title: The ocular surface side effects of an anti-psychotic drug, clozapine.
abstract: OBJECTIVE
  The purpose of this study is to investigate the effects of long-term clozapine usage on tear film stability and corneal topographic parameters.
  
  
  METHODS
  The study was conducted between March 2014 and November 2014. Thirty patients who were diagnosed of schizophrenia and have been under clozapine treatment for 2.73 ± 0.73 years (range 2-4 years) were involved in this study (group 1). Thirty healthy subjects (group 2) who have statistically similar demographic features compared with the group 1, were involved as a control group. Full ophthalmologic examination with biomicroscopy and indirect ophthalmoscopy was applied. Corneal topographic parameters were measured using the Pentacam HR and Schirmer test was done. Statistical analysis of the subjects was evaluated by using SPSS (for Windows version 16.0; SPSS Inc., Chicago, IL) program.
  
  
  RESULTS
  K1 value was measured as 43.39 ± 0.17 D (43-43.50 D) and K2 value was measured as 43.39 ± 0.06 D (43.30-43.50 D) in groups 1 and 2, respectively. In groups 1 and 2, K2 values were noted as 43.86 ± 0.27 D (43.50-44.50 D) and 43.72 ± 0.18 D (43.50-44.00 D), respectively. Central corneal thickness was found to be 523.93 ± 15.66 µm (495-554 µm) and 550.13 ± 1.03 µm (520-580 µm) in groups 1 and 2, respectively. Corneal apex thickness was 525.86 ± 15.75 µm (497-556 µm) in group 1 and 551.60 ± 14.99 µm (521-581 µm) in group 2. The corneal thickness of thinnest location was 520.93 ± 15.60 µm (492-551 µm) and 548.06 ± 15.17 µm (518-578 µm) in groups 1 and 2, respectively. Corneal volume was determined as 58.13 ± 3.46 mm(3) (52-64 mm(3)) in group 1 and 60.73 ± 3.76 mm(3) (54-66 mm(3)) in group 2. The Schirmer test showed thickness of 3.33 ± 0.72 mm (2-4 mm) and 13.60 ± 1.59 mm (11-16 mm) in groups 1 and 2, respectively. The mean fluorescein break-up time was 5.40 ± 1.50 s (3-8 s) and 12.46 ± 1.40 s (10-14 s) in groups 1 and 2, respectively. There was a statistically significant difference in the Schirmer test, fluorescein break-up time, central corneal thickness, corneal apex, and the thinnest corneal location thickness between the two groups.
  
  
  CONCLUSIONS
  Clozapine may induce dry eye syndrome and thus may lead to morphological alterations in corneal parameters through its anticholinergic and antidopaminergic activities. Because of these corneal alterations, one should be aware of evaluating patients having diseases like glaucoma or preoperative selection of corneal refractive surgery candidates.
authors: a Department of Ophthalmology , Erzurum Regional Training and Research Hospital , Erzurum , Turkey and.
authors: Erdinç
authors: E
authors: Ceylan
authors: b Department of Ophthalmology , Istanbul Faculty of Medicine , Istanbul , Turkey.
authors: Muhammet Derda
authors: MD
authors: Ozer
authors: b Department of Ophthalmology , Istanbul Faculty of Medicine , Istanbul , Turkey.
authors: Yusuf Cem
authors: YC
authors: Yilmaz
authors: a Department of Ophthalmology , Erzurum Regional Training and Research Hospital , Erzurum , Turkey and.
authors: Baki
authors: B
authors: Kartal
authors: b Department of Ophthalmology , Istanbul Faculty of Medicine , Istanbul , Turkey.
authors: Dilbade
authors: D
authors: Yildiz Ekinci
authors: a Department of Ophthalmology , Erzurum Regional Training and Research Hospital , Erzurum , Turkey and.
authors: Emine
authors: E
authors: Çinici
authors: b Department of Ophthalmology , Istanbul Faculty of Medicine , Istanbul , Turkey.
authors: Nihan
authors: N
authors: Aksu Ceylan
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D003315:Cornea / Q000187:drug effects / Q000473:pathology; D019781:Corneal Topography; D015352:Dry Eye Syndromes / Q000139:chemically induced* / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D012559:Schizophrenia / Q000188:drug therapy / Q000473:pathology
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine
keywords: Clozapine; Pentacam HR; corneal parameters; dry eye syndrome