Certified Paraoptometric (CPO) - Unit III Questions and Answers

Visual Acuity (VA) - Answer- The meausure of the finest detail the eye can detect. Typically described as a Snellen fraction. Snellen Letters - Answer- Letters most often used to measure acuity at distance. Snellen Fraction (20/20) - Answer- = Testing Distance / Distance at which letter is standardized to be read Snellen numerator - Answer- Testing distance (usually 20 feet) Snellen denominator - Answer- Distance at which the letter is supposed to be read. Cover/Uncover/Alternative-Cover Testing - Answer- Examines the binocular relationship of the eyes. The patient is asked to fixate on a distant object (or near) while their eyes are observed. Exotropia - Answer- One eye fixating while the other deviates outward. Esotropia - Answer- One eye fixating while the other deviates inward. Hypertropia - Answer- One eye fixating while the other deviates upward. Keratometry/Ophthalmometry ("K-reading") - Answer- Measures the curvature and focusing power of the cornea. Allows you to estimate the focusing power of the cornea, the amount of astigmatism present, and give an evaluation of the integrity of the front surface of the eye. Used in estimating CL base curve. Topography - Answer- Basis lies with Placido disk technology. Precisely analyzing the radius of the curvature and the refractive power at thousands of points across the cornea. It assists with evaluating refractive problems in the cornea and is an excellent tool for refractive surgery (pre-op & post-op). Retinoscopy - Answer- An objective measure of the refractive power of the eye. Examiner shines the light into the patient's eye and observes the reflex seen in the patient's pupil. The concept is based in movement of the reflex and finding the lens that will stop that movement (neutralizing it). Manifest/Subjective Refraction - Answer- Uses the patient's responses to determine the best correction. An instrument containing lenses is used to determine the spectacle correction. Phoropter - Answer- The instrument that contains lenses and can be used to determine a spectacle correction. Ophthalmoscope - Answer- An instrument that illuminates and inspects the interior of the eye (direct or binocular indirect). Ophthalmoscopy - Answer- The examination of the inside of the eye. Direct Ophthalmoscope - Answer- Hand-held instrument that yields a larger image than its counterpart, but a smaller field of view. This instrument provides more magnification and a narrower view. Binocular Indirect Ophthalmoscopy (BIO) - Answer- Instrument worn on the examiner's head, uses a hand-held lens, and yields a much smaller image and a much larger field of view than its counterpart. Requires the use of dilation drops to get a better view of the interior of the eye. Binocular Vision - Answer- The ability of the two eyes to work together as a team. Vision is typically enhanced when viewing the world binocularly. Tonometry - Answer- Test used to measure the intraocular pressure (IOP) in the eye. Two different instruments/methods are used to measure this; one relies on anesthetic drops. Goldmann Tonometry - Answer- Standard test for IOP accuracy. Instrument has a small plastic probe and is mounted on a slit lamp biomicroscope. Fluorescein and anesthetic drops are required because the instrument needs to touch the cornea to get a reading. Non Contact Tonometry (NCT) - Answer- Very common device used to measure IOP. This device sends a puff of air against the eye to measure the pressure within. Visual Fields - Answer- The area in space that is visible to the eye. The test to measure this requires patients to report when they see targets with their peripheral vision while they're looking straight ahead. This test can be performed manually or be automated and can help differentiate what type of disease a patient may have. Photophobia - Answer- Increased sensitivity to light. Perimetry - Answer- Test used to measure the visual field. Automated Perimetry - Answer- Zeiss, Humphrey, Dicon, or Octopus machine used to measure the visual field. Confrontation Fields - Answer- Manual perimetry used to measure the visual field. Biomicroscopy (Slit lamp exam) - Answer- Performed as part of the ocular health examination. Gives the examiner a highly magnified view of the structures of the eye, including the eyelids and lashes. It's like a microscope mounted sideways. Used for observing the fit of CLs, checking for foreign bodies in the eye, and looking at all parts of the front of the eye. Fundus Photography - Answer- The creation of a photograph of the interior surface of the eye by focusing light through the cornea, pupil, and lens. Needed to document the health of the optic nerve, vitreous, macula, retina, and its blood vessels. Fundus - Answer- Interior posterior surface of the eyeball. Posterior Pole - Answer- Refers to the retina between the optic nerve and macular area. Arcades - Answer- Normal pattern of retinal blood vessels as they leave the optic nerve head and arch around the macula. Cup-to-Disc Ratio (C/D) - Answer- Numerical expression indicating percentage of disc occupied by the optic cup. Exudates - Answer- Protein or fatty fluid that leaks from blood vessels into retinal tissue (hard is less fluid, more dense) (soft, fluffy looking; also called cotton wool spots). Cotton Wool Spots - Answer- Fluffy looking white deposits resembling small tufts of cotton within the retinal nerve fiber layer that represent small patches of retina that have lost their blood supply from vessel obstruction. Nevus - Answer- A mole; small and flat usually pigmented area; benign tumor made of specific cells (with the same name) found in the skin and eye tissue. Pachymetry (with pachymeter) - Answer- The measurement of the thickness of the cornea. Useful in monitoring the progression of certain disorders that cause the cornea to become thickened (or filled with water), resulting in vision loss. Also used to determine if the cornea is thick enough for refractive surgery procedures. Lensometer (auto or manual) - Answer- Instrument used to measure sphere, cylinder, axis, and prism in lenses (power of spectacle lenses and contact lenses). Optical Coherence Tomography (OCT) - Answer- A laser-based, non-contact, non-invasive imaging technique that is capable of obtaining high-resolution images of the retina and its components. Refractive Status - Answer- Describes how light rays that enter the eye are focused. Optical Infinity - Answer- Where light rays go parallel at 20 feet.. Myopia (nearsightedness) - Answer- Usually caused by the eye being too long. While viewing a distant target with accommodation relaxed, the image is focused on the front of the retina resulting in blurry distance vision. This is corrected with a minus lens. Hyperopia (farsightedness) - Answer- This can result because the cornea is too flat, or because the eye is too short. While viewing a distant target with accommodation relaxed, the image is focused behind the retina resulting in blurry vision. Accommodation can make up for some of the refractive error. This is corrected with a plus lens. Astigmatism - Answer- While viewing a distant target with accommodation relaxed, the image is not focused at one point but at two points. This results because the cornea is longer in one meridian than the other (football-shaped). Presbyopia - Answer- The loss of the ability to see clearly at near distance, caused by the crystalline lens losing its ability to change shape, or accommodate. In most patients, symptoms begin in the early 40's and continue until the mid 60's, when the lens in the eye completely loses its ability to bend. Treated with reading glasses, progressives, or monovision. Contact Lenses (CLs) - Answer- A corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye. Daily Wear Contact Lenses - Answer- CLs applied after waking and removed before sleep; not designed to be on the eye during sleep. Extended Wear Contact Lenses - Answer- CLs approved for wearing 24-hours, and includes sleeping with lenses on the eye. Available for continuous wear, or overnight, for a range of 1 week to thirty days. Replacement Schedule - Answer- Disposable CLs are to be discarded according to a prescribed schedule. They may be discarded after one day, one week, or two weeks after starting routine wear. Frequent replacement lenses are lenses that are only used for a specified period of time, such as one month or three months. Soft CL - Answer- Lenses made from polymers or materials that absorb water, similar to a sponge. Rigid ("hard") CL - Answer- At one time these lenses were made from a material known as polymethylmethacrylate (PMMA). This material did not allow oxygen to flow through to the cornea, resulting in edema. Gas-Permeable (RGP) CL - Answer- Rigid lenses now made from polymers and plastic materials that are oxygen-permeable. Last longer and provide sharper vision than soft CLs. Parameter Defined - Answer- Soft CL meas