If you have ever been told your vision is “20/20,” but you still struggle with glare, halos, ghosting, blur, or poor night vision, you are not alone. Many vision problems are not fully explained by a standard eye chart or traditional eyeglass or contact lens prescriptions.
This Higher-Order Aberrations glossary is designed to help you understand the words and phrases you may read or hear when learning about advanced vision issues and solutions. Higher-order aberrations (HOAs) are subtle visual distortions that can affect how clearly and comfortably you see in the real world, especially at night or in challenging lighting conditions.
At the end of each definition, we’ve included a more clinical term that your doctor may have used, or that you may have seen. We put them here as a resource for you to help you better understand what you read or hear.
Some of the terms in the HOA glossary below describe what you may be experiencing, while others explain the technology and measurements used to identify and correct these problems. You do not need to memorize them. The goal is to help you feel more informed and confident as you explore whether advanced vision correction with OVITZ is right for you.
20/20 Vision
A common standard of high-quality visual acuity (defined below) is how clearly you can see letters on an eye chart at a distance. Specifically, 20/20 vision means you can see at 20 feet what an average person is expected to see at that same distance. The first “20” represents the distance from the chart, while the second is the distance a person with “normal” sight could accurately read the same line. It does not mean your vision is perfect, because it does not measure visual quality, low-light clarity, or distortion (clinical term: visual acuity).
Aberrometer
A specialized device, such as the OVITZ xwave aberrometer, that measures how light travels through your eye to detect subtle visual imperfections that glasses and standard exams often miss (clinical term: wavefront sensor).
Aberration
Any imperfection in how light is focused inside the eye that can reduce clarity or cause visual distortions (clinical term: optical aberration).
Astigmatism
A common vision condition where the eye is shaped more like a football than a basketball, causing blurred or distorted vision at all distances (clinical term: regular or irregular astigmatism).
Astigmatism is a common condition where, due to the shape of the eye’s curvature, light focuses on two points instead of just one. Astigmatism leads to blurred or distorted vision at all distances. To visualize regular astigmatism, imagine how a football curves differently along its length versus its width, compared to the even symmetry of a basketball. For irregular astigmatism, picture a rock with its uneven surface made up of various curves and angles. In these cases, light scatters to multiple focal points without any clear pattern, making it challenging or impossible to correct with standard glasses or contact lenses.
Blur
A lack of sharpness or clarity in vision that makes details appear fuzzy or smeared (clinical term: reduced image resolution).
Contrast Sensitivity
The eye’s ability to see an object clearly against its background, like spotting a white car in a thick fog or reading gray text on a gray page.
Contact Lenses
Thin, curved discs of biomedical plastic are worn directly on the eye to provide clear vision without glasses. They are generally categorized as “soft” or “hard” based on their material, flexibility, and how they rest on the eye’s surface.
Cornea
The clear, dome-shaped front surface of the eye that helps focus incoming light (clinical term: anterior ocular surface).
Corneal Scarring
Permanent changes or damage to the cornea that can scatter light and reduce visual clarity, often after injury, infection, certain diseases, or surgery (clinical term: corneal opacity).
Corneal Crosslinking
A medical procedure that strengthens the cornea to slow or stop conditions like keratoconus from thinning and worsening (clinical term: corneal collagen crosslinking).
Double Vision
Seeing two images instead of one, either side by side or overlapping. Monocular double vision occurs when one eye sees a doubling of images, often caused by optical distortions within the eye. Binocular double vision occurs when the eyes do not work together and are unable to fuse a single image, usually due to neurological, vascular, or muscle issues. (clinical term: diplopia).
Flare
Streaks or rays of light that appear around bright objects, especially noticeable at night (clinical term: light scatter).
Glasses (clinical term: Spectacles)
Eyewear designed to correct basic focusing problems like nearsightedness, farsightedness, and astigmatism (clinical term: spherocylindrical correction).
Ghosting
A faint second image or shadow that appears next to objects, making text or lights look duplicated (clinical term: image doubling).
Glare
Excessive brightness that makes it hard to see clearly, often from headlights, screens, or sunlight (clinical term: light streaking).
Halos
Bright rings or circles that appear around lights, especially at night (clinical term: optical diffraction effects).
Higher-Order Aberrations (clinical term: HOAs)
Complex optical imperfections in the eye’s visual system that glasses, contacts, and standard eye exams cannot correct, often causing glare, halos, ghosting, and poor night vision (clinical term: higher-order wavefront errors).
Hyperopia (clinical term: Farsightedness)
A focusing condition where nearby objects appear blurry because light focuses behind the retina (clinical term: positive refractive error).
INTACS®
Small, surgically implanted plastic segments that help reshape the cornea in some keratoconus patients (clinical term: intracorneal ring segments).
Keratoconus
A progressive condition where the cornea becomes thinner and cone-shaped, leading to distorted and fluctuating vision (clinical term: corneal ectasia).
LASIK
A common laser eye surgery that reshapes the cornea by creating a flap and reshaping the tissue beneath to correct basic vision prescriptions, but can sometimes induce higher-order aberrations (clinical term: laser refractive surgery, and laser-assisted in situ keratomileusis).
Lower-Order Aberrations
Common vision issues like nearsightedness, farsightedness, and astigmatism that are easily corrected with glasses or contacts (clinical term: defocus, sphere and astigmatism).
Myopia (Nearsightedness)
A common eye condition where distant objects appear blurry because light focuses in front of the retina instead of on the retina (clinical term: negative refractive error).
OVITZ
A vision technology company redefining visual clarity through the correction of higher-order aberrations. Their groundbreaking closed-loop, wavefront-guided production system is the first of its kind, making advanced wavefront technology more accessible to doctors and patients alike.
OVITZ-Added Lenses
Specialty lenses customized using OVITZ measurements to improve visual clarity beyond what standard lenses can provide (clinical term: wavefront-guided optics).
OVITZ-Authorized Doctor
An eye doctor trained and equipped to use OVITZ technology and provide OVITZ-Added Lenses (clinical term: certified provider of OVITZ HOA optics).
OVITZ HOA Optic
A customized optical design created to reduce higher-order aberrations specific to your eyes (clinical term: custom wavefront correction).
OVITZ HOA Optics
The collection of personalized optical corrections used in OVITZ-Added Lenses to improve image quality (clinical term: high-order optical corrections).
OVITZ Technology
The combination of advanced measurement tools, software, and lens design used to analyze and correct visual distortions (clinical term: wavefront-guided system).
OVITZ xwave
The OVITZ measurement platform captures detailed data about how light travels through your eye (clinical term: advanced wavefront aberrometry).
Point of Light Test
A simple visual test where patients look at a small light to reveal distortions like starbursts, flares, or ghosting (clinical term: point spread visualization).
Post-LASIK HOAs
Higher-order aberrations that develop after LASIK surgery and may cause persistent visual symptoms despite good eye chart results (clinical term: surgically induced aberrations).
PRK (Photorefractive keratectomy)
A common laser eye surgery that reshapes the cornea, without creating a flap, to correct basic vision prescriptions, but can sometimes induce higher-order aberrations (clinical term: laser refractive surgery).
Radial Keratotomy (RK)
An older vision correction surgery that used small corneal incisions and often leads to long-term visual distortions (clinical term: incisional refractive surgery).
Rigid Gas Permeable Lens
A firm, durable contact lens of various designs that maintains its shape on the eye to provide sharp vision. (clinical term: RGP lenses).
Sclera
The white outer wall of the eye that provides structure and support (clinical term: prosthetic shell).
Scleral Lens
A large specialty contact lens that rests on the sclera and vaults over the cornea, often used for complex vision correction (clinical term: large-diameter rigid lens).
Soft Contact Lens
A flexible style contact lens that conforms to the shape of the eye for immediate comfort and clear vision.
Starburst
A pattern where lights appear to radiate outward in spikes, especially noticeable at night (clinical term: radial light scatter).
Unhappy 20/20
A term for patients who technically see 20/20 on an eye chart but still struggle with poor visual quality, glare, or night vision (clinical term: functional vision complaint).
Visual Acuity
A measure of how well you can identify letters or symbols at a standardized distance, but not a full measure of visual quality (clinical term: resolution testing).