Dorairaj, Emily

Adult optic nerve axon regeneration has traditionally been framed as a problem of limited intrinsic growth capacity in central nervous system neurons. However, growing evidence suggests that intrinsic factors alone cannot account for regenerative failure: restrictive extrinsic environmental factors largely govern optic nerve regeneration, dictating the intrinsic capacity axons can express. In this review, we frame the extrinsic optic nerve environment as a dynamic regenerative niche, in which vascular, immune, glial, matrix, and metabolic compartments are spatially co-localized and temporally coordinated rather than acting as independent barriers. These compartments follow a shared trajectory, broadly protective in the acute phase, then inhibitory once the underlying response fails to resolve, while also actively driving one another, such as reactive astrocytes promoting the matrix remodeling that subsequently restricts axon regrowth. Consequently, the niche’s overall permissiveness for regeneration reflects the aggregate and interdependent state of these compartments rather than the action of any single barrier. This review integrates current evidence on extrinsic barriers, intervention opportunities, and disease-specific variability relevant to RGC axon regeneration after injury. These interventions must incorporate the spatial, temporal, and metabolic factors that shape the goal of functional recovery and vision restoration.

Abstract Introduction Cystoid macular edema (CME) is a recognized complication associated with penetrating keratoplasty (PK) and Endothelial Keratoplasty (EK). The purpose of this study was to determine the incidence of acute CME within the first 6 months after PK, Descemet stripping automated EK, or Descemet’s membrane EK. Methods A retrospective cohort analysis of the TriNetX United States collaborative database was conducted. Patients with a diagnosis of Fuchs dystrophy or keratoconus who underwent PK or EK between January 1, 2004 and August 30, 2024 were included. Those with a history of uveitis, retinal vascular occlusion, diabetic macular edema, or prior vitrectomy were excluded. Outcomes and diagnoses were defined using current procedural terminology and International Classification of Diseases, Tenth edition (ICD-10) codes. Cohorts were stratified based on a history of prior PK or EK with >6 months follow-up. Propensity score matching was performed on both cohorts to control for age at index, sex, race, ethnicity, and the diagnosis of Fuchs dystrophy and keratoconus. The incidence of acute CME during a 6-month postoperative follow-up period was assessed. Odds ratios were calculated between cohorts. Results A total of 2516 eyes were included in the study (PK: 1258; EK: 1258). At six months postoperatively, the incidence of acute CME in the EK cohort (46 of 1258) was significantly higher than in the PK cohort (20 of 1258) (P = 0.0012) (OR 0.426, 95% confidence interval 0.25–0.72). Conclusions Our findings suggest that the incidence of acute CME is higher in patients undergoing EK compared to PK.

The incidence of both cataract and glaucoma is increasing globally. With increasing patient expectation and improved technology, premium intraocular lenses (IOLs), including presbyopia-correcting and toric IOLs, are being increasingly implanted today. However, concerns remain regarding the use of premium IOLs, particularly presbyopia-correcting IOLs, in eyes with glaucoma. This systematic review evaluates the use of premium IOLs in glaucoma. A comprehensive search of the MEDLINE database was performed from inception until 1 June 2023. Initial search yielded 1404 records, of which 12 were included in the final review of post-operative outcomes. Studies demonstrated high spectacle independence for distance and good patient satisfaction in glaucomatous eyes, with positive outcomes also in post-operative visual acuity, residual astigmatism, and contrast sensitivity. Considerations in patient selection include anatomical and functional factors, such as the type and severity of glaucomatous visual field defects, glaucoma subtype, presence of ocular surface disease, ocular changes after glaucoma surgery, and the reliability of disease monitoring, all of which may be affected by, or influence, the outcomes of premium IOL implantation in glaucoma patients. Regular reviews on this topic are needed in order to keep up with the rapid advancements in IOL technology and glaucoma surgical treatments.