Cyclotorsional eye motion occurring between wavefront measurement and refractive surgery

Chernyak, Dimitri

doi:10.1016/j.jcrs.2003.08.022

Cited by 121 publications

(73 citation statements)

References 8 publications

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“…[2][3][4] The stability of fixation on the horizontal and vertical plane significantly worsens through increased amounts of blur, 8 and during surface ablation the blurring of the fixation target can increase horizontal and vertical eye movements. To our knowledge, this is the first study that addresses the question of dynamic changes of eye torsion during a simulated surface ablation.…”

Section: Discussionmentioning

confidence: 99%

“…To our knowledge, this is the first study that addresses the question of dynamic changes of eye torsion during a simulated surface ablation. Recent papers in fact reported on the difference of eye position during actual refractive surgery 4 or concentrated on dynamic differences of cyclorotation in the upright vs supine position. 8 Our experiments demonstrate not only that the z eye position changes from the sitting to the supine position but also that the dynamic cyclotorsions are significantly higher in the supine position.…”

Section: Discussionmentioning

confidence: 99%

“…Chernyak 4 reported that 56% of the eyes experienced more than 21 of cyclorotation between the Wavescan measurement and the laser surgery and that 22% of eyes experienced more than 51 of cyclorotation.…”

Section: Discussionmentioning

confidence: 99%

“…The theoretical importance of torsional misalignments can be understood if we consider that a 101 alignment error results in a 30% astigmatic, 50% trefoil and 65% tetrafoil undercorrection. 1 It has been previously reported that eye orientation significantly changes when moving from an upright to a supine position [2][3][4] and it has been postulated that this might cause errors in astigmatic correction. Relatively little is known about dynamic torsional eye movements, although torsional eye movements during fixation are believed to be significantly higher than orthogonal eye movements.…”

Section: Introductionmentioning

confidence: 99%

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Cyclotorsional eye movements during a simulated PRK procedure

Fea

Sciandra

Annetta

et al. 2005

Eye

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Purpose Eye alignment is a serious concern when performing corneal surface ablation. Although several excimer lasers monitor horizontal and vertical movements, little is known about the potential impact of cyclotorsional movements. Dynamic cyclotorsions have been measured on 10 emmetropic subjects during a simulated PRK treatment. Methods Cyclotorsional eye movements were measured using a 3D videoculographic system (SMI) in 10 emmetropic subjects in upright and supine position. The subjects were wearing an eyelid speculum and were asked to fixate on a 11 red spot. The fixation target was either in focus or optically degraded by electronic filters. Data were collected at the University Eye Clinic, Torino, Italy, and the different setting measurements were compared using Student's t-test for paired data. Results Cyclotorsions were significantly higher when subjects were fixating an optically degraded stimulus (upright: P ¼ 0.04; supine: P ¼ 0.0002). The cyclotorsional movements ranged from À13 to 171. A significant difference in eye orientation was present when changing from the upright to the supine position (P ¼ 0.03). Even when correcting for this positional error, significantly higher cyclotorsional movements were detected in the supine position (in focus: P ¼ 0.0043; optically degraded: P ¼ 0.0008). The torsional range was from À14.85 to 14.551. Conclusions The high range of cyclotorsional eye movements during a simulated PRK procedure suggests that 3D tracking could improve surface ablation results when treating high astigmatism or when wavefront guided.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cyclotorsional eye movements during a simulated PRK procedure

Fea

Sciandra

Annetta

et al. 2005

Eye

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show abstract

“…However, centration and compensation for cyclotorsion are crucial in these cases. Many patients were noted to have a cyclotorsion of their eyes when shifting from erect to supine position, with one study reporting as much as 96% of eyes having cyclotorsion (2) and a different study reporting an amount as high as 9.5°( 3) . Compensation for the cyclotorsion is particularly important in irregular corneas undergoing topography-guided ablation, in eyes with a significant (4,5) .…”

Section: Introductionmentioning

confidence: 99%