Bubella, Raffaella Morreale MD, PhD; Bubella, Daniele Morreale MD, PhD; Cillino, Salvatore MD, PhD
During the last few years, studies regarding the etiology of open-angle (chronic) glaucoma (OAG) have led to the identification of several risk factors, divided into high, moderate, and low. Until recently, stress has been considered of little importance, although several studies1–6 have reported that an increase in the intraocular pressure (IOP) occurs during conditions of physical or mental stress, both in healthy subjects and in those affected by OAG.
Traditional studies by Framingham, in contrast, have confirmed that behavioral patterns and emotional expression may as well be the risk factors for the development and/or progression of a disease; this occurs in type A subjects, on the basis of Friedman and Rosenman classification,7 where coronary damage may depend on the fact that response to stress is stronger and more prolonged.
As in cases of ischemic heart disease, stress in patients with OAG may lead to a greater and more prolonged increase in IOP, especially in type A subjects, and a further stimulus of the process of disease development notwithstanding all attempts at treatment.
The aim of our study is to evaluate the presence of type A behavior in patients affected by OAG and the possible role of psychophysiological situations of stress as OAG risk factors.
MATERIALS AND METHODS
The study involved 50 patients, 30 women and 20 men, affected by OAG, with no significant differences in disease duration, who were observed in the Glaucoma Clinic of the Ophthalmological Institute of Palermo University. We have chosen all patients that have been visited in our center within the space of 3 months.
The mean age of the patients was 63.42±12.9 years with no particular differences between the sexes.
The patients were undergoing treatment with β-blockers and/or prostaglandins and/or carbonic anhydrase inhibitors.
The study was conducted on the basis of the ethical standards laid down by the Declaration of Helsinki and informed consent was obtained from all subjects.
The patients underwent:
- Complete biomicroscopic examination.
- Tonometry and daily tonometric curve.
- Examination of the visual field by means of the computerized perimeter “Octopus 1-2-3” and its evaluation by means of the Glaucoma Staging System 2 (GSS2). We have chosen this staging method because it is quick and easy.8
- Morphologic monitoring of the retinal nerve fiber layers with GDx VCC.
- The use of the Hamilton Anxiety Rating Scale to assess the presence of anxiety and its level.
- Type A/B personality questionnaire (version modified by the Jenkins Activity Survey):
- Ercta-B test for further personality evaluation of type A subjects.
- Test of psychic distress: IGD questionnaire to assess the level of this and of the psychopathologic symptoms together with levels of self-esteem, extroversion, and the distress level.
- State-Trait Anxiety Inventory test (STAI test).
- Brief-cope test.
- Life event.
Psychological tests were performed, validated, and administered by the same psychologist.
The data are expressed as mean±SD.
Variance analysis (ANOVA) and the Student t test were used for the evaluation of data significance.
The correlations between the visual field involvement along with the use of the Brief-cope scale were examined by means of linear regression analysis and expressed as Pearson correlation coefficient (r).
Values of P<0.05 were considered as significant.
Sixty-four percent of the patients, 17 women and 13 men, showed type A behavior. The anxiety test showed that 50% of the group, 11 women and 4 men, presented a state anxiety, which exceeded the cutoff point and that this was different in the 2 sexes, with higher levels in the women (P=0.03).
Fifty-four percent of the subjects examined also showed a trait anxiety, which exceeded the cutoff point. Both trait and state anxiety proved to be more evident in type A subjects (P=0.001.)
IOP in type A patients was 20.2±2.57 mm Hg (range, 16 to 27 mm Hg) and in type B patients was 20.4±1.59 mm Hg (range, 18 to 25 mm Hg).
The daily tonometric curve (Fig. 1) shows that in subjects with type A personality there are greater fluctuations.
Study of the visual field showed involvement at GSS2, which was more significant (P=0.001) in type A (2.65±0.83) compared with that in type B subjects (1.55±0.97).
Subjects with perimetric damage grading at GSS2 of ≥2 presented a higher level of situation anxiety with no difference between the sexes, whereas this was higher in women, although not significantly, when this damage was ≤2.
With the Brief-cope scale, visual field involvement showed a significant negative correlation (P=0.024).
The GDx VCC examination showed that, although the TSNIT values were within the normal range (45.6 to 66.8), they proved to be higher (P>0.001) in type B subjects, who, in fact, showed a mean value of 59 compared with the 53 observed in type A subjects.
On the contrary, the NFI index was higher in type A subjects (P=0.01), where the mean value was 40 (range, 34 to 52) compared with the value of 35 (range, 30 to 43) observed in the type B subjects.
During the last decade several theories have been proposed with regard to the role played by fluctuations of IOP in the progression of glaucomatous damage. The AGIS study9 reports that fluctuations of >3 mm Hg present an additional risk factor for OAG. Little attention has been paid to the role that stress might play in favouring such fluctuations, although several studies have reported an increase in IOP subsequent to physical and/or mental distress in patients with no ocular disease6 and with OAG.1,2,4,5 Although the IOP increase in these studies is generally a little higher than 3 mm Hg, in older subjects, as reported by Recupero and colleagues, it may be significantly higher.
Reports in the literature confirm the link between personality, stress (both acute and chronic), and cardiovascular disease and that type A behavior, according to Friedman and Rosenman’s classic definition, exposes the subject to negative stress effects with a higher and more prolonged pressure response.10 Bakke et al11 have shown that during isometric exercising there is an agreement between the blood pressure and the IOP.
The frequent daily oscillations of blood pressure observed in type A subjects can also be seen at the ocular level, with IOP fluctuations that most certainly present an increased risk of damage to the visual field.12,13 We have found that in the type A behavior subjects there are several fluctuations in the daily tonometric curve with a range of about 7 mm Hg, which could be the cause of the more evident field defects.
Study of the visual field in our 30 type A subjects showed a clearer and more significant involvement. The TSNIT index of GDx VVC, although still within normal range, was lower in these patients, which might be because of their more frequent IOP fluctuations observed by means of the daily tonometric curve. Furthermore, these subjects present clear signs of both trait and state anxiety, which makes them more stress-sensitive. In patients with perimetric damage of ≥2, trait anxiety is generally higher with correspondingly more marked IOP oscillations.
Our own data agree with those already published by Mabuchi et al,14 who report that in a group of 230 patients with OAG they observed a prevalence of subjects with anxiety and/or depression compared with subjects without ocular problems or with cataract.
Furthermore, by means of the stimulation of the neuroendocrine system and resulting activation of the sympathetic nervous system, stress leads to an increase of catecholamine secretion with vasoconstriction and an increase in vascular resistance and a rise in blood pressure levels. It is well known that there exist catecholamine receptors within the ophthalmic artery and in the extraocular portion of the central retinal artery, and the consequent increase of these mediators may lead to a more intense and prolonged vasoconstriction. Bonomi et al15 have suggested that “high blood pressure may alter perfusion, thus increasing the peripheral resistance of the small blood vessels, such as those supplying the proximal portion of the optic nerve.”
The concurrence of these 2 conditions, that is, an increase in daily IOP fluctuations and high-pressure insult with reduced optic nerve perfusion, might well explain the clearer damage of the visual field observed in our own subjects with type A behavior.
In conclusion, although with the necessary caution required by our limited number of subjects, our data permit us to suggest that:
- Personality study could be an important element in the diagnosis and treatment of OAG as, at least in our own group, the prevalence of type A subjects proved to be extremely high (64%).
- Subjects with type A behavior present a higher level of perimetric damage, which proves to be associated with maladjusted management methods of the stress situation and higher levels of anxiety compared with those observed in type B behavior subjects.
- In the type A subjects, the TSNIT mean, although still within the normal range, was lower and, on the contrary, the NFI index was higher compared with those observed in the type B subjects.
It is therefore absolutely indispensable to perform the necessary follow-up to evaluate the possible evolutionary differences in the glaucomatous damage within the 2 groups; this is the only way of identifying the real role played by stress in the pathogenesis and evolution of OAG.
The authors thank L. Ferraro (Section of Psychology, Department of Experimental Biomedicine and Clinical neuroscience, University of Palermo, Palermo, Italy) for psychological evaluation of patients in this study.
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