An association between hypothyroidism and primary open-angle glaucoma

Intermittent Fasting and Vitamin E Supplementation Attenuates Hypothyroidism-Associated Ophthalmopathy

Visualization is a complex-integrated procedure of the eyes and brain that allows to see this colorful world. Hypothyroidism-associated ophthalmopathy (HAO), often known as dry eyes, swelling around the eyes, blurred vision, glaucoma, and cataracts, are some eye-related issues caused by hypothyroidism. Yet there is no permanent cure for hypothyroidism; taking medicine throughout life is the only solution to keep its harmful effects under control. This study used intermittent fasting (IF) and vitamin E (Vit.E) supplementation to prevent hypothyroidism-associated ophthalmopathy. This study hypothesized that intermittent fasting-like diet regimens and vitamin supplementation should reduce the propagation of HAO by its antioxidant potential. In the present study, experimental animals are divided into five groups: normal, hypothyroidism control, dual, Vit. E, and IF. Hypothyroidism is generated in the experimental groups by taking propylthiouracil (PTU) for 24 days while also taking IF and Vit. E supplements. The hypothyroid-induced experimental animals demonstrated an increase in IOP and lipid peroxidation while thyroid hormone levels depicted a massive decline which is a clear denotation of the effects of the thyroid on eyes and lifestyle. Ancient Ayurveda inspires these proposed therapies and has successfully reduced all the damage to the thyroid gland and the eye.

Subclinical hypothyroidism and anti-thyroid peroxidase antibodies in primary open-angle glaucoma: A case-control study

PURPOSE

To evaluate the association among subclinical hypothyroidism, anti-thyroid peroxidase (anti-TPO) antibody, and primary open-angle glaucoma (POAG).

STUDY DESIGN

Case-control study.

METHODS

The cases consisted of patients with POAG and controls were age- and sex-matched patients from the general eye clinic with no history of glaucoma. Blood samples were taken from the participants' antecubital veins and sent for measurement of thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and anti-thyroid peroxidase (anti-TPO) antibody. Data was analyzed using the Mann-Whitney U test and the Chi-square test. Odds ratio with 95% confidence interval (CI) was calculated. A two-tailed P value less than 0.05 was considered for statistical significance.

RESULTS

There were a total of 63 cases and 63 controls. Subclinical hypothyroidism was present in 20.6% of patients in the glaucoma group and 4.8% of patients in the control group ( P < 0.01). The odds of subclinical hypothyroidism in patients with POAG compared to controls was 5.2 (95% CI 1.7-22). Anti-TPO antibody positivity was higher in the glaucoma group (22.2%) than in the control group (14.3%), but this did not reach statistical significance ( P = 0.25).

CONCLUSION

This study suggests an association between POAG and subclinical hypothyroidism. Further research is needed to establish the cause-and-effect relationship between these two conditions.

Changes in Intraocular Pressure and Corneal and Retinal Nerve Fiber Layer Thicknesses in Hypothyroidism

Purpose

To evaluate the changes in intraocular pressure (IOP), corneal thickness (CT), and retinal nerve fiber layer thickness (RNFLT) in patients with hypothyroidism before and after treatment.

Methods

A complete ophthalmic examination including visual acuity, IOP, anterior segment, and fundus examination together with CT and RNFLT measurements were performed for each patient with newly diagnosed hypothyroidism, at the initial diagnosis and the third and ninth months of the L-thyroxine treatment. Wilcoxon signed rank test and Spearman's correlation test were used for statistical evaluation of the results.

Results

A total of 56 eyes of 28 patients were included in the study. The mean IOP and CT values were found to decrease with medical treatment (p=0.000). There was no significant change in any of the RNFLT parameters measured with scanning laser Polarimeter after L-thyroxine treatment (Wilcoxon, p>0.05). The change in IOP levels was not correlated with the change in thyroid hormone levels (Spearman's correlation test, p>0.05). The mean increase in serum free T3 and serum free T4 levels and the mean decrease in serum TSH levels at the ninth month of the therapy were found to be correlated with the decrease in CT in the left eyes (Spearman's correlation test, R>0.4 and p<0.05).

Conclusions

Hypothyroidism seems to cause a reversible increase in CT and IOP. IOP changes may be secondary to CT changes. RNFLT parameters measured with scanning laser Polarimeter do not seem to be affected by hypothyroidism. When the CT is taken into account and the IOPs corrected for CT, the prevalence of glaucoma in hypothyroidism may not be as high as previously reported. This issue should be taken into account while assessing glaucoma in patients with hypothyroidism.

The interrelation between hypothyroidism and glaucoma: a critical review and meta-analyses

Data on the association between hypothyroidism and glaucoma are conflicting. We sought to shed light on this by conducting a critical review and meta-analyses. The meta-analyses were conducted in adherence with the widely accepted MOOSE guidelines. Using the Medical Subject Heading (MeSH) terms: hypothyroidism, myxoedema and glaucoma or intraocular pressure, case-control studies, cohort studies and cross-sectional studies were identified (PubMed) and reviewed. Using meta-analysis, the relative risk (RR) of coexistence of glaucoma and hypothyroidism was calculated. Based on the literature search, thirteen studies fulfilled the inclusion criteria and could be categorized into two groups based on the exposure. The designs of the studies varied considerably, and there was heterogeneity related to lack of power, weak phenotype classifications and length of follow-up. Eight studies had glaucoma (5757 patients) as exposure and hypothyroidism as outcome. Among these, we found a non-significantly increased risk of hypothyroidism associated with glaucoma (RR 1.65; 95% confidence interval [CI]: 0.97-2.82). Based on five studies (168 006 patients) with hypothyroidism as exposure and glaucoma as outcome, we found the risk of glaucoma to be significantly increased (RR 1.33; 95% CI: 1.13-1.58). Based on these meta-analyses, there seems to be an association between hypothyroidism and glaucoma, which does not seem to be the case between glaucoma and hypothyroidism. However, larger scale studies with better phenotype classification, longer follow-up and taking comorbidity and other biases into consideration are needed to address a potential causal relationship.

Hypothyroidism as a risk factor for open angle glaucoma: A systematic review and meta-analysis

PURPOSE

The relationship between hypothyroidism and primary open angle glaucoma (POAG) has attracted intense interest recently, but the reported results have been controversial. This meta-analysis was carried out to determine the association between hypothyroidism and POAG.

METHODS

The literature was identified from three databases (Web of Science, Embase, and PubMed). The meta-analyses were performed using random-effects models, with results reported as adjusted odds ratios (ORs) with 95% confidence intervals (CI 95%).

RESULTS

A total of 11 studies meeting the inclusion criteria were included in the final meta-analysis. The pooled OR based on 11 risk estimates showed a statistically significant increased risk of POAG prevalence among individuals with hypothyroidism (OR = 1.64, 95% CI = 1.27-2.13). Substantial heterogeneity among these studies was detected (P < 0.001; I2 = 83.2%). Sub-group analysis revealed that the cohort studies and case-control studies showed a significant association between hypothyroidism and POAG, which was not observed in cross-sectional studies. There was no significant publication bias in this study.

CONCLUSIONS

The findings of this meta-analysis indicate that individuals with hypothyroidism have an increased risk of developing POAG.

Glaucomatous Optic Nerve Changes and Thyroid Dysfunction in an Urban South Korean Population

Purpose. This study was performed to evaluate the relationship between intraocular pressure (IOP) and glaucomatous optic nerve change and thyroid factors in Korean population. Materials and Methods. The study included subjects who underwent health screening in Kangbuk Samsung Hospital. Detailed history taking and systemic and ocular examination including fundus photography were performed for all participants. All fundus photographs were divided into two groups based on disc and RNFL appearance: nonglaucoma and glaucoma group. Subjects were also divided into quartiles of each thyroid function parameter, and the relationship with IOP and glaucoma were analysed. Results. In univariate analysis, free T4, T3, and TSH in normal subjects and T3 in thyroid disease group were associated with the IOP. After adjusting for age and sex, the IOP tended to slightly decrease according to the level of the quartile of free T4 and T3 in normal subjects. In terms of glaucoma, on multivariate analysis, it did not show a significant correlation with any thyroid function tests. Conclusions. In normal subjects, the IOP tended to be decreased according to the level of free T4 and T3 but the amounts were clinically insignificant. Thyroid factors are not an independent risk factor for the development of glaucoma.

Investigation of the choroidal thickness in patients with hypothyroidism

Purpose:

The effect of hypothyroidism on the choroidal thickness (CT) was investigated in patients with subclinical hypothyroidism and overt hypothyroidism, and biochemically and clinically euthyroid patients receiving levothyroxine treatment. The patients were compared with healthy subjects.

Materials and Methods:

One eye of 71 hypothyroid and 22 healthy subjects between 20 and 40 years of age were included in this study. CT measurements were taken at the fovea and at 2 points that were 1500 μm nasal and temporal to the fovea using spectral-domain optical coherence tomography. Independent sample t-test's and was used for statistical analysis of the data.

Results:

The CT was significantly thicker in hypothyroid patients compared to healthy subjects (P values were 0.013 for subfoveal, 0.015 for temporal and 0.020 for nasal segments). The intraocular pressure (IOP) and body mass index (BMI) were also significantly higher in hypothyroid patients (P values were 0.021 and 0.003, respectively). There was not a statistically significant difference in the BMI and IOP measurements between healthy subjects and euthyroid patients (P > 0.05). However, there was a statistically significant difference in the subfoveal, temporal and nasal CT measurements between healthy subjects and euthyroid patients (P values were 0.006, 0.031 and 0.013, respectively).

Conclusions:

All subgroups of hypothyroid patients had thicker CT compared to healthy subjects. Euthyroid patients receiving levothyroxine treatment had lower IOP, BMI levels, and serum lipid levels than patients with subclinical hypothyroidism and overt hypothyroidism.

Risk Factors for Primary Open Angle Glaucoma (POAG) Progression: A Study Ruled in Torino

Purpose:

Aim of this retrospective, observational study is to describe features of a population sample, affected by primary open angle glaucoma (POAG) in order to evaluate damage progression on the basis of the emerged individual risk factors.

Methods:

We included 190 caucasian patients (377 eyes), evaluating relationship between individual risk factors (explicative variables) and MD (Mean Deviation) of standard automated perimetry. We also considered the dependent variable NFI (Neural Fiber Index) of GDx scanning laser polarimetry. Progression has been evaluated through a statistic General Linear Model on four follow up steps (mean follow up 79 months).

Results:

Factors reaching statistical significance, determining a worsening of the MD variable, are: age (P<0.0001), intraocular pressure (IOP) at follow up (P < 0.0001), female gender (P<0.0001), hypertension (P< 0.0001) and familiarity (P = 0.0006).

Factors reaching statistical significance, determining a worsening of the NFI variable, are only IOP at follow up (P = 0.0159) and depression (P = 0.0104).

Conclusion:

Results of this study confirm and enforce data coming from most recent studies: IOP remains the main risk factor for glaucoma assess and progression; age and familiarity are great risk factors as underlined in the last decades; female sex can be an important risk factors as emerged only in the last years; arterial hypertension should always be evaluated in timing of our clinic follow up.

Hypothyroidism and Glaucoma in The United States

PURPOSE

To investigate the association between hypothyroidism and glaucomatous disease.

METHODS

This cross-sectional study included all subjects above the age of 40 years from two nationwide surveys: the 2008 National Health Interview Survey (NHIS) as well as the 2007 and 2008 National Health and Nutrition Examination Survey (NHANES). The presence or absence of glaucoma, thyroid disease and other demographic and health-related information including comorbidities was ascertained via interview. Blood samples were collected from NHANES subjects and analyzed for thyrotropin (TSH).

RESULTS

A total of 13,599 and 3,839 NHIS and NHANES participants respectively were analyzed to assess for a possible relationship between self-reported glaucoma, and self-reported hypothyroidism as well as self-reported thyroid disease. The unadjusted odds ratio (OR) for NHIS showed a significant association between self-reported glaucoma and self-reported hypothyroidism (OR 1.46, 95% confidence interval [CI] 1.07-1.99). Multivariate logistic regression analysis adjusted for age, gender, race, comorbidities, and health-related behavior, however, showed no association between self-reported glaucoma and hypothyroidism or thyroid disease in both surveys (OR 1.60, 95%CI 0.87-2.95 for NHIS; OR 1.05, 95%CI 0.59-1.88 for NHANES).

CONCLUSION

A previously reported association between hypothyroidism and glaucomatous disease was not confirmed in two large U.S. health survey populations. While such an association was noted in the univariate analysis for the NHIS survey, such a relationship was not found in the multivariate analysis after adjustment for potential confounding variables.

The effect of orbital decompression surgery on refraction and intraocular pressure in patients with thyroid orbitopathy

PURPOSE

To investigate the effect of orbital decompression surgery in thyroid orbitopathy (TO) on both refractive status and intraocular pressure (IOP).

PATIENTS AND METHODS

A prospective, multicentre, consecutive audit of patients undergoing thyroid decompression surgery. Indications for surgery included cosmetically unacceptable proptosis or corneal exposure. Exclusion criteria included the following: previous orbital surgery, glaucoma, corneal disease, steroid use in the preceding 12 months, or an acute optic neuropathy. Automated refraction, keratometry, pachymetry, Hertel exophthalmometry, and IOP were recorded at 1 month pre- and 3 months postoperatively. IOP using the Tono-Pen (mean of three readings) was measured in the primary, upgaze, and downgaze positions.

RESULTS

Data were collected from 52 orbits of 33 patients (East Grinstead, New York, and Adelaide). There was no significant difference between pre- and postoperative data for sphere, cylinder, or central corneal thickness (CCT). The mean spherical equivalent was -0.43 ± 1.49 D pre-operatively and -0.28 ± 1.52 D postoperatively. The steepest meridian of corneal curvature was 93.1 degrees pre- and 94.2 degrees postoperatively, with no significant difference. Mean IOP significantly decreased when measuring by Goldmann applanation tonometry (GAT) (2.28 mm Hg, (*) P=0.001) and Tono-Pen (3.06 mm Hg, (*) P=<0.0001). IOP measured in upgaze was significantly greater than that in the primary position. Regression analysis between change in IOP and either Hertel exophthalmometry or the number of orbital walls decompressed was non-significant ((*)Student's t-test).

CONCLUSION

Patients with TO undergoing orbital decompression had, on average, with-the-rule astigmatism not affected by orbital decompression surgery. IOP was significantly reduced by decompression surgery although no relationship between IOP and the degree of decompression was observed.

Glaucoma and systemic diseases

Glaucoma management may be extremely challenging, especially in elderly patients who have a variety of systemic diseases and take multiple medications. We obtained a comprehensive medical history in patients with primary open-angle glaucoma to determine which systemic diseases are most prevalent and which systemic medications are most commonly used. We have also reviewed the literature that addresses how these concomitant diseases and medical treatments influence the management of glaucoma. Knowledge of systemic diseases and potential drug interactions, especially between various systemic and glaucoma medications, is important for the safe management of glaucoma patients.

A case of protruding eyeballs and diminishing vision

This case report discusses issues related to a 56-year-old man from Bangalore who presented with complaints of a gradual protrusion of his eyeballs along with diminishing vision for the previous month. The approach to diagnosis and management issues around this unusual presentation is dicussed.

Ocular changes in primary hypothyroidism

BACKGROUND

To determine the ocular changes related to hypothyrodism in newly diagnosed patients without orbitopathy.

FINDINGS

Thirty-three patients diagnosed to have primary overt hypothyroidism were enrolled in the study. All subjects were assigned to underwent central corneal thickness (CCT), anterior chamber volume, depth and angle measurements with the Scheimpflug camera (Pentacam, Oculus) and cup to disc ratio (C/D), mean retinal thickness and mean retinal nerve fiber layer (RNFL) thickness measurements with optical coherence tomography (OCT) in addition to ophthalmological examination preceeding the replacement therapy and at the 1(st), 3(rd )and 6(th )months of treatment. The mean age of the patients included in the study were 40.58 +/- 1.32 years. The thyroid hormone levels return to normal levels in all patients during the follow-up period, however the mean intraocular pressure (IOP) revealed no significant change. The mean CCT was 538.05 +/- 3.85 mu initially and demonstrated no statistically significant change as the anterior chamber volume, depth and angle measurements did. The mean C/D ratio was 0.29 +/- 0.03 and the mean retinal thickness was 255.83 +/- 19.49 mu initially and the treatment did not give rise to any significant change. The mean RNFL thickness was also stable during the control visits, so no statistically significant change was encountered.

CONCLUSIONS

Neither hypothyroidism, nor its replacement therapy gave rise to any change of IOP, CCT, anterior chamber parameters, RNFL, retinal thickness and C/D ratio.

The association between thyroid problems and glaucoma

AIMS

To evaluate the association between thyroid problems and glaucoma.

METHODS

A population-based cross-sectional sample with 12,376 participants from the 2002 National Health Interview Survey. Odds ratios (OR) and 95% confidence intervals (CIs) were used to quantify the association between a self-reported diagnosis of glaucoma and a self-reported history of thyroid problems, controlling for demographic characteristics and smoking status.

RESULTS

The overall prevalence of glaucoma was 4.6%; 11.9% reported a history of thyroid problems. The prevalence of glaucoma among those who did and did not report thyroid problems was 6.5% and 4.4%, respectively (p = 0.0003). Following adjustment for differences in age, gender, race and smoking status, the association between glaucoma and thyroid problems remained (OR 1.38, 95% CI 1.08 to 1.76).

CONCLUSIONS

The results of this study lend support to the hypothesis that thyroid disorders may increase the risk of glaucoma. Research should continue evaluating potential mechanisms underlying this relationship and whether the treatment of thyroid problems reduces subsequent glaucoma risk.

Is there an association between hypothyroidism and open-angle glaucoma in an elderly population? An epidemiologic study

PURPOSE

There have been conflicting reports pertaining to the association between hypothyroidism and open-angle glaucoma (OAG). The purpose of this study was to assess the hypothesized association between preexisting hypothyroidism and development of OAG in a population-based setting.

DESIGN

Case-control study.

PARTICIPANTS

The study population and controls were taken from all patients in a large US managed care database aged >or=60 years with 4 years of continuous eligibility dating from January 1, 2001, through December 31, 2004.

METHODS

A total of 4728 newly diagnosed OAG patients were matched with 14 184 controls (3:1 matching) based on age and gender.

MAIN OUTCOME MEASURES

Conditional logistic regression was used to assess the relationship between hypothyroidism and OAG while controlling for various risk factors (ischemic heart disease, cerebrovascular disease, hyperlipidemia, hypertension, arterial disease, diabetes, and migraines).

RESULTS

Based on a diagnosis of hypothyroidism or use of a thyroid replacement therapy, prior hypothyroidism was found in 815 (17.2%) OAG subjects and in 2498 (17.6%) control subjects. After adjusting for the specified risk factors, patients with OAG were not found to be associated with a prior hypothyroid diagnosis when compared with control subjects (odds ratio, 0.93; 95% confidence interval, 0.85-1.01).

CONCLUSIONS

An association between prior hypothyroidism and OAG development was not found. The large proportion of patients receiving thyroid replacement therapy may have negated any OAG-related consequences of hypothyroidism.

A Sick Eye in a Sick Body? Systemic Findings in Patients with Primary Open-angle Glaucoma

Despite intense research, the pathogenesis of primary open-angle glaucoma (POAG) is still not completely understood. There is ample evidence for a pathophysiological role of elevated intraocular pressure; however, several systemic factors may influence onset and progression of the disease. Systemic peculiarities found in POAG include alterations of the cardiovascular system, autonomic nervous system, immune system, as well as endocrinological, psychological, and sleep disturbances. An association between POAG and other neurodegenerative diseases, such as Alzheimer disease and Parkinson disease, has also been described. Furthermore, the diagnosis of glaucoma can affect the patient's quality of life. By highlighting the systemic alterations found in POAG, this review attempts to bring glaucoma into a broader medical context.

Central corneal thickness and normal tension glaucoma: A cross-sectional study

BACKGROUND

Recently published evidence has identified thinner central corneal thickness (CCT) as a strong predictive factor for the conversion from ocular hypertension (OHT) to primary open-angle glaucoma (POAG). The association between CCT and development of normal-tension glaucoma (NTG), however, is less clear. Accordingly, we designed this cross-sectional study to further explore the relationship between CCT and NTG.

PATIENTS AND METHODS

All patients with a clinical diagnosis of NTG and NTG suspect (NTGS) who were seen from September 2002 through May 2003 at the Albuquerque VA Medical Center eye clinic were identified retrospectively. After eligible subjects were categorized into no, mild, moderate, and advanced visual field loss groups, analysis of variance (ANOVA) and regression analyses were used to determine group differences for several IOP variables, several systemic variables, and CCT. Additional analyses were completed after eligible subjects were recategorized into thin, intermediate, and thick CCT groups.

RESULTS

Eighty-four eyes in 84 NTGS subjects and 56 eyes in 56 NTG subjects were studied. Mean CCT was significantly thicker in the no field loss group (NTGS) when compared with all 3 groups with glaucomatous visual field loss (NTG). In multivariate regression analysis, the association between CCT and the presence of NTG-related visual field loss was robust and independent. Conversely, no relationship was found between CCT and severity of NTG-related visual field loss.

CONCLUSIONS

In eyes characterized by statistically normal intraocular pressure (IOP) measurements as measured by Goldmann applanation tonometry, we found a significant relationship between CCT and the presence, but not severity, of glaucomatous visual field loss. A prospective study is required to further explore and confirm these relationships.

The relationship between central corneal thickness-adjusted intraocular pressure and glaucomatous visual-field loss

BACKGROUND

Although measurement of central corneal thickness (CCT) is increasingly becoming an important component of glaucoma risk analysis, significant controversy exists regarding the benefit of calculating a corrected intraocular pressure (IOP) value from measured IOP and CCT data.

METHODS

Three hundred forty-four male subjects were identified from a VA eye clinic with one of the following clinical diagnoses: ocular hypertension (OHT), primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and normal tension glaucoma suspect (NTGS). Using one eye per subject, multivariate logistic regression and correlational analyses were performed to determine relationships between glaucomatous visual-field loss and several glaucoma risk factors, including adjusted IOP values.

RESULTS

Multivariate logistic regression analysis did not identify CCT-adjusted IOP values as independent risk factors for development of either NTG or POAG-related glaucomatous visual-field loss. CCT, however, was found to be strongly associated with both NTG and POAG-related visual-field loss. Correlational analysis revealed a weak correlation between Ehlers-adjusted pre-treatment IOP and severity of POAG-related visual-field loss, but no other adjusted IOP values significantly correlated with severity of visual-field loss in either POAG or NTG.

CONCLUSIONS

Our results suggest that adjusted IOP, as calculated using current algorithms, is not useful within glaucoma risk analysis, since adjusted IOP was unable to predict either presence or severity of glaucomatous visual-field loss in this study. CCT, conversely, was found to be a robust and independent predictor of glaucomatous visual-field loss. These findings, while supporting routine CCT measurements for all glaucoma suspects, do not support routine clinical computation of adjusted IOP values using current algorithms.

Complications de l’ophtalmopathie dysthyroïdienne

The complications of dysthyroid ophthalmopathy should be known and screened in every patient since they can worsen visual prognosis and are critical to the decision for treatment. Ocular surface alteration can result from eyelid malposition, blinking deficiency, eye dryness, and proptosis. Oculomotor disorders are detected by coordimetry or a forced duction test. Optic neuropathy can be compressive or glaucomatous. Intraocular pressure elevation can result from elevation of intraorbital pressure, indentation by an enlarged muscle, or increased backflow in episcleral veins.

Hypothyroidism and the development of open-angle glaucoma in a male population

PURPOSE

To determine if hypothyroidism is associated with an increased risk of glaucoma using a large cohort of patients.

DESIGN

Nested case-control study.

PARTICIPANTS

Patients seen at the Veterans Affairs Medical Center in Birmingham, Alabama with newly diagnosed glaucoma between 1997 and 2001 were selected (n = 590) and age-matched to nonglaucoma controls (n = 5897).

METHODS

Patient information was extracted from the Birmingham Veterans Affairs Medical Center data files containing demographic, clinical, and medication information. An index date was assigned to the glaucoma subjects corresponding to the time of diagnosis. Patients who had a glaucoma diagnosis before the observation period of the study were excluded. Ten controls were randomly selected for each patient and matched on age (+/-1 year) and an encounter on or before the index date of the matched case.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for the association between the prior diagnosis of hypothyroidism and the risk of developing glaucoma with adjustment for the presence of diabetes, lipid metabolism disorders, hypertension, cardiovascular disease, cerebrovascular disease, arterial disease, and migraines.

RESULTS

After adjustment for the other potential risk factors, patients were significantly more likely to have prior hypothyroidism than controls (OR, 1.40; 95% confidence interval, 1.01-1.97).

CONCLUSIONS

Our study has demonstrated a significantly greater risk of subjects with a preexisting diagnosis of hypothyroidism developing glaucoma, compared with controls, in a large Veterans Affairs Medical Center population.

Open-angle glaucoma and systemic thyroid disease in an older population: The Blue Mountains Eye Study

PURPOSE

To assess whether thyroid disease is independently associated with open-angle glaucoma (OAG), using history of thyroid disease and current thyroxine use.

METHODS

The Blue Mountains Eye Study examined 3654 persons, aged 49-97 years. Interviewers collected self-reported history of diagnosis and treatment for thyroid disease. Eye examinations included applanation tonometry, stereoscopic optic disc photography and automated perimetry. OAG was diagnosed from the presence of matching typical glaucomatous field changes and optic disc cupping, independent of intraocular pressure. Associations between thyroid disease (history and treatment) and OAG were assessed in a multivariate model.

RESULTS

Of 324 participants (8.9%) reporting history of thyroid disease, 147 (4.0%) were currently using thyroxine. Although we could not accurately categorize the thyroid disorder for all cases, current use of thyroxine suggests a prior hypothyroid state. All thyroid disease subgroups affected women more frequently than men, P=0.001. OAG was diagnosed in 108 subjects (3.0%) and was more frequent in those reporting past thyroid disease (4.6 vs 2.8%). This relationship was not statistically significant after adjusting for potential confounders, multivariate odds ratio (OR) 1.6; 95% confidence interval (95% CI) 0.9-2.9. OAG was significantly more frequent, however, in subjects reporting current thyroxine use (6.8 vs 2.8%), multivariate OR 2.1; 95% CI 1.0-4.4, or history of thyroid surgery (6.5 vs 2.8%), multivariate OR 2.5; 95% CI 1.0-6.2.

CONCLUSIONS

This population-based study suggests that thyroid disease, indicated by current thyroxine use or past thyroid surgery, could be independently related to OAG.

Hypothyroidism and glaucoma. A study of 100 hypothyroid patients

PURPOSE

To determine whether glaucoma is associated with hypothyroidism, as has previously been suggested.

METHODS

This is a cross-sectional study and a noncomparative interventional case series. One hundred consecutive patients with newly diagnosed hypothyroidism were referred for complete ophthalmologic examination, including automated perimetry and examination of the optic disks, to identify the presence of glaucoma. After correction of the hypothyroidism, reexamination was performed.

RESULTS

No patient had glaucoma and no correlation was found between intraocular pressure and either thyroid stimulating hormone or free tri-iodothyronine. No statistically significant difference was found between intraocular pressure levels before and after treatment of the hypothyroidism.

CONCLUSION

This study does not demonstrate an association between hypothyroidism and glaucoma.

Primary open angle glaucoma and hypothyroidism: chance or true association?

The prevalence of hypothyroidism in British patients with primary open angle glaucoma (POAG) was examined. A recently reported study from Montreal had shown a significant increase (p < 0.004) in biochemical hypothyroidism (23.4%) in a population of 64 POAG patients compared with controls (4.7%). Mechanisms for a possible causal association between the two diseases are discussed, including mucopolysaccharide deposition in the trabecular meshwork and vasculopathy altering ocular bloodflow. Reports of improved glaucoma control following treatment of hypothyroidism are discussed. This study examined 100 consecutive patients with POAG in a specialist glaucoma clinic. All patients were questioned regarding symptoms of thyroid dysfunction and previous thyroid disease. All patients not already taking thyroxine underwent an assay of thyroid stimulating hormone. The 4% (95% CI 1.1-9.4%) prevalence of overt hypothyroidism in our study shows no clinically significant increase either over controls in the Montreal study or over our local population. We conclude that in our local population there is no evidence for a clinically important association of hypothyroidism with glaucoma.