Chapter 18

Eric Donnenfeld, MD; Alanna Nattis, DO; Eric Rosenberg, DO; and Allon Barsam, MD, MA, MRCOphth

PREOPERATIVE EDUCATION

There are several important steps that dramatically increase postoperative success with refractive intraocular lens (IOL) cataract surgery. In general, cataract surgery, and more specifically premium IOL cataract surgery, requires careful patient selection and counseling, along with precise surgical technique. Recent design advances in IOLs have resulted in excellent visual outcomes after cataract surgery.¹ As a result, many patients now have higher expectations for vision following surgery, including complete spectacle independence.¹ The use of diffractive multifocal IOLs is an effective way to satisfy the desire for excellent distance and near vision.¹ The principle by which diffractive IOLs work is to provide a focused image with zero order diffraction for distance vision, and first order diffraction for near vision.¹ However, with this optical setup, the focused retinal image will always be overlaid by an out-of-focus image from another diffractive portion of the lens, and also by background light, or light scattering due to diffraction inefficiency.1 This phenomenon often results in unintended adverse effects after implantation of diffractive multifocal/accommodative IOLs, including decreased contrast sensitivity and unwanted dysphotopsias, such as glare and halos.¹

For the less experienced surgeon, the best candidates for multifocal or accommodative IOLs are hyperopes or higher myopes who are motivated to reduce their dependence on spectacles, and who have more significant cataracts with minimal astigmatism. Both emmetropes and low myopes may feel that their distance or near vision was better prior to surgery than with a presbyopic IOL and should be counseled accordingly. Multiple options of add power allow physicians and patients to make individualized choices, in terms of target diopters, to customize patients’ lenses to their lifestyle.¹ For example, lower add power provides better intermediate vision for using computers and electronic devices.1 Patients often perform best with bilateral multifocal or accommodative IOL implantation and usually have the second cataract surgery completed within 1 month of the first surgery.

Multifocal IOL implantation requires the same surgical technique as conventional monofocal cataract surgery. However, optic insertion of these presbyopic lenses requires precise centration, necessitating a well-centered capsulorrhexis and good zonular integrity in order to achieve optimal visual results. Control of astigmatism alongside accurate biometry with advanced technology, such as the IOLMaster or Lenstar, is essential in maximizing outcomes. The lens constant must be carefully personalized to the individual surgeon. For this reason, tracking postoperative results is imperative to refine surgical outcomes. Postoperative astigmatism should be reduced to 0.5 diopter (D) or less. Refractive errors in general, and notably in patients with astigmatism, have a greater effect on quality of vision in multifocal IOL patients than in monofocal IOL patients. For patients with astigmatism greater than 0.5 D, limbal relaxing incisions (LRI), LASIK, or photorefractive keratectomy (PRK) may be required, and the patient should be informed about this prior to surgery.

In patients who are seeking spectacle independence but have significant preoperative astigmatism, a multifocal IOL may not be the best option. Toric multifocal IOLs, such as the AcrySof ReSTOR (Alcon) and other lenses on the horizon, combine diffractive optics with a toric component, thus offering astigmatic patients the option of having a multifocal IOL.² Toric multifocal IOLs have been found to result in increased spectacle independence and improved ability to perform near, intermediate, and distance tasks.² Despite the ability to produce spectacle independence, toric multifocal IOLs are not without drawbacks, such as diminished contrast sensitivity, halos, and/or glare.² Monofocal toric, or accommodating toric IOLs (Trulign [Bausch & Lomb]) offer excellent quality of vision and may be preferable options to discuss with the patient. Toric monofocal IOLs are also better options for patients with other coexisting ocular pathology. Patients with dry eye, macular pathology, glaucoma, or optic nerve disease may be relative or absolute contraindications to multifocal IOLs but do very well with toric monofocal IOLs. The only patient who should not be considered for a toric IOL is the patient who wishes to wear a gas permeable contact lens following surgery, such as those individuals with keratoconus.

The first step in any refractive procedure is to determine the patient’s visual requirements. Clinicians should fully educate their patients about possible postoperative symptoms and carefully interview them about lifestyle and postoperative expectations before selecting an IOL.¹ Asking the patients to complete a questionnaire like the one shown in Figure 18-1 (originally described by Steven Dell) is very helpful for this purpose. It is important to understand the differences between the various presbyopic IOLs in order to tailor the IOL choice to the needs of the individual patient.

Patient understanding of acceptable and expected surgical outcomes is imperative for the achievement of optimal results. Patients with unrealistic expectations for visual improvement and patients with excessive complaints about spectacles or contact lenses may not be optimal candidates for multifocal IOLs. This may also be true for patients whose occupation requires significant night driving and those who experience excessive glare and halo at night. There are many different multifocal IOLs currently available, with different adds that range from 2.5 to 4.0 D. Patients who wish to perform fine near tasks such as threading a needle may prefer the high add IOLs, and patients who spend more time at a computer or using a smart phone will appreciate the lower add multifocal IOLs. In general the risk of visual disturbance, such as glare and halo, is greatest with the higher add IOLs, while quality of vision is better with the lower adds. The size of halo experienced is proportional to the size of the out-of-focus retinal image produced by the IOL, which depends on the add power.1 However, even though the halo may be smaller with lower add powers, the intensity of halo may be greater, and therefore it will impact how a patient experiences his or her visual symptoms.¹ In addition, topical nonsteroidal anti-inflammatory drugs (NSAID) should be used perioperatively to decrease the risk of subclinical cystoid macular edema (CME) and thereby improve retinal and visual function.³

The next step in dealing with presbyopic IOL patients is to set realistic expectations preoperatively. Always talk to patients before surgery about common concerns such as glare, halo, quality of vision, residual refractive error, and the need for enhancements. Preoperative glare testing may be useful as well.1 Chair time spent with these patients before surgery pays dividends later on. For example, when informing a patient that he or she may experience postoperative dysphotopsias, he or she will be prepared for the problem should it result. However, if they are not adequately informed preoperatively, it will be perceived as a complication.

MANAGEMENT OF THE UNHAPPY POSTOPERATIVE PATIENT: THE SEVEN CS

When a patient is unhappy following cataract surgery, our technicians are instructed to perform a refraction, topography, and optical coherence tomography (OCT) prior to the surgeon evaluating the patient. Residual refractive error is the most common reason patients are unhappy. Residual error is evaluated with refraction, while the residual cylinder that could be missed with refraction is diagnosed with topography. In addition, the topography will show dropout, as evidenced by white areas where the tear film has been disrupted. Topography can be extremely valuable in diagnosing dry eye and ocular surface disease. OCT will help diagnose CME, in addition to any other macular pathology that might have been overlooked. By following these steps and the 7 Cs that follow, the most common problems leading to postoperative visual complaints will be identified. The primed ophthalmologist may now walk into the patient’s room, give an informed expert opinion as to why the patient might be dissatisfied, and suggest solutions immediately. Our patients who are unhappy know that we are working with them to try to resolve their problems.

There are 7 different causes of unhappy patients after refractive IOL implantation, which should be looked for in any patient who is not completely satisfied following presbyopic IOL cataract surgery.

Consecutive Treatment

When implanting presbyopic IOLs, it is important to tell patients that they will likely be dissatisfied with their vision after only one eye has been operated on. It is expected that patients will not be fully functional until the second IOL is placed, and they should be informed about this preoperatively. The importance of having both eyes completed is critical for the success of the procedure, along with providing for an adequate neuroadaptation period. However, in the rare circumstance that the patient is extremely unhappy following surgery on the first eye, we do not recommend operating on the second eye until the first surgical result has been optimized. The second IOL choice may be predicated on the patient’s response to the first surgery.

Presbyopic IOL patients are incredibly sensitive to small refractive errors, and the surgeon must be willing and able to treat these errors. Any astigmatism greater than 0.50 D in a symptomatic patient should be evaluated for treatment. LRIs can be useful in up to 1.50 D of cylinder, while surface ablation or LASIK provides more accurate results in patients with more than 1.50 D of cylinder. For patients with high cylinder, it is reasonable to debulk the refractive error with an LRI, followed by fine-tuning with the excimer laser. In patients with toric IOLs, it is important that the IOL be placed at the correct axis. For every 1 degree the IOL is off axis, there is a 3% loss of astigmatic correction. Newer technology such as intraoperative aberrometry and devices like the Verion (Alcon) and Callisto (Carl Zeiss Meditec) that display the axis of astigmatism intraoperatively can help refine cylinder outcomes. For patients with residual cylinder following toric IOL implantation, the website www.astigmatismfix.com is helpful in determining the correct axis for the physician to rotate the IOL.

Capsular Opacification

Multifocal IOL patients in particular are extremely sensitive to any opacification of the posterior capsule. The loss of contrast sensitivity and the glare created by the multifocal IOL is made worse by any capsular opacity. Depending on the patient’s complaint and mesopic/scotopic pupil size, multifocal IOL patients may require a larger capsulotomy than normal. An important consideration is that once the posterior capsule is opened, it makes a safe IOL exchange increasingly more difficult. Therefore, it is important to be sure that the capsule is the problem before proceeding. We commonly communicate to patients that when we “break” the posterior capsule, they “buy” the IOL.

Cystoid Macular Edema

The best way to look for CME after cataract surgery is with OCT. In addition, OCT is a very effective screening tool preoperatively for epiretinal membranes and lamellar macular holes. Patients who have undergone conventional cataract surgery without capsular breakage and have no risk factors have up to a 70% chance of developing macular thickening on OCT.³ Without the use of a topical NSAID, these same patients also have a 12% chance of developing visually significant CME.⁴ In addition, the loss of contrast sensitivity associated with a multifocal IOL is made much worse by CME.⁵ Once the normal architecture of the retina is lost, that visual quality is degraded for life. Snellen visual acuity will improve, but the contrast sensitivity will be permanently reduced. Multifocal IOL patients will not tolerate the lenses if they have significant maculopathy.⁶ We recommend using a topical NSAID for 3 days preoperatively and continuing it for 4 to 6 weeks postoperatively to help prevent CME.

Cornea and Ocular Surface Disease

Vision starts with the tear film, as the tear film is the most important refracting surface of the eye. The concept of stressing the visual system also applies to ocular surface disease, which is a common problem in presbyopic patients. Even mild disruption of the tear film greatly impacts the quality of vision. Patients without dry eye receiving bilateral multifocal IOL implantation had significantly improved mesopic and scotopic contrast sensitivity in the eye that received topical cyclosporine compared with eyes that received only an artificial tear7 (Figure 18-2). In addition, these patients were more satisfied with the eye that received the topical cyclosporine.⁷ When assessing the tear film, the meibomian glands must be evaluated. New treatments with re-esterified oral omega-3 nutritional supplements, hot compresses, and topical azithromycin have been shown to dramatically improve lid function.⁸ A more regular tear film and ocular surface will also help to improve the quality of vision.

Stay updated, free articles. Join our Telegram channel

Join