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TEI GRAND ROUND. REFRACTIVE SURGERY: BIOPTICS AND CORRECTION OF DECENTERED ABLATIONS 06 Jul 05. Bioptics for myopia – Case 1. Case Summary. 23/Chinese/Female No PMHx Severe Myopia Pre Op. Case Summary. Listed for AC PIOL for Myopia Rt IOL – 28 Jun 04 Lt IOL – 05 Jul 04

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tei grand round
TEI GRAND ROUND

REFRACTIVE SURGERY:

BIOPTICS AND CORRECTION OF DECENTERED ABLATIONS

06 Jul 05

case summary
Case Summary
  • 23/Chinese/Female
  • No PMHx
  • Severe Myopia
  • Pre Op
case summary4
Case Summary
  • Listed for AC PIOL for Myopia
    • Rt IOL – 28 Jun 04
    • Lt IOL – 05 Jul 04
  • Post IOL Op (3.5 mths)
case summary5
Case Summary
  • Pre op suitability testing for enhancement via LASIK
    • ECC : OD 2700; OS 2500
    • Contrast sensitivity: N (F.A.C.T)
    • Orbscan: OD 554 um; OS 555um
  • 19 Nov 04 Intralase & LASIK done for Rt eye (-1.70DS/-2.25DC/40)
  • Intralase.MPG
  • Flap Lifting.MPG
case summary6
Case Summary
  • Post LASIK (2 months)
case summary8
Case Summary
  • Ms N
  • 24 year old / Chinese Malaysian / F
  • Contact lens intolerant with GPC / Peripheral vascularization
  • poor LASIK candidate (OD 539mm, OS 506mm)
case summary9
Case Summary
  • Lt AC PIOL with inferior AK
  • Rt AC PIOL with inferior AK
case summary10
Case Summary
  • Patient underwent Rt intralase and LASIK
bioptics
Bioptics
  • Defined as combination of 2 procedures1
    • Phakic IOL implantation followed by LASIK to correct high degrees of refractive error
    • Maximal degree of myopia or hyperopia intended to be corrected by the IOL
    • Residual refractive error corrected with LASIK after 1 – 3 mths
efficacy of piol for high myopic
Efficacy of PIOL for high myopic
  • Artisan PIOL – Benedetti et al9
    • UCVA > 20/40 - 83.8% (Myopia -6.75 to 15.5D)
    • UCVA > 20/40 - 68.0% (Myopia -16 to 23D)
    • Complications
      • Iris atrophy 11.8%
      • Lens decentration 5.4%
      • Night glare 6.4%
    • Mean Endothelial cell loss11: 0.87-3.9% (12 mths) and 0.78 - 5.4% (24 mths)
efficacy of piol for high myopic14
Efficacy of PIOL for high myopic
  • Comaparsion of PIOL positional stability– Baumeister et al10
    • AC PIOL – No Sig. Ant-post mvt
    • PC IOL – Sig mvt towards crystalline lens
    • Optical Axis Rotation
      • Nuvita – 1.9 degrees
      • Artisan – 0.6 degrees
      • ICL – 0.9 degrees
    • AC IOL (iris fixated) - Best positional stability
contraindications for piol
Contraindications for PIOL
  • Contraindications for PIOL
    • AC depth < 3mm
    • Endothelial cell counts < 2000
    • Previous lens opacities
    • Ant segment pathologies
limitations of individual modalities
Limitations of individual modalities
  • LASIK for high myopics (>-12.0D)
    • Limited corrective magnitude dependent on corneal thickness
    • Increased level of side effects secondary to increased corneal depth ablation
  • PIOL
    • IOL decentration and displacement
    • Cataract formation
    • Pupillary block glaucoma
    • Inflammatory lens precipitates
    • Anterior Chamber (Uveitis – Glaucoma – Hyphema Syndrome, Endothelial decompensation)
bioptics17
Bioptics
  • Key Advantages
    • Utilises best of both worlds
    • Increases possible range of surgical correction for myopia and hyperopia with decreased side effects
    • Good predictability with LASIK
    • Better functional vision post LASIK
  • Key Disadvantages
    • Staged - Interval between surgeries
    • 2 separate procedures hence increase surgical risk
    • Complications related to PIOL
    • Complications related to LASIK
evolution of bioptics
Evolution of Bioptics
  • Described by Roberto Zaldivar2,4,5
    • In 1988, he used AC PIOLs (Angle Fixated) alone.
    • Baikoff or Nuvita Lens.
    • Many AC PIOL related complications
evolution of bioptics19
Evolution of Bioptics
  • In 1996, Zaldivar pioneered bioptics technique. 2
    • PC instead of AC PIOL (STAAR AG ICL)
    • Combination follow on of LASIK after PC PIOLs
  • PC considered better site vs AC 4,5
    • Risk of endothelial damage minimised
    • Fewer incidences of Halos or glares
  • However, key specific disadvs were noted 4,5
    • Decentration
    • Risk of cataractogenesis & PCO formation
    • Pupillary block glaucoma
evolution of bioptics20
Evolution of Bioptics
  • Jose Guell modified the bioptics technique6
  • Termed ARS approach
      • Utilises AC PIOL but IRIS fixated
        • Artisan non-toric lens
      • LASIK flap performed before IOL implantation
      • 6mm optical zone for both procedures7
  • Key specific advantages vs PC IOL
      • Endothelial-IOL contact during microkeratome pass avoided8
      • No potential risk of PC PIOL dislocation during suction
suggested choice for each patient
Suggested choice for each Patient
  • Myopia -9.0 to -12.0D – LASIK
  • Myopia -12.0D to -15.0D – Phakic IOL implantation
  • Myopia > 15.0D – Bioptics
  • More than 50yrs or early lens opacification – Lens extraction with LASIK for residual refractive error
in the pipeline
In the pipeline
  • Toric AC PIOL lens12
      • Mean post op astigmatism – 0.56D/ Axis 31 degrees
      • 6 mnth follow up – No significant rotation observed
  • LASEK with AC PIOL13
      • Murta et al used LASEK as an alternative to LASIK
      • 32 eyes in 18 patients
      • Mean Pre Op SE -16.2D
      • Artisan AC PIOL followed by LASEK 2-3 mths later
      • 90% +1D emmetropia; 71.9% +0.5 D emmetropia
      • LASEK Cx – Epi Defect 1st POD 72%; Grd 1 haze 12.5%
      • Implications – Alternative for LASIK incompatible
  • Intralase for LASIK flap creation
references
References
  • Guell, Vazquez. Bioptics, Int Ophth Clin, Summ 2000.
  • Zaldivar, Oscherow, Ricur. The STAAR Posterior Chamber Phakic Intraocular lens. Int Ophth Clin, Summ 2000.
  • Zaldivar, Oscherow, Ricur. Implantable contact lens. In: Clear corneal lens surgery. Thorofare, NJ: SLACK, 1999.
  • Zaldivar, Davidorf, Oscherow. Combined posterior chamber phakic intraocular lens and laser in stu keratomileusis: bioptics for extreme myopia. J Refract Surg 1999.
  • Zaldivar, Davidorf, oscherow. Posterior chamber phakic intraocular lens for myopia -8 to -19 diopters. J Refract Surg 1998.
  • Guell JL. The adjustable refractive surgery concept (ARS). [Letter] J Refract Surg 1998.
  • Guell, Vazquez. ARS ( Adjustable Refractive Surgery): 6mm Artisan lens plus LASIK for correction of high myopia. AAO meeting Orlando, Oct 99.
  • Endothelial study of iris claw phakic lens: four year follow up. J Refract Surg 98.
  • Benedetti, Casamenti, Marcaccio. Correction of myopia of 7 to 24 dioptres with artisan phakic intraocular lens: 2 yr follow up. J Refract Surg 2005
  • Baumeister, Buhren, Kohnen. Position of angle supported, iris fixated and cilary sulcus implanted myopic PIOL evaluated by Scheimpflug photography
  • Pop M, Payette. Initial results of ECC after artisan lens for phakic eyes. Ophthalmology Feb 2004
  • Tehrani. Postoperative astigmatism and rotational stability after artisan toric phakic IOL implantation. J Cataaract Refract Surg Sep 2003
  • Murta et al. Artisan phakic IOL implantation followed by LASEK. 7th ESCRS Winter Refractive Surgery Meeting.
slide25
Ms T
  • 32 year old / Chinese / Malaysian / F
  • Originally bilateral high myope of approximately –16D.
  • OD conventional PRK 1 month previously in Kuala Lumpur
  • 4 days later, OS clear-lens extraction: aphakic
slide26
Refraction at presentation:
  • OD: -4.00/-1.50 x 50: 6/15
  • OS: +0.75/-1.50 x 180: 6/12
  • OD decentered ablation complicated by anterior basement membrane dystrophy with subepithelial scarring.
od post op corneal topo
OD post-op corneal topo
  • OD superior decentration of central ablation zone. Central visual axis is undercorrected with resultant lower and higher order aberrations.
  • Clinically, pt c/o starburst effect and increasing anisometropia
  • Rx? Prevention, miotics, RGP lenses
  • Enhancement, wave-front / topography guided
wavefront assessment
Wavefront assessment
  • Undilated –8.37/-1.53 x 97, pupil size 4.85
  • Dilated –7.44/2.76 x 17

(least amount of higher order aberrations)

slide30
Post-wavefront PTK correction:
  • UCVA: 6/7.5
  • Refraction: plano / -0.50: 6/6
post prk lasik decentration
Post-PRK / LASIK decentration
  • PRK centration accurate to within 1.0 mm in over 92% of cases and visual acuity is relatively preserved despite deviations from perfect centration

Topographical analysis of the centration of excimer laser photorefractive keratectomy.Cavanaugh TB, Durrie DS, Riedel SM, Hunkeler JD, Lesher MP. J Cataract Refract Surg. 1993;19 Suppl:136-43.

slide33
Centration of keratorefractive procedures from the pupil is important and influences lower / higher order aberrations.
  • Centration was measured more accurately from the pupillary center (0.40 mm) than from the corneal vertex (0.44 mm).

Centration of excimer laser photorefractive keratectomy relative to the pupil.Cavanaugh TB, Durrie DS, Riedel SM, Hunkeler JD, Lesher MP. J Cataract Refract Surg. 1993;19 Suppl:144-8.

conventional ptk for decentered ablations
Conventional PTK for decentered ablations
  • repeat PTK using technique where a circle of adherent epithelium overlying the decentered ablation served as a mask.

Retreatment of decentered excimer photorefractive keratectomy ablations.Lim-Bon-Siong R, Williams JM, Steinert RF, Pepose JS. Am J Ophthalmol. 1997 Jan;123(1):122-4. Diametral ablation--a technique to manage decentered photorefractive keratectomy for myopia.Alkara N, Genth U, Seiler T. J Refract Surg. 1999 Jul-Aug;15(4):436-40.

wave front guided lasik ptk
Wave-front guided LASIK / PTK
  • Achievement of reduction in refractive cylinder, increase in uncorrected visual acuity, and improved corneal regularity in the majority of patients with severe corneal irregularities e.g. decentered / small optical zones after LASIK or irregular astigmatism after keratoplasty / trauma. Poorer results in small irregularities e.g. central islands.

Topographically-guided laser in situ keratomileusis to treat corneal irregularities.Knorz MC, Jendritza B. Ophthalmology. 2000 Jun;107(6):1138-43. Selective zonal ablations with excimer laser for correction of irregular astigmatism induced by refractive surgery.Alio JL, Artola A, Rodriguez-Mier FA. Ophthalmology. 2000 Apr;107(4):662-73.

Early clinical experience using custom excimer laser ablations to treat irregular astigmatism. Tamayo Fernandez GE, Serrano MG. J Cataract Refract Surg. 2000 Oct;26(10):1442-50.

topography guided wave front for scarred extremely irregular corneas
Topography-guided wave-front: for scarred / extremely irregular corneas
  • combination of topographic data with computer controlled flying-spot excimer laser ablation was suitable for correcting irregular astigmatism after significant (>1mm) postmyopic PRK decentrations.

Topography-driven excimer laser for the retreatment of decentralized myopic photorefractive keratectomy.Alessio G, Boscia F, La Tegola MG, Sborgia C.Ophthalmology. 2001 Sep;108(9):1695-703.

Topographically supported customized ablation for the management of decentered laser in situ keratomileusis.Kymionis GD, Panagopoulou SI, Aslanides IM, Plainis S, Astyrakakis N, Pallikaris IG. Am J Ophthalmol. 2004 May;137(5):806-11.

Aberration-sensing and wavefront-guided laser in situ keratomileusis: management of decentered ablation.Mrochen M, Krueger RR, Bueeler M, Seiler T. J Refract Surg. 2002 Jul-Aug;18(4):418-29.

higher order aberrations
Higher-order aberrations?
  • Total and higher-order RMS aberrations decreased by 40 - 45%, after C-CAP treatment.
  • Topography-driven C-CAP method is effective in post-surgical decentration to enhance the overall quality of vision, reduce patient-perceived visual aberrations, regularize the corneal surface, and maximize BCVA.

Custom-contoured ablation pattern method for the treatment of decentered laser ablations.Lin DY, Manche EE. J Cataract Refract Surg. 2004 Aug;30(8):1675-84.