At present, different proposed mechanisms inducing negative dysphotopsia symptoms have merged. Masket and Fram1 reported that negative dysphotopsia is likely induced at the interface of the anterior capsulotomy and the front surface of the PC IOL, suggesting that a reflection of the anterior capsulotomy edge is projected onto the nasal peripheral retina. Holladay and Simpson2 proved in their experimental study that a shadow is present when there is a gap between the retinal images formed by rays missing the optic of the IOL and rays refracted by the IOL.
For the 63-year-old patient in this case, does this mean that only a surgical intervention will help to solve his dysphotopsia problem? From the case description, I understand that the capsulorhexis is smaller than the 6.0 mm IOL optic and is well centered. Here in Germany, I would offer the patient (as the first solution) an IOL exchange with a Morcher 90S IOLA that will solve that problem instantly. This IOL has a groove in the optic in which the anterior capsule will fit while the haptic is implanted in the capsular bag. I recently used this technique to successfully treat a similar patient who had strong complaints about negative dysphotopsia; the symptoms were fully relieved after the existing IOL was exchanged for the 90S model.
As a second option, and because reverse optic capture did not work in this case, I would propose the piggyback technique with an EVO Visian Implantable Collamer Lens phakic IOL (pIOL) (version b, Staar Surgical Co.); this pIOL has no central hole and has a 6.1 mm optic. It is very thin, is designed for the ciliary sulcus, and is anteriorly curved, thus closing the distance between posterior surface of the iris and the in-the-bag IOL. I would implant the pIOL in the 0- to 180-degree axis. The optic has no sharp edges, and it is included in the plate haptic, which is made of collamer. This material is highly biocompatible and contains a UV light filter, which might reduce the blue-vision symptoms of the patient a bit.
In countries where this option is not available, one could try using the Affinity CQ2015A (Staar Surgical Co.). This 3-piece IOL has a 6.0 mm collamer optic with a haptic diameter of 13.0 mm. I have no experience using this as a piggyback IOL for treating negative dysphotopsia. Other add-on or supplementary IOLs, such as the Sulcoflex (Rayner Intraocular Lenses Ltd.) and the Addon (1stQ GmbH), did not solve negative dysphotopsia problems in my patients.
Neodymium:YAG laser treatment to remove or destroy the small overlap of the anterior capsule on the nasal and superior part of the optic would be a third minimally invasive option. This treatment requires a new-generation Nd:YAG laser with low energy (0.5 to 2.0 mJ) so the anterior capsule overlap can be excised precisely. The downside of this treatment is that the aforementioned IOL exchange with the 90S IOL is no longer possible.
In summary, my first choice in treating negative dysphotopsia in this case is an IOL exchange rather than implanting a piggyback IOL.
1. Masket S, Fram NR. Pseudophakic negative dysphotopsia: surgical management and new theory of etiology. J Cataract Refract Surg
2. Holladay JT, Simpson MJ. Negative dysphotopsia: causes and rationale for prevention and treatment. J Cataract Refract Surg
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