Abstract
BACKGROUND:
Ocular astigmatism is the sum of corneal astigmatism and internal astigmatism. The component of ocular astigmatism that cannot be a attributed to the anterior corneal surface is referred to as ocular residual astigmatism.
OBJECTIVE:
To evaluate the difference between ocular residual astigmatism and total ocular residual astigmatism in normal virgin eyes with refractive errors.
PATIENTS AND METHODS:
Eighty four patients ( 135 virgin eyes) with refractive errors were enrolled consecutively in this study at the Lasik clinic in Ibn Al- Haitham Teaching Eye Hospital. Measurement of astigmatism was done by
manifest refraction and corneal topography using Oculus Pentacam, and these measurements were used for calculating ocular residual astigmatism and total ocular residual astigmatism with comparison between them.
RESULTS:
The study showed a significant difference between the means of ocular residual astigmatism (-0.7416 ± 0.4341 ) and the total ocular residual astigmatism (-0.6223 ± 0.401) in with the rule astigmatism (P value < 0.001), and the means of ocular residual astigmatism (-0.8113 ± 0.38517) versus the means
of total ocular residual astigmatism (-0.6658 ± 0.3844) in against the rule astigmatism (P value <0.001).
CONCLUSION:
The ocular residual astigmatism based on the total corneal topographic astigmatism corresponds better with manifest refractive cylinder than the ocular residual astigmatism based solely on anterior corneal
topographic astigmatism .
KEY WORDS: Ocular residual astigmatism, Posterior corneal astigmatism.
ABSTRACT:
BACKGROUND:
Ocular astigmatism is the sum of corneal astigmatism and internal astigmatism. The component of ocular astigmatism that cannot be a attributed to the anterior corneal surface is referred to as ocular residual astigmatism.
OBJECTIVE:
To evaluate the difference between ocular residual astigmatism and total ocular residual astigmatism in normal virgin eyes with refractive errors.
PATIENTS AND METHODS:
Eighty four patients ( 135 virgin eyes) with refractive errors were enrolled consecutively in this study at the Lasik clinic in Ibn Al- Haitham Teaching Eye Hospital. Measurement of astigmatism was done by
manifest refraction and corneal topography using Oculus Pentacam, and these measurements were used for calculating ocular residual astigmatism and total ocular residual astigmatism with comparison between them.
RESULTS:
The study showed a significant difference between the means of ocular residual astigmatism (-0.7416 ± 0.4341 ) and the total ocular residual astigmatism (-0.6223 ± 0.401) in with the rule astigmatism (P value < 0.001), and the means of ocular residual astigmatism (-0.8113 ± 0.38517) versus the means
of total ocular residual astigmatism (-0.6658 ± 0.3844) in against the rule astigmatism (P value <0.001).
CONCLUSION:
The ocular residual astigmatism based on the total corneal topographic astigmatism corresponds better with manifest refractive cylinder than the ocular residual astigmatism based solely on anterior corneal
topographic astigmatism .
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