Body Mass Index and Eye Pressure: Unveiling the Hidden Connection

Nistha Thapa, B.Sc. Optometry

Student, Acharya Institute of Allied Health Sciences, Bengaluru, India

 

Intraocular pressure (IOP) is an important element in the development and progression of glaucoma, the leading cause of irreversible blindness globally. Elevated IOP is the primary modifiable risk factor for glaucoma, however the effect of systemic variables such as Body Mass Index (BMI) on IOP is still under investigation. This blog investigates the link between BMI and IOP, using findings from recent studies.

Understanding the Link Between BMI and IOP:

Glaucoma and IOP:

Damage to the optic nerve resulting in loss of vision field characterises glaucoma, a neurodegenerative disease. The risk of glaucomatous optic nerve injury is significantly increased by elevated IOP. If IOP is higher than 23.75 mmHg, there is a noticeable increase in the chance of getting glaucoma; at pressures higher than 25.75 mmHg, there is a rapid jump in risk. Early glaucoma detection and prevention depend on the identification of variables that affect intraocular pressure (IOP).⁽¹⁾

BMI’s Influence on IOP:

According to research, BMI correlates favourably with IOP. Research on a Pakistani population discovered a direct correlation between greater BMI and increased IOP. The research, which included 300 subjects, found that an increase in BMI corresponded to an increase in IOP. A 1 kg/m² increase in BMI was linked to a 0.23 mmHg rise in IOP for men and a 0.14 mmHg increase for women. This positive connection was statistically significant, consistent with international studies indicating that obesity might cause elevated IOP.⁽¹⁾

On the other hand, Brazilian research on children found no significant relationship between BMI and IOP. There was no difference in IOP between children who were overweight or obese and those who were not, despite the high prevalence of obesity in the research. This disparity might be the result of variations in BMI cut-off points and assessment techniques, for example, Goldmann tonometry’s propensity to misrepresent IOP in people with elevated BMI.⁽²⁾

The Pathophysiological Mechanisms:

Numerous elements are involved in the underlying processes that relate BMI and IOP. Obese people with excess intraorbital fat may have increased IOP because of decreased aqueous humour outflow and increased episcleral venous pressure.⁽¹⁾ Moreover, hypertension and elevated blood viscosity—both of which can lead to elevated IOP—are linked to obesity.

Variability in Findings:

The necessity for localised research is shown by the variations in findings across different studies. Even though research from throughout the world frequently shows a favourable correlation between BMI and IOP, findings may vary according to the community or age group studied. For example, evidence from Turkey and Japan lends credence to the idea that obesity raises IOP, but studies in youngsters have produced contradictory findings.^(1,2) Variations in methodology and elements unique to a certain community may be the cause of the discrepancies.

Conclusion:

In conclusion, there is widespread agreement that a higher BMI is related with greater IOP, which may increase the risk of glaucoma. However, the association does not hold true across all populations and age ranges. More study is needed to clarify these correlations and better understand the function of BMI in IOP modulation, especially in varied demographic situations. Addressing these information gaps is critical for creating effective glaucoma preventive and care techniques.⁽³⁾

 

References:

1. Zainab H, Iqbal Z, Naz MA, Awan AH, Ishaq M. RELATIONSHIP BETWEEN INTRAOCULAR PRESSURE AND BODY MASS INDEX: Intraocular Pressure and Body Mass Index. Pakistan Armed Forces Medical Journal. 2014 May 5;64(3):391-94.
2. Albuquerque LL, Gaete MI, Figueiroa JN, Alves JG. The correlation between body mass index and intraocular pressure in children. Arquivos brasileiros de oftalmologia. 2013;76:10-2.
3. Mufti M, Nasti H, Shora T. Relationship between intraocular pressure and body mass index. National Journal of Physiology, Pharmacy and Pharmacology. 2019 Feb 6;9(6):540-.