Rotational malposition during laser in situ keratomileusis

Swami, Anil; Steinert, Roger F.; Osborne, Winifred E.; White, April

doi:10.1016/s0002-9394(01)01401-5

Cited by 115 publications

(85 citation statements)

References 5 publications

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“…Additionally, faster measurements would lead to less corneal dryness and increase the yield of measurements. For custom treatments this becomes a necessity, particularly since rotational malposition can be high (15) . One limitation of this study is that the follow-up was done at 3 months postoperatively.…”

Section: Discussionmentioning

confidence: 99%

Static cyclotorsion measurements using the Schwind Amaris laser

Fahd¹,

Jabbour²,

Fahed³

2014

Arquivos Brasileiros De Oftalmologia

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Section: Discussionmentioning

confidence: 99%

Static cyclotorsion measurements using the Schwind Amaris laser

Fahd¹,

Jabbour²,

Fahed³

2014

Arquivos Brasileiros De Oftalmologia

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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%

“…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%

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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“…Postural changes, such as moving from an upright to a supine position, can induce a mean ocular cyclotorsional effect of 0.4 to 4.2 degrees (range 0 to 16 degrees), [8][9][10][11][12] and this effect can be cyclotorsional or excylcotorsional. 8 However, keratometry is typically recorded with the patient upright, whereas ocular surgery is performed with the patient supine.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

“…8 However, keratometry is typically recorded with the patient upright, whereas ocular surgery is performed with the patient supine. As a consequence, it has been recommended that preoperative corneal markings of the 0-to 180 degree-meridian using specifically designed instruments should be made with the patient upright and that the markings should then be aligned with the 0-to 80-degree meridian of a fixation ring with the patient supine, from which the meridian of the toric IOL to be implanted is marked with a meridian marker.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%