While the effects of alcohol intake on organs such as the liver and brain are well-known, the ocular impact of imbibing is less commonly understood by patients. But excessive consumption of alcohol can lead to a variety of adverse effects on the eye, ranging from minor and reversible to debilitating and permanent.1 The Centers for Disease Control and Prevention (CDC) defines excessive drinking as 4 or more drinks on a single occasion for women and 5 or more drinks on a single occasion for men, or a weekly total of 8 or more drinks for women and 15 or more drinks for men.2

“In the short term, alcohol use causes dryness and redness of the eye due to vasodilation on the ocular surface,” said Esen K. Akpek, MD, the Bendann Professor of Ophthalmology at the Johns Hopkins University School of Medicine in Baltimore and a clinician at the Wilmer Eye Institute at Johns Hopkins Hospital and Johns Hopkins Bayview Medical Center. With chronic use, nutritional deficiencies can develop and result in more serious problems. For example, vitamin A deficiency can lead to corneal complications and blindness, and vitamin B1 deficiency can cause ocular motor dysfunction due to Wernicke’s encephalopathy.3,4

Additionally, chronic “alcohol consumption can lead to deficiencies in vitamin B12 and folate, and these deficiencies can cause a toxic optic neuropathy which results in chronic permanent vision loss,” explained Victoria L. Tseng, MD, PhD, assistant professor in the department of ophthalmology at the University of California, Los Angeles and practitioner in the Doheny and Stein Eye Institutes at UCLA. 


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“Studies have also suggested that heavy alcohol consumption may be associated with increased risk of cataract formation, which may be related to oxidative stress, though pathophysiologic mechanisms need to be examined in further detail,”a 2021 study says.5

Other research has indicated a link between chronic alcohol intake and chronic eye diseases including age-related macular degeneration, glaucoma, and diabetic retinopathy, although these findings have been mixed overall.5

Detecting Drinking’s Damage

Clinicians may use various examination and imaging methods to detect damage to the optic nerve that can result from excessive alcohol intake. “On exam, patients could have decreased visual acuity, loss of color vision, a relative afferent pupillary defect if one nerve is more damaged than the other, and pallor of the optic nerve on fundus exam,” Dr Tseng said. With ancillary testing, perimetric testing may show characteristic changes such as a cecocentral scotoma, and ocular coherence tomography may reveal decreased nerve fiber layer thickness, she explained.

“Other chronic eye conditions which may be associated with alcohol consumption such as cataract, age-related macular degeneration, and glaucoma can be initially detected with slit lamp and fundus examination and investigated further with ancillary testing modalities specific to each condition,” she stated.

In addition to performing a detailed history and exam, if physicians suspect alcohol use disorder, a more detailed social history including questions about alcohol use may be appropriate, according to Dr Tseng. Alcohol-specific screening tools such as the CAGE questionnaire may be used for this purpose.6 That guideline, developed in the 1970s, offers clinicians a simple, 4-point yes-or-no questionnaire. Patients who answer in the affirmative for 2 of these questions “should create a high index of suspicion,” while positive responses to all 4 is “pathognomonic for alcoholism,” according to a publication.6 

The 4 questions are:

1. Have you ever felt you ought to Cut down on your drinking?

2. Have people Annoyed you by criticizing your drinking?

3. Have you ever felt bad or Guilty about your drinking?

4. Do you ever have an Eye opener drink first thing in the morning to steady your

nerves or get rid of a hangover?

Ocular Associations of Alcohol Addiction 

For those with chronic alcohol consumption, clinicians should discuss the harms of such use and the need to abstain from drinking to prevent further damage. “While such a discussion is admittedly challenging, doing so with a multidisciplinary approach involving primary care, social work, nutrition, and neurology can help,” said Avnish Deobhakta, MD, assistant professor of ophthalmology at the Icahn School of Medicine at Mount Sinai and vitreoretinal surgeon at the New York Eye and Ear Infirmary of Mount Sinai. 

Ocular Surface Disease. As mentioned, alcohol use, chronic or acute, can cause ocular surface dryness. On a strictly biological basis, drinking alcohol can induce transient dry eye syndrome in healthy individuals, according to a 2012 study. That research found that even mild alcohol use is associated with the detection of ethanol in tears, which can  induce hyperosmolarity and shorten tear film break-up time (TBUT).7 It may even trigger the development of chronic ocular surface disease, the study says.7

In fact, alcohol is a diuretic, which should be expected to create dryness. However, a 2021 study shows that, while that’s the case for women, it’s not always the case for men. Alcohol use significantly increases symptomatic dry eye risk in women (odds ratio [OR] 1.095, 95% CI, 1.045-1.148), but not in men (OR 0.988, 95%CI 0.900–1.084), according to a study.8 That study, based in Scandanavia, suggests alcohol use has such sex-specific effects on several outcomes of dry eye disease, including symptomatic dry eye, highly symptomatic dry eye, clinical diagnosis, and Women’s Healthy Study (WHS) definition dry eye. But men experienced a potential protective effect against dry eye, although researchers say this is mild at best, and should “be interpreted with caution, as alcohol’s other health effects might be of greater clinical significance.”8    

“Patients with dry eye should always be asked about drinking, although vitamin A deficiency can also affect people who follow a vegan diet and individuals who have had GI issues or surgeries such as weight-loss surgery,” notes Dr Akpek.  

Other research says that alcohol-induced peripheral neuropathy may provide false reassurance that dry eye symptoms are low among heavy drinkers.9 In fact, a meta analysis shows that alcohol consumption is a significant risk factor for dry eye and that severity can be linked with the amount that an individual drinks. Those who drink heavily can develop peripheral neuropathy, which in turn may decrease corneal sensitivity, masking the real severity of dry eye. Researchers behind that study say their findings “indicate that controlling alcohol consumption may help to reduce [dry eye] prevalence.”9

Sight-Threatening Diseases. Alcohol also plays a role in conditions that affect ocular function, including cataract development, the onset of age-related macular degeneration, and glaucoma, to name a few. 

A 2015 study shows that heavy alcohol consumption can increase the risk of cataracts  significantly, although moderate consumption may be protective.10 Another reason, perhaps, for ophthalmologists and optometrists to gather information on a patient’s history with alcohol. An analysis of the Blue Mountains Eye Study also demonstrates a “U-shaped association of alcohol consumption with the long-term risk of cataract surgery” with moderate consumption (1 to 2 standard drinks per day) being associated with a 50% lower cataract surgery incidence, compared with either abstinence or heavy alcohol consumption.11

Patients with or at risk for age-related macular degeneration (AMD) walk a similar tightrope. In moderation, alcohol can decrease platelet aggregation, lower serum fibrinogen, C-reactive protein levels, and increase high-density lipoprotein cholesterol levels, all of which may protect against the development of AMD. But those who already have an AMD diagnosis may put themselves at greater risk by drinking alcohol, due to its neurotoxicity and potential to cause oxidative stress on the retina. These qualities have led researchers to uncover alcohol’s causal association with geographic atrophy in patients with AMD.12

While no link has been established between alcohol consumption and glaucoma directly, research does show that excessive alcohol use (≥8 standard drinks per week for women, ≥15 for men) can cause thinning of the ganglion cell inner plexion layer, raising the possibility that drinking is linked to glaucoma severity.13 

Systemic Disease. For patients with systemic diseases, alcohol use is often risky, even in moderate amounts. Take, for example, those with type 2 diabetes. Alcohol can cause an acute elevation of the blood sugar level.14 For patients with diabetic retinopathy, even moderate alcohol consumption can potentially result in deterioration of visual acuity, research shows.15

Although heavy alcohol use doesn’t cause optic neuropathy on its own, it does create the conditions for it by depleting the body of nutrients such as thiamine, folic acid, cyanocobalamin.16 Optic neuropathy can impair color vision, cause an abnormal papillary response, or even lead to vision loss.17 By the time it’s diagnosed, it is often at a stage when full visual recovery is no longer an option.16

The most severe effects of alcohol dependency can induce permanent retinal damage, central serous chorioretinopathy, retinal detachment, and even vision loss.18 Alcohol liver disease can lead to cirrhosis, which in late stages, can be accompanied by jaundice and yellowed eyes.18 

Alcohol Secession, Ophthalmic Follow Up

Certain alcohol-induced ocular effects may be amenable to treatment, while other effects may result in permanent damage. “Ocular surface changes due to vitamin A deficiency could be reversible unless corneal opacity has already occurred,” Dr Akpek noted as an example. 

Cessation of alcohol use may lead to resolution of some of the visual changes resulting from optic neuropathy, according to Dr Deobhakta. For patients showing obvious signs of damage to the optic nerve, he recommends consultation with a neurologist and neuro-ophthalmologist. “In addition, one should strongly consider either referral to a primary care physician or, if that is not possible, a laboratory investigation for serum B12 or folate levels,” he advised. 

Supplementation with B12 and folate are often indicated for these patients, Dr Deobhakta explained. Referral to a nutrition specialist may be needed to advise patients on required dietary changes. “Identifying and addressing the nutritional status of the patient — which is often a neglected part of the medical history — may prevent long-term damage of neural structures both in the eye and in the rest of the central nervous system if it can be countered quickly,” he said. 

Patients with retinal changes should be treated or referred to a retina subspecialist for further evaluation. For patients with chronic alcohol use presenting with cataract, refractive correction or surgery may be helpful, while ocular vitamin supplementation and intravitreal injections may improve macular degeneration, Dr Deobhakta explained. These cases and those involving retinal changes may warrant referral to an ophthalmic subspecialist.

While chronic and excessive alcohol use can lead to severe ocular consequences, early detection and treatment can reverse or limit the damage in many cases. “Outcomes could be optimized with cessation of alcohol use and optimization of systemic health in conjunction with the primary care provider and other members of the multidisciplinary patient care team,” Dr Tseng stated.

References

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  2. Centers for Disease Control and Prevention. Alcohol use and your health. Updated April 14, 2022. Accessed June 13, 2022. 
  3. Khoo HE, Ng HS, Yap WS, Goh HJH, Yim HS. Nutrients for prevention of macular degeneration and eye-related diseases. Antioxidants (Basel). 2019;8(4):85. doi:10.3390/antiox8040085
  4. Isen DR, Kline LB. Neuro-ophthalmic manifestations of Wernicke encephalopathy. Eye Brain. 2020;12:49-60. doi:10.2147/EB.S234078
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  6. Ewing JA. Detecting alcoholism the CAGE questionnaire. JAMA. 1984;252(14):1905-1907. doi:10.1001/jama.1984.03350140051025 
  7. Kim JH, Kim JH, Nam WH, et al. Oral alcohol administration disturbs tear film and ocular surface. Ophthalmol. 2021;119(5):965-971. doi:10.1016/j.ophtha.2011.11.015
  8. Magno MS, Mathias TD, Morthenac K, et al. The relationship between alcohol consumption and dry eye. Ocul Surf. 2021; 2.1(7):87-95. doi:10.1016/j.jtos.2021.05.005
  9. You YS, Qu NB, Yu XN. Alcohol consumption and dry eye syndrome: a Meta-analysis. Int J Ophthalmol. 2016;9(10):1487–1492. doi:10.18240/ijo.2016.10.20
  10. Gong Y, Feng K, Yan N, Xu Y, Pan CW. Different amounts of alcohol consumption and cataract: a meta-analysis. Optom Vis Sci. 2015;92(4):471-9. doi:10.1097/OPX.0000000000000558.
  11. Kanthan GL, Mitchell P, Burlutsky G, Wang JJ. Alcohol consumption and the long-term incidence of cataract and cataract surgery: the Blue Mountains Eye Study. Am J Ophthalmol. 2010;150(3):434-440.e1. doi:10.1016/j.ajo.2010.04.020
  12. Su X, Wong TY. Revisiting the alcohol consumption association with age-related macular degeneration. What should we tell patients in 2021? JAMA Ophthalmol. 2021;139(12):1307-1308. doi:10.1001/jamaophthalmol.2021.4602
  13. Han YS, Kim YW, Kim YJ, Park KH, Jeoung JW. Alcohol consumption is associated with glaucoma severity regardless of ALDH2 polymorphism. Sci Reports. 2020;10:17422.
  14. Leggio L, Ray L, Kenna GA, Swift RM. Blood glucose level, alcohol heavy drinking and alcohol craving during treatment for alcohol dependence: results from the combined pharmacotherapies and behavioral interventions for alcohol dependence (COMBINE) study. Alcohol Clin Exp Res. 2009;33(9):1539–1544. doi:10.1111/j.1530-0277.2009.00982.x
  15. Lee CC, Stolk RP, Adler AI, et al, on behalf of the AdRem project team and ADVANCE management committee. Association between alcohol consumption and diabetic retinopathy and visual acuity-the AdRem Study. Diabet Med. 2010;27(10):1130-7. doi:10.1111/j.1464-5491.2010.03080.x.
  16. Chiotoroiu SM, Noaghi M, Stefaniu GI, Secureanu FA, Purcarea VL, Zemba M. Tobacco-alcohol optic neuropathy – clinical challenges in diagnosis. J Med Life. 2014;7(4):472–476.
  17. Behbehani R. Clinical approach to optic neuropathies. Clin Ophthalmol. 2007;1(3):233–246.
  18. Hsu CC, Chen YH, Huang KH, et al. Evaluation of the relationship between central serous chorioretinopathy and liver cirrhosis: A nationwide, population-based study. J Chinese Med Association. 2021;84(6):655-663. doi:10.1097/JCMA.0000000000000533

This article originally appeared on Ophthalmology Advisor