![]() ![]() 3,5 Although this would not replace a retinal exam or photo, it has the potential for patients to train and screen themselves to identify early changes in many retinal diseases. 3 Studies suggest that this is an effective, noninvasive and portable screening tool to detect retinal dysfunction in diabetic retinopathy, allowing practitioners to identify asymptomatic patients prior to the onset of central vision loss. Scanning laser entoptic perimetry is of particular interest to assess diabetic retinopathy, a leading cause of blindness where early detection is a key factor in visual preservation. More recent studies recognize this modality as the method to measure entoptic phenomena, as it can offer significant retinal detail as it pertains to foveal capillary detail, the size of the foveal avascular zone (FAZ) and macular blood flow, with greater accuracy than more invasive methods, such as fluorescein angiography. 1 It was also helpful in cases where significant media opacities existed, where-if the illumination of a closed eye induced shadows-it correlated with good retinal and macular function. Screening ApplicationsIn the late 1990s, the application of this afterimage was used clinically to grossly measure potential acuity, as patients’ lack of perception of their vessels correlates highly with poor macular function and markedly reduced acuity. Here, entoptic phenomenon is perceived as vitreous floater secondary to posterior vitreous detachment. 2 In fact, it is this observation, which led to the conclusion that there must be a rapid mechanism of image creation and erasure as the foundation of normal visual processing. 1 It differs from a real image, particularly in that it does not track with eye or retinal movement due to the direct and constant relationship with the photoreceptor layer. HistoryEntoptic phenomena were first described by Johann Purkinje in the early 1800s, to describe the fleeting, black afterimage of retinal vasculature, later coined the ‘Purkinje tree.’ 1 This phenomena occurs due to the location and pattern of the branching retinal vascular ‘tree’ in front of the photoreceptor layer, casting a shadow that is only induced when the anterior segment of the eye is illuminated. This month, let’s evaluate what significance, if any, these reflections hold to us as eye care practitioners. 1,2 The presence or absence of different entoptic phenomena can raise red flags for posterior and anterior abnormalities, and even refractive and convergence conditions-making them potential markers of disease presence and progression. We should send him a kit.Oftentimes, when our patients are sitting behind the slit lamp during a routine examination, we hear them cry, “Wow, I can see the reflection of my blood vessels!” The image that appears to them is an instance of entoptic phenomena (EP), a phrase derived from the Greek words ‘inside’ and ‘light’ or ‘vision’, which describes the ability of an individual to perceive substances endogenous to their own eye, such as retinal vessels or vitreous opacities. He believes amblyopia is uncureable after a certain age. Tim Root has a popular vision science youtube channel. Rectus muscles: 4 big eye movement muscles, superior rectus, inferior rectus, lateral rectus, and medial rectus The annulus of Zin: Where the rectus muscles that move the eye meet. Ganglion Nerves: Larger nerves that transmit signals from the retina to the brain through the optic nerve. The focusing organ in the eye it's composed of a capsule, cortex, and nucleus.Ĭhoroid: Contains deep blood vessels that support the retina. Vitreous chamber: Holds the jelly-like filling of the eye called vitreous humorĬiliary body: Pulls on the lens to help the eye focus at different distances Sclera: The tough, connective tissue "white of the eye"Ĭornea: The clear window of the eye that has five layers. ![]() Orbicularis Oculi: The round muscle of the eyelids that forces the eyes to close (close hard - that's it!)Ĭranial Nerves of the Eye: CN2 transmits visual information from eye to brain, CN3 moves the eyes (4 of 6 muscles) and opens the eye, CN4 moves the eye (only the superior oblique muscle), CN5 adds sensation (mainly pain!), CN6 moves the eye (only the lateral rectus muscle), and CN7 closes the eye Tarsal plate: The tough, connective tissue plate inside your eyelids Limbus: Refers to the area of tissue surrounding the cornea which contains stem cells Ĭonjunctiva: Clear, vascular layer of tissue that protects the eye There is a great Optometry lecture series on Youtube.
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