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Perplexing Injections 

In EyeNet’s June issue, there was a Journal Highlights summary of the April Archives of Ophthalmology article, (“Prophylaxis of Acute Posttraumatic Bacterial Endophthalmitis.”) In the summary, Soheilian et al. state that intravitreal injection was superior to intracameral injection in preventing endophthalmitis.

Considering the actual findings of the study, this statement is generous. First, intracameral and intravitreal injections were selected for different eye injuries, making comparisons difficult. My truncated version of the article’s Table 2, below, shows that injuries given intravitreal injections of balanced salt solution were more likely to develop endophthalmitis than injuries given intracameral injections (presumably given coincident intraocular foreign bodies).

As the type of injury given intracameral injection had no endophthalmitis in its control group, it is impossible to demonstrate a benefit in the intracameral treatment arm and make a comparison to intravitreal injections.

Timothy R. Harrison, MD
Middlebury, Ind.


Potential

Treatment

Endophthalmitis,

 

Confounder

Groups

No. (%)

Total

Intracameral

Balanced Salt

0

49

Injection

Solution

 

Antibiotic

1 (1.3)

77

Intravitreal

Balanced Salt

8 (6.8)

118

Injection

Solution

 

Antibiotic

0

102


Table 2. Development of Endophthalmitis in Cases vs. Controls Stratified According to Site of Injection.

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The following is a response of the study authors to Dr. Harrison.

We appreciate Dr. Harrison’s close attention. As evident in the table, eyes requiring intravitreal injection were more prone to endophthalmitis. Whether the lower rate of endophthalmitis in treated eyes in the intravitreal vs. the intracameral group is due to prophylactic effect of the antibiotics will remain an unresolved issue.

Eyes receiving intravitreal and intracameral injections do not seem to be comparable groups because the nature of trauma and subsequently the risk of acute posttraumatic bacterial endophthalmitis (APBE) may be different. This is the reason why injection site was a significant confounder in the study and had a considerable effect on the outcomes.

The argument over whether intravitreal injection may be superior to intracameral injection in preventing APBE is open for further studies. We encourage interested readers to access the full-text version of our paper where this issue has been dealt with in more detail.

Masoud Soheilian, MD
Nasrin Rafati, MD
Shahin Yazdani, MD
Tehran, Iran

Editor’s Note: A full-text version of the paper discussed above can be found at archopht.ama-assn.org. Online access requires a fee.

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Thyroid Eye Disease: More Options 

The September Clinical Update (“Thyroid Eye Disease and the Search for Options”) discusses both Graves’ ophthalmopathy and the best approaches for managing thyroid eye disease.

However, it did not mention diplopia, which can be very disturbing and should be treated with orthoptics, surgery or both. Also, proptosis is oftentimes only apparent because it is the lid retraction that gives the appearance of proptosis. This can be alleviated by guanethidine 5 percent solution one to four times a day.

In addition, chemosis and lid edema can be reduced by using Diamox or any other carbonic anhydrase inhibitor such as methazolamide or dichlorphenamide. In my experience, steroids are not too effective and quite problematic as a treatment option. To test their effectiveness, a trial of retrobulbar steroids can be followed by a high dosage (120 mg) of prednisone for one week. The secondary side effects of radiation make this modality extremely undesirable considering that the results are equivocal.

Heskel M. Haddad, MD
New York

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Correction 

The October Blink credited Michael P. Kelly for the pseudoexfoliation syndrome text.

It should also have given credit to Molly Walsh, MD, and Leon W. Herndon, MD, at Duke University in Durham, N.C. EyeNet regrets the error.

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