Herpetic Retinitis

Herpes keratitis is a viral infection of the eye caused by the herpes simplex virus; type 1 is the most common. Infection can be transferred to the eye by touching an active lesion and then your eye.

Epidemiology

Herpetic eye disease is the most prevalent infectious cause of corneal blindness in developed countries. Seroprevalence of HSV-1 is over 50% in the US and 75% in Germany. About 90% of the population is exposed to HSV-1,

Corneal epithelial cells express specific receptors (Nectin 1, HVEM and PILR-alpha) that let viral entry into the cells. The primary infection is commonly subclinical, and the only manifestation may be self-limiting blepharoconjunctivitis without corneal involvement. During this phase the virus is carried to the trigeminal ganglion (V1 branch) and becomes latent. Recurrent infection occurs when this latent virus becomes reactivated (due to fever, trauma or immunosuppression), the episodes may be limited to the epithelium with epithelial cell involvement (dendritic/geographical keratitis) or it may go on to involve the deeper endothelial layer (disciform/stromal

• Pain, redness, rash, blurred vision, tearing, discharge, sensitivity to light.
• If the infection is superficial, involving only the cornea outer layer (epithelium) it will usually heal without scarring.
• On the other hand, if involves the deeper layers of cornea (can happen after time), the infection may lead to scarring of the cornea, loss of vision and sometimes even blindness.

-Medical history à previous attacks of herpes ocular infections

-External examinationà distribution of skin vesicles concentrated around the eye.

-Slit lamp examination à finding a dendrite is enough to confirm diagnosis in most cases, when is not very clear a viral culture of the lesion can confirm the diagnosis. HSV antibody titers rise after primary but not recurrent infection.

-Characteristic findings include a branching dendritic or serpentine corneal lesion (indicating dendritic keratitis), disc shaped, localized corneal edema and haze plus anterior uveitis (indicating disciform keratitis) or stromal scarring (indicating stromal keratitis).

-Epithelial keratitisà we use topical Acyclovir and ganciclovir gel, each administered five times daily. Also, we can use Trifluridine up to nine times a day; 99% of cases resolve by two weeks on this treatment.

-Debridement à  This technique can be employed for dendritic but not geographical ulcers.

-Oral antivirals à for patients who respond poorly to topical therapy benefit from this method.

-Interferon monotherapy à a combination of nucleoside antiviral with interferon speeds up healing.

-IOP control à  prostaglandin derivatives should be avoided as they promote viral activity and inflammation in general.

Since there is no complete cure for herpes, but if you develop herpes keratitis, there are some things you can do to help prevent recurring outbreaks:

– If you have an active cold sore or blister, avoid touching your eyes and stop wearing contact lenses.

– You should not use steroid eye drops unless you are taking an anti-viral medicine as well, because can increase HSV in the body.