Outcomes following cataract surgery in choroideremia

Frequency and Distribution of Ophthalmic Surgical Procedures among Patients with Inherited Retinal Diseases

OBJECTIVE

In this study, we aimed to characterize the frequency and distribution of ocular surgeries in patients with inherited retinal diseases (IRDs) and evaluate associated patient and disease factors.

DESIGN

Retrospective cohort.

PARTICIPANTS

Subjects aged ≥ 18 years who were followed at the Johns Hopkins Genetic Eye Disease Center.

METHODS

We studied a retrospective cohort of patients with an IRD diagnosis to analyze the occurrence of laser and incisional surgeries. Subjects were categorized into 2 groups: central dysfunction (macular/cone/cone-rod dystrophy, "MCCRD group") and panretinal or peripheral dysfunction (retinitis pigmentosa-like, "RP group"). Genetic testing status was recorded. The association of patient and disease factors on the frequency, distribution, and timing of surgeries was analyzed.

MAIN OUTCOME MEASURES

Prevalence, prevalence odds ratio (POR), hazard ratio (HR) of ophthalmic procedures by phenotype.

RESULTS

A total of 1472 eyes of 736 subjects were evaluated. Among them, 31.3% (n = 230) had undergone ocular surgery, and 78.3% of those (n = 180/230) had a history of more than 1 surgery. A total of 602 surgical procedures were analyzed. Cataract extraction with intraocular lens implantation (CEIOL) was the most common (51.2%), followed by yttrium aluminum garnet capsulotomy, refractive surgery, retinal surgery, and others. Cataract extraction with intraocular lens implantation occurred more frequently in RP than in MCCRD subjects (POR, 2.59; P = 0.002). Retinitis pigmentosa subjects underwent CEIOL at a younger age than patients with MCCRD (HR, 2.11; P < 0.001).

CONCLUSIONS

Approximately one-third of patients with IRD had a history of laser or incisional surgery. Cataract extraction with intraocular lens implantation was the most common surgery; its frequency and timing may be associated with the IRD phenotype. This data may inform the design of prospective research. Such efforts may illuminate routine clinical decision-making and contribute to surgical strategy development for cell and gene therapy delivery.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Choroideremia: from genetic and clinical phenotyping to gene therapy and future treatments

Choroideremia is an X-linked inherited chorioretinal dystrophy leading to blindness by late adulthood. Choroideremia is caused by mutations in the CHM gene which encodes Rab escort protein 1 (REP1), an ubiquitously expressed protein involved in intracellular trafficking and prenylation activity. The exact site of pathogenesis remains unclear but results in degeneration of the photoreceptors, retinal pigment epithelium and choroid. Animal and stem cell models have been used to study the molecular defects in choroideremia and test effectiveness of treatment interventions. Natural history studies of choroideremia have provided additional insight into the clinical phenotype of the condition and prepared the way for clinical trials aiming to investigate the safety and efficacy of suitable therapies. In this review, we provide a summary of the current knowledge on the genetics, pathophysiology, clinical features and therapeutic strategies that might become available for choroideremia in the future, including gene therapy, stem cell treatment and small-molecule drugs with nonsense suppression action.

Pathogenic mechanisms and the prospect of gene therapy for choroideremia

INTRODUCTION

Choroideremia is a rare, X-linked disorder recognized by its specific ocular phenotype as a progressive degenerative retinopathy resulting in blindness. New therapeutic approaches, primarily based on genetic mechanisms, have emerged that aim to prevent the progressive vision loss.

AREAS COVERED

This article will review the research that has progressed incrementally over the past two decades from mapping to gene discovery, uncovering the presumed mechanisms triggering the retinopathy to preclinical testing of potential therapies.

EXPERT OPINION

While still in an evaluative phase, the introduction of gene replacement as a potential therapy has been greeted with great enthusiasm by patients, advocacy groups and the medical community.