Vision Screening Resources and Glossary
The Clinic Checklist (PDF) is available for download.
The Quick Reference Guide (PDF) is available for download.
- American Academy of Ophthalmology
- Minnesota Academy of Ophthalmology
- American Association for Pediatric Ophthalmology & Strabismus
- American Optometric Association
- American Academy of Pediatrics
- American Academy of Family Physicians
- National Center for Children's Vision and Eye Health
- National Eye Institute
- Sight & Hearing Association
Accommodation - the adjustment of the lens to focus at different distances through action of the ciliary muscle
Amblyopia - poor vision in one or both eyes not due to organic defect
Anisometropia - inequality in the refractive power of the two eyes of considerable degree
Anterior chamber - the space between the cornea and the iris
Aqueous humor - the clear fluid which fills the anterior and posterior chambers of the eye
Astigmatism - a refractive error in which a defect of curvature on one of the refractive surfaces of the eye prevents a clear image from being focused on the retina
Binocular vision - the ability to use both eyes simultaneously to focus on the same object and fuse the two images into one with the correct interpretation of solidity and position in space
Blepharitis - inflammation of the glands and lash follicles along the margin of the eyelids
Blindness - legal blindness is a visual acuity of 20/200 and or the ability to see only 20% or less of the visual field after best correction in the better eye
Blind spot - area where retinal nerve fibers converge (optic disc) to form the optic nerve. Corresponds to the area of non-vision in the visual field
Cataract - a defect in the transparency or opacity of the lens or its capsule
Chalazion - a lump on the eyelid that results from chronic inflammation of meibomian gland
Choroid - the vascular layer located between the sclera and the retina
Cilia - of the eye refers to eyelashes
Ciliary body - the portion of the uveal tract between the iris and the choroid that contains the muscles of accommodation and secretes aqueous
Coloboma - absence or defect of some ocular tissue, usually a congenital fissure of any part of the eye, such as an incomplete iris
Color deficiency - inability to perceive differences in color, usually for red-green, rarely for blue-yellow. It can range from mild to severe in degree. It is more common in males than females
Concave lens - a lens having the power to diverge parallel rays of light. It is used to correct myopia
Cones - one of two types of light-sensitive cells on the retina. Cones are more numerous in the area of the macula and are responsible for seeing color and fine detail
Conjunctiva - delicate membrane that lines the eyelids and the exposed part of the sclera
Conjunctivitis - inflammation of the conjunctiva
Convergence - simultaneous turning of the eyes toward each other
Convex lens - a lens having the power to converge parallel light rays to bring an image to focus. It is used to correct hyperopia or presbyopia
Cornea - the clear transparent membrane that covers the iris and pupil and joins the conjunctiva
Crystalline lens - a transparent colorless body suspended in the anterior portion of the eyeball between the aqueous and vitreous chambers. Its function is to help bring light rays into focus.
Dacryocystitis - inflammation of the tear sac, usually due to blockage
Depth perception - the ability to perceive the solidity of objects and their relative position in space. Stereopsis
Diopter - unit of measurement expressing the strength or refractive power of a lens at one meter
Diplopia - double vision
Divergence - simultaneous turning of the eyes away from each other
Emmetropia - absence of refractive error
Epicanthus - congenital skin fold overlying the inner portion of the upper lid and the inner canthus; simulates the appearance of esotropia. Tends to recede as the bridge of the nose narrows in early childhood
Esophoria - a latent tendency of the eye to turn inward
Esotropia - a manifest inward deviation of the eye
Exophoria - a latent tendency of the eye to turn outward
Exotropia - a manifest outward deviation of the eye
Farsightedness - a lay term for hyperopia
Field of Vision - the entire area which can be seen at one time without shifting the head or eyes
Floaters - opacities within the vitreous space that cast moving shadows on the retina
Focus - adjustment of the lens to produce a clear picture
Fovea - small depression in the retina at the back of the eye; part of the macula adapted for the most acute vision
Fusion - the integration of two separate images into a single mental picture
Glaucoma - a disease marked by increased intra-ocular pressure, which can cause blindness if not treated
Hyperopia - the refractive condition of the eye at rest such that light rays from a distant object are focused behind the retina
Hypertropia - a tendency of one eye to deviate upward
Iris - the colored circular membrane surrounding the pupil
Iritis - inflammation of the iris
Lacrimal apparatus - the system responsible for the formation, secretion, and drainage of tears
Lazy eye - lay term for amblyopia
Lens - the transparent body, convex on both surfaces, lying directly behind the iris and serves to focus light rays on the retina
Lids - the outermost covering of the eye
Macula - a small depressed area in the retina where sharpest vision occurs
Monocular - pertaining to or having one eye
Myopia - a refractive error in which the eyeball is too long from front to back or the refractive power so strong so that parallel rays of light are focused in front of the retina
Near point of accommodation - the nearest point at which the eye can see an object distinctly. It varies according to the power of accommodation in the individual
Near point of convergence - the nearest point at which two eyes can direct their gaze simultaneously, normally about three inches from the nose
Nearsighted - lay term for myopia
Night blindness - a condition in which the sight is good by day, but deficient at night or in faint light
Nystagmus - an involuntary rapid movement of the eyeball; it may be lateral, vertical, rotary or mixed
Occluder - a device used to cover one eye during vision screening
Oculus dexter (O.D.) - right eye
Oculus sinister (O.S.) - left eye
Oculi uterque (O.U.) - both eyes
Ophthalmologist - an MD who specializes in medical and surgical diagnosis and treatment of defects and diseases of the eye, prescribes drugs, eyeglasses, contact lenses and optical aids
Ophthalmoscope - an instrument used in examining the interior of the eye
Optic nerve - nerve by which visual impulses are transmitted from the retina to the brain
Optician - a person who grinds lenses, fits them into frames, and adjusts the frames to the wearer
Optometrist (OD) - a doctor of optometry who specializes in the diagnosis and treatment of functional vision problems, prescribes correctives lenses, contact lenses, or visual therapy and examines for eye disease or ocular signs of systemic disease
Orthophoria - straight eyes
Peripheral vision - ability to perceive presence, motion or color of objects to the side
Phoria - a root word denoting a latent tendency of one eye to deviate up, down, left or right
Photophobia - eyes having an abnormal sensitivity or discomfort in light
Plus lens - a convex lens used for screening farsightedness by checking the eyes’ ability to accommodate at distance
Posterior chamber - space between the posterior surface of the iris and anterior surface of the lens filled with aqueous fluid
Presbyopia - physiological change in the eye characterized by the lens becoming less elastic and therefore not able to focus up close
Ptosis - drooping of the upper eyelid
Pupil - the opening at the center of the iris that adjusts to allow light to enter the eye
Refraction - determination of refractive errors of the eye and correction by glasses
Retina - the innermost light sensitive layer of the eye; contains the rods and cones
Rods - vision cells that are not color sensitive; used for perception of motion, in low illumination, and in night vision
Sclera - the white part of the eye, which with the cornea, forms the external protective coat of the eye
Stereopsis - binocular depth perception
Strabismus - eyes that are out of alignment
Sty - infection of a gland in the margin of the eyelid
Suppression - a condition in which the image from one eye is ignored (suppressed) by the brain. Suppression that exists for a period of time could lead to amblyopia
Tropia - a root word denoting a manifest turning in, out, up or down of one eye in relation the other
Uvea - vascular and pigmented layer of the eye, includes the choroid, ciliary body and the iris
Visual acuity - the ability of the eye to distinguish detail as an object is placed farther away or as it becomes smaller in size
Vitreous humor - transparent gelatinous substance that fills the space behind the lens and keeps the eyeball expanded and in shape
Unless otherwise indicated the following professional recommendations and guidelines were used to inform the general revision of this manual:
- Roch-Levecq, A.C., Brody, B.L., Thomas, R.G., Brown, S.I. (2008). Ametropia, preschoolers’ cognitive abilities and effects of spectacle correction. Arch Ophthalmology, 126 (2) 181-187
- AAP, (2003). Eye examination in Infants, Children, and Young Adults by Pediatricians. Pediatrics, 111(4) 902-907.
- Cotter, S. A., Cyert, L.A., Miller, J.M., Quinn, G.E., for the National Expert Panel to the National center for Children’s Vision and Eye Health, (2015). Vision Screening for Children 36 to 72 Months: Recommended Practices, Optometry and Vision Science 92, (1), 6-16.
- USPTF, U. S., (2011). Vision Screening for Children 1 to 5 Years of Age: US Preventative Services Task Force Recommendation Statement. Pediatrics, 341-346.
- Vision in Preschoolers Study Group, (2005). Sensitivity of Screening Tests for detecting Vision In preschoolers - targeted Vision Disorders. Optometry and Vision Science, 88(5), 432-435.
- Canadian Paediatric Society, (2009). Vision screening in infants, children and youth .Paediatric and Child Health. 2009 Apr; 14(4): 246-248. Retrieved 2015
Plus Lens Reference
- Williams WR, Latif AH, Hannington L, Watkins DR. Hyperopia and educational attainment in a primary school cohort. Archives of Disease in Childhood. 2005: 90(2):150-153 Retrieved 2015 from the National Center for Biotechnology Information
Instrument-Based Vision Screening References
- American Academy of Pediatrics, (2012). Instrument Based Pediatric Vision Screening Policy Statement. Pediatrics, 983-986.
- Neely, D. & Bradford, G. (2015). Pediatric Vision Screening: Guidelines for Primary Care Providers and School Nurses ( Power Point slides), retrieved from the American Association for Pediatric Ophthalmology and Strabismus
- American Association of Pediatric Ophthalmology and Strabismus, (2014, June 18). AAPOS Techniques for pediatric vision screening.
- Matta NS, Singman EL, Silbert DI. Performance of the Plusoptix S04 photoscreener for the detection of amblyopia risk factors in children aged 3 to 5. J AAPOS. 2010:147-9.
- Arnold RW, Arnold AW, Armitage MD, Shen JM, Hepler TE, Woodard TL. Pediatric photoscreeners in high risk patients 2012: a comparison study of Plusoptix, IScreen, and SPOT. Binocul Vis Strabolog Q Simms Romano. 2013:20-8.
- Singman E, Matta N, Tian J, Brubaker A, Silbert D. A comparison of the Plusoptix S04 and A09 photoscreeners. Strabismus. 2013:85-7.
- Bloomberg JD, Suh DW. The accuracy of the Plusoptix A08 photoscreener in detecting risk factors for amblyopia in central Iowa. J AAPOS. 2013: 301-4.
- Garry G, Donahue SP. In press. J AAPOS. 2014
- Donahue SP, Baker JD, Scott WE, Rychwalski P, Neely DE, Tong P, Bergsma D, Lenahan D, Rush D, Heinlein K, Walkenbach R, Johnson TM. Lions Clubs International Foundation Core Four Photoscreening: results from 17 programs and 400,000 preschool children. J AAPOS. 2006:44-8.
- Rowatt AJ, Donahue SP, Crosby C, Hudson AC, Simon S, Emmons K. Field evaluation of the Welch Allyn SureSight vision screener: incorporating the vision in preschoolers study recommendations. J AAPOS. 2007:243-8.
- Longmuir SQ, Pfeifer W, Leon A, Olson RJ, Short L, Scott WE. Nine-year results of a volunteer lay network photoscreening program of 147,809 children using a photoscreener in Iowa. Ophthalmology. 2010:1869-75.
- Longmuir Sq, Boese EA, Pfeifer W, Zimmerman B, Short L, Scott WE. Practical community photoscreening in very young children. Pediatrics. 2013:764-9.
- Ransbarger KM, Dunbar JA, Choi SE, Khazaeni LM. Results of a community vision-screening program using the SPOT photoscreener. J AAPOS. 2013:516-20.
- Silbert DI, Matta NS, Ely AL. Comparison of SureSight autorefractor and Plusoptix A09 photoscreener for vision screening in rural Honduras. J AAPOS. 2014:42-4.
- Donahue SP, Arthur B, Neeley DE, Arnold RW, Silbert D, Ruben JB, POS Vision Screening Committee. Guidelines for automated preschool vision screening: a 10-year, evidence-based update. J AAPOS. 2013:4-8.
- Bloomberg JD and Suh DW. The accuracy of the Plusoptix A08 photoscreener in detecting risk factors for amblyopia in central Iowa. JAAPOS. 2013(3):301-4.
- Nottingham Chaplin PK, Baldonado K, Hutchinson A, Moore B. Vision and Eye Health: Moving into the digital age with instrument-based vision screening. NASN School Nurse, 2015;30(3):154-160