Cataract surgery is one of the most frequently performed and successful procedures worldwide, restoring vision for millions. While generally safe and routine, it is an invasive medical procedure, and not every individual is an ideal candidate. Certain temporary conditions, chronic diseases, or systemic health issues can significantly increase the risk of complications or make a successful visual outcome unlikely. Identifying these scenarios is necessary for patient safety and to ensure the maximum benefit from the operation.
Temporary Conditions Requiring Delay
Surgery must be postponed if a patient has an active infection, either in the eye or elsewhere in the body. Operating on an eye with active conjunctivitis, blepharitis, or a corneal abrasion dramatically increases the risk of a severe post-operative infection, known as endophthalmitis. An active systemic illness, such as influenza or a severe respiratory cold, can also compromise a patient’s stability during the procedure and complicate recovery.
Acute medical instability, such as a severe spike in blood pressure, also necessitates a delay, particularly on the day of the procedure. Uncontrolled hypertension can lead to complications like bleeding during surgery. It is safer to defer the operation until the patient’s condition is stabilized with medication. Once these temporary ocular or systemic issues are successfully treated, the procedure can typically be rescheduled safely.
Severe Pre-Existing Eye Diseases
The success of cataract surgery depends on the overall health of the eye, particularly the structures behind the lens. Patients with advanced age-related macular degeneration (AMD) or severe diabetic retinopathy may not experience significant visual improvement. This is because the underlying vision loss is not primarily due to the cloudy lens, meaning the risk of surgery may outweigh the minimal expected benefit.
Severe, uncontrolled glaucoma is a serious concern, as the operation can sometimes temporarily increase intraocular pressure, potentially worsening optic nerve damage. Corneal diseases, such as advanced Fuchs’ dystrophy, also complicate the procedure and recovery because the cornea is already compromised. The stress of surgery can lead to corneal swelling and decompensation, resulting in permanently blurred vision. Severe amblyopia, or “lazy eye,” means the visual potential is inherently low, and surgery may not restore functional vision.
Unmanageable General Health Risks
Cataract surgery is generally performed using local anesthesia and sedation. However, certain chronic, unstable systemic conditions pose a serious threat to patient safety. Individuals with severe, poorly managed cardiovascular disease, such as unstable angina or recent heart failure, face a higher risk due to the stress of the procedure and the effects of sedation.
Poorly controlled Type 1 or Type 2 diabetes is a major concern. High blood sugar levels impair the body’s ability to heal and significantly increase the risk of post-operative infection. Uncontrolled diabetes can also worsen pre-existing diabetic retinopathy after surgery. Conditions causing involuntary tremors, such as advanced Parkinson’s disease, can make the delicate microsurgery impossible, as the patient cannot remain still.
Factors Related to Patient Compliance and Expectations
A successful outcome relies heavily on the patient’s ability to follow complex post-operative instructions, including the precise application of eye drops. Patients with significant cognitive impairment, such as advanced dementia, cannot reliably adhere to this regimen and are at high risk for infection and poor healing. The inability to lie flat and still for the duration of the surgery is also a contraindication.
Patient expectations also play a large role in determining satisfaction. If patients expect perfect 20/20 vision despite coexisting eye conditions like AMD, they may be dissatisfied even if the surgery is technically successful. Unrealistic expectations must be managed pre-operatively to ensure the patient understands the limitations of the procedure based on their health profile.