Improvement of Siderotic ERG

For fear of endophthalmitis and siderosis, ferrous intraocular foreign bodies are usually removed as soon as they are discovered; markedly reduced, siderotic ERG changes are considered permanent. We report a patient who presented with a chronically retained intravitreal foreign body and significant clinical as well as electrophysiologic signs of siderosis. Only 3 months after surgery, the ERG showed almost complete recovery. If siderosis is not present, adequate and regular follow-up examinations may in certain cases substitute for immediate removal of chronically retained intraocular foreign bodies.

Presence of erythroid and nonerythroid spectrin transcripts in human lens and cerebellum

Spectrin is a major protein of the red cell membrane, and is composed of alpha- and beta-subunits. While spectrin was initially thought to be specific for erythrocytes, similar, but nonidentical peptides have recently been identified in other tissues, including lens, suggesting the existence of a spectrin gene family. To study the nature of spectrin-like peptides in the lens, we examined the transcription of erythroid and nonerythroid spectrin in human lens and cerebellum by direct hybridization with known human alpha- and beta-spectrin cDNA (erythroid probes), as well as with a human alpha-fodrin cDNA (nonerythroid probe). Northern blots of poly(A)+ RNA from erythroid, as well as several nonerythroid cells, and the total RNA from lens, showed that the beta-spectrin cDNA probe hybridized to two distinct bands of 8.6 and 7.4 kb mRNA in human lens, and was present in abundance. The erythroid beta-spectrin 11 kb mRNA transcript was also found in the human cerebellum. The beta-spectrin transcripts from these nonerythroid tissues were found to have different sizes compared to the major erythroid 7.8 kb beta-spectrin mRNA. Human lens contained a 7.5 kb transcript of the erythroid alpha-spectrin subunit. In addition, the human lens was found to have a 7.2 kb alpha-fodrin transcript; while the cerebellum had an 8.5 kb alpha-fodrin mRNA, the same size as that found in other nonerythroid tissues. The abundance of erythroid and nonerythroid spectrin transcripts in lens was significantly greater than in any other tissues examined. These data show that the human lens has abundant erythroid alpha- and beta-spectrin transcripts, as well as a unique alpha-fodrin transcript.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of pupillary dilatation in flash VER testing

Light flash transient visual evoked response (VER) testing is often a part of the perioperative evaluation of eyes with opaque media, and pupillary size in these patients may not be knowable or may be inadvisable to alter. We therefore evaluated transient light flash VER responses before and after pupillary dilation in normal controls and in patients with media opacities to evaluate the effects of pupil size on the amplitude and latency of the recorded VER. Monocular testing was performed bilaterally with a Grass PS-22 photostimulator at the S1 and S16 settings, with monopolar recordings 1 cm above the inion. One hundred twenty-eight 200-msec samplings were recorded and averaged on a Nicolet CA-1000 clinical averager. Latencies were often shorter with the stronger light stimulus, but pupillary dilation did not produce a clear trend toward shorter latencies. Overall, pupillary dilatation did not significantly increase recorded amplitudes, nor did iris color appear to be a factor. These results suggest that, under our testing conditions, pupillary dilatation is not necessary for obtaining reliable transient flash VER recordings.

Leber's congenital amaurosis

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