September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Impact of Natural Blind Spot Location on Perimetry
Author Affiliations & Notes
  • Mengyu Wang
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
    Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
  • Louis R Pasquale
    Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
  • Lucy Q Shen
    Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
  • Michael V Boland
    Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
  • Sarah Wellik
    Bascom Palmer Eye Institute, Miami, Florida, United States
  • C Gustavo De Moraes
    Edward S. Harkness Eye Institute, Columbia University Medical Center, New York City, New York, United States
  • Jonathan S Myers
    Wills Eye Hospital, Philadelphia, Pennsylvania, United States
  • Peter Bex
    Phycology, Northeastern University, Boston, Massachusetts, United States
  • Tobias Elze
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
    Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
  • Footnotes
    Commercial Relationships   Mengyu Wang, None; Louis Pasquale, None; Lucy Shen, None; Michael Boland, Carl Zeiss Meditec (F); Sarah Wellik, None; C Gustavo De Moraes, None; Jonathan Myers, Haag Streit (F); Peter Bex, United States PCT/US2014/052414 (P); Tobias Elze, United States PCT/US2014/052414 (P)
  • Footnotes
    Support  Lions Foundation Grant 2015;NIH grant R01 EY018664; Harvard Glaucoma Center of Excellence; American Glaucoma Society Young Physician Scientist Grant Award
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 630. doi:
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      Mengyu Wang, Louis R Pasquale, Lucy Q Shen, Michael V Boland, Sarah Wellik, C Gustavo De Moraes, Jonathan S Myers, Peter Bex, Tobias Elze; Impact of Natural Blind Spot Location on Perimetry. Invest. Ophthalmol. Vis. Sci. 2016;57(12):630.

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

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Abstract

Purpose : The natural blind spot location (NBSL) measured prior to the visual field (VF) by perimeters like the Humphrey Field Analyzer (HFA) is not considered for calculations of diagnostic parameters like pattern deviations (PD). We study the impact of NBSL on PD values of patients from 5 glaucoma practices.

Methods : The most recent reliable HFA VFs (fixation loss≤33%, false negative/positive rates≤20%, SITA Standard 24-2) were selected from each eye. To minimize possible effects of potentially existing glaucomatous VF loss, only VFs with mean deviations ≥-1dB, pattern standard deviations that are not flagged as abnormal and glaucoma hemifield tests within normal limits were included. As the HFA returns a NBSL of (15,-1) degree by default even if no blind spot test was performed, VFs with this NBSL were excluded as well. Distributions of NBSL frequency and spherical equivalent (SE) of refractive error for each NBSL were determined. In addition we compared PD values larger and smaller than the median distance as well as positive and negative angle between NBSL and fixation by t-tests.

Results : 12,751VFs were selected for data analysis. Fig. 1a illustrates the spatial distribution of NBSL relative to fixation. Average SE decreases with increasing distance from fixation (Fig. 1b), as expected by the well documented negative correlation between SE and ocular axial length. Fig. 2 shows the PD value difference effects with respect to NBSL relative to fixation (all eyes in right eye format). For NBSL distances larger than median distance 14.32, average PD values decrease (red) in the upper central (average difference for significant points (ADSP): -0.16 dB) and increase (blue) in the lower nasal VF region (ADSP: 0.13 dB). For angles in the direction of the upper hemifield relative to the median angle -8.13°, PD values decrease in lower nasal (ADSP: -0.10 dB) and increase in upper temporal VF areas (ADSP: 0.14 dB).

Conclusions : As effects of optic disc location relative to fovea on retinal nerve fiber trajectories were discussed in literatures, we demonstrate that the functional equivalent, NBSL relative to fixation, has a systematic effect on the spatial distribution of light sensitivity. NBSL distance and angle relative to fixation independently affect the distribution of PD values. As PD values are important diagnostic parameters for diseases like glaucoma, taking NBSL into consideration might improve the diagnosis of functional vision loss.

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

 

 

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