Ординатура / Офтальмология / Английские материалы / Quick Reference Dictionary of Eyecare Terminology 4th edition_Ledford, Hoffman_2005

174 ptosis/punctal plug

ptosis: In ophthalmic usage, a drooping of the upper eyelid; also called blepharoptosis; p. adiposa ptosis caused by the deposit of fatty tissue in the upper eyelid; apparent p. the lid appears to be ptotic, but in actuality it is not (eg, in hypotropia the elevated eye is more covered by the upper lid, causing the optical illusion that the lid is lower); false p. another term for pseudoptosis; guarding p. tendency of the lid to droop when the eye has been injured in some way; Horner’s p. ptosis accompanied by miosis and lack of sweating on one side of the face, caused by a nerve defect; see also Horner’s syndrome; levator p. ptosis caused by a defect of the levator muscle; mechanical p. ptosis caused by a mass or scar tissue that prevents the lid from rising fully; morning or waking p. normal drooping of the upper eyelid noted upon waking from sleep; neurogenic p. ptosis caused by nerve palsy; pseudop. apparent drooping of the eyelid that is actually a result of an abnormally narrow fissure; also called false ptosis.

pulsed phaco power: Phacoemulsification instrument setting in which ultrasound power is automatically switched on and off rapidly so that the needle is alternately vibrating and stationary; used to prevent heat build-up of the metal phaco tip; see also duty cycle.

puncta: Plural of punctum.

punctal occlusion: 1. Method for treating dry eye syndrome by blocking the outflow of tears through the puncta, either temporarily by inserting a punctal plug or permanently by laser cauterization; 2. method of keeping eye drops on the eye and out of systemic circulation by applying pressure to the nasal canthus (with the fingers) after medication has been instilled.

punctal plug: Device that is designed to be inserted into (and later removed from) the punctum in order to treat dry eye by blocking the outflow of tears.

punctum: In ophthalmic usage, one of the openings in the eyelids through which tear fluid drains off of the eye; there is one in the upper (ie, superior p.) and the lower (ie, inferior p.) of each lid, located 2 to 4 mm from the medial canthus; plural: puncta.

pupil (P): Normally circular opening in the center of the iris that controls the amount of light passing through the eye to the retina by opening (dilating) in dim light in a process called mydriasis and closing (constricting) in bright light in a process called miosis; for a number of unusual states and abnormal conditions of the pupil that are noteworthy, see also Adie’s p., Argyll Robertson p., Behr’s p., cat’s eye p., keyhole p., and Marcus Gunn p; fixed p. pupil in which there is no reaction to light or near; tonic p. pupil in which the near reaction of miosis is stronger than the miosis caused by direct light; usually referring to Adie’s p.

pupillary axis: See axis.

pupillary block: Condition in which the iris presses against the structures behind it, blocking the normal flow of aqueous humor into the anterior chamber and resulting in a build-up of intraocular pressure; see also iris bombé and pupillary block glaucoma under glaucoma.

pupillary dilator muscle: Iris muscle encircling the outer edge of the iris and extending into the ciliary body, responsible for dilating the pupil; compare pupillary sphincter muscle.

pupillary distance (PD): Measurement of the distance from one pupil’s nasal edge to the temporal edge of the pupil of the fellow eye; the idea is to figure the distance between the eyes’ visual axes; also called interpupillary distance (IPD).

pupillary margin: Heavily pigmented edge of the iris immediately surrounding the pupil.

pupillary muscle: See pupillary dilator muscle and pupillary sphincter muscle.

176 pupillary reflex/pupilloplegia

pupillary reflex: Any one of a number of responses of the pupil to a stimulus, usually referring to the reaction of pupil size to varying intensities of light (see details under pupil), but also including: accommodative p.r. constriction of the pupil in near vision; consensual p.r. normal state in which dilation or constriction of one pupil in response to a stimulus is accompanied by a similar response in the pupil of the fellow eye, even if the stimulus is only delivered to one eye; its absence is an indication of a disorder of the ocular nervous system; direct p.r. reaction of pupil size to varying intensities of light in that eye only; oculosensory p.r. or oculopupillary reflex dilation of the pupils when the surface of the eyeball or eyelids is touched or irritated.

pupillary sphincter muscle: Iris muscle encircling the pupil, responsible for constricting the pupil; compare pupillary dilator muscle.

pupillary zone: Area of the iris adjacent to the pupil. pupillography: Rarely-done photography of the undilat-

ed pupil using infrared lighting; may utilize video to record light responses.

pupillometer: 1. Most commonly, another term for corneal reflection pupillometer used to measure interpupillary distance; 2. device used to measure pupil size by projecting a numeric scale onto the pupil.

pupillometry: Measuring interpupillary distance or pupillary diameter using a pupillometer.

pupilloplasty: General term for surgical procedure to alter the appearance or function of the pupil, usually referring to repair of a damaged pupil.

pupilloplegia: Paralysis of the pupil; see also fixed pupil under pupil.

Purkinje's images: Reflections from the anterior and posterior surfaces of the cornea and crystalline lens, useful in measuring strabismus as well as determining the curvature and relative position of these surfaces (eg, in ophthalmoscopy).

Purkinje's shift: Change in sensitivity of vision from daylight to dark in which the retina becomes more sensitive to the blue-green part of the electromagnetic spectrum; see also scotopia.

Q

Q-switched laser: See laser. quadrafoil: Another term for tetrafoil.

quadrantanopia, -opsia: Loss of one quarter of the visual field, resulting from some chiasmal or postchiasmal defect such that the visual fields of both eyes are affected; also called quadrant hemianopia; compare hemianopia; crossed binasal q. quadrantanopia of the lower nasal portion of one visual field and the upper nasal portion of the other visual field; crossed bitemporal q. quadrantanopia of the lower temporal portion of one visual field and the upper temporal portion of the other visual field; heteronymous q. quadrantanopia affecting different portions of the two visual fields (eg, the upper temporal region of one and the lower nasal region of the other visual field); homonymous q. quadrantanopia affecting similar portions of both visual fields (eg, the upper temporal regions of both visual fields); pie-in-the-sky q. wedge-shaped quadrantanopia in the upper quadrant and respecting the vertical; defect occurs in the temporal lobe of the optic radiations; pie-on-the-floor q. wedge-shaped quadrantanopia in the lower quadrant; defect occurs in the parietal lobe of the optic radiations.

quantum: Another term for photon.

R

radial keratotomy (RK): Refractive surgical procedure in which corneal incisions are placed radially, like the spokes of a wheel, in order to flatten the cornea and correct nearsightedness; the degree of flattening depends upon the depth (about 90% of the corneal thickness) and number (typically from four to eight) of incisions; see also keratotomy.

radiuscope: Instrument for measuring the curvature of contact lenses.

radix: General anatomic term for the “root” of a structure, as in the optic nerve r., which joins the optic nerve to the geniculate body of the brain.

range of motion: In ophthalmology, diagnostic test in which the eyes are rotated to each of the eight cardinal positions in order to evaluate the action(s) of the extraocular muscles; see also gaze.

raphe: General anatomic term for the junction line between two halves of a structure; horizontal or retinal r. horizontal line on the temporal side of the macula, dividing superior and inferior fibers of the retinal nerve fiber layer; from the raphe, the nerve fibers follow diverging paths to the optic disk.

reading vision: Another term for near vision.

recession: In ophthalmology, strabismus surgery in which a muscle is weakened by detaching then reattaching it behind its original insertion point.

recessive: In genetics, a gene whose expression is masked by a dominant gene at the same locus; if both loci contain recessive genes then they will be expressed rather than masked; see also allele; compare dominant.

180 rectus muscle/refract

rectus muscle: See inferior rectus muscle, lateral rectus muscle, medial rectus muscle, and superior rectus muscle.

recurrent corneal erosion: See corneal erosion.

red blood cell (RBC): Blood cell that contains hemoglobin and thus carries oxygen; also called erythrocyte. red-free filter: Filter that absorbs red light, rendering

blood, blood vessels, and nerve fibers more easily observed; used in ophthalmoscopy and ophthalmic photography.

red-free photography: Photography of the eye using green (“red-free”) light, so structures that appear red in white light instead appear black, thereby increasing contrast and enhancing images of blood vessels, inflammation, and hemorrhages.

red-green test: 1. Another term for duochrome test; 2. referring to color vision testing for red-green defects; 3. test to map strabismic deviations (Lancaster r-g t.).

red reflex: Reflection of light from the retina; appears as a bright red area through the pupil, due to the retina’s blood supply and pigmentation; an opacity will cast a shadow or dull the reflex’s brightness; also called retinal reflex.

reflection: Property of light such that it bounces back from the surface of an object or from an interface between two substances with different indices of refraction; light rays striking the surface or interface are called incident and those bouncing back are called reflected.

reflex: 1. Muscle reaction to stimulation; accommodative r. the triad of focusing, convergence, and miosis that occurs with near vision; oculopupillary r. dilation of the pupils when the globe or lids are irritated; pupillary r. see pupillary reflex; 2. reflection of light; see also red reflex; 3. in retinoscopy, that part of the light that reflects from the pupil; compare intercept.

refract: 1. To bend light by refraction; see refraction (definition 1); 2. to perform a refraction; see refraction (definition 2).

refraction: 1. Bending of light as it passes from one transparent media to the next such that light is bent from its normal straight-line course; see refractive index; 2. in ophthalmic practice, the act of determining what power lens is needed to correct an ametropia including the generation of a prescription for corrective lenses (which may be done only by a licensed professional); see also over-refraction; compare refractometry; 3. in ophthalmic speech and literature, the power of a lens needed to correct an ametropia is referred to as the refraction of a given individual, leading to informal descriptions such as “the (patient’s) refraction was minus 2 diopters”; see also manifest refraction.

refractive amblyopia: See amblyopia. refractive error: Another term for ametropia.

refractive index: A comparison between the speed of light traveling through air versus the speed of light as it moves through an optical medium (eg, a lens); the mathematical formula is: speed of light in air/speed of light in material = refractive index; a more dense material causes light to pass more slowly through it, and thus has a high refractive index and a higher refracting ability; denser lens materials with a high index of refraction can be fashioned into high-power lenses that are relatively thin.

refractive keratoplasty: Corneal surgery performed to correct refractive error; see also keratoplasty and refractive surgery.

refractive media: Another term for ocular media; see also medium.

refractive surgery: Surgical procedure that has the correction of an ametropia as its primary objective; see also clear lensectomy, epikeratophakia, intrastromal corneal ring, keratomileusis, keratophakia, keratoplasty, keratotomy, laser, and thermokeratoplasty.

182 refractometry/reticle

refractometry: Measuring the refractive error of a patient in order to yield information about that refractive error and without writing a prescription for corrective lenses; technical staff may legally perform refractometry but not refractions, as they do not have a license to prescribe; however, licensed personnel may use the refractometric measurement to generate a lens prescription; compare refraction (definition 2).

refractor: Instrument containing rotating lenses for the measurement of a patient’s refractive error; commonly called a phoropter, although that term actually refers to a specific brand of refractor; automated r. (AR) computerized instrument that objectively measures a patient’s refractive error (and often K readings and pupillary distance as well).

registration: In refractive surgery, process of locating diagnostic data and customized laser ablation patterns in relation to some physical or anatomic landmark on the eye so that the final treatment is centered and also rotated to the same axis in which the original diagnostic data were obtained.

regression: In refractive surgery, phenomenon in which the correction achieved in the immediate postoperative period drifts back toward the original refractive error.

regular astigmatism: See astigmatism.

relative afferent pupillary defect (RAPD): Another term for Marcus Gunn pupil.

resection: In ophthalmology usage, strabismus surgery in which a muscle is strengthened by shortening and then reattaching it to its original insertion point.

reticle or reticule: Pattern of lines or grid, usually a standardized scale, inscribed in the eyepiece of optical instruments to allow the examiner to make quantitative observations of the subject.

retina: Transparent, light-sensitive structure lining the inside of the eye; lies between the vitreous body and the choroid; light striking the retina passes through the internal limiting membrane, the retinal nerve fiber layer, the ganglion cell layer, the inner molecular and inner nuclear layers (which, like the outer molecular and outer nuclear layers just beneath them, are composed of nerve cells and synapses), the external limiting membrane, the bacillary layer (composed of the light-sensitive rod and cone cells), and finally the retinal pigment epithelium (which plays no part in visual sensation but has a key role in retinal nutrition), which is attached to the choroid; see also amacrine cells, bipolar cells, external limiting membrane, fovea, internal limiting membrane, macula, nerve fiber layer, optic disk, and ora serrata.

retinal accommodation: Accommodation triggered by the perception of an unfocused image (usually at near) on the retina.

retinal adaptation: Process whereby the retina adjusts to the level of light in the environment, becoming more or less sensitive to light under relatively dark and light conditions, respectively.

retinal apoplexy: Condition in which the central retinal vein is blocked, leading to an impairment of the retina’s blood supply and eventual damage.

retinal artery: See branch retinal artery and central retinal artery.

retinal branch vein occlusion: See branch retinal vein occlusion.

retinal central artery occlusion: See central retinal artery occlusion.

retinal central vein occlusion: See central retinal vein occlusion.