This is in response to one of my blog entries and the question which was asked which was "Which stage do you prefer to do a Gundersen flap?"
How severe, deep or advanced is the corneal ulcer with the initial presentation often helps to determine your decision. There are often other factors that might influence your actions ---- what has the patient been using in the eye ( steroids / traditional medicines ? ), does the patient have other health concerns / issues, is there any improvement in the ulcer / abscess, is the fluorescein - staining epithelial defect decreasing in size, etc. If the patient has already been using several different antibiotics, then I assume the ulcer is fungal or a combination. Cultures are often not possible to obtain. Often you will not get a history of previous minor eye trauma unlike southern Florida.
Improvement can mean a reduction in pain ( which may be the first indication you are winning ), a slightly better vision, a decrease in injection / limbitis , a decrease ( clearing ) of the stromal infiltrate / opacity, a reduction in the hypopyon, or especially a decrease in the size / shape of the fluorescein - staining epithelial defect. I have mentioned previously that my " full-court press" includes povidone-iodine 5%, Natamycin 5% ( shake ), anti-fungal skin or vaginal cream, chloramphenicol or Polytrim or fluoroquinolone drops, oral ketoconazole or itraconazole with Coke, oral doxycycline with food, and cyclopentolate. I would not use steroids nor NSAIDS drops. These corneal ulcers can often take weeks ( months ) to heal and will obviously result in a permanent loss of vision. What you would like not to see is a chronic large deep non-healing indolent corneal ulcer with the epithelial defect not healing / closing / changing. Thinning of the corneal bed is not good.
You want to do the Gundersen conjunctival flap before any perforation. Ideally before a descemetocele develops but often these patients present initially with a descemetocele. If you have no improvement in the corneal situation in two or three weeks then I would proceed with the Gundersen flap. Maybe sooner. I certainly have waited too long and then the patient perforates. Usually the eye is then finished as there is no possibility of a therapeutic keratoplasty. You can try using glue but often an evisceration is needed. If the ulcer bed is quite deep and you are worried about a pending perforation then it's probably time for the O.R. if you have seen no improvement. You can save many eyes in the developing world with Gundersen flaps. Earlier is often better.
Last week I did an evisceration on a patient with a large old corneal abscess who had perforated. Other than the corneal abscess the eye was intact. Not the best scenario.
Thanks again for the question. Corneal problems are certainly more common in the developing world than the industrialized world.