Effects of subretinal injection of patent blue and trypan blue in rabbits

PURPOSE: To investigate the histologic and clinical effects of subretinal injection of patent blue (PB) and trypan blue (TB) in rabbits. METHODS: Dutch-belted rabbits (n=8) were vitrectomized followed by subretinal injection of 2.4 mg/ml PB (285 mOsm) and 1.5 mg/ml TB (312 mOsm); balanced salt solution (BSS) (300 mOsm) served as the control. Animals were examined 6, 12, and 24 hr and 14 days after the procedure by fluorescein angiography (FA) and indirect ophthalmoscopy; for retinal toxicity, histologic evaluation studies were performed by light and transmission electron microscopy. RESULTS: FA examination demonstrated window defects suggestive of retinal pigment epithelium (RPE) atrophy in positions of subretinal TB injection, but this was not observed after subretinal injection of PB or BSS. Histologic evaluation disclosed only minimal abnormalities on the photoreceptor outer segment (POS) after subretinal injection of BSS during all follow-up. Subretinal injection of PB caused POS and photoreceptor inner segment (PIS) abnormalities 12 and 24 hr after surgery as well as outer nuclear layer (ONL) damage 14 days after surgery. Subretinal TB injection resulted in POS and PIS damage at 12 hr follow-up. The ONL damage was observed 24 hr after surgery; additionally, POS, PIS, ONL, and RPE abnormalities were observed 14 days after surgery after TB injection. CONCLUSIONS: Subretinal injection of TB induced more significant clinical and histologic damage of neurosensory retina/RPE than did PB or BSS. Future human studies are necessary to access the clinical relevance of these in vivo experiments.     

Corneal edema and permanent blue discoloration of a silicone intraocular lens by methylene blue.

BACKGROUND AND OBJECTIVE: To report a silicone intraocular lens (IOL) stained blue by inadvertent intraoperative use of methylene blue instead of trypan blue and the results of experimental staining of various lens materials with different concentrations of the same dye. MATERIALS AND METHODS: A "blue dye" was used to enhance visualization during capsulorhexis in a patient undergoing phacoemulsification with implantation of a three-piece silicone lens. Postoperatively, the patient presented with corneal edema and a discolored IOL. Various IOL materials were experimentally stained using methylene blue. Sixteen lenses (4 silicone, 4 hydrophobic acrylic, 4 hydrophilic acrylic, and 4 polymethylmethacrylate) were immersed in 0.5 mL of methylene blue at concentrations of 1%, 0.1%, 0.01%, and 0.001%. These lenses were grossly and microscopically evaluated for discoloration 6 and 24 hours after immersion. RESULTS: The corneal edema resolved within 1 month after the initial surgical procedure. After explantation, gross and microscopic analyses of the explanted silicone lens revealed that its surface and internal substance had been permanently stained blue. In the experimental study, all of the lenses except the polymethylmethacrylate lenses were permanently stained by methylene blue. The hydrophilic acrylic lenses showed the most intense blue staining in all dye concentrations. CONCLUSIONS: This is the first clinicopathological report of IOL discoloration due to intraocular use of methylene blue. This and other tissue dyes may be commonly found among surgical supplies in the operating room and due diligence is necessary to avoid mistaking these dyes for those commonly used during ocular surgery.     

Permanent blue discoloration of a hydrogel intraocular lens by intraoperative trypan blue

A 79-year-old white man had cataract surgery in the right eye with implantation of an Acqua intraocular lens (IOL) (Mediphacos). Trypan blue 0.1% was used during surgery to stain the anterior capsule and enhance the contrast during capsulorhexis. Seven days after surgery, the patient presented with "dark and double" vision (monocular diplopia). The IOL was decentered superiorly and appeared dark blue. The lens was explanted 2 months after surgery and sent for gross and microscopic analyses in a dry state and after hydration. The same analyses were performed on 2 unused lenses of the same design that had been immersed in diluted trypan blue solutions (0.01% and 0.001%). On the explanted lens, the dark blue staining was denser in the optic, especially in its periphery. The blue discoloration could not be removed after 24 hours of lens immersion in a balanced salt solution at 37 degrees C. Permanent staining of the unused lenses was also obtained after immersion in the trypan blue solutions.     

Cobalt blue light unit filter - A smartphone attachment for blue light photography

Purpose:The aim of this study was to carry out blue light photography of fluorescein-stained corneas using a novel smartphone attachment.Methods:A smartphone attachment known as the cobalt blue light unit (C-BLU) was developed. It can filter out all wavelengths of light except the blue light emerging from the flashlight of a smartphone. A pilot study was carried out wherein the images captured with the C-BLU system were compared with slit-lamp photographs of the same patients. This setup was then used to photo document fluorescein-stained corneas in various clinical settings assembled at point-of-care.Results:Many pathologies of the fluorescein-stained cornea were captured using the C-BLU filter. It was used effectively in various settings (remote eye camps, intensive care units (ICU), pediatric group, corneal trauma triaging, etc.). C-BLU was assembled and used by optometrists and ophthalmology residents. The images captured were used for documenting, assisting in the treatment, and also for telecommunication of the patients’ findings.Conclusion:C-BLU is a low-cost pocket-size filter which is easy to use with a modern smartphone without any technical expertise needed to obtain a clear image of fluorescein-stained pathological corneas.     

Human and macaque blue cones studied with electroretinography

The spectral sensitivity of the human and macaque blue cone system was measured using an electroretinographic criterion response. It was necessary to take very low criteria (about 1 μV) since the blue system was proved to show a low maximum response. The human and macaque blue cone curve have distinctly different peak wavelengths of 432 and 440 nm respectively. The waveform of the blue system response to 10 msec flashes appeared very similar to that of the long wavelength mechanisms, although a 5–10 msec longer latency was observed. At higher adaptive states the blue and red-green responses showed distinct differences.     

亚甲蓝及粘弹剂在泪囊鼻腔吻合术中的应用

目的:探讨亚甲蓝及粘弹剂在泪囊鼻腔吻合术中的应用价值。方法:对慢性泪囊炎患者21例21眼(其中6例6眼为小泪囊慢性泪囊炎)施行泪囊鼻腔吻合手术,术中应用亚甲蓝及粘弹剂。术后随访3mo～1a,观察手术疗效。结果:所有21眼中治愈19眼,好转2眼,治愈率90.5%,总有效率100.0%。其中6眼小泪囊慢性泪囊炎中治愈4眼,好转2眼。结论:亚甲蓝及粘弹剂在泪囊鼻腔吻合术中的应用可有效提高手术成功率,小泪囊慢性泪囊炎可作为泪囊鼻腔吻合术的手术适应证。     

Brilliant blue G selectively stains the internal limiting membrane/brilliant blue G-assisted membrane peeling

PURPOSE: To report the use of the dye brilliant blue G (BBG) for staining of the internal limiting membrane (ILM) during macular hole (MH) and epiretinal membrane (ERM) surgery. METHODS: This study was designed as an interventional, noncomparative, prospective, clinical case series. Twenty eyes from 20 consecutive patients with MH or ERM underwent BBG-assisted ILM and ERM removal. In MH cases, a posterior vitreous detachment was created, followed by the injection of 0.25 mg/mL BBG solution into the vitreous cavity and immediate washout of the BBG. This technique improved visualization of the ILM, enabling peeling and surgery to be performed successfully. However, in ERM cases, staining of the ERM could not be confirmed at this concentration. Finally, the ILM including the ERM was removed in all cases. Preoperative and postoperative ophthalmic examinations were performed. RESULTS: Postoperatively, 17 patients (85%) had visual acuity improved by at least 2 Snellen lines. No adverse effects were observed postoperatively during the observation period (mean follow-up +/- SD, 7.3 +/- 1.0 months). CONCLUSIONS: BBG selectively stains the ILM. This technique can facilitate the management of MH and ERM surgery without any adverse effects, as was shown in this short-term study.     

蓝光损伤视网膜的机制及防护

蓝光是自然光线的重要组成部分,其波长主要介于400～500nm,是一种短波长光,它是高能可见光谱的一部分。蓝光损伤指的是由这一波长的辐射照射后引起的光化学作用,导致视网膜的损伤。可见光中蓝光对视网膜敏感性最高、穿透力最强,因而产生的光化学损伤作用最强,其中最主要损伤的是视网膜色素上皮细胞(RPE)和视网膜感光细胞。目前针对于蓝光的防护的研究已经逐步开展。本文依据现已证实的蓝光损伤视网膜的机制对其防护机制研究进展进行综述。