Visually significant posterior capsular opacification (PCO), also known as after cataract, is the most common complication of cataract surgery, occurring in 20-25% of patients. It is caused by the proliferation of lens epithelial cells remaining in the capsular bag after surgery. Symptoms include blurry vision, glare, and sometimes double vision. Treatment involves using a Nd:YAG laser to create an opening in the posterior capsule. This procedure is called a posterior capsulotomy and effectively treats PCO symptoms.

2. • Visually significant PCO, also known as 'after
cataract', is the most common late complication
of uncomplicated cataract surgery, occurring in
20-25% of patients.
• It is caused by the proliferation of lens epithelial
cells that have remained within the capsular bag
following cataract extraction. The incidence of
PCO is reduced when the capsulorhexis opening
is in complete contact with the anterior surface of
the IOL.

3. • PMMA “ polymethylmethacrylate “ (and probably
to a lesser extent hydro-gel) IOLs are particularly
prone to PCO. Implant design is more important
than material.

4. • Symptoms: include persistent slowly worsening
blurring, glare and sometimes monocular
diplopia.
• Visual Acuity is variably reduced, though
dysfunction may be more marked on contrast
sensitivity testing.

5. • Typically include more than one pattern of opacification.
• 1) Vacuolated (pearl-type) PCO consists of proliferating
swollen lens epithelial cells, similar to the bladder (Wedl)
cells seen in posterior subcapsular cataract . They are
commonly termed ‘Elschnig pearls’.
• particularly when grouped into clusters at the edge of a
capsulotomy, though strictly Hirschberg-Elschnig pearls
refers to globular or grape-like collections of swollen cells
seen following traumatic or surgical anterior capsular
rupture.

7. Vacuolated or pearl-type on retroillumination.

8. Elschnig pearl formation (arrow) on edge of
capsulotomy.

9. • 2) Fibrosis-type PCO
is thought to be due to
Fibroblastic metaplasia of
Epithelial cells, which
develop contractile
qualities.

10. Slit-lamp appearance of fibrotic capsule.

11. • 3) A Soemmering ring is a whitish annular or
doughnut-shaped proliferation of residual cells
that classically formed almost in the periphery of
the capsular bag following older methods of
cataract surgery, but is uncommon now. It may
form at the edge of a capsulorhexis or
capsulotomy.

12. Soemmering ring following congenital cataract surgery.

13. • Treatment involves the creation of an opening in
the posterior capsule using a Nd:YAG laser
(termed a posterior capsulotomy).
TiP From Kanski
Posterior capsular thickening is the
commonest cause of late visual deterioration
after small incisional cataract surgery and is
easily treated with a Nd:YAG laser.

14. Appearance following laser capsulotomy.

15. • Indications: The presence of visual symptoms is the main
indication (reduced VA and glare). Less commonly, capsulotomy
is performed to improve an inadequate fundus view impairing
assessment and treatment of posterior segment pathology.
• Technique: Safe and successful laser capsulotomy involves
accurate focusing and use of the minimum energy required. Laser
power is initially set at 1 mJ/pulse and may be increased if
necessary. A series of punctures is applied in a cruciate or
circumferential pattern using single-pulse shots. The opening
should equate approximately to the size of the physiologically
dilated pupil under scotopic conditions - this should average
around 4-5 mm in the pseudophakic eye. A larger capsulotomy
may be necessary if glare persists, or for retinal examination or
treatment, but the capsulotomy should not extend beyond the
edge of the optic in case vitreous prolapses around its edge. It
may be prudent to adopt a higher threshold for treatment, and
minimizing its extent, in eyes at risk of retinal detachment (e.g.
high myopia), CMO “ Cystoid Macular Oedema “ (e.g. history of
uveitis) or lens displacement (e.g. pseudoexfoliation). Some
research suggests that the total energy applied should be less
than 80 mJ in order to reduce the risk of a significant IOP spike.

16. • Complications: include pitting of the IOL that is
usually visually inconsequential. The IOP may
rise, particularly in patients with glaucoma, but is
typically mild and transient. A retinal tear or
detachment may follow the treatment and myopic
individuals should be warned to return if they
develop symptoms compatible with a posterior
vitreous detachment (PVD). CMO may occur, but
is less common when the capsulotomy is
delayed for 6 months or more after cataract
surgery. IOL subluxation or dislocation is rare.

17. Laser pitting of an intraocular lens.