Phakic Intraocular Lenses as a Potential Treatment for Pigment Dispersion Syndrome

Pigment dispersion syndrome/pigment dispersion glaucoma (PDG) has no definitive cure and can cause vision loss in young myopes. Backward bowing of the iris can lead to rubbing of the pigmented epithelium against lens zonules and accumulation of pigment, obstructing aqueous humor outflow. We describe a case of a 37-year-old myopic man with PDG who presented to our clinic for a refractive surgery evaluation. The manifest refraction was -6.50 -0.50 x 107 in the right eye (oculus dexter (OD)) and -6.00 in the left eye (oculus sinister (OS)), which was correctable to 20/20 in both eyes (oculus uterque (OU)). Intraocular pressure (IOP) was 18 and 19 on latanoprost. Slit lamp examination revealed radial transillumination defects OU with superior and inferior thinning on nerve optical coherence tomography. Corneal topography and tomography were normal with a minimum pachymetry of 529 OD and 534 OS. Phakic intraocular lenses (IOLs; e.g., EVO implantable collamer lens (ICL)) were selected as a treatment option as they would fully correct the refractive error while providing a physical barrier between the zonules and posterior iris. On post-op day 1, the patient's uncorrected distance vision was 20/20+2 OD and 20/15 OS, with IOPs of 11 and 9 by Goldmann applanation tonometry, respectively. The ICL vault had an OD of 744 µm and an OS of 766 µm. At post-op month 1, reconfiguration of the iris contour from concave to parallel was observed. A six-month follow-up of latanoprost demonstrated stable IOP of 11 OD and 12 OS with no signs of worsening PDG in slit lamp examination or glaucoma imaging. Although larger and longer studies are needed, the newer generation of phakic IOLs, such as the EVO ICL, may have a therapeutic role in pigment dispersion by changing the iris configuration and creating a mechanical barrier between the zonules and the posterior iris.