Obesity is a serious public health problem worldwide, a veritable silent pandemic that has innumerable correlations with numerous eye diseases, as it is a systemic condition that affects the health of the entire organism with significant repercussions on the visual apparatus.
The latest official WHO data are for 2022 and report a worldwide figure of 43% of adults over the age of 18 who are overweight and 16% who are obese, a total of 890 million people.
Globally, an estimated 28 million people die each year from overweight or obesity-related illnesses or experience severe disabilities that lead to a significant deterioration in their quality of life.
These include:
- Cardiovascular diseases, mainly heart attack and stroke
- Type 2 diabetes mellitus
- Musculoskeletal disorders, particularly osteoarthritis
- Certain types of cancer, including endometrial, breast, ovarian, prostate, liver and bladder, kidney and colon cancers.
- Eye diseases
Eye diseases that have been found to be associated with obesity based on studies available in the literature include:
- Cataracts, especially in posterior cortical and subcapsular forms
- Glaucomatous optic neuropathy
- Age-Related Macular Degeneration
- Occlusion of retinal veins and arteries
- Dry eye syndrome
- Papilledema
- Uveitis
They were found to be specifically related to obstructive sleep apnoea, a condition very common in the obese:
- Flag iris syndrome
- Central serous chorioretinitis
- Normal-tension glaucoma
- Non-arteritic anterior ischaemic optic neuropathy
The etiopathogenetic mechanisms that explain the role of obesity in the onset of eye diseases include primarily inflammation, oxidative stress, hormonal and metabolic imbalances.
Until now, obesity has been diagnosed on the basis of Body Mass Index, (BMI), which has proven to be an inaccurate parameter, as it can lead to over- and under-diagnosis. A commission of 56 experts has now developed a set of 18 criteria, Lancet Diabetes & Endocrinology Commission on the Definition and Diagnosis of Clinical Obesity - The Lancet Diabetes & Endocrinologyincluding waist circumference or direct measurement of fat by Dexa (bone densitometry scan) - and distinguished between two types of obesity, clinical and pre-clinical. Clinical obesity indicates a true chronic disease associated with concomitant organ dysfunction, while pre-clinical obesity is associated with a variable degree of health risk, but without concomitant disease.
The Commission has therefore set 18 diagnostic criteria for clinical obesity in adults and 13 specific criteria for children and adolescents, including: dyspnoea (breathlessness), heart failure, knee or hip pain, certain bone and joint alterations in children and adolescents that can restrict movement, other signs and symptoms caused by dysfunction in other organs (including the kidneys, respiratory tract, nervous system, urinary system, reproductive system).
For eye diseases, a systematic population-based review, Obesity and risk of age-related eye diseases: a systematic review of prospective population-based studiesanalysed the correlation between anthropometric data and four specific eye diseases, cataract, glaucoma, AMD and diabetic retinopathy. It is worth noting the significant differences between the various populations examined. For example, obesity defined by BMI is positively associated with AMD in Western populations, but not in Asian populations, and the same is true for diabetic retinopathy. This apparent paradox can be explained by the fact that some people tend to accumulate excess fat at waist level, while others in or around their organs, such as liver, heart or muscles. The latter morphological arrangement is associated with a greater health risk than when excess fat is located only under the skin, in the arms, legs or other areas. In general, waist circumference was found to be a more reliable parameter than body mass index for non-Western populations. Further longitudinal studies are, however, needed, particularly on abdominal fat deposits and the effects of weight loss to better understand the aetiology and to be able to prevent overweight-related eye diseases.
- Bosello F, Vanzo A, Zaffalon C, et al. Obesity, body fat distribution and eye diseases. Eat Weight Disord. 2024 May 6;29(1):33. doi: 10.1007/s40519-024-01662-8. PMID: 38710948; PMCID: PMC11074037.
- Kapoor N, Jasper S, Kalra S. Ocular manifestations of obesity: beyond what meets the eye. J Pak Med Assoc. 2022;72:574. doi: 10.47391/JPMA.22-020.
- Ng Yin Ling C, Lim SC, Jonas JB, Sabanayagam C. Obesity and risk of age-related eye diseases: a systematic review of prospective population-based studies. Int J Obes. 2021;45:1863-1885. doi: 10.1038/s41366-021-00829-y.
- Lancet Diabetes & EndocrinologyCommission on the Definition and Diagnosis of Clinical Obesity Rubino, Francesco et al. The Lancet Diabetes & Endocrinology, Volume 11, Issue 4, 226 - 228