September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Shape Changes of the Anterior Lamina Cribrosa in Healthy and Glaucoma Eyes following Acute Intraocular Pressure Elevations
Author Affiliations & Notes
  • Tin Aung Tun
    Singapore Eye Research Institute, Singapore, Singapore
  • Owen Png
    Duke-NUS Graduate Medical School, Singapore, Singapore
  • Baskaran Mani
    Singapore Eye Research Institute, Singapore, Singapore
    Duke-NUS Graduate Medical School, Singapore, Singapore
  • Sourabh Sharma
    Singapore Eye Research Institute, Singapore, Singapore
  • Hla Myint Htoon
    Singapore Eye Research Institute, Singapore, Singapore
    Duke-NUS Graduate Medical School, Singapore, Singapore
  • Sri Gowtham Thakku
    Singapore Eye Research Institute, Singapore, Singapore
  • Ching-Yu Cheng
    Singapore Eye Research Institute, Singapore, Singapore
    Duke-NUS Graduate Medical School, Singapore, Singapore
  • Nicholas G Strouthidis
    NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
    Singapore Eye Research Institute, Singapore, Singapore
  • Tin Aung
    Singapore Eye Research Institute, Singapore, Singapore
    Duke-NUS Graduate Medical School, Singapore, Singapore
  • Michael J A Girard
    Singapore Eye Research Institute, Singapore, Singapore
  • Footnotes
    Commercial Relationships   Tin Tun, None; Owen Png, None; Baskaran Mani, None; Sourabh Sharma, None; Hla Htoon, None; Sri Gowtham Thakku, None; Ching-Yu Cheng, None; Nicholas Strouthidis, None; Tin Aung, None; Michael Girard, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 3556. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Tin Aung Tun, Owen Png, Baskaran Mani, Sourabh Sharma, Hla Myint Htoon, Sri Gowtham Thakku, Ching-Yu Cheng, Nicholas G Strouthidis, Tin Aung, Michael J A Girard; Shape Changes of the Anterior Lamina Cribrosa in Healthy and Glaucoma Eyes following Acute Intraocular Pressure Elevations. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3556.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : To estimate and compare changes in anterior lamina cribrosa (LC) morphology in normal and glaucoma eyes following acute elevations in intraocular pressure (IOP)

Methods : One optic nerve head (ONH) of 18 ocular hypertension (OHT), 21 primary open angle glaucoma (POAG), 33 chronic primary angle closure glaucoma (PACG) and 31 normal subjects was imaged using spectral-domain optical coherence tomography (OCT; Spectralis, Heidelberg Engineering, Germany). IOP was raised twice by gently applying a force (0.64 N then 0.9 N) to the anterior sclera (through the lower eye lid) using an ophthalmo-dynamometer (spring-loaded indenter). After each IOP increment, IOP was held constant, measured with a TonoPen, and each ONH was rescanned with OCT. In each OCT volume, the anterior LC was enhanced with adaptive compensation, manually delineated, and its global shape index (GSI) calculated (Thakku et al., IOVS. 2015 Jun;56(6):3604-14). GSI is a single index that provides a global measure of LC shape and that varies from -1 (posteriorly curved LC) to +1 (anteriorly curved LC). Wilcoxon signed-Rank tests and Linear Mixed Models were used to assess the differences in GSI across groups.

Results : Of the 103 subjects, 51.5% were males with a mean age of 64.5±7.1 years. At baseline, IOP was 17.5±3.4 mmHg and was increased to 37.6±5.9, then 46.2±6.1 mmHg. When considering the first IOP increment, the GSI median was significantly smaller than that at baseline in normal (Z=2.73, P=0.006) and in glaucoma subjects (Z=2.45, P=0.014), but not in OHT subjects (Z=77, P=0.734). For the second IOP increment, the GSI median was significantly smaller than that at baseline in normal (Z=3.2, P=0.001) and in OHT (Z=32, P=0.018). (Figure1) After adjusting for age, gender and baseline IOP, mixed model analysis showed that the LC of PACG eyes was significantly more posteriorly curved than that of normal subjects (Estimated Mean difference -0.15, 95% confidence interval = -0.299, -0.001, P=0.047), but this was not found for other diagnoses.

Conclusions : We demonstrated that acute IOP elevations altered anterior LC shape in living human eyes. The connective tissues of OHT eyes might be stiffer than those from all other groups because the LC of OHT eyes only deformed at high IOP. The LC of PACG eyes was more posteriorly curved following acute elevations in IOP when compared to that of normal eyes.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×