«Working paper Gender Diferentials in the Seeking of Eye Care Rajshri Jayaraman Debraj Ray Shing-Yi Wang April 2013 GENDER DIFFERENTIALS IN EYE CARE: ...»
in the Seeking
of Eye Care
GENDER DIFFERENTIALS IN EYE CARE: ACCESS AND TREATMENT
European School of Management and Technology, Berlin
New York University, New York
The Wharton School, University of Pennsylvania, Philadelphia
April 23, 2013
Background A central feature of many developing countries is the presence of signiﬁcant gender differentials in health outcomes. We study one potential factor which can account for this; namely, that females seek treatment later than males, and contrast this pathway with the hypothesis that females receive differential care at the medical facility.
Methods We examine gender differentials in the seeking and treatment of eye care. We study diagnostic and surgical outcomes using a unique dataset comprising a sample of 60,000 patients who sought treatment over a 3-month period in 2012 at the Aravind Eye Hospital in India. We distinguish between symptomatic and asymptomatic illness.
Findings At the time of presentation to an eye care facility, women have worse diagnoses than men across all available indicators of symptomatic illness. They have lower visual acuity and pinhole visual acuity, are more likely to be sight-impaired, and are more likely to be advised surgery or diagnosed for cataract.
In contrast, males and females do not differ signiﬁcantly in their “best corrected visual acuity and there are no gender differences in other indicators of surgical care – time to surgery, surgery duration, the incidence of post-operative complications, and the seniority of attending medical personnel. For asymptomatic disease, there is no signiﬁcant difference between males and females: intraocular eye pressure and a high cup-to-disk ratio, which are correlates of glaucoma, are not signiﬁcantly different across gender.
Interpretation The ﬁndings for symptomatic illness suggest that women seek treatment later than men for perceptible illness. That no such gender differential exists for asymptomatic disease suggests that women do not necessarily go for preventive checkups at a lower frequency than men. We ﬁnd no systematic evidence that women and men receive differential medical treatment.
Funding International Growth Center.
Acknowledgements We are very grateful to the staff of Aravind Eye Hospital, in particular Ganesh Babu and R.D. Thulsiraj. We also thank Abraham Holland and Misha Sharma at the center for Microﬁnance for providing invaluable local project management, Amelie Schiprowski for excellent research assistance, and Dr. Tomasz Mlynczak for his medical expertise.
1. INTRODUCTION A central feature of many developing countries is the presence of signiﬁcant gender differentials in health outcomes. The most dramatic evidence of this is excess female mortality, captured in the suspiciously low ratio of women to men, notably in India and in China (1; 2). This excess mortality is not simply conﬁned to newborns (or pre-natal selection by gender) and infants. Recent research by Anderson and Ray (3; 4) as well as the 2011 World Development Report (5) highlight the following facts: (i) The bulk of excess female mortality in India and sub-Saharan Africa is at older ages, not just birth, infancy and early childhood as previously emphasized (6; 7; 8; 9; 10; 11; 12); and (ii) Almost all the “missing women” stem from disease-by-disease comparisons and not from the changing composition of disease as described by the epidemiological transition. This suggests that gender bias in health outcomes is pervasive, spanning several age groups and a variety of diseases.
Presumably, there are numerous underlying pathways for these discrepancies, ranging from differential care at home to differential medical care once treatment is sought, not to mention a plethora of other intervening factors, such as diet, stress and occupational structure. The main objective of this paper is to study just one possible factor, but a fundamental one; namely, that females seek treatment later than males. We also brieﬂy contrast this pathway with the hypothesis that females receive differential care at the medical facility. We do this by examining gender differentials conditional on seeking eye care in an Indian hospital.
Three factors motivate our focus on eye care. First, there is the intrinsic importance of vision, a matter that directly impinges on productivity and well-being. But, of course eye care is not alone in this regard.
The second factor — and in this respect eye disease is truly distinct — is that different aspects of it, such as visual acuity, myopia, cataract onset or glaucoma, are measurable with relatively high precision. Using these objective measures of disease intensity, it is possible to evaluate the extent to which eye health has deteriorated at the time of seeking care. Third, some eye diseases are perceived as they evolve, while others are not. The most obvious example of a symptomatic disease is, of course, the deterioration of visual acuity: loss of acuity is immediately and directly linked to the perception of that deterioration. This is certainly true of deteriorations that require corrective lenses, but it is also true for conditions such as cataract. On the other hand, conditions such as glaucoma are asymptomatic until the disease has reached an advanced stage.
In principle, then, we can distinguish between two notions of gender-based neglect in seeking medical care. One is that females do not go for regular, preventive checkups at the same frequency as males, in which case we would expect to see across-the-board discrepancies in the severity of illness (conditional on presentation at a care facility) irrespective of the symptomatic nature of the disease. On the other hand, if there is gender-based delay only in responding to the perceptible onset of illness, then we should expect to observe gender differences in disease progression at the time of presentation for symptomatic diseases, but no such differences for asymptomatic diseases.1 To a large extent, the data we have allows us to do just that.
We summarize our ﬁndings. At the time of presentation to an eye care facility, women have worse diagnoses than men across all available indicators of symptomatic illness. They have lower visual acuity It is important to appreciate that as far as symptomatic disease is concerned, the above approach is valid independent of whether the incidence of the disease in question varies systematically across males and females, as long as the perception of disease is gender-independent.
and pinhole visual acuity, they are more likely to be sight-impaired, and are more likely to be advised surgery or diagnosed for cataract.2 In contrast, males and females do not differ signiﬁcantly in their “best corrected visual acuity and there are no gender differences in other indicators of surgical care – time to surgery, surgery duration, the incidence of post-operative complications, and the seniority of attending medical personnel.3 For asymptomatic disease, there is no signiﬁcant difference between males and females: intraocular eye pressure and a high cup-to-disk ratio, which are correlates of glaucoma, are not signiﬁcantly different across gender.
Sample. We use data from the Aravind Eye Hospital (or Aravind, as we refer to it hereafter) — an extraordinary network of eye-care facilities based in Madurai, India. Aravind has four main channels of service provision in the region: ﬁeld camps which are set up on an ad hoc basis (usually over weekends) in rural areas, vision centers, which are brick-and-mortar facilities located in semi-rural areas, and two state-of-the-art hospitals located in the city of Madurai, one of which is heavily subsidized, and the other which provides services at market rates. The volume is enormous: close to a million patients, on average, have been served every year for 36 years. The economic philosophy of Aravind, one that uses high-end facilities in medical care to subsidize more spartan approaches, without stinting in any way on the medical care itself, has been much studied in both developed and developing countries as a business model (several case studies of Aravind exist, including one developed at the Harvard Business School).
Our database of over 60,000 patients is drawn from Aravind’s Madurai district catchment area, collected between May and August of 2012. The database spans the paid hospital and subsidized hospital in the district capital, Madurai, as well as numerous vision centers and eye camps that operated in the region over this period. Speciﬁcally, we have medical information on: (i) the population of 13,422 new outpatients arriving at vision centers between June–August, recording the initial diagnosis as well as any vision corrections that were made; (ii) a random sample of 16,155 new outpatients arriving at ﬁeld camps, the paid hospital and the subsidized hospital between May–July, recording the initial diagnosis as well as any vision corrections that were made; (iii) the population of 29,591 cataract patients, whose surgeries were performed in the paid and subsidized hospitals between June–August, recording the details of the surgical procedure that was followed, as well as subsequent follow-up; and (iv) a subsample of 1000 glaucoma patients, who ﬁrst registered between 2007–2010.
Measures of Illness. The varied nature of this data allows us to put together different measures of eye conditions, and study gender discrepancies in each of them. Using the ﬁrst two groups of measures outlined below, we examine whether symptomatic visual impairments and eye disease are more severe for women than men at the time of presentation. If so, then women are likely to be seeking treatment later than men. The third group of measures, corrective procedures, allows us to investigate gender differentials in medical treatment. The fourth group of measures, pertaining to asymptomatic ocular disease, permit us to explore gender differences in general (or preventive) eye care.
There is a small literature that studies gender bias in children’s access to care in India; see, e.g., (21; 22; 23). These papers ﬁnd that families are more likely vaccinate boys relative to girls, travel longer distances for their care, and incur larger expenditures for them. Such biases are entirely consistent with our ﬁndings.
Unequal or prejudicial treatment at the medical facility has received signiﬁcant attention in high-income societies (13; 14;
15; 16; 17; 18; 19; 20).
1. Visual Acuity. This is a measure of the ability to see. Visual acuity is measured for all outpatients using the Snellen Tumbling-E eye chart. We convert this measure into a continuous variable with range [0, 1], where 1 is perfect (i.e. 6/6 or 20/20) vision and 0 corresponds to cases in which, at best, only hand movement, ﬁnger counts or light could be perceived. Our measure can be roughly interpreted as the relative distance at which the patient would have to be located in order to see as clearly as a person with perfect vision.
2. Other Symptomatic Ocular Disease. Cataract is a clouding of the eye lens typically manifested at later ages (50+). As in more routine vision problems that need correction, cataract is symptomatic except perhaps in its earliest stage. Outpatients are routinely examined by ophthalmologists who diagnose cataract and advise surgery. This information can be coded as binary variables: e.g., surgery advisement is captured by a variable equal to 1 if surgery was advised and 0 if it was not advised. Pinhole visual acuity, which is an additional indicator of centrally located, advanced cataract, is also recorded. Our measure of pinhole visual acuity is constructed in an analogous manner to visual acuity.
3. Treatment. We look at several indicators connected to the actual treatment received. We record best corrected vision, which is visual acuity measured after refractive correction, as well as pinhole visual
acuity following cataract surgery. We use three measures of medical treatment of cataract surgery patients:
the time elapsed in minutes between hospital admission and surgery for patients who were operated on the same day as admission, surgery duration in minutes, and the surgeon’s medical qualiﬁcations. We note if the cataract surgery patient spent at least one night in the hospital prior to the operation. Finally, we have two measures of cataract patient follow-up: whether or not there were post-operative complications and whether or not the patient came later than their instructed post-operative appointment, typically scheduled for one month following the operation.
4. Asymptomatic Ocular Disease. We study glaucoma, an eye condition resulting in damage of the optic nerve, which is asymptomatic until quite advanced, upon which it leads to progressive and irreversible loss of vision, typically proceeding from the periphery inwards. The early stages of glaucoma are highly correlated with the results of different tests, such as the measurement of cup-to-disc ratio, scores on a visual ﬁeld test and intra-ocular eye pressure. It is not unusual to ﬁnd glaucoma in a patient who seek care for something else entirely, perhaps a routine check-up or because of some other complaint.
Statistical Analysis. We examine gender differentials in outcomes for each of the variables described
above by estimating the following regression model: