CLINICAL

  ANTERIOR

CARE FOR YOUR CATARACT PATIENTS

TAKE THE REINS AS THESE PATIENTS’ PRIMARY EYE CARE PRACTITIONER

JOSH JOHNSTON, O.D., F.A.A.O.

CATARACT SURGERY is now the No. 1 surgery performed in the United States, surpassing cesarean sections. This is, no doubt, due to the aging of baby boomers. The fact that we, as optometrists, are seeing so many of these patients before they see an ophthalmologist presents a huge opportunity for us to ensure we remain their primary eye care providers.

Here, I discuss the etiology, symptoms and clinical signs of cataracts to ensure a prompt diagnosis, I describe our role in managing these patients, and I provide a look at future IOL options.

ETIOLOGY

A cataract is the opacification of the crystalline lens. It is considered the most common cause of vision loss in patients older than age 40.

The three main types of cataract are nuclear (the most common, which affects the middle of the lens), cortical (the “shell” of the lens) and subcapsular, also called posterior capsular, (affecting the back of the lens). Nuclear cataracts typically grow slowly through years to decades, cortical cataracts grow from the outside edges toward the center of the lens, and subcapsular cataracts typically progress quickly.

The risk factors associated with cataract formation are increasing age, exposure to ultraviolet radiation from sunlight, diabetes, hypertension, obesity, smoking, high consumption of alcohol, prior eye injury or eye surgery, high myopia, hormone replacement therapy, family history and use of certain medications, such as oral steroids, which often cause subcapsular cataracts.

SYMPTOMS

Symptoms depend on the type of cataract.

• Nuclear cataract. This type of cataract alters the eye’s focusing ability and may temporarily improve near vision for tasks, such as reading. This temporary improvement is called “second sight” and is due to myopic shift — a result of the increased density of the lens.

• Cortical cataract. This causes glare and halos at night, blurred vision, decreased contrast sensitivity and depth of focus.

• Subcapsular cataract. This type of cataract causes glare and halos. Symptoms often don’t match clinical signs, as even a small subcapsular cataract can greatly affect vision. This is because this cataract forms on the central posterior portion of the lens right in the center of the visual axis.

CLINICAL SIGNS

Clinical signs also depend on the type of cataract.

• Nuclear cataract. This appears as yellow and sometimes brown.

• Cortical cataract. This has a unique wedge or spoke-like appearance.

• Subcapsular cataract. This is seen as an opacity at the back of the lens.

MANAGEMENT OPTIONS

Once you have diagnosed a cataract, your role is threefold: (1) discussing surgical/IOL options (2) conducting a complete exam and (3) comanagement.

1. Discussing IOL/surgical options. To ensure your cataract patient has a successful surgical outcome and to show you’re a crucial member of his or her eye health team, you must stay abreast of the latest in cataract surgery and IOLs. For example, in addition to modern phacoemulsification and older techniques, such as extracapsular surgery, are you aware of femtosecond laser procedures or arcuate incisions for patients who have astigmatism?

With regard to IOLs, do you know about all the monofocal, toric, accommodating and multifocal designs and their benefits and limitations? It’s imperative that you discuss the limitations of the chosen IOL, so the patient is not “surprised” and, therefore, dissatisfied with his or her vision post-surgery. (A dissatisfied patient is an unhappy one, who will likely seek care elsewhere.) An example patient script: “Jeannie, multifocal IOLs offer distance, intermediate and near vision. They split light to create two focal points, which provides good vision. In addition, they can induce some glare and halos.”

2. Conduct a comprehensive exam prior to the surgery. Prior to a patient undergoing cataract surgery, look from the front to the back of the eye for any possible conditions that can limit the patient’s visual outcome. Since this section of “Optometric Management” deals exclusively with the anterior segment of the eye, here’s some advice on assessing this portion prior to cataract surgery. Start by looking at the external ocular adnexa. Do you see any redness of the face, peri-orbital redness, rhinophyma or other classic signs of rosacea? Does gross examination of the peri-orbital area reveal lid dermatochalasis that might cause functional limitations on vision? Next, examine the lids. Demodex is often ignored and untreated and can cause symptoms, such as chronic irritation, burning and other similar dry eye symptoms, including discomfort. Also, blepharitis has been found in 59% of cataract patients. Although rare, bacteria associated with blepharitis increases the risk of post-op endophthalmitis.

How important are your co-management skills? I diagnosed this patient with retained cortex S/P cataract surgery. The retained cortex was causing chronic inflammation and iritis and also limiting the vision because the residual cortex was in the visual axis.

Now, examine the patient’s ocular surface. Dry eye disease can limit the visual outcome in cataract patients. Specifically, it has been reported to cause residual refractive errors by as much as 1.00D to 2.00D due to inaccurate pre-op calculations. For example, residual refractive error as small as 0.50D can limit the VA for patients with multifocal IOLs. These measurement errors from bad pre-op data can lead to the wrong axis placement with a toric IOL or even the wrong IOL power choice.

Finally, be aware of anterior basement membrane dystrophy, Salzmann’s nodular dystrophy, Fuchs’ corneal dystrophy, corneal scars, lagophthalmos and exposure keratitis, so you can treat prior these to the surgery if possible.

3. Comanage the patient. When referring the cataract patient for surgery, make the ophthalmologist aware that you will be comanaging the patient, so he or she keeps you in the loop regarding the procedure and needed follow-up care. You want to work with cataract surgeons who are experienced and optometric friendly. (See: “Choosing an M.D.,” http://bit.ly/1OalghV.) Further, it’s important to educate your cataract patients that you will be taking over care from the surgeon after the surgery and that you will have follow-up visits with the patient typically the first day, first week and one month after the surgery. I say to my cataract patients, “The surgeon does the surgery, and I will do everything else.”

The post-surgical complications of cataract surgery can include confusion regarding the prescribed drop regimen (O.D.s need to monitor proper post-op drop regimens, as most cataract patients are prescribed an antibiotic, a steroid, and a NSAID), acute increased IOP from retained viscoelastic, causing corneal edema and microcystic corneal bullae, a wound leak causing hypotony or infection, secondary complications, such as herpes simplex virus keratitis from topical steroid use, rebound iritis, posterior capsular opacification, eccentric location or subluxed IOL, retained cortex, Descemet’s flap and cystoid macular edema.

As the comanaging doctor, it is your job to identify these issues, so they can be treated appropriately.

FUTURE TREATMENT OPTIONS

The following IOLs are in the pipeline:

• Trifocals. These IOLs, available in Europe and Canada and undergoing U.S. clinical trials, combine two separate add power diffractive IOLs. The low add diffractive grating reinforces the higher add diffractive grating, providing an improvement in intermediate vision and maintaining far and near vision while producing less glare and halos.

• Extended depth of focus or extended range of vision IOLs. These, also available in Europe and Canada and undergoing U.S. clinical trials, have a proprietary diffractive echelette design that broadens the range of vision. Also, proprietary achromatic technology corrects chromatic aberration for better contrast sensitivity. These IOLs promise to provide a full range of high-quality vision.

TAKE CONTROL

Given that baby boomers comprise the second largest population in the U.S., behind millennials, and so many require cataract surgery, it’s imperative to their vision and the financial health of your practice that you play a significant role in their care. By being the first to diagnose a cataract and following the management protocol outlined here, these patients will see the value in sticking with you as their primary eye care provider. OM

DR. JOHNSTON practices at Georgia Eye Partners. He focuses on ocular surface disease and has extensive experience in comanaging cataract and refractive surgery patients. Email him at drj@gaeyepartners.com, or visit tinyurl.com/OMcomment to comment.