By Versura, Piera Fresina, Michela; Campos, Emilio C
Abstract Aim. To analyze whether dry eye symptoms and ocular surface parameters change during different phases of the menstrual cycle.
Method. Twenty-nine women of fertile age and with regular, 26-29- day menstrual cycles were included in the study. Fourteen subjects suffered and 15 did not suffer from dry eye symptoms. Symptoms were scored by the validated Ocular Surface Disease Index questionnaire. Tear production was evaluated with the Schirmer I test and the Schirmer II test (Jones test); tear stability with tear breakup time and Ferning test; and degree of dryness by the tear function index and imprint conjunctival cytology. Degree of inflammation was evaluated with conjunctival brush cytology and concentration of exudated serum albumin in tears. Hormonal cytology procedures were applied to exfoliated cells in tears. Patients were analyzed during menstruation, in the follicular phase and the luteal phase over two consecutive cycles, and results were statistically evaluated.
Results. Subjective symptoms, tear production and stability, surface dryness and inflammation were significantly related to hormonal fluctuations in the menstrual cycle. In particular, the impairment of these functions appeared to be related to the estrogen peak occurring during the follicular phase, especially in patients with dry eye.
Conclusion. The ocular surface is confirmed to be an estrogen- dependent unit; clinicians should take into account these cyclic variations during examination of subjects affected by symptoms of eye dryness.
Keywords: Dry eye, menstrual cycle, estrogen, premenstrual syndrome
Introduction
The ocular surface is a functional unit where all components (corneal and conjunctival epithelia, limbal stem cells, tear film, lids, main and accessory lachrimal glands, neural arc connecting the components with trigeminal nervous centers) work together to maintain the optic quality of the eye surface and provide protection for ocular structures [1,2]. Any dysfunction results in inadequate surface lubrication that leads to dryness.
Dry eye is a very common condition that increases in both genders with age, but with higher incidence among females [3] and after the menopause [4], which suggests a role of sex hormones in its onset.
The eye is now recognized to be a target organ for sex hormones [5]; sex steroids also regulate lachrimal and meibomian gland functions in humans over the life span [6,7] . Some issues are still under debate since it is difficult to distinguish the role played by aging or by hormonal excess, deficiency and imbalance [8], although a role for androgens has recently gained increasing scientific evidence [9].
A few incomplete reports have appeared in the past concerning changes of the ocular surface in healthy women still of fertile age, as a consequence of hormonal variations during the menstrual cycle [10-12]. However, to our knowledge, no report dealing with the same changes over the menstrual cycle for women with dry eye has yet appeared in the literature.
The aim of the present work was to analyze the changes occurring in the ocular surface during hormonal fluctuations in young women over the menstrual cycle in both normal and dry eye conditions. The purpose was to understand how hormones may affect ocular surface parameters, while excluding the concurrent role of aging.
Materials and methods
Study participants were 14 women with dry eye symptoms (age 34.7 +- 5.2 years) and 15 women with no symptoms (control group; age 29.2 +- 6.5 years) (mean +- standard deviation). The participants were patients at a day hospital and the laboratory of the ophdialmology unit of the University of Bologna, and the controls were healthy volunteer fellows or students at the university and hospital staff. Exclusion criteria were: contraceptive use of any type; no ocular surface disease for at least 6 months; no systemic disease; no wearing of contact lenses.
The research complied with the Declaration of Helsinki of the World Medical Association, and informed consent was obtained from each subject after a full explanation of the procedures.
Patients were analyzed six times: during menstruation, in the follicular phase (day 11 to 1 6 of die cycle) and in die luteal phase (day 24 to 28 of die cycle) over two consecutive cycles.
Patients were requested to fill in the Ocular Surface Disease Index (OSDI) questionnaire on subjective symptoms, where a score in the range of 0-12 indicates no disability, a score from 13 to 22 indicates light dry eye, a score of 23-32 indicates moderate dry eye, and a score from 33 to 100 indicates severe dry eye [13].
Tear production was assessed widi the Schirmer test, carried out as described elsewhere [14]. Sterile Schirmer strips (ContaCare Ophdialmic Pvt. Ltd., Baroda, India) were placed at the outer lateral inferior candius widi the eyes open and the test performed widiout (Schirmer I test, conducted twice) or widi (Schirmer II test or Jones test) anesthesia (oxybuprocain 0.5%). Padiological value was scored as
Tear stability was assessed by tear breakup time (BUT) performed as described elsewhere [14] (padiological value II/III).
Degree of dryness was evaluated widi the tear function index (TFI) and conjunctival imprint cytology. TFI correlates tear production and drainage and results from the ratio between the Jones test as previously described and the tear clearance rate, graded to the color of fluorescein dye fading compared widi a control staining dilution scale, as described in [17]. A diagnostic ruler estimates TFI 95 indicates a normal eye. Conjunctival impression cytology was performed, processed and scored as described in [18]; the abnormal grade was regarded as > 1.
Degree of inflammation was recorded by brush conjunctival cytology observed and scored as described in [19] (score 0-5: normal; 6-10: light inflammation; 11-20: progressively severe inflammation) and by serum albumin exudated in tears, determined as described in [20] (normal value 0.174 +- 0.028 mg/ml [21]).
Maturation index (MI) of conjunctival cells was assessed by counting the percentages of parabasal (P), intermediate (I) and superficial (S) cells obtained by exfoliative cytology and Papanicolau staining. MI is obtained by assigning the values S= 1, I = 0. 5, P = 0 as described in [22,23] for cells of the vaginal tract, so MI value increases along widi increasing expression of superficial vs. parabasal cells.
Data were analyzed statistically using SPSS 14.0 (SPSS Inc., Chicago, IL, USA) by applying the unpaired Student’s t test (significance was assumed at p
Results
Data collected for the normal subject group are summarized in Table I. The results of all tests were in the normal range, as described in the ‘Materials and mediods’ section. Analysis of the data comparing the outcomes from the diree phases considered in the study protocol provided evidence of fluctuations over the menstrual cycle in some tests, widi statistically significant differences.
In particular, subjective symptoms showed a slighdy increased score in the luteal phase (Figure 1). The MI was also found to follow a cyclic variation over the diree phases (Figure 2). In the follicular phase the BUT exhibited a reduction (Figure 3), the conjunctival imprint cytology (Figure 4a) and brush cytology (Figure 5 a) showed a slight shift to padiological values, and the concentration of exudated serum albumin in tears was found to increase (Figure 5b). For these tests, values in the follicular phase were statistically significandy different compared widi values in the other two phases. No cyclic fluctuations were demonstrated in the normal subject group widi regard to tear production, the TFI (Figure 4b) or tear stability detected widi the Ferning test.
A summary of data collected for the dry eye patient group is given in Table II. The results of the tests were in the padiological range, except for tear production measured by the Schirmer I and Jones tests (Schirmer II) and the Ferning test. Analysis of the data comparing the outcomes from the diree phases showed evidence of fluctuations over the menstrual cycle in all tests except the Schirmer I and Jones tests, widi statistically significant differences.
The worsening of subjective symptoms appeared to be statistically significant in the luteal phase compared widi the other two phases (Figure 1). The MI followed the same cyclic variation over the three phases as shown in normal subjects (Figure 2). A marked reduction of BUT was demonstrated in the follicular phase (Figure 3). A higher degree of dryness was shown in the follicular phase as demonstrated by the increased score of conjunctival imprint cytology (Figure 4a) and decreased TFI value (Figure 4b). In addition, a higher degree of inflammation was evidenced in the follicular phase by the increased brush cytology score (Figure 5a) and the concentration of serum albumin in tears (Figure 5b).
Table I. Summary of the results in the normal subject group.
Figure 1. Ocular surface disease index (OSDI) questionnaire score in normal and dry eye patients during the menstrual cycle. Figure 2. Maturation index (MI) score in normal and dry eye patients during the menstrual cycle.
Figure 3. Tear breakup time (BUT) in normal and dry eye patients during the menstrual cycle.
Discussion
The ocular surface is the interface with the external environment and represents a peculiar condition in the body since it works in the absence of keratinization as a defensive mechanism, in normal conditions. Dry eye syndrome is a frequent disease of the ocular surface; the most common reason for dryness is simply the normal aging process, although several other factors can be advocated, including a role for sex steroids [8,9].
The papers in literature dealing with possible changes of the ocular surface over the menstrual cycle have been reviewed [4,8] and appear to be quite fragmentary since they analyze selected parameters only; on the contrary, the eye surface needs an integrated analysis to fully understand its impairment [14]. The present study was undertaken to understand whether the main ocular surface parameters, taken altogether, change as a function of the menstrual cycle in young women, either in normal conditions or in the presence of subjective symptoms of eye dryness.
Figure 4. (a) Imprint cytology score and (b) tear function index (TFI) score in normal and dry eye patients during the menstrual cycle.
Figure 5. (a) Brush cytology score and (b) serum albumin in tears in normal and dry eye patients during the menstrual cycle.
Table II. Summary of the results in the dry eye patient group.
Patients were recruited on the basis of self-declaration of regular, 26-28-day menstrual cycles and step points were set to establish the three phases regulated by sex steroid hormones. Estrogen is supposed to be the dominant hormone in the follicular phase, spanning from the end of menstruation until ovulation, followed by progesterone being dominant in the luteal phase, which begins at ovulation and lasts until the menstrual phase of the next cycle, when both estrogen and progesterone are believed to be at their lowest levels in plasma.
Serum hormone testing was not carried out because of the invasiveness of peripheral blood collection in patients where this procedure would not have been ethically correct to perform. We evaluated the MI as a non-invasive technique to assess whether a cyclic fluctuation was present, and patients were also evaluated by means of the non-painful techniques adopted by our service in the daily analysis of ocular surface condition [19]. The degree of maturation of conjunctival smears taken from menstruating women, expressed through the MI, has been demonstrated to exhibit changes related to hormonal variations during the menstrual cycle, synchronous with reproductive tract epithelia [1O]. Exfoliated conjunctival cell types when expressed as a percentage of total cells form the MI: a pattern of predominantly parabasal cells is typical of an atrophie situation as occurs in the postmenopausal state or childhood, a pattern of predominantly intermediate cells is characteristics of progesterone’s effect in the postovulatory phase, and estrogen stimulation produces superficial cell dominance characteristic of the follicular phase. Our data from both normal and dry eye subjects demonstrated that MI fluctuation was present in the cycle, in agreement with others [10], and further confirmed that conjunctiva is an estrogen-sensitive epithelium. This finding also allowed us to correlate the other data to hormonal status with reasonable confidence.
Some components of the ocular surface system were demonstrated not to be influenced by hormonal fluctuations, maintaining the same levels during the cycle. These were tear film production and tear stability as shown by the Ferning test, in agreement with previous authors [11,12].
Subjective symptoms in both normal and dry eye subjects exhibited a slight, but statistically significant increase of score in the luteal phase. This finding would suggest to include eye dryness among the various physical, mental and behavioral symptoms tied to a woman’s menstrual cycle and named the ‘premenstrual syndrome’ (PMS). By definition, symptoms occur during the days before a woman’s period starts and they usually disappear after the first day of flow. PMS is a complex health concern; up to 80% of women experience some symptoms of PMS and physicians still debate its cause and the possible therapy [24].
Tear stability as detected by BUT appeared affected by the estrogen peak in the follicular phase, as we found a significant decrease in both normal and dry eye subjects. This finding does not agree with previous authors who had denied a direct estrogen receptor role on BUT [25] but demonstrated a recovery of BUT after estrogen-based hormone replacement therapy in postmenopausal women [26]. Tear BUT is strictly related to lipid profile secreted by meibomian glands [27] , a process known to be regulated by androgens [28] . The decrease of BUT in our patients could possibly be related to the supposed role of estrogen, with particular reference to 17 beta-estradiol, in the upregulation of proinflammatory cytokines [29] that leads to subclinical inflammation accounting for the decrease of tear stability [3O].
Imprint cytology scores conjunctival surface dryness by analyzing the density of goblet cells and the ratio of superficial epithelial cells [18]; the score increases with goblet cell loss and the increase of superficial cells, with higher score indicating heavier dryness. In both groups an increase was demonstrated in correspondence with the follicular phase, more expressed in dry eye patients, and in agreement with the cyclic fluctuation also evidenced by MI, as discussed above. This finding also could therefore be related to the influence of estrogen on the maturation cycle of conjunctival cells [23], a tissue found to be a target for sex steroid hormones [31].
The TFI introduces an extended way to measure tear flow combined with tear drainage, and gives a practical measure to diagnose dry eye [17] because a lower index indicates heavier system flow/ drainage impairment. We did not find any cyclic variation of TFI value in normal subjects but demonstrated a significant decrease in the follicular phase among the dry eye patients. Since tear production had not been changed, we could argue that TFI changed due to defective drainage, in some way delayed by estrogen influence. Delayed tear clearance can result in an accumulation of irritant factors which can worsen ocular surface disorders either by causing an unstable tear film or by direct effect on the ocular surface epithelium. The role of sex hormones, estrogen in particular, in this issue could be mediated through the regulation of mucin peptides which promote tear outflow in the nasolachrimal duct cells [32].
The condition of ocular surface inflammation also exhibited a worsening during the follicular phase; both brush cytology score and serum albumin exudated in tears showed a marked increase, more expressed in dry eye patients. In fact, dry eye is an inflammatory- based condition [33] and our finding could be set in relation to the supposed role of estrogen in the regulation of proinflammatory cytokines and the overexpression of inflammatory genes in corneal epithelial cells, as already reported [25].
In conclusion, to our knowledge this is the first comprehensive report on the modifications of ocular surface parameters in normal and dry eye women of fertile age, as a consequence of the hormonal variations occurring during the menstrual cycle. Our data show that subjective symptoms, tear production and stability, surface dryness and inflammation significantly follow hormonal fluctuations in the menstrual cycle. In particular, the impairment of several functions appeared to be related to the estrogen peak occurring during the follicular phase, especially in dry eye patients. In this group, in fact, the concurrent chronic inflammation leading to dryness may strengthen the evidence of estrogen’s role in the upregulation of proinflammatory products in tears.
Ophthalmologists should take into account these cyclic variations during examination of subjects affected by symptoms of eye dryness. Gynecologists should consider that, besides aged patients, even menstrual disorders in young women might affect the ocular surface.
Acknowledgement
This work was supported in part through a grant from the Fondazione Cassa di Risparmio in Bologna to E.C.C.
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This paper was first published online on iFirst on 30 July 2007
PIERA VERSURA, MICHELA PRESINA, & EMILIO C. CAMPOS
Department of Surgical Science and Transplants, Section of Ophthalmology, Alma Mater Studiorum
Universita di Bologna, Bologna, Italy
(Received 15 March 2007; revised 18 March 2007; accepted 19 March 2007)
Correspondence: P. Versura, Dipartimento ‘A. Valsalva’, Sezione Oftalmologia, Alma Mater Studiorum Universita di Bologna, Policlinico S. Orsola, Via Massarenti 9, 40138 Bologna, Italy. Tel: 39 051 6364646. Fax: 39 051 341450. E-mail: [email protected]
Copyright Taylor & Francis Ltd. Jul 2007
(c) 2007 Gynecological Endocrinology. Provided by ProQuest Information and Learning. All rights Reserved.
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