Cataract Surgery: A Brief Introduction
Cataracts are the leading cause of reversible blindness in the world. Cataract surgery involves removal of the cataract and replacement with an intraocular lens. As many as 95% of patients will have an improved visual acuity (1), often accompanied by significant improvement in their quality of life. It does however have complications which patients should be made aware of prior to surgery and these are what will be covered in this article.
The aim of this article is to give a concise, yet relevant overview of the key complications that should be considered when reviewing patients post-operatively.
- Intra-operative complications
- Early post-operative complications (i.e within 6 weeks of surgery)
- Late post-operative complications
Posterior capsule rupture:
- The capsule houses the implanted intraocular lens. It also acts as a barrier between the anterior segment and the vitreous of the eye.
- Rupture of this capsule can occur at any stage of surgery, especially during phacoemulsification of the lens.
- Management: It is usually managed by the surgeon during the operation and can lead to retained lens fragments and oedema in the cornea/ macula.
- Patients are at an increased risk of endophthalmitis and retinal detachments if they experience this intra-operatively.
Floppy Iris syndrome:
- May be associated with the use of alpha blockers such as tamsulosin.
- It can present challenges intra-operatively as the pupil may not dilate effectively, increasing the risk of complications such as a posterior capsule rupture.
- Management: This is usually mitigated by injecting dilating agents into the anterior chamber (e.g phenylephrine 2.5%) or using hooks to mechanically stretch the pupil.
Early Post Operative Complications
Immediate post-op: Transient rise in intraocular pressure and corneal oedema
- This is a sight threatening emergency which must be reviewed and treated promptly.
- It is a severe inflammation of the intraocular fluids including the vitreous +/- aqueous humour due to infection, most commonly as a result of staphylococcal epidermidis, accounting for 80% of these infections (1).
- Patients tend to present within the first week after surgery with an acute red and painful eye along with reduced visual acuity.
- Examination findings usually include a hypopyon (pus in the anterior chamber) and a poor view of the posterior chamber due to vitritis (inflammation of the vitreous).
- Management: The immediate management is a “tap and inject”, where samples of aqueous humour and vitreous are taken (“tap”), which is then followed by injection of antibiotics into the vitreous cavity (“inject”). Occasionally, patients may require a procedure called pars plana vitrectomy, where the vitreous is removed to clear off the infective debris. This is usually for patients who are not improving/deteriorating despite standard treatment.
Cystoid macular oedema:
- When fluid develops within the macula due to disruption of the blood-retinal barrier from inflammation.
- It usually occurs within 6 weeks post-operatively.
- Patients typically present with a reduction in visual acuity.
- Management: It tends to respond very well to a combination of topical NSAIDs and steroids, however,occasionally an injection of steroids into the periorbital space or injection of a slow-release dexamethasone implant (e.g Ozurdex) into the vitreous cavity is required if the oedema does not respond to prolonged topical treatment.
- This is when the implanted intraocular lens moves out of position and “dislocates”.
- This can occur anytime after cataract surgery and can present as phacodonesis (when the IOL moves with eye movement), subluxation or complete dislocation.
- Patients will typically present with a change in vision including diplopia, glare or pain in the affected eye.
- Management: This depends upon the extent to which the lens is out of place. This ranges from observation +/- optimisation of refraction with regular follow-up to re-positioning of the intraocular lens.
Late Post Operative Complications
Posterior capsule opacification:
- This is the most common complication after cataract surgery.
- This occurs when residual lens cells migrate to the posterior capsule and proliferate, causing clouding of the lens and leading to what is often referred to as a “secondary cataract”.
- Management: This is typically treated with a procedure known as a YAG laser capsulotomy. This quick procedure involves using a laser to make a small hole in the posterior capsule which will allow light to pass through unobstructed, thereby increasing vision. This procedure does not come without its own complications, including retinal detachment, cystoid macular oedema or damage to the IOL itself but the risks are relatively small (2).
Retinal tear/ detachment:
- These patients will present with new flashing lights and floaters in their vision, sometimes accompanied by reduced visual acuity/ vision loss. Visual fields may also be affected.
- Management: Retinal tears are treated by forming a laser barrier to seal the tear (laser retinopexy) or using a freezing probe applied through the conjunctiva at the site of the tear to promote chorioretinal (choroid and retina) adhesion (retinal cryopexy).
- There are various treatment options for retinal detachments such as pars plana vitrectomy, pneumatic retinopexy and scleral buckling.
Other Visual Complaints Patients May Describe (Dysphotopsias)
Positive: haloes/ patterns around lights
Negative symptoms: shadows or dark areas
If these symptoms are very bothersome for patients, treatments can include repositioning of the IOL/ YAG laser capsulotomy but these do not come without the risk of complications (1).
- Milner, M. et al. (2022) Cataract Surgery, StatPearls. Available at : https://pubmed.ncbi.nlm.nih.gov/32644679/(Accessed: November 21, 2022)
- Miller, K. et al. (2022) Cataract surgery complications, EyeWiki. Available at: https://eyewiki.aao.org/Cataract_Surgery_Complications (Accessed: November 22, 2022).
Written by Dr Matthew Mo (FY2) & reviewed by Dr Alex Yeong (ST7 Ophthalmology)
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