PESARO, Italy – Although endophthalmitis remains a potential cause of visual loss, both medical therapies and surgical techniques have evolved so that the prognosis is not always as negative as it used to be.
New developments in the treatment of endophthalmitis were discussed at the summer session of the “Italiani d’America” meeting organized by Cesare Forlini, MD, where guests of honor were a group of American ophthalmologists of Italian descent.
The main issue of this session was post-cataract, acute endophthalmitis.
Painless hypopyon is the usual presentation of post-cataract endophthalmitis.
Corneal infiltration and opacification in severe endophthalmitis necessitates extreme care in obtaining a vitreous biopsy and limits the performance of vitrectomy.
Acute post-cataract endophthalmitis occurs between 1 day and 4 weeks after surgery, presenting as a sudden, severe visual loss.
“In previous years, pain was the most common symptom. But now, with the use of intensive steroids following cataract surgery and with the technical improvements of the procedure, pain is rare at an early stage, and decreased vision is the most common sign,” said Donald J. D’Amico, MD, professor of ophthalmology at Harvard Medical School.
The first step, he said, is to take a vitreous biopsy, which can be done with various techniques.
“There are now some portable instruments that can take an automated sample and combine the advantages of mechanized cutting and manual aspiration. In addition, they can be used outside the operating room,” he said.
The main elements of the treatment of endophthalmitis are medical treatment by intravitreal injections or by systemic drugs, and surgical treatment with vitrectomy.
“Regarding intravitreal antibiotic injection, we have all agreed that a 1-mg dose of vancomycin is the drug of choice for gram-positive infection, but for gram-negative infection, there is some controversy,” Dr. D’Amico said. “I and many other doctors continue to recommend the use of amikacin, 400 µg for gram-negative coverage. Because of concerns of toxicity, some colleagues feel that the use of cefta zidime 2.25 mg is better. However, studies on amikacin have not taken into account the fact that toxicity might be due to overdosage resulting from mistakes or miscalculations in preparation of drug dilutions, and I really think that most cases of amikacin toxicity are really dosage errors.”
The use of intravitreal steroids is also controversial. Some studies have shown damage, and some have shown improvement, Dr. D’Amico said. In his opinion, steroids should be reserved for cases with severe inflammation.
The Endophthalmitis Vitrectomy Study (EVS), ongoing in the United States and often mentioned by Dr. D’Amico, looked at two important issues. One was the use of additional vitrectomy (beyond that needed to take a vitreous biopsy) as a therapy and the second was whether or not systemic antibiotics were useful.
“According to the EVS, vitrectomy was found beneficial only in patients who had a very severe loss of visual acuity, that is, light perception vision only. So it is a guideline that patients who present with better than light perception vision should normally be treated with vitreous biopsy and intravitreal antibiotics, but no additional vitrectomy,” he said.
As far as the use of systemic antibiotics is concerned, Dr. D’Amico ob served that, in his opinion, the EVS does not give a real answer.
“The study used antibiotics that were not designed to treat staphylococcus, which is responsible for the majority of our infections. As a result, they showed no benefit from antibiotics. However, I believe that if they had used the right drug, they might have been successful in certain cases. As new preparations come along, with better systemic and ocular penetration, we’ll see even better results,” he said.
Vitrectomy in endophthalmitis requires skilled, experienced surgeons who can rapidly recognize the stage of the disease and vary the technique accordingly.
“There are patients who we can follow from the beginning of the disease, and in these cases, we can decide if and when it’s the right time to do surgery. In other cases, we are dealing with emergencies, and this gives us very little time to think,” said Dr. Forlini, head of the Pesaro Eye Clinic.
Like most of his Italian colleagues, Dr. Forlini believes that vitrectomy is needed in the vast majority of cases and that it is the safest solution also at an early stage of the disease.
“Endophthalmitis tends to progress in a rapid, uncontrolled manner, and I prefer to be aggressive with it. There are ways of making the procedure quite safe, and very rarely have I had severe complications such as retinal detachment,” he said.
A bubble protects the retina
The main difficulties of vitrectomy in endophthalmitis come from opacification of the cornea, which occurs at the advanced stages of the disease and prevents vision of the ocular fundus.
“If there is still some transparency in the cornea, we can attempt a closed-sky procedure, which is going to be very difficult because we can’t see the retinal plane. However, when there is a complete loss of transparency, there is no choice. We must remove the whole cornea and temporarily replace it with a keratoprosthesis to have access to the internal structures of the eye,” Dr. Forlini said.
For safer surgical maneuvers, he suggested the use of liquid perfluorocarbon.
“The bubble of perfluorocarbon finds its way through the vitreous and sets behind it, between the posterior part of the vitreous and the retina. I can then perform my maneuvers until I reach beyond the center of the vitreous in complete safety, as the bubble protects the retina and holds it down,” he said.
In this way, Dr. Forlini minimizes the risk of retinal detachment, which may occur during the aspiration maneuvers.
“In conditions of poor visibility, the aspiration of the vitreous may exert an attraction on the retina, which is pulled away without you even realizing it,” he said.
In the last stages of vitrectomy, when the retinal plane comes nearer and the surgeon is better oriented inside the eye, the perfluorocarbon liquid is removed, and the final maneuvers are carried out. Dr. Forlini recommended extreme care at this stage, because the retina is often weakened and there is the risk of retinal tears or hemorrhages.
“I use liquid perfluorocarbon also in open-sky procedures, when the vitreous is totally opaque and you don’t know at all where you are, just like when you are driving a car in a thick fog. You grope your way, but at least you know that nothing too bad is going to happen,” he said.
Salvage all you can
In eyes that are so heavily injured, there is often very little that surgery can do for visual acuity. The aim is merely that of saving the bulb.
“When you realize that there is nothing you can do to regain vision, don’t give up, but salvage all you can of these eyes. Concentrate on the ciliary body in particular, and do an accurate cleaning to reduce structural (and esthetic) damage as much as possible,” Dr. Forlini said.
You should not forget, he said, that endophthalmitis patients are otherwise healthy and often young patients.
As medications and surgical techniques are evolving, new hopes are rising.
“There are more and more cases where we can do something to preserve vision,” Dr. D’Amico said. “We are now waiting for the use of specific anticytokine therapy, which should be able to provide a better control of the inflammation.”
Results are steadily improving, he noted.
“In the 40s, prior to the use of intravitreal antibiotics, all eyes with endophthalmitis were lost, and now more than 50% of post-cataract cases have visual acuity of 20/40 or better. This has been an enormous progress. But we need to do better, because there are still too many cases of virulent infection where our actual means are inadequate,” he said.
For Your Information:
- Donald J. D’Amico, MD, can be reached at Massachusetts Eye and Ear infirmary, 243 Charles St., Boston, MA 02114; (617) 573-3291; fax: (617) 573-3698.
- Cesare Forlini, MD, can be reached at U.O. di Oculistica, ospedale San Salvatore, Piazzale Cinelli 4, 61100 Pesaro, Italy; phone and fax: (39) 0721-362466.