Intraocular Lens Opacification in a Patient With Gyrate Atrophy With a Subluxated Intraocular Lens

Introduction

Intraocular lens opacification is a well-established progressive complication after uneventful cataract surgery that can eventually affect vision, which has been reported since the 1990s [1]. The etiology of opacification remains unknown. Some have hypothesized that faulty manufacturing or storage issues or even packaging materials are the causes of opacification. IOL opacification is rare; affecting 1 in 200 exchanged or explanted lenses. Opacifications can lead to symptoms such as glare and haloes and distorted image quality. Although opacification has been reported in various IOL materials, it is most commonly reported with hydrophilic acrylic lenses [2].

Gyrate atrophy is a rare metabolic disease affecting the choroioretinal structures, and is associated with developing posterior subcapsular cataracts early in life, usually by the mid-twenties, and requiring cataract surgery in the mid-forties. Patients with gyrate atrophy have zonulopathy, which carries the risk of lens subluxation. Previous studies have reported bilateral posterior dislocation of in-the-bag posterior chamber IOLs [3,4].

We report the presentation and management of a patient with gyrate atrophy who experienced late subluxation of a posterior chamber intraocular lens (IOL) and developed rosette-shaped lens opacities. This is the first reported case of calcium oxalate rosette-shaped opacities in an intraocular lens (IOL) in a patient with gyrate atrophy.

Case Report

A 37-year-old man presented with gyrate atrophy and a subluxated IOL with peculiar rosette snowflake-like deposits on the lens surface (Figure 1A, 1B). He was diagnosed with gyrate atrophy with mutations on the OAT gene (MIM613349) on chromosome 10q26 and was regularly assessed by the dystrophy clinic since 2012. On presentation, he had a history of unevenful cataract surgery with in-the-bag IOL implantation of the right eye in 2009 and in 2011 in the left eye at a private hospital. Both IOLs were single-piece acrylic hydrophobic lenses, but the exact type and manufacturer of the IOLs inserted were unknown, as no report was provided by the facility where the surgery was performed. In 2012, we documented an inferior IOL subluxation in the left eye and some lens opacities in the right eye. At that time, uncorrected vision was 20/300 in the right eye and 20/125 in the left eye, reaching 20/125 in the right eye and 20/80 in the left eye with correction.

In 2019, the patient was referred for IOL repositioning in the left eye for a temporally subluxated IOL and a nasal subluxation OD with snowflake-like deposits. He underwent IOL exchange in the left eye and his vision improved to 20/80. In October 2020, he was referred for decreased vision affecting mobility and navigation, with hand motion vision at 2 feet in the right eye.

In April 2021, he was reassessed and the examination indicated an unstable IOL in the right eye with inferior subluxation, pseudophacodonesis, and peculiar deposits on the anterior lens capsule and the IOL. Macula status was assessed and showed mild cystic changes.

The patient consented to IOL exchange with a 3-piece IOL with haptics secured to the scleral grove after anterior vitrectomy. The subluxated single-piece IOL was explanted and the anterior capsule was excised and sent for histopathology and microscopy (Figures 2, 3). During anterior vitrectomy, severe zonulopathy was noted, evidenced by mobilization of the capsular bag toward the vitrectomy probe. A 3-piece IOL was initially implanted in the sulcus, with its haptic placed away from the area of greatest zonular weakness. However, on the first postoperative day, the IOL was found to be subluxated inferiorly, bisecting the visual axis. Consequently, the patient was taken back to the operating room for IOL repositioning, where the haptics of the 3-piece IOL were securely tucked into scleral grooves to achieve stable fixation. The histopathology report indicated a small piece of PAS-positive thin membrane with remnant cortex. Microscopy indicated the IOL had unique round precipitates with some bifringence under polarization, suggestive of calcium oxalate. Postoperatively, the patient had 20/100 vision with a well-centered stable IOL (Figure 4). At his latest visit, in 2024, the IOL remained clear.

Discussion

Gyrate atrophy is a rare metabolic disease that is slowly progressive and affects vision due to choroidal dystrophy and cataract. It is caused by ornithine-aminotransferase (OAT) enzyme deficiency resulting in an increase in plasma ornithine concentrations. It also causes high ornithine levels in the urine, cerebrospinal fluid, and aqueous humor [5]. Loose zonules is a known finding in gyrate atrophy patients, which increases the risk of lens subluxation, making cataract surgery more challenging and outcomes less promising. There have been previous reports of bilateral posterior IOL dislocation into the vitreous warranting vitreoretinal intervention for explantation [3,4]. Previous histopathology studies of gyrate atrophy have reported liquefied and degenerated lens material at the region of the posterior sutures [6]. Some studies have reported IOL calcification following air or gas injection and pars plana vitrectomy [7]. Other studies have observed IOL calcification in hydrophilic and silicone lenses, and it has been hypothesized that the formation of calcium salts is related to calcium phosphate reaction, which might be related to an inflammatory process in the eye or intraoperative administration of substances rich in these elements [8]. Our patient developed very striking rosette-shaped snowflake opacities in the IOL. The gross examination revealed part of a single-piece IOL with multiple transparent crystals resembling calcium oxalate crystals on the IOL surface. The crystals on the IOL stained positive with von Kossa stain and showed similar prismatic birefringence with polarizing light. The calcium oxalate particles were on the surface and embeded in the IOLs and could not be easily scrapped off. To the best of our knowledge, these rosette snowflake opacities have never been reported in a patient without a history of a laser procedure or who had gyrate atrophy. Previous studies have demonstrated calcium phosphate crystals IOL depositions, but calcium oxalate depositions have not been reported. This could be explained by high ornithine levels in the aqueous humor, altering its chemistry and causing calcium oxalate precipitation.

Limitations of this report are that it describes a single case, and it lacks long-term follow-up data. Future larger-cohort studies are needed to verify the causal relationship between metabolic abnormalities and IOL calcification.

Conclusions

To the best of our knowledge, this is the first reported case of rosette snowflake-shaped opacities in a patient with gyrate atrophy. This case highlights the need for regular monitoring after cataract surgery for patients with gyrate atrophy, and specialized follow-up assessment of IOL position (eg, UBM/OCT assessment of zonular stability) and clarity (slit-lamp examination for opacity morphology) are recommended every 6-12 months postoperatively. Particular vigilance is advised for patients with concurrent OAT gene mutations.