Article A case of fundus albipunctatus in both eyes


 Background

This case was first recorded in fundus albipunctatus with multimodal imaging (optical coherence tomography(OCT), angio-OCT, multicolor-OCT, fluorescence angiography), vision field and electrophysiological recordings.

Case presentation

The authors present a 52-year-old Chinese female who suffered night blindness for years. With multimodal images, the fundus images and full-field electroretinography after standard and prolonged dark adaption were consistent with fundus albipunctatus. Disease targeted gene test was not performed. Other imaging method seems to have minimal changes.

Conclusions

It is an observational case report about characteristic ophthalmic findings in fundus albipunctatus.


Background
Fundus albipunctatus (FA) is a rare autosomal recessive macular dystrophy, characterized by a myriad of numerous small white-yellow dots at the level of the pigment epithelium, sprinkled about the posterior pole and midperiphery of the retina. [1,2] FA patients suffer the night-blindness, with little visual acuity or visual eld or color vision defect. The electrophysiological responses present that FA patient needs a long dark-adaptation period to obtain the maximum scotopic responses. With time, FA and its manifestations may progress. FA is caused mostly by mutations in the RDH5 gene, which encode the enzyme called 11cis retinal dehydrogenase in the visual cycle. [3.4] This case was aimed to display the fundus albipunctatus with multimodal imaging (optical coherence tomography(OCT), angio-OCT, multicolor-OCT, uorescence angiography), vision eld and electrophysiological recordings.

Case Presentation
Female patient, 52-year-old, has kept complaining about the night-blindness since childhood. Same symptoms were not found in her family. The best corrected vacuity was 20/25 in both eyes, with -3.00 DS in the left eye and -2.50DS/-0.50DC X110 in the right eye. Intraocular pressure was within the normal eld.
Through the slit-light examination, no positive sign was found. Fundus examination showed with wellde ned optic disc (C/D ratio was about 0.3) and vessels, attened macular area, no obvious pigmentation, while widely diffused white dots. The margin of the dots began from the nasal optic disc, and the temporal side outside the arch of the blood vessels, then reached the equator of the retina. These dots were detected symmetrical distribution in both eyes with almost same size. (Fig. 1) OCT revealed that in the dots lesion, multiple tiny hump-like substances with high re ective, some of which had ruptured the Ellipsoid zone, were found at the level of pigment epithelium. (Fig. 2) Multicolor-OCT revealed the distribution of the white, white and dark lesions in blue, green and red re ectance respectively, corresponded roughly to color photograph. (Fig. 3) The central 30° visual eld in both eyes showed minor and local periphery visual defect, which may be caused by cataract. (Fig. 4) Angio-OCT in diffused hyper-uorescence, some may correspond to the dots, and low background uorescence, without leakage. (Fig. 6) Electroretinogram(ERG) showed in dark-adapted ERG the amplitude of a-and b-waves remarkably declined (almost no responses). In the light-adapted ERG white 30 Hz icker showed reduced amplitudes as well. The scotopic ERG recorded after a long (3-hour) dark-adapted period in the left eye showed markedly improved rod-speci c and combined ERG. (Fig. 7) Discussion And Conclusions FA, as a special kind of congenital stationary night blindness (CSNB) [5] , characterized by its distinct fundus, dark-adaptation curve and ERG responses. As to its pathogen, present studies have focused on the Genes. Mostly, mutations in the RDH5 gene [6] (11-cis retinol dehydrogenase) affected retinoid metabolism (11-cis retinol dehydrogenase) in the visual cycle, leading to FA features. However, other genes mutation had been reported, as the RLBP1 gene [7] (retinaldehyde binding protein 1) and RPE65 gene [8] (RPE-speci c protein). 11-cis retinol dehydrogenase, produced in the smooth endoplasmic reticulum of the pigment epithelium cells, has revealed great importance in the visual cycle and the production and accumulation of lipofuscin in the pigment epithelium cells. [9] So, the impairment of pigment epithelium cells accounts for not only the lesion position, but also the dark blindness symptoms. Strictly, FA is not totally stationary. Resent reports had detected the dysfunction of cone cells and the disruption of Ellipsoid zone in OCT. [10,11] Nonetheless, the autosomal dominant inheritance was reported before. However, in this report the family refused to perform genetic test. [12] The most confusing differential diagnosis of FA is retinitis punctata albescens. In 1910, Lauber [1] rstly named FA and differentiate it from retinitis punctata albescens. The latter one, though shows similar dark blindness symptoms and white dots, has narrowing visual eld, Retinitis Pigmentosa signs (pigmentation with bone-cells like, thin retinal vessels, disc with yellow-wax like) in the fundus, no recoverable ERG responses, and progressive visual impairment in both dark and light. The main points of FA diagnosis and its differential diagnosis were mostly found out by analysis of speci c ophthalmic features. The psychological characteristics of the disease shows a dark adaptation delay---abnormal ERG, and declined amplitudes of cone and rod ERG, which would back to normal after 30-40 minutes. [13] Signi cant decline, but after a long enough period of dark adaptation can be to return to normal. In this report, we have presented multiple ophthalmic examinations to show the gure of FA more in detail. Besides traditional examinations (visual eld, ERG, dark-adaption test, uorescence angiography and OCT), we further performed multicolor-OCT and angio-OCT. As the pathology of FA goes, there were little vascular change sign in the macular area. However, multicolor-OCT revealed abnormal layers of retina enface, representing the accumulation of lipofuscin in retinal pigment epithelium cells, which corresponded to the hyperre ective lesions on OCT. The white dots in the fundus varied with age and genotype. [14] With time, it may fade away in patients with FA or after uveitis. Further observations were not included in this report. Consent for publication Written informed consent was obtained from the patient for publication of this Case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.
Availability of data and material Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.

Figure 2
Optical coherence tomography. In the both eyes, macular retina structure were normal (superior right and superior left). Outside the macular area (interior right and interior left), at the level of pigment epithelium, there were some hump-like substances with high re ective, some of which had ruptured the Ellipsoid zone (red arrow).

Figure 3
Multicolor-optical coherence tomography. Left photo: OD; Right photo: OS. Multicolor-OCT revealed the distribution of the white, white and dark lesions in blue, green and red re ectance respectively, corresponded roughly to color photograph.
Page 8/10      Electroretinogram. A: ERG-rst time; B: ERG-second time, after 3 hours. In the rst time, dark-adapted ERG, combined ERG, oscillatory potentials ERG: the amplitude of a-, b-and o-waves were remarkably declined (a-, and b-waves almost no responses). light-adapted ERG with 30 Hz icker: minor reduced amplitudes of b-waves. Only cone-relied ERG: almost normal. In the second time, which was after 3 hours, the ERG recorded markedly improved rod-speci c and combined ERG.