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Correlation of Nidek OPD-Scan objective refraction with subjective refraction
Ian Y L Yeung1, Sanjay Mantry, Ian A Cunliffe
1Midland Eye Institute, West Midlands, UK.
Journal of Refractive Surgery (Thorofare, N.J. : 1995)
|November 4, 2004
Summary
The Nidek OPD-Scan shows good correlation with subjective refraction for myopia and astigmatism. This objective refraction tool is reliable for pre-operative measurements before refractive surgery like LASIK.
Area of Science:
- Ophthalmology
- Optometry
- Refractive Surgery
Background:
- Accurate pre-operative refractive measurements are crucial for successful refractive surgery.
- Objective refraction devices aim to provide precise measurements efficiently.
Purpose of the Study:
- To evaluate the correlation between Nidek OPD-Scan objective refraction and subjective refraction.
- To quantify the agreement for sphere, cylinder, and spherical equivalent measurements.
Main Methods:
- Retrospective audit of 80 eyes undergoing myopic LASIK or LASEK.
- Nidek OPD-Scan used for objective refraction (5-mm zone).
- Subjective refraction performed by a senior optometrist; statistical analysis conducted.
Main Results:
- High correlation for sphere (R=0.97) and spherical equivalent (R=0.97).
- Moderate correlation for cylinder (R=0.85).
- Majority of measurements differed by only 0.50 D.
Conclusions:
- Nidek OPD-Scan demonstrates good agreement with subjective refraction.
- Especially strong correlation for sphere and spherical equivalent.
- Supports the use of OPD-Scan for pre-operative assessment in refractive surgery.