Herpes Zoster Ophthalmicus

Herpes zoster ophthalmicus  HZO, also known as Ocular Shingles, is a painful dermatomal rash around the eye region and forehead caused by the reactivation of the Varicella Zoster Virus (VZV). It affects the trigeminal nerve of the ophthalmic division and eventually spreads to the other structures of the eye. The first division of the trigeminal nerve is the most common site for the development of acute herpes zoster.

Varicella-zoster virus manifests at two different stages in humans. At primary level the virus causes chicken pox after which it remains dormant for several years and reappears as herpes zoster later in the patient’s life. Aging, poor nutrition and low immunity are some of the risk factors that leads to the outbreak of Herpes zoster ophthalmic us (HZO).

Symptoms

HZO begins with flu-like symptoms including fever, Myalgia, and malaise for nearly a week. Typically, patients then develop tingling sensation and painful rash on the forehead and ocular symptoms such as eyelid edema; conjunctival, episcleral and circumcorneal conjunctival hyperemia; corneal edema and light sensitivity. All these symptoms are unilateral - occurring on one side of the face. 

Diagnosis

Herpes zoster ophthalmicus (HZO) is diagnosed clinically by mere observation of the symptoms. During a clinical visit, the ophthalmologist conducts a detailed examination of  visual acuity, visual fields, extra ocular movements, pupillary response, corneal function, Intraocular Pressure and anterior chamber. Doctor also makes a note of past history of chicken pox infection along with clinical examination. Viral culture, direct immunofluorescence assay, or Polymerase chain reaction (PCR) may also be used to confirm the diagnosis. Any signs of Hutchinson disease strongly indicates ocular complications such as inflammation and corneal denervation and forms the basis for diagnosis of herpes zoster ophthalmicus.

Treatment

Herpes zoster ophthalmicus is a medical emergency and should be treated promptly to avoid vision loss. The disease leads to many ocular conditions such as dermatitis, corneal pseudo-dendrites, uveitis, retinitis, and in rare cases it also causes cranial nerve palsies. Oral anti viral medicines like Acyclovir and Famcyclovir play a major role in treating herpes zoster ophthalmicus. Atropine eye drops are also prescribed to alleviate the painful symptoms. In case keratitis develops, Corticosteroid drops along with Cycloplegics (eye drops to induce ciliary muscle paralysis) may also be considered.

Glaucoma

Glaucoma is a disease of the eye where the patient develops blind spots in the visual field. This usually starts with the peripheral vision. Glaucoma is a leading cause for blindness worldwide. Early detection is vital in treating glaucoma. Glaucoma is noticed more among Asians and African-Americans. It usually affects persons who are above 60 years. Glaucoma tends to be hereditary. An injury to the eye can result in glaucoma in later years. Other factors such as hypertension, diabetes or high myopia increase the risk of glaucoma.

Intra ocular pressure(IOP) is a primary cause for glaucoma. Primary open-angle glaucoma usually does not exhibit any symptoms and continues to damage the optic nerve. Acute angle-closure glaucoma is a condition where the disease develops rapidly subsequent to rapid rise in eye pressure. Here the patient may suffer severe eye pain and blurred vision. This might be accompanied by nausea and vomiting. Here the drainage angle between the cornea and iris gets blocked. This can happen due to normal aging process or farsightedness. Secondary glaucoma is a condition where the glaucoma develops due to increased eye pressure caused by some other disease.

Tonometry is a test for intraocular pressure. The ophthalmologist will check for damage to optic nerve and check how much of your visual field has been affected. These tests aid in detecting the amount of damage caused by glaucoma and progression of the disease.

Glaucoma can only be controlled, not cured. Eye drops, oral medications and surgical procedures can slow down the damage caused by the disease. Glaucoma Medications include beta blockers, prostaglandin analogs, cholinesterase inhibitor and adrenergic. Oral medications may also be prescribed to reduce eye pressure. But these medications may bring about side effects. Laser surgery or trabeculoplasty is often used to tackle open-angle glaucoma. This surgical procedure aims to drain the aqueous humor from the eye and reduce pressure. It does not require hospitalization.

Pediatric Ophthalmologist

Pediatric ophthalmology is a sub specialty of ophthalmology concerned with vision care and eye diseases in children. A pediatric ophthalmologist provides comprehensive care in diagnostic, treatment and management of infant vision and common childhood vision disorders. Surgery to correct ocular misalignment and double vision in children are also performed by a pediatric ophthalmologist. Pediatric ophthalmologists are physicians who have completed a three year residency in ophthalmology after the medical school and one year internship and one or two year fellowship in pediatric ophthalmology and strabismus. Pediatric ophthalmology fellowships are accredited by the American Association for Pediatric Ophthalmology and Strabismus in the US.

Role of a pediatric ophthalmologist in child vision care:

• It could be opined that in young infants and children the visual system is not fully mature. As such, equal input from both eyes is required for proper development of visual centers in the brain in a human being. There could be the danger of permanent irreversible loss if the child's growing eye does not provide clear and focused image to the developing brain. A pediatric ophthalmologist provides early detection and effective treatment under such circumstances.
  
• Children suffer from reduced vision in one or both eyes from Amblyopia, uncorrected refractive errors and misalignment of the eyes called strabismus. It is the domain of the pediatric ophthalmologist to detect such innate errors in children and provide effective and efficient treatment. Among the vision problems that the pediatric ophthalmologist evaluates for the child include:
  
• Amblyopia: This is caused in an infant whose brain does not recognize the sight from the eye. In other words, there is poor vision in the eye appearing normal.
  
• Strabismus: This is misalignment of the eyes in any direction. About 4% of the children are affected by this disorder.
  
• Refractive errors: Such errors can cause decreased vision resulting in visual discomfort, eye strain and also Amblyopia.
  
• Genetic disorders: Approximately about 8% of genetic syndromes affect the eyes of children. Examination by a pediatric ophthalmologist helps to diagnose such genetic conditions. Sometimes certain eye conditions such as high internal pressure 'intraocular pressure' which can lead to glaucoma can be inherited in family members even when they are young. It is imperative on the part of the parent to inform the pediatric ophthalmologist about such conditions. Many pediatric ophthalmologists participate with multi disciplinary medical teams that treat children with genetic syndromes.

Tests conducted by pediatric ophthalmologist

• Penlight Eye Inspection: A small penlight is aimed into the child's eye, beginning with the newborn infants. The pediatric ophthalmologist checks and makes sure that the eye structures and eyelids appear normal and also if the eyes react appropriately to the presence of light. The pediatric ophthalmologist also checks for any early signs that eyes might be misaligned.
  
• Red Reflex test: The internal eye structure in particular, the red reflection from the inner back of the eye where the light sensitive retina is located is examined for the presence of any eye disease. This is done using an ophthalmoscope.
  
• Snellen Eye chart: This eye check contains letters and numbers which are used to test the sharpness of vision. This test can be done on children above the age of three years depending upon their comprehension. Sometimes certain cards with pictures are used to test for visual acuity testing.