title: Optic nerve head changes after short-term intraocular pressure elevation in acute primary angle-closure suspects.
abstract: OBJECTIVE
  To investigate changes in the optic nerve head morphology after acute intraocular pressure (IOP) elevation during a dark room prone provocative test (DRPPT).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Acute primary angle-closure (APAC) suspects underwent DRPPT.
  
  
  METHODS
  Study participants stayed in a dark room for 2 hours with the forehead placed on a desk. At baseline and within 5 minutes after DRPPT, tonometry and enhanced depth imaging by spectral-domain optical coherence tomography (SD OCT) were performed.
  
  
  METHODS
  Changes in 3-dimensional optic nerve head topography.
  
  
  RESULTS
  The study included 114 eyes of 65 participants with a mean age of 58.3±8.7 years and a mean IOP elevation of 10.1±10.9 mmHg during DRPPT. When all eyes were included, the mean value of most optic disc parameters did not change significantly, except for a decrease in the temporal minimal rim width (P = 0.005). By including only eyes with an IOP increase greater than 15 mmHg, the mean value of cup width (P = 0.001) and cup depth (P = 0.002) increased, whereas the lamina cribrosa (LC) thickness (P = 0.035), temporal minimal rim width (P = 0.001), and nasal minimal rim width (P < 0.001) decreased. The LC depth and Bruch's membrane opening (BMO) did not differ between the baseline and the end of DRPPT. An IOP increase was significantly associated with widening (P < 0.001; r = 0.46) and deepening (P < 0.001; r = 0.52) of the optic cup, thinning of the LC (P = 0.003; r = -0.35), temporal minimal rim width (P < 0.001; r = -0.34), and nasal minimal rim width (P < 0.001; r = -0.35).
  
  
  CONCLUSIONS
  Angle-closure suspect eyes showed a widening and deepening of the optic cup, decrease in neuroretinal rim width, and thinning of the LC after a darkness-induced IOP increase of >15 mmHg. The diameter of the BMO and position of the anterior LC surface remained unchanged. This suggests that a short-term IOP increase leads to a condensation of neuroretinal rim, prelaminar tissue, and LC, without major changes in the optic disc size and position of the anterior LC surface.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Liu
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Jian Dong
authors.initials: JD
authors.lastname: Chen
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China; Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Seegartenklinik Heidelberg, Germany.
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China. Electronic address: yaxingw@gmail.com.
authors.forename: Ya Xing
authors.initials: YX
authors.lastname: Wang
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry; D015331:Cohort Studies; D003623:Dark Adaptation; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D011446:Prospective Studies; D041623:Tomography, Optical Coherence