Advanced bilateral glaucoma decades after first-generation Fyodorov ‘collar-button’ anterior–posterior phakic intraocular lens implantation: a case report and clinical management considerations

Background Phakic intraocular lenses (pIOLs), used to correct high refractive errors, have since been associated with long-term complications including glaucoma and cataract formation. Elevated intraocular pressure (IOP) in these patients can be challenging to manage, often requiring surgical intervention. Micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) offers a less invasive option for IOP control in refractory cases. This report describes a patient with advanced glaucomatous optic neuropathy decades after undergoing pIOL implantation and the successful use of MP-TSCPC. Case presentation A 45-year-old male presented in June 2023 with advanced glaucomatous optic neuropathy following bilateral implantation of a first-generation Fyodorov “collar-button” phakic intraocular lens (pIOL) performed 25 years earlier. The patient experienced worsening vision in both eyes. Visual acuity testing, slit-lamp examination, static visual field (VF) assessment, anterior and posterior segment optical coherence tomography (AS-OCT, PS-OCT), pattern and flash visual evoked potentials (PVEP/FVEP) were performed. Corrected distance visual acuity (CDVA) was 0.9 in the RE and 1.0 in the left eye LE on the Snellen chart. Corrected near visual acuity (CNVA) was 0.5 on the Jaeger chart in both eyes. IOP was 26 mmHg in the RE and 24 mmHg in the LE. Slit-lamp examination revealed the presence of pIOLs with anterior capsular cataracts in both eyes. Fundoscopy showed severe glaucomatous optic neuropathy. Gonioscopy indicated a 30-degree angle width with grade 3 trabecular pigmentation. Visual field testing revealed advanced scotomata. PS-OCT confirmed severe ganglion cell and retinal nerve fiber loss. Performed examinations confirmed bilateral glaucomatous optic nerve atrophy. Despite the use of antiglaucoma medications, IOP remained elevated 3 weeks later measuring 23 mmHg in the RE and 21 mmHg in the LE. Due to persistently elevated intraocular pressure (IOP) despite pharmacological treatment, micropulse transscleral cyclophotocoagulation (MP-TSCPC) was performed in the right eye (RE). Following MP-TSCPC in the RE, the IOP decreased to 16 mmHg. The LE was managed pharmacologically, achieving favorable outcomes. Conclusion Long-term follow-up is essential in patients with anterior chamber phakic IOLs due to the risk of progressive complications such as cataract formation and secondary glaucoma. Early diagnosis of glaucoma could have prevented advanced optic nerve damage in the presented patient. In complex cases with multiple potential causes of visual impairment, electrophysiological examinations may serve as a supportive tool in the differential diagnosis of optic neuropathies.