retina disorder

* *

* * 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.
The retina is a layer of neural tissue that represent the inner most lining of the eye ball.


* * 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.

* * 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:

* * 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.

* * Retinal Detachment Separation of sensory retina from RPE (retinal pigment epithelium). RD classified as : 1. Rhegmatogenous

2. Non-Rhegmatogenous a.Tractiona b.Exudative

* * 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

* * Retinal Break

Convex, deep mobile elevation

Slightly opaque with dark blood vessels Slide 13

* * Management: fundus exam with indirect binocular ophthalmoscope and Gohldman 3-mirror lens.

* * 1. Scleral Buckling:

2. Pneumatic retinopexy:


* * 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

* * . Concave, shallow immobile elevation . Highest at sites of vitreoretinal traction

Management: Pars plana vitrectomy



* * . Convex, smooth elevation . May be very mobile and deep with shifting fluid Slide 8
Exudative Retinal Detachment

* * Age – Related Macular Degeneration1. Atrophic (Dry, non exudative) Drusen and Geographic atrophy of the RPE2.Exudative ( wet , neovascular )Choroidal neovascular membrane (CNV) and eventual sub retinal scarring.Treatment

* * 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

* * 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.

* * Retinal Vein occlusion Can be classified into a. Branch retinal vein occlusion:

hemorrhages, retinal edema, cotton-wool spots (nerve fiber layer infarcts)

* * 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.

* * 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


* * 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.


* * Sugns: 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

* * 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)

* * Retinal Tumors 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.

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

* * Leukocoria - 60%

Strabismus - 20%
Secondary glaucoma
Anterior segment invasion
Orbital inflammation
Orbital invasion
Presentations of retinoblastoma



* * 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.

* * 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

* * Differential diagnosis of leukocoriaThe 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 coloboma7. Uveitis 8. Toxocariasis9. Vitreous hemorrhage 10. Retinal dysplasia11. Other tumors e.g. hamartoma and chroidal haemangioma

* * Differential diagnosis of leukocoria

Congenital cataract
Unilateral or bilateral
Unilateral
Inflammatory cyclitic membrane
Persistent hyperplastic primary vitreous
Unilateral or bilateral
Coats disease
Unilateral
Unilateral
Advanced retinopathy of prematurity
Posterior pole toxocara granuloma
Always bilateral but may be asymmetrical