The Retinal Disorders 4/26/2017

The macula lutea, or yellow spot: Anatomic overview: The retina is a layer of neural tissue that represent the inner most lining of the eye ball. The macula lutea, or yellow spot: The conventional boundary of the macula, as defined histologically, is that area with 2 or more layers of ganglion cells, that is 5-6 mm in diameter and is centered vertically between the temporal vascular arcades. 4/26/2017

The central 1.5 mm within the macula is occupied by the fovea (or fovea centralis). Within the fovea is a central pit known as the foveola, a 0.35- mm-diameter region where the cones are slender and densely packed. Surrounding the fovea is a ring 0.5 mm in diameter, called the parafoveal area, where the ganglion cell layer, inner nuclear layer, and outer plexiform layer are thickest. Surrounding this zone, a ring approximately 1.5mm wide is termed the perifoveal zone. 4/26/2017

anterior, or peripheral, retina ora serrata equatorial retina anterior, or peripheral, retina ora serrata The retina histologically can be classified into :- a.retinal pigment epithelium b. neural retina. The layers of the neural retina can be seen easily in cross-sectional histologic preparations.The layers are listed in order from the outer to inner retina: 4/26/2017

1.rod and cone inner and outer segments 2.external limiting membrane 3.outer nuclear layer 4.outer plexiform layer 5.inner nuclear layer 6.inner plexiform layer 7.Ganglion cell layer 8.Nerve fiber layer (axons of the ganglion cells) 9.Internal limiting membrane. 4/26/2017

Retinal Detachment Separation of sensory retina from RPE (retinal pigment epithelium). RD classified as : 1. Rhegmatogenous 2. Non-Rhegmatogenous a.Tractiona b.Exudative 4/26/2017

Rhegmatogenous Retinal Detachment: Symotoms 1.Photopsia 2.Floaters 3.Visual field defects Signs 1.retinal break 2.lOP is usually lower 3.In recent retinal detachments convex configuration corrugated appearance undulates with eye movements 4/26/2017

Convex, deep mobile elevation Slightly opaque with dark blood vessels Slide 13 Retinal Break 4/26/2017

indirect binocular ophthalmoscope and Gohldman 3-mirror lens. Management: fundus exam with indirect binocular ophthalmoscope and Gohldman 3-mirror lens. 4/26/2017

2. Pneumatic retinopexy: 1. Scleral Buckling: 2. Pneumatic retinopexy: 4/26/2017

Tractional Retinal Detachment Symptoms Phtopsia (Nil) floaters(Nil) Visual field defect (evolve slowly) Signs Breaks are absent Detached retina has concave configuration. And Retinal mobility is reduced 4/26/2017

. Concave, shallow immobile elevation . Highest at sites of vitreoretinal traction Management: Pars plana vitrectomy 4/26/2017

Exudative Retinal Detachment . Convex, smooth elevation . May be very mobile and deep with shifting fluid Slide 8 4/26/2017

Age – Related Macular Degeneration 1. Atrophic (Dry, non exudative) Drusen and Geographic atrophy of the RPE 2.Exudative ( wet , neovascular ) Choroidal neovascular membrane (CNV) and eventual sub retinal scarring. Treatment 4/26/2017

Retinal Artery occlusion (RAO): Can be classified into: 1.Branch Retinal Artery occlusion most frequently caused by embolism 2.Central Retinal Artery occlusion most frequently the result of atherosclerosis 4/26/2017

Initially ocular massage, sublingual isosorbid dinitrate, and Treatment: It is an emergency, unless blood supply to the retina is restored on few hours at most, vision might be irreversibly lost. Initially ocular massage, sublingual isosorbid dinitrate, and intraocular pressure (IOP) reducing agents. 4/26/2017

Retinal Vein occlusion Can be classified into a. Branch retinal vein occlusion: hemorrhages, retinal edema, cotton-wool spots (nerve fiber layer infarcts) 4/26/2017

b.Central retinal vein occlusion is either 1. Non-ischemic which is commoner (75%) and milder. 2. Ischemic which is less common and more sever. 4/26/2017

Retinopathy of prematurity (ROP) Is a proliferative retinopathy affecting preterm infants of low birth weight who have often exposed to high ambient oxygen concentration. Screening: .Babies born at 31 wk’s of gestational age or less .birth weight of 1500 gm or less 4/26/2017

Hereditary Fundus Dystrophies 1. Retinitis Pigmentosa(RP): Diffuse retinal dystrophy ,predominantly affect the rod system. prevalence is 1:5000. Inheritance: sporadic disease AD (best prognosis), AR (intermediate prognosis), XL ( least common and most sever). Clinical features: nyctalopia (night blindness) during the third decade of life but may be sooner depending on the pedigree. 4/26/2017

Sugns: Rx: the classic triad of RP is 1.arteriolar attenuation 2.Waxy disc pallor 3.retinal bone spicule pigmentation. Rx: Daily administration of Vitamin A if instituted early may retard its progression. Prognosis is poor, On the long term 4/26/2017

2.Albinism: A genetically determined heterogenous group of disorders involving hypopigmentation of the eyes and/or the skin due to deficiency of tyrosinase which mediate conversion of tyrosine to melanin . the tow types are: OculocutaneousAlbinism: is an (AR) 2.Ocular Albinism: Is and (XL) 4/26/2017

Retinal Tumors .Is the most common intraocular malignancy of childhood Retinoblastoma: .Is the most common intraocular malignancy of childhood .It occur in about 1:20000 live births and account for about 3% of all childhood cancers. .the predisposing gen is at 13q14 .It could be : 1. Heritable: account for 40% of cases. 2.Non heritable account for 60% of cases. 4/26/2017

Presentation: .The vast majority present in the first 2 years of life. . Bilateral cases tend to present earlier than unilateral cases. 4/26/2017

Presentations of retinoblastoma Leukocoria - 60% Secondary glaucoma Strabismus - 20% 4/26/2017 Anterior segment invasion Orbital inflammation Orbital invasion

Investigations: Include 1. Ultrasound mainly used to assess the tumor size and detection of calcifications within the tumors. 2.CT scanning demonstrate gross involvement of the optic nerve,orbit and CNS. 3.MRI superior to CT scanning for optic nerve involvement and detection of pinealoblastoma which may coexist. 4.Systemic investigations e.g lumber puncture and bone marrow aspiration in special cases. 4/26/2017

Large tumor: chemotherapy or enucleation Treatment Depend on the tumor size, location and presence of vitreous seeds and also the state of the fellow eye. Small tumor with no seedings: transpupillary thermotherapy, laser, or cryotherapy Large tumor: chemotherapy or enucleation More aggressive treatment options may be attempted for larger or more widely spread tumor 4/26/2017

Differential diagnosis of leukocoria The term mean “white pupil”, depending on the lesion the pupil may appear normal in room light but have no light reflex on ophthalmoscope. 1. Retinoblastoma 2. Persistent hyperplastic primary vitreous 3. Retinopathy of prematurity. 4. Cataract. 5. Coat’s disease 6. Chorioretinal coloboma 7. Uveitis 8. Toxocariasis 9. Vitreous hemorrhage 10. Retinal dysplasia 11. Other tumors e.g. hamartoma and chroidal haemangioma 4/26/2017

Persistent hyperplastic Inflammatory cyclitic Posterior pole toxocara Differential diagnosis of leukocoria Persistent hyperplastic primary vitreous Inflammatory cyclitic membrane Congenital cataract Unilateral or bilateral Unilateral Unilateral or bilateral Coats disease Posterior pole toxocara granuloma Advanced retinopathy of prematurity Unilateral Always bilateral but may be asymmetrical Unilateral 4/26/2017