Post- Penetrating Keratoplasty Glaucoma

Transcription

1 Glaucoma Post- Penetrating Keratoplasty Glaucoma MBBS Mainak Bhattacharyya MBBS, Neha Rathie MBBS, Ritu Arora MD, DNB, Parul Jain MS, FICO Guru Nanak Eye Centre, New Delhi I association between penetrating keratoplasty (PK) and glaucoma 1. Post-penetrating keratoplasty glaucoma (PPKG) is one of the most challenging problems because of its irreversible visual loss due to damage to optic nerve as well Definition any time during the post operative period. Magnitude of the problem Rise in IOP following keratoplasty has been reported to be a biphasic phenomenon. The incidence of glaucoma after keratoplasty varies from 9% to 31% in the early postoperative and 18% to 42% in the late postoperative period 2. Full thickness keratoplasty vs. lamellar keratoplasty Since there is no disruption of Descemet s membrane in be no distortion of the anterior chamber angle, which is the stromal bed left behind the Descemet s membrane should theoretically be protective against drainage angle distortion. Although it is associated with a lower incidence (0-18%). Mechanisms of glaucoma 6 Early postoperative period synechiae (Figure 1) 3-5 Pre-operative Intra-operative Post-operative Adherent leukoma Bullous keratopathy Trauma Perforated corneal ulcer Mesodermal dysgenesis thickness smaller than host) development of PAS or severe intraocular www. dosonline.org l 51

2 Figure 1: Slit lamp photograph showing PAS post keratoplasty Figure 2: Gonioscopic view showing PAS in a case of post PK glaucoma (source: Dada T et al, Post penetrating keratoplasty glaucoma. Indian J Ophthalmol 2008) 8 etiology Zimmerman et al proposed that mechanical collapse of the trabecular meshwork in aphakic grafts is responsible for the higher incidence of secondary glaucoma 7. They postulated that ciliary body-lens support system lends posterior afforded by the Descemet s membrane. In aphakia, the posterior support is relaxed with the removal of the lens while anterior support is relaxed post PK after Descemet s excision which leads to a partial trabecular collapse and Late postoperative period Diagnosis IOP measurements surface is irregular, IOP can measured using if the graft surface is smooth with an intact epithelium. to inaccurately low readings, whereas corneal scarring will cause falsely high recording. Optic disc evaluation detect any progression of glaucomatous optic neuropathy. Visual field testing especially in the early postoperative period. Gonioscopy Provides assessment of peripheral anterior synechiae in the post operative period but is impossible in case of a failed graft where corneal edema precludes the visualization of anterior segment structures 8 (Figure 2). Ultrasound biomicroscopy (UBM) Used to assess the angle and establish the cause for post- PK glaucoma, especially in eyes with a failed graft where anterior segment details are not clearly visible. The extent of irido-corneal adhesions, phakic/aphakic status, location angle width and corneal thickness can be determined using UBM. In a UBM study done in eyes with post keratoplasty glaucoma, UBM showed the actual site of synechiae, viz. peripheral anterior synechiae, synechiae at the graft host 52 l DOS Times - Vol. 20, No. 1 July, 2014

3 Figure 3: Lippincott, Williams and Wilkins, 2008) Figure 4: AS-OCT showing edge of graft and PAS synechiae and intraocular lens iris synechiae 9 (Figure 3). It was thus concluded that UBM, serves as a useful tool for anterior segment evaluation in such cases and can help drainage devices. Anterior segment OCT immersion for evaluation of the depth of the anterior chamber angle and the causes of secondary angle closure 10 (Figure 4). Management Preventive Measures Pre-existing glaucoma should be appropriately managed either medically or surgically anterior synechiae procedure wound leaks prevent pupillary block glaucoma Medical management post keratoplasty glaucoma. betaxolol) apraclonidine hydrochloride) carbachol) and travoprost) used in current practice, as they are not very effective closure caused by PAS and no longer recommended. risk of retinal detachment, particularly in aphakes. and brinzolamide) suppress carbonic anhydrase enzyme in the corneal endothelium and long-term www. dosonline.org l 53

4 Beta-Blockers SPK, corneal anesthesia, dry eyes. Alpha adrenergic drugs SPK, dry eyes, allergic reactions. Miotics Topical Carbonic anhydrase inhibitors Altered taste, permanent graft failure in eyes with borderline endothelial counts. Systemic Carbonic anhydrase inhibitors Nausea, gastrointestinal disturbances, paresthesias, tinnitus, fatigue, depression, anorexia, weight loss, nephrolithiasis, and blood dyscrasias. Prostaglandin analogues Uveitis, cystoid macular edema in aphakia and pseudophakia and recurrent herpes simplex infection in patients with previous history of herpes. Benzalkonium chloride, the preservative in most topical glaucoma medications, is toxic to the corneal epithelium use can lead to graft decompensation especially in presence of borderline corneal endothelial status. Surgical Management Laser trabeculoplasty Argon laser trabeculoplasty Indications glaucoma medications. Recommended settings 50-μ spot size, 0.1-sec duration, and mw of power 11. Complications Post-operative IOP spikes and uveitis, which can trigger 12. trabeculoplasty may also be used. Laser iridotomy May be performed with an Nd:YAG (neodymium:yttriumaluminium-garnet) laser, if a pupillary block is suspected. Trabeculectomy surgery, extensive peripheral synechiae, aphakia, and extremely shallow anterior chamber days) and Mitomycin-C application ( mg surgery for glaucoma. mitomycin trabeculectomy in patients with post-pk glaucoma is 67-91% and that of graft failure is 12-18% 13. These agents appear to increase the success rate surgeries are less likely to be successful. formation (Figure 5). valve; Krupin implant) implant, Baerveldt implant). of the Ahmed glaucoma valve, is the ease of insertion and low incidence of hypotony in the immediate associated with a high incidence of increased IOPhypertensive phase (as much as 80%), 1-3 months after the procedure, which may need needling and area, such as the double-plate Molteno and Baerveldt implant, on the other hand, appear to exhibit a lesser incidence of the hypertensive phase and may achieve slightly lower IOPs in the long term. including corneal decompensation, appear to be similar among all GDDs l DOS Times - Vol. 20, No. 1 July, 2014

5 Figure 5: AGV in an eye with DALK (Source: Al-Mahmood AM et al. Glaucoma and corneal transplant procedures. J Ophthalmol 2012) 16 A high incidence of graft failure (average 36.2%) is associated with the use of GDD s. The drainage tube may provide a conduit for retrograde the risk of graft failure. might accelerate the process leading to graft failure. Cyclodestructive procedures advanced cases when medical or surgical interventions fail to control the IOP. production by destroying part of the ciliary body. using cryoprobe, Neodymium: Yttrium-Aluminium- Garnet (Nd:YAG) laser or a semiconductor diode respectively are the various options available. Complications include decrease in the Snellen visual acuity, graft failure, persistent hypotony, anterior uveitis, epithelial defects, severe pain, phthisis bulbi, hyphema, hypotony, intractable pain, sympathetic ophthalmia, scleral thinning, and vitreous hemorrhage. Transpupillary argon laser photocoagulation Another modality that describes use of Goldmann threemirror lens to ablate the ciliary processes one at a time. The laser is set at μm spot size for a duration of sec with a power of 1000 mw. Conclusion Post- penetrating keratoplasty glaucoma remains one of the leading causes of graft failure and visual loss. Knowledge of the risk factors such as preexisting glaucoma, aphakia and previous PK may help to limit the occurrence of glaucoma and to increase the chances of success of PK. Timely diagnosis of PPKG along with aggressive and timely management remains the cornerstone for preserving optimal graft clarity and visual function following keratoplasty procedures. References 1. Irvine AR. Kaufman HE. Intraocular pressure following penetrating keratoplasty. Am J Ophthalmol 1969;68: Foulks GN. Glaucoma associated with penetrating keratoplasty. Ophthalmology 1987;94: Ayyala RS. Penetrating keratoplasty and glaucoma. Surv Ophthalmol 2000;45: Sihota R, Sharma N, Panda A, Aggarwal HC, Singh R. Post penetrating keratoplasty glaucoma: Risk factors, management and visual outcome. Aust NZJ Ophthalmol 1998;26: Sharma A, Sharma S, Pandav SS, Mohan K. Post penetrating Indian J Ophthalmol May;62(5): Allingham R R, Damji K, Freedman S, Moroi S, Rhee D J. Shields textbook of glaucoma. 6th ed. 2011; p Zimmerman TJ, Krupin T, Grodzki W, et al: The effect of suture depth 1978;96: Dada T, Aggarwal A, Minudath KB, Vanathi M, et al. Postpenetrating keratoplasty glaucoma. Indian J Ophthalmol Jul- Aug;56(4): Dada T, Aggarwal A, Vanathi M, Gadia R, Panda A, Gupta V, et al. Ultrasound biomicroscopy in opaque grafts with post penetrating keratoplasty glaucoma. Cornea 2008; 27: Gupta P, Sharma A, Ichhpujani P. Post penetrating keratoplasty glaucoma- A review. Nepal J Ophthalmol. 2014;6(11): Van Meter WS, Allen RC, Waring GO 3d, et al: Laser trabeculoplasty for glaucoma in aphakic and pseudophakic eyes after penetrating keratoplasty. Arch Ophthalmol 1988;106: argon laser trabeculoplasty. Ophthalmology 1987;94: Ayyala RS, Pieroth L, Vinals AF. Comparison of mitomycin C trabeculectomy, glaucoma drainage device implantation and laser neodymium YAG cyclophotocoagulation in the management of intractable glaucoma after penetrating keratoplasty. Ophthalmology. 1998;105: Abdulla Al-Torbak. Graft survival glaucoma outcome after simultaneous penetrating keratoplasty and Ahmed glaucoma valve implant. Cornea 2003;22: Sidoti PA, Mosny AY, Ritterband DC, Seeder JA. Pars plana tube insertion of glaucoma drainage implants and penetrating keratoplasty in patients with coexisting glaucoma and corneal disease. Ophthalmology 2001;108: Ammar M. Al-Mahmood, Samar A. Al-Swailem, Deepak P. Edward. Glaucoma and corneal transplant procedures. J Ophthalmol : www. dosonline.org l 55