January consultation # 2

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The most common cause of glare after refractive surgery is residual refractive error. This patient has significant residual refractive error. To determine whether the glare is due to the refractive error or aberrations caused by the pupil being larger than the IOL optic, a spectacle trial is indicated. For the trial, the patient is given manifest refraction in spectacles. The patient wears the spectacles for night driving and reports to the physician whether the symptoms of glare and halos were alleviated.

If spectacles alleviate the symptoms of glare and halo, laser in situ keratomileusis (LASIK) enhancement is indicated. In light of the large incision required to implant the toric Artisan pIOL, enhancement must be deferred until all sutures are removed and the wound is sufficiently healed to handle the pressure of the microkeratome incision. My custom is to perform LASIK 6 months after implantation of the Artisan pIOL.

If a spectacle trial does not alleviate the glare (and I believe it would not in this patient), the glare is largely the result of the pupil being larger than the IOL. This pIOL has a 5.0 mm optic. In the early days of Artisan pIOL implantation, the 6.0 mm optic was not available, so lenses with a 5.0 mm optic were routinely used. Glare was common. In my experience, there is a stronger relationship between pupil size and night-vision complaints with pIOLs than with LASIK, where the relationship seems to be nonexistent. With pIOLs, however, there seems to be a much clearer relationship. This may be because of the abrupt transition in refractive power that occurs at the edge of the IOL. A similar phenomenon is observed with pseudophakic IOLs. The surface area of a 6.0 mm optic is 44% greater than that of a 5.0 mm optic, which causes a significant increase in the area of the photopic pupil covered by the IOL. In my experience, the 6.0 mm optic produces significantly better night vision.

This patient now has against-the-rule astigmatism. The astigmatism was significantly overcorrected: The right eye obtained about 4.75 D of surgically induced astigmatic change, and the left eye obtained 3.25 D. This may indicate an IOL power error but more likely represents relaxation of a loosely sutured superior incision. A dilated examination is indicated to rule out a partially dislocated crystalline lens, which can also induce astigmatism.

Pharmacologic pupil constrictors are generally not well liked by patients. Given that the astigmatism was significantly overcorrected and that the 5.0 mm optic is not optimal in this patient with large pupils, the best procedure would be an IOL exchange, removing the 5.0 mm pIOL and replacing it with a 6.0 mm Artisan pIOL. The pIOL spherical power calculation would be designed to produce an additional −0.50 D of myopic correction than the original lens because of the −0.50 D of residual SE myopia in both eyes. The astigmatic power should be reduced appropriately because of the overcorrection of astigmatism. The pIOL exchange should be expected to reduce the residual refractive error and significantly improve night vision.