The approach to managing patients with ocular herpes employed in Europe, the USA and several Asian countries boils down to the following combination: chemotherapy agent + corticosteroid.
In 1962, H.E. Kaufman introduced the first chemotherapy agent aimed at ocular herpes, IDU. In 1978, Acyclovir (also known as Zovirax) was developed. IDU has almost no place in modern ophthalmology, with the most popular chemotherapy drugs being Acyclovir, Cidofovir and Foscarnet.
The mechanism of action of these agents is associated with inhibition of viral replication inside cells to a greater (Acyclovir) or lesser (other drugs) extent.
However, their toxicity is so high that it often mitigates the therapeutic effect. Among the disadvantages of chemotherapy agents are:
To be fair, Acyclovir has several advantages over other chemotherapy agents and is an effective antiviral drug. It is an irreplaceable “antiviral shield” for patients after corneal grafting for ocular herpes.
The combination of Acyclovir and Poludan is the gold standard for ocular herpes. According to A.A. Kasparov (1991), combined use of these two drugs with different mechanisms of action provided a synergistic effect which translated into shorter treatment courses and increased recovery rates.
It is now well known that steroids promote herpes infection in the cornea and are thus unacceptable as monotherapy without antiviral agents.
It is these steroid-complicated forms of herpes simplex keratitis that are the leading causes of blindness and disability as a result of rapid development of severe leucoma and corneal perforation with subsequent complicated cataract, secondary glaucoma and endophthalmitis.
The latter two complications along with acute retinal necrosis are frequent causes of irreversible blindness associated with ocular herpes.
Summing up, the first component (chemotherapy drugs) leads to severe toxic reactions and gives rise to resistant viral strains, while the second (steroids) compromises the immune system, activates the virus, hampers regeneration and promotes secondary bacterial infection resulting in severe complications and even blindness.