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| ARTICLE |
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| Year : 1967 | Volume
: 15
| Issue : 6 | Page : 222-229 |
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Screening of 1,000 cases for the incidence of simple glaucoma over the age of 35 years
RP Sarda, Hari Charan, RC Khetarpal
Department of Ophthalmology, Sawai Mansingh Medical College and Hospital, Jaipur, India
| Date of Web Publication | 22-Jan-2008 |
Correspondence Address:
R P Sarda
Department of Ophthalmology, Sawai Mansingh Medical College and Hospital, Jaipur
India
 Source of Support: None, Conflict of Interest: None  | Check |
How to cite this article:
Sarda R P, Charan H, Khetarpal R C. Screening of 1,000 cases for the incidence of simple glaucoma over the age of 35 years. Indian J Ophthalmol 1967;15:222-9 |
The purpose of mass screening for the incidence of glaucoma is two fold, first to detect more cases of the elusive chronic simple variety of glaucoma and second to make the public aware of this insidious disease for which a periodic examination by ophthalmologists becomes necessary.
When screening for chronic simple glaucoma is done, it is with an idea to net early cases of glaucoma when one goes fishing for them. One can do his "fishing" in unknown waters where the chances of netting a fish are slim whereas if he does his "fishing" in known waters where fishes may abound, the chances of bringing home the catch are better. This screening was therefore done in hospital patients, particularly in those who came to the eye department, in order to determine the best method of screening in an urban population.
| Materials and Methods | |  |
The screening was done under two groups:
A. Patients with ocular complaints. For this group we screened all patients who came to the eye department of our hospital, excluding those cases with acute symptoms like acute iridocyclitis, corneal ulcers and acute glaucoma and also cases of bilateral cataracts.
B. Patients without ocular complaints. For this we chose at random from those cases admitted in wards other than the eye wards of the hospital.
A study of the incidence of chronic simple glaucoma was therefore undertaken in subjects 35 years old and above. For this work 1,000 persons from both sexes have been screened, 600 to cover group A and 400 to cover group B.
Method of Screening
First a preliminary recording of the age, sex, vision and tension was done in every case.
The intraocular pressure was recorded by weighted Schiotz tonometer with 5.5 gm weight. The tonometric readings were recorded in scale divisions and were converted in mm of mercury according to the 1955 standard.
Persons with intraocular pressure of 22.4 mm of mercury and above were called for re-examination, when a detailed history and special examination of the fundi and the fields, peripheral and central, were recorded.
Persons with intraocular pressure between 22.4 mm and 28.9 mm of mercury were subjected to the water drinking test. A rise of tension of more than 8 mm of mercury was regarded pathological.
The diagnosis of glaucoma was based on the following criteria:
1) Patients having tension 26.6 mm of mercury and above on three different occasions.
2) Patients having tension between 22.4 and 24.4 mm of mercury combined with positive result of one or more of the following examinations:
a) Ophthalmoscopy
b) Fields and
c) Provocative tests
3) Patients whose intraocular pressure repeatedly showed values between 23.4 mm and 24.4 mm of mercury and the results of these tests (ophthalmoscopy, fields and provocative tests) were on the border line, were listed as glaucoma suspects.
Out of 1,000 persons examined, 54 (45 of group A and 9 of group B) had an intraocular tension of 22.4 mm or more and were recalled for detailed investigations. Only 36 turned up, 30 from group A and 6 from group B.
In group A of 30 persons, there were 20 who complained of defective vision, 3 of complete loss of vision, 7 of slight headache and 4 of epiphora in one or both eyes. In group B of 6 persons, defective vision was complained of in 2 and 1 had slight headache.
| Observations | | |
The results of examination of these 36 persons have been tabulated for convenience.
[Table - 1] shows distribution of the subjects according to their age and sex which shows the highest incidece in the age group 40-49 years.
[Table - 2] shows the incidence according to age in the two groups.
The break-up in this table agewise shows clearly that there is a progressive increase of incidence of glaucoma with increasing age and that the age of 35 to 40 would be a convenient lower limit of age to base a survey of this nature.
[Table - 3] summarises and compares in a tabulated form the results of clinical examination in the two groups 58 eyes under group A and 12 eyes under B. Note: 2 persons under group A were one-eyed and so 58 eyes of 30 persons were available for examination.
Peripheral fields could be done in 33 eyes in group A and 12 eyes in group B. Out of 33 fields in group A, 20 were found to be contributory to the diagnosis of glaucoma while in group B of 12, only 4 were contributory.
Central fields could be recorded in 29 eyes in group A as the visual acuity was low in some of the eyes and a few patients did not co-operate while in group B these could be recorded in 10 eyes. Out of the 29 fields recorded in group A, 20 were found to be contributory to the diagnosis whereas in group B of 10, only 4 were so contributory.
[Table - 4] shows the results of the water drinking test which was done in 21 persons whose tension was upto 28.9 mm of mercury.
On the basis of the above investigations, glaucoma was diagnosed in 47 eyes of 27 persons (4.5%) out of 600 cases in group A and 8 eyes of 5 persons (1.25%) out of 400 cases in group B.
Thus out of 36 patients reinvestigated 32 were finally diagnosed as having glaucoma.
Out of 600 males screened, 20 were found to be glaucomatous, while out of 400 females only 12 were found to suffer from glaucoma. The ratio was 3.3:3 i.e. glaucoma was present slightly more in males than females.
| Discussion | | |
With increasing span of life the problem of simple glaucoma is increasing as it usually occurs in the 4th decade of life and after. Early diagnosis is very important in cases of chronic simple glaucoma as it can lead to early treatment. According to KRONFELD and McGARRY (1948), glaucoma when diagnosed and treated early, 81% of patients do not show visual deterioration upto 5 years. On the other hand, 50% of the cases show progressive loss of vision despite treatment when it is diagnosed and treated late.
POLLACK (1966) has drawn attention to three forms of studies concerning screening for glaucoma.
A. Mass screening of unselected population.
B. Total community screening. C. Longitudinal survey.
A. Mass screening of unselected population concerns opening of glaucoma centres for glaucoma-conscious volunteers, who having learnt a little about glaucoma from articles in the press and talks on the radio and T.V., would like to get their eyes tested for the same. With proper propaganda a large coverage can be had for intelligent subjects who care for their eyes. Such subjects will have the patience to get their eyes examined and re-examined periodically if investigations demand. It would be an ideal method but necessarily confined to the urban population in whom the required consciousness for glaucoma could be raised.
B. Total community screening implies a field study of a large population, or of a selected section thereof, that has little access to medical and/or ophthalmic relief centre, as obtains in India. To them are carried a team of ophthalmologists with a peramedical staff equipped with all the instruments, appliances and paraphernalia to carry out the investigations. Such a cumbersome service can only be of value if repeated at least once in two years if not earlier, to discover cases that may have missed detection at an earlier examination and to recheck those who may have been treated medically. Besides, the cost involved would be out of proportion to the value of detecting and treating a condition that accounts for not more than 2% of blindness in this country.
C. Longitudinal survey is essentially a research project in which known cases of glaucoma with their families and siblings are subjected to an exhaustive study over a long period.
In India, a search has therefore to be made to bring to light those elusive cases threatening blindness before it is too late, by a procedure that covers, as vast a population as is possible at an economical rate. This can be achieved on a more convenient and economical scale in hospitals in the highly concentrated urban population, as suggested by COOPER (1966) where a continuous flow of a cross section of all communities from all walks of life is available for examination for the cost of a tonometer and salaries of a couple of assistants.
This has been the object of our study for which the field study was confined to hospital attendances. The lower age limit was kept at 35 years of age as experience in conducting out patient department showed that quite a few cases of proved glaucoma were in persons below 40 years of age.
It seemed best to screen cases in two stages. At first the quickest method was used for preliminary separation of suspects and non-suspects. In the second stage only the suspects were invited for exact diagnosis and final separation into definite glaucoma, suspicious glaucoma and non-glaucomatcus patients. Tonometry with Schiotz tonometer is the best method for this purpose (LEYDHECKER, 1961).
We have carried out this study under 2 groups:
Group A: Where the patients come with ocular distress of some kind i.e. when they are attending the eye department of a hospital.
Group B: Where the patients come for conditions other than ophthalmic, a group that would correspond to random sampling as in field studies, where, the subjects are completely unaware of their condition, as when they attend departments of a hospital, other than the ophthalmic.
Out of 600 subjects screened under Group A, 27 were finally diagnosed as cases of chronic simple glaucoma constituting 4.5% of the cases examined [Table - 2]. HORSELY (1958), and PACKER, LEWIS, OGLESBY and CHEIJ (1959) found the percentage of glaucoma as 4.1 and 6.9% respectively in the same group (eye clinic).
In group B of 400 subjects, 5 were diagnosed as having glaucoma, constituting 1.25%. In the literature, incidence of chronic simple glaucoma varies from 1.3 to 4.6%. The variation may be due to the selection of the age limit as the incidence will be higher if the study is confined to the higher age group, as in the case of PHILIPS (1949) whose study was carried out in a geriatric clinic for ages above 60 years.
The following table compares the findings of various workers:
1. Sortz (1963) ... 1.13 %
2. Reed and Bendor Samuel (1957) ... 1.5%
3. Bendor Samuel, May and Reed (1959) ... 1.8%
4. Phelps (1949) ... 2.5%
Findings of our study are comparable with those of SORTZ (1963), REED et al (1957) and BENDOR SAMUEL et al (1960).
The ratio between incidence of (Group A) and (Group B) patients in the present study is 3.5:1, which is in agreement with those of 3.4:1 reported by PACKER et al (1959).
The incidence of chronic simple glaucoma in Group A is higher because of the more selective nature of this group attending the ophthalmic O.P.D. On the other hand group B represents a random population and the 1.25% of glaucoma in it indicates the percentage of glaucoma cases in a population, that would be missed in the absence of such a mass screening. Although the percentage is small it represents the masked danger of so insidious and malignant a disease as chronic simple glaucoma.
Incidence in Relation to the Age
BLUMENTHAL (1965) and NEUMANN (1965) studied the incidence of glaucoma in age groups ranging from 40 years to above 70 years and 30 years to 70 years and above respectively. Blumenthal reported a rising incidence of glaucoma with increasing age, whereas NEUMANN stated that the incidence of glaucoma increased upto 69 years of age and then started falling.
In the present study the incidence was recorded from 35 years to 70 years and above. It has been observed that there was a rise in the incidence of glaucoma with advancing age [Table - 2]. These findings are in agreement with those of BLUMENTHAL (1965).
NEUMANN did not report a single case of glaucoma in the age group 3039, whereas in this study 2.8% of persons in the age group 35-39 were found to have glaucoma in group A.
SEX
Simple glaucoma was observed more in the male than in the female, the ratio being 54:46 (SMITH, 1965). In the present series the ratio was 53:47. This is in agreement with the findings of the above author. Contrary to the incidence in acute congestive glaucoma the incidence of chronic simple glaucoma is slightly higher in males than in females.
Cupping of the Disc
In the present study, out of 20 eyes showing suspicious fundi and tension ranging between 22.4 to 28.9 mm of mercury, 15 eyes were found to be of definite glaucoma. Thus cases with tension between 22.4 to 28.9 in one or the other eye with suspicious fundus finding should be very carefully investigated as a number of these may turn out glaucomatous.
| Comparative Value of Programmes Under Groups A and B | | |
It would be ideal to screen all the patients that come to the different departments of a general hospital, i.e. group B examination. In this way the coverage is extensive in an urban population which does not involve a great cost-the cost of a good tonometer and the services of a trained technician for preliminary screening. In this way 1.25% of latent glaucoma of which the subject is not conscious gets exposed. The incidence of glaucoma not being higher than about 2% in ophthalmic patients, this uncoverage is considerable at a comparatively low cost. At the same time it would educate the population to become conscious about the health of their own eyes, particularly in respect of an insidious disease like glaucoma. When subjects with suspicious glaucoma were asked to report for a reexamination only 66.6% turned up for the re-examination in both groups. This shows the apathy of the general population towards their own eyes inspite of providing facilities. The value of programme B is offset against this apathy, although the education drive remains to some extent.
Group A programme is conducive of maximum uncoverage at minimum effort i.e. 4.5% of those examined. This figure may not be considered strictly comparable with 1.25% in group B, because some of them actually had glaucoma or had symptoms of glaucoma like headache and defective vision which drove them to take advice regarding their eyes.
The conclusions one can draw are:
1. Whereas it is desirable to get every hospital attendance examined with a tonometer, it is likely that it may be resented by some.
2. The education propaganda of this procedure, supplemented with proper literature propaganda will be considerable in making people glaucoma conscious, although there is the risk of making some subjects glaucoma hysterical.
As tension in 26 glaucomatous eyes, out of 55 eyes (glaucomatous) was on the border line (24.4 mm) routine tonometry should be incorporated in the physical examination of eyes in every case 35 years of age and above, so as to detect glaucoma in early stages and minimise its role as a cause of blindness.
4. Mass screening of rural population regularly spaced is a luxury which India can ill afford considering the results which can be achieved, whereas screening of hospital attendances is a useful form of screening covering a large cross section of a population at a very low cost.
| Summary | | |
The present study comprises of 1,000 subjects, in the age group of 35 years and above for the incidence of simple glaucoma.
The cases were divided into 2 groups. Group A of 600 subjects from a more selected population attending an eye clinic and group B of 400 cases representing an unselected random population not having any eye symptoms. The incidence was 4.5% in group A and 1.25% in group B.
The incidence of simple glaucoma increased with advancing age. Glaucoma was slightly more in males than females 3.3:3.
Results indicate that routine tonometry should be incorporated in the physical examination of eyes in every case 35 years of age and above, so as to detect glaucoma in early stages and minimise its role as a cause of blindness. Such mass screening is most effective and economical in hospital attendances for the benefit of urban populations particularly that attending the eye department of a hospital.[12]
| References | | |
| 1. | BENDOR SAMUEL., D.E.L., MAY, W. and REED, H. (1960): Routine tonometry in 5.000 patients for detection of early glaucoma. Brit. Med. J. 1: 853.  |
| 2. | COOPER. S. N. (1966): Editorial on Glaucoma, J. All-India Ophthl. Soc. 14, 44. |
| 3. | BLUMENTHAL, M. and KORNBLUETH. W. (1965): Survey of glaucoma in Israel. Am. J. Ophthal. 60: 87. |
| 4. | HORSLEY, N. E., LAVIS. P. M. and PACKER, H. (1958): Glaucoma detection in out patients department. J.A. MLA. 166: 1265-69. |
| 5. | KRONFELD, P. C., MC GARRY, H. I. (1948): J.A.M.A., 136: 957. |
| 6. | LEYDHECKER, W. (1961): The techniques and organisation of mass screening for glaucoma. Amer. J. Ophthal. 51: 248. |
| 7. | NEUMANN, E. and ZAUBERMAN, H. (1965): Glaucoma survey in Liberia. Amer. J. Ophthal.. 59: 8-12. |
| 8. | PACKER, H., DEUTSCH, A. R.. LEWIS, P. M., OGLESBY, C. D., and CHEIJ, A. C. (1959): Study of the Frequency and distribution of Glaucoma. J.A.M.A.. 171: 1090. |
| 9. | POLLACK, J. P. (1966): Glaucoma screening, J. of All Ind. ophthal. Soc., 14: 1. |
| 10. | REED, H. and BENDOR SAMUEL, J. E. L. (1957): The detection of glaucoma before evidence of visual impairment. 'Daps. ophthal. Soc. U.K., 77: 379. |
| 11. | SORTZ. L. B. (1963): Experience with active detection of glaucoma amongst the population of Donets Region (in Russian). Vestn. Oftal. 76: 3-33, Quoted from Opthalmic Literature Vol. XVII, Ref. No. 601 (1963). |
| 12. | SMITH, R. J. H. (1965): Clinical glaucoma, Cassell. London P. 10. |
[Table - 1], [Table - 2], [Table - 3], [Table - 4]
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