Original Article
Frequency
of Cataract and its Association with Tobacco Use in Subjects of an Eye Camp
Saba Alkhairy, Farnaz Siddiqui, Mazhar-ul-Hassan, Arif Nayani
Pak J Ophthalmol 2019, Vol. 35, No. 2
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See end of article for authors affiliations
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.. Correspondence to: Dr. Saba Alkhairy MBBS, FCPS, (OPHTH) Assistant Professor DIMC, DUHS Email: saba.alkhairy1@gmail.com |
Purpose: To find the frequency of cataract
and to study the relationship between cataract development and tobacco use. Study Design: Cross sectional study. Place and Duration of Study: Single day eye camp at Dow
University Hospital Karachi in August 2016. Material and Methods: All patients presenting to the
camp were screened through standard eye examination including refraction and
fundoscopy. After dilatation of pupil these patients were examined with a
slit lamp by a consultant ophthalmologist for confirmation of the presence of
cataract and its type. Participants were then questioned regarding the type
of tobacco use and its duration and frequency with which it was consumed. Those
patients with a history of tobacco consumption for more than ten years were
included in the study. Results: A total of 550 patients presented
to the eye camp of which 120 (21.81%) subjects were found to have a cataract.
The mean age of the subjects was 58.02 ± 8.3 years. There were 67 (55.8%)
males and 53 (44.2%) females. Among the patients diagnosed with cataract 89 (74.2%)
had no history of tobacco usage while 31 (25.8%) gave a positive response
regarding tobacco consumption. In nonsmokers the most common cataract was
cortical where as in cigarette smokers
it was nuclear 8 (57.1%) and in users of smokeless tobacco it was posterior
subcapsular 5 (38.5%). There were no pseudophakic patients seen as almost all
came from remote areas where there was lack of surgical facility. Conclusion: Tobacco consumption has a strong
association with cataract development. Cigarette Smoking as well as chewing
smokeless tobacco should be curtailed or avoided altogether. Keywords: Cataract, tobacco, visual acuity. |
Cataract is one of the major causes of blindness worldwide
accounting for nearly half of all blindness globally1. According
to the World Health Organization (WHO), nearly 20 million people throughout the
world suffer from reduced vision, of 3/60 or less, due to cataract. These
figures are predicted to increase to 40 million by the next year. Although there are now various surgical
procedures for extraction of cataract and hence to improve vision, many people
continue to have poor vision from cataracts due to lack of awareness, poor
access to health care and operative facilities and high surgical expense2.
Epidemiologic studies imply that etiology of cataract is due to various factors
and that their occurrence is related to increase in age. One particular factor
suggested to be the cause of cataract development is injury to the lens by
oxygen free radicles3. Raw
tobacco products and tobacco smoke both contain several materials, including
nicotine, free radicals, and carbon monoxide, which can enhance the injury
caused by oxidation and have a significant role in the development of cataract4,5.
Tobacco use has emerged as a serious health challenge in Pakistan
that now stands among the top four countries of the world with rapid increase
in tobacco market6. The various forms used are chewed, sucked, or
applied to teeth or gums. Smokeless tobacco is sold as packets of strands and
is used alone or along with betel leaf, areca nut and lime.
As the country is currently suffering
from epidemic of Tobacco addiction therefore the rationale of the study was to
study the effects of Tobacco use in general and smoking in particular so as to
increase public awareness about its potential health hazards. Strict laws should be implemented to
actively ban advertisement and promotion of tobacco and tobacco related
products. The
objective of this study was to study the frequency of cataract and to determine
the association between tobacco consumption and cataract development.
MATERIAL
AND METHODS
A total of 550 adult patients visited
an eye camp which was held on a single day in August 2016.All these patients
underwent visual acuity assessment using a Topcon
KR-800PA Auto Refractor followed by a subjective test with Snellen chart
at 6 meters with standard illumination by two qualified optometrists. Illiterate
subjects were assessed using the E chart while literate subjects were tested
using the standard letters. Individuals including both males and females and
those aged more than 40 were analyzed further. They were dilated with
tropicamide 1% eye drops instilled every 10 minutes for 30 minutes .After full
dilatation the cataract if detected was graded with lens opacities classification
system. Cataract
was categorized as any LOCS III grading of ≥ 2
in either eye. Cortical, nuclear, and posterior sub capsular cataracts (PSC)
were defined as LOCS III ≥ 2.
Also
detailed examination was done of the cornea, the anterior segment, disc, macula
and remaining retina along with gonioscopy and tonometry to rule out other
causes of decreased vision. They were then questioned in detail by a single
person as most were illiterate and were not able to answer the questionnaire
themselves. The subjects were then divided into two groups: those who consumed
tobacco in any form and those who had no history of smoking, chewing tobacco or
its utilization. Those who were smokers or consumed tobacco in any form were
further inquired about the kind of tobacco (cigarette or smokeless tobacco) use
if any and the duration of usage in terms of quantity and years. All the data
gathered was entered into questionnaires and was analyzed statistically using IBM
SPSS version 21.
The results were presented as Mean ± SD
for Age, frequency and percentages for gender, tobacco use and type of
cataract. Statistical association was calculated between cataract type with
gender and tobacco use using chi-square test. A p-value of 0.05 or less was
considered statistically significant.
RESULTS
Amongst the total number of 550
patients presenting to the OPD those who fulfilled the criteria were found to be
120 subjects, who were analyzed. Table 01 describes the descriptive statistics
of all respondents. Mean ± standard deviation of age (58.02 ± 8.3 years).
Frequency and percentages of males were 67 (55.8%) and females were 53 (44.2%).
Persons who did not use any tobacco were higher i.e. 89 (74.2%). For Cataract
type PSC was found to be 36 (30%) followed by cortical 35 (29.2%) and others
respectively.
Table
1: Descriptive Statistics of
respondents.
|
Characteristics |
N = 120 (%) |
|
Age years (Mean ± SD) |
58.02 ±
8.3 |
|
Gender |
|
|
Male |
67
(55.8%) |
|
Female |
53
(44.2%) |
|
Tobacco
Use |
|
|
Nil |
89
(74.2%) |
|
Betel Nuts |
13
(10.8%) |
|
Cigarettes |
14
(11.7%) |
|
Others |
4
(3.3%) |
|
Cataract type |
|
|
PSC |
36
(30%) |
|
Cortical |
35 (29.2%) |
|
Nuclear Cataract |
24
(20%) |
|
Cortical + Nuclear |
12
(10%) |
|
Cortical + PSC |
13
(10.8%) |
Table 2 describes the association of
cataract type with gender and tobacco use. Amongst the 67 male patients the
occurrence of cortical cataract was higher 29.9% where proportions of cortical
with nuclear were
Table 2: Relationship of Cataract with Gender and Tobacco use.
|
Characteristics |
Cataract Type |
|||||||
|
PSC |
Cortical |
Nuclear Cataract |
Cortical + Nuclear |
Cortical + PSC |
Total |
P-Value |
||
|
Gender |
||||||||
|
Male |
19 (28.4%) |
20 (29.9%) |
13 (19.4%) |
5 (7.5%) |
10 (14.9%) |
67 |
0.8 |
|
|
Female |
17 (32.1%) |
15 (28.3%) |
11 (20.8%) |
7 (13.2%) |
3 (5.7%) |
53 |
||
|
Tobacco
use |
||||||||
|
Nil |
25 (28.1%) |
28 (31.5%) |
12 (13.5%) |
12 (13.5%) |
12 (13.5%) |
89 |
0.02*~ |
|
|
Betel
Nuts |
5 (38.5%) |
3 (23.1%) |
4 (30.8%) |
0 (0.0%) |
1 (7.7%) |
13 |
||
|
Cigarettes |
4 (28.6%) |
2 (14.3%) |
8 (57.1%) |
0 (0.0%) |
0 (0.0%) |
14 |
||
|
Others |
2 (50.0%) |
2 (50.0%) |
0 (0.0%) |
0 (0.0%) |
0 (0.0%) |
4 |
||
|
Significant
at 5% |
||||||||
|
~Cells
proportion > 20% |
||||||||
very less i.e. 7.5%. In females out of
53, 17 (32.1%) had PSC and only 5.7% had cortical with PSC. There was no
significant association found for gender (P-value = 0.8). A significant
association was found due to the tobacco and occurrence of different cataract
types (P-value = 0.02 < 0.05).
Fig 1: Association
between Tobacco and cataract Type.
DISCUSSION
Of all the causes leading to visual impairment all over the world,
cataract is at the top of the list7. In a study conducted on elderly
patients living in Taiwan the three most common causes of visual impairment
were found to be cataract (41.7%), seconded by myopic macular degeneration
(12.5%) and then age-related macular degeneration (10.4%)8. In
another study done in an elderly home in South India the most common causes of
visual impairment were due to avoidable causes
including cataract (57.1%) and uncorrected refractive errors (26.4%)9.
A global data on visual impairment concluded the number of people with visual
impairment worldwide in 2002 was more than 161 million and among them cataract
remained the most important and leading cause of visual disability10.
Smoking causes damage to the lens through
oxidation by reducing the inherent antioxidative ability of the lens by
depleting substances as such as vitamin C, vitamin E, and
β-carotene11.12. Another reason is that
certain substances of tobacco contain heavy metals, such as cadmium, lead, and
copper, which are directly harmful to
lens and can also lead to formation of cataract13,14.
In Southeast Asia, tobacco is consumed in various
ways, including cigarettes or bides (dried
tobacco rolled in paper or leaf), chewing khaini
(tobacco with slaked lime and aromatic spices), sutra (dried tobacco leaves for chewing), or pan masala (tobacco with betel leaf), sucking gutka (mixture of tobacco and molasses available in small sachets),
and inhaling of naswar (nasal
inhalation of tobacco powder)15. In our study we analyzed a total of
120 subjects of whom 89 were nonsmokers and 31 were smokers. Cigarette smoking
was the most common form of tobacco use observed in 14 subjects (11.7%),
followed by betel nut chewing with grounded tobacco which was noted to be 13 (10.8%)
subjects, while a category of others included 4 (3.3%) subjects. The others
represented a category who consumed tobacco in various smokeless forms of
tobacco as mentioned above. The most common type of cataract seen in nonsmokers
was cortical cataract while in those individuals who were cigarette smokers the
most common type was nuclear cataract and in users of smokeless tobacco such as
betel nut users it was posterior subcapsular cataract. This is consistent with
other studies such as a Meta analysis done by Juan le ET al16 and
various other studies conducted in different countries of the world such as Singapore,
India and Australia respectively17-20.
In our study there was no significant association
found in gender p = 0.8. Overall in all of 120 subjects cataract was found more
in males as opposed to females but that is because of the increased number of
male subjects presenting to the hospital. The most common cataract found in
females was posterior subcapsular which was seen in 17 (32.1%) while the most
common cataract found in males was cortical that was seen in 20 (29.9%). This
conflicts with studies which have concluded that most common cataract found in
women is nuclear conducted in United States and Australia21.22.
The prevalence of cataract seen in our study was
estimated to be 21.81%.This is almost similar to another study conducted known
as the Beaver eye dam study which estimated an incidence of 21%23.
However the prevalence was higher in other studies such as Zhang Js who
estimated the prevalence of cataract in China to be 35%24. In
another study done in Singapore the prevalence reported was 34.7% (95% CI,
31.5, 38.0)25.
Limitations of the study are that prevalence
of age related cataracts alone is difficult to determine as there are
multifactorial causes of Cataract formation such as increasing age, trauma, use
of steroids etc. Also to study association of tobacco smoking with cataract a
larger sample size is recommended. People were vague in their history regarding
the mode of tobacco consumption and were especially hesitant to discuss the
duration of its usage because of social stigma. Furthermore as most patients
selected for final evaluation were more than 40 years old in which age related
cataracts are more common it adds more confusion to build any definite
association.
CONCLUSION
The prevalence of
cataract seen in our study was estimated to be 21.81%. There was no significant
association found for gender and cataract development. A significant
association was found between tobacco consumption and occurrence of different
cataract types of which the most common type of cataract seen was posterior
subcapsular.
Authors
Affiliation
Dr. Saba Alkhairy
MBBS, FCPS, (OPHTH)
Assistant Professor DIMC, DUHS
Dr. Farnaz Siddiqui
MBBS, FCPS, (OPHTH)
Assistant Professor DIMC, DUHS
Dr. Mazhar UL Hassan
MBBS, MCPS, FCPS, (OPHTH)
Professor and Head of department
DIMC, DUHS
Dr. Arif Nayani
MBBS, Medical officer
DIMC, DUHS
Authors
Contribution
Dr. Saba Alkhairy
Data collection, analysis and
manuscript writing.
Dr. Farnaz Siddiqui
Data collection and analysis.
Dr. Mazhar UL Hassan
Study design and critical analysis.
Dr. Arif Nayani
Data collection and literature
review.
Conflict
of Interest
The authors have no conflict of
interest to declare.
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