Internal Astigmatism Measurement; Testing a Theory
Journal of Ophthalmic and Optometric Sciences,
Vol. 8 No. 2 (2024),
2 April 2024
,
Page 1-6
https://doi.org/10.22037/joos.v8i2.47596
Abstract
Purpose: To determine refraction and corneal astigmatism using an ophthalmometer and to calculate the difference between the two to obtain the mean internal astigmatism.
Patients and Methods: This study included 45 patients. Inclusion criteria required participants to be 18 years or older with astigmatism. Manifest refraction was measured at least five times per eye using a Topcon RM-8900 autorefractometer and then confirmed by retinoscopy. Patients were subsequently examined with a Topcon Ophthalmometer and the results were recorded.
Results: The mean internal astigmatism values were approximately equal for the right (-0.5333 D) and left eyes (-0.5722 D). The mean amplitude of accommodation values were also similar for the right (9.2333 D) and left (9.0444 D) eyes. No correlation was found between internal astigmatism and amplitude of accommodation.
Conclusion: The mean internal astigmatism values obtained for the right and left eyes were consistent with Javal’s hypothesis, supporting its validity. No significant difference in the distribution of internal astigmatism was observed between the two eyes. Additionally, no correlation was found between internal astigmatism and the amplitude of accommodation.
- Astigmatism
- Refraction
- Keratometry
How to Cite
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