LaramyK Reference: https://opticianworks.com/glossary-of-optical-related-terms/
Accomadation:
Change in shape of the lens to focus on objects at different focal lengths.
Aphakia :
Lens of the eye has been removed (usually do to cataracts).
Ametropia:
Refractive error in the eye (could be myopia, hyperopia)
Amblyopia:
Typically begins in infancy and with one eye affected where one eye fails to achieve visual acuity even with glasses or contact lenses. Also known as “Lazy Eye”.
Amsler Grid:
Grid of horizontal and vertical lines used to detect visual defects. Usually from the retina/macula (eg macular degeneration)
Aniseikonia:
Ocular condition where there is a perceived difference in the size of images. Can be caused from anisometropia, or antimetropia.
Anisometropia:
When both eyes have unequal refractive power. Generally, of 2.00 or more diopters.
Antimetropia:
Similar to anisometropia but one eye is hyperopic while the other is myopic. Can lead to diplopia (double vision)
Asthenopia:
Eye fatigue/strain. Symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and occasional double vision
Astigmatism:
The cornea is oblong shaped (like a football), causing light rays to focus on multiple points on the retina. Corrected using a Cylinder lens.
Bench Alignment:
Setting/adjusting eyeglasses into a neutral form providing the optician a starting point to adjust the frames.
Screws are tight
Crossing (One lens has more retro/panto tilt than the other)
Co-Planar
Skewed Bridge (If bridge is not aligned then lenses will have more rotation than other lenses)
Face Form (Frame Wrap 3 Types)
Positive (Ideal or some wrap around patient’s head). Use when Frame PD is greater than Patient PD.
Negative (wraps away from patient or bridge is closer to face than lenses) Use when Patient PD is greater than Frame PD.
Neutral (no wrap, perfectly flat). Patient’s PD = Frame PD
Frame Tilt (Panto/Retro)
Temples Parallel (Flat Temple Touch Test with Frames Upside down on flat surface and temples are parallel).
Open Temple Angles (The angle of temples when the frames are open) & Closed Temple Angles
Nosepads
Cataracts:
Clouding of the Crystalline Lens.
Co-Planar Alignment:
Frames form a straight line when viewed from above, or one eye is not closer to the face than the other.
Diplopia:
Seeing “ghost images” or double vision. Seeing two separate or overlapping images of the same object when you should only be seeing one.
Distometer:
Measure vertex distance of a pair of glasses.
Emmetropic Eye (Emmetropia):
Perfect Eye, Normal Vision no refractive errors.
ESO:
Turning inward or Nasally
Exo:
Outward or temporally
Exocrine Glands:
Glands that secrete a substance onto an epithelium layer by way of a duct.
Frontal angle –
The angle of the pads when viewed from the front of the frame. The tops of the pads should be slightly closer together than the bottoms of the pad following the contours of the nose as it gets wider from top to bottom.
Hyperopia:
Far-sightedess, the eye is too short causing light rays to converge at a point behind the retina. This refractive error causes objects up close to become blurry and objects further away are clear. Corrected with plus power lenses.
Inferior:
Below something
Iseikonic Lenses:
Lenses used to correct for aniseikonia
Ishihara Test:
Test used to detect color blindness.
Jaeger Chart:
Chart used to test near visual acuity (ie reading). Text size from 0.37 mm to 2.5 mm.
Lateral:
From the sides
Low Vision Aids:
Different than normal glasses, these tools are used to correct vision where glasses cannot achieve 20/20. Patients with low-vision would have, at best, 20/70 to 20/160 with corrective glasses.
Medial:
Middle
Myopia:
Near Sightedness, the eye is longer than normal and light rays land before the retina instead of on the retina causing a refractive error. Corrected with minus power lenses, patient with myopia can see up close (near) but have trouble with objects at a distance.
Nystagmus:
Condition where the eyes make repetitive, uncontrolled movements.
Pantascopic:
Tilting top of frames/lenses away from patient (increasing vertex distance) and tilting bottom of frames/lenses toward the patient (decreasing vertex distance). A frame that is adjusted with 10 degrees of pantoscopic tilt is in the correct position. Adding pantoscopic tilt gives the perception that the lens has been LOWERED (lowers optical center). If the eyes are above the optical center you can add panto tilt.
Phoria
“Tendency” for the eye to turn away from it’s normal position.
Photophobia:
Light discomfort or sensitivity. Eyes tend to turn away from light.
Photopic:
Vision at higher light levels
Presbyopia:
Generally starting at age 40, the loss of accommodation begins as the crystalline lens looses it’s ability to focus on near objects. Corrected using reading glasses or segments with additional power (ADD POWER) on the lens.
Polarization:
Process of filtering beams of light into a singular plane. Unpolarized light is a light wave that is oscillating in more than one plane. A polarizer (polarized lenses for sunglasses) filters all but one plane.
Rectus:
The Latin word meaning “Straight”
Retroscopic:
Opposite of pantoscopic tilt where the top portion of the frames/lenses is tilting towards the patient (decreased vertex distance) and the bottom of the frames/lenses is moved away from the patients face (increased vertex distance). Increasing the retroscopic tilt gives the impression that the lenses are being RAISED (increasing height of optical center). It is generally not recommended to add retro but if the eyes are slightly below the optical center this adjustment can be made if there is no other way to adjust the OC height.
Scotoma:
A Partial alteration in the field of vision surrounded by a field of normal vision (ie blind spot)
Scotopic Vision
Vision at low light levels (Rods)
Snellen Chart:
Visual Acuity Test
Splay angle:
The angle of the pads when viewed from the top of the frame. The front edges of the pads should be closer together than the back edges.
Stereopsis:
Ability to see depth.
Superior:
Above Something, upwards, or the top.
Titmus Test:
Used to detect stereopsis.
Tropia:
“Definite” turning of the eye from it’s normal position.
Tunics of the Eye:
3 Tunics - Fibrous Tunic (scleral, cornea), Vascular Tunic (choroid, cilliary body, & iris), & Nervous Tunic (retina, macula)
Vertex Distance:
Distance between the glasses lenses and the patient’s cornea. Increasing distance will increase the perceived plus power of the lens, decreasing it will the perceived power more minus. Most doctors will refract their patients at a vertex distance of 12 mm.
Vertical angle:
The angle of the pads when viewed from the side of the frame. Since most frames will have some amount of pantoscopic tilt, the bottoms of the pads should be slightly closer to the frame front than the tops.