title: Ocular forward light scattering and corneal backward light scattering in patients with dry eye.
abstract: OBJECTIVE
  To evaluate ocular forward light scattering and corneal backward light scattering in patients with dry eye.
  
  
  METHODS
  Thirty-five eyes in 35 patients with dry eye and 20 eyes of 20 healthy control subjects were enrolled. The 35 dry eyes were classified into two groups according to whether superficial punctate keratopathy in the central 6-mm corneal zone (cSPK) was present or not. Ocular forward light scattering was quantified with a straylight meter. Corneal backward light scattering from the anterior, middle, and posterior corneal parts was assessed with a corneal densitometry program using the Scheimpflug imaging system.
  
  
  RESULTS
  Both dry eye groups had significantly higher intraocular forward light scattering than the control group (both P<0.05). The dry eye group with cSPK had significantly higher values in anterior and total corneal backward light scattering than the other two groups. Moderate positive correlations were observed between the cSPK score and corneal backward light scattering from the anterior cornea (R=0.60, P<0.001) and corneal backward light scattering from the total cornea (R=0.54, P<0.001); however, no correlation was found between cSPK score and ocular forward light scattering (R=0.01, P=0.932).
  
  
  CONCLUSIONS
  Ocular forward light scattering and corneal backward light scattering from the anterior cornea were greater in dry eyes than in normal eyes. Increased corneal backward light scattering in dry eye at least partially results from cSPK overlying the optical zone.
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Koh
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Maeda
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan Research and Development Division, Rohto Pharmaceutical Co., Ltd., Kyoto, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Ikeda
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Sanae
authors.initials: S
authors.lastname: Asonuma
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Mitamura
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Oie
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Soma
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Motokazu
authors.initials: M
authors.lastname: Tsujikawa
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawasaki
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Nishida
mesh_terms: D016022:Case-Control Studies; D003315:Cornea / Q000473:pathology* / Q000503:physiopathology; D019781:Corneal Topography; D015352:Dry Eye Syndromes / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012542:Scattering, Radiation; D014792:Visual Acuity
keywords: dry eye; light scattering; superficial punctate keratopathy