Cataract and cornea - ophthalmica.gr file Scars • PTK • Trypan blue 0.01%. • Work at the...
Transcript of Cataract and cornea - ophthalmica.gr file Scars • PTK • Trypan blue 0.01%. • Work at the...
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Cataract and cornea
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Miltos O. Balidis PhD, FEBOphth,ICOphth
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CATARACT and–Stromal opacities–Keratoplasty–Keratoconus–Endothelial pathology
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Scars• PTK• Trypan blue 0.01%.• Work at the transparent side of cornea
– Mydriasis (>7)– Hooks? Malyugin ring– Sphincterotomies
• Paraxial illumination– Endoillumination– Stereo coaxial illumination OPMI
LUMERA 700
• Nishimura A, Kobayashi A, Segawa Y, Sugiyama K. Endoillumination-assisted cataract surgery in a patient with corneal opacity. J Cataract Refract Surg. 200;29(12):2277-2280
• .www.eyetube.net/video/cataractremoval-with-lumera-700-in-corneal-opacity-case
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Combined Keratoplasty and Cataract
• Combined– Biometry
• Ave Keratometry– Rejection
• 14-31%– PC Rupture
• Vitreous– Visability
• Paraxial illumination• Small incision Phaco• ECCE IOL
– ‘Open sky’• EXPULSIVE
• 2 stages– Biometry
– Astigmatic correction• Toric IOL
– ECR
– 2 Operations
• Inflammation, rejection
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Cataract and Fuch’s• Average endothelial cell loss 8%-10% after
phacoemulsification• Viscoelastic of high ΜΒ / Low flow / Pulsed phaco / low
power / full chop in the bag / avoid any intracameral drug• Criteria for combined procedures
– Stromal edema, epithelial oedema– CCT ≥640 (20% PKP for PBK)– PBK in the other eye
• Seitzman GD, Gottsch, JD, Stark WJ. Cataract Surgery in Patients with Fuchs’ Corneal Dystrophy. Ophthalmol. 2005;112:441-446• Price FW, Price MO. Descemet’s stripping with endothelial keratoplasty in 200 eyes: Early challenges and technique to enhance• donor adherence. J. Cataract Refract Surg 2006; 32: 411-418
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Cataract and KeratoconusDiopters \procedures
0-0,75 0,75-1,5 1,5-2 2-3 >3
LTK
LRI
OCI
CCL/PRK
Toric IOL
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Patient or method selection error• Combined procedure (keratoplasty, cataract extraction and IOL
implantation) ?• Advanced keratoconus , high surface irregularity index• Central corneal opacities .
• Miscalculation may result in low-power IOL and extreme postop hyperopia
• Pre op aim for myopia.• If high plus scleral lens required postoperatively, they have greater
lens mass and reduced optic diameter• IOL exchange
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Biometry error • Total corneal power calculation
• Standard correction factor (applied to the anterior radius of corneal curvature)
• Corneal refractive index of 1.3375• Refractive effect of posterior corneal surface
• Visual axis crosses the steepest portion of the cornea• Keratoconus cone apex (typically displaced downwards and temporally).
• Accurate K’s impossible
• High anterior surface irregularity• Low Sim K repeatability (tear film abnormalities)
• Deep ACD than in the normal eye• Influence the position of the IOL relative to the central cornea.• SRK-T based on data obtained from linear regression, without incorporating
the value for the ACD.
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• Mild and moderate keratoconus predictability is relatively good (<55d).
• The use of measured K’s with a target of low myopia results in a low mean BPE*
• In advanced keratoconus there can be an unacceptably large hyperopic error BPE.
• High K’s of advanced keratoconus will result in low-power or negative-power IOL
• Standard K value should be considered• *biometry prediction error BPE
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Cataract surgery in difficult corneas
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Mr Bruce AllanMr Vincenzo MaurinoDr Miltos Balidis
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