J Korean Ophthalmol Soc.  2011 May;52(5):603-609. 10.3341/jkos.2011.52.5.603.

Retinal Changes in White Rabbits after Exposure to the Light of an Operating Microscope

• Lee JK
• Kim HY
• Cho HK

• KMID: 2214581
• DOI: http://doi.org/10.3341/jkos.2011.52.5.603

Abstract

PURPOSE
This study was performed to investigate the potential damage to white rabbit retinas caused by an operating microscope light.
METHODS
A total of 18 white rabbits were exposed to the light of an operating microscope for 60 minutes. Fundus examination, fluorescein angiography (FAG), and electroretinogram (ERG) were performed before exposure and 1 hr, 1 day, 7 days and 14 days afterward to allow for serial comparisons. Light and electron microscopic examinations were performed to evaluate the changes in the rabbit retinas over time.
RESULTS
Signs of retinal damage upon fundus examination and FAG were not found before or after exposure to the light of an operating microscopy. ERG, however, showed significant reduction in the dark-adapted rod response 1 hour after light exposure, and significant decline in the amplitude of the maximal combined response a- and b-wave 1 day after light exposure in the rabbit retinas. ERG findings returned to the pre-exposure level after 2 weeks. Ultrastructural injury to the photoreceptor outer segments and the retinal pigmented epithelium, observed using transmission electron microscopy, recovered to the pre-exposure state after 2 weeks.
CONCLUSIONS
The risk of retinal damage should be considered as an early result of exposure to the light of an operating microscope, even in normal retinal findings.

Keyword

Electroretinogram; Operating microscope; Photoreceptor; Phototoxicity; Retinal pigment epithelium

MeSH Terms

Dermatitis, Phototoxic
Electrons
Epithelium
Fluorescein Angiography
Humans
Light
Microscopy
Microscopy, Electron, Transmission
Rabbits
Retina
Retinal Pigment Epithelium
Retinaldehyde
Retinaldehyde

Figure

• 

  Figure 1. Fundus photographs before (A) and one day after light exposure (C). There are no abnormal findings on the posterior pole. Fluorescein angiophotographs before (B) and one day after light exposure (D) shows no hypo- and hyperfluorescence area and leakage findings.

• 

  Figure 2. Electron microscopic findings of the rabbit retina. A. Before light exposure, the photoreceptor inner segment (PRis) and outer segment (PRos) are compact. An external limiting membrane is well visible. The connecting points of the PRis and Pros are located almost on the same level. The retinal pigment epithelium (RPE) microvilli surround the PRos in good condition (A). One hour after light exposure, the PRis exhibit enlargement and mitochondrial swelling. The connecting points of the PRis and PRos are not on the same level in contrast to figure A. There are marked mitochondrial swelling of the PRis, shedding of the PRos, scarcity of the RPE microvilli, disconnection between the RPE microvilli and PRos, RPE flattening. A phagocytosed PRos is visible (B). One day after light exposure, the PRis shows many cytoplasmic vacuoles. The change in PRos and RPE microvilli are more prom-inent compared to those of figure B (C). One day after light exposure, the RPE microvilli surround the PRos. The scarcity of the RPE microvilli is still visible. There are several lipofuscin in the cytoplasm of the RPE (D). One week after light exposure, the RPE contains many cytoplasmic phagocytosed PRos. The architecture of the PRis and PRos is well preserved. The RPE microvilli surround the PRos as shown in pre-light exposure figure (E). Original magnification: (A, B, C, E) × 2000; (D) × 8200. PRis = photoreceptor inner segment; Pros = photoreceptor outer segment; RPE = retinal pigment epithelium.

Reference

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