Lacrimal gland enlargement and tear film changes in acromegaly patients: A controlled study
Introduction
Acromegaly is a disease with high serum growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels. Pituitary tumors are responsible for more than 95% of the acromegaly cases. The worldwide annual incidence of the disease has been reported to be 40–70 per million individuals [1]. The clinical findings can originate due to the hypersecretion of GH or the compressive effect of the pituitary mass. Hypersecretion of GH causes characteristic acral growth, enlarged lip and nose, increased skin thickness, and frontal bone hypertrophy as well as multiple organomegalies. Its ocular findings include bitemporal hemianopsia, vision loss, corneal or intraocular pressure changes [2], decreased tear breakup time (TBUT) [3], increased choroidal thickness [4], and decreased endothelial cell density [5]. Despite the findings of multiple organomegalies, to date, its effect on the lacrimal gland volume and function has not been evaluated with a case-control study.
The aqueous portion of the tear film is secreted from the lacrimal gland and accessory glands. The tear secretion from the lacrimal gland is regulated by several hormonal and neural systems and it can be affected by various diseases. Decreased tear film secretion or increased evaporation of the tear film can cause dry eye syndrome and various tests such as the Schirmer test, TBUT, ocular surface disease index (OSDI) scores can be used for the diagnosis of dry eye syndrome.
Increased IGF-levels in patients with acromegaly can cause an increase in the volume of several major organs including the liver, heart, etc. Although the initial findings of two acromegaly patients were reported as proptosis and epiphora in a previous report [6], the effect of GH and IGF-1 on the lacrimal gland is unclear. Furthermore, the effect of lacrimal gland volume on the tear film functions is also unclear. In a recent study, mice with experimentally induced dry eye syndrome showed decreased lacrimal gland volume [7]. In another study, patients with primary acquired nasolacrimal duct obstruction showed decreased lacrimal gland volume [8]. However, further studies are needed to evaluate the effect of increased lacrimal gland volume on the tear film functions.
In this study, we aimed to investigate the change in the lacrimal gland volume of the patients with controlled or uncontrolled acromegaly compared to a control group at the baseline, 3rd-month, and 6th-month visits and to evaluate the effect of any change on the tear film functions. We also aimed to investigate the relationship of any possible changes with the serum IGF-1 and GH levels.
Section snippets
Patients
This prospective multidisciplinary study included patients with controlled or uncontrolled acromegaly as the study groups and patients with nonfunctioning pituitary adenoma (NFA) as the control group. The patients were recruited to the study from the Endocrinology and Neurosurgery departments. NFA was preferred as the control group due to the presence of prospective orbital MRI images of the patients at the same time points of this study. Uncontrolled acromegaly patients were included in the
Results
After the application of the inclusion criteria, 38 eyes of 38 patients with UA, 48 eyes of 48 patients with CA, and 44 eyes of 44 patients with NFA were included in the study. The mean age was 46.4 ± 12.8 years for all acromegaly patients (n = 86) and 47.5 ± 11.0 for NFA patients (p = 0.542). While 57 (66.3%) of the acromegaly patients were female and 29 (33.7%) were male, 30 (68.2%) of the NFA patients were female and 14 (31.8%) were male (p = 0.827).
The mean duration of the disease for the
Discussion
Acromegaly is a disease having multisystemic effects by increased serum GH and IGF-1 levels. This prospective case-control study on controlled and uncontrolled acromegaly patients showed that acromegaly patients had at least 1.5 times larger lacrimal gland volume compared to a control group and this volume increase was maintained for 6 months of follow-up. While this change in the LGV did not show a change in the tear film functions in acromegaly patients, IGF-1 levels showed a positive
Conflicts of interest and source of funding
The authors have nothing to disclose, there is no conflict of interest.
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