On the recovery of the electroretinogram after removal of intravitreal copper particles

Prognosis of penetrating eye injuries with posterior segment intraocular foreign body

PURPOSE

To identify the prognostic factors concerning the anatomy and visual acuity of eyes subject to trauma related posterior intraocular foreign body.

PATIENTS AND METHODS

The records of 28 eyes of 27 patients who underwent pars plana vitrectomy and intraocular foreign body removal during a 5 year period were retrospectively reviewed. Ocular trauma score was calculated for each eye.

RESULTS

The most common initial findings were corneal wound (68%), lens injury (50%), retinal lesion (50%), vitreous hemorrhage (25%), and endophthalmitis (14%). Multiple foreign body causing perforating injury with retained posterior segment foreign body occurred in 7% of the cases. The foreign body was found on the surface of the retina in 39% of the cases. Postoperative complications were retinal detachment (46%), proliferative vitreoretinopathy (25%), and phthysis (4%). No eye was enucleated and 1 eye (4%) lost light perception. The final best corrected visual acuity became better or equal to 0.5 Snellen E in 34% of the eyes. The mean follow-up was 19 months (1.5-60 months).

CONCLUSIONS

Prognosis was significantly worse in cases with lower trauma score, initial visual acuity less than 0.1 Snellen E, large foreign body, upset of bacterial endophthalmitis, and with proliferative vitreo-retinopathy. Visual outcomes in our cases were better than estimated follow-up visual acuity based on ocular trauma score parameters.

Comparisons of the amplitude size and the reproducibility of three different electrodes to record the corneal flash electroretinogram in rodents

To compare corneal electrodes commonly used in rodent eyes for repeat and left versus right eye accuracy and variability to record the flash electroretinogram (ERG). Animals studied were eight C57BL/6 mice and eight rats of the Wistar strain. Scotopic ERGs were recorded from eyes of dark-adapted anesthetized rodents to compare a custom-made gold-wire contact lens electrode (CLE), a cotton-wick silver-silver chloride electrode (SCLE), and a coiled stainless steel wire electrode (SSE). Compared to SCLE and SSE. the potentials recorded by CLE are characterized by significantly larger ERG amplitudes and oscillatory potentials in both rats and mice (p <0.0001). In analyzing test-retest data comparing the three different electrodes the coefficient of variation was smaller (range, 10.3-15.5%) and the interclass correlation coefficient (0.77-0.93) showed a better agreement for the CLE. Recording scotopic ERGs with custom-made gold-wire contact lens electrodes records large amplitudes and shows a good reproducibility and reliability to monitor retinal function in rodent eyes.

Eye injuries with metal missiles presenting to an emergency center: a three year study

The authors retrospectively evaluated 33 eye injuries due to metal missiles in 31 patients presenting to our emergency center over the last 3 years. Injuries occurred most frequently when the patients were grinding metal or working on their cars. The type of metal involved in the injury often dictates the type of ophthalmic reaction that will occur. A discussion of intraocular metallic foreign bodies with an emphasis on electroretinograms and metal analysis is presented.

Intravitreal cupriferous foreign bodies: electroretinograms and inflammatory responses

This is a report on the effects of various equally sized copper alloys implanted in the vitreous body of 52 Wistar rats. The main results are as follows: (1) The alloy of 99.9% copper with 0.1% silver (A) destroyed the electroretinogram (ERG) faster than specially purified copper (B). In contrast, copper-zinc alloys (C and D) affected the ERG more slowly than B. This effect is more obvious in alloys containing a large amount of zinc (D). (2) The degree of complication in the anterior segment (iridocyclitis, corneal opacity, hypopyon) and in the vitreous body (intensity and rate of opacity) depend essentially on the type of alloy. The frequency and extent of inflammatory responses decreased in the following order: alloy A, B, C and D.

Surface area sized of intravitreal iron wires: their effects on the electroretinograms of rats

The electroretinogram (ERG) was recorded 20 times over a period of 360 days in 26 albino-rats with implanted intravitreal iron wires ranging in size between 0.15 and 1.2 mm2.

RESULTS

(i) The a- and b-wave amplitudes decreased rapidly within one day after iron wire implantation. During the following week the amplitudes recovered to some extent. In the course of the next few months the a- and b-wave amplitudes of the eyes implanted with the largest iron wires (1.2 mm2) decreased steadily to about 20% by the end of the observation time, whereas in the groups containing smaller iron wires the electroretinographic changes were limited. (ii) Implantation of equally-sized glass splinters reduced the a- and b-wave amplitudes to 65-75% in comparison to the intact fellow eye. Fast recovery of both potentials to 83-93% followed within two weeks. The mean values of the a-wave amplitudes reached nearly 100%, those of the b-wave 90-95% in the next month.

On the recovery of the electroretinogram after removal of intravitreal zinc particles

The influence of intravitreal zinc particles (1.3 mm2) in the eyes of rats caused the amplitudes of the electroretinogram to decrease to about 50% of the initial values within 24 hours, whereas the prolongation of the peak times began only on the third day after particle implantation. The removal of the zinc particles after 30 days led to only partial recovery of the amplitudes, whereas the peak times reached normal values. Dissociated behaviour of the amplitudes and peak times as described here was not found in earlier experiments with intravitreal iron, copper or lead particles of the same size. The extraction of intravitreal zinc particles (1.3 mm2) one day after implantation resulted in a recovery of the amplitudes up to 85%.