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-Pictures are most eagerly received and more likely to be useful
-The greatest distance at which three of the pictures are accurately recognized by each eye is recorded as the numerator of a 30-foot denominator
-Comparison of the visual acuity of the two eye is more important than absolute values
2-3: 12-15 ft
3-4: 15-20 ft
Adults: 30 ft
*Difference of 5 ft between two eyes: referral

<2 years: Flashing a light into each eye consecutively
-Able to fixate on light centrally and steadily, vision may be assumed as normal
-An infant should follow light by the age of 3 months and reach for toys by the age of 4-6 months

1) Whenever there is doubt about the child's motivation, intelligence, or attention, the E game should be used.
2) A false idea of visual acuity will be obtained if an isolated letter is presented to the patient rather than a line of letters.
3) There can be differences in recognition of letters in the same line.
4) Vision should always be tested with and without glasses.
5) In children, visual acuity testing should not be prolonged and fatiguing.
6) The child who cannot comprehend the organization of the E game should receive practice at home.
7) In all visual acuity measurements, the assistant should note any consistent pattern in the letters missed by the patient.
8) If both eyes are tested together, it is usually found that each eye reinforces the other.
9) A false visual acuity will be obtained if the patient partially closes an eye or squints.
10) The patient should be observed during testing to prevent peeking around the occluder.
-Ultrasound is an indispensable tool in medical imaging and plays an important role in ophthalmologic diagnoses
-Most important imaging technique in eyes with anterior segment opacities
-Mechanical waves and vibrations occur over a wide range of frequencies called the acoustic spectrum
-The frequency most commmonly used in ocular imaging is 10 MHz; higher frequency = loss of penetration
-All human tissues exhibit ultrasound attenuation coefficients that increase with frequency
-Electrical impulses are converted to sound by a vibrating transducer
-Propagated through tissues at various speeds and are reflected or scattered from interfaces between tissues of different acoustic impedance (a property related to the density of the tissue and the speed at which sound passes through it)
-Transducer "waits" and initiates reverse process

A-scan: single linear image
-The longer it takes an impulse to return, the farther it is placed on the display
-The height of the spike on the graph relates to the intensity of the returned echo

B-scan: produced by a moving transducer
Two-dimensional cross-sectional representation
-At each point along the path, pulse sent out and received
-Intensity of returning sound is represented on the screen as brightness instead of height on a graph
-Easier to interpret than an A-scan
-Used for most diagnostic work, such as determining the state of the retina behind an opaque cataract or imaging intaocular tumors

-A-scan also used for diagnosis but is harder to interpret
-Axial length: distanc ebetween the corneal surface and retinal surface
-The best way to reduce occupational risk of "bloodborne" infection is to follow universal precautions based on the concept that every patient should be treated with the same level of precautionary and preventive measures to ensure the safety of everyone involved, including health care personnel
-From Occupational Safety and Health Adminstration (OSHA)

1) Wash hands before and after patient contact, and immediately if hands become contaminated with blood or other body fluids.
2) Wear gloves wherever there is a possibility of contact with body fluids.
3) Wear masks whenever there is a possibility of contact with body fluids via airborne route.
4) Wear gowns if exposed skin or clothing is likely to be soiled.
5) During resuscitation procedures, ensure that pocket masks or mechanical ventilation devices are readily available for use.
6) Clean spills of blood or blood-containing body fluids with a solution of household bleach and water in a 1:100 solution for smooth surfaces and 1:10 solution for porous surfaces.
7) Health care professionals who have open lesions, dermatitis, or other skin irritations should not participate in direct patient care activities or handle contaminated equipment.
8) Contaminated needles should never be bent, clipped, or recapped. Immediately after use, contaminated sharp objects should be discarded into a puncture-resistant "sharps" contained designed for this purpose.
9) Contaminated equipment that is reusable should be cleaned of visible organic material, placed in an impervious container, and returned to central hospital supply or some other designated place for decontamination and reprocessing
10) Instruments and other reusable equipment used in performing invasive procedures should be disinfected and sterilized as follows:
-Enter the patient's vascular system or other normally sterile areas of the body: sterilized before being used for each patient.
-Touch intact mucous membranes, but do not penetrate body surfaces: sterilized when possible or undergo high-level disinfection
-Do not touch patient or touch intact skin: cleaned with detergent
11) Body fluids to which universal precautions always apply are as follows: blood, serum/plasma, semen, vaginal secretions, cerebrospinal fluid, vitreous fluid, peritoneal fluid, amniotic fluid, and wound exudates
12) Body fluids to which universal precautions apply only when blood is visible: sweat, tears, sputum, saliva, nasal secretions, feces, urine, vomitus, and breast milk
1) Set the image capture software to record for fluorescein angiography. This sets the camera and computer to process the image in black and white and raises the ISO setting because the fluorescein filters absorb a lot of light
2) Set the flash intensity to the level used for color photography
3) Introduce the green or "red free" filter into the light path
4) Position the patient at the camera and take a stereo photograph of the area to be studied with the green filter in place
5) Set the image software and camera to its fluorescein angiography settings. This may automatically increase the flash output to the level required, or you may have to change the settings manually
6) When the needle is correctly inserted into the patient's vein, check the patient's head position and viewing through the camera's viewfinder, to again ensure proper alignment and focus
7) Initiate the rapid injection of the fluorescein and simultaneously activate the timer
8) At 5-7 seconds following the start of the injection, the exposure sequence should commence.
Arm-to-eye circulation in adults: 8-15 seconds, 4-7 seconds in a child
9) After the rapid-sequence documentation of the initial circulation of fluorescein through the full arteriovenous phase, the frequency of exposures can be reduced considerably because further development in the angiographic pattern occurs more slowly beyond this point
10) Intermediate or recirculation phase: photographs should be taken at approximately 1-3 minutes after injection
11) A late photograph, approximately 8 minutes after injection, is also recommended. Certain conditions ae not delineated until this point
-Healthy recocognition of the imporance of autonomy: the right of people to make their own decisions about what they will and will not allow
-Informed consent represents a partnership between medical professionals and their patients
-Doctors have a fiduciary duty to ensure that each patient understands the treatment recommendations
-The obligation of the physician remains to at least attempt to demonstrate that the patient does indeed have some comprehension of the meical plan
-More than just a signed paper "consent form"; process, documented in the patient's health record wherein the physcian or trained delegate educates the ptient and asks for his/her participation in the decision-making process
-If the medical encounter is to involve aspects of risk, in particular risks of bodily harm as in surgery of laser treatment, then formal informed consent, preferably documented by the patient's signature, is required
-The eye doctor must infor the patient of all common risks, no matter how small (including those that might result not only in changes in function but also appearance), and also serious risks, no matter how uncommon.
-Comprehension is another foundation of informed consent. Patients may refuse treatment, even if their decision will result in death or blindness if they are deemed to have the capacity to do so
-If the decision-making capacity of the patient is in question, a substitute decision maker must be found
-Even when the patient is deemed capable, the ophthalmologist must ensure that the necessary information for decision making is presented in an understandable way.
-The patient must be given the opportunity to ask questions and receive answers before making a voluntary decision without influence or coercion.