Abstract
Purpose. In investigations of polarized light propagation through cornea, the stromal lamellae can be considered as a stack of birefringent plates. Theory shows that such a stack is optically equivalent to two optical elements in series - a polarization rotator followed by a single birefringent plate.1 Previous experimental investigations of corneal birefringence have not recognized the rotator component. The purpose of this study was to confirm the existence of the rotator component and measure its strength. Methods. Cross-polarized transmission (I+ transmission) was measured in perfused eye bank and freshly excised rabbit corneas as the incident polarization direction, θ, was rotated through 360°. After locating θmin, the angle at which I+ transmission is minimum, the incident polarization and analyzer directions were systematically varied from their crossed configuration in the neighborhood of θmin to locate the settings that produced the absolute minimum transmission. The angular deviation of these settings from 90°, ω, is the rotation induced by the rotator component. Results. The existence of a polarization rotator component was confirmed in both human and rabbit cornea. In human ω varied between -2.0 and +2.4° (n=5) and in rabbit ω varied between -1.6 and -0.1° (n=6). As predicted in Reference 1, the percentage difference between I+min and the absolute minimum transmission is directly proportional to sin2 ω (R=0.99 for both human and rabbit). Conclusions. These results provide further confirmation of the validity of the modeling methods introduced in Ref. 1. Such methods, when combined with polarization experiments, allow one to determine features of lamellar structure that are important to understanding mechanical properties of the cornea.
| Original language | English (US) |
|---|---|
| Journal | Investigative Ophthalmology and Visual Science |
| Volume | 37 |
| Issue number | 3 |
| State | Published - Feb 15 1996 |
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ASJC Scopus subject areas
- Ophthalmology
Cite this
Birefringence properties of human and rabbit cornea : Polarization rotation component. / McCally, R. L.; Green, W. J.; Christens-Barry, W. A.; Donohue, D. J.; Farrell, R. A.
In: Investigative Ophthalmology and Visual Science, Vol. 37, No. 3, 15.02.1996.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Birefringence properties of human and rabbit cornea
T2 - Polarization rotation component
AU - McCally, R. L.
AU - Green, W. J.
AU - Christens-Barry, W. A.
AU - Donohue, D. J.
AU - Farrell, R. A.
PY - 1996/2/15
Y1 - 1996/2/15
N2 - Purpose. In investigations of polarized light propagation through cornea, the stromal lamellae can be considered as a stack of birefringent plates. Theory shows that such a stack is optically equivalent to two optical elements in series - a polarization rotator followed by a single birefringent plate.1 Previous experimental investigations of corneal birefringence have not recognized the rotator component. The purpose of this study was to confirm the existence of the rotator component and measure its strength. Methods. Cross-polarized transmission (I+ transmission) was measured in perfused eye bank and freshly excised rabbit corneas as the incident polarization direction, θ, was rotated through 360°. After locating θmin, the angle at which I+ transmission is minimum, the incident polarization and analyzer directions were systematically varied from their crossed configuration in the neighborhood of θmin to locate the settings that produced the absolute minimum transmission. The angular deviation of these settings from 90°, ω, is the rotation induced by the rotator component. Results. The existence of a polarization rotator component was confirmed in both human and rabbit cornea. In human ω varied between -2.0 and +2.4° (n=5) and in rabbit ω varied between -1.6 and -0.1° (n=6). As predicted in Reference 1, the percentage difference between I+min and the absolute minimum transmission is directly proportional to sin2 ω (R=0.99 for both human and rabbit). Conclusions. These results provide further confirmation of the validity of the modeling methods introduced in Ref. 1. Such methods, when combined with polarization experiments, allow one to determine features of lamellar structure that are important to understanding mechanical properties of the cornea.
AB - Purpose. In investigations of polarized light propagation through cornea, the stromal lamellae can be considered as a stack of birefringent plates. Theory shows that such a stack is optically equivalent to two optical elements in series - a polarization rotator followed by a single birefringent plate.1 Previous experimental investigations of corneal birefringence have not recognized the rotator component. The purpose of this study was to confirm the existence of the rotator component and measure its strength. Methods. Cross-polarized transmission (I+ transmission) was measured in perfused eye bank and freshly excised rabbit corneas as the incident polarization direction, θ, was rotated through 360°. After locating θmin, the angle at which I+ transmission is minimum, the incident polarization and analyzer directions were systematically varied from their crossed configuration in the neighborhood of θmin to locate the settings that produced the absolute minimum transmission. The angular deviation of these settings from 90°, ω, is the rotation induced by the rotator component. Results. The existence of a polarization rotator component was confirmed in both human and rabbit cornea. In human ω varied between -2.0 and +2.4° (n=5) and in rabbit ω varied between -1.6 and -0.1° (n=6). As predicted in Reference 1, the percentage difference between I+min and the absolute minimum transmission is directly proportional to sin2 ω (R=0.99 for both human and rabbit). Conclusions. These results provide further confirmation of the validity of the modeling methods introduced in Ref. 1. Such methods, when combined with polarization experiments, allow one to determine features of lamellar structure that are important to understanding mechanical properties of the cornea.
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UR - http://www.scopus.com/inward/citedby.url?scp=4244173469&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:4244173469
VL - 37
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
SN - 0146-0404
IS - 3
ER -