Elevated IGF-1 and GH Levels Are Correlated With a Thicker Iris and Wider Anterior Chamber Angle in Treatment-Naïve Acromegaly Patients

Purpose

To compare the difference in anterior segment biometrics derived from anterior segment optical coherence tomography (AS-OCT) between treatment-naïve acromegaly patients and normal controls and evaluate the correlations between above biometrics and insulin-like growth factor 1 (IGF-1) and growth hormone (GH) levels.

Methods

Sixty eyes of 30 acromegaly patients and 60 eyes of 30 normal controls were included in this case-control study. Central corneal thickness, pupil diameter, iris thickness (IT), iris curvature (IC), anterior chamber depth (ACD), anterior chamber width, lens vault (LV), angle open distance (AOD) 500, AOD750, and trabecular iris space area (TISA) 500 and TISA750 were measured by AS-OCT. General linear regression models were constructed to evaluate the independent endocrine factors affecting iris morphology and anterior chamber angle (ACA) width.

Results

The acromegaly patients had an evenly thicker iris (P < 0.001), a smaller IC (P < 0.05), a smaller LV (P = 0.040) and significantly larger AOD500, AOD750, TISA500 and TISA750 (P < 0.001). There was a positive correlation between the serum GH level and ACD in the acromegaly patients (P = 0.031). Linear regression models showed the lower LV and smaller IC were independent influencing factors of the increase in the AOD500, AOD750, and TISA750 and nasal TISA500. Serum IGF-1 was an independent factor for the increase in pupil diameter (β = 0.002, P = 0.031) and both the average nasal (β = 6.781*10⁻⁵, P = 0.049) and temporal (β = 7.736*10⁻⁵, P = 0.045) IT values and for the decrease in temporal IC (β < 0.001, P = 0.037). GH was an independent factor for the increase in temporal AOD750 (β = 0.001, P = 0.030) and temporal TISA750 (β = 0.002, P = 0.016).

Conclusions

Patients with acromegaly have a thicker IT, smaller IC, and lower LV with a wider ACA than normal controls. Serum GH is independently correlated with the temporal ACA width, whereas serum IGF-1 is independently correlated with IT, pupil diameter, and IC.