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What are visual fields?
entire area seen by an eye when it looks at a central point.
What are visual pathways?
- For an image to be seen, light reflected from it must pass through the pupil and be focused on sensory neurons in the retina.
- The image is projected there is upside down and reversed right to left.
Ex: An image from the upper nasal visual field thus strikes the lower temporal quadrant of the retina.
What are pupillary reactions?
Pupillary size changes in response to light and the effort of focusing on a near object
What is the light reaction?
- Direct reaction: light shine in one retina, that one pupil constrict
- Consensual reaction: light shine in one retina, and both pupil constrict
What is the near reaction?
when a person shifts gaze from a far object to a near object ( 10 cm from the eyes), the pupils constrict
What is convergence of the eyes?
extraocular mvt that happens during the near reaction - eyes come together internally, object 5-8 cm from nose
what is accomodation?
- lenses change shape due to the contraction of the ciliary muscles.
- This change in shape of the lenses brings near objects into focus but is not visible to examiner.
In the activation of which nervous system does pupillary constriction occur?
Parasympathetic nervous system ( rest and digest)
How are extraocular muscles tested?
- - through the corneal light reflexion
- - practitioner
What are extraocular mvts?
mvt of eye in 6 cardinal points
How are extraocular muscles tested?
- - through corneal ligh reflex
- - practitioner stands 2 ft away from patient shining light onto pt's eyes
- - Light should be visible slightly nasal to center of pupils
Sudden visual loss may be associated with 3 conditions, what are they?
- retinal detachment
- vitreous hemorrhage
- occlusion of the central retinal artery
What is presbyopia/ hyperopia?
difficulty with close vision
What is myopia?
difficulty with far vision
What are scotomas and when are they seen?
They are floaters that suggest lesions in the retina or visual pathways
What do flashing lights indicate?
detachment of the vitreous from the retina : EMERGENCY
Where does diplopia come from?
- lesion in brainstem and cerebellum or
- from weakness of paralysis of one or more extraocular muscles
How is visual acuity tested?
using the Snellen chart
How is the Snellen score determined?
stop at smallest line of print which the patient can identify more than half the letters
What does 20/200 mean?
the patient can see at 20 ft what the normal eye can see at 200 ft
If the patients cannot read the largest letter what should the NP do?
test ability to count upraised fingers and distinguish light ( such as flashlight) from the dark.
In the US, when does a person is considered legallly blind?
- when vision in the better eye corrected with glasses is 20/200 or less.
- Or from a constricted field of vision 20 degrees or less in the better eye.
Why and how are visual fields tested?
- Test is done to detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma,stroke, brain tumours or other neurological deficits.
- Test (by confrontation) : wiggle fingers in upper, central and lower temporal quadrants, and patient says when they see fingers
If a defect is found what should the practitioner do?
- - test 1 eye at a time
- - cover good eye, and repeat test on suspected eye.
What is hemanopsia?
when pt repeateadly does not see finger until they have crossed the line of gaze. ( vision fields by confrontation)
What is anisocoria?
pupillary inequality of < 0.5 mm
During the ophtalmoscopic examination, the PCP should have to dilate the pupils, but what are some cases what would require him/her to do so?
- - see more peripheral structures
- - better examination of the macula ( responsible for central vision)
- - investigate unexplained visual loss
What is used to dilate the pupils?
What are some c/i to dilating pupils?
- - head injury and coma ( continuous monitoring of pupil reaction in necessary)
- - any suspicion of narrow angle glaucoma
What does absence of the red reflex mean?
opacity of the lens ( helps focus light on the retina) - cataracts
What is ptosis and in what condition is it seen?
- drop of the upper lid
- Seen in: myasthenis gravis, damage to the oculomotor nerve, Hoerner's syndrome ( damage to the sympathetic nerve supply)
- may also be congenital
In what condition are retracted lids and a lid lag seen?
What is seen in exophthalmos and with what condition does it come?
- eyeball protrudes forward
- Graves disease/ hyperthyroidism
When is epicanthus fold seen?
- - normal in asian people
- - Downs
What is ectropion and when is it seen? - with what age group is it more common?
- margin of the lower lid is turned outward --> eye no longer drain satisfactorily and tearing occurs.
- more common in the elderly
- silver circle around pupils
What is an entropian and with what population is it seen the most?
- inward turning of the lid margin
- in order too see it well, ask pt to squeeze the lids together and then open them
What conditions can cause preorbital edema?
- local inflammation
- fluid retaining states such nephrotic syndrome
In what population does herniated fat under the eye appear?
What is a sty? ( acute hordeolum)
- painful, tender infection at the eyelid
- looks like a pimple on the lid margin
SS of a chalazion?
- painless nodule inside the lid.
SS of xanthelasma?
- raised, yellowish plaque appearing along the nasal portions of one or both eyelids
- may accompany lipid disorders
SS of uveitis? (most common: inflammation of iris)
- Location: margin of the limbus
- Visual acuity: decreases in affected eye
- EOM mvt mornal
- Bilateral photophobia
What are the SS of conjunctivitis? (Pain, vision, d/c, pupil, cornea, significance)
- infection of the conjunctiva : dilation of conjunctival vessels with redness that maximizes in the periphery
- Pain: Mild discomfort
- Vision: not affected except mild blurring due to d/c
- D/c: watery, mucoid, or micropurulent
- Pupil: not affected
- Cornea: clear
- Significance: bacterial, viral, allergy, irritation, other infections
What are the SS of corneal injury or infection? (Pain, vision, d/c, pupil, cornea, significance)
- Pattern of redness: ciliary infection - eyes may be diffusely red
- Pain: moderate to severe
- Vision: usually decreased
- D/c: watery or purulent
- pupil: not affected unless iritis
- Cornea: changes depending on cause
- Significance: abrasion, bacterial, viral infections, other injuries
What are the SS of glaucoma? (Pain, vision, d/c, pupil, cornea, significance)
- Pain: severe, aching, deep
- Vision: decreased
- D/c: absent
- Pupil: dilated and fixed
- Cornea: steamy, cloudy
- Significance: Acute increase in intraocular pressure - EMERGENCY
What are the SS of subconjunctival hemorrhage?(Pain, vision, d/c, pupil, cornea, significance)
- Pattern of redness: leakage of blood outside of the vessels, producing a homogenous, sharply demarcated, red area that fades over days to yellow and then disappears.
- Pain: absent
- Vision: not affected
- d/c: absent
- Pupil: not affected
- Cornea: clear
- Significance: often none, may result from trauma, bleeding disordwers, or a sudden increase in venous pressure as from cough.
What is corneal arcus?
- thin grayish white circle close to the extremity of the cornea
- often seen in elderly and AA
What is a corneal scar?
- superficial grayish white opacity in the cornea secondary to inflammation or old injury
SS of pinguecula?
- yellowinsh nodule in the bulbar conjunctiva on either side of the iris
- appears often with aging, 1st on the nasal and then on the temporal side
What is pterygium?
- triangular thickening of the bulbar of the conjunctiva that grows slowly across the outer surface of the cornea, usually from nasal side.
- may interfere with vision.
- caused by dust and sunlight
What are cataracts?
- opacity of the lens seen through the pupil.
- Common cause: old age
- Treatment: replace lens
- 2 types:
- - nuclear cataracts: looks gray when seen by flashlight - through ophtalmoscope, cataract looks black against the red reflex.
- - Peripheral cataracts: produces spoke like shadows that point inward. - gray against black as seen with a flashlight - or black against red with an opthalmoscope
Seeing is like looking through a fogged window.
What are tonic pupils? (PEERLA?)
- tonic pupil is large, regular and usually unilateral
- reaction to light: reduced, slow or sometimes absent
- Near rxn: very slow but present
- slow accomodation causes blurred vision
- DTR dec.
- affected pupil react briskly to light and near effort.
- ptosis of the eyelid
Equals pupils and one blind eye?
- when light is shine on blind eye, no reaction
- when light is shine on good eye, pupil restrictions occur in one and both pupils.
What is strabismus? SS and treatment?
- deviation of the eyes from their normally conjugate position
- corneal reflections are asymmetric
- Test: cover -uncover test - for example if right eye is weak, left eye is covered, right eye will fix at light, left eye is uncovered, left eye will look at light, while right eye moves back inward
- Treatment: patch the good eye, to work the muscles of the bad eye
- Found in children at the age of 3
What is the difference between paralytic and non paralytic strabismus?
- Paralytic: deviation varies depending of direction of gaze - low muscle tone
- Non-paralytic: the deviation is constant in all directions of gaze - CN paralysis
What is the difference between convergent ( Esotropia) and divergent ( exotropia) strabismus ?
- Esotropia: eye moves inward
- Exotropia: eye moves outward
What are cotton-wool patches and when are they seen?
- white and grayish ovoid lesions with irregular borders in the retina - smaller than the disc
- result from infarcted nerve fibers due impairment of blood supply to that area.and are seen with HTN, diabetes and many other conditions.
Difference between close angle and open angle glaucoma?
- Open angle:
- - caused by slow clogging of the dranaige canals --> inc. eye pressure
- - develops slowly and is a lifelong condition
- - symptoms and damages are not noticeable
- Close angle:
- - blocked drainage canals --> sudden rise in IOP
- - dvlps very quickly
- - symptoms and damage are noticeable
- - EMERGENCY
What is AV nicking and when is it seen?
- AV nicking is seen in HTN, and it is when the narrowed arteries ( due to HTN) create identations in the veins and cross them.
- htn retinopathy
SS of retinal detachment
- Sign: absence of red reflex
- Symptoms: loss of partial vision, shade coming down
Color vision testing -
What is considered normal?
What tool is used for the exam?
How is it recorded?
- Normal: red, blue, green sensitive
- Ishihara plates
- No more than 4 errors - is ok!
Why is fluorescein stain used?
- corneal abrasion
- Dendritic ulcer: herpes simplex colonizes trigeminal ganglion --> keratitis
SS of diabetic retinopathy?
- DR is damage to the blood vessels in the retina - may cause blindness
- Fluid can leak to the macula and make it well --> central vision is affected
SS of papilledema?
- optic disc swelling that is caused by increased ICP
- usually bilateral
- may have blurry in vision, and eventually vision loss
- Treat root cause ( ICP)