As ophthalmologists, we know the most about cataracts and the potential benefit to our patients of any planned cataract surgery. But to our patients, who don’t have so many years of specialized medical training, the concept of cataract surgery is sometimes not well understood. Before cataract surgery we must use an informed consent process to educate our patients, explain to them the likely outcome of the surgery, describe potential risks, and help them make an appropriate decision.
The informed consent is a process that helps a patient understand the risks, alternatives, benefits, and indications for cataract surgery. It involves multiple aspects such as the discussion with the patient, the explanation of the procedure, and the signing of a written consent form. From the patient’s perspective, there can be some fear or trepidation about the cataract surgical procedure because of the many unknowns: Will cataract surgery hurt? What are the risks? Will I be able to see right away? How long will the lens implant last? Will I be awake? What if I move during surgery? What if I blink during surgery? Will you ever need to change the lens implant? Will there be stitches placed in the eye? Will I still need glasses after cataract surgery?
Concurrent ocular conditions and co-morbidities
Cataract surgery will correct the cataract by replacing the opaque crystalline lens with a new IOL, and we can even use the surgery to address concurrent refractive conditions. We can achieve specific refractive results, such as correcting pre-existing axial myopia or hyperopia by adjusting the spherical IOL power. Even corneal astigmatism can be addressed by virtue of how we construct the phaco incision, the placement of additional refractive incisions, or insertion of a specialty toric IOL. But co-morbidities are typically not correctable simply by performing cataract surgery.
Patients with glaucoma may achieve a lowering of the intra-ocular pressure when cataract surgery is performed, but this may not be sufficient enough to halt progression of glaucomatous nerve damage. And certainly, any pre-existing visual field defects from glaucoma will not be addressed by the cataract surgery. Retinal disease, such as macular degeneration or diabetic retinopathy, will limit the post-operative visual results from cataract surgery and these retinal conditions may even worsen after surgery.
Attributing the level of visual impairment to cataracts
When we examine and eye and diagnose cataracts, it’s important to determine an approximate level of visual function or acuity that is attributable to the lens opacities. A patient with moderate nuclear sclerotic cataracts, which would be expected to reduce the best corrected vision to about the 20/50 level, may present to us with 20/200 vision. This means that there are likely to be other factors which are affecting the vision, such as macular degeneration or a corneal scar. Patients must understand that pre-existing ocular conditions may limit their vision and that the cataract surgery may only partially address their visual needs. These co-morbidities may be present at any point in the visual system, from corneal abnormalities to central nervous system lesions, and everywhere in between. Patients should be explained that their vision can be only partially improved with cataract surgery and that they should have more reserved expectations with regards to visual recovery. Even in cases where the patient has an otherwise normal eye exam, we need to emphasize that the man-made IOL will not have the same optical performance of a young, crystalline lens.
Some patients may present with conditions that increase the risks of cataract surgery and these, too, should be explained to the patient. A patient with pseudoexfoliation syndrome may be prone to zonular weakness during surgery which could result in IOL decentration. A patient with prior keratorefractive surgery has a higher risk of ametropia due to challenges with IOL power determination. A patient with Fuchs’ endothelial dystrophy is at higher risk for corneal decompensation from the cataract surgery.
It is important to tailor the informed consent to each patient, noting the particular challenges and risks involved and the anticipated visual outcome. By addressing these issues and educating patients before planning any surgery, they become prepared and able to make appropriate decisions. Remember that cataract surgery will affect the way that cataract patients see the world, every waking moment, for the rest of their lives. This is one of the most important surgical procedures of their lives and we want to ensure that they will achieve excellent visual results.