Retina

Retinopathy of Prematurity (ROP)

(ROP) is a potentially blinding disease caused by abnormal development of retinal blood vessels in premature infants. The retina is the inner layer of the eye that receives light and turns it into visual messages that are sent to the brain. With ROP, unwanted blood vessels grow on the baby's retina. These blood vessels can cause serious eye and vision problems later. Symptoms/presentation: ROP can go away on its own as an infant grows. If it does not go away, however, it needs to be treated. Otherwise, the child can have severe vision loss, or even go blind. ROP is described by its location in the eye (the zone), by the severity of the disease (the stage) and by the appearance of the retinal vessels (plus disease). The first stage of ROP is a demarcation line that separates normal from premature retina. Stage 2 is a ridge which has height and width. Stage 3 is the growth of fragile new abnormal blood vessels. As ROP progresses the blood vessels may engorge and become tortuous (plus disease).

Retinitis Pigmentosa

(RP) is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina. Forms of RP and related diseases include Usher syndrome, Leber congenital amaurosis, and Bardet-Biedl syndrome, among others. Symptoms: People with retinitis pigmentosa lose their vision slowly over time. Usually, though, they will not become totally blind. Symptoms depend on whether rods or cones are initially involved. In most forms of RP, rods are affected first. Because rods are concentrated in the outer portions of the retina and are activated by dim light, their degeneration affects peripheral and night vision. Vision becomes more constricted over time. If and when the disease progresses and cones become affected, visual acuity, color perception, and central vision are diminished. -Night blindness is one of the earliest and most frequent symptoms of RP. People with mainly cone degeneration, however, first experience decreased central vision and reduced ability to discriminate colors and perceive details. -RP is typically diagnosed in children, adolescents and young adults. It is a progressive disorder. The rate of progression and degree of visual loss varies from person to person. Many people with RP are legally blind by age 40, with a central visual field of less than 20 degrees in diameter.

55 year old patient presents with blurred and distorted central vision (like door frames appear skewed), the change in vision has happened gradually over 2-3 months, seems to be slightly worse, grey and black spots in central vision in right eye only. What are some Retina conditions that could present with the above symptoms?

- Macular hole: A break or hole in the macula usually affects those aged 60 and over, and can cause blurred and distorted central vision. Macular holes usually develop over time, so you may not notice any symptoms until your vision is affected. Early signs include blurring and distortion of your vision, and you may notice straight lines (such as window frames, telegraph poles or lines of text) appearing bent or wavy. - Macular Degeneration: Dry macular degeneration is a common eye disorder among people over 50. It causes blurred or reduced central vision, due to thinning of the macula. Dry macular degeneration may first develop in one eye and then affect both. Symptoms: Visual distortions, such as straight lines seeming bent Reduced central vision in one or both eyes The need for brighter light when reading or doing close work. Increased difficulty adapting to low light levels, such as when entering a dimly lit restaurant Increased blurriness of printed words Decreased intensity or brightness of colors Difficulty recognizing faces -Vitreomacular Traction (VMT): There are instances where a PVD is incomplete, leaving the vitreous partially attached to the retina, and causing tractional (pulling) forces that can cause anatomical damage. The resulting condition is called vitreomacular traction (VMT) syndrome. Symptoms: Decreased sharpness of vision Photopsia, when a person sees flashes of light in the eye. Micropsia, when objects appear smaller than their actual size. Metamorphopsia, when vision is distorted to make a grid of straight lines appear wavy or blank. -Epiretinal Membrane (Macular Pucker): also commonly known as cellophane maculopathy, are avascular (having few or no blood vessels), semitranslucent, fibrocellular membranes that form on the inner surface of the retina. They most commonly cause minimal symptoms and can be simply observed, but in some cases they can result in painless loss of vision and metamorphopsia (visual distortion). Symptoms: Patients may notice metamorphopsia, a symptom that causes visual distortion in which shapes that are normally straight, like window blinds or a door frame, looking "wavy" or "crooked," especially when compared to the other eye. In advanced cases, this can lead to severely decreased vision. Less commonly, ERMs may also be associated with double vision, light sensitivity or images looking larger or smaller than they actually are.

Layers of the Retina

-Choroidal Stroma -Choricocapillaris -Bruch's Membrane -Pigment epithelium -Photoreceptor Lm ayer (rods and cones) -External Limiting Membrane -Outer Nuclear Layer -Outer Pleixform Layer -Inner Nuclear Layer -Inner Plexiform Layer -Ganglion Cell Layer -Retinal Nerve Fiber Layer -Internal Limiting Membrane

Retina portion of the Visual Pathway

-Light stimulates the rods and cones in the Photoreceptor layer, electric (nerve) impulses are generated in these cells and relayed to the bipolar cells. -The nerve impulses then pass to ganglion cells . -the ganglion cells posses long fiber like axons, the axons from the ganglion cells form the optic nerve.

55 year old patient presents with blurred and distorted central vision (like door frames appear skewed), the change in vision has happened gradually over 2-3 months, seems to be slightly worse, grey and black spots in central vision in right eye only. Patient is scheduled for a routine dilated visit with no testing ordered, what testing would you elect to perform on this patient?

-Mac OCT -Amsler Grid -Fundus photo

Rods and Cones

-Two types of phooreceptor cells in the Photoreceptor layer of the retina. -Rods: Largely responsible for vision in reduced light ("night vision") and for periphreal vision. -Cones: Provide sharp central vision and the preception of color.

Central Retinal Artery Occlusion (CRAO)

A condition in which the blood supply to the retina is blocked because of a clot or embolus in the central retinal artery or one of its branches. The condition may be preceded by episodes of vision loss known as amaurosis fugax . The cause of CRAO is most commonly a clot or embolus from the neck (carotid) artery or the heart. This clot blocks blood flow to the retina. CRAO is considered a "stroke" of the eye. Studies show that about two-thirds of patients have underlying high blood pressure and one-fourth of patients will have significant carotid artery disease (plaque with narrowing of the artery lining), cardiac valvular disease or diabetes. Symptoms: Central retinal artery occlusion usually occurs with sudden, profound, but painless vision loss in one eye. Most people with CRAO can barely count fingers in front of their face or see light from the affected eye.

Central Retinal Vein Occlusion (CRVO)

A thrombus in a central retinal vein just where it enters the eye. Central retinal vein occlusion (CRVO) causes sudden, painless vision loss that can be mild to severe. Most people will have high blood pressure, chronic open-angle glaucoma and/or significant hardening of the arteries. Two basic classes of CRVO are: Ischemic: poor blood flow and accompanying poor vision. Non-ischemic: much better vision when you are first seen and fewer clinical findings.

What is Macular edema and what can cause it?

Macular Edema: happens when fluid builds up in the macula, causing swelling. Causes: -Diabetes. With diabetes, high blood sugar levels damage blood vessels, which leak into the macula. -Age-related macular degeneration (AMD). With AMD, abnormal blood vessels leak fluid and cause macular swelling. -Macular pucker/vitreomacular traction. When vitreous in the aging eye doesn't detach completely from the macula, the vitreous tugs on the macula or forms scar tissue, and pockets of fluid collect underneath it. -Retinal vein occlusion (RVO). With blood vessel diseases like RVO, veins in the retina become blocked. Blood and fluid then leak out into the macula. -Hereditary/genetic disorders (passed from parent to child), such as retinoschisis or retinitis pigmentosa. -Inflammatory eye diseases. Conditions like uveitis, where the body attacks its own tissues, can damage retinal blood vessels and cause swelling of the macula. -Medication. Certain drugs have side effects that can lead to macular edema. -Eye tumors. Both benign and malignant tumors can lead to macular edema. -Eye surgery. It's not common, but sometimes after glaucoma, retinal or cataract surgery, you can get macular edema. -Injuries. Trauma to the eye.

Pseudohole in the macula vs. lamellar hole

Macular hole: A true hole in the retina. This means that layers of the retina are absent. You can read more about macular hole at Surviving Recovery from Macular Hole Surgery. Macular pseudohole: Not a true hole; rather it is a condition in which scar tissue called epiretinal membrane tugs or pulls on the underlying retina, which can look similar to a macular hole during a clinical eye examination. However, a detailed examination, as well as more advanced imaging, such as optical coherence tomography (OCT), demonstrates that there is, in fact, no hole and no missing retinal layers. Symptoms: Macular hole: Blurring and distortion Macular pseudohole: Blurring and distortion, but to a lesser degree than with a macular hole

Torpedo Maculopathy

Torpedo maculopathy (TM)/ solitary hypopigmented nevus of the retinal pigment epithelium (RPE)/ paramacular albinotic spot syndrome/ congenital hypomelanotic freckle/ atypical macular coloboma was first described by Roseman and Gass in 1992, as a rare congenital anomaly of the RPE that produces a disruption of outer retinal layers. athogenesis remains unknown and the typical lesion is a single hypopigmented area in the macula, asymptomatic, temporal to fovea and with a characteristic torpedo-shape. Symptoms/presentation: On exam, visual acuity is not generally affected considering there is no foveal involvement, so that it is usually considered an incidentaloma. Nevertheless, central scotoma or microscotoma can be present at diagnosis. About the lesion, it is mostly unilateral, flat, asymptomatic and non-progressive, although bilateral, crescent and satellite wounds are also reported. Owing to the RPE and outer retina damage, these lesions are susceptible of CNV appearance and need to be close followed-up. There is a characteristic hypopigmented torpedo-shape area, temporal to macula, pointing to fovea with an hyperpigmented tail. The typical size is about two disc diameters horizontally by one disc diameter vertically, usually with foveal involvement.

Branch Retinal Artery Occlusion (BRAO)

Usually the cause is a clot or plaque (embolus) that breaks loose from the main artery in the neck (carotid) or from one of the valves or chambers in the heart. Symptoms: Patients present with an acute onset of painless monocular visual loss or visual field loss. More than 80 percent of people who have BRAO will recover visual acuity of 20/40 or better*, although most people will have noticeable and permanent vision problems such as blind spots or distortions.

Interpreting Macular OCTs

Watch this video for a thorough explanation of how to interpret an OCT. https://www.aao.org/annual-meeting-video/interpretation-of-oct

Wet Macular Degeneration

Wet macular degeneration is a chronic eye disorder that causes blurred vision or a blind spot in your visual field. It's generally caused by abnormal blood vessels that leak fluid or blood into the macula. Symptoms: Wet macular degeneration symptoms usually appear suddenly and worsen rapidly. They may include: -Visual distortions, such as straight lines seeming bent -Reduced central vision in one or both eyes -Decreased intensity or brightness of colors -A well-defined blurry spot or blind spot in your field of vision -A general haziness in your overall vision -Abrupt onset and rapid worsening of symptoms -Macular degeneration doesn't affect side (peripheral) vision, so it rarely causes total blindness. -Vision loss caused by abnormal blood vessel growth. Sometimes abnormal new blood vessels grow from the choroid under and into the macula (choroidal neovascularization). The choroid is the layer of blood vessels between the retina and the outer, firm coat of the eye (sclera). These abnormal blood vessels may leak fluid or blood, interfering with the retina's function. -Vision loss caused by fluid buildup in the back of the eye. When fluid leaks from the choroid, it can collect between the thin cell layer called the retinal pigment epithelium and the retina. This may cause a bump in the macula, resulting in vision loss or distortion. Treatment: Medications may help stop the growth of new blood vessels by blocking the effects of growth signals the body sends to generate new blood vessels. These drugs are considered the first line treatment for all stages of wet macular degeneration. Medications used to treat wet macular degeneration include: Bevacizumab (Avastin) Ranibizumab (Lucentis) Aflibercept (Eylea) -Photodynamic therapy. This procedure is sometimes used to treat abnormal blood vessels at the center of your macula. During photodynamic therapy, your doctor injects a drug called verteporfin (Visudyne) into a vein in your arm, which travels to blood vessels in your eye. Your doctor shines a focused light from a special laser to the abnormal blood vessels in your eye. This activates the drug, causing the abnormal blood vessels to close, which stops the leakage. Photodynamic therapy may improve your vision and reduce the rate of vision loss. You may need repeated treatments over time, as the treated blood vessels may reopen. After photodynamic therapy, you'll need to avoid direct sunlight and bright lights until the drug has cleared your body, which may take a few days. -Photocoagulation. During photocoagulation therapy, your doctor uses a high-energy laser beam to seal abnormal blood vessels under the macula. The laser causes scarring that can create a blind spot, but the procedure is used to stop the vessels from bleeding with the aim of minimizing further damage to the macula. Even with this treatment, blood vessels may regrow, requiring further treatment. Few people who have wet macular degeneration are candidates for this treatment. It generally isn't an option if you have abnormal blood vessels directly under the center of the macula. Also, the more damaged your macula is, the lower the likelihood of success. - Low vision rehabilitation. Age-related macular degeneration doesn't affect your side (peripheral) vision and usually doesn't cause total blindness. But it can reduce or eliminate your central vision — which is necessary for driving, reading and recognizing people's faces. It may be beneficial for you to work with a low vision rehabilitation specialist, an occupational therapist, your eye doctor and others trained in low vision rehabilitation. They can help you find ways to adapt to your changing vision.

Branch Retinal Vein Occlusion (BRVO)

When the vein is blocked, blood and fluid spills out into the retina. The macula can swell from this fluid, affecting your central vision. Eventually, without blood circulation, nerve cells in the eye can die and you can lose more vision. Symptoms: People who have a branch retinal vein occlusion near the retina may have decreased vision, peripheral vision loss, distorted vision or blind spots. A BRVO involves only one eye and usually develops in a person with high blood pressure or diabetes.