title: Pachymetry map of corneal epithelium in children wearing orthokeratology contact lenses.
abstract: OBJECTIVE
  To study the pachymetry map of the corneal epithelium in children wearing orthokeratology lenses automatically generated by a Fourier-domain optical coherence tomography.
  
  
  METHODS
  The study was conducted on 60 children who had been fitted with myopic orthokeratology lenses. Patients were divided into two groups according to the duration of OK lens treatment (group 1: ≤14 days, n = 28; group 2: >14 days, n = 32). The control group consisted of 44 children. An FD-OCT device with a pachymetry module was used to map the central 6-mm corneal epithelial thickness. An epithelial thickness map was automatically generated and divided into three zones: central 2 mm, paracentral 2 to 5 mm (P1) and mid-peripheral 5 to 6 mm (P2). The average epithelial thickness of central (C), the temporal (T1), nasal (N1), superior (S1) and inferior (I1) sectors of P1, and the temporal (T2), nasal (N2), superior (S2) and inferior (I2) sectors of P2 were recorded and compared. The minimum and maximum points of epithelial thickness across the map were also recorded. Munnerlyn's formula was used to model the expected change in refractive error based on Δ(Max-Min) (Δ(Max-Min) = (Max-Min)study-(Max-Min) mean of control).
  
  
  RESULTS
  The central epithelial thickness was significantly different between individual groups and a significant difference from the control (Group 0) was seen in each treatment group. Both the epithelial thickness measurements of T1 and I1 were thinnest in Group 1. Both the epithelial thickness measurements of S2 and I2 were thickest in Group 2. The difference between maximum and minimum thickness was significantly different between groups with the largest effect in Group 2. The refractive changes predicted by Munnerlyn's formula were less than the actual refractive changes measured in both study groups.
  
  
  CONCLUSIONS
  The epithelial thickness map automatically generated by FD-OCT can provide regional information about corneal epithelium thickness following overnight wearing of OK lenses.
authors: Department of ophthalmology, Eye and ENT Hospital, Key laboratory of myopia of State Health Ministry, Fudan University , Shanghai , PR China and.
authors: Yishan
authors: Y
authors: Qian
authors: Feng
authors: F
authors: Xue
authors: Jia
authors: J
authors: Huang
authors: Xiaomei
authors: X
authors: Qu
authors: Xingtao
authors: X
authors: Zhou
authors: Devan Van
authors: DV
authors: Lanen-Wanek
mesh_terms: D000293:Adolescent; D000465:Algorithms; D002648:Child; D003261:Contact Lenses; D063171:Corneal Pachymetry / Q000379:methods*; D019573:Epithelium, Corneal / Q000473:pathology*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D009216:Myopia / Q000473:pathology / Q000628:therapy*; D054158:Orthokeratologic Procedures / Q000379:methods*; D012985:Software Design; D041623:Tomography, Optical Coherence / Q000379:methods*