Ocular function is fundamental for environmental adaptation and survival capacity. Growth factors are thought to be necessary to reach a mature eyeball and consequent adequate vision. However, the consequences of the deficiency of circulating growth hormone (GH) and its effector insulin-like growth factor I (IGF-I) on the physical aspects of the human eye are still debated. A model of untreated isolated GH deficiency (IGHD) may clarify this issue. The aim of this study was to assess the physical aspects of the eyeball of adult IGHD individuals who have never received GH therapy. A cross sectional study was carried out at the University Hospital, Federal University of Sergipe, Brazil, including 25 adult IGHD subjects homozygous for a null mutation (c.57+1G>A) in the GHRH receptor gene, and 28 matched controls. All underwent endocrine and ophthalmological assessment. The main outcome measures were visual acuity, intraocular pressure, refractive error, ocular axial length (AL), anterior chamber depth, and central corneal thickness (CCT). Despite unmeasurable serum IGF-I, there was no difference between the groups in visual acuity, intraocular pressure, and refractive error. IGHD subjects exhibited lower absolute values of AL (22.5±0.6 vs 23.5±1.0 mm, P< 0.0001), anterior chamber depth (2.98±0.3 vs 3.26±0.3 mm, P=0.001) and CCT (539±28 vs 546±28 mμ, P=0.04) than controls. All values were within their normal ranges. While mean stature in IGHD group was 78% of the controls, mean IGHD axial AL was 96%. These observations suggest no relevant consequences of congenital lack of pituitary GH and of circulating IGF-I on physical ocular findings. Autocrine or paracrine growth factors may be more relevant to ocular growth.
20 - 23 May 2017
European Society of Endocrinology