Effects of Smoking on Vision

Several studies have been done which show that smoking can lead to vision problems later in life.

For example, evidence suggests that the risk of developing age-related macular degeneration (AMD) at least doubles for persons who are long-term smokers. AMD is a major cause of irreversible vision loss in the Western world, especially among the elderly [1].

“Smokers are at a greater risk of losing their vision to age-related macular degeneration, according to two articles published in The Journal of the American Medical Association in October 1996.

In one study, researchers found that women who were current and past smokers had a significantly greater risk of developing age-related macular degeneration than women who had never smoked. In the second study, men who smoked one pack or more of cigarettes daily had a two to three-fold increased risk of macular degeneration compared with those who had never smoked” [2].

It was found that even woman [3] and men [4] who had stopped smoking fifteen and twenty years prior to the end of the studies had a greater risk of age-related macular degeneration than those who never smoked.

Poor blood flow to the retina and low amounts of antioxidants present in the bloodstream are believed to be contributing factors to age-related macular degeneration. Smoking ranks as a risk factor because it can cause both of these [3].

The identification of smoking as a risk factor of AMD is important because smoking is one area in which a person can take control.

“The identification of smoking as a risk factor can lead to early intervention. Such

intervention may lessen the visual loss from this disease, which has limited medical treatment options” [5].

Smoking has also been linked to the development of cataracts. Researchers of several studies have concluded that smoking is associated with a higher risk of nuclear [6] and posterior subcapsular cataracts [7].

One study examined the effects of smoking on the lens prior to cataract development. The “data indicated that smoking is directly related to age-related increases in lens optical density throughout life and that these increase persist even after smoking cessation” [8]. This appears to support other studies which indicate that smoking increases the risk of age-related cataracts.

The pupil diameter changes as the eye adjusts from darkness to light. Two studies were performed to determine the effects of smoking on the pupil. Results of the two studies were contradictory. One study found that no changes occurred the in pupil diameter of tobacco smokers [9]. The other study found that the subjects who smoked one tobacco cigarette had greater pupillary constriction than those who smoked a placebo cigarette [10].

Ways in which nicotine may effect task performance are being tested. One study examined “how nicotine influences shifts of visuo spatial attention in casual smokers” [11]. The findings suggest that nicotine may decrease one’s attention span; therefore, increasing the ease in which one breaks eye gaze from a task.

Another aspect of vision is color perception. Investigators of one study discovered that smokers who consume more than 20 cigarettes per day may have color perception deficits [12].

References:

1. Epidemiology of age-related macular degeneration. Hawkins BS; Klein R; West SK MOLECULAR VISION vol. 5 (1999 NOv 3):26

For more than two decades, researchers have sought to identify "risk factors" for age-related macular degeneration (AMD), a major cause of irreversible vision loss in the Western world, particualary in the elderly. The available evidence supports at least a doubling of risk of late AMD associated with long-term smoking, a factor that is under the control of the individual.

2. http://www.slsbvi.org/info/resear.htm

3. http://www.sciencenews.org/sn_arch/10_12_96/fob2.htm

4. http://health.phillynews.com/encyclopedia/archive/smoking/smoking.008.asp

5. Cigarette smoking and age-related macular degeneration. Chan D OPTOMETRY AND VISION SCIENCE. vol. 75, no. 7 (1998 Jul): 476-84.

BACKGROUND: Age-related macular degeneration (ARMD) is one of the leading causes of severe visual impairment among older Americans. Several hypotheses have been proposed regarding the pathogenesis of ARMD. The possible association of cigarette smoking and ARMD remains controversial. CONCLUSIONS: The identification of smoking as a risk factor can lead to early intervention. Such intervention may lessen visual loss from this disease, which has limited medical treatment options.

6. Incident cataract after a five-year interval and lifestyle factors: the Beaver Dam eye study. Klein BE; Klein RE; Lee KE OPHTHALMIC EPIDEMIOLOGY. vol. 6, no. 4 (1999 Dec): 247-55.

SPECIFIC OBJECTIVES: To examine the relationships of cigarette smoking, alcohol, and caffeine intakes to incidence of age-related cataracts five years later. CONCLUSIONS: Cigarette smoking and alcohol consumption were associated with modestly increased risks of incident nuclear cataract over a five-year interval.

7. Alcohol, smoking, and cataracts: the Blue Mountains Eye Study. Cumming RG; Mitchell P ARCHIVES OF OPHTHALMOLOGY. vol. 115, no. 10 (1997 Oct): 1296-303.

OBJECTIVE: To investigate the associations between alcohol consumption, tobacco smoking, and cataract. CONCLUSIONS: Consistent with other studies, smoking was associated with a higher prevalence of nuclear and posterior subcapsular cataracts. The only adverse effect of alcohol was among smokers: people who smoked and drank heavily had an increased prevalence of nuclear cataract.

8. Smoking and lens optical density. Hammond BR; Wooten BR; Nanez JE; Wenzel AJ OPHTHALMIC AND PHYSIOLOGICAL OPTICS. vol. 19, no. 4 (1999 Jul): 300-5.

Epidemiological evidence indicates that smoking increases the risk of age-related cataract. No information is currently available, however, on the effects of smoking on the lens prior to cataract development. In this study, we relate smoking behavior to lens optical density (OD) in younger individuals without frank cataract. Our data indicate that smoking is directly related to age-related increases in lens OD throughout life and that these increases persist even after smoking cessation.

9. Effects of tobacco smoking on human ocular smooth pursuit [published erratum appears in Clin Pharmacol Ther 1997 Jun;61(6):627] Domino EF; Ni LS; Zhang H CLINICAL PHARMACOLOGY AND THERAPEUTICS. vol. 61, no. 3 (1997 Mar): 349-59.

OBJECTIVE: Test the hypothesis that nicotine-induced nystagmus results in reduced ocular smooth performance and pupil diameter in tobacco smokers. CONCLUSIONS: Contrary to the hypothesis, tobacco smokers had a very small but significant improvement in left eye pursuit but no change in pupil diameter.

10. Effects of tobacco smoking on the human pupil. Lie TC; Domino EF INTERNATIONAL JOURNAL OF CLINICAL PHARMACOLOGY AND THERAPEUTICS. vol. 37, no. 4 (1999 Apr): 184-8.

OBJECTIVE: Determine the effects of tobacco cigarette or sham placebo-smoking on pupil diameter. CONCLUSIONS: Shortly after smoking one tobacco cigarette, pupillary constriction was greater than after sham-smoking.

11. The effects of nicotine on spatial and non-spatial expectancies in a covert orienting task. Murphy FC; Klein RM NEUROPSYCHOLOGIA. vol. 36, no. 11 (1998 Nov): 1103-14.

The present study examined how nicotine influences shifts of visuo spatial attention in casual smokers at each of three delays after smoking one cigarette: immediately, 1 h and 24 h. The performance decrement obtained when the target appeared at an uncued location was smallest in sessions run immediately after smoking (when nicotine levels were highest), suggesting that nicotine may increase the ease with which attention can be disengaged from a cued location.

12. Colour vision disturbances in chronic smokers. Erb C; Nicaeus T; Adler M; Isensee J; Zrenner E; Thiel HJ GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY. vol. 237, no. 5 (1999 May): 377-80.

PURPOSE: The aim of the present study was to test the influence of smoking on colour perception. CONCLUSION: Otherwise healthy smokers with a cigarette consumption of less than 20 cigarettes per day do not show any disturbances in colour vision. Smokers who consume more than 20 cigarettes per day may suffer colour vision defects as a result.