glaucoma n cornea

GLAUCOMA&

CORNEA

Introduction

• Cornea PrimaryGlaucoma Secondary

• Glaucoma PrimaryCornea Secondary

CORNEA PRIMARYGLAUCOMA SECONDARY

Cornea PrimaryGlaucoma Secondary

• Developmental disorders

• Keratitis / Keratouveitis

• Dystrophies

• Trauma - Chemical Injury

• Post Keratoplasty

• Post LASIK

DEVELOPMENTAL DISORDERS

Developmental Disorders

• Peter’s anomaly

• Sclerocornea

• Aniridia

• Axenfeld-Rieger Syndrome

Peter’s anomaly

• Called anterior chamber cleavage syndrome

• Type I – normal lens

• Type II – abnormal lens

• Microphthalmos, myopia, aniridia, cataract

• Glaucoma occurs in 50% eyes

Axenfeld

• Anteriorly displaced and prominent Schwalbe’s line (posterior embryotoxon)

• 50% eyes develop glaucoma that occurs due to the anterior segment dysgenesis

Axenfeld

Reiger Anomaly

• Midperipheral iris adhesions to cornea

• Pupillary distortions

• Microcornea or macrocornea possible

KERATITIS / KERATOUVEITIS

Keratitis / keratouveitis

• Interstitial keratitis

– Mechanism is concomitant iridocyclitis, open angle and closed angle mechanisms

– Multiple iris cyst may form causing angle closure in a few cases


• Herpetic Keratouveitis

– 28% had IOP raised, 10% had glaucoma damage


• Zoster Keratouveitis

– Sectoral iris atrophy and mutton fat KPs

DYSTROPHIES

Dystrophies

• ICE Syn.

• PPMD

• Fuch’s Endo. Dys.

ICE syndrome

• Primarily a corneal endothelial disease

• A clinical spectrum of disease earlier thought to as distinct clinical entities

• Progressive iris atrophy

• Chandler syndrome (most common)

• Cogan Reese Syndrome

ICE syndrome

ICE syndrome

• Female predilection

• Reduced VA

• Pain

• Iris abnormalities

• Corneal edema

• Angle abnormalities

• Glaucoma

Progressive iris atrophy

• Corectopia, atrophy, Hole formation

• MC to cause glaucoma

Chandler Syndrome

• Typical corneal edema

Cogan Reese Syndrome

• Nodular pigmented iris lesions along with other features

Glaucoma in ICE

Glaucoma in ICECampbell’s Membrane theory

PPMD

• Blisters or vesicles at DM level

• Glaucoma caused due to

– iridocorneal adhesions (not related to severity)

– High insertion of uveal tissue

PPMD

• PAS varieties

– Without membrane

– With IT or IC apposition

– Bridging open TBM

• KP to be avoided until absolutely necessary as high chances of failure and recurrence

• Mx to include exam for renal dis., hearing loss and hernias

Fuch’s

• Reduced cell densities have been reported in association with ocular hypertension, angle-closure glaucoma, exfoliative glaucoma, and glaucomatocyclitic crisis

• ACG more a/w Fuch’s due to axial hyperopia and shallow ACs

Fuch’s

• Glaucoma incidence is less in Fuch’s

• Topical CAIs to be avoided

GLAUCOMA IN CHEMICAL BURNS

Glaucoma in Chemical Burns

• Complex pattern of IOP - Immediate rise then hypotony then late IOP elevation

• More common after alkali burns

• More accurate measurement with pneumatic or MacKay Marg

Glaucoma in Chemical Burns

• Stage wise mx

– Early rise

• due to scleral shrinkage and release of active substances

• Beta blockers, Alpha agonists, CAIs, Hyperosmotics

– Intermediate rise

• Due to inflammation

• Aqueous suppressants, cycloplegics and hyperosmotics, steroids

– Late rise

• Trabecular damage, PAS or intraocular scarring

• Standard medical or surgical rx

POST KERATOPLASTY

Post Keratoplasty

• Glaucoma is leading cause of irreversible vision loss post KP

• Important cause of graft failure

• Glaucoma patients have low endothelial counts already to begin with

– Both in open and closed angle

– More so in Pxf patients

Post PKP

• Post PK OHTN incidence is 5.5%-47.9%

• Higher ocular surface disease in glaucoma pts.

• Keeping donor corneal size 0.5mm larger does not seem to affect IOP

• Oversizing the graft is protective in aphakic eyes

Types

• Closed angle 59%

• Steroid induced 21%

• Open angle 11%

• Angle recession 3%

• Aqueous misdirection 3%

• Unknown 3%

Risk Factors

• Recipient age older than 60 years

• Aphakia

• Preexisting glaucoma (60%cf.15%)

• Adherent leukoma

• Bullous keratopathy

• Herpetic keratitis

• Trauma

• Keratoconus

• Associated vitrectomy (4x)

• Anterior segment reconstruction (4x)

• Repeated transplants

• Mechanism of Open angle glaucoma post KP is really elusive

• Steroid use – 11-35%

• Angle distortion

• Collapse of TBM

• Inflammation

• Retained OVD

• Vitreous prolapse in angle

Graft survival

• ~58% cf. ~80% in without glaucoma

• Increased rate of endothelial loss post sx

• Risk category as per indication of PK

– Low

• Keratoconus, stromal dystrophies

– Moderate

• Fuch’s and Herpetic infection

– High

• ABK/PBK, Trauma, ulcers, perf. and ICE

• Tonometry more reliable with McKay Marg, Tonopen, iCare cf. Goldmann or Perkin's

• For managing, Sihota et al report

– Med rx 51.9%

– Filter sx 29.1%

– Cyclodest. 19%

Medical rx

• Avg IOP reduction of 8.7mm Hg on switching patients to Cyclosporine A

• Topical dorzolamide may cause irreversible damage to endothelial cells

• Beta Blockers – surface changes, epithelial toxicity

Medical rx

• Pilocarpine – increases blood aqueous barrier permeability

• Latanoprost – ant uveitis, CME, herpetic flare up

• Alpha agonists – dry eye and allergic reactions

Surgical rx

• Success without MMC vs with MMC –25% to 73%

• No diff in IOP control or graft failure between Trab with MMC (76.5%), tube shunt (80%) or Cyclophotocoagulation (63.6%)

• Higher rate of rejection in surgical rx group

Surgical rx

• Higher rate of graft survival and good IOP control with combined trab and PK cf. Trab then followed by PK

• Higher graft survival for tube after PK cf. concurrent or prior to PK (3.8 to 4.7 times)

• Tube placement in AC or vitreous cavity comparable IOP control

Surgical Rx

• Laser trabeculoplasty is promising

• A reported success even after 150 degree PAS

Post DALK

• 0-17% incidence

• Acute elevation up to 36% patients

• All DALK patients could be managed with medical management alone in a study

With EK

• 0 to 15% cases

• Mechanisms

– pupillary block related to the air bubble

– obstruction of the trabecular meshwork resulting from long-term steroid use

– PAS formation

• Prior sx makes it more difficult in keeping complete AC gas fill to support EK, increased EK graft dislocation in perioperative period

With EK

• Post DSAEK

– 30-54% incidence

– Pre-existing glaucoma doubles the risk of Post DSAEK glaucoma exacerbation

– Twice the relative risk of rejection

– Concurrent gonio-synechiolysis is a risk factor

With EK

• Post DMEK

– 6.5–12.1%

• Laser PI is recommended prior to endothelial keratoplasty

• Some even prefer to do an inferior PI

• Air bubble ≤80% of AC volume is recommended

With Keratoprosthesis

• Incidence before pro implantation ranges 40-76%

• Post op incidence ~15%

• AS-OCT helpful to determine angle status post sx

• IOP measurement is very unreliable

• Most surgeons rely on digital palpation

With Keratoprosthesis

• Implantation of GDD at time of prosthesis sx is suggested

• Given uncertainty of absorption of topical medications with OOKP, systemic medications and surgery are generally preferred

Investigations post KP

• Corneal surface irregularities and astigmatism post sx limit the usefulness

• FDT has been shown to be independent of topographic changes

POST LASIK

Post LASIK

• PISK Pressure induced stromal keratitis

• Similar to DLK but with raised IOP

• Suspect when keratitis does not respond to or becomes worse even after escalating steroids

GLAUCOMA PRIMARYCORNEA SECONDARY

Glaucoma PrimaryCornea Secondary

• Pressure induced changes

• Exfoliation induced endothelial change

• Drug induced changes

PRESSURE INDUCED CHANGES

Cornea Properties and IOP

• Applanation tonometry is related to elasticity of the cornea

• Low Corneal Hysteresis is a/wglaucomatous VF damage and optic nerve defects

• CH may be strongly a/w glaucoma diagnosis, risk of progression and effectiveness of rx

Haab’s Striae

Acute ACG

Exfoliation Syndrome

Significantly lower than

normal cell density

Drug induced changes

• Mean CCT increased after Dorzolamide treatment

• In susceptible individuals, there may be clinically significant corneal edema

• Ocular surface abnormalities

Drug induced changes

• Timolol (BKC) a/w SPK & corneal anesthesia, OCP

• PG not to be used in post HS keratitis

References• Becker & Schaffer, 8th edition

• Shield’s, 6th edition

• Corneal Transplantation and glaucoma, Haddadin et al, Seminars in Ophthalmology, 2014;29(5-6):380-396

• Glaucoma following corneal replacement, Baltaziak et al, Survey Ophthalmology 2017

• Corneal properties and Glaucoma, Gaspar et al, Arq Bras Oftalmol.2017;80(3):202-6

glaucoma n cornea

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