Unilateral COVID-19-associated vasculitic central retinal vein occlusion: phlebitis with subhyaloid, intraretinal and subretinal hemorrhages.

PURPOSE: To describe unilateral vasculitic central retinal vein occlusion (CRVO) in a young adult whose vision problems preceding system symptoms of COVID-19 infection. METHODS: Observational clinical case report. RESULTS: A 39-year-old immunocompetent male without prior ocular disease presented for vitreoretinal care complaining of decreasing vision in his right eye for two weeks. Headaches, pharyngitis and coughing began four days after his visual symptoms. COVID-19 testing was negative prior to initial vitreoretinal evaluation and positive afterward. Dilated and tortuous major retinal veins in his right eye had prominent perivascular sheathing. A large subhyaloid hemorrhage spanned the macula. Subretinal hemorrhages were present in areas of sheathing and diffuse nerve fiber layer hemorrhages were arrayed in the distribution of the radial peripapillary capillary plexus. Laboratory tests for inflammatory diseases were negative. The patient was hospitalized for COVID-19 pneumonia a few days after his initial vitreoretinal evaluation. Pars plana vitrectomy was performed for persistent subhyaloid hemorrhage eight weeks after his hospitalization. The visual acuity in the patient's right eye improved from CF to 20/30 post-operatively. CONCLUSION: The patient's findings are consistent with an atypical CRVO which we hypothesize to be of vasculitic origin because of prominent associated retinal phlebitis and venous sheathing. Concomitant subhyaloid, nerve fiber layer and subretinal hemorrhages involved the superficial and deep retinal vascular complexes. The patient's COVID-19-related hospitalization and systemic management delayed surgical management of his subhyaloid hemorrhages but a good visual result was achieved despite persistence of macular preretinal blood for three months.

Half-Fluence, Half-Dose Photodynamic Therapy: Less Direct Damage but More Inflammation?

Objective: To present clinical findings and multimodal imaging of three patients who developed bacillary layer detachments (BALADs) shortly after half-fluence, half-dose (HFHD) verteporfin photodynamic therapy (PDT). Methods: Retrospective observational case series. Three patients were treated with HFHD-PDT for (1) macular neovascularisation five years after resolved central serous chorioretinopathy (CSC), (2) persistent serous retinal detachment (SRD) from chronic CSC, and (3) neovascular age-related macular degeneration with persistent SRD despite intravitreal anti-VEGF therapy. Results: Each patient developed a BALAD after HFHD-PDT. Acute fulminant exudation caused subretinal fluid expansion into the inner photoreceptor layer, cleaving myoid from ellipsoid zones in the central macula. Subretinal fluid and the BALADs subsequently resolved over 6-8 weeks. Conclusions: The subretinal fluid and BALAD following HFHD-PDT were transient and did not cause photoreceptor damage over a 6-month follow-up period. We speculate that the reduced-impact HFHD protocol decreases direct tissue damage but increases proinflammatory cytokines. The long-term pathophysiological consequences of the resolved BALADs are unknown.

BACILLARY LAYER DETACHMENT AFTER PHOTODYNAMIC THERAPY FOR CENTRAL SEROUS CHORIORETINOPATHY.

PURPOSE: To report the clinical and optical coherence tomography findings of a patient with chronic central serous chorioretinopathy who developed a short-term bacillary layer detachment after photodynamic therapy (PDT). METHODS: A 56-year-old man presented with metamorphopsia and 20/100 visual acuity in his right eye. He was diagnosed with active, chronic central serous chorioretinopathy based on clinical findings and multimodal imaging. His visual problems and retinal findings persisted for 3 months before he was treated with half-fluence, half-dose verteporfin PDT. RESULTS: The patient had a prominent decrease in his vision postoperatively. Two days after treatment, multimodal imaging showed a marked increase in exudation that merged preoperative neurosensory retinal detachments. A prominent subfoveal bacillary layer detachment was also present. The subretinal fluid and bacillary layer detachment resolved over the next 8 weeks, with a return of visual acuity to its baseline level and normalization of retinal structures except for a small zone of subfoveal ellipsoid zone and interdigitation zone disruption. CONCLUSION: Half-fluence, half-dose verteporfin PDT caused a fulminant increase in subretinal fluid and an associated subfoveal bacillary layer detachment. We hypothesize that chronic central serous chorioretinopathy-related chorioretinal dysfunction contributed to the severe PDT-induced local inflammatory reaction that caused the patient's bacillary layer detachment. Hyperacute choroidal exudation too fulminant for containment in subretinal space extended into and exceeded photoreceptor inner segment tensile strength, cleaving the myoid layer and/or dissecting it from the ellipsoid layer. This finding broadens the causality spectrum of bacillary layer detachments and vision losses that can follow PDT.

Scanning laser ophthalmoscopy retroillumination: applications and illusions.

Scanning laser ophthalmoscopes (SLOs) are used widely for reflectance, fluorescence or autofluorescence photography and less commonly for retroillumination imaging. SLOs scan a visible light or near-infrared radiation laser beam across the retina, collecting light from each retinal spot as it's illuminated. An SLO's clinical applications, image contrast and axial resolution are largely determined by an aperture overlying its photodetector. High contrast, reflectance images are produced using small diameter, centered apertures (confocal apertures) that collect retroreflections and reject side-scattered veiling light returned from the fundus. Retroillumination images are acquired with annular on-axis or laterally-displaced off-axis apertures that capture scattered light and reject the retroreflected light used for reflectance imaging. SLO axial resolution is roughly 300 µm, comparable to macular thickness, so SLOs cannot provide the depth-resolved chorioretinal information obtainable with optical coherence tomography's (OCT's) 3 µm axial resolution. Retroillumination highlights and shades the boundaries of chorioretinal tissues and abnormalities, facilitating detection of small drusen, subretinal drusenoid deposits and subthreshold laser lesions. It also facilitates screening for large-area chorioretinal irregularities not readily identified with other en face retinal imaging modalities. Shaded boundaries create the perception of lesion elevation or depression, a characteristic of retroillumination but not reflectance SLO images. These illusions are not reliable representations of three-dimensional chorioretinal anatomy and they differ from objective OCT en face topography. SLO retroillumination has been a useful but not indispensable retinal imaging modality for over 30 years. Continuing investigation is needed to determine its most appropriate clinical roles in multimodal retinal imaging.

The Blue Light Hazard Versus Blue Light Hype.

PURPOSE: The blue light hazard is the experimental finding that blue light is highly toxic to the retina (photic retinopathy), in brief abnormally intense exposures, including sungazing or vitreoretinal endoillumination. This term has been misused commercially to suggest, falsely, that ambient environmental light exposure causes phototoxicity to the retina, leading to age-related macular degeneration (AMD). We analyze clinical, epidemiologic, and biophysical data regarding blue-filtering optical chromophores. DESIGN: Perspective. METHODS: Analysis and integration of data regarding the blue light hazard and blue-blocking filters in ophthalmology and related disciplines. RESULTS: Large epidemiologic studies show that blue-blocking intraocular lenses (IOLs) do not decrease AMD risk or progression. Blue-filtering lenses cannot reduce disability glare because image and glare illumination are decreased in the same proportion. Blue light essential for optimal rod and retinal ganglion photoreception is decreased by progressive age-related crystalline lens yellowing, pupillary miosis, and rod and retinal ganglion photoreceptor degeneration. Healthful daily environmental blue light exposure decreases in older adults, especially women. Blue light is important in dim environments where inadequate illumination increases risk of falls and associated morbidities. CONCLUSIONS: The blue light hazard is misused as a marketing stratagem to alarm people into using spectacles and IOLs that restrict blue light. Blue light loss is permanent for pseudophakes with blue-blocking IOLs. Blue light hazard misrepresentation flourishes despite absence of proof that environmental light exposure or cataract surgery causes AMD or that IOL chromophores provide clinical protection. Blue-filtering chromophores suppress blue light critical for good mental and physical health and for optimal scotopic and mesopic vision.

NONCONFOCAL ULTRA-WIDEFIELD SCANNING LASER OPHTHALMOSCOPY: Polarization Artifacts and Diabetic Macular Edema.

PURPOSE: Bowtie-shaped polarization artifacts are often present in nonconfocal ultra-widefield scanning laser ophthalmoscope (SLO) images. We studied these artifacts and evaluated their potential value as clinical biomarkers in screening for center-involving diabetic macular edema (DME). METHODS: We performed a retrospective, observational, cohort study on 78 diabetic adult patients (143 eyes) who had spectral domain optical coherence tomography and nonmydriatic nonconfocal ultra-widefield SLO testing on the same day. Scanning laser ophthalmoscope green-only (532 nm), red-only (635 nm), and composite pseudocolor (532 plus 635 nm) images were examined for the presence of a foveal bowtie polarization artifact. RESULTS: Polarization artifacts were absent in all but one eye with center-involving DME (32 of 33 eyes). Polarization artifacts were also absent in many eyes without center-involving DME (49 of 110 eyes in pseudocolor images). As clinical biomarkers of center-involving DME, artifact absence has high specificity (99, 100, and 98% for green, red, and pseudocolor images, respectively) but poor sensitivity (49, 31, and 40% for green, red, and pseudocolor images, respectively). CONCLUSION: Foveal bowtie-shaped polarization artifacts occur routinely in nonconfocal ultra-widefield SLO images. Their presence indicates preserved foveal Henle fiber layer structure. Contemporary nonconfocal ultra-widefield SLO images lack the sensitivity for their bowtie artifacts to serve as reliable biomarkers in screening for center-involving DME.

Endoscopic vitreoretinal surgery: principles, applications and new directions.

PURPOSE: To analyze endoscopic vitreoretinal surgery principles, applications, challenges and potential technological advances. BACKGROUND: Microendoscopic imaging permits vitreoretinal surgery for tissues that are not visible using operating microscopy ophthalmoscopy. Evolving instrumentation may overcome some limitations of current endoscopic technology. ANALYSIS: Transfer of the fine detail in endoscopic vitreoretinal images to extraocular video cameras is constrained currently by the caliber limitations of intraocular probes in ophthalmic surgery. Gradient index and Hopkins rod lenses provide high resolution ophthalmoscopy but restrict surgical manipulation. Fiberoptic coherent image guides offer surgical maneuverability but reduce imaging resolution. Coaxial endoscopic illumination can highlight delicate vitreoretinal structures difficult to image in chandelier or endoilluminator diffuse, side-scattered lighting. Microendoscopy's ultra-high magnification video monitor images can reveal microscopic tissue details blurred partly by ocular media aberrations in contemporary surgical microscope ophthalmoscopy, thereby providing a lower resolution, invasive alternative to confocal fundus imaging. Endoscopic surgery is particularly useful when ocular media opacities or small pupils restrict or prevent transpupillary ophthalmoscopy. It has a growing spectrum of surgical uses that include the management of proliferative vitreoretinopathy and epiretinal membranes as well as the implantation of posterior chamber intraocular lenses and electrode arrays for intraretinal stimulation in retinitis pigmentosa. Microendoscopy's range of applications will continue to grow with technological developments that include video microchip sensors, stereoscopic visualization, chromovitrectomy, digital image enhancement and operating room heads-up displays. CONCLUSION: Microendoscopy is a robust platform for vitreoretinal surgery. Continuing clinical and technological innovation will help integrate it into the modern ophthalmic operating room of interconnected surgical microscopy, microendoscopy, vitrectomy machine and heads-up display instrumentation.

Glare's causes, consequences, and clinical challenges after a century of ophthalmic study.

PURPOSE: To provide a multidisciplinary synthesis of scientific information on disability, discomfort, dazzling, and scotomatic (photostress) glare. DESIGN: Perspective. METHODS: Analysis and integration of relevant historical and contemporary publications on glare in ophthalmology, illumination engineering, neurology, and other relevant disciplines. RESULTS: Disability glare is caused by scattered intraocular light (straylight) not useful for vision. Straylight casts a veiling luminance on the retina, reducing image contrast and impairing vision. In common environments, glare and target illumination sources have the same or similar spectra. Colored spectacle or intraocular lens filters reduce both proportionately, so they do not increase retinal image contrast or decrease disability glare. Discomfort glare is caused by situational illumination too intense or variable. Dazzling glare occurs when high illuminances are spread across the retina. Neurophysiological research is clarifying how discomfort and dazzling glare depend on different retinal photoreceptors and nociceptive brain pathways involving the trigeminal ganglion and thalamus. Photostress is caused by excessive local retinal photopigment bleaching uncommon in ordinary situations. Optical glare countermeasures are available for daytime driving but not oncoming automobile headlights at night. Filters that decrease daytime discomfort or dazzling glare also reduce nighttime mesopic and scotopic sensitivity. CONCLUSIONS: Glare is problematic for patients and clinicians despite a century of scientific research. Advances in understanding glare have been hampered by its complex, multidisciplinary nature and limited interdisciplinary communication. We provide one pathway through the forest of glare nomenclature and mechanisms. Improved diagnostic and therapeutic methodologies await continuing progress in understanding glare.

Concentric ring scanning laser ophthalmoscope artifacts and dysphotopsia in diffractive multifocal pseudophakia.

A 67-year-old woman had decreased visual acuity in her left eye and disturbing concentric ring dysphotopsias after bilateral implantation of ReSTOR (SN60D3; Alcon Laboratories, Inc., Fort Worth, TX) diffractive multifocal intraocular lenses (IOLs). Monochromatic (820-nm infrared and 488-nm red-free) scanning laser ophthalmoscopy (SLO) documented central retinal concentric ring patterns resembling the patient's drawings of her dysphotopsia, prompting investigation of the relationship of these phenomena. Similar SLO findings were present in four eyes of three additional ReSTOR pseudophakes without dysphotopsia, but absent in monofocal pseudophakes or phakic individuals. Optical analysis shows that concentric ring SLO imaging artifacts can be caused by coherent reflection of monochromatic laser radiation off the diffractive optical element on the IOL's anterior surface, whereas concentric ring dysphotopsias are due to diffraction or projection of broad spectrum light sources in ordinary environments. Thus, the IOL's diffractive optics is the origin of both concentric ring dysphotopsia and SLO artifacts, but diffraction or projection causes the visual phenomenon, whereas coherent reflection produces the imaging anomaly.

Ultraviolet-B phototoxicity and hypothetical photomelanomagenesis: intraocular and crystalline lens photoprotection.

PURPOSE: Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. DESIGN: Optical radiation measurement, analysis, and perspective. METHODS: Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. RESULTS: Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. CONCLUSIONS: If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs.

The role of environmental light in sleep and health: effects of ocular aging and cataract surgery.

Environmental illumination profoundly influences human health and well-being. Recently discovered photoreceptive retinal ganglion cells (pRGCs) are primary mediators of numerous circadian, neuroendocrine and neurobehavioral responses. pRGCs provide lighting information to diverse nonvisual (non-image-forming) brain centers including the suprachiasmatic nuclei (SCN) which serve as the body's master biological clock. The SCN exert functional control over circadian aspects of physiology. The timing and strength (amplitude) of SCN rhythmic signals are affected by light exposure. Light deficiency may attenuate SCN function and its control of physiological and hormonal rhythms which in turn can result in a cascade of adverse events. Inadequate pRGC photoreception cannot be perceived consciously, but may aggravate many common age-associated problems including insomnia, depression and impaired cognition. In this review we (1) summarize circadian physiology, emphasizing light's critical role as the most important geophysical timing cue in humans; (2) analyze evidence that typical residential lighting is insufficient for optimal pRGC requirements in youth and even more so with advancing age; (3) show how ocular aging and cataract surgery impact circadian photoreception; and (4) review some of the diverse morbidities associated with chronodisruption in general and those which may be caused by light deficiency in particular.

Blue-blocking IOLs decrease photoreception without providing significant photoprotection.

Violet and blue light are responsible for 45% of scotopic, 67% of melanopsin, 83% of human circadian (melatonin suppression) and 94% of S-cone photoreception in pseudophakic eyes (isoilluminance source). Yellow chromophores in blue-blocking intraocular lenses (IOLs) eliminate between 43 and 57% of violet and blue light between 400 and 500 nm, depending on their dioptric power. This restriction adversely affects pseudophakic photopic luminance contrast, photopic S-cone foveal threshold, mesopic contrast acuity, scotopic short-wavelength sensitivity and circadian photoreception. Yellow IOL chromophores provide no tangible clinical benefits in exchange for the photoreception losses they cause. They fail to decrease disability glare or improve contrast sensitivity. Most epidemiological evidence shows that environmental light exposure and cataract surgery are not significant risk factors for the progression of age-related macular degeneration (AMD). Thus, the use of blue-blocking IOLs is not evidence-based medicine. Most AMD occurs in phakic adults over 60 years of age, despite crystalline lens photoprotection far greater than that of blue-blocking IOLs. Therefore, if light does play some role in the pathogenesis of AMD, then 1) senescent crystalline lenses do not prevent it, so neither can blue-blocking IOLs that offer far less photoprotection, and 2) all pseudophakes should wear sunglasses in bright environments. Pseudophakes have the freedom to remove their sunglasses for optimal photoreception whenever they choose to do so, provided that they are not encumbered permanently by yellow IOL chromophores. In essence, yellow chromophores are placebos for prevention of AMD that permanently restrict a pseudophake's dim light and circadian photoreception at ages when they are needed most. If yellow IOLs had been the standard of care, then colorless UV-blocking IOLs could be advocated now as "premium" IOLs because they offer dim light and circadian photoreception roughly 15-20 years more youthful than blue-blocking IOLs.