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Purpose: The purpose of this study was to describe a new modification for big-bubble deep anterior lamellar keratoplasty (DALK) using pneumatic pressure to detach Descemet membrane (DM) via air injection followed by ophthalmic viscoelastic device (OVD) injection., Methods: After failure of big-bubble formation after air injection, OVD was injected from a different site other than the previous air injection using a 27-gauge cannula to detach DM, called air-visco bubble (AVB) DALK technique. The technique was used in 7 human corneoscleral rims that were investigated with anterior segment optical coherence tomography and histopathology and in 69 eyes that underwent DALK surgeries., Results: Big-bubble formation was noted in 4 of 7 of the donor corneoscleral rims. The anterior segment optical coherence tomography showed big-bubble formations together with intrastromal OVD accumulation. The histology of the donor corneas showed microdetachments at the DM in the periphery, deep intrastromal separation, and big-bubble formation filled with OVD. One hundred forty-one of 210 eyes (67%) underwent successful DALK with only air injection, and 69 of 210 eyes (33%) underwent AVB technique when a big bubble was not achieved with only air injection. All the corneas showed a clear interface with good wound healing when DM was bared with the AVB DALK technique., Conclusions: Additional OVD injection to detach DM may be useful in cases where air injection fails. Also, creating small DM detachments with air injection may facilitate the formation of a big bubble with further OVD injection.

Purpose: To report the clinical, histopathologic, and confocal findings of corneal siderosis., Methods: A 35-year-old man presented after a car battery explosion with diffuse left corneal anterior stromal pigment deposition and an intraocular metallic foreign body of the left iris. The corneal pigment was analyzed by confocal microscopy and a lamellar corneal biopsy., Results: Confocal microscopy showed the pigment to be highly reflective material in the corneal stroma with greatest density anteriorly. Histologic examination revealed the pigment to be iron with a diagnosis consistent with corneal siderosis., Conclusions: Corneal biopsy with Prussian blue established siderosis as the etiology of corneal pigmentation. A short delay in the removal of the foreign body contributed to the development of siderosis. The location of the foreign body on the iris may account for the predominant corneal involvement and relative sparing of the retina. Confocal microscopy may be useful in the evaluation of corneal siderosis.

A great deal of controversy and concern exists over potential transmission of central nervous system diseases by corneal transplant. The purpose of this study was to evaluate the available data relative to this question, pertaining especially to transmission of infectious dementia. From these data, determination of conveyance risks are possible, and rational policies for donor inclusion criteria can be constructed. Retrospective analysis of available published data regarding transmission of infectious dementias was performed. Risk of disease transmission was calculated from population data. Of the various forms of dementia, only rabies, hepatitis B, and Creutzfeldt-Jakob disease (CJD) have been transmitted by corneal transplantation. Transmission of the first two viruses is preventable by serologic testing. Prevention of CJD transmission relies on clinical history. Despite the possibility of transmission and the lack of available testing, slow virus disease (CJD) has been transmitted only once. That this case represents an extremely rare event is supported by a lack of successful transmission via corneal transplant in monkeys; lower levels of infectious agent in cornea than in brain; lack of successful transmission of similar human dementias, including Alzheimer's disease to primates; the apparent requirement for homozygosity at codon 129 of chromosome 20 for transmission; lack of transmission in 5-10% of CJD cases even after brain inoculation; and low numerical risk of transmission based on population data. Only 0.5-4 CJD infected donors per year would be expected. Current Eye Bank Association of America criteria for donor exclusion based on suspicious history are adequate to protect against accidental conveyance of transmissible dementia.