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Screening for refractive errors with the Topcon PR2000 Pediatric Refractometer
1Dept. of Ophthalmology, Bristol Eye Hospital, United Kingdom. cathy.williams@bristol.ac.uk
Insights
The PR2000 photorefractor accurately screens preschool children for refractive errors like anisometropia, though it underestimates hypermetropia without cycloplegia. Its repeatability is good for sphere and acceptable for astigmatism.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Vision Science
Background:
- The PR2000 is a photorefractor used for screening preschool children's vision.
- Previous studies have compared different screening methods in this age group.
Purpose of the Study:
- To evaluate the accuracy of the PR2000 photorefractor in a clinical setting with children under 8 years old.
- To compare the PR2000's performance against cycloplegic retinoscopy.
Main Methods:
- 222 children under 8 years underwent PR2000 examination without cycloplegia.
- All participants subsequently had retinoscopy performed with cycloplegia by an independent examiner.
Main Results:
- The PR2000 provided readings for 90% of eyes, with 5% out of range.
- It underestimated hyperopic refractive errors and astigmatism compared to retinoscopy.
- Sensitivity and specificity for anisometropia detection were 91% and 92%, respectively.
- Repeatability was good for sphere (ICC=0.74) and moderate for astigmatism (ICC=0.59).
Conclusions:
- The PR2000 is a valuable screening tool, particularly for detecting anisometropia.
- It demonstrates good repeatability for refractive error measurements.
- The device underestimates hyperopic errors when cycloplegia is not used.
Purpose:
The PR2000 (Topcon, Tokyo, Japan) is a photorefractor that has been used in a population study comparing different methods of screening preschool children. The present study was conducted to determine the accuracy of the device in a largely clinical population.
Methods:
Two hundred twenty-two children less than 8 years of age were included. All children were examined by an orthoptist using the PR2000 without inducing cycloplegia. All children then underwent retinoscopy with cycloplegia by an examiner who was unaware of the results from the PR2000 examination.
Results:
The PR2000 gave a numerical reading for 90% of the children's right eyes and the message "Out of range" for a further 5%. The readings underestimated the amount of hypermetropic or astigmatic refractive error found on retinoscopy by an amount proportional to the magnitude of the refractive error. Agreement with retinoscopy for the axis of astigmatism more than 0.75 D was moderately good (intraclass correlation coefficient [ICC] = 0.63). The PR2000 was more useful as a screener, especially for anisometropia for which it was 91% sensitive and 92% specific. The repeatability was good for sphere (ICC = 0.74), less so for astigmatism (ICC = 0.59), and better than the optometrist for anisometropia (ICC = 0.38). The presence of nonrefractive diagnoses and the age of the children examined made little difference in the screening results.
Conclusions:
The PR2000 underestimated hypermetropic refractive errors when used without cycloplegia. However, it was at least as good a screening device as other similar instruments, especially when judged by its ability to detect anisometropia and the repeatability of the results.