Posterior Segment Evaluation)
a. Fundus Evaluation
i.Direct
il.Indirect
Special Investigations:
A-scan
Ultrasound (B-scan)
Perimetry
Pachymetry
Goniosopy
Ocular photodocumentation
Fundud Fluorescein Angiography
Contrast Sensitivity Test
Amsler grid Testing
Electrodiagnostic tests
Neurodiagnostic tests
Keratometry
Exophthalmometry
Ophthalmodynamometry-for carotid artery insufficiency; transient loss of vision
is assessed to obtain visual status of each eye.
Visual acuity
helps differentiating abnormality due to dioptric apparatus or one due to organic disease.
Pinhole test
Defect in dioptric apparatus is further confirmed by___.
retinoscopy
VA charts
Snellen’s test types
E test chart
Landolt’s broken ring test types.
SG chart
kay picture cards
Optokinetic nystagmus test
forced preferential looking charts
LogMAR charts
• It is recommended that you stand back and observe the whole patient for a few seconds before carrying out the examination.
Sometimes, observation alone is sufficient to give you the diagnosis and the examination only serves to confirm it.
• Observation is conducted for Head posture, facial asymmetry, Forehead, Eyebrows, ocular posture, ocular movements
General observation
Determined by the position of the two visual axes in the primary position of gaze.
Ocular posture
position of light reflex is seen by asking the patient to see on the torch light. Reflex on the temporal side of pupil indicates the eye is convergent & if it is on the nasal side the eye is divergent.
Hirchberg test:
ask patient to focus on a near target and follow it as she traces a broad letter “H.” This tests the ability of the e yes to follow the target. It will indicate any problem with th e nerve supply to the eye muscles or problems with the m uscles themselves.
Ocular motility
Done either in
• Diffused light using torch Or Focal illumination using slit lamp or loupe.
• Procedures go as follows:
Asymmetry in wrinkling of foreheads
Eyebrows
Eye lashes
Eye lids
Conjunctiva
Method of examination
Bulbar coniunctiva is examined by retracting the upper lid & lower lid by index finger & thumb respectively.
• Lower palpebral conjunctiva is seen by asking the patient to look up & then pulling the lower lid down.
• Upper palpebral conjunctiva & fornix is seen by asking the patient to look down and then grasping the lid margin by thumb & index finger the lid is everted using index finger as fulcrum.
External ocular examination
• Points to be noted while doing external examination
• Redness or congestion.
• Discharge.
• discoloration.
• Chemosis.
• Changes on the surface.
• New formations: papillae, follicles, concretions, pinguecula, pterygium, phlycten, tumors, cysts etc.
• Ulcers & granulomas.
• Membranes & pseudomembranes.
• Scar
• Foreign bodies.
Examination of sclera:
• The white sclera is visible through conjunctiva.
• The points to be noted are:
Colour
Congestion.
Pain & tenderness.
Traumatic perforations.
Examination of cornea
t should be done under slit lamp examination.
• The points to be noted are
Size: normal cornea is 11 mm vertically & 11.7 mm horizontallv.
• Curvature
• Surface is also assessed using placido’s keratoscopic disc. Other tests for topography are photokeratoscopes.
Transparency
Opacity
• Foreign bodies
Abrasions
Ulcerations
• Vascularization
• Corneal sensations
• Corneal endothelium examination using specular microscopy.
• Corneal thickness (using pachymetry) estimation.
Corneal staining is performed when epithelial defect is suspected.
In this flourescense strip is placed in the inferior fornix. Patient is asked to blink and then cornea is inspected under cobalt blue light.
Cornea is translucent, smooth and avascular.
Examination of anterior chamber
• It’s done best under slit lamp.
•Depth and contents are noted.
• Normally anterior chamber is clear with aqueous humor.
• Following contents in the AC are noted:
• Hyphaema
• Hypopyon
Aqueous flare & cells
• Lens
• Lens particles
Examination of Iris
•Normally iris is flat & color varies
• Things to be noted if present
• Adhesions (synaechiae)
• tremulousness (iridodonesis)
• new vessel formation
• pupillary membranes
• Colobomas
• prolapse
• irridodialysis
• nodules
• Cysts
Ocular motility and binocular vision
a. Cover Tests
b. Corneal Reflex Tests
c. NPC Testing
d. NPA Testing
e. Motility Tests
F. Tests of Pupillary function
g. Tests of stereopsis
Different ocular postures are:
esotropia
exotropia
hypotropia
hypertropia
Incyclotropia
excyclotropia.
It is revealed by cover-uncover test.
_____ is done by covering one eye and watching the other eve for a fixation movement. Uncover test is done by watching they eye just uncovered.
Cover test
can be used to test visual acuity for preschool children who have not yet learned the alphabet. As an assistant points out the pictures, beginning with the birthday cake at the top of the chart, the child is asked to name, or describe, the picture or pictures in each row.
The Birthday Coke project-o-chart
For children between the ages of about 3 and 6 years who cannot recogntze enough letters to make the use of a standard letter chart,
The child is given a wooden or plastic letter E and instructed to point the “legs” of the E in the same direction as those of the E on the chart.
The Tumbling E Chart.
is an alternative to the tumbling E chart. The examiner states that “somebody has taken a bite out of this doughnut and asks the point at the part of the donut that is missing
The landolt C chart
consists of a set of seven cards, each containing a single picture, and can be used for children 2 years of age and older. The child is first shown the cards at close range, with both eyes open, and is asked to name each picture (the names in many cases will differ from the names an adult would be expected to use). One eye is then occluded, and the examiner shuffles the cards–using the cards that appear to have the most meaning for the child and presents them individually at increasingly greater distances.
The Allen preschool vision test
consists of letter charts designed for use at 10- and 20-foot distances together with sets of miniature eating utensils and a number of toys.
The child is given a large card, called a key card, and is asked to fod the letter on the card that is the same as the letter on the distance chart. The eating utensil set includes a small set of utensils held by the examiner (first at 10 feet and then at 20 feet) and a large set held by the child.
The STYCAR (Screening lest for Young Children and Retardates) visual acuity test
Like the STYCAR test, provides a large key card for use by the child. The child is asked to point to the letter on the key card that is the same as the letter shown on the distance chart
The distance chart is in the form of a spiral-bound booklet, with one letter presented on each page. The Sheridan-Gardiner test also includes a reduced Snellen chart for near testing.
The Sheridan-Gardiner visual aculty test
have a “lap card” that the child holds and a visual acuity chart at 10 or
20 ft.
Contrary to many reports still in optometric literature, a 3-year-old child should be expected to have visual acuity of approximately 20/20.
The HOTV letter chart and the Lea symbols,
also called the cover-uncover test
Unilateral cover test
the practitioner can determine the presence or absence of a tropia also known as strabismus, or squint.
And by means of the alternating cover test, he or she can determine whether a phoria or a tropia is present but cannot differentiate between the two. If the unilateral cover test results in a negative finding, a positive finding on the alternating cover test indicates the presence of a phoria.
Because the______ can interfere with the manifestation of a tropia, it is customary to perform the unilateral cover test first.
alternating cover test
The Unilateral Cover Test
While wearing his or her own spectacle correction, if any, the patient’s attention is called to a letter on the 6-m Snellen chart.
To ensure that accommodation is relaxed, the letter should be no larger than one line above the patient’s corrected acuity with the worse eye, and the patient should be instructed to keep the letter in sharp focus. The practitioner is seated opposite the patient, with his or her head positioned so that it does not block the patient’s view of the chart. Sufficient illumination must be directed toward the patient’s eyes so that the practitioner can observe any eye movement
A tropia may be present at some times and not at others; this is an_____ tropia.
For example, a patient who has intermittent exotropia may be found on one occasion to have right exotropia but on the next occasion to have only a high exophoria.
intermittent
If a tropia is found at one testing distance but not at another, the condition is called ____ .
For example, in some cases of accommodative esotropia, the patient may have no strabismus at distance but may have esotropia at near testing, while in divergence excess, there may be no strabisinus at near but exotropia may he found on distance testing.
Periodic tropia/strabismus.
The Alternating Cover Test
‘The conditions for the alternating cover test are the same as for the unilateral cover test. The patient wears his or her own spectacle correction, if any, and fixales a small letter (one line above best acuity for the worse eye) on the Snellen chart at 6 m. The examiner sits facing the patient. The patient is instructed to keep the small letter in sharp focus.
The examiner places the occluder in front of the right eye, holds it there for about 1 second, and then quickly places it in front of the left eye. The test is repeated several times, the occluder being held in front of each eye for about 1 second before being quickly moved lo the other eye.
A tropia may be either unilateral, in which one eye is always the deviating eye, or alternating, in which either eye may deviate.
Unless the unilateral cover test is repeated several times, an alternating tropia may be missed, and the practitioner may conclude that the tropia is unilateral. Exotropia of relatively recent onset is particularly likely tole alternating.
If the patient has a ——- each
eve will be seen to turn upward or downward just as the cover is removed. Because a phoria is “shared” between the
two eyes, if the right eye is observed to turn downward as it is uncovered, the left eye should be observed to
turn upward as it is uncovered. ‘This indicates that the right
eye, while covered, deviated upward and the left eye devi-
ated downward. This condition could be called either right
hyperphoria or left hypophoria. However, by convention, vertical phorias are always labeled in terms of the hyperphoric
eve.
Vertical Phoria.
In many cases, a patient will be found to have both a lateral phoria and a vertical phoria. For example, if the right eve is observed to turn downward and inward as it is uncovered, the condition would be exophoria combined with right hyperphoria.
À practitioner can enhance his or her ability to detect a small phoria by asking the patient whether the letter on the chart appears to move as the occluder is moved from one eve to the other. If the
patient sees any movement, the practitioner asks whether the movement of the letter is in the same direction or in the direction opposite to the movement of the occluder.
When movement is perceived rather than real (as when one traffic light blinks on white another blinks off), psychologists refer to it as_____
phi movement.
is a convenient test for determining the presence of strabismus at near. It is particularly useful for a child whose results with the unilateral cover test were questionable. In this test, the patient is instructed to watch a penlight or ophthalmoscope bulb that the examiner is holding at a distance of about 40 cm; the examiner observes the corneal reflexes in the patient’s eyes while viewing just above the light source with the dominant eye.
The corneal reflex test
no tropia exists, each corneal reflex will be located approximately 0.5 mm nasal to the center of the pupil. This is because the line of sight makes a small angle (about 5 degrees) with the pupillary axis. This angle, measured from the entrance pupil of the eye, is calied the _____
angle lambda.
Whereas the corneal reflex is normally about 0.5 mm nasal to the center of the pupil, it may be slightly more displaced nasally in some_____ eyes, and it may be near the center of the pupil or even displaced temporally in some ____eyes.
hyperopic
highly myopic
With Hirschberg’s method, in esotropia, the corneal reflex for the deviating eye will be displaced_____ compared with the fixing eye, whereas in exotropia, it will be displaced___.
temporally
nasally
Hirchberg
Eso (temporal reflex)
Exo (nasal reflex)
The angle of strabismus can be estimated on the basis that each millimeter of displacement of the corneal reflex indicates approximately ____ of strabismus.
22 prism
prisms are placed in front of the deviating eye while using the alternating cover test, and the prism power is found that will place the corncal reflex in the same position for the deviating eye as for the fixing eye. This procedure presents the problem that a light source is not an adequate stimulus for accommodation.
Krimsky
is convenient to test for the near point of convergence just after completing the corneal reflex test. As the penlight is slowly brought inward toward the patient’s nose, the patient is asked to report when the light “breaks into two.
The examiner watches the patient’s eyes to determine any loss of convergence not reported by the patient. If one eye turns outward (as shown by an inward movement of the corneal reflex) without the patient reporting diplopia,
determine the_____, the near point of convergence must first be specified in terms of the line joining the centers of rotation of the two eyes. Although the center of rotation of the eve is thought to be about 27 mm behind the spectacle plane, as a matter of conven-lence this distance can be assumed to be 3 cm.
amplitude of convergence
can he determined monocularly for each eye, as well as binocularly, while the patient wears his or her glasses or contact lenses, if any. For monocular determination of the near point of accommo-dation, the left eye is occluded (it is convenient to have the patient hold the occluder), and the patient is asked to keep the 20/20 row of letters on the reduced Snellen chart in. sharp focus as the card is moved closer.
near point of accommodation
Amplitude of Accommodation
If the patient’s refractive error is corrected while the near point of accommodation is measured, the amplitude of accommodation can be calculated simply by taking the reciprocal of the near point of accommodation, expressed in meters. For a near point of accommodation of 8 cm (as measured from the spectacle plane), the amplitude of accommodation is 12.50 D.
When this test is performed while a patient is wearing old glasses or contact lenses, the practitioner does not know whether these lenses adequately correct the patient’s refractive error. Therefore, data on the near point of accommodation, taken through the old lenses, should remain in the recording form as near point of accommodation rather than being converted to amplitude of accommodation.
Several tests have been devised to investigate the integrity of the extrinsic ocular muscles and their nerves, including the——— and the——
broad H test
diptopia field test.
It is designed to test the action of the horizontal rectus muscles (the patient’s eyes fixate a penlight as it is moved into the right-hand and lett-hand fields) and to test the action of the vertically acting muscles, the vertical recti, and the obliques (the patient follows the penlight as it is moved
Broad H test
muscle that turns the eye upward when it is already turned to the right is called a right-hand elevator, and a muscle that turns the eye downward when it is already turned to the right is called a right-hand depressor.
The size of each pupil is measured using a millimeter ruler and estimating pupillary diameter to the nearest half millimeter.
Smith recommended that measurements be made in both a lighted and a semi darkened room, as the pupils may be of equal size in one circumstance and of unequal size in another.
To observe and evaluate direct and consensual pupillary reflexes, the patient fixates on a distant object in a semi-darkened room and a penlight is used to illuminate each pupil, taking care to direct the penlight toward the macular area.
The direct reflex ~ the constriction of the pupil of the illuminated eye- -is easily seen, but it is often difficult to observe the constriction of the opposite eye, particularly if the patient has dark irises.
The level of room illumination should be sufficient for the examiner to observe the constriction of the pupil of the unillumi-nated eve.
To conduct the swinging flashlight test, the patient fixates on a distant object in a semidarkened room. The examiner first illuminates the right eye, then the left, swinging the flashlight from one eye to the other. The procedure is repeated several times, each pupil being illuminated for about 1 second, to establish a rhythm.
Normally, the pupil of each eye will be seen to constrict as that eye is illuminated. However, in the presence of a Marcus Gunn pupil, the pupil of the affected eye will____ slightly when that eye is illuminated.
the pupils of both eyes will dilate when the eye with the Marcus Gunn pupil is illuminated. Because the pupil fails to constrict when illuminated, the condition is sometimes referred to as pupillary escape.
dilate
Many people will be found to have a difference in pupil size between the two eyes sufficient to be detected when measured by a millimeter ruler (a difference of ½ mm or more), This condition is known as_____ and is of no consequence. Smith suggests that when the pupils are found to be of unequal size, the patient should be asked to supply old photographs to help the practitioner determine whether the difference in pupil size is longstanding (and, therefore, likely to be essential anisocoria) or of recent origin.
essential anisocoria
_____is a unilaterally dilated pupil with little or no reaction to light but with sluggish reaction to near stimulation.
It is a relatively common clinical entity, occurring in females ages 20 to 30 who are otherwise healthy. It is thought to be due to a lesion of the_____ and requires no treatment. The moment of truth, according to Smith (tape no. 6), is the slow redilation of the affected pupil (compared with the faster redilation of the normal pupil) when the patient fixates a distant object after intently fixating his or her own finger.
Adle’s tonic pupil
ciliary ganglion
An eye having an____ (having no light perception) will have no direct pupillary reflex but will contract consensually when the fellow 26°C (normal eye is stimulated by light)
amaurotic pupil
Among the causes of a Marcus Gunn pupil is_____, which may be accompanied by optic neuritis or by retrobulbar neuritis (inflammation of the optic nerve behind the globe). Smith (tape no. 6) pointed out that only a minor decrease in visual acuity may be present in an eye with a Marcus Gunn pupil.
multiple sclerosis
_____consists of miosis (a constricted pupil), ptosis (dropping of the upper lid), apparent enoph-thalmos, and a possible decrease in facial sweating on the affected side. The cause is a paralysis of the ocular sympathetic fibers responsible for pupillary dilation. The lesion can be anywhere in the long, complicated sympathetic pathway (in the midbrain, pons, upper spinal cord, middle cranial fossa, and orbit).
Hormer’s syndrome
Fixed , dilated pupil, usually unilateral, due to a central nervous system lesion that compresses the optic nerve. Because the patient with this condition is usually very sick, an optometrist is unlikely to encounter this condition.
Hutchinson’s pupil
is present when the pupils fail to react to light but constrict on convergence.
Light-near dissociation
One of the most common causes is neurosyphilis, in which case the syndrome is known as the
Argyll Robertson pupil.
Argyll Robertson pupil is found in only 18% of cases of_____, abnormal pupils are found in 80% of the cases. The diagnosis of neurosyphilis requires a good history, physical examination, and laboratory tests.
neurosyphilis
may occur several months after a traumatic third-nerve palsy and is characterized by a pseudo-Argyll Robertson pupil,
Aberrant regeneration of cranial nerve III
Is a commonly used test for stereopsis. The test consists of a booklet containing polarized test stimuli for use at a 40-cm testing distance and requires the use of cross-polarized lenses. The test includes a stereofly, which serves as a gross test for stereop-sis, producing approximately 3000 seconds (almost 1 degree) of retinal disparity at the 40-cm testing distance.
The stereofly is a particularly good test of stereopsis for preschool children. The child is asked to reach out and touch the fly’s wings, which should appear to be located at some distance above the booklet. If the child’s fingers touch the booklet when attempting to touch the wings, not even gross stereopsis is present.
The Titmus Stereotest
like the ‘litmus Stereotest, is a polarized test providing stimult for both gross and fine stereopsis testing, The test has the advantage that the examiner can make the reindeer’s nose wiggle by rotating the picture slightly.
The Bernell Stereo Reindeer test
consists of a demonstration plate and two test plates. The demonstration plate contains a raised letter E that can be seen by anyone who has reasonably good acuity, and it requires no stere-opsis. Each of the test plates is printed with a polarized random dot pattern and requires the use of Polaroid glasses, A patient who has stereopsis will see a raised letter E in the random dot pattern of one of the test plates, whereas the other test plate will be seen as a blank.
The Random Dot E test
A test of color vision should be a part of every basic optometric examination. In testing children, the main concern is the detection of congenital red-green color vision anom-alies, and any pseudoisochromatic plate color test is satisfac-tory.
In testing adults, the practitioner should be concerned with the possibility of an acquired color vision anomaly, so the patient should be screened for both red-green and blue-yellow anomalies, and each eye should be tested separately.
Normal color vision is said to be____, because a person with normal color vision requires three primary colors to match any given color stimulus.
Trichromat
The trichromatic subject will repeatedly use the same proportions of the three primary colors to match a given color sample. An anomalous trichromat requires three primaries, just as the normal trichromat does, but will match a given stimulus with different proportions of the three primaries.
An anomalous trichromat may be either protanomalous (red-weak) or____ (green-weak).
deuteranomalous
____is an individual who requires only two primaries to match any given color stimulus. A ____ may be either a protanope (red-deficient) or a deuteranope (green-deficient).
dichromat
Undoubtedly the most effective procedure for color vision testing involves the_____. With this instrument it is possible not only to detect the presence of a red. green color vision anomaly but also to make a differential diagnosis. The main problem with this instrument is its relatively high cost–not many practitioners are willing to make a major investment in an instrument designed to test for a condition that cannot be treated.
Nagel anomaloscope
Pseudoisochromatic plates are by far the most popular of all color vision tests. The test is in the form of a book containing a number of color plates, each plate containing a number, a figure, or in some cases an irregular winding path. Each figure is made up of____ that vary from the background in____ as well as brightness.
dots
hue
The______, also known as the dichotomous test, is a useful, quickly performed test designed to sort people into those who are color-normal and those with color vision anomalies (Figure 7-24). The test is made up of 15 color samples, and the patient’s task is to line them up so that they form a smooth color sequence between the two fixed samples at the ends of the tray.
Farnsworth D-15 test
Visual field defects in glaucoma are the result of nerve fiber-bundle lesions. As shown in Figure 7-26a, the retinal ganglion cell fibers, traveling to the optic nerve head from the individual ganglion cells, are of three types: (1) the papil-lomacular bundle, made up of fibers from ganglion cells in the macular region; (2) the radial fibers, from the ganglion cells of the nasal portion of the peripheral retina; and (3) the arcuate fibers, from the ganglion cells in the temporal portion of the retina.
may be manifested either as a bilateral central scotoma-as in tobacco amblyopia, alcohol ambly. opia, nutritional amblyopia, lead poisoning, or digitalis toxicity-or as peripheral depression or contraction- as in poisoning by quinine, arsenic, chloroquine, or salicylates (Figure 7-27a). The scotoma of tobacco or alcohol ambly. opia may be a centrocecal scotoma, involving both the fixation arca and the arca surrounding the blind spot.
Toxic amblyopia
. Inflammation of the optic nerve may occur in the form of ____ (inflammation of the optic nerve head) or_____(inflammation of the optic nerve behind the eye). Either condition tends to cause a central scotoma with or without peripheral depression.
Papillitis
retrobulbar optic neuritis
If the optic nerve inflammation is due to multiple sclerosis, there may be a____ (a scotoma of which the patient is aware). Papilledema, an elevation of the optic nerve head due to increased intracranial pressure, tends to cause visual field losses only in the later stages, and these field losses are usually permanent.
transient positive scotoma
Tumors or other disease processes affecting the optic chiasm are more likely to affect the crossing fibers than the noncrossing fibers and, therefore, tend to cause temporal field loss for each eye (___). In some types of pituitary tumors, the field loss begins in the upper temporal fied and progresses (clockwise for the right eye and counterclockwise for the left eye) into the lower temporal field and, finally, into the lower nasal and upper nasal fields.
bitemporal hemianopsia
The great majority of visual field defects begin in the central visual field (i.e., within______ of fixation) or can be found in the central field at a relatively early stage.
30 degrees
can be detected quickly and easily by using a peripheral field screening pro cedure known as confrontations. Therefore, the optometrist’s preliminary examination should include both central and peripheral field screening procedures.
hemianopic field defects
This instrument which was one of the first automated visual field screening instruments to be introduced, has been described by Johnson and Keltner (1980a, 1980b), It has a uniformly illuminated white hemispherical field with 99 holes, cach of which can be iliuminated by a fiber-optic element.
Each spot is illuminated in a programmed, randomized sequence, using a method referred to as supra-threshold static perimetry,
The Synemed Fieldmasted
as performed by the Schiotz tonometer, is a convenient and easily performed method of tonometry, but in recent years it has been superseded to a great extent by applanation tonometry.
Indentation torometry,
