title: Evaluation of retinal nerve fiber layer thickness profile in thyroid ophthalmopathy without optic nerve dysfunction.
abstract: OBJECTIVE
  To evaluate retinal nerve fiber layer (RNFL) thickness profile in patients of thyroid ophthalmopathy with no clinical signs of optic nerve dysfunction.
  
  
  METHODS
  A prospective, case-control, observational study conducted at a tertiary care centre. Inclusion criteria consisted of patients with eyelid retraction in association with any one of: biochemical thyroid dysfunction, exophthalmos, or extraocular muscle involvement; or thyroid dysfunction in association with either exophthalmos or extra-ocular muscle involvement; or a clinical activity score (CAS)>3/7. Two measurements of RNFL thickness were done for each eye, by Cirrus HD-optical coherence tomography 6mo apart.
  
  
  RESULTS
  Mean age of the sample was 38.75y (range 13-70y) with 18 males and 22 females. Average RNFL thickness at first visit was 92.06±12.44 µm, significantly lower than control group (101.28±6.64 µm) (P=0.0001). Thickness of inferior quadrant decreased from 118.2±21.27 µm to 115.0±22.27 µm after 6mo (P=0.02). There was no correlation between the change in CAS and RNFL thickness.
  
  
  CONCLUSIONS
  Decreased RNFL thickness is an important feature of thyroid orbitopathy, which is an inherent outcome of compressive optic neuropathy of any etiology. Subclinical RNFL damage continues in the absence of clinical activity of the disease. RNFL evaluation is essential in Grave's disease and active intervention may be warranted in the presence of significant damage.
authors.affiliation: Department of Ophthalmology, King George's Medical University, Lucknow 226003, India.
authors.forename: Kumari
authors.initials: K
authors.lastname: Mugdha
authors.affiliation: Department of Ophthalmology, King George's Medical University, Lucknow 226003, India.
authors.forename: Apjit
authors.initials: A
authors.lastname: Kaur
authors.affiliation: Sankara Eye Hospital, Kanpur 208001, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Sinha
authors.affiliation: Department of Ophthalmology, King George's Medical University, Lucknow 226003, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Saxena
keywords: optical coherence tomography; retinal nerve fibre layer; thyroid ophthalmopathy