Evaluation of Retinal Layers by Optical Coherence Tomography in Patients with Acromegaly

Objectives: Acromegaly, a rare endocrine disorder caused primarily by growth hormone (GH) secreting pituitary adenomas, leads to elevated levels of growth GH and insulin-like growth factor 1 (IGF-1), resulting in systemic complications and ocular manifestations. These include increased corneal thickness, elevated intraocular pressure, retinal changes, and visual field defects. Spectral-domain optical coherence tomography (SD-OCT) enables high-resolution, non-invasive assessment of individual retinal layers. This technique provides a thickness map of the following seven different retinal layers via automatic segmentation: retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE). This study employed SD-OCT to evaluate the thickness of seven distinct retinal layers in patients with acromegaly, addressing a gap in the current literature. Materials and Methods: This cross-sectional comparative study included patients with acromegaly and age- and gender-matched healthy controls. Data collected included demographics, treatment modalities, disease activity status (remission vs. non-remission), and IGF-1 levels. A single-blinded ophthalmologist performed OCT. The thickness of seven distinct retinal layers was compared between acromegaly patients and controls. Results: The study included 23 acromegaly patients and 18 healthy controls, with 46 and 36 eyes evaluated, respectively. The acromegaly group exhibited significantly reduced median thicknesses in the RNFL, GCL, IPL, and RPE layers compared to controls (p<0.05), while INL, OPL, and ONL showed no differences. Subgroup analysis revealed that INL thickness was significantly greater in non-remission patients than in those in remission (p=0.022). Conclusion: Retinal layer thinning, particularly in the RNFL, GCL, IPL, and RPE, was observed in acromegaly patients compared to healthy controls.Interestingly, patients with active disease had thicker retinal layers than those in remission, suggesting a role for IGF-1 in these changes. As the first comprehensive evaluation of all seven retinal layers in acromegaly, this study highlights the need for further research to clarify these findings and the impact of IGF-1 on retinal structure.