4ROLE OF NORMAL HEALTHY TRANSPARENT CORNEA Clear visualisation of retina; normal or diseased ( DO, I/O, Slit lamp Biomicroscopy)Investigations for diagnosis of retinal conditions ( FFA, ERG)Diagnosing complications of retinal conditions; neovascular glaucoma ( Gonioscopy)Easy & adequate treatment of retinal disorders (Laser or even Vitreoretinal Surgeries)
5CONDITIONS AFFECTING CORNEA & RETINA ( INDEPENDENT OF EACH OTHER) Congenital anomalies –Micro or megalocornea ; medullated nerve fibres in retinaDegenerations or Dystrophies –Lattice or Granular corneal dystrophies or Spheroidal degenerations ; Retinitis Pigmentosa or ARMD
6CORNEAL & RETINAL CONDITIONS LINKED BY VARIOUS FACTORS AgeARCUS SENILISAGE RELATED MACULAR DEGENERATION
20NUTRITIONAL DISORDERS VITAMIN A DEFICIENCYKeratomalaciaDegeneration of rod outer segmentsHYPERVITAMINOSISRaised intracranial pressure- Papillodema (A)Cystoid macular odema (B)Calcium deposits in cornea (D)
22CORNEAL CLOUDING IN HURLER SYNDROME (in all MPS except Hunter & Pigmentary retinopathy occurs in all Mucopoly-Saccharidoses except Morquio & Maroteaux LamyCORNEAL CLOUDING IN HURLER SYNDROME(in all MPS except Hunter &Sanfilippo)
23CORNEAL SURGERIES AFFECTING RETINA Refractive corneal surgeries ( leading to RRD, endophthalmitis)Penetrating keratoplasty ( leading to endophthamitis, RD)
24RRD FOLLOWING LASIK Is infrequent A study reported 0.05% incidence at mean of 24 mths after lasikOccurred 1 – 36 mths (mean 12.6 mths) after lasikOccurred in eyes with mean D of myopia before lasik
25If managed promptly, can result in good vision No cause effect relationship between lasik & RRD was provenHowever it is recommended that all pts scheduled for lasik undergo a thorough dilated fundus examination with scleral depression & also treatment of retinal lesions predisposing to RRD before the refractive surgery
26ENDOPHTHALMITIS FOLLOWING LASIK Incidence of sight threatening complications after lasik still remains low.Reports of endophthalmitis after incisional refractive surgeries – RK, hexagonal keratotomy, Ruiz procedure exist
28Causes Corneal stroma may come in contact with infectious agents from Patients own bodyContaminants present on instrumentsSurgeon or operating roomBreaks in epithelial barrier & excessive surgical manipulationPost op delayed epithelialisation of cornea, topical steroids, therapeutic CL’s, decreased corneal sensitivity & dry eye state
29ENDOPHTHALMITIS AFTER PKP Reported incidence of 0.2%, has decreased in the last decadeInfections developed within 72 hrs & in majority the donor rim culture grew the same organism as was obtained from the AC or vitreousBoth bacterial & fungalFungal enophthalmitis transmitted by K-sol stored corneasTorulopsis glabrata endophthalmitis after keratoplasty with organ cultured corneas
31RD FOLLOWING KERATOPLASTY FOR ANTERIOR SEGMENT TRAUMA 20 keratoplasties with or without anterior segment reconstruction carried out showed 80% clear graftsComplications –RD casesgraft rejection 2 casesglaucoma casesamblyopia caseretinal folds case
33CORNEAL ODEMA FROM IOP RISE AFTER RD SURGERY Scleral buckling procedures alter anatomical configuration of globe & affect rise in IOPFactors affecting IOP includeDegree of shortening of encirclageif SRF drainage done (2-3 mm)if SRF drainage not done (3-6mm)Tightness with which scleral fixation sutures are tied (1 tight suture raises IOP by 10mmHg immediately)
35CORNEAL ODEMA FROM GLAUCOMA AFTER VRS Erythroclastic glaucoma – secondary to inadequate removal of intraocular haemorrhageInflammatory glaucoma – trabeculitisExpanding gas bubble – mixing error (confusing cubic cm in syringe for %, pupillary block or unwise decision to use expanding gas in a total fill surgical situation)
36Emulsification glaucoma – uncommon delayed complication of silicone oil use Steroid glaucomaHyperoxygenation of vitreous cavity & secondarily acqueous humour occur after vitrectomy which is responsible for trabecular damage (Sanley Chang)
39EPITHELIAL BREAKDOWN IN LONG STANDING BAND KERATOPATHY
40VITREO- RETINAL SURGERIES Self retaining corneal contact lens system
41CORNEAL CONTACT LENS SYSTEM FOR VITREOUS SURGERY They neutralise the refractive power of corneaThey afford excellent visualisation of fundus, vitreoretinal pathologiesAllow corneal contact on rotation of globe & eliminate accumulation of blood or bubbles between lens & cornea
42CORNEAL OPACITIES – HINDRANCE IN RETINAL SURGERIES Cornea may become cloudy,opacified due to injury,infection orscar tissueScar tissue prevents light from passing through cornea resulting not only in vision loss but also in difficult visualisation &treatment of retinal(or other posterior segment) lesions.
43Epithelial scrapping done to improve visualisation Use of new ophthalmic microendoscopesEndoscopic laser photocoagulation of ischaemic retina against opacity of anterior eyeUse of temporary keratoprosthesis followed later by keratolpasty
45KERATOPROSTHESISPenetrating keratoplasty combined with vitrectomy using a temporary keratoprosthesis is a safe & effective method in treating severe ocular injury with blood stained cornea (or opacified corneas) & no light perception
47LASIK AFTER RD SURGERYMyopic refractive errors are common in eyes that develop RDMyopic changes may also be induced by RD surgeries because of changes in axial length, anterior chamber depth or position of the lensA study has shown improvement in UCVA in all eyes & no decline in BCVA in any of themNo retinal complication in post-op period although F/U is requiredOnly problem found was that of extensive conjunctival scarring which hampers the function of suction ring of microkeratome
50Corneal abrasion – which stains with fluorescein Acute corneal edema – due to focal or diffuse dysfunction of corneal endotheliummay be associated with folds in descemet membrane.Commotio retinae – gives grey appearance to fundus, frequently temporal occasionally may involve macula causing cherry red spot at fovea.Subsequent progressive pigmentary degeneration & macular hole formation may occur.Retinal breaks leading to RD may occur in the form of retinal dialysis, equatorial tears or macular holes.
54PENETRATING OCULAR TRAUMA Assault, domestic accidents, sports injuries may cause corneal lacerations with or without iris prolapse.Tractional RD may occur secondary to vitreous incarceration in the wound & intragel vitreous haemorrhage which stimulates fibroplastic proliferation. Subsequent contraction of membranes leads to tractional RD.
55CORNEAL WOUND WITH IRIS PROLAPSE PENETRATING INJURYCORNEAL WOUND WITH IRIS PROLAPSEVITREOUS PROLAPSE , INTRAOCULAR HAEMMORHAGE, TRD
56INTRAOCULAR FOREIGN BODIES May traumatize the eye mechanicallyIntroduce infection – endophthalmitis or panophthalmitisExert other toxic effects on intraocular structures depending on their typestone, organic FB’s – infectioniron, copper - sideosis, chalcosis respectivelyglass, plastics, gold, silver - inert
57CHALCOSISHigh copper content in FB – violent endophthalmitis like pictureLow copper content – chalcosis, picture similar to wilsons disease with Kayser Fleischer Ring in cornea & sunflower cataract.Retinal deposition results in golden plaques visible ophthalmoscopically.
59SYMPATHETIC OPHTHALMITIS Mutton fat keratic precipitates and multifocal choroiditis.
60RADIATION RETINOPATHY Trophic changes in eye can also occur after radiotherapy in the form of corneal epithelial breakdown.
61DRUGS AFFECTING CORNEA & RETINA Chloroquine & hydroxychloroquineVortex keratopathy – whorl like fine greyish to golden brown corneal epithelial deposits in form of arborizing horizontal lines resembling cats whiskers.Unlike retinopathy, it bears no relationship to dosage, duration or treatment.
63CHLOROQUINE MACULOPATHY Risk increases when cumulative dose exceeds 300g.(250 mg daily for 3 yrs)Loss of foveal reflexCentral foveal pigmentation surrounded by depigmented zone of RPE atrophy which is again surrounded by hyperpigmented ringBull’s eye macular lesionUnmasking of larger choroidal blood vessels & development of pigment clumps in retinal periphery.
64Tamoxifen crystalline maculopathy & vortex keratopathy Specific anti estrogen used in treatment of selected patients with breast carcinomaMultiple yellow crystalline ring like deposits at the maculaePersist on cessation of treatmentMaculopathy rare, routine screening not warranted
70ALPORTS SYNDROMERare abnormality of glomerular basement membrane caused by mutations in genes encoding particular forms of type 4 collagenYellow punctate flecks in premacular area sparing foveaLarger flecks become confluent in peripheryAssociated with anterior lenticonus & occasionally posterior polymorphous corneal dystrophy
71ALPORTS SYNDROME PERIPHERAL FLECKS IN RETINA POSTERIOR POLYMORPHOUS DYSTROPHY
72KERATOCONUS WITH RETINITIS PIGMENTOSA Non-infective,progressive, bilateral thinning of cornea with ectasia of conical shapeDirect ophthalmoscopy from a distance of 1 foot shows an oil droplet reflexRetinoscopy shows an irregular scissor reflexSlit lamp biomicroscopy shows very fine vertical deep stromal striae (vogt lines) which disappear with external pressure on the globe
74OIL DROPLET REFLEX IN KERATOCONUS ACUTE HYDROPS IN KERATOCONUS
75THUS, NO PART OF THE HUMAN EYE CAN BE STUDIED IN ISOLATION THE CORNEA & RETINA INFLUENCEEACH OTHER IN HEALTH , FUNCTION &DISEASETHE INFLUENCE OF ONE ON THEOTHER IS OF CLINICAL SIGNIFICANCETO THE PRACTISING CLINICIAN