Infrared Choroidal Reflectance Camera for the Detection of Childhood Cataract

Study Overview
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Brief Summary
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Sensitivity and specificity of current screening methods for childhood cataracts is poor. This results in delayed diagnosis and management which can decrease the visual prognosis following cataract surgery. It also results in many false positives with resultant unnecessary healthcare costs in specialist paediatric ophthalmology services. This study compares the accuracy of cataract screening using infrared light compared to white light in a population of children attending eye clinic.

Detailed Description
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All babies born in the United Kingdom (UK) undergo eye screening to enable the early diagnosis and management of childhood cataract, a treatable but potentially blinding condition affecting 1 in 2000 newborns. The current technique involves the assessment of the red-reflex - the orange/red glow in the pupil seen during ophthalmoscopy (or flash photography) due to reflectance of light from the back of the eye. In reality, testing can be technically difficult because the pupil constricts to light during the examination and, particularly in babies of Asian and Afro-Caribbean ancestry, the red-reflex can be dim due to the effect of ocular pigmentation. As a result less than 50% of congenital cataracts are currently identified up by screening. Early visual experience is required for good visual development and a delay in the surgical management of cataracts results in sub-optimal visual development and visual impairment. There are theoretical advantages to using Infrared (IR) light rather than white light to assess choroidal reflectance, including avoidance of pupil constriction. The study aims to determine if the assessment of the IR-reflex, using a prototype device, rather than the red-reflex, using a direct ophthalmoscope, improves screening accuracy in the detection of ocular media opacities in a pathology enriched childhood cohort. Eligible children attending an eye clinic will be screened for cataract by a medical student (masked to the pathology) using the existing standard direct ophthalmoscope technique for red-reflex assessment and IR-reflex assessment using the prototype imaging device. A gold standard examination by an ophthalmologist will follow the screening examinations. Sensitivity and specificity of each screening technique will be calculated and compared.

Official Title
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Proof of Concept Trial of a Novel Imaging System to Assess and Document Choroidal Reflectance in Children for the Detection of Cataract and Media Opacities.

Conditions
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Childhood Cataract

Intervention / Treatment
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* Diagnostic Test: Red-reflex assessment
* Diagnostic Test: Infrared-reflex assessment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All children between 1 month and 5 years of age attending paediatric ophthalmology clinic Exclusion Criteria: Parents / carers with poor conversant English

Ages Eligible for Study
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Minimum Age: 1 Month
Maximum Age: 5 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children attending eye clinic<br>Children 1 month to 5 years of age attending paediatric ophthalmology clinic with and without cataracts. Children who had previously had intra-ocular surgery were excluded. One eye of each child was assessed by an inexperienced screener (medical student) by red-reflex assessment using direct ophthalmoscope and infrared-reflex using a new device (CatCam). CatCam is a modified smart phone camera which images the reflection of co-axial infrared light from the ocular fundus. A cataract appears as a black silhouette on the white infrared-reflex imaged by the camera. Sensitivity and specificity for red-reflex and infrared-reflex assessment compared to gold standard dilated ophthalmic examination by a specialised were compared. | Diagnostic Test: Red-reflex assessment<br>* The red reflex was examined in the standard manner using direct ophthalmoscope by medical student examiner<br>Diagnostic Test: Infrared-reflex assessment<br>* The infrared reflex was examined using a modified smart phone camera by a medical student examiner<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Results of Red-reflex and Infrared-reflex Tests Compared to Gold Standard | True positives: the number of eyes with cataract correctly identified True negatives: the number of eyes without cataract correctly identified False positives: the number of eyes without cataracts incorrectly identified as having cataract False negatives positives: the number of eyes with cataract incorrectly identified as not having cataract | 1 day | 
| Sensitivity and Specificity of Red-reflex and Infrared-reflex Testing | Sensitivity (percentage of eyes with cataract correctly identified) and specificity (percentage of eyes without cataract correctly identified) of red-reflex and infrared-reflex testing in percentage terms with 95% Confidence Intervals. Sensitivity and specificity are recorded as a percentage, with 100% indicating best accuracy. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Results of Red-reflex and Infrared-reflex Tests Compared to Gold Standard Stratified by Ethnicity | True positives: the number of eyes with cataract correctly identified in caucasian children's eyes and in BAME children's eyes. True negatives: the number of eyes without cataract correctly identified in caucasian children's eyes and in BAME children's eyes. False positives: the number of eyes without cataract incorrectly identified as having cataract in caucasian children's eyes and in BAME children's eyes. False negatives: the number of eyes with cataract incorrectly identified as not having cataract in caucasian children's eyes and in BAME children's eyes. | 1 day | 
| Sensitivity and Specificity of Red-reflex and Infrared-reflex Testing Stratified by Ethnicity | Sensitivity (percentage of eyes with cataract correctly identified) and specificity (percentage of eyes without cataract correctly identified) of red-reflex and infrared-reflex testing in percentage terms with 95% Confidence Intervals. Sensitivity and specificity are recorded as a percentage, with 100% indicating best accuracy. | 1 day |