Ocular dominance
Encyclopedia
Ocular dominance, sometimes called eye dominance or eyedness, is the tendency to prefer visual
input from one eye
to the other. It is somewhat analogous to the laterality
of right or left handedness
; however, the side of the dominant eye and the dominant hand do not always match. This is because both hemispheres control both eyes, but each one takes charge of a different half of the field of vision, and therefore a different half of both retinas. There is thus no direct analogy between "handedness" and "eyedness" as lateral
phenomena.
Approximately two thirds of the population is right-eye dominant and one third left-eye dominant; however in a small portion of the population neither eye is dominant. Dominance does appear to change depending upon direction of gaze due to image size changes on the retina
s. There also appears to be a higher prevalence of left-eye dominance in those with Williams–Beuren syndrome, and possibly in migraine
sufferers as well. Eye dominance has been categorized as "weak" or "strong"; highly profound cases are sometimes caused by amblyopia
or strabismus
.
In those with anisometropic
myopia
(i.e. different amounts of nearsightedness between the two eyes), the dominant eye has been found to be the one with more myopia.
In normal binocular vision
there is an effect of parallax
, and therefore the dominant eye is the one that is primarily relied on for precise positional information. This may be especially important in sports which require aim, such as archery
, darts
or shooting sports
.
It has been asserted that cross-dominance
(in which the dominant eye is on one side and the dominant hand is on the other) is advantageous in sports requiring side-on stances (e.g. baseball
, cricket
, golf
); however, recent studies have shown this not to be the case. In a study of professional baseball players, hand-ocular dominance patterns did not show an effect on batting average
or ERA
. Similarly, a recent South African study found that "cricketer
s were not more likely to have crossed dominance" than the normal population.
Ocular dominance is an important consideration in predicting patient satisfaction with monovision correction in cataract surgery
, refractive surgery
, and contact lens
wear.
Forced choice tests of dominance, such as the Dolman method, allow only a right or left eye result.
The eye patch does not need to be black to blot out all light, and the dominant eye does not need to stay closed. The eye patch simply presents the dominant eye with a static unchanging visual field containing nothing of visual importance, and the brain is forced to rely on the suppressed eye for visual information.
The experience does cause irritation and frustration for the eye patch wearer since their visual capabilities for comprehension will be reduced until the brain starts to adapt to not being able to use the dominant eye.
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
input from one eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
to the other. It is somewhat analogous to the laterality
Laterality
Laterality is the preference that most humans show for one side of their body over the other. Examples include right-handedness or left-footedness. It may also apply to other animals, or to plants.- Human laterality :...
of right or left handedness
Handedness
Handedness is a human attribute defined by unequal distribution of fine motor skills between the left and right hands. An individual who is more dexterous with the right hand is called right-handed and one who is more skilled with the left is said to be left-handed...
; however, the side of the dominant eye and the dominant hand do not always match. This is because both hemispheres control both eyes, but each one takes charge of a different half of the field of vision, and therefore a different half of both retinas. There is thus no direct analogy between "handedness" and "eyedness" as lateral
Laterality
Laterality is the preference that most humans show for one side of their body over the other. Examples include right-handedness or left-footedness. It may also apply to other animals, or to plants.- Human laterality :...
phenomena.
Approximately two thirds of the population is right-eye dominant and one third left-eye dominant; however in a small portion of the population neither eye is dominant. Dominance does appear to change depending upon direction of gaze due to image size changes on the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
s. There also appears to be a higher prevalence of left-eye dominance in those with Williams–Beuren syndrome, and possibly in migraine
Migraine
Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
sufferers as well. Eye dominance has been categorized as "weak" or "strong"; highly profound cases are sometimes caused by amblyopia
Amblyopia
Amblyopia, also known as lazy eye, is a disorder of the visual system that is characterized by a vision deficiency in an eye that is otherwise physically normal, or out of proportion to associated structural abnormalities of the eye...
or strabismus
Strabismus
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...
.
In those with anisometropic
Anisometropia
Anisometropia is the condition in which the two eyes have unequal refractive power; that is, are in different states of myopia , hyperopia or in the extreme, antimetropia , the unequal refractive states cause unequal rotations thus leading to diplopia and asthenopia.Anisometropia can adversely...
myopia
Myopia
Myopia , "shortsightedness" ) is a refractive defect of the eye in which collimated light produces image focus in front of the retina under conditions of accommodation. In simpler terms, myopia is a condition of the eye where the light that comes in does not directly focus on the retina but in...
(i.e. different amounts of nearsightedness between the two eyes), the dominant eye has been found to be the one with more myopia.
Importance of ocular dominance
Since 'worse eye dominance' goes against nature and common sense (i.e., in 'handedness', the stronger/faster/better hand is dominant, enabling quicker and more accurate actions, reactions, and decision-making) studies should be done to determine whether the myopes in question (virtually all of them?) undergo a reversal of their normal better eye dominance as a result of continuously wearing their prescribed lenses, and if so then investigations are needed into whether opticians are incorrectly prescribing lenses which bring both eyes to equal eyesight (rather than leaving the worse eye slightly undercorrected) and thus inducing the abnormal reversal and contributing to continued worsening eyesight.In normal binocular vision
Binocular vision
Binocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bini for double, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a...
there is an effect of parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
, and therefore the dominant eye is the one that is primarily relied on for precise positional information. This may be especially important in sports which require aim, such as archery
Archery
Archery is the art, practice, or skill of propelling arrows with the use of a bow, from Latin arcus. Archery has historically been used for hunting and combat; in modern times, however, its main use is that of a recreational activity...
, darts
Darts
Darts is a form of throwing game where darts are thrown at a circular target fixed to a wall. Though various boards and games have been used in the past, the term "darts" usually now refers to a standardised game involving a specific board design and set of rules...
or shooting sports
Shooting sports
A shooting sport is a competitive sport involving tests of proficiency using various types of guns such as firearms and airguns . Hunting is also a shooting sport, and indeed shooting live pigeons was an Olympic event...
.
It has been asserted that cross-dominance
Cross-dominance
Cross-dominance, also known as mixed-handedness, mixed dominance, or hand-confusion, is a motor skill manifestation where a person favors one hand for some tasks and the other hand for others. For example, a cross-dominant person might write with the left hand but throw primarily with the right...
(in which the dominant eye is on one side and the dominant hand is on the other) is advantageous in sports requiring side-on stances (e.g. baseball
Baseball
Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...
, cricket
Cricket
Cricket is a bat-and-ball game played between two teams of 11 players on an oval-shaped field, at the centre of which is a rectangular 22-yard long pitch. One team bats, trying to score as many runs as possible while the other team bowls and fields, trying to dismiss the batsmen and thus limit the...
, golf
Golf
Golf is a precision club and ball sport, in which competing players use many types of clubs to hit balls into a series of holes on a golf course using the fewest number of strokes....
); however, recent studies have shown this not to be the case. In a study of professional baseball players, hand-ocular dominance patterns did not show an effect on batting average
Batting average
Batting average is a statistic in both cricket and baseball that measures the performance of cricket batsmen and baseball hitters. The two statistics are related in that baseball averages are directly descended from the concept of cricket averages.- Cricket :...
or ERA
Earned run average
In baseball statistics, earned run average is the mean of earned runs given up by a pitcher per nine innings pitched. It is determined by dividing the number of earned runs allowed by the number of innings pitched and multiplying by nine...
. Similarly, a recent South African study found that "cricketer
Cricketer
A cricketer is a person who plays the sport of cricket. Official and long-established cricket publications prefer the traditional word "cricketer" over the rarely used term "cricket player"....
s were not more likely to have crossed dominance" than the normal population.
Ocular dominance is an important consideration in predicting patient satisfaction with monovision correction in cataract surgery
Cataract surgery
Cataract surgery is the removal of the natural lens of the eye that has developed an opacification, which is referred to as a cataract. Metabolic changes of the crystalline lens fibers over time lead to the development of the cataract and loss of transparency, causing impairment or loss of vision...
, refractive surgery
Refractive surgery
Refractive eye surgery is any eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea or cataract surgery. The most common methods today use excimer lasers to...
, and contact lens
Contact lens
A contact lens, or simply contact, is a lens placed on the eye. They are considered medical devices and can be worn to correct vision, for cosmetic or therapeutic reasons. In 2004, it was estimated that 125 million people use contact lenses worldwide, including 28 to 38 million in the United...
wear.
Determination of ocular dominance
A person's dominant eye "is determined by subjective alignment of two objects presented at a stereodisparity far beyond Panum's area". There are a number of ways to do this:- The Miles test. The observer extends both arms, brings both hands together to create a small opening, then with both eyes open views a distant object through the opening. The observer then alternates closing the eyes or slowly draws opening back to the head to determine which eye is viewing the object (i.e. the dominant eye)http://www.archeryweb.com/archery/eyedom.htm.
- The Porta test. The observer extends one arm, then with both eyes open aligns the thumb or index finger with a distant object. The observer then alternates closing the eyes or slowly draws the thumb/finger back to the head to determine which eye is viewing the object (i.e. the dominant eye) http://www.golf-spec.com/EyeDominantPage.htm http://web.archive.org/web/20080215220943/http://www.sportvue.com/support/dominance.php.
- The Dolman method also known as the hole-in-the-card test. The subject is given a card with a small hole in the middle, instructed to hold it with both hands, then instructed to view a distant object through the hole with both eyes open. The observer then alternates closing the eyes or slowly draws the opening back to the head to determine which eye is viewing the object (i.e. the dominant eye).
- The convergence near-point test. The subject fixates an object that is moved toward the nose until divergenceDivergence (eye)In ophthalmology, divergence is the simultaneous outward movement of both eyes away from each other, usually in an effort to maintain single binocular vision when viewing an object. It is a type of vergence eye movement.-References:...
of one eye occurs (i.e. the non-dominant eye). It is an objective test of ocular dominance. - Certain stereogramStereogramA stereogram is pair of two-dimensional panels depicting the view of a scene or an object from the vantage points of the right and left eyes. Observing the panels superimposed in a stereoscope results in the experience of three-dimensionality by virtue of the fact that object depth is encoded as...
s http://web.archive.org/web/20080522171306/http://www.math.gatech.edu/~berglund/eyedominance.html. - The Pinhole test.
- The Ring test.
- Lens Fogging Technique. The subject fixates a distant object with both eyes open and appropriate correction in place. A +2.00 or +2.50 lens is alternately introduced in front of each eye, which blurs the distant object. The subject is then asked to state in which eye is the blur more noticeable. This is the dominant eye.
- The Camera Test. The subject brings a camera up to his/her face. Whichever eye is used to look through the viewfinder is the dominant eye. This particular test is more indicative than it is certain; it is similar to unexpectedly throwing a ball at someone to see which hand they catch it with, which usually turns out to be the dominant hand.
Forced choice tests of dominance, such as the Dolman method, allow only a right or left eye result.
Treatment
It is possible to change eye dominance by actively suppressing the visual field of the dominant eye. This is achieved with an eye patch bandage that covers the dominant eye, with adhesive tape around the patch perimeter.The eye patch does not need to be black to blot out all light, and the dominant eye does not need to stay closed. The eye patch simply presents the dominant eye with a static unchanging visual field containing nothing of visual importance, and the brain is forced to rely on the suppressed eye for visual information.
The experience does cause irritation and frustration for the eye patch wearer since their visual capabilities for comprehension will be reduced until the brain starts to adapt to not being able to use the dominant eye.