SOOSAN JACOB, MS, FCRS,DNB ATHIYA AGARWAL, MD, DO; AMAR AGARWAL, MS, FRCS, FRCO

1. RELAXING DESCEMETOTOMY: A NEW SURGERY FOR TAUT DESCEMET’S MEMBRANE DETACHMENT &A NOVEL CLINICO-PATHOLOGICAL CLASSIFICATION OF DESCEMET'S MEMBRANE DETACHMENT SOOSAN JACOB, MS, FCRS,DNB ATHIYA AGARWAL, MD, DO; AMAR AGARWAL, MS, FRCS, FRCO GAURAV PRAKASH, MD DR. AGARWAL’S GROUP OF EYE HOSPITALS & EYE RESEARCH CENTRE, CHENNAI, INDIA NONE OF THE AUTHORS HAVE ANY FINANCIAL DISCLOSURES

2. PURPOSE • BACKGROUND :Relaxing retinotomy is used when retinal foreshortening does not allow retina to settle down unless relaxing retinotomies are made. A similar situation can arise in the cornea when there is traction on the Descemet’s Membrane (DM) secondary to inflammation or fibrosis or if the DM gets incarcerated in a wound or suture. This can lead to a Taut Descemet’s Membrane Detachment (TDMD) as opposed to a DM which is torn and detached from the overlying stroma such as seen following phacoemulsification. Injecting air or long acting gas into the anterior chamber (AC) in an eye with TDMD does not allow the DM to appose against the corneal stroma because of the foreshortening . Relaxing Descemetotomy based on a principle similar to relaxing retinotomy would be the solution in this scenario. • PURPOSE:TO DESCRIBE A NEW SURGICAL TECHNIQUE FOR TAUT DMD (TDMD) AND TO PROPOSE A NEW ETIO-CLINICO-PATHOLOGICAL CLASSIFICATION SCHEME FOR DMD VIZ. STRIPPED DSCEMET’S MEMBRANE DETACHMENT (SDMD) AND TDMD

3. METHODS IF THERE IS INADEQUATE APPOSITION AFTER AIR INJECTION, RELAXING DESCEMETOTOMY IS PROCEEDED WITH. • INTRA-OPERATIVE EVALUATION: • TRYPAN BLUE DYE IS INJECTED • ANTERIOR CHAMBER IS IRRIGATED WITH BALANCED SALT SOLUTION (BSS) TO WASH AWAY EXCESS TRYPAN BLUE AND TO STUDY THE DYNAMICS OF THE DETACHED DM • PRE-OPERATIVE EVALUATION: • PATIENTS WITH CORNEAL EDEMA AND DESCEMET’S MEMBRANE DETACHMENT (DMD) WERE STUDIED. • THOROUGH PRE-OPERATIVEEVALUATION WAS DONE • ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY (ASOCT) WAS DONE • EXTENT OF DETACHMENT AND THE DEGREE OF TAUTNESS ASSESSED Taut Descemet’s Membrane Detachment

4. SURGICAL TECHNIQUE • . AC is filled with BSS/air. Air aids visualization of edge of DM 26 gauge needle with tip bent in the reverse direction as capsulotomy needle Bent needle is introduced into the AC and relaxing Descemetotomy incisions are made

5. SURGICAL TECHNIQUE Descmetotomy continued till DM is fully apposed against stroma. Extent of incision is determined real time during surgery by assessing degree of residual foreshortening Non-expansile C3F8 (14%) or SF6 (12%) for post-operative tamponade Patient maintains a face up position for 1 hour.

6. 2 eyes of 2 patients underwent Relaxing Descemetotomy (RD) for TDMD. The patients tolerated the procedure well and neither required a repeat surgery. For both cases, the cornea became clearer post-operatively and the RDs could be seen on slit lamp imaging ASOCT showed an attached DM RESULTS

7. Case 1 • Iso-expansile concentration of SF6 (12%) injected into the AC with face up positioning for 1 hr. Two Relaxing Descemetotomy incisions were made while AC was filled with BSS. 58 yo lady status post therapeutic PK (10 mm graft). Immediate post-op clear graft but at 2 months : corneal edema with TDMD in superior quadrant associated with graft-host junction synechiae. Long acting SF6 failed to appose DM. Pre-op ASOCT Post op ASOCT Post op day 1

8. Case 2 Multiple small relaxing Descemetotomy incisions made superiorly under air. Air then exchanged with long acting gas (C3F8, 14%) Face up positioning for 1 hour 27 yo female with peripheral corneal thinning and ectasia presented with traumatic rupture globe & inferior corneal tear. Underwent corneal tear suturing Seven weeks later: corneal edema/ epithelial bedewing secondary to TDMD stretching upwards from the wound and iris adhered to wound PRE-OP ASOCT POST-OP ASOCT Pre-op: Gas tamponade alone was not successful. Post-op day 1

9. DISCUSSION • DMD is occasionally faced by the ophthalmologist after surgery. • Various techniques have conventionally been proposed: • observation • viscoelastic injection • air injection and the use of long acting intra-cameral gas • trans-corneal mattress sutures SDMD DMD can be classified as SDMD and TDMD and management should be tailored according to the type of DMD. TDMD

10. DISCUSSION • DMD previously classified as planar or nonplanar based on morphology • We propose new classification of DMD based on etio-pathogenesis • Stripped Descemet’s Membrane Detachment (SDMD) • Taut Descemet’s Membrane Detachment (TDMD) • This new classification helps in guiding management of DMD

12. CONCLUSIONS • TDMD needs to be differentiated from SDMD as management differs. • Relaxing Descemetotomyis the treatment of choice for TDMD • Relaxing descemetotomy incisions act by breaking stress forces acting on the DM. The tautness of the DM is relieved and air or gas bubble is able to appose the now lax DM against the overlying corneal stroma. TDMD SDMD DMD can be classified based on etio-pathogenesis as either Stripped Descemet’s Membrane Detachment (SDMD) or a Taut Descemet’s Membrane Detachment (TDMD). This classification helps in guiding the line of management