Corneal edema after cataract surgery

seminar

1. Corneal edema after cataract surgery

2. Introduction Corneal edema is the swelling of the corneal stroma due to damage to corneal endothelium causing decreased visual acuity Endothelium continuously pumps fluid from cornea and keeps it dry and clear Resolves within few days or weeks after surgery

3. Pathophysiology Corneal endothelium is a hydrophobic barrier made up of a single layer of non regenerative cells Cataract surgery can injure endothelium Surviving cells change shape and grow larger to fill the spaces left by destroyed cells If lot of cells are damaged, corneal stroma is flooded by fluids causing edema

4. The excessive hydration interferes with normal spacing of proteins (type1 collagen fibrils) of the cornea If it progresses first stromal and then epithelial edema develops Epithelial edema is associated with bullae – bullous keratopathy

5. Pathophysiology Inadequate endothelial pump function ↑ IOP can compromise the endothelial pump Inflammation reduces the endothelial pump function

6. Causes preoperative : 1. Endothelial dystrophy – CHED FECD PPMD 2.PXF 3.Trauma to corneal endothelium Intraoperative : 1. Instrumentation 2. IOL 3. Irrigating solutions 4. excessive use of phaco power 5. Chemicals on instruments 6. DMD Postoperative : 1. Vitreous in AC 2. Direct endothelial touch 3. Flat AC 4. ↑IOP 5. Inflammation, retained cortex and visco

7. Cause contd … Direct injury to endothelium by instrument or IOL implant causes endothelial damage Diffuse edema – difficulty in nucleus delivery TASS – diffuse endothelial decompensation DM detachment

8. Loose ACIOL, loose pupillary supported iris plane IOL – directly traumatizes the endothelium Late onset corneal edema associated with ACIOLs is accompanied by CME – cornea retina syndrome ACIOL causes chronic subclinical inflammation Gonioscopy – PAS around closed loop haptics

9. Prevention Minimal instrumentation Careful IOL implantation Protect endothelium Maintain AC Prevent DM detachment Treat post op inflammation

10. Investigations Pachymetry : severity of corneal edema Specular microscopy : morphological analysis can be done in patients suspected with endothelial dystrophies AS-OCT : 1. Noncontact procedure, gives high resolution cross sectional images of ocular tissues 2. Area and size of DMD, corneal thickness and levels of scarring can be determined Confocal microscopy : 1. Corneal endothelial status in corneal edema 2. Layer by layer analysis

11. Treatment Eliminate the cause Treat inflammation Lower IOP Remove tissue IOL contact Reattach DM Enhance surface dehydration – hypertonic agents Restore anatomy : 1. DSEK 2. DSAEK 3. DMEK 4 . PKP

12. Hypertonic solutions : 5% sodium chloride eye drops or ointment – reduces the accumulation of edema Improves visual outcome Creates osmotic gradient via tear film outside the cornea that pulls fluid from cornea Anti inflammatory therapy : Transient dysfunction of endothelial pump Topical steroids - Prednisolone acetate 1% hrly and cycloplegics to keep the pupil mobile.

13. Descemet’s Detachment If DM is brought back in to anatomic apposition and if endothelium is not damaged, the pump function itself reattaches the DM because of relative vacuum created by endothelial pump Intracameral air bubble I ntracameral SF6 or C3F8 T ranscorneal suturing

14. Mackool and Holtz classification for Descemet membrane detachment was based on the length of detachment Planar - <1mm Non planar - >1mm Non planar DMD – treated surgically HELP algorithm : Based on AS-OCT

15. Fuchs dystrophy Soft shell technique – protects endothelium Pachymetry and specular microscopy Endothelial cell count <1000/mm and corneal thickness >640 microns – more corneal decompensation with intraocular surgery Cataract surgery combined with penetrating keratoplasty to be done

16. TASS : In acute phase - Topical corticosteroids Late phase – development of endothelial decompensation requires keratoplasty Penetrating keratoplasty – last resort in cases with corneal opacification Graft failure is common due to persistant anterior segment inflammation Endothelial keratoplasty has been reported to have good visual outcomes in cases of post‑TASS corneal decompensation

17. The time interval between TASS and DSAEK is a critical factor in determining long‑term success Minimum 3–6‑month waiting period after TASS is essential for optimal outcomes