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Introduction

Posterior capsule opacification

ü   Secondary cataract

n  Long-term complication of modern cataract surgery

ü   Age dependent (low incidence in older patient)

ü   Treatment

Nd: YAG laser capsulotomy

n  create a central opening in posterior capsule)

n  Complication : damage to IOLs, cystoids macular edema, IOP increased, iris hemorrhage, corneal edema, localized endophthalmitis

n  Silicon > PMMA

n  Cost burden to health care system

ü   PCO preventive options  (Figure 2)

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Mechanisms of PCO development (Figure 3)

ü   Residual lens epithelial cells (LECs)

ü   Wound healing response induced

ü   Clinical morphological types

n  Fibrosis-type

n  Pearl-type

ü   Molecular mechanism are not completely clear

n  Cytokines & growth factors

TGF-β, FGF-2, IL-1, IL-6,

Hepatocyte growth factors, epithelial growth factors

Prevention of PCO

ü   Common complication

47.3~100% in children

high incidence, quicker onset, greater amblyogenic effect

ü   Surgical techniques

n  Vaccuming or polishing

May delay the onset, but the long-term benefit is limited.

ßàAdditional surgery time, trauma risk

n  Hydrodissection

Effective, practical, and inexpensive

ßà Nuclear dislocation into the vitreous. No practical in hypermature?

n  Sealed capsule irrigation device

Foldable suction ring, 2 separate lines (one for vacuum, one for irrigation, sent pharmacological agent without damage surrounding tissues)

àinexpensive, not add significant time

n  Capsulorrhexis with anterior vitrectomy

n  Others: capsulorrhexis size, in-the-bag fixation

ü   IOL materials and designs

n  Uveal biocompatibility / Capsular biocompatibility

n  Material

Silicone / Arylic (rigid: PMMA / foldable: hydrophobic, hydrophilic material)

Hydrophilic acrylic may support LECs

n  IOL designs

May provided mechanical barrier effect

Surface modification (polyethylene glycol, gas plasma )

Sharp edge

ü   Therapeutic agents

n  Direct injection into the anterior chamber, irrigation solution

ßà toxicity to surrounding tissue

(phenol formaldehyde resins, methotrexate, mitomycin, flurouracil….)

n  Gene therapy

Inducing therapeutic apoptosis by over expression of proapototic genes

n  Proteasome inhibitor

Conclusions