Introduction
An eating disorder is a psychiatric condition where one controls food to manage their feelings. It includes anorexia nervosa, bulimia nervosa, and binge eating disorders. The disorder is characterized by eating less or more and worrying about weight. It can affect anyone. However, teenagers are more prone. Women are more prone to it as compared to men. Eating disorders affect many systems at once, including the eyes. Eye problems due to eating disorders include visual loss, both acute and chronic, dry eyes, lagophthalmos, nystagmus, and ophthalmoplegia.
What Are the Different Types of Eating Disorders?
Anorexia Nervosa - It is characterized by a fear of weight gain and an abnormally low weight.
Bulimia Nervosa - It is an eating disorder that is characterized by overeating and then trying to lose weight by purging or fasting.
Binge Eating Disorder - It is an eating disorder where the individual eats frequently and uncontrollably.
What Are the Common Eye Problems That Arise as a Result of Eating Disorders?
The different eye problems resulting from certain eating disorders are as follows:
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Lagophthalmos - Lagophthalmos is the incomplete closure of the eyelids. A complete eyelid closure and normal blinking are essential for maintaining a healthy eye. Individuals with incomplete eyelid closure and improper blinking are at an increased risk of dry eyes due to continuous tear film evaporation and keratopathy. This can lead to ulceration and perforation of the cornea. The most important cause of the condition is facial nerve paralysis. People with eating disorders commonly have orbital fat atrophy. In this condition, the fat cells around the eyes start to shrink. This reduction in the orbital fat can cause lagophthalmos. It is specifically seen in individuals with anorexia nervosa.
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Acute Loss of Vision - Eating disorders could also lead to acute vision loss. It includes a reduction in the thickness of the retinal nerve fiber layer (formed by the retinal ganglion cells that collect the visual signals), fluffy white retinal patches (cotton wool spots), and dense intraretinal hemorrhages of the optic disc.
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Deficiency of Thiamin - Vitamin B1 deficiency or Wernicke encephalopathy is an acute neurological condition that comprises ophthalmoparesis with nystagmus, ataxia, and confusion. It affects the central and peripheral nervous systems.
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Idiopathic Intracranial Hypertension - Pseudotumor cerebri, also known as idiopathic intracranial hypertension, can occur after excess weight gain. Increased weight due to bulimia nervosa and binge eating disorder makes one prone to increased intracranial hypertension. Refeeding syndrome after anorexia nervosa is characterized by a period of feeding post-malnutrition. It leads to hypophosphatemia associated with clinical and metabolic complications due to a shift in fluids and electrolytes. If refeeding syndrome is not monitored mindfully, it may cause a drift of the nutrients out of circulation, leading to eye problems and other conditions.
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Other eye conditions related to eating disorders are bilateral symmetric central vision loss and optic atrophy.
How to Diagnose Eye Problems Due to Eating Disorders?
A Thorough History:
The diagnosis is based on the history and symptoms of the eating disorder present in the person. In anorexia nervosa, the person aims to maintain a low body weight and body mass index. Eye problems like lagophthalmos, dry eyes, or decreased vision often exist with anorexia nervosa. If the eating disorder causes a thiamin or B1 deficiency, the individual can get ataxia, nystagmus, confusion, and ophthalmoplegia. A person with bulimia nervosa tends to force vomiting and excessive use of laxatives. Forced vomiting creates increased
pressure, which may cause a subconjunctival hemorrhage. These hemorrhages are usually painless and asymptomatic. People with binge eating disorders may develop idiopathic intracranial hypertension due to excessive weight gain, which could cause headaches and cranial nerve palsies.
Physical Examination:
The patient's physical examination depends on the type of eating disorder they have. The eye examination of such individuals may show lagophthalmos along with narrowing of the palpebral fissures and dry eyes. Depending on the extent of the disorder, there could also be decreased vision. The physical examination of a person with bulimia nervosa may show subconjunctival hemorrhages. Binge eating disorder individuals have papilledema and increased intracranial pressure. On examination, the deficiency of B9 or B12 shows bilateral vision loss in both eyes and optic atrophy.
Diagnostic Modalities:
Eye problems can be diagnosed with the help of optical coherence tomography and fundoscopy. It helps diagnose reduced RNFL thickness, retinopathy signs like cotton wool spots, and intraretinal hemorrhages. For bulimia nervosa, there is no specific diagnostic procedure, as the symptoms can be seen with the naked eye. A brain MRI and MRV (magnetic resonance venography) can detect signs of intracranial hypertension for binge eating disorders. Both modalities can help differentiate other conditions leading to increased intracranial pressure, like stroke. A lumbar puncture can also detect the symptoms present due to increased intracranial pressure.
Laboratory Diagnostic Procedures:
There are very few laboratory tests that help identify the condition. The following are the tests:
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Vitamin B1 Level - These can be calculated by measuring the transketolase activity.
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Arterial Blood Gas Test - An increased serum bicarbonate level can be seen in anorexia nervosa individuals. Metabolic acidosis is seen in patients with overuse of laxatives.
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Complete Blood Count - This checks for anemia, lipid profile, electrolyte abnormalities, and liver enzymes.
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Urinalysis - Complete urine test to check for abnormalities.
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Serum homocysteine levels.
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Methylmalonic acid levels.
How to Treat the Eye Problems Due to Eating Disorders?
Eating disorders can be managed with medicines and behavioral and nutritional therapy. The various eye disorders arising from these nutritional disorders can be managed surgically and medicinally. Lagophthalmos can be treated surgically by sewing the eyelids together to reduce excessive eyelid opening. Inserting gold and platinum weights into the upper eyelids eventually helps pull the eyelids down. Idiopathic intracranial hypertension following a binge eating disorder can be treated with Acetazolamide therapy. Other therapies include optic nerve sheath fenestration or cerebrospinal fluid diversion.
Conclusion
The eyes require proper nutrition to function. Individuals with eating disorders like anorexia nervosa do not eat a balanced meal to nourish themselves. Malnutrition causes disorders of the eyes and vision. Thus, treating the eating disorder is essential for eye health. It is essential to get the eyes checked on a regular basis and undergo treatment as advised by the doctor to avoid a loss of vision.
