PATIENT COMPLAINTS FOLLOWING IOL IMPLANTATION

[caption id='attachment_1320' align='alignright' width='400' caption='Figure 1: Add-On Torica IOL'][/caption]

Most patient complaints following multifocal IOL implantation are easily treated, although a small percentage need a specific and more complex management, said Pascal Rozot MD, Clinique Monticelli, Marseille, France at the XXIX Congress of the ESCRS.

Poor patient satisfaction with multifocal IOLs can result from a wide range of causes, some temporary, such as eye dryness and inflammation during the early postoperative period, and some more persistent, such as residual ametropia, PCO, and intolerance of multifocality, Dr Rozot noted.

But so long as the physician can accurately diagnose the cause of the problem, a solution that results in a happy patient is almost always possible, he added.

Spherical error

Residual ametropia is the leading cause of patient dissatisfaction with multifocal IOLs, accounting for 65 per cent of complaints. Spherical error in general results in blurred uncorrected vision and so greatly reduces patients’ spectacle independence, he noted.

Residual myopic error not only reduces uncorrected distance visual acuity but also increases the intensity of haloes, and requires patients to bring reading material closer to their eyes. Residual hyperopic error, conversely, will require patients to hold reading materials further away, although it sometimes has the benefit of improved uncorrected intermediate vision.

Making a determination of residual refractive ametropia following multifocal implantation requires a wait of two weeks postoperatively to insure that the patients’ vision has stabilised adequately. It is also better to use subjective refraction because autorefractometry sometimes induces a myopic shift.

[caption id='attachment_1321' align='alignright' width='400' caption='Figure 2a: PCO developed on an AT.LISA IOL'][/caption]

In eyes with residual myopia, refractive errors of 0.5 D or less are best left untreated, said Dr Rozot. Corneal surgery such as PRK or LASIK remain a useful option in eyes with refractive errors ranging from -0.5 D to -1.5 D. For eyes with greater residual myopia, the main options are IOL exchange, if the multifocal IOL was implanted less than two months earlier, and piggy back IOLs, if the IOL had been implanted a longer time previously.

Dr Rozot recommended a similar strategy in eyes with residual hyperopia, although he said hyperopia of +0.75 D should be the upper limit for withholding any further intervention in the non-dominant eye. If the residual hyperopia is in the dominant eye, hyperopic PRK is again a possibility. However, in the case of three-piece multifocal IOLs another option is optic capture in the capsulorhexis. The technique brings the optic forward and thereby reduces the hyperopic error. For higher refractive errors the options are the same as in residual myopia.

Problems with astigmatism are less common since the advent of toric multifocal IOLs. However, when it does occur, PRK or LASIK is again an option for lower refractive errors in the dominant eye, and piggy back toric IOLs (Figure 1) offer a potential solution in eyes with higher amounts of cylinder.

PCO problems

PCO vies with residual ametropia as a leading cause for visual complaints following multifocal IOL implantation, accounting for more than half of dissatisfied patients in some series. Research has shown that minor amounts of PCO that would not bother most patients with monofocal IOLs can be very disturbing to patients with multifocal IOLs (Figure 2a).

[caption id='attachment_1322' align='alignright' width='400' caption='2b: OQAS assessment of PCO: increase of the ocular scattering index (OSI)'][/caption]

Surgeons should therefore be especially scrupulous in avoiding the complication in their multifocal patients, making sure to carry out a thorough capsule polishing during surgery, Dr Rozot emphasised. Tests for the impact of PCO can include pinhole visual acuity measurements and OQAS double-pass aberrometry (Figure 2b). When Nd-YAG capsulotomy becomes necessary it is best to use a large 5.0mm, cross-opening, beginning at periphery, to avoid marks on the optic and to reduce photic effects.

One rare but very persistent problem that can occur in some patients is intolerance of the split-vision optics of multifocal IOLs. The complication can occur in eyes where there are no objective signs of residual refractive error, or IOL decentration or tilt. It may have a neurological basis, Dr Rozot said.

“One hypothesis is that an imperfect blurred retinal image secondary to the multifocal pattern of the IOL increases the activation in the visual association areas of the occipital cortex, Dr Rozot said.

Removing the lens and replacing it with a monofocal lens improves visual satisfaction in 80 per cent of cases, but as with IOL exchange in general, it does entail the risks of inducing macular edema and other complications, he added.

Photic effects, dysphotopsias

Since their earliest days back in the late 1980s, multifocal IOLs have been associated with an increased amount of photic phenomena such as glare, haloes, and ghost images. Careful counseling of patients before and after surgery is generally adequate to relieve patients’ anxiety since the symptoms tend to become much less noticeable over time, Dr Rozot said.

[caption id='attachment_1323' align='alignright' width='400' caption='Figure 3: decentred multifocal IOL'][/caption]

Haloes occur in 10 to 20 per cent of patients, although they have become less common and less intense with modern IOLs, he noted. In the majority of cases patients no longer notice them after the first few postoperative months. However, they can be more bothersome in patients with photopic pupils greater 3.5mm in diameter. In such cases topical brimonidine can reduce the symptom, due to its pupil-constricting affect in scotopic or mesopic conditions, he added.

Ghost images are a rarer photic phenomenon and are generally the result of decentered IOLs (Figure 3). Re-positioning the IOL or exchanging it with another multifocal IOL will generally result in a satisfactory outcome, Dr Rozot added.

“There are currently many well-performing and well-tolerated multifocal IOLs and it remains a premium surgery for all levels of procedure. Therefore pre-, intra- and postoperative support must be as precise as possible,†he concluded.