The Pupil Light Reflex in Leber's Hereditary Optic Neuropathy: Evidence for Preservation of Melanopsin-Expressing Retinal Ganglion Cells

Abstract

Citation: Moura ALA, Nagy BV, La Morgia C, et al. The pupil light reflex in Leber's hereditary optic neuropathy: evidence for preservation of melanopsin-expressing retinal ganglion cells. Invest Ophthalmol Vis Sci. 2013;54:4471-4477. DOI: 10.1167/iovs.12-11137 PURPOSE. To investigate the pupillary light reflex (PLR) of patients with severe loss of vision due to Leber's Hereditary Optic Neuropathy (LHON) in the context of a proposed preservation of melanopsin-expressing retinal ganglion cells (mRGCs). METHODS.Ten LHON patients (7 males; 51.6 6 14.1 years), with visual acuities ranging from 20/400 to hand motion perception and severe visual field losses, were tested and compared with 16 healthy subjects (7 males; 42.15 6 15.4 years) tested as controls. PLR was measured with an eye tracker and the stimuli were controlled with a Ganzfeld system. Pupil responses were measured monocularly, to 1 second of blue (470 nm) and red (640 nm) flashes with 1, 10, 100, and 250 cd/m 2 luminances. The normalized amplitude of peak of the transient PLR and the amplitude of the sustained PLR at 6 seconds after the flash offset were measured. In addition, optical coherence topography (OCT) scans of the peripapillary retinal nerve fiber layer were obtained.RESULTS. The patient's peak PLR responses were on average 15% smaller than controls (P < 0.05), but 5 out of 10 patients had amplitudes within the range of controls. The patients' sustained PLRs were comparable with controls at lower flash intensities, but on average, 27% smaller to the 250 cd/m 2 blue light, although there was considerable overlap with the PLR amplitudes of control. All patients had severe visual field losses and the retinal nerve fiber layer thickness was reduced to a minimum around the optic disc in 8 of the 10 patients.CONCLUSIONS. The PLR is maintained overall in LHON patients despite the severity of optic atrophy. These results are consistent with previous evidence of selective preservation of mRGCs.

A Positive Association Between Intrinsically Photosensitive Retinal Ganglion Cells and Retinal Nerve Fiber Layer Thinning in Glaucoma

“…8 In the present study, the 250 cd/m 2 blue flash stimulus specifically isolated the activity of ipRGCs, as demonstrated in previous studies. 7,28,48 However, the real mechanism of damage in these cells was not investigated; thus, further studies should be conducted to better understand the resistance properties of these cells.…”

“…4,6 However, descriptions of the relative preservation of the number of ipRGCs are available. 7,8 In 2002, ipRGCs were described as a new type of photoreceptor 5,[9][10][11][12][13] that expresses the photopigment melanopsin (also known as opsin 4, or OPN4). These cells account for approximately 1% to 3% of the total RGC population in the human retina.…”

Intrinsically Photosensitive Retinal Ganglion Cell Activity Is Associated with Decreased Sleep Quality in Patients with Glaucoma

“…Another important point is that because of the diversity of RGCs, the relative preservation of a number of different types of RGCs (e.g., ipRGCs) has been described. 26,53 Some previous researchers have reported that ipRGCs were resistant to injury and remained stable until the end stage of the disease. However, a recent study reported the opposite results, concluding that these cells could be lost over the course of the disease.…”

En tenåring med akutt bilateralt synstap

“…En tredel av LHON-pasientene har imidlertid oftalmoskopisk normale papiller når synstapet debuterer. Et annet differensialdiagnostisk funn er visuell-pupillaer dissosiasjon, som betegner bevart pupillerefleks til tross for betydelig synsaffeksjon (9). Synstapet er gjerne uttalt og permanent, men i noen tilfeller ses spontan bedring.…”