Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Home Print this page Email this page
Users Online: 113



 Table of Contents  
COMMENTARY
Year : 2014  |  Volume : 11  |  Issue : 1  |  Page : 4-5

Hypothyroidism and glaucoma: Is there an association?


Vasan Eye Clinic, Kothrud, Pune, Maharashtra, India

Date of Web Publication2-Jan-2014

Correspondence Address:
Savita Bhat
Vasan Eye Clinic, Kothrud, Pune, Maharashtra
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


Rights and PermissionsRights and Permissions

How to cite this article:
Bhat S. Hypothyroidism and glaucoma: Is there an association?. Thyroid Res Pract 2014;11:4-5

How to cite this URL:
Bhat S. Hypothyroidism and glaucoma: Is there an association?. Thyroid Res Pract [serial online] 2014 [cited 2019 Jun 15];11:4-5. Available from: http://www.thetrp.net/text.asp?2014/11/1/4/124185

Glaucoma is an important cause of blindness world-wide, as a rise in intraocular pressure is associated with optic disc damage. Recently, a large study had indicated an association between hypothyroidism and glaucoma. [1] Hypothyroidism is also a common disease. [2] This article aims to put the issue of hypothyroidism and its link to glaucoma in perspective for the clinician treating this illness.

In a large cross-sectional study of over 12,376 subjects in the USA, authors reported an association between the hypothyroidism and glaucoma. [1] This was a population based study, as part of the large National Health Interview Survey. The authors report that about 4.6% of subjects reported glaucoma, while 11.9% of subjects reported a thyroid disorder. Among patients with who reported thyroid disease, 6.5% also reported glaucoma. And, among patients who did not report thyroid disease, only 4.4% reported glaucoma. This difference was statistically significant and remained so despite adjusting for various confounding factors, like for instance, age as well as gender and smoking with an odds ratio of 1.38 in the study. Although the results do not directly implicate hypothyroidism, as hypothyroidism is arguably among the most common of thyroid problems, this association reported by Cross et al., deserves critical study. [1]

Why is there an association between hypothyroidism and glaucoma? Well, it has been postulated by Smith et al., as early as in 1993, that hypothyroidism causes the deposition of hyaluronic acid and related materiel in the trabecular mesh work of the eye, this raising intraocular pressures. [3] The same group also reported that the prevalence of open angle glaucoma in subjects with hypothyroidism was high as high as 23%. However, this association has been questioned in other studies. Interestingly, Centanni et al., reported that the intra-ocular pressures (IOP) may be elevated even in patients with subclinical hypothyroidism. [4] The authors also report that the use of levothyroxine reduced the raised IOP seen in subjects with subclinical hypothyroidism. [4]

Although the data has been conflicting, the question that clinicians would be most interested in knowing would be this given the association between hypothyroidism in glaucoma, should doctors actively screen for hypothyroidism in subjects with glaucoma. Well, this clinical question was recently addressed in a study published from Greece. [5] The authors selected 78 subjects with primary open angle glaucoma and also took a carefully selected control group. Thyroid function tests were carried out in both groups and the authors report no statistically significant differences in thyroid function parameters or the prevalence of hypothyroidism. This led the authors to suggest that there seems to be no rationale for actively screening patients with glaucoma for hypothyroidism.

What about the role of screening for glaucoma in subjects with hypothyroidism? While the previous studies have reported a high prevalence, as discussed earlier larger study or a meta-analysis would yield significant clues. For the present, clinicians should screen for glaucoma in hypothyroid subjects only in the presence of additional, well-known risk factors for glaucoma. The association between thyroid-associated orbitopathy and glaucoma is well-known, with several plausible biological mechanisms to explain the link. [6] For example, in Graves' disease with thyroid associated orbitopathy, the pressure of the enlarged extra-ocular muscles against orbital adhesions might increase IOP. In addition, it is well-known that giving the finite volume of the orbit, any increase in the volume of orbital contents might cause orbital congestion and this orbital congestion might also increase the episcleral venous pressures leading to glaucoma. To support this theory, there is an evidence to suggest that the activity of orbitopathy i.e., the duration of active thyroid-associated orbitopathy is a marker of glaucomatous damage to the disc. [7] Thus, treatment to reduce the activity of thyroid associated orbitopathy might help in preventing glaucomatous damage and people with long-duration thyroid associated orbitopathy may require special monitoring. Interestingly, hypothyroidism has been associated rarely with thyroid associated orbitopathy, which is classically associated with Graves' hyperthyroidism. [8]

However, the impact of this hypothyroidism on IOP in the setting of orbitopathy has not been clearly established. The issue of hypothyroidism and glaucoma therefore is more complex than it may seem. Does thyroid hormone therapy in patients with hypothyroidism result in a change of IOP in those without glaucoma? This issue was explored in a recent study that evaluated the effect of levothyroxine therapy on several ocular parameters IOP, central corneal thickness, anterior chamber parameters, retinal nerve fiber layer thickness, retinal thickness and cup to disc ratio. [9] Thirty three patients were studied with overt hypothyroidism and levothyroxine therapy normalized thyroid hormone levels in all patients; however, there was no change in any of the ocular parameters including intraocular pressures in these patients with thyroid hormone replacement. This carefully carried out study questions the association between high IOPs in hypothyroidism and their resolution with levothyroxine. Clearly, the association between hypothyroidism and glaucoma has not been established and remains an interesting, hypothetical link that deserves further study.

 
  References Top

1.Cross JM, Girkin CA, Owsley C, McGwin G Jr. The association between thyroid problems and glaucoma. Br J Ophthalmol 2008;92:1503-5.  Back to cited text no. 1
[PUBMED]    
2.Unnikrishnan AG, Kalra S, Sahay RK, Bantwal G, John M, Tewari N. Prevalence of hypothyroidism in adults: An epidemiological study in eight cities of India. Indian J Endocrinol Metab 2013;17:647-52.  Back to cited text no. 2
[PUBMED]    
3.Smith KD, Arthurs BP, Saheb N. An association between hypothyroidism and primary open-angle glaucoma. Ophthalmology 1993;100:1580-4.  Back to cited text no. 3
[PUBMED]    
4.Centanni M, Cesareo R, Verallo O, Brinelli M, Canettieri G, Viceconti N, et al. Reversible increase of intraocular pressure in subclinical hypothyroid patients. Eur J Endocrinol 1997;136:595-8.  Back to cited text no. 4
[PUBMED]    
5.Kitsos G, Pappa C, Tsatsoulis A. Primary open angle glaucoma and hypothyroidism. J Clin Optom 2010;2:5-8.  Back to cited text no. 5
    
6.Bhat S, Unnikrishnan AG, Jeyapathy P, Kumar H, Jayakumar RV. Glaucoma and thyroid disease-An interesting association. Thyroid Res Pract 2010;7:35-6.  Back to cited text no. 6
  Medknow Journal  
7.Cockerham KP, Pal C, Jani B, Wolter A, Kennerdell JS. The prevalence and implications of ocular hypertension and glaucoma in thyroid-associated orbitopathy. Ophthalmology 1997;104:914-7.  Back to cited text no. 7
[PUBMED]    
8.Putta-Manohar S, Perros P. Epidemiology of Graves' orbitopathy. Pediatr Endocrinol Rev 2010;7 Suppl 2:182-5.  Back to cited text no. 8
[PUBMED]    
9.Ozturk BT, Kerimoglu H, Dikbas O, Pekel H, Gonen MS. Ocular changes in primary hypothyroidism. BMC Res Notes 2009;2:266.  Back to cited text no. 9
[PUBMED]    




 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
References

 Article Access Statistics
    Viewed8555    
    Printed95    
    Emailed0    
    PDF Downloaded381    
    Comments [Add]    

Recommend this journal