April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
The Association Between Normal Optic Nerve Cupping , Normal Visual Fields and Marijuana Use
Author Affiliations & Notes
  • Edwin R Swann
    Duke Raleigh Hospital, Duke Health Systems, Raleigh, NC
  • Footnotes
    Commercial Relationships Edwin Swann, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 567. doi:
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      Edwin R Swann; The Association Between Normal Optic Nerve Cupping , Normal Visual Fields and Marijuana Use. Invest. Ophthalmol. Vis. Sci. 2014;55(13):567.

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

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Abstract
 
Purpose
 

The purpose of this study was to test for the association between normal optic nerve cupping, normal visual fields (VF) and a history of having smoked marijuana.The null hypothesis was that there is no difference in the odds of having a vertical cup disc ratio (C/D ratio) of less than 0.5, or normal VF in subjects who reports a history of having smoked marijuana compared those who had not smoked it.

 
Methods
 

The 2005-2008 NHANES data were imported into Stata/IC version10.0 (StataCorp LP, College Station, Texas). Variables analyzed were: "ever smoke marijuana", " the vertical C/D ratio" of each eye, race/ethnicit, gender, and age. Another variable examined was normal Humphrey Matrix VF as defined by an NHANES algorithm.The variable vertical C/D ratio was use to create a dichotomous variable "C/D ratio < 0.5". The variables for ever smoke marijuana, C/D ratio < 0.5 and normal VF were used to create dichotomous variables to represent those variables for each subject instead of for each eye. The logistic regression models for the dependent variables C/D ratio < 0.5 and normal VF were created using a backward elimination process. The model with C/D ratio < 0.5 as a dependent variable had remaining variables ever smoked marijuana and gender as independent variables. The model with normal VF as the dependent variable had a remaining variable of ever smoked marijuana. Permission to allow use of de-identified data from the NHANES in other studies was obtained from subjects at the time of their enrollment.

 
Results
 

The adjusted odds ratio of subjects with a vertical C/D ratio < 0.5 was 1.26, 95% CL (1.03 - 1.58) with a "P" value = 0.037. The odds ratio of subjects with a normal VF who had smoked marijuana compared to those who had not was 1.4, 95% CL (0.91 - 2.16) with a "P" value = 0.119 .

 
Conclusions
 

This study shows a statistically significant increase in the odds of subjects with C/D ratios<0.5 having a history of having smoked marijuana. There was a lack of statistical significance for the odds of having a normal VF test in subjects who reported having smoked marijuana possibly related to the smaller sample size. These results suggest that the use of marijuana may have a protective influence on the optic nerve. Croxford (2003) has reported that cannabinoids "may be potent neuroprotective agents." Further studies could reveal that marijuana has neuroprotective properties .

     
Keywords: 615 neuroprotection • 627 optic disc • 758 visual fields  
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