- Email: [email protected]
The epidemiology of dry eye in Melbourne, Australia1
The Epidemiology of Dry Eye in Melbourne, Australia Cathy A. McCarty, Yury L. Stanislausky,
PhD, MPH,’ Aashish K. Bansal, MD,2 Patricia M. Livingston, MD,’ Hugh R. Taylor, MD, FRACO’
PhD,’
Objective: To describe the epidemiology of dry eye in the adult population of Melbourne, Australia. Design: A cross-sectional prevalence study. Partlclpants: Participants were recruited by a household census from two of nine clusters of the Melbourne Visual Impairment Project, a population-based study of age-related eye disease in the 40 and older age group of Melbourne, Australia. Nine hundred and twenty-six (82.3% of eligible) people participated: 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. Main Outcome Measures: Self-reported symptoms of dry eye were elicited by an interviewer-administered questionnaire. Four objective assessments of dry eye were made: Schirmer’s test, tear film breakup time, rose bengal staining, and fluorescein cornea1 staining. A standardized clinical slit-lamp examination was performed on all participants. Dry eye for the individual signs or symptoms was defined as: rose bengal > 3, Schirmers < 8, tear film breakup time < 8, > ‘& fluorescein staining, and severe symptoms (3 on a scale of 0 to 3). Results: Dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer’s test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. Women were more likely to report severe symptoms of dry eye (odds ratio [OR] = 1.85; 95% confidence limits [CL] = 1 .Ol, 3.41). Risk factors for two or more signs of dry eye include age (OR = 1.04; 95% CL = 1 .Ol, 1.06), and self-report of arthritis (OR = 3.27; 95% CL = 1.74, 6.17). These results were not changed after excluding the 21 people (2.27%) who wore contact lenses. Conclusions: These are the first reported population-based data of dry eye in Australia. The prevalence of dry eye varies by sign and symptom. Ophthalmology 7998; 705:7 7 74- 7 7 79
Dry eye, or keratoconjunctivitis sicca (KCS), is a distressing problem for both patients and ophthalmologists. The prevalence of this condition in the community is unknown because patients present for assessment and treatment when the condition is moderate to severe and the symptoms have become intolerable. Even at this stage, the diagnosis may not be made if the ophthalmologist does not perform the diagnostic tests required to detect dry eye. The condition of dry eye is therefore often overlooked and hence underdiagnosed in the population. Available prevalence data have originated from clinics or
Originally received: April 23, 1997. Revision accepted: December 1, 1997. ’ University of Melbourne, Department of Ophthalmology, Melbourne, Australia. * LV Prasad Eye Institute, Hyderabad, India. Supported in part by The Victorian Health Promotion Foundation, Melbourne, the Ansell Ophthalmology Foundation, Melbourne, the Dorothy Edols Estate, Melbourne, and the National Health and Medical Research Council, including the Sir John Eccles Award to Professor Hugh Taylor, Canberra, Australia. Consumable items for the dry eye examinations were provided by Smith & Nephew, Melbourne, Australia, and Alcon Australia, Sydney, Australia. Reprints requests to Cathy A. McCarty, PhD, MPH, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisbome Street, East Melbourne, VIC 3002, Australia.
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hospitals and thus comprise a select group of patients who are not representative of the population in general.’ The diagnosis of dry eye is often difficult because of a lack of sufficiently discriminatory clinical diagnostic techniques that provide consistent and unambiguous values.2-5 In the milder form of the disease,diagnosis depends on cumulative evidence gathered from performing a variety of diagnostic methods. Performing a battery of tests to diagnose a single diseaseis not always possible or feasible. It would, therefore, be convenient to know which of the available tests is most accurate and reliable and consistent with subjective symptoms of dry eye. The purpose of this study was to describe the epidemiology of dry eye in the Melbourne population aged 40 years and over.
Materials
and Methods
Study Population Details of the Melbourne Visual Impairment Project (Melbourne VIP) have been described previously.6 This study comprised
residentsat two testsitesof the MelbourneVIP (28% of thetotal study population). Eligible residents were identified through a private household census. To be eligible, a resident had to be 40 years of age or older at the end of the current calender year and a resident at the address for at least 6 months. Eligible residents were invited to attend a local examination center.
McCarty
et al * Epidemiology
Table 1. Definition Symptom
Grade 0 Absence of positive sensation
Foreign body sensatmn
Absent
Itchmg Tearmg
No abnormal sensation Absence
Dryness
Absent
Photophobia
Absent
Mild-awareness of one’s eyes, difficulty in describing specific type of discomfort Mtld-similar to the sensation of fine dust or powder in the eye Mild-aware of intermittent sensation Mild-positive sensation of fullness of the conjunctival sac wthout tears spilling over the lid margin Mild-infrequent or intertmttent discomfort in the eyes Mild-very mm~mal light mtolerance which may requtre some degree of sunglass protectlon to eliminate the symptom
Examination History of dry eye symptoms was elicited with an intervieweradminstered questionnaire. The following symptoms were queried and recorded: discomfort, foreign body sensation, dryness, itching, tearing, and photophobia. Participants were asked to grade their experience of each symptom from 0 to 3 (Table 1). If they experienced any symptoms, they were asked whether the symptom was thought to be associated with hay fever. History of dry mouth was elicited and graded by the participant from 0 to 3 (0 = no history, 1 = mild, 2 = moderate, 3 = severe). History of any previously confirmed diagnosis by a doctor of rheumatoid arthritis or Sjogren syndrome was also recorded. Menopausal status, use of hormone replacement therapy, cigarette smoking, alcohol use, and contact lens wear were queried by a trained interviewer during a personal interview on health-related habits. The standardized clinical examination included visual function, slit-lamp examination of the anterior segment, examination of the cornea after fluorescein staining, tear film breakup time, and examination after rose bengal staining.4 The order of the examinations was visual acuity assessment, visual field assessment, installation of local anesthetic, Schirmer’s test, intraocular pressure, installation of dilation drops, 30-minute personal interview, fluorescein staining, tear film breakup time, rose bengal
Table 2. Prevalence of Self-reported
Symptom Discomfort Foreign body sensation Itching Tearmg Dryness Photophobia
of Ocular Symptoms
Grade 1
Discomfort
of Dry Eye
Grade
2
Grade
3
Moderate-ability to descrtbc the pam modality in specific terms Moderate-slmllar to the sensation of sand or dust m the eye Moderate-intermittent sensation with desire to rub Moderate-infrequent or intermittent spilling of tears over the hd margin
Severe-exquiwe ocular, perlocular, or radiating pain requirmg analgesia Severe-similar to the senstation of a hot ember in the eye
Moderate-more frequent but less than constant symptom5 Moderate-infrequent or mntermlttent discomfort In the globe associated with exposure to room hght or sunlight which is only partially relieved by dark glasses or subdued light
Severe-constant or near constant symptoms of dryness that require lubricating drops 4+ times per day Severe-constant or nearly constant pain LT\ the eye that IS not relieved by sunglasses and 1s only reheved by total occlusion of the eye
Severe-constant sensation with Severe-constant spilling of tears margins
awareness of rubbing or nearly constant over the hd
staining, slit-lamp examination, and lens and fundus photography. The Schirmer’s test was performed, following instillation of oxybuprocaine hydrochloride (0.4%) for participant comfort, by placing a 5- X 35-mm strip of dry filter paper in the lower fornix at the junction of lateral and middle thirds, taking care to avoid touching the cornea. The patient was seated in a chair and asked to blink normally. The strip was removed after 5 minutes, and the length of wetting of the filter paper was determined with a measuring scale. Both eyes were tested simultaneously. The test results were considered positive if the length of wetting obtained was less than 8 mm in 5 minutes. Slit-lamp examination was used to determine the presence of erythema, conjunctival luster, conjunctival discharge, filaments, and dryness of bulbar conjunctiva. Each sign was graded from 0 to 3 (0 = absent, 1 = mild, 2 = moderate, 3 = severe). The fluorescein staining was done by touching the inferior fornix with a dry fluorescein strip while the patient looked up. Presence of any fluorescein staining of the cornea was recorded and graded as 0 (no staining of the cornea1 epithelial surface), 1 (mild staining limited to < ‘!?of the cornea1 epithelial surface), 2 (moderate staining occupying < ‘/* of the cornea1 epithelial surface), or 3 (severe staining of > ‘/* of the cornea1 epithelial surface). Dry eye was defined as moderate or severe fluorescein staining.
Symptoms of Dry Eye in the Worse Eye
No. Assessed
Absent (%)
Mild (%)
Moderate (%)
Severe W)
% of Severe Symptoms Due to Hay Fever
887 895 894 894 895 893
67.9 74.3 60.0 65.5 83.0 49.4
21.0 18.8 28.4 24.9 11.8 34.7
8.9 5.5 9.3 7.6 4.7 10.8
2.3 1.5 2.3 1.9 0.4 4.9
26.7 36.4 90.5 31.3 0 14.7
Ophthalmology Table
Rose bengal Fluorescein
375 (46.5) 720 (89.6)
Continuous Sign
BUT
= breakup
3. Distribution
75 (9.3) 72 (9.0)
Sample Size
Mean
771 838
14.7 11.9
BUT (sets) Schlrmers (mm) trme; NA
= not applicable;
Volume 105, Number of Clinical
Signs
162 (20.1) 12 (1.5)
4.72 1.70
Rose Bengal >3 (scale, O-9)
Age Group (yrs)
Gender
40-49
M F M F M F M F M F M F
50-59 60-69 70-79 80-89 90+
BUT
1116
= breakup
2/80 4/122 7/l 12 19/133 7/l 19 13/91 1 l/58 9/49 5/16 10/22 O/l o/3 tone.
(2.50) (3.28) (6.25) (14.3) (5.88) (14.3) (19.0) (18.4) (31.25) (45.45) (0) (0)
(Percent)
BUT < 8 bed 4/79 8/l 19 7/108 16/131 4/114 5/86 5/53 4/46 5/13 7/19 l/l
o/2
(5.06) (6.72) (6.48) (12.2) (3.51) (5.81) (9.43) (8.7) (38.5) (36.8) (100) (0)
23 (2.9) NA
8 (1.0) NA
1 (0.1) NA
Eye Cutoff
Range
if=2SD(%)
if < I ‘/2 SD (%)
if <
3.33, 30 0, 57
5 (1.2%) 8 (16.3%)
8 (8.6%) 9 (20.9%)
10 (16.9%) 10 (25.4%)
I SD (%)
deviatmn.
Data Management and Analyses Interview data were entered directly into the computer. Other data were doubly entered and verified. The worse eye was used 4. Prevalence
55 (6.8) NA
Dry
The tear film breakup time was recorded after fluorescein staining. The patient was asked to blink several times and then hold the eyes open. The cornea was scanned with a slit lamp using a cobalt-blue filter. A dry area was indicated by appearance of a black spot or line. The time in seconds between the last blink and the appearance of a random dry spot was recorded as the tear film breakup time. The test was repeated three times in each eye, and the average was recorded. The test was considered positive if the average tear film breakup time was less than 8 seconds. Rose bengal staining was performed by instilling a drop of preservative-free 1% rose bengal (4,.5,6,7-tetrachloro-2,4,5,7tetraiodo fluorescein sodium) Minims stain (Smith & Nephew, Melbourne, Australia) in the inferior fornix of each eye and examining the eye under a slit lamp for any staining of the conjunctiva or the cornea. The degree of staining was recorded separately for the temporal conjunctiva, cornea, and nasal conjunctiva on a scale of O-3 in comparison to standard diagrams. The three scores were then added to obtain the total score of 0 to 9 for each eye.4 Only staining of the conjunctiva in the interpalpebral portion was taken into consideration. Any staining in the inferior fornix was ignored. The test was considered positive if the value obtained was more than 3.
Table
Eye in the Population
107 (13.3) 0 (0)
Standard Deviation
SD = standard
of Dry
6, June 1998
of Signs
and Any
Schirmers (mm) 12/81 24/120 20/115 22/142 15/119 12/98 7/62 13/57 2/14 7125 l/l 214
< 8
(14.8) (20.0) (17.4) (15.5) (12.6) (12.2) (11.3) (22.8) (14.3) (28.0) (100) (50.0)
for analysis because in a developed country such as Australia, the presence of bothersome signs and symptoms of dry eye in even one eye would be treated and thus have implications for the healthcare system. Variables that were not normally distributed were transformed prior to analysis to allow for parametric analyses. All analyses were performed with SAS Version 6.1 (SAS Institute, Cary, NC). Chi-square tests were used to evaluate significant differences in proportions among groups. Backwards logistic regression was employed to assess the independent association of potential risk factors with dry eye. A P value < 0.05 was considered to be statistically significant.
Results Nine hundred and twenty-six (82.3% of eligible) people participated; 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. They were not significantly different from the participants of the other seven test sites with respect to age (r-test = 1.56; P = 0.12) or gender (chi-square test 0.17; P = 0.68). The Melbourne VIP study cohort is not significantly different from the Melbourne population with regard to age, gender, education, or living arrangements.7 Dry eye had been previously diagnosed in eight (0.87%) of the cohort and Sjogren’s disease was present in two (0.2%) people. One hundred and five people (12.9%) self-reported a Symptoms
of Dry
Fluorescein Stain > l/3
O/78 (0) l/l22 Z/l11 3/134 l/l 19 2/91 l/58 2/49
(0.82) (1.80) (2.24) (0.84) (2.20) (1.72) (4.08)
O/16 (0) 0122 (0) O/l (0) o/3
(0)
Eye by Age
22 Signs 2181 5/123 7/l 12 171135 3/120 4/92 4/58 5/50 5/16 7122 l/l o/3
(2.47) (4.07) (6.25) (12.6) (2.50) (4.35) (6.90) (10.0) (31.25) (31.8) (100) (0)
and Gender Any Severe symptom (including hay fever related)
Any Severe Symptom (no hay fever)
13/83 16/134 9/124 1 l/148 6/126 1 l/102 6163 IO/57 2/16 7/30 O/l o/4
5/84 8/135 4/124 71149 31127 4/102 3/64 8/59 l/l6 6/30 O/l o/4
(15.7) (11.9) (7.26) (7.43) (4.76) (10.8) (9.52) (17.5) (12.5) (23.3) (0) (0)
(5.95) (5 93) (3.23) (4.70) (2.36) (3.92) (4.69) (13.6) (6.25) (20.0) (0) (0)
McCarty
Agreement of Clinical Signs 7 of Dry Eye /
et al . Epidemiology
Schirmers
\ 91
Rose \ Bengal
I
I
BUT
\
Fluorescein Figure
1. Agreement
of clmcal
signs of dry eye (II = 615).
previous diagnosis of arthritis, and I3 (1.5%) people reported symptoms of extreme dry mouth. Although only 148 (16.1%) of the cohort smoked cigarettes currently, 301 (39.0%) had smoked at some time in their lives. Only 21 people (2.27%) wore contact lenses. The self-reported prevalence of specific symptoms of dry eye in the worst eye is quite low, with only four (0.4%) people reporting severe dryness (Table 2). The most commonly reported severe symptom was photophobia (n = 44; 4.9%). None of the extreme dryness was attributed to hay fever, whereas nearly all of the itchy symptoms were. Normative values for the clinical signs of dry eye in this cohort are presented in Table 3. Data are presented for the worse eye only, but the agreement between left and right eyes was very high for all clinical signs. The Pearson correlation coefficient for tear film breakup time was 0.89. The Spearman correlation coefficient was 0.88 for rose bengal, 0.83 for fluorescein stain, and 0.72 for Schirmer’s test. The distribution of the two categorical signs differs considerably, with far more people displaying no signs of dry eye on Fluorescein stain than on rose bengal stain. The tear film breakup time was normally distributed in the population, and the standard cutoff for dry eye diagnosis is l’/, SD less than the mean. The results of the Schirmer’s test were skewed to the right, hence the higher percentage of people diagnosed with dry by using cut-off points based on the standard deviation of the geometric mean. Given these normative values, the one-tailed cutoff values to define dry eye of 3 for rose bengal, 2 or more for fluorescein, < 8 for tear film breakup time, and < 8 for Schirmers seemed reasonable. Lowering the cutoff value for Schirmer’s test to 5 would decrease the prevalence of dry eye to 5.5% for this test. The age- and gender-specific prevalence of dry eye varied according to the different clinical signs and the presence of any
of Dry Eye
severe symptom (Table 4). Overall, dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer’s test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. The age-specific prevalence of dry eye was not significantly different between the genders, except for the age groups SO-59 and 60-69 by rose bengal assessment. Women were significantly more likely to be diagnosed with dry eye in both of these age groups (P = 0.013 and P = 0.017, respectively). There were also no gender differences in overall dry eye prevalence except by rose bengal. Controlling for age, men were about half as likely as women to be diagnosed with dry eye by rose bengal staining (odds ratio [OR] = 0.54; 95% confidence limits [CL] = 0.34, 0.87). Agreement between the various clinical signs of dry eye fol the 635 people that had all four examinations varied (Fig I ). Only one person had all four signs of dry eye. lntratest agreement appeared to be best for the combination of rose bengal and tear film breakup time, resulting in a prevalence of 27/635 (4.25%). Treatment is rarely based on clinical signs alone, and therefore a comparison of dry eye signs with prevalence of any severe dry eye symptom (including hay fever) was made. The Schirmer’s test was found to be the least discriminating of symptoms (Fig 2). Only 12.4% of people diagnosed with dry eye by Schirmer’s test reported severe symptoms of dry eye compared with 9.27% of people that did not have dry eye by Schirmer’s test (chi-square test = I .2X; P = 0.258). Fluorescein staining was found to be the most discriminating in terms of dry eye symptomatology (chi-square test = 7.94; P = 0.005). Discrimination for all of the tests, except rose bengal, was improved when the symptoms associated with hay fever were removed (data not presented). The following factors were entered into multivariate logistic regression models to predict the presence of two or more clinical signs of dry eye or severe symptoms of dry eye not associated with hay fever: age, gender, use of contact lenses, self-reported diagnosis of arthritis, cigarette smoker, previous eye injury, and definite symptoms of dry mouth. In separate models for women, menopausal status and use of hormone replacement therapy were also entered into the models. Women were nearly twice as likely to report symptoms of dry eye (OR = 1.85; 95% CL = 1.01, 3.41) but were not significantly more likely to have two or more signs of dry eye. There was a significant positive relationship between age and the prevalence of two or more signs of dry eye (OR = 1.04; 95% CL = 1.01, 1.06). After backwards elimination, the only other variable that remained in any of the models was self-report of arthritis. People with two
Rose
Bengal
BUT
Schirmers Clinical
Sign
Fluorescein
2+ signs
Ophthalmology
Volume 105, Number
or more clinical signs of dry eye were more than three times as likely to report a history of arthritis than people without dry eye (OR = 3.27; 95% CL = 1.74, 6.17). None of the results was affected by the exclusion of the 21 people who wore contact lenses.
Discussion There is controversy in the literature regarding the criteria for diagnosis of dry eye based on clinical diagnostic tests. All four tests assessed in this study have limited diagnostic value if performed individually or in the absence of severe symptoms. It is not uncommon to find an abnormality of a single tear function test4 To our knowledge, there has been only one published paper with population-based data regarding the prevalence of dry eye in the literature.8 That study of elderly Americans found that the prevalence of dry eye varied from 4.2% to 46%, depending on the sign or symptoms; no age-, gender-, or race-specific differences in dry eye prevalence were detected.8-9 A study that investigated the hospital epidemiology of dry eye found that 0.46% of all ophthalmic outpatients suffered from dry eye.’ The prevalence of dry eye increased significantly with age in our study. This is consistent with reports that tear secretion decreases with age.‘-” A higher prevalence of dry eye in women by rose bengal testing in the immediate postmenopausal age groups indicates a possible relationship with hormonal change. Tielsch and coworkers have suggested that history of oophorectomy was associated with a modest increased risk of dry eye (presented as a paper at the Association for Research in Vision and Ophthalmology Annual Meeting, Fort Lauderdale, FL, 1996), but we were unable to confirm that finding in our study cohort. Lamberts et al” showed that tear production decreases significantly in women in the sixth decade (50-59 years), which is consistent with our findings. Although dry eye can be caused by a group of diseases, patient symptoms are similar for each cause and include dryness, foreign body sensation, discomfort, itching, tearing, and photophobia.13 Allergic diseases, however, can often cause symptoms similar to dry eye, and this causes confusion in the diagnosis. 14*15All of the above-mentioned symptoms are complaints in patients with hay fever. We found that up to almost half of symptoms were related to hay fever and that the predictive value of dry eye signs was improved if hay fever was considered. Conflicting information commonly results from the Schirmer’s test. It has been reported in the past that Schirmer’s test has a low sensitivity but high specificity.’ In a study in which the diagnosis of dry eye was made on symptoms alone, Schirmer’s test had a reasonably high specificity and sensitivity.’ Farris et al” found a sensitivity of 10% and a specificity of 100%. It has been suggested that the Schirmer’s test with anesthesia is not capable of measuring baseline tear secretion independent of reflex tearsI We found Schirmer’s test to yield the highest number of false-positives in terms of symptomatology. Our results would have been influenced in part by the use of anesthesia. We elected to use a local anesthetic to minimize discomfort in the study volunteers. Tear film breakup time is the only direct evidence of stability of the tear film. Fluorescein itself reduces the breakup time of the tear film.4.” ” The reduction in breakup time, however, is more common in cases of dry eye than in normals. Hence, this test acts as a sort of positive provocative test.” A drawback of
1118
6, June 1998
tear film breakup time is that it has a high variation coefficient, and therefore repeated readings are mandatory. However, when carefully conducted, the results can be quite meaningful. Tear film breakup time is most useful when it is normal, suggesting a stable tear film.” Previous studies have shown the rose bengal test to have high sensitivity and specificity.‘,’ The results of the rose bengal test can be fallacious if a Schirmer’s test is done beforehand, as the contact of filter paper strip with the conjunctiva and the cornea can cause staining.13 When interpreting the results of rose bengal testing, staining in the lower formatting was ignored for this reason and only the staining in the interpalpebral area was considered. The varying prevalence rate of dry eye by sign and symptom as well as the poor agreement between signs and symptoms has been demonstrated recently.’ Ultimately, the choice of dry eye test for population-screening purposes must be based on the desired level of sensitivity and specificity, balanced with consideration of patient comfort. For clinical purposes, patient symptoms and complaint will obviously influence the choice of diagnostic tests to use. This study highlights, for the first time, the magnitude of dry eye in the Australian population. It also shows that of the four clinical tests, Schirmer’s test is the least useful as a single tool for the diagnosis of dry eye. The major strength of this study results from the population-based design that resulted in a sample that is representative of the entire Melbourne population aged 40 and over. Acknowledgements. The authors acknowledge the contributions of the following individuals: Ms. Marie Bissinella, Dr. Charles Guest, Ms. Sharon Lee, and Mr. Matthew Wensor.
References 1. Khurana AK, Choudhary R, Ahluwalia BK, Gupta S. Hospital epidemiology of dry eye. Indian J Ophthalmol 1991;39:55-8. 2. Lucca JA, Nunez JN, Farris RL. A comparison of diagnostic tests for keratoconjunctivitis sicca: lactolate, Schirmer, and tear osmolarity. CLAO J 1990; 16:109-12. 3. Farris RL, Gilbard JP, Stuchell RN, Mandel ID. Diagnostic tests in keratoconjunctivitis sicca. CLAO J 1983;9:23-8. 4. Taylor HR, Louis WJ. Significance of tear function test abnormalities. Ann Ophthalmol 1980; 1253 l-5. 5. Goren MB, Goren SB. Diagnostic tests in patients with symptoms of keratoconjunctivitis sicca. Am J Ophthalmol 1988; 106:570-4. 6. Livingston PM, Carson CA, Stanislavsky YL, et al. Methods for a population-based study of eye disease: the Melbourne Visual Impairment Project. Ophthalmic Epidemiol 1994; 1:139-48. 7. Livingston PM, Lee SE, McCarty CA, Taylor HR. A comparison of participants with non-participants in a population-based epidemiologic study: the Melbourne Visual Impairment Project. Ophthalmic Epidemiol 1997; 4:73-81. 8. Schein OD, Tielsch JM, Mufioz B, et al. Relation between signs and symptoms of dry eye in the elderly. A population-based perspective. Ophthalmology 1997; 104:1395-1401. 9. Henderson JW, Prough WA. Influence of age and sex on flow of tears. Arch Ophthalmol 1950;43:224-31.
McCarty
et al * Epidemiology
10. de Roetth A Sr. Lacrimation in normal eyes. Arch Ophthalmol 1953;49:185-9. 11. Mathers WD, Lane JA, Zimmerman MB. Tear film changes associated with normal aging. Cornea 1996; 15:229-34. 12. Lamberts DW, Foster CS, Perry HD. Schirmer test after topical anesthesia and the tear meniscus height in normal eyes. Arch Ophthalmol 1979;97:1082-5. 13. Bron AJ. Duke-Elder Lecture. Prospects for the dry eye. Trans Ophthalmol Sot UK 1985; 104:801-26. 14. Toda I, Shimazaki J, Tsubota K. Dry eye with only de-
Historical
of Dry Eye
creased tear break-up time is sometimes associated with allergic conjunctivitis. Ophthalmology 1995; 102:302-9. 15. Fujishima H, Toda I, Shimazaki J, Tsubota K. Allergic conjunctivitis and dry eye. Br J Ophthalmol 1996; 80:9947. 16. Clinch TE, Benedetto DA, Felberg NT, Laibson PR. Schirmer’s test. A closer look. Arch Ophthalmol 1983; 101:1383-6. 17. Taylor HR. Studies on the tear film in climatic droplet keratopathy and pterygium. Arch Ophthalmol 1980;98:86-8.
Image
Pages from Soemmerring, Samuel Thomas, Abblidungen des Menschlichen Samuel Thomas Soemmerring had an illustrious career as an anatomist, Like so many great physicians of his day, Soemmerring himself produced here) based on his own observations. This particular work, published in
Auges, Frankfurt, 1801. professor, and surgeon. the illustrations (shown 1801, made use of his
depictions of the human sense organs and are considered his finest anatomic illustrations. are two plates from the book and an additional portrait taken from an unknown source.*
Included
* Courtesy of the Museum of Ophthalmology, Foundation of the American Academy of Ophthalmology,San t+rancisco, California.
PhD, MPH,’ Aashish K. Bansal, MD,2 Patricia M. Livingston, MD,’ Hugh R. Taylor, MD, FRACO’
PhD,’
Objective: To describe the epidemiology of dry eye in the adult population of Melbourne, Australia. Design: A cross-sectional prevalence study. Partlclpants: Participants were recruited by a household census from two of nine clusters of the Melbourne Visual Impairment Project, a population-based study of age-related eye disease in the 40 and older age group of Melbourne, Australia. Nine hundred and twenty-six (82.3% of eligible) people participated: 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. Main Outcome Measures: Self-reported symptoms of dry eye were elicited by an interviewer-administered questionnaire. Four objective assessments of dry eye were made: Schirmer’s test, tear film breakup time, rose bengal staining, and fluorescein cornea1 staining. A standardized clinical slit-lamp examination was performed on all participants. Dry eye for the individual signs or symptoms was defined as: rose bengal > 3, Schirmers < 8, tear film breakup time < 8, > ‘& fluorescein staining, and severe symptoms (3 on a scale of 0 to 3). Results: Dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer’s test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. Women were more likely to report severe symptoms of dry eye (odds ratio [OR] = 1.85; 95% confidence limits [CL] = 1 .Ol, 3.41). Risk factors for two or more signs of dry eye include age (OR = 1.04; 95% CL = 1 .Ol, 1.06), and self-report of arthritis (OR = 3.27; 95% CL = 1.74, 6.17). These results were not changed after excluding the 21 people (2.27%) who wore contact lenses. Conclusions: These are the first reported population-based data of dry eye in Australia. The prevalence of dry eye varies by sign and symptom. Ophthalmology 7998; 705:7 7 74- 7 7 79
Dry eye, or keratoconjunctivitis sicca (KCS), is a distressing problem for both patients and ophthalmologists. The prevalence of this condition in the community is unknown because patients present for assessment and treatment when the condition is moderate to severe and the symptoms have become intolerable. Even at this stage, the diagnosis may not be made if the ophthalmologist does not perform the diagnostic tests required to detect dry eye. The condition of dry eye is therefore often overlooked and hence underdiagnosed in the population. Available prevalence data have originated from clinics or
Originally received: April 23, 1997. Revision accepted: December 1, 1997. ’ University of Melbourne, Department of Ophthalmology, Melbourne, Australia. * LV Prasad Eye Institute, Hyderabad, India. Supported in part by The Victorian Health Promotion Foundation, Melbourne, the Ansell Ophthalmology Foundation, Melbourne, the Dorothy Edols Estate, Melbourne, and the National Health and Medical Research Council, including the Sir John Eccles Award to Professor Hugh Taylor, Canberra, Australia. Consumable items for the dry eye examinations were provided by Smith & Nephew, Melbourne, Australia, and Alcon Australia, Sydney, Australia. Reprints requests to Cathy A. McCarty, PhD, MPH, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisbome Street, East Melbourne, VIC 3002, Australia.
1114
hospitals and thus comprise a select group of patients who are not representative of the population in general.’ The diagnosis of dry eye is often difficult because of a lack of sufficiently discriminatory clinical diagnostic techniques that provide consistent and unambiguous values.2-5 In the milder form of the disease,diagnosis depends on cumulative evidence gathered from performing a variety of diagnostic methods. Performing a battery of tests to diagnose a single diseaseis not always possible or feasible. It would, therefore, be convenient to know which of the available tests is most accurate and reliable and consistent with subjective symptoms of dry eye. The purpose of this study was to describe the epidemiology of dry eye in the Melbourne population aged 40 years and over.
Materials
and Methods
Study Population Details of the Melbourne Visual Impairment Project (Melbourne VIP) have been described previously.6 This study comprised
residentsat two testsitesof the MelbourneVIP (28% of thetotal study population). Eligible residents were identified through a private household census. To be eligible, a resident had to be 40 years of age or older at the end of the current calender year and a resident at the address for at least 6 months. Eligible residents were invited to attend a local examination center.
McCarty
et al * Epidemiology
Table 1. Definition Symptom
Grade 0 Absence of positive sensation
Foreign body sensatmn
Absent
Itchmg Tearmg
No abnormal sensation Absence
Dryness
Absent
Photophobia
Absent
Mild-awareness of one’s eyes, difficulty in describing specific type of discomfort Mtld-similar to the sensation of fine dust or powder in the eye Mild-aware of intermittent sensation Mild-positive sensation of fullness of the conjunctival sac wthout tears spilling over the lid margin Mild-infrequent or intertmttent discomfort in the eyes Mild-very mm~mal light mtolerance which may requtre some degree of sunglass protectlon to eliminate the symptom
Examination History of dry eye symptoms was elicited with an intervieweradminstered questionnaire. The following symptoms were queried and recorded: discomfort, foreign body sensation, dryness, itching, tearing, and photophobia. Participants were asked to grade their experience of each symptom from 0 to 3 (Table 1). If they experienced any symptoms, they were asked whether the symptom was thought to be associated with hay fever. History of dry mouth was elicited and graded by the participant from 0 to 3 (0 = no history, 1 = mild, 2 = moderate, 3 = severe). History of any previously confirmed diagnosis by a doctor of rheumatoid arthritis or Sjogren syndrome was also recorded. Menopausal status, use of hormone replacement therapy, cigarette smoking, alcohol use, and contact lens wear were queried by a trained interviewer during a personal interview on health-related habits. The standardized clinical examination included visual function, slit-lamp examination of the anterior segment, examination of the cornea after fluorescein staining, tear film breakup time, and examination after rose bengal staining.4 The order of the examinations was visual acuity assessment, visual field assessment, installation of local anesthetic, Schirmer’s test, intraocular pressure, installation of dilation drops, 30-minute personal interview, fluorescein staining, tear film breakup time, rose bengal
Table 2. Prevalence of Self-reported
Symptom Discomfort Foreign body sensation Itching Tearmg Dryness Photophobia
of Ocular Symptoms
Grade 1
Discomfort
of Dry Eye
Grade
2
Grade
3
Moderate-ability to descrtbc the pam modality in specific terms Moderate-slmllar to the sensation of sand or dust m the eye Moderate-intermittent sensation with desire to rub Moderate-infrequent or intermittent spilling of tears over the hd margin
Severe-exquiwe ocular, perlocular, or radiating pain requirmg analgesia Severe-similar to the senstation of a hot ember in the eye
Moderate-more frequent but less than constant symptom5 Moderate-infrequent or mntermlttent discomfort In the globe associated with exposure to room hght or sunlight which is only partially relieved by dark glasses or subdued light
Severe-constant or near constant symptoms of dryness that require lubricating drops 4+ times per day Severe-constant or nearly constant pain LT\ the eye that IS not relieved by sunglasses and 1s only reheved by total occlusion of the eye
Severe-constant sensation with Severe-constant spilling of tears margins
awareness of rubbing or nearly constant over the hd
staining, slit-lamp examination, and lens and fundus photography. The Schirmer’s test was performed, following instillation of oxybuprocaine hydrochloride (0.4%) for participant comfort, by placing a 5- X 35-mm strip of dry filter paper in the lower fornix at the junction of lateral and middle thirds, taking care to avoid touching the cornea. The patient was seated in a chair and asked to blink normally. The strip was removed after 5 minutes, and the length of wetting of the filter paper was determined with a measuring scale. Both eyes were tested simultaneously. The test results were considered positive if the length of wetting obtained was less than 8 mm in 5 minutes. Slit-lamp examination was used to determine the presence of erythema, conjunctival luster, conjunctival discharge, filaments, and dryness of bulbar conjunctiva. Each sign was graded from 0 to 3 (0 = absent, 1 = mild, 2 = moderate, 3 = severe). The fluorescein staining was done by touching the inferior fornix with a dry fluorescein strip while the patient looked up. Presence of any fluorescein staining of the cornea was recorded and graded as 0 (no staining of the cornea1 epithelial surface), 1 (mild staining limited to < ‘!?of the cornea1 epithelial surface), 2 (moderate staining occupying < ‘/* of the cornea1 epithelial surface), or 3 (severe staining of > ‘/* of the cornea1 epithelial surface). Dry eye was defined as moderate or severe fluorescein staining.
Symptoms of Dry Eye in the Worse Eye
No. Assessed
Absent (%)
Mild (%)
Moderate (%)
Severe W)
% of Severe Symptoms Due to Hay Fever
887 895 894 894 895 893
67.9 74.3 60.0 65.5 83.0 49.4
21.0 18.8 28.4 24.9 11.8 34.7
8.9 5.5 9.3 7.6 4.7 10.8
2.3 1.5 2.3 1.9 0.4 4.9
26.7 36.4 90.5 31.3 0 14.7
Ophthalmology Table
Rose bengal Fluorescein
375 (46.5) 720 (89.6)
Continuous Sign
BUT
= breakup
3. Distribution
75 (9.3) 72 (9.0)
Sample Size
Mean
771 838
14.7 11.9
BUT (sets) Schlrmers (mm) trme; NA
= not applicable;
Volume 105, Number of Clinical
Signs
162 (20.1) 12 (1.5)
4.72 1.70
Rose Bengal >3 (scale, O-9)
Age Group (yrs)
Gender
40-49
M F M F M F M F M F M F
50-59 60-69 70-79 80-89 90+
BUT
1116
= breakup
2/80 4/122 7/l 12 19/133 7/l 19 13/91 1 l/58 9/49 5/16 10/22 O/l o/3 tone.
(2.50) (3.28) (6.25) (14.3) (5.88) (14.3) (19.0) (18.4) (31.25) (45.45) (0) (0)
(Percent)
BUT < 8 bed 4/79 8/l 19 7/108 16/131 4/114 5/86 5/53 4/46 5/13 7/19 l/l
o/2
(5.06) (6.72) (6.48) (12.2) (3.51) (5.81) (9.43) (8.7) (38.5) (36.8) (100) (0)
23 (2.9) NA
8 (1.0) NA
1 (0.1) NA
Eye Cutoff
Range
if=2SD(%)
if < I ‘/2 SD (%)
if <
3.33, 30 0, 57
5 (1.2%) 8 (16.3%)
8 (8.6%) 9 (20.9%)
10 (16.9%) 10 (25.4%)
I SD (%)
deviatmn.
Data Management and Analyses Interview data were entered directly into the computer. Other data were doubly entered and verified. The worse eye was used 4. Prevalence
55 (6.8) NA
Dry
The tear film breakup time was recorded after fluorescein staining. The patient was asked to blink several times and then hold the eyes open. The cornea was scanned with a slit lamp using a cobalt-blue filter. A dry area was indicated by appearance of a black spot or line. The time in seconds between the last blink and the appearance of a random dry spot was recorded as the tear film breakup time. The test was repeated three times in each eye, and the average was recorded. The test was considered positive if the average tear film breakup time was less than 8 seconds. Rose bengal staining was performed by instilling a drop of preservative-free 1% rose bengal (4,.5,6,7-tetrachloro-2,4,5,7tetraiodo fluorescein sodium) Minims stain (Smith & Nephew, Melbourne, Australia) in the inferior fornix of each eye and examining the eye under a slit lamp for any staining of the conjunctiva or the cornea. The degree of staining was recorded separately for the temporal conjunctiva, cornea, and nasal conjunctiva on a scale of O-3 in comparison to standard diagrams. The three scores were then added to obtain the total score of 0 to 9 for each eye.4 Only staining of the conjunctiva in the interpalpebral portion was taken into consideration. Any staining in the inferior fornix was ignored. The test was considered positive if the value obtained was more than 3.
Table
Eye in the Population
107 (13.3) 0 (0)
Standard Deviation
SD = standard
of Dry
6, June 1998
of Signs
and Any
Schirmers (mm) 12/81 24/120 20/115 22/142 15/119 12/98 7/62 13/57 2/14 7125 l/l 214
< 8
(14.8) (20.0) (17.4) (15.5) (12.6) (12.2) (11.3) (22.8) (14.3) (28.0) (100) (50.0)
for analysis because in a developed country such as Australia, the presence of bothersome signs and symptoms of dry eye in even one eye would be treated and thus have implications for the healthcare system. Variables that were not normally distributed were transformed prior to analysis to allow for parametric analyses. All analyses were performed with SAS Version 6.1 (SAS Institute, Cary, NC). Chi-square tests were used to evaluate significant differences in proportions among groups. Backwards logistic regression was employed to assess the independent association of potential risk factors with dry eye. A P value < 0.05 was considered to be statistically significant.
Results Nine hundred and twenty-six (82.3% of eligible) people participated; 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. They were not significantly different from the participants of the other seven test sites with respect to age (r-test = 1.56; P = 0.12) or gender (chi-square test 0.17; P = 0.68). The Melbourne VIP study cohort is not significantly different from the Melbourne population with regard to age, gender, education, or living arrangements.7 Dry eye had been previously diagnosed in eight (0.87%) of the cohort and Sjogren’s disease was present in two (0.2%) people. One hundred and five people (12.9%) self-reported a Symptoms
of Dry
Fluorescein Stain > l/3
O/78 (0) l/l22 Z/l11 3/134 l/l 19 2/91 l/58 2/49
(0.82) (1.80) (2.24) (0.84) (2.20) (1.72) (4.08)
O/16 (0) 0122 (0) O/l (0) o/3
(0)
Eye by Age
22 Signs 2181 5/123 7/l 12 171135 3/120 4/92 4/58 5/50 5/16 7122 l/l o/3
(2.47) (4.07) (6.25) (12.6) (2.50) (4.35) (6.90) (10.0) (31.25) (31.8) (100) (0)
and Gender Any Severe symptom (including hay fever related)
Any Severe Symptom (no hay fever)
13/83 16/134 9/124 1 l/148 6/126 1 l/102 6163 IO/57 2/16 7/30 O/l o/4
5/84 8/135 4/124 71149 31127 4/102 3/64 8/59 l/l6 6/30 O/l o/4
(15.7) (11.9) (7.26) (7.43) (4.76) (10.8) (9.52) (17.5) (12.5) (23.3) (0) (0)
(5.95) (5 93) (3.23) (4.70) (2.36) (3.92) (4.69) (13.6) (6.25) (20.0) (0) (0)
McCarty
Agreement of Clinical Signs 7 of Dry Eye /
et al . Epidemiology
Schirmers
\ 91
Rose \ Bengal
I
I
BUT
\
Fluorescein Figure
1. Agreement
of clmcal
signs of dry eye (II = 615).
previous diagnosis of arthritis, and I3 (1.5%) people reported symptoms of extreme dry mouth. Although only 148 (16.1%) of the cohort smoked cigarettes currently, 301 (39.0%) had smoked at some time in their lives. Only 21 people (2.27%) wore contact lenses. The self-reported prevalence of specific symptoms of dry eye in the worst eye is quite low, with only four (0.4%) people reporting severe dryness (Table 2). The most commonly reported severe symptom was photophobia (n = 44; 4.9%). None of the extreme dryness was attributed to hay fever, whereas nearly all of the itchy symptoms were. Normative values for the clinical signs of dry eye in this cohort are presented in Table 3. Data are presented for the worse eye only, but the agreement between left and right eyes was very high for all clinical signs. The Pearson correlation coefficient for tear film breakup time was 0.89. The Spearman correlation coefficient was 0.88 for rose bengal, 0.83 for fluorescein stain, and 0.72 for Schirmer’s test. The distribution of the two categorical signs differs considerably, with far more people displaying no signs of dry eye on Fluorescein stain than on rose bengal stain. The tear film breakup time was normally distributed in the population, and the standard cutoff for dry eye diagnosis is l’/, SD less than the mean. The results of the Schirmer’s test were skewed to the right, hence the higher percentage of people diagnosed with dry by using cut-off points based on the standard deviation of the geometric mean. Given these normative values, the one-tailed cutoff values to define dry eye of 3 for rose bengal, 2 or more for fluorescein, < 8 for tear film breakup time, and < 8 for Schirmers seemed reasonable. Lowering the cutoff value for Schirmer’s test to 5 would decrease the prevalence of dry eye to 5.5% for this test. The age- and gender-specific prevalence of dry eye varied according to the different clinical signs and the presence of any
of Dry Eye
severe symptom (Table 4). Overall, dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer’s test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. The age-specific prevalence of dry eye was not significantly different between the genders, except for the age groups SO-59 and 60-69 by rose bengal assessment. Women were significantly more likely to be diagnosed with dry eye in both of these age groups (P = 0.013 and P = 0.017, respectively). There were also no gender differences in overall dry eye prevalence except by rose bengal. Controlling for age, men were about half as likely as women to be diagnosed with dry eye by rose bengal staining (odds ratio [OR] = 0.54; 95% confidence limits [CL] = 0.34, 0.87). Agreement between the various clinical signs of dry eye fol the 635 people that had all four examinations varied (Fig I ). Only one person had all four signs of dry eye. lntratest agreement appeared to be best for the combination of rose bengal and tear film breakup time, resulting in a prevalence of 27/635 (4.25%). Treatment is rarely based on clinical signs alone, and therefore a comparison of dry eye signs with prevalence of any severe dry eye symptom (including hay fever) was made. The Schirmer’s test was found to be the least discriminating of symptoms (Fig 2). Only 12.4% of people diagnosed with dry eye by Schirmer’s test reported severe symptoms of dry eye compared with 9.27% of people that did not have dry eye by Schirmer’s test (chi-square test = I .2X; P = 0.258). Fluorescein staining was found to be the most discriminating in terms of dry eye symptomatology (chi-square test = 7.94; P = 0.005). Discrimination for all of the tests, except rose bengal, was improved when the symptoms associated with hay fever were removed (data not presented). The following factors were entered into multivariate logistic regression models to predict the presence of two or more clinical signs of dry eye or severe symptoms of dry eye not associated with hay fever: age, gender, use of contact lenses, self-reported diagnosis of arthritis, cigarette smoker, previous eye injury, and definite symptoms of dry mouth. In separate models for women, menopausal status and use of hormone replacement therapy were also entered into the models. Women were nearly twice as likely to report symptoms of dry eye (OR = 1.85; 95% CL = 1.01, 3.41) but were not significantly more likely to have two or more signs of dry eye. There was a significant positive relationship between age and the prevalence of two or more signs of dry eye (OR = 1.04; 95% CL = 1.01, 1.06). After backwards elimination, the only other variable that remained in any of the models was self-report of arthritis. People with two
Rose
Bengal
BUT
Schirmers Clinical
Sign
Fluorescein
2+ signs
Ophthalmology
Volume 105, Number
or more clinical signs of dry eye were more than three times as likely to report a history of arthritis than people without dry eye (OR = 3.27; 95% CL = 1.74, 6.17). None of the results was affected by the exclusion of the 21 people who wore contact lenses.
Discussion There is controversy in the literature regarding the criteria for diagnosis of dry eye based on clinical diagnostic tests. All four tests assessed in this study have limited diagnostic value if performed individually or in the absence of severe symptoms. It is not uncommon to find an abnormality of a single tear function test4 To our knowledge, there has been only one published paper with population-based data regarding the prevalence of dry eye in the literature.8 That study of elderly Americans found that the prevalence of dry eye varied from 4.2% to 46%, depending on the sign or symptoms; no age-, gender-, or race-specific differences in dry eye prevalence were detected.8-9 A study that investigated the hospital epidemiology of dry eye found that 0.46% of all ophthalmic outpatients suffered from dry eye.’ The prevalence of dry eye increased significantly with age in our study. This is consistent with reports that tear secretion decreases with age.‘-” A higher prevalence of dry eye in women by rose bengal testing in the immediate postmenopausal age groups indicates a possible relationship with hormonal change. Tielsch and coworkers have suggested that history of oophorectomy was associated with a modest increased risk of dry eye (presented as a paper at the Association for Research in Vision and Ophthalmology Annual Meeting, Fort Lauderdale, FL, 1996), but we were unable to confirm that finding in our study cohort. Lamberts et al” showed that tear production decreases significantly in women in the sixth decade (50-59 years), which is consistent with our findings. Although dry eye can be caused by a group of diseases, patient symptoms are similar for each cause and include dryness, foreign body sensation, discomfort, itching, tearing, and photophobia.13 Allergic diseases, however, can often cause symptoms similar to dry eye, and this causes confusion in the diagnosis. 14*15All of the above-mentioned symptoms are complaints in patients with hay fever. We found that up to almost half of symptoms were related to hay fever and that the predictive value of dry eye signs was improved if hay fever was considered. Conflicting information commonly results from the Schirmer’s test. It has been reported in the past that Schirmer’s test has a low sensitivity but high specificity.’ In a study in which the diagnosis of dry eye was made on symptoms alone, Schirmer’s test had a reasonably high specificity and sensitivity.’ Farris et al” found a sensitivity of 10% and a specificity of 100%. It has been suggested that the Schirmer’s test with anesthesia is not capable of measuring baseline tear secretion independent of reflex tearsI We found Schirmer’s test to yield the highest number of false-positives in terms of symptomatology. Our results would have been influenced in part by the use of anesthesia. We elected to use a local anesthetic to minimize discomfort in the study volunteers. Tear film breakup time is the only direct evidence of stability of the tear film. Fluorescein itself reduces the breakup time of the tear film.4.” ” The reduction in breakup time, however, is more common in cases of dry eye than in normals. Hence, this test acts as a sort of positive provocative test.” A drawback of
1118
6, June 1998
tear film breakup time is that it has a high variation coefficient, and therefore repeated readings are mandatory. However, when carefully conducted, the results can be quite meaningful. Tear film breakup time is most useful when it is normal, suggesting a stable tear film.” Previous studies have shown the rose bengal test to have high sensitivity and specificity.‘,’ The results of the rose bengal test can be fallacious if a Schirmer’s test is done beforehand, as the contact of filter paper strip with the conjunctiva and the cornea can cause staining.13 When interpreting the results of rose bengal testing, staining in the lower formatting was ignored for this reason and only the staining in the interpalpebral area was considered. The varying prevalence rate of dry eye by sign and symptom as well as the poor agreement between signs and symptoms has been demonstrated recently.’ Ultimately, the choice of dry eye test for population-screening purposes must be based on the desired level of sensitivity and specificity, balanced with consideration of patient comfort. For clinical purposes, patient symptoms and complaint will obviously influence the choice of diagnostic tests to use. This study highlights, for the first time, the magnitude of dry eye in the Australian population. It also shows that of the four clinical tests, Schirmer’s test is the least useful as a single tool for the diagnosis of dry eye. The major strength of this study results from the population-based design that resulted in a sample that is representative of the entire Melbourne population aged 40 and over. Acknowledgements. The authors acknowledge the contributions of the following individuals: Ms. Marie Bissinella, Dr. Charles Guest, Ms. Sharon Lee, and Mr. Matthew Wensor.
References 1. Khurana AK, Choudhary R, Ahluwalia BK, Gupta S. Hospital epidemiology of dry eye. Indian J Ophthalmol 1991;39:55-8. 2. Lucca JA, Nunez JN, Farris RL. A comparison of diagnostic tests for keratoconjunctivitis sicca: lactolate, Schirmer, and tear osmolarity. CLAO J 1990; 16:109-12. 3. Farris RL, Gilbard JP, Stuchell RN, Mandel ID. Diagnostic tests in keratoconjunctivitis sicca. CLAO J 1983;9:23-8. 4. Taylor HR, Louis WJ. Significance of tear function test abnormalities. Ann Ophthalmol 1980; 1253 l-5. 5. Goren MB, Goren SB. Diagnostic tests in patients with symptoms of keratoconjunctivitis sicca. Am J Ophthalmol 1988; 106:570-4. 6. Livingston PM, Carson CA, Stanislavsky YL, et al. Methods for a population-based study of eye disease: the Melbourne Visual Impairment Project. Ophthalmic Epidemiol 1994; 1:139-48. 7. Livingston PM, Lee SE, McCarty CA, Taylor HR. A comparison of participants with non-participants in a population-based epidemiologic study: the Melbourne Visual Impairment Project. Ophthalmic Epidemiol 1997; 4:73-81. 8. Schein OD, Tielsch JM, Mufioz B, et al. Relation between signs and symptoms of dry eye in the elderly. A population-based perspective. Ophthalmology 1997; 104:1395-1401. 9. Henderson JW, Prough WA. Influence of age and sex on flow of tears. Arch Ophthalmol 1950;43:224-31.
McCarty
et al * Epidemiology
10. de Roetth A Sr. Lacrimation in normal eyes. Arch Ophthalmol 1953;49:185-9. 11. Mathers WD, Lane JA, Zimmerman MB. Tear film changes associated with normal aging. Cornea 1996; 15:229-34. 12. Lamberts DW, Foster CS, Perry HD. Schirmer test after topical anesthesia and the tear meniscus height in normal eyes. Arch Ophthalmol 1979;97:1082-5. 13. Bron AJ. Duke-Elder Lecture. Prospects for the dry eye. Trans Ophthalmol Sot UK 1985; 104:801-26. 14. Toda I, Shimazaki J, Tsubota K. Dry eye with only de-
Historical
of Dry Eye
creased tear break-up time is sometimes associated with allergic conjunctivitis. Ophthalmology 1995; 102:302-9. 15. Fujishima H, Toda I, Shimazaki J, Tsubota K. Allergic conjunctivitis and dry eye. Br J Ophthalmol 1996; 80:9947. 16. Clinch TE, Benedetto DA, Felberg NT, Laibson PR. Schirmer’s test. A closer look. Arch Ophthalmol 1983; 101:1383-6. 17. Taylor HR. Studies on the tear film in climatic droplet keratopathy and pterygium. Arch Ophthalmol 1980;98:86-8.
Image
Pages from Soemmerring, Samuel Thomas, Abblidungen des Menschlichen Samuel Thomas Soemmerring had an illustrious career as an anatomist, Like so many great physicians of his day, Soemmerring himself produced here) based on his own observations. This particular work, published in
Auges, Frankfurt, 1801. professor, and surgeon. the illustrations (shown 1801, made use of his
depictions of the human sense organs and are considered his finest anatomic illustrations. are two plates from the book and an additional portrait taken from an unknown source.*
Included
* Courtesy of the Museum of Ophthalmology, Foundation of the American Academy of Ophthalmology,San t+rancisco, California.