The current study involved analysis of the corneal tomographic parameters of patients with thyroid gland dysfunction (hyperthyroidism or hypothyroidism), including those with an autoimmune etiology, in comparison to healthy controls without TGD, using pentacam, in an attempt to detect possible early corneal changes and to highlight whether early screening of those patients would be necessary for early detection of KC.

A total of 100 eyes of 50 patients with TGD and 100 eyes of 50 healthy controls were enrolled. Diagnosis of TGD was based on history, clinical examination and laboratory investigations. Exclusion criteria included previous thyroid medications, thyroidectomy, previous ocular surgery, corneal pathology and other risk factors of keratoconus (KC). All eyes were examined by Pentacam, (Oculus Optikgerate GmbH, Wetzlar, Germany). Pentacam parameters were compared between TGD patients and controls. Spearman's correlation coefficient between different pentacam parameters and the level of free T4 and TSH was calculated.

Inclusion Criteria:

• For TGD patients: Patients with a recent diagnosis of TGD (the study group) were recruited from endocrinology outpatient clinic of Specialized Medical Hospital, Mansoura University. Diagnosis of TGD was based on précised history, clinical examination and laboratory investigations. In order to avoid bias, patients with history of intake of any thyroid-related medications (antithyroid medications or thyroxine replacement), radioactive iodine or thyroidectomy were excluded from the study. Therefore, we only included patients who did not received treatment yet For the control group, fifty age and gender matched healthy subjects without known personal or family history of thyroid disease or any autoimmune diseases were recruited from candidates of refractive surgery referred to the outpatient clinic of Mansoura Ophthalmology Center for pentacam assessment and who were proved to have normal corneal pentacam parameters. They were further examined by the endocrinologist to exclude thyroid dysfunction; this was supported by normal thyroid function profile (serum TSH and free T4) and negative anti-TPO and antithyroglobulin antibodies.

Exclusion Criteria:

• patients with previous thyroid medications or replacement therapy, thyroidectomy or radioactive iodine intake participants with a history of ocular surgery or trauma, use of any topical medication or contact lens wear, patients with any corneal pathology, Corneal dystrophy, corneal scarring or any concurrent ocular disease. To eliminate other risk factors for KC, we also excluded participants with a history of persistent eye rubbing, vernal keratoconjunctivitis (VKC), atopy, Down syndrome, Turner's syndrome, or congenital rubella. Pregnant or lactating females were also excluded from the study.

100 eyes of 50 patients with TGD (hypo-hyperthyroidism) and 100 eyes of 50 age and sex matched healthy controls.