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Silicon oil⁣

● Intraocular tamponade to maintain adhesion between RPE and neurosensory retina⁣

● Hydrophobic, specific gravity (0.97) less than water, refractive index (1.4) higher than⁣

vitreous⁣

● Repeating units of siloxane⁣

● Available in 1000/5000 centistokes⁣

Advantages:⁣

1. High surface tension⁣

2. Ease of removal⁣

3. Low toxicity⁣

4. Immiscible with water⁣




Immiscibility + High surface tension + Low SG = Tamponade effect on superior retina⁣

Preferable to use it when high elevation travel/flight travel is planned Difficulty in maintaining prone positioning⁣

Disadvantages:⁣

● Surface tension less than gas/saline- can pass through retinal breaks under traction more easily than gas⁣

● Hydrophobic - does not have desired retinal contact⁣

● Low SG- tamponade of inferior retina is difficult⁣

● Refractive index needs optical adjustments⁣

● Post-operative cataract formation⁣

● Emulsified SO can adhere to IOL⁣

● Secondary glaucoma⁣

● Corneal decompensation⁣


Indications:⁣


1. RD with PVR- prevents vasoproliferative factor migration, decrease post op hemorrhage⁣

2. Severe PDR- Diabetic TRD⁣

3. Macular hole⁣

4. Giant retinal tears- unfolding the retina⁣

5. Traumatic RD - long term tamponade⁣

6. Those who want to travel by air/ cannot maintain prone positioning⁣

7. Chronic uveitis with profound hypotony⁣

8. Infectious retinitis⁣

⁣9. Endophthalmitis- antibacterial properties ⁣

Complications:⁣

1. Emulsification⁣

2. Cataract⁣

3. Secondary glaucoma⁣

4. Band shaped keratopathy⁣

5. Corneal decompensation⁣

6. Recurrent retinal detachment⁣

7. Absorption of SO by silicon intraocular lenses⁣

8. Migration of silicon oil into optic nerve and brain


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‘Ocular curiosities!’⁣

Vitreous Cysts⁣

Tansley, 1899 - irregular spherical cyst that showed lines of pigment on its surface⁣

Congenital Cysts⁣

Remnants of the hyaloid vascular system⁣

Located at hyaloid canal & found in conjunction with Mittendorf's dot or⁣

Bergmeister's papillae⁣

Stable, do not progress and rarely interfere with vision⁣

Non-pigmented pearl-gray cysts with a smooth surface, sessile or pedunculated⁣

Located anterior to optic disc⁣

Can be limited in movement due to vitreous strands attaching cyst to optic⁣

disc⁣

Acquired Cysts⁣

Ocular trauma⁣

Intraocular inflammation/infection/ uveitis eg. Intermediate Uveitis, Toxoplasmosis⁣

Retinal diseases such as Retinitis pigmentosa, Choroidal atrophy, Retinoschisis, High myopia with uveal coloboma etc⁣

Retinal detachment surgeries⁣

Usually symptomatic -reduced vision⁣




Types⁣

Pigmented⁣

From pigment epithelium of iris or ciliary body later become detached into the vitreous, Brown colour⁣

Non-Pigmented⁣

From hyaloidal vascular system⁣

Translucent, mobile, yellow-gray⁣

HPE⁣

Congenital cysts are choristomas of primary hyaloidal system⁣

Derived from pigment epithelium of iris or ciliary body⁣

Contains immature melanosomes⁣

Pathophysiology of Acquired Cysts⁣

Trauma can cause damage to pigment epithelium of ciliary body and create pigment cysts⁣

Other theories: Vitreous reaction to underlying retinal degeneration can causes cysts, Ciliary adenoma breaking into the vitreous, cystic growths that occur at site of coloboma that enter the vitreous⁣

DD:⁣

Pigmented cysts mimic pigmented ocular tumors such as malignant melanoma Nonpigmented cysts mimic parasitic cysts such as Cysticercosis, Echinococcus etc.⁣

Ocular Investigations:⁣

B Scan to look for scolex in case of cysticercosis⁣

OCT - characterize the cyst⁣

UBM - rule out anomalies of ciliary body or posterior iris⁣

FFA - characterization of intra and extra cystic vascularisation ⁣

Management⁣

Asymptomatic cysts⁣

Observation and follow-up ⁣

Symptomatic cysts⁣

Laser cystotomy by Argon laser/Nd:Yag laser⁣

Pars plana vitrectomy with cyst excision⁣


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Link to article: https://eyewiki.aao.org/Vitreous_Cysts⁣

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Epiretinal Membrane ⁣

An avascular fibrocellular membrane that proliferates on the inner surface of the⁣

retina and produces visual impairment⁣

Causes:⁣

Idiopathic ERMs is the most common presentation. ⁣

Secondary ERMs: retinal vascular diseases including diabetic retinopathy, retinal vein occlusion, ocular inflammatory disease, trauma, intraocular surgery, intraocular tumors, and retinal tear or detachment.⁣

Symptoms: Gradual painless loss of vision, Metamorphopsia, Micropsia⁣

Pathology: Fibrous proliferative membrane like structure consisting of cells interspersed with an extracellular matrix.⁣

Fundus examination: ⁣

Thin sheen like membrane to a thick opaque membrane, associated with vascular tortuosity, straightening and dragging of vessel toward the fovea. ⁣

Associated intraretinal hemorrhage, cystic changes in macula, cotton wool spots, macular edema, macular hole or pseudohole. ⁣




Gass classification of ERM :⁣

Grade 0 – Cellophane maculopathy⁣

● Completely translucent membrane barely visible clinically. There is no foveal distortion and retinal traction ⁣

Grade 1 – Crippled cellophane maculopathy⁣

● Contraction of ERM⁣

● Membrane causes an irregular wrinkling of inner retinal surface.⁣

● If wrinkling is severe enough, para macular vessels may be pulled towards the fovea⁣

in a corkscrew formation (seen on FFA) ⁣

Grade 2 – Macular pucker⁣

● Membrane is thick and opaque.⁣

● Full thickness puckering of macula may be present along with edema, small⁣

hemorrhages, cotton wool spots and sometimes localized RD⁣

● Severe visual loss⁣

Cause of vision loss in ERM:⁣

● Contraction of ERM causes elevation of macula⁣

● Retinal distortion and traction⁣

● Macular edema⁣

Investigations :⁣

● Amsler grid⁣

● FFA - can show retinal vascular tortuosity, straightening and leakage, as well as⁣

CME, also helps in excluding the other retinal pathologies that may cause ERM formation ⁣

● OCT- To see CME,VMT,Localizing the edge and thickest part of ERM and to⁣

differentiate lamellar macular hole from pseudohole⁣

● Multifocal ERG⁣

Management :⁣

● ERM removal with/without ILM peeling


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