WordNet

to take an action to protect against future problems; "Count the cash in the drawer twice just to cover yourself"
clothe, as if for protection from the elements; "cover your head!" (同)wrap up
a recording of a song that was first recorded or made popular by somebody else; "they made a cover of a Beatles song" (同)cover version, cover song
fire that makes it difficult for the enemy to fire on your own individuals or formations; "artillery provided covering fire for the withdrawal" (同)covering fire
the act of concealing the existence of something by obstructing the view of it; "the cover concealed their guns from enemy aircraft" (同)covering, screening, masking
a false identity and background (especially one created for an undercover agent); "her new name and passport are cover for her next assignment"
make up for shortcomings or a feeling of inferiority by exaggerating good qualities; "he is compensating for being a bad father" (同)compensate, overcompensate
span an interval of distance, space or time; "The war extended over five years"; "The period covered the turn of the century"; "My land extends over the hills on the horizon"; "This farm covers some 200 acres"; "The Archipelago continues for another 500 miles" (同)continue, extend
hide from view or knowledge; "The President covered the fact that he bugged the offices in the White House" (同)cover up
protect by insurance; "The insurance wont cover this" (同)insure, underwrite
form a cover over; "The grass covered the grave" (同)spread over
act on verbally or in some form of artistic expression; "This book deals with incest"; "The course covered all of Western Civilization"; "The new book treats the history of China" (同)treat, handle, plow, deal, address
be responsible for guarding an opponent in a game
be sufficient to meet, defray, or offset the charge or cost of; "Is this enough to cover the check?"
help out by taking someones place and temporarily assuming his responsibilities; "She is covering for our secretary who is ill this week"
hold within range of an aimed firearm
invest with a large or excessive amount of something; "She covered herself with glory"
maintain a check on; especially by patrolling; "The second officer covered the top floor"
play a higher card than the one previously played; "Smith covered again"
protect or defend (a position in a game); "he covered left field"
provide for; "The grant doesnt cover my salary"
provide with a covering or cause to be covered; "cover her face with a handkerchief"; "cover the child with a blanket"; "cover the grave with flowers"
spread over a surface to conceal or protect; "This paint covers well"
undergo a test; "She doesnt test well"
any standardized procedure for measuring sensitivity or memory or intelligence or aptitude or personality etc; "the test was standardized on a large sample of students" (同)mental test, mental testing, psychometric test
the act of undergoing testing; "he survived the great test of battle"; "candidates must compete in a trial of skill" (同)trial
the act of testing something; "in the experimental trials the amount of carbon was measured separately"; "he called each flip of the coin a new trial" (同)trial, run
a hard outer covering as of some amoebas and sea urchins
put to the test, as for its quality, or give experimental use to; "This approach has been tried with good results"; "Test this recipe" (同)prove, try, try out, examine, essay
achieve a certain score or rating on a test; "She tested high on the LSAT and was admitted to all the good law schools"
determine the presence or properties of (a substance)
show a certain characteristic when tested; "He tested positive for HIV"
remove all or part of ones clothes to show ones body; "uncover your belly"; "The man exposed himself in the subway" (同)expose
make visible; "Summer brings out bright clothes"; "He brings out the best in her" (同)bring_out, unveil, reveal
an artifact that covers something else (usually to protect or shelter or conceal it)
the act of protecting something by covering it
a natural object that covers or envelops; "under a covering of dust"; "the fox was flushed from its cover" (同)natural covering, cover
an examination of the characteristics of something; "there are laboratories for commercial testing"; "it involved testing thousands of children for smallpox"
the act of subjecting to experimental test in order to determine how well something works; "they agreed to end the testing of atomic weapons"

PrepTutorEJDIC

(…で)…‘の'『表面をおおう』,'を'包む,かぶせる《+『名』+『with』+『名』》 / (範囲が)…‘に'『及ぶ』,わたる,'を'取り扱う範囲に入れる / 〈ある距離〉'を'行く,進む(受動態にできない) / …‘に'保険を掛ける / …'を'報道する,取材する / 〈要塞・砲などが〉'を'制圧する / (ピストルなどで)〈人〉'を'ねらう《+『名』+『with』+『名』》 / (球技などで)〈相手〉の動きなど〉'を'ふせぐ;〈地域など〉'を'守る / (…の)代役をする,身代りをする《+『for』+『名』》 / 〈C〉『おおい』,包むもの,カバー;ふた / 〈C〉『表紙』 / 〈U〉隠れ場所,潜伏所 / 〈U〉姿を隠してくれるもの(暗闇,煙など) / 〈C〉(秘密を隠すための)見せかけ / 〈U〉(…の)保険《+『against』+『名』》 / 〈C〉封筒;(郵便小包などの)包装紙 / 〈C〉毛布,ふとん
(人の能力などの)『試験』,考査,テスト / (物事の)『試験』,検済,試錬,実験《+of+名》 / 化学分析;試薬 / =test match / …‘を'『試験する』,検査する / …‘を'化学分析する / (…の)試験を受ける,試験をする《+for+名》
…‘の'『おおい』(ふた)『を取る』 / 〈秘密など〉‘を'『明らかにする』,暴露する / 《古》(敬意を表して)〈頭〉‘から'帽子を取る / (敬意を表して)脱帽する
〈U〉おおうこと;援護 / 〈C〉おおう物(布,ふた,屋根など)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2019/05/26 08:16:59」(JST)

wiki en

A cover test or cover-uncover test is an objective determination of the presence and amount of ocular deviation. It is typically performed by orthoptists, ophthalmologists and optometrists during eye examinations.

The two primary types of cover tests are:

the alternating cover test
the unilateral cover test (or the cover-uncover test).

The test involves having the patient (typically a child) focusing on a near object. A cover is placed over an eye for a short moment then removed while observing both eyes for movement. The misaligned eye will deviate inwards or outwards. The process is repeated on both eyes and then with the child focusing on a distant object.

The cover test is used to determine both the type of ocular deviation and measure the amount of deviation. The two primary types of ocular deviations are the tropia and the phoria. A tropia is a misalignment of the two eyes when a patient is looking with both eyes uncovered. A phoria (or latent deviation) only appears when binocular viewing is broken and the two eyes are no longer looking at the same object.

The unilateral cover test is performed by having the patient focus on an object then covering the fixating eye and observing the movement of the other eye. If the eye was exotropic, covering the fixating eye will cause an inwards movement; and esotropic if covering the fixating eye will cause an outwards movement. The alternating cover test, or cross cover test is used to detect total deviation (tropia + phoria).

Cover Test & Information Gained from the Cover Test

The cover test is regarded as an essential examination in investigating strabismus. It is simple to undertake, does not require great amounts of skill by the examiner and is objective in nature. To ensure that the test is executed accurately and that the maximal amount of information is obtained, it is paramount that the appropriate fixation targets are used for near (approximately 33 cm), distance (3m) and far distance (>3m) and also that a cover consisting of a black ‘paddle’ is used. A translucent occluder paddle may also be used. This enables the examiner to see the eye's position behind the occluder.^[1]

Many characteristics of a strabismus can be gained from performing the cover test.

In a Manifest Strabismus it can tell us the following:

- The type of deviation: whether it be eso, exo, hyper, hypo or cyclo tropia.
- The size of the deviation: slight, small, moderate or large
-Speed to take up fixation: if the eye takes up fixation fast it means there is good vision in that eye
-Accommodation on the deviation
- Nystagmus
-Dissociated vertical deviation (DVD)
- Incomitance – deviation angle varies in each position of gaze
^[2]

In a Latent Deviation it can tell us the following:

-Type of deviation: esophoria, exophoria, hyperphoria, hypophoria, cyclophoria
- Size of deviation
- Rate of recovery that enables the person to achieve binocular single vision. It also says a lot about the strength of control over the deviation.
^[2]

Fixation Targets

Fixation targets are required for both the near (33 cm) and far (6m) components of the cover test.

Near Targets (33 cm)

Light source – A penlight/light from retinoscope or ophthalmoscope could be used at the start of the near cover test assessment to observe the patient's corneal reflections, and to see whether their fixation is steady, central and maintained. Assessing the patient's fixation is especially important in those patients who suffer from amblyopia.^[1]

Detailed target – Any small object that has the ability to stimulate Accommodation (eye) and allow the examiner to assess the patient's fixation. For children, very small pictures like those seen on a Lang stick can be used. Whereas for adults a small Snellen chart letter or number can be used.^[1]

Distance Targets (6m)

Spotlight – In those patients with amblyopia a spotlight could be used. (Same as near targets).^[1]

Snellen chart – This is the most commonly used target when assessing a patient's far component of a cover test.^[1]

Small landmark – Any fixed landmark at eye level, which can be seen through a window.^[1]

Stationary Toy – Fixed, talking toys are often used in children when their fixation is difficult to obtain when assessing the far component of the cover test.^[1]

Note: That when using any of the targets above (near or far), it is vital that they are placed as close to the patient's eye level as possible. This will eliminate any inaccurate results. Also during the cover test, the examiner must make sure that the patient is clearly seeing the fixation targets to confirm their Accommodation (eye) is controlled.^[1]

Method

There are 2 parts to the Cover Test (CT), which include the cover and uncover component and the alternate cover test.

Prior to proceeding, ensure that there is sufficient light in the room so that the examiner can clearly see the patient's eyes.

Sit approximately 30 cm away from the patient to ensure you are able to observe their eye movement. Explain the purpose of the test to the patient, for example: “I am going to check how well your eye muscles are working together." ^[3]

The cover/uncover part includes 1 eye being covered. Instruction to the patient: “I would like you to look at this letter at near (examiner holds up the fixation target) or the clearest letter you can see at the other end of the room on the Snellen chart for distance testing. Keep watching the letter while I cover your eye.”^[3]

The examiner observes:

The movement of the uncovered eye taking up fixation ^[1]
The movement as well as position of the eye under the cover when the paddle is removed (repeat until you can observe a movement/no movement to confirm a diagnosis)^[1]
Cover/uncover method looks for heterotropia

The alternate CT has to ensure that one eye is dissociated at all times:

The movement of the covered eye is recorded as the paddle is changed from one eye to the other every 3 seconds while allowing the eye to take up fixation ^[1]
Place the cover before the first eye in a manner that prevents the patient from viewing the target but allows you to continue seeing the covered eye ^[3]
Observe the response of the first eye tested behind the occluder when it is first covered ^[3]

Note: The cover/uncover component of the test is less dissociating than the alternate CT. The alternate CT can't distinguish between manifest and latent deviations. When measuring in the distance ensure you are not blocking the patient's view of the fixation target.^[1]

Practical Application

Stages in the detection of a manifest deviation

When a patient has a manifest strabismus the uncovered eye will take up fixation when the fixing eye is covered.

The cover/ uncover test is performed at near using a flashlight as a target. Shining a light in the patient's eye allows the orthoptist to observe their corneal reflection. When the eyes are straight the corneal reflections will be located centrally in each pupil. When the patient has a deviation one corneal reflection will be in the centre of the pupil and the other reflection will be on or close to the iris. When detecting a manifest deviation the Orthoptist covers the straight eye if a deviation is apparent or the eye with the better VA. Observe the behaviour of the uncovered eye.^[4]

This procedure is now repeated with an accommodative target. Ask the patient to look at a fixation stick that has a picture or a letter and observe the deviation at near and distance.^[1]

An alternate cover test is performed to ensure full dissociation, observe any changes in the amount and type of movement.^[1]

Lastly, repeat the cover/uncover test and note whether the eye remains deviated or returns to its original position.^[1]

Stages in the detection of a latent deviation

When searching for a latent deviation our attention is directed to the covered eye. When performing the cover/uncover test the uncovered eye does not move; however the eye that is under the cover will deviate and return to a straight position when the cover is removed.

The uncover/cover test is also performed at near and distance with an accommodative target. Once a cover/uncover test has been performed to confirm the presence of a manifest deviation our attention is turned to the behavior of the covered eye. It is important that when observing the covered eye look at the speed and recovery of the eye when the cover is removed.^[1]

An alternate cover test is also performed and this provides information about the maximum deviation. The speed that the eye recovers indicates the patient's control over the deviation. The faster the recovery the better control the patient has over the deviation.^[1]

Finally, a cover/uncover test must be performed again to ensure the deviation has remained latent and recovery is the same.^[1]

Precautions

Cautions to be noted in avoidance of misdiagnoses /contamination of results

It is important to avoid prolonged periods of dissociation of the eyes until a diagnosis can be made regarding the strabismus.

Hence, the importance to note that although the eyes require dissociation for a minimum of three seconds, that dissociation is kept minimal whilst fixation is maintained. The cover test should be considered prior to testing VA patients with strabismus, for occlusion during testing may dissociate an unstable ocular deviation. In the case of intermittent or latent deviations, for dissociative complications leading to misdiagnosis, it is also advised that binocular vision is tested prior, along with stereo testing.^[1]

Frequently, during testing, the cover can be removed prematurely; therefore, as mentioned earlier, dissociation of at least three seconds is needed for the patient to take up fixation during cover testing. This time allows for patients to recover from dissociation post cover removal.

A penlight should be used to observe the steadiness and positioning of the deviated eye.

Ensure to assist the patient in maintaining fixation on accommodative or distance targets at all times - if testing on children or adults, request specific details pertaining to the accommodative target (to assure accommodation is utilized) for near testing. Use of a detailed target for near fixation in both adults and children will identify the effects of accommodation on the deviation. Observing pupillary constriction should also be indicative of accommodation.

Cover-Uncover testing and alternate cover testing should be performed on the deviating eye even when a constant heterotropia is observed. This practice ensures the detection of a consistent increase in deviation and DVD isn't neglected.^[1]

The presence of orthophoria in uncommon when assessing both near and far fixation. VA must be considered when there is no deviation seen upon cover testing given amblyopic eyes may not take up fixation (VA too poor to see target or eccentric fixation).

Microtropia may be present when a small unequal VA is recorded.^[1]

Recording

The cover test results must be recorded in a clear and brief manner. The information included should include the following:

Type of deviation present: manifest or latent deviation ^[1]
Direction of the deviation: horizontal, vertical or a combination of both
Estimation of size: the examiner will observe the position of the corneal reflections and the amount of movement shown to take up fixation
In latent deviations the speed of recovery is noted: it can be described as rapid, moderate, delayed or blink (the blink regains fusion). If diplopia is noted before recovery this should also be recorded
The distance the test was performed - whether it was at near (1/3m) or distance (6m)
Whether the test was performed with/without glasses
Whether the test was performed with/without a compensatory head posture
In a poorly controlled phoria recovery may not occur and the deviation will be manifest - make a note of this also

Examples of a cover test recording: ^[1]

CT: cc sml LXT/XT’ nhf

CT: sc mod E/E’ c r.r

CT: cc RET holds fixation

RE(T)’ holds fixation

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w Ansons, A.M; Davis, H (2014). Diagnosis and Management of Ocular Motility Disorders (4th ed.). London: Blackwell.
^ ^a ^b Rowe, Fiona. J (2012). Clinical Orthoptics (3rd ed.). Wiley. p. 64. ISBN 9781444339345.
^ ^a ^b ^c ^d David B.Elliott. (2013). Clinical Procedures in Primary Eye Care. Retrieved from https://www.inkling.com/read/elliott-clinical-procedures-primary-eye-care-4th/chapter-6/6-2-the-cover-test
^ Helveston, Eugene (2010). "Understanding, detecting, and managing strabismus". Community Eye Health/International Centre for Eye Health. 23: 12–14.

UpToDate Contents

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1. 小児における斜視の評価およびマネージメントevaluation and management of strabismus in children [show details]
…can overlook small deviations, it should be used in conjunction with the cover test and the cover/uncover test. The cover test is one of the most important tests used in the detection of manifest strabismus …
2. 乳児や小児の視力スクリーニング検査と評価vision screening and assessment in infants and children [show details]
…the other is a matter of personal preference. In the CSM notation, with one eye occluded (the cover test), several characteristics of fixation are noted: Is the fixation central (C) or eccentric/noncentral…
3. 小児における身体的診察：HEENTthe pediatric physical examination heent [show details]
…outwardly displaced, it is esotropic; and if inferiorly displaced, it is hypertropic . The cover-uncover eye test is a more accurate test for ocular alignment in the cooperative patient. Testing is done…
4. 予防のためのエビデンスに基づいたアプローチevidence based approach to prevention [show details]
5. 小児における後天性斜頚acquired torticollis in children [show details]
…ocular torticollis should be evaluated as follows: The corneal light reflex test and the cover/uncover test should be performed to determine whether the child has strabismus or superior oblique palsy…

English Journal

Alcohol Use and Positive Screening Results for Depression and Anxiety Are Highly Prevalent among Chinese Children with Strabismus.

Lin S1, Congdon N2, Yam JC3, Huang Y1, Qiu K1, Ma D1, Chen B1, Li L4, Zhang M5.Author information 1Joint Shantou International Eye Center of Shantou University and Chinese University of Hong Kong, Shantou, Guangdong Province, China, 515041.2Zhongshan Ophthalmic Centre, Sun Yat Sen University, State Key Laboratory and Division of Preventive of Ophthalmology, Guangzhou, China, 510060.3Joint Shantou International Eye Center of Shantou University and Chinese University of Hong Kong, Shantou, Guangdong Province, China, 515041; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Hong Kong, China.4Medical College of Shantou University, Shantou, Guangdong Province, China, 515041.5Joint Shantou International Eye Center of Shantou University and Chinese University of Hong Kong, Shantou, Guangdong Province, China, 515041. Electronic address: bob239@163.com.AbstractPURPOSE: To study associations between strabismus and alcohol use, anxiety and depression among 10-17-year-old children in Guangdong, southern China.
American journal of ophthalmology.Am J Ophthalmol.2014 Jan 17. pii: S0002-9394(14)00022-1. doi: 10.1016/j.ajo.2014.01.012. [Epub ahead of print]
PURPOSE: To study associations between strabismus and alcohol use, anxiety and depression among 10-17-year-old children in Guangdong, southern China.DESIGN: Cross-sectional, population-based study METHODS: Among 7537 children aged 6 to 17 years from 9 randomly-selected primary and middle schools, oc
PMID 24445033

Prevalence and pattern of refractive errors among primary school children in Al Hassa , Saudi Arabia.

Al Wadaani FA, Amin TT, Ali A, Khan AR.Author information Faculty of Medicine, Cairo University, Cairo, Egypt.AbstractSome 12.8 million in the age group 5-15 years are visually impaired from uncorrected or inadequately corrected refractive errors. In Saudi Arabia, the size of this public health problem is not well defined especially among primary schoolchildren. The purpose of this cross-sectional study was to assess the prevalence and pattern of refractive errors among primary school children in Al Hassa, Saudi Arabia. A total of 2246 Saudi primary school children aged 6 to 14 years of both genders were selected using multistage sampling method form 30 primary schools located in the three different areas of Al Hassa. School children were interviewed to collect demographics and vision data using a special data collection form followed by screening for refractive errors by trained optometrists within the school premises using a standardized protocol. Assessment of visual acuity and ocular motility evaluation were carried out and cover-uncover test was performed. Children detected with defective vision were referred for further examination employing subjective refraction with auto refractometer and objective refraction using streak retinoscopy after 1% cyclopentolate. Of the screened school children (N=2002), the overall prevalence of refractive errors was 13.7% (n=274), higher among females (Odds ratio, OR=1.39, P=0.012) and significantly more among students of rural residence (OR=2.40, P=0.001). The prevalence of refractive errors was disproportionately more among those aged 12-14 years (OR=9.02, P=0.001). Only 9.4% of students with poor vision were wore spectacles for correction. Myopia was the most commonly encountered refractive error among both genders (65.7% of the total errors encountered). Uncorrected refractive errors affected a sizable portion of primary school children in Al Hassa, Saudi Arabia. Primary schoolchildren especially females, rural and older children represents high risk group for refractive errors for which the included children were unaware.
Global journal of health science.Glob J Health Sci.2012 Nov 11;5(1):125-34. doi: 10.5539/gjhs.v5n1p125.
Some 12.8 million in the age group 5-15 years are visually impaired from uncorrected or inadequately corrected refractive errors. In Saudi Arabia, the size of this public health problem is not well defined especially among primary schoolchildren. The purpose of this cross-sectional study was to asse
PMID 23283044

Saccades and vergence performance in a population of children with vertigo and clinically assessed abnormal vergence capabilities.

Bucci MP, Kapoula Z, Bui-Quoc E, Bouet A, Wiener-Vacher S.Author information Laboratoire de Psychologie et Neuropsychologie Cognitives, FRE 3292 CNRS IUPDP Université Paris Descartes, Boulogne Billancourt, France. maria-pia.bucci@parisdescartes.frAbstractPURPOSE: Early studies reported some abnormalities in saccade and vergence eye movements in children with vertigo and vergence deficiencies. The purpose of this study was to further examine saccade and vergence performance in a population of 44 children (mean age: 12.3±1.6 years) with vertigo symptoms and with different levels of vergence abnormalities, as assessed by static orthoptic examination (near point of convergence, prism bar and cover-uncover test).
PloS one.PLoS One.2011;6(8):e23125. doi: 10.1371/journal.pone.0023125. Epub 2011 Aug 9.
PURPOSE: Early studies reported some abnormalities in saccade and vergence eye movements in children with vertigo and vergence deficiencies. The purpose of this study was to further examine saccade and vergence performance in a population of 44 children (mean age: 12.3±1.6 years) with vertigo sympt
PMID 21858007

Japanese Journal

眼位異常スクリーニングのための定性的な眼位検査システムの開発

平田木乃美,日隈光基,高塚佳代子,山場久昭,油田健太郎,岡崎直宣
宮崎大學工學部紀要 47, 305-309, 2018-07
… Specifically, "Cover-Uncover function" which is the elemental technology necessary for the automation of the typical " Cover Test" for eye position check was digitalized. …
NAID 120006501570

眼位異常のスクリーニングのための定性的な眼位検査システムに関する研究

平田木乃美,日隈光基,高塚佳代子,山場久昭,油田健太郎,岡崎直宣
宮崎大學工學部紀要 47, 291-303, 2018-07
… Specifically, the digitalization of element technology, "Cover-uncover function", was conducted necessary for the automation of the typical "Cover Test" for eye position check. … And we also implemented function to detect movement indicating an ocular malalignment from eyeball videos durign Cover test. …
NAID 120006501569