Eye Overview and Introduction to the Eye Exam - Graf and Eye Surgeries - Kugler Flashcards
define: Emmetropia:
Visual condition in which an infinitely distant fixated object is imaged sharply on the retina (without an accommodative response)
What vision does this diagram represent?
Emmetropia
Refraction:
Altering of the pathway of light from its original direction, result of passing from one medium to another
Ametropia:
Refractive condition in which parallel rays do not focus on the retina; a deviation from emmetropia (abnormal vision)
define Myopia:
Refractive condition in which parallel rays of light entering the eye, focus in front of the retina; nearsightedness
Corrected using LASIK surgery
What vision does this diagram represent?
Myopia
Lenses for myopia
- Minus
- Concave
- Diverging
define Hyperopia:
Refractive condition in which parallel rays of light entering the eye f_ocus behind the retina_; farsightedness
What vision does this diagram represent?
Hyperopia
Lenses for hyperopia
- Plus
- Convex
- Converging
define: Astigmatism
Refractive condition in which rays emanating from a single point are focused as two line images (blurry vision at all distances), generally at right angles to each other; due to unequal refraction of the incident light in different meridians
Eye becomes astigmatic when any of its refracting surfaces assumes a toroidal shape
Eye is not perfectly round (ex: football shaped not basketball shaped)
What type of asitgmatism is this?
compound myopic astigmatism
What type of astigmatism is this?
Compound hyperopic astigmatism
What type of astigmatism is this?
Mixed astigmatism
define Presbyopia:
Reduction in accommodative ability occurring normally with age and necessitating a plus lens addition for satisfactory seeing at near
Amplitude decreases from childhood to age 75
Presbyopia
affects 100% of people
treat with reading glasses
corrected surgically using: Conductive Keratoplast or Scleral Spacing Procedure (FDA trial)
define Accommodation:
Ocular adjustment for vision at various distances, by changes in shape (steepening) of the crystalline lens
define Diplopia:
Condition in which a single object is perceived as two objects rather than as one; double vision
- usually results from EOM imbalance
- monocular: persists when fellow eye is covered
define: Anisometropia:
Condition of unequal refractive state for the two eyes, one eye requiring a different lens correction from the other
Six Elements or Major Categories of Eye History
- chief complaint
- medical history
- medications/ hypersentitivities
- visual and occular history
- last eye exam
- galsses or contacts
- family eye and medical history
- cataracts, glaucoma, macular degneration
- vocational and recreational demands
VISUAL Symptoms of Ocular Discomfort
- Blurred vision
- Diplopia
- Distortion
- Vertigo
- Glare/light sensitivity
- Spots before eyes
- Light flashes
- Loss of vision
- Halos around lights
- Loss of visual field
- Night blindness
- Movement of field
OCULAR Symptoms of Ocular Discomfort
- Itching or burning
- Tenderness, soreness
- Pain, foreign body sensation
- Excessive lacrimation
- Change in blink rate
- Warm, hot, tired feeling
- Twitching of lids
- Mattering of eyelids
REFERRED Symptoms of Occular Discomfort
- Headache
- Fatigue
- Stress
Physical Exam
Visual Acutiy: Snellen
Pupils: size, shape, equality; reaction to light (PERRLA)
Extra-ocular muscles: movements of eyes into 6 cardinal positions (H test)
Visual field: confrontation testing
Anterior Segment Exam: slit lamp or pen light look at - lids, lashes, lacrimal gland, cornea, conjuntiva, iris, lens
Direct Ophthalmoscopy: media - cornea, lens, vitreous, disc, macula, vessels
Physical Exam: Visual Acuity
- Patients will usually get some letters correct and some incorrect as the letter size approaches their threshold
- Non-conventional methods: Near/Tumbling E/Pictures
- Pg. 66 Mosby’s Record line in which they miss NO letters….(Evan)
Four Cardinal Eye Complaints
- Changes in Vision
- Changes in Appearance
- Pain or Discomfort
- Trauma
Cardinal Changes: Change in Vision
- Painless or Painful
- Extent of Vision Loss
- One or Both Eyes:
- Bilateral: neurologic etiology, not a primary problem
• Flashes or Floaters
- Multiple – retinal tear, vitreous hemorrhage
- Single – benign
• Rate of Onset
- Rapid deterioration: vascular cause
- Gradual loss: cataracts
Cardinal Changes: Pain or Discomfort
- Pain or no pain?
- Foreign body sensation
- Excessive tearing
- Itching or burning
- Light sensitivity
Cardinal Changes: Trauma
- Tetanus immunization state
- Fluid or chemical exposure
- Blunt or penetrating injury
Special Tests: Sit-Lamp Examination
Highly magnified views of: anterior segment and posterior segment
Special Tests: Intraocular Pressure
Analogous to systemic blood pressure
IOP – 8 to 21 mm Hg
Glaucoma screening
Emergent Conditions (immediate referral)
o Sudden Vision Loss
o Retinal Artery Occlusion
o Chemical Burns
o Acute Angle-Closure Gluacoma
Urgent Conditions
(referal with 1 day or less)
o Acute glaucoma
o Orbital cellulitis
o Hyphema
o Corneal Ulcer
o Retinal Detachment
Implantable Collamer Lens (ICL)
used in patients who cannot have lasik (too nearsighted)
in surgery - cut the limbus, insert the ICL next to the patient’s lens
Occular Maturity
often occurs at age 18
vision change of less than +or- 0.75 within 1 year
Cataract
natural clouding (or darkening) of lens
age dependent
typically affects older adults (60+), can occur in infants or children - rarely
Leading cause of preventable blindness world wide
Cataract Surgery
Entry Incision
Capsulorhexis (cutting the lens)
Phacoemuslification (use ultrasound to destroy lens)
Lens placement (standard, multifocal, accomodative lens types)
Corneal Arcuate Incisions (correct astigmatism if needed)
Keratoconus
Cone-shaped cornea
Progressive blinding disease
No good treatment - corneal transplant, Collagen Cross-Linking (Clinical Trial)
