Does Cataract Surgery Reduce Eye Pressure (Intraocular Pressure)?
Cataract Surgery is a procedure that was developed with the primary goal of removing cataracts from the eye. This prevents the loss of vision associated with the development of cataracts; however, you may have heard that Cataract Surgery can also be useful for reducing eye pressure (intraocular pressure).
Increases in eye pressure – also known as Ocular Hypertension – are caused by a dysfunction in the eye’s drainage system. In normal circumstances, fluids enter the eye to provide nourishment and maintain the eye’s shape. However, when the eye’s drainage system is not working effectively, this fluid can build up, leading to an increase in intraocular pressure.
A blockage in the drainage channels of the eye or overproduction of aqueous humour (the clear fluid inside the eye) are the main causes of increased eye pressure. However, some eye conditions, as well as injury to the eye, and some medications (such as steroids) can also cause ocular hypertension.
Increased eye pressure can often lead to the development of glaucoma. In fact, it is estimated that around 10% of people with untreated ocular hypertension develop primary open angle glaucoma in five years.
Glaucoma can cause irreversible damage to the optic nerve if left untreated, leading to gradual vision loss. It is, therefore, vital that patients with ocular hypertension have regular examinations to prevent the development of glaucoma.
Eye Pressure and Cataract Surgery
While traditional glaucoma surgeries such as trabeculectomy and tube shunts are effective at lowering intraocular pressure, these procedures can carry significant risks. Furthermore, glaucoma filtering procedures and some glaucoma medications may increase the risk of cataract formation.
As glaucoma and cataracts are common comorbidities, the effects of Cataract Surgery on eye pressure is an important consideration. There is some evidence that Cataract Surgery can reduce intraocular pressure (IOP) and even decrease the progression of glaucoma.
In the past, it has been common opinion that Cataract Surgery lowers IOP in open angle glaucoma only slightly and temporarily; however, current evidence suggests that this reduction may be greater and more sustained than previously thought. But how does this work?
What is Cataract Surgery?
Cataract surgery is a routine, low-risk procedure that is performed around 400,000 times per year in England alone. It is the only effective solution for the treatment of cataracts – a condition which affects around 42% of people aged over 75-79 in the UK.
In cataract surgery, a laser or blade is used to create a small incision on the surface of the eye. Through this incision, a small ultrasound probe is used to break up the cataract and the natural lens is removed to be replaced with an artificial intraocular lens (IOL). In some cases, premium IOLs may be used to correct existing refractive errors. However, only monofocal lenses are used in NHS Cataract Surgery.
How could Cataract Surgery reduce Eye Pressure?
The exact reasons for the potential decrease in intraocular pressure following Cataract Surgery remain uncertain. However, the facility of fluid outflow is known to increase following the procedure.
The method of cataract extraction may also influence the significance of decreases in eye pressure. For example, phaco emulsification seems to lower intraocular pressure more than manual extra capsular cataract extraction.
Long-term studies have demonstrated a drop in eye pressure in open angle glaucoma patients and non-glaucoma patients with 75-85% of patients maintaining reduced eye pressure at five years.
Overall, more research is needed to fully understand the significance of intraocular pressure reductions following Cataract Surgery. Nonetheless, Cataract Surgery is usually a safe and effective procedure for patients with heightened eye pressure.
At London Vision Clinic, we evaluate the suitability of every patient on a case-by-case basis. Our rigorous screening process allows us to offer only the most appropriate treatments and ensure the best possible outcomes.