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Cataract and cornea

ATHENS 2017

Miltos O. Balidis PhD, FEBOphth,ICOphth

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CATARACT and–Stromal opacities–Keratoplasty–Keratoconus–Endothelial pathology

ATHENS 2017

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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

ATHENS 2017

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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

ATHENS 2017

Mr Bruce AllanMr Vincenzo MaurinoDr Miltos Balidis

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