January consultation # 6

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In this borderline case, a decision had to be made between LASIK and pIOL implantation. The surgeon chose Artisan pIOL implantation. First, I would want to know the postoperative cycloplegic refraction and determine the postoperative pIOL position and pupillometry. Artisan pIOL implantation can increase pupil diameter perpendicular to the axis of implantation. This might be one reason for the patient's visual disability due to the disparity between the useful optical area of the pIOL and the pupil diameter, which causes night glare because of light dispersion at the lens edge. A residual hyperopic refraction added to the resulting astigmatism could be the cause of fluctuating vision. A low degree of anisometropic refraction and the intermittent activation of accommodation by the dominant eye might also be reasons for some symptoms.

As this information is not available from the case report, my advice would be to exchange the Artisan pIOL for a toric implantable contact lens (ICL). The patient's complaints will be reduced as the posterior chamber phakic lenses provide a nodal point closer to the one of the eye (even though the concept of a “nodal point” for the eye is an oversimplification) and create less conflict with pupil size. Even with this solution, the patient should be alerted that because of the large pupil diameter, she might experience halos under extreme light conditions. If this were the case, I would handle this situation with brimonidine at night. Nevertheless, most, if not all, my patients with posterior chamber ICLs have not had a long-term problem with night halo symptoms.

The preferred surgical technique to exchange the pIOL would use peribulbar anesthesia. The dominant eye should be operated on first. Surgery should take into account the position of the pIOL and that a scleral incision, if left unsutured, could lead to a change in astigmatism, as seems to be the case. I would use a scleral tunnel to explant the pIOL. To avoid lens trauma, I would not use preoperative mydriatics. I would use a cohesive ophthalmic viscosurgical device (OVD) such as sodium hyaluronate 1% (Healon) to protect the corneal endothelium during pIOL explantation. Then, I would evacuate part of the cohesive OVD and replace it with methylcellulose to avoid a high volume of cohesive OVD in the anterior chamber, which would prevent adequate implantation of the ICL. I would disinsert the Artisan lens from the iris claw using an MICS capsulorhexis forceps (Katena) and iris spatula. Next, I would dilate the pupil using intraocular mydriatics (phenylephrine 10% and cycloplegic 1%, preservative free, 0.1 cc) to achieve an adequate 6.0 mm pupil dilation. The ICL would be implanted, increasing the volume of methylcellulose in the anterior chamber. After additional methylcellulose is placed in the anterior chamber, the ICL would be implanted at the adequate axis, which would have been marked preoperatively with reference to the horizontal position with the patient standing. To calculate the axis of the cylinder, I would use corneal topography from 2 or 3 months after surgery as changes in the corneal astigmatism could have occurred. The preoperative refraction before Artisan pIOL implantation would serve as a guide to calculate the power of the sphere and cylinder. Once the ICL is implanted, I would remove the OVD by irrigation/aspiration through the paracentesis and then carefully suture the scleral incision.

I would wait for at least 1 month to perform similar surgery in the nondominant eye. In some cases, once the dominant eye has improved, the patient becomes more tolerant of night symptoms. In such cases, surgery in the nondominant eye might be avoided.

Antibiotic prophylaxis with cefuroxime 1% would be used intracamerally at the end of surgery. I would also use topical steroid and cycloplegic agents in the early postoperative period to compensate for and prevent the inflammatory reaction that would follow iris manipulation.