Question | Answer |
accommodation | Adjustment of the eye for seeing objects at various distances, accomplished by aletring the shape of the crystalline lens by action of ciliary muscle, thus changeing its power and focusing a clear image on the retina |
After Image | Visual impression which remains after a stimulus is removed |
AMBLYOPIA EX ANOPSIA | Amblyopia aquired through lack of use of the eye |
AQUEOUS | Clear fluid which fills the front part of the eye. |
ASTHNEOPIA | Eye strain caused by fatigue of the internal external muscle |
ASTIGMATISM | Defective curvature of the refractive surfact of the eye as a result which light rays are not sharply focused on the retina for either near or distance vision |
BINOCULAR VISION | The ability to use the two eye simultaneously to focus on the same object and to fuse the two images into a single image, which gives a correct interpretation to its solidity and its positon in space |
CATARACT | A condition in whiich the crystalline lens of the eye becomes opaque with consequent loss of visual acuity |
CHIASMA | The crossing of the nerve fibers of the optic nerve |
CONES AND RODS | The two types of light-sensetive receptors that are present in the retina and make it possible for it to transmit visual impulses to the brain. Cones are sensetive to fine detail and color; rods are concern with motion and vision at low degrees of illumin |
CONVERGENCE | The process of directing the visual axes of the two eyes to a near point, with the result that the pupils of the two eyes are closer together, or turned iward |
CONVERGENCE: NEAR POINT | The nearest point at which the two eyes can direct their gaze simultaneously; normally about three inches from the nose |
CORNEAL GRAFT | operation to restore vision by replacing a section of the opaque cornea with transparent cornea |
CYCLOPLEGICS | A group of drugs, instilled into the eye, which cause temporary paralysis and relaxation of the ciliary muscles that control accommodation and dilation of the pupil; often used to ascertain the error of refraction. |
DIOPTER (AB. D) | Unit of measurementof strength or refractive power 3r of lensus |
DIPLOPIA | Double vision; i.e. perception of two images of a single object. |
DIVERGENCE | Simultaneous turning outward of the eyes away from each other |
DYSLEXIA | In ability to read or understand printed symbols; may be cause by many factors |
EMMETROPIA | Refractive condition of the normal eye, at rest, which brings the image of distant objects to focus on the retina |
ENUCLEATION | Complete surgical removal of the eyeball |
ESOPHORIA | Latent tendency of the eye to turn inward (see Heterophoria) |
ESOTROPIA | An observaable turning in of one eye (convergent strambismus or crossed eye) |
EXOPHORIA | Latent tendency of the eye to turn outward (see heterophoria) |
EXOPHTHALMUS | Abnormal protrusion or bulging of the eye from their sockets |
EXTORTION | Out ward rotation |
EXOTROPIA | Observable turning of one eye (or both) from the visual axis of the outer |
FIELD OF VISION | The entire area seen at one time by the fixed eye; i.e. withouting shifting the head or eye |
FLUCTUATING LENS MYOPIA | Swelling of lens fiber caused by diabetes |
Glaucoma | A dosease of the eye marked by a mechanical increase in the intraocular pressure. This causes organic changes in the optic nerve and defects in the visual field |
Heterophoria | Tendency of the eyes to diviate from the normal position for binocular fixation, counter balance by simultaneous fixation and fusion "prompted by the desire for singular binocular vision." Diviation is not usually apparent, in which case it is called late |
HETEROTROPIA | Squint, strabismus, cross-eye; when one or more muscles are out of balance, one eye may turn in while the other fixes. I may be a divergent or vertical muscle |
Hydrophthalmus (Congenital glaucoma) | A rear congenital defect in which the eye ball is abnormally large as a result of pressure elevation. It is present at birth or develop early in infancy. |
HYPEROPIA | Hypermetropia, farsightedness; condition of the eye in which light rays from the distance of objects are brought to focus behind the retina when the eye is at rest. |
IRIDECTOMY | Surgery in which a piece of the Iris is removed |
IRITIS | Inflamation of the Iris; condition marked by pain,inflamation, and discomfort from the eye. |
LACRIMATON | Production of tears |
LAGOPHTHALMOS | Inadequate closure of the eyelids |
MYPOIA | A ractive error in which rays of light come to focus in front of the retina, as a result of the eye ball being too long from front to back, or having excessive curvature of cornea or lens |
MYOPIC | Near sigtedness; a conditin of the eye in which the point of focus for rays of light from distant objects is infornt of the retina |
NYSTAGMUS | An involuntary movement of the eyeballs rapidly from side to side, up and down, in a rotary motion, or mixed. |
OCCLUSION | Act of obsecuring the vision of one eye, so as to focus the use of the other eye |
OPTIC ATROPHY | Wasting away of the optic nerve fiber characterized by pallor of the optic nerve head and accompanying visual loss. |
PERIPHERAL VISION | Ability to perceive presence, motion, or color of objects outside of the direct line of vision. |
PHORIA | A latent tendency toward crossed eye; condition not usually observed |
PRESBYOPIA | Decreased elasticity in the lens of the eyeball causing some loss of accommodatin; usually seen in older persons. |
PTOSIS | A drooping of the upper lid. Due to weakness or paralysis of a portion of the third nerve, which control the levator muscle that raises the lid. |
REFRACTIVE ERROR | A defect in the eyes ability's to bring light rays to focus on the retin. |
RETINAL DETACHMENT | Seperation of the retina from the underline vascular or choroid layer of the eye which brakes cnnectins between the rods and cones and the pigment layer; most often the result of a hole or tear in the retina. |
RETINITIS PIGMENTOSA | A form of hereditary degeneration of the retina which begins as night blindness, but which produces a gradua loss of vision that may become complete. |
RETROLENTAL FIBROPLASIA | An opaque membrane seen behind the lens, often found in babies born prematurely who have had an excess of oxygen. |
SCOPOTIC VISION | Seeing with the rods of the eyes at dust |
SCOTOMA | Abnormal blind spot in the field of vision, surrounded by an area of normal vision |
SECOND SIGHT | Increase in Mypoia due to early stages of Cattaract |
STEREOPSIS | Depth perception |
STRABISMUS | Manifest diviation of the eyes so that they are not simultaneously directed to the same object |
SYMPATHATIC OPHTHALMITIS | Severe inflamatin of one eye due to infection in the other eye |
VISUAL AQUITY | Sharpness of vision, the abilit of the eye to distinguish detail. |