Inadvertent Viscoelastic Separation of the Pre-Descemet (Dua) Layer in Deep Anterior Lamellar Keratoplasty With Structural Features Revealed by Polarization Microscopy.

INTRODUCTION: Deep anterior lamellar keratoplasty (DALK) is a corneal transplant technique that removes the host stroma down to either the pre-Descemet (Dua) layer or Descemet membrane. It is most common for the big bubble technique to create a cleavage plane between the posterior stroma and the pre-Descemet layer. This is advantageous because the pre-Descemet layer has been found to be much stronger than Descemet membrane, and makes the procedure easier to perform. In this report, we present an uncommon viscoelastic-related complication of DALK that resulted in excising the pre-Descemet layer and allowing it to be studied using polarization microscopy. METHODS: DALK was performed using a standard big bubble technique. Postoperatively, a double anterior chamber was found to have been created by the inadvertent passage of an ophthalmic viscoelastic device (OVD) through the pre-Descemet layer. This resulted in the OVD being trapped between the pre-Descemet layer and Descemet membrane. The pre-Descemet layer was then resected in a subsequent operation. The pre-Descemet layer and posterior stroma were studied by polarization microscopy using Sirius Red histochemical staining to elucidate the orientation of the collagen fibers. RESULTS: The pre-Descemet layer is composed of lamellar arrays of collagen that have consistent polarization properties within each layer but show variable polarization of the strands, indicative of anisotropic strand orientation. The degree of variable polarization of the pre-Descemet layer is distinct from the overlying posterior stroma. CONCLUSIONS: Injecting an OVD into a big bubble in DALK may result in it being trapped between the pre-Descemet layer and Descemet membrane. The pre-Descemet layer shows alternating layers of varying polarization of collagen. This anisotropic structure helps explain the basis for the additional strength that the pre-Descemet layer is known to have.

Treatment of ocular Demodex infestation with topical ivermectin cream.

Purpose: To evaluate the use of ivermectin 1% cream for the treatment of sleeves associated with Demodex blepharitis. Observations: A retrospective chart review was conducted on patients with moderate to dense sleeves secondary to Demodex folliculorum, who were treated with one or two applications of topical ivermectin 1% cream. Those who had been documented photographically pre- and post-treatment were evaluated. In this series of 5 cases, ivermectin 1% cream was highly effective in reducing or eliminating sleeves, which is the primary clinical sign of D. folliculorum infestation of the eyelids. Conclusions and Importance: A single or double application of ivermectin 1% cream is well tolerated and highly effective in reducing or eliminating the characteristic sleeves associated with Demodex blepharitis. The use of ivermectin 1% cream merits further investigation.

Characteristics of untreated AIDS-related cytomegalovirus retinitis. I. Findings before the era of highly active antiretroviral therapy (1988 to 1994).

PURPOSE: To identify factors related to variations in the appearance of untreated AIDS-related cytomegalovirus (CMV) retinitis in severely immunodeficient individuals before the availability of highly active antiretroviral therapy (HAART) and to draw inferences regarding early events in the natural history of CMV retinitis based on clinical findings. DESIGN: Retrospective, observational case series. METHODS: We evaluated a series of 100 adult patients with AIDS and newly diagnosed CMV retinitis before the HAART era who were not being treated with specific anti-CMV therapy. Demographic factors, ophthalmic findings, and the influence of drug therapy (zidovudine, acyclovir) on lesion characteristics were evaluated. Lesion border opacity was scored using a four-point scale of severity. RESULTS: Lesions could be categorized by type (fulminant/edematous or indolent/granular) in only 66% of eyes. Severe lesion border opacity (4+) was related to presence of zone 1 lesions (P = .032) and greater extent of disease (P = .004). Acyclovir use was associated with less severe opacity (P = .029) and less zone 1 involvement (P = .016). Early lesions were adjacent to vessels in 73% of eyes; the fovea was involved in 13% of eyes. CONCLUSIONS: Lesion location and drug use that affects virus activity may influence the severity of lesion border opacity, a measure that may be more useful than lesion type in future clinical studies of CMV retinitis. In contrast to earlier concepts, CMV retinitis does not seem to be a fovea-sparing disease. Findings in this study can serve as a reference for investigations into possible changes in CMV retinitis since the introduction of HAART.