| The rotational stability of IOL after cataract surgery is not well documented compared to tilting or decentration of IOL. For toric IOL if there is continual rotation of the implant with capsular contraction, the orientation of the astigmatic correction would be unstable and thus not clinically useful. Thus, in addition to proper surgical alignment, early and late rotational stability of toric IOLs is important. The aim is to compare the postoperative rotational stability of IOL with plate-haptic and loop-haptic,C-loop haptic and Z-loop haptic, acrylic and PMMA, So as to ascertain the optimal design and material appropriate for toric IOL.
PARTICIPANTS:
1.Patients with cataract as the only ocular disease were randomly implanted with different types of IOLs.
2.In all cases, continuous curvilinear capsulorhexis and phacoemusification were performed.
3.The cases having tears or rupture of capsule were excluded.
4.These eyes were selected on the basis of demonstrating adequate dilation of pubic following surgery, such that the point of haptic to optic insertion could be visualized with the slit-lamp biomicroscopy.
METHOD:
Patients with cataract as the only ocular disease were randomly implanted with different implants after uncomplicated phacoemulsification. Postoperative IOL position was documented using digital retroillumination images at 1 day ,2 weeks ,4 weeks after surgery. The image of the first day was determined as the baseline position of the IOL. The images were analyzed with program Adobe Photoshop and the degree of rotation was calculated.
Results:
1.2 (13.3%) of 15 of plate haptic IOLs underwent early rotational degree over 10 compared to 3 (18.8%) of 16 loop haptics. The mean rotation was 7.8 degrees for plate haptics compared to 2.9 degrees for loop haptics
2.In the Z haptic group the mean rotation was 6.7degrees ,with 5.2 degrees in the Z haptics. There was no significant difference. But, the range of IOL rotation of the C-loop haptics was broader.
3.On the first week after surgery, 3 out of 22 eyes with acrylic IOL(13.6%) showed IOL rotation over 5 degrees and two showed IOL rotation over 10 degrees , while 2 out of 8 eyes (25%) showed IOL rotation over 5 degrees and two of them showed the rotation over 10 degrees with PMMA IOL. In the group showing IOL rotation over 5 degrees, the mean rotation degree was 6.4with acrylic IOL, while PMMA IOL showed 8.9 degrees.
Conclusion:
Plate haptic IOLs show greater rotational stability than loop haptics ,but, severe rotation are more likely with the plate-haptic IOLs. IOLs with Z haptics showe greater rotational stability than C-loop haptics,. Acrylic IOLs have better performance in preventing IOL rotation than PMMA IOLs. So we can have the appropiate material and design for the toric IOL.
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