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INSTRUMENT CORNER
Year : 2018  |  Volume : 30  |  Issue : 1  |  Page : 58-60

Photoscreening devices


Giridhar Eye Institute, Kochi, Kerala, India

Date of Web Publication7-Jun-2018

Correspondence Address:
R Neena
Senior Consultant and Head of Department, Department of Paediatric Ophthalmology and Strabismus, Giridhar Eye Institute, Kochi - 682 020, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kjo.kjo_22_18

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How to cite this article:
Manju M, Neena R. Photoscreening devices. Kerala J Ophthalmol 2018;30:58-60

How to cite this URL:
Manju M, Neena R. Photoscreening devices. Kerala J Ophthalmol [serial online] 2018 [cited 2018 Sep 19];30:58-60. Available from: http://www.kjophthal.com/text.asp?2018/30/1/58/233778


  Introduction Top


Ophthalmological screening in pediatric population is primarily aimed at early detection of refractive errors, ocular alignment problems, and any opacities in the media. Early detection of these factors is important for the prevention of development of amblyopia in children. Infants and young preverbal children are often unable to provide adequate responses to subjective tests of visual acuity and do not easily cooperate for tests of ocular alignment or stereopsis. It is also difficult to screen certain older children, such as those who are nonverbal or have developmental delay. Hence, the use of a less time-consuming device which needs only minimum collaboration from the patients is essential. Photoscreening devices come under this criterion.

Photoscreening devices or photorefractors function based on the analysis of a reflected image from the patient's retina. An infrared camera contained in these devices captures the images of red reflex and images of the corneal light reflex from a child's pupil. The test is performed binocularly, and based on the reflexes, an examiner or a computer program can analyze to determine if there is strabismus and/or significant refractive error. Photoscreeners can also detect other anatomical abnormalities, including cataract, coloboma, or ptosis. The test is fast and usually takes less than a minute and can be performed on both verbal and preverbal children. This method is also much faster than acuity screening, but unlike autorefractive screening, it can directly screen for manifesting strabismus.

In adults, photoscreeners may be used in refractive error screening camps, improving access to ocular health-care services for socioeconomically disadvantaged populations.

Photoscreening devices can be used even in undilated pupil and is less time-consuming in nature. Since it is an objective assessment device, person-to-person variability in ocular morbidity assessment is very less. Hence, even a nonmedical person can use the device for screening purpose and do a proper referral. These devices can increase the detection rates of visual morbidities in children and thus help in timely management to prevent amblyopia.

There are different types of photoscreeners, and some of them currently in use are given below.


  Iscreen Top


It was introduced in 2006. It is an eccentric, binocular photoscreening device that captures an image. This image can be transmitted and interpreted in a distant site. iScreen 3000 [Figure 1] and [Figure 2] is the currently available model, which is smaller sized and redesigned version of the previous model. It is a handheld device, which takes 2 photos in 2 axes 90 degrees apart. There is an aiming fixation light and sound to attract child's attention. Two images can be taken rapidly and in succession. These images appear on the screen immediately after capture. They can be assessed and repeated, if needed. Images are transferred to the analysis center and analyzed by experts. The report will be send back through E-mail to the screening center. The report contains details of the child's ocular status and need for follow-up or reference. It also includes a photo of child's eye.
Figure 1: I Screen

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Figure 2: Examination using I Screen

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  Spot Vision Screener (Welch Allyn) Top


It is a handheld device [Figure 3] and [Figure 4] operated at a distance of 1 m to detect vision difficulties in patients from 6 months of age. Using infrared light, it can test vision binocularly within seconds of time. It is a portable handheld device [Figure 5] in which pattern source light and sounds are used for diverting child's attention. It can detect refractive error, ocular alignment, and size of the pupil and also provide a photograph of the eye.
Figure 3: Welch Allyn spot vision screener

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Figure 4: Data obtained from Welch Allyn spot vision screener

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Figure 5: Examination using spot vision screener

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All the data can be stored in the device and can be used to assess prognosis or for research purpose. Device is based on American Academy of Pediatrics (AAP) screening criteria; red color coding is used to denote children who require referral and blue color is used to denote those who have completed the test normally. It also has WiFi facility and data-transferring facility.


  Mti Screener Top


It was developed by Jeremy Feakins and Howard Freedman. It got FDA approval in 1995. It has an aiming beam and fixation light. Using a polaroid light, two images are taken consecutively, and by analyzing these photographs, the child's refractive errors and ocular alignment are detected [Figure 6] and [Figure 7].
Figure 6: MTI photoscreener

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Figure 7: Photograph obtained from MTI photoscreener

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  Plusoptix Top


It uses an infrared recorder that records ocular reflection in 3 axes. These images can be used to calculate refractive errors and is compared with a referral guideline. A photograph and a report stating whether the patient needs to be referred or not is obtained. Referral criteria also include conditions of strabismus, anisocoria, or coloboma. Plusoptix may take a longer time for capturing of images. It can be a problem in very young and uncooperative children. It is a desktop device [Figure 8] and [Figure 9] with a handheld gun-like detector attached to it. It has a smiling face on which the child focuses and there is sound to get child's attraction. It produces an image of the child when the child focuses maximum and refractive errors are detected from this image.
Figure 8: Plusoptix

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Figure 9: Examination using Plusoptix

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In its policy statement, the AAP and the American Academy of Pediatric Ophthalmology and Strabismus advocate instrument-based screening, if available, to be first attempted between 12 months and 3 years of age and at annual well-child visits until acuity can be tested directly. It is also noteworthy that the US Preventive Services Task Force now actively recommends vision screening at least once for children between 36 months and 5 years and specifically mentions photoscreening as an appropriate screening technology.[1],[2],[3]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Committee on Practice and Ambulatory Medicine and Section on Ophthalmology, American Academy of Pediatrics. Use of photoscreening for children's vision screening. Pediatrics 2002;109:524-5.  Back to cited text no. 1
    
2.
US Preventive Services Task Force. Vision screening for children 1 to 5 years of age: US Preventive Services Task Force Recommendation Statement. Pediatrics 2011;127:340-6.  Back to cited text no. 2
[PUBMED]    
3.
Visual system assessment in infants, children, and young adults by pediatricians: Committee on practice and ambulatory medicine, section on ophthalmology, American Association of Certified Orthoptists, American Association for Pediatric Ophthalmology and Strabismus, American Academy of Ophthalmology, American Academy of Pediatrics. Pediatrics 2016;137:29.  Back to cited text no. 3
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]



 

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  In this article
Introduction
Iscreen
Spot Vision Scre...
Mti Screener
Plusoptix
References
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