Pseudophakia

Pseudophakia is the state of having an intraocular lens implant after cataract or refractive lens surgery. It is the most common reason for a prosthetic implant in the body.

• Lens types: monofocal (single focus), toric (astigmatism), extended depth of focus, multifocal, and accommodating lenses; materials include hydrophobic acrylic, hydrophilic acrylic, silicone and polymethylmethacrylate.
• Position: in-the-bag (preferred), ciliary sulcus, scleral fixated, iris fixated, or anterior chamber.
• Postoperative problems are common enough to form their own clinical domain, and often present years after surgery.

• Early (days to weeks): inflammation, raised pressure, corneal oedema, wound leak, endophthalmitis.
• Intermediate and late:
  • Pseudophakic cystoid macular oedema (Irvine-Gass syndrome): blurred, distorted central vision 4 to 12 weeks after surgery.
  • Posterior capsule opacification: glare and blurred vision months to years after surgery.
  • Dysphotopsia: positive (haloes, arcs, flare) or negative (a temporal dark crescent), reported by 10 to 20 percent early, with persistence in 1 to 3 percent.
  • Intraocular lens decentration, tilt, dislocation (in the bag or out of the bag), pupillary capture, or iris chafing causing uveitis-glaucoma-hyphaema syndrome.
  • Pseudophakic bullous keratopathy, pseudophakic retinal detachment (about 0.5 to 1 percent over years; higher in men, axial myopia, and following posterior capsule rupture).
  • Opacification of the lens optic (calcification of hydrophilic acrylic lenses, glistenings of hydrophobic lenses).
  • Residual refractive error (refractive surprise), unwanted astigmatism, and anisometropia.

• Visual acuity, refraction, slit lamp examination of lens position, capsule, haze and corneal status; keratometry and biometry audit for refractive surprise.
• Intraocular pressure; dilated fundus examination; macular optical coherence tomography (cystoid oedema); fluorescein angiography in unclear cases.
• Anterior segment OCT or ultrasound biomicroscopy for lens position and haptic location.
• Aberrometry and glare tests for dysphotopsia.

• Pseudophakic cystoid macular oedema: topical NSAID (nepafenac 0.1 percent three times daily or bromfenac 0.09 percent daily) with topical steroid (prednisolone acetate 1 percent four times daily or difluprednate 0.05 percent four times daily) for 6 to 12 weeks; if resistant, sub-Tenon triamcinolone 40 mg, intravitreal triamcinolone 2 mg or dexamethasone implant 0.7 mg, and oral acetazolamide 250 mg twice daily.
• Posterior capsule opacification: Nd:YAG laser capsulotomy.
• Dysphotopsia: reassurance and neuroadaptation (most improve over 6 to 12 months), pilocarpine 1 percent for negative dysphotopsia in selected cases, and, if disabling, reverse optic capture or sulcus piggyback lens, or lens exchange.
• Refractive surprise: spectacles or contact lenses, laser vision correction (photorefractive keratectomy or LASIK, off label for large errors), piggyback supplementary sulcus lens, or intraocular lens exchange when the error is large (generally more than 2 dioptres).
• Lens malposition: repositioning with sutures (scleral fixation or iris fixation), or exchange, or surgical removal with replacement; opacified hydrophilic lenses need exchange.
• Uveitis-glaucoma-hyphaema syndrome: topical steroids, cycloplegics, aqueous suppressants; reposition or exchange the lens if persistent.
• Retinal detachment: urgent vitrectomy or scleral buckle.
• Long term follow up for pressure, macula and capsule.