1. Contrast-Enhanced Corneal Wound Imaging by Optical Coherence Tomography Preeya K. Gupta, MD Justis P. Ehlers, MD Terry Kim, MD Duke Eye Center, Durham, NC Cole Eye Institute, Cleveland, OH Financial Disclosures: none

2. Background Modern cataract surgery has shifted from scleral incisions to clear corneal incisions (CCI) as today’s standard of care. While these incisions offer reduced surgical time and faster visual recovery, wound construction and integrity is critical to preventing complications, such as wound leakage and endophthalmitis. Cadaveric studies of CCI have suggested that ingress of fluid may occur. However, no prior study to date has examined in vivo CCI integrity.

3. Purpose To evaluate post-phacoemulsification clear corneal wound morphology and integrity using contrast-enhanced SD-OCT both immediately after surgery and 24 hours post-operatively.

4. Methods Prospective cohort study including 18 patients (n=18 eyes) undergoing unilateral routine cataract surgery SD-OCT imaging (Cirrus™, Carl Zeiss Meditec Inc, Dublin, CA) of the corneal wound was performed on all patients immediately following cataract surgery and on post-operative day one A topical contrast agent, prednisolone acetate 1% (PA), was used to help evaluate wound integrity. OCT features of the corneal incision were analyzed, as well as changes in wound interface reflectivity after administration of topical PA.

5. Methods Volume scans and five-line raster scans were performed before and after application of PA. All scans were centered on the corneal wound. Main outcome measures were quantitative and qualitative description of wound morphology and contrast enhancement of the wound interface. Qualitative analysis of OCT features included presence of internal wound gape, external wound gape, Descemet’s membrane detachments, and contrast enhancement following PA. ImageJ software was used to analyze wound architecture.

6. Results Internal wound gape was found in 89% of eyes Gape area decreased by 43% from day 0 to 1 (462 µ2 vs. 273µ2 p< 0.01) Figure 1: SD-OCT image of clear corneal incision wound gape (a) post-operative day 0, (b) post-operative day 1. (b)(a)

7. Results Contrast enhancement at the wound interface was seen in 56% of eyes on day 0 compared to 17% on day 1 following application of PA (p< 0.05) Contrast enhancement in uniplanar wounds (6/6, 100%) was significantly higher than in biplanar wounds (6/13, 43%, p = 0.05) (a) (b) * Figure 2: Clear corneal wound interface (a) prior to application of prednisolone acetate and (b) post application of prednisolone acetate. Note increased reflectivity in the wound interface (*)

8. Results Decreased intraocular pressure correlated with increased contrast enhancement (p< 0.05) Figure 3: (a) Clear corneal wound interface on post-operative day 0 in a patient with IOP=4. (b) Clear corneal wound interface on post-operative day 0 in a patient with IOP=29. Note the increased reflectivity in the wound interface in the patient with lower intraocular pressure and greater wound gape in patient with lower IOP. (a) (b)

9. Table 1: Subject demographic and clinical characteristics Patient EyeGenderIncision Type Cataract Grade CDEIOP POD 0 IOP POD 1 Change in IOP 1RMbiplanar25.771917-2 2LMbiplanar36.58142511 3RFbiplanar1.54.672812-16 4RFbiplanar2.55.222014-6 5RMbiplanar2.57.9115172 6RFbiplanar11.8916193 7RMbiplanar314.78495 8LFbiplanar2.57.672825-3 9RFbiplanar27.356148 10RFbiplanar2.5NA17225 11LFbiplanar1.51.882314-9 12LFbiplanar25.1513152 13LFBiplanar212.23109 14LMUniplanar1.59.8851712 15LMUniplanar1.515.72926-3 16RFUniplanar210.95122311 17RMUniplanar1.519.5664337 18RMUniplanar332.33102212

10. Table 2. OCT features of all clear corneal incisions (n=18) Wound Visible Internal Wound Gape Present External Wound Gape Present Internal Tissue Overhang Descemet’s Detachment Subepithelial Fluid Contrast seen on Surface Subjective appearance of contrast in the wound POD 018 (100%)16 (89%) 4 (22%)2 (11%)11 (61%)5 (28%)18 (100%)17 (94%) POD 118 (100%)16 (89%) 5 (28%)2 (11%)11 (61%)7 (39%)17 (94%)13 (72%) Table 3. OCT features varied by clear corneal incision architecture Incision construction Wound Visible Internal Wound Gape External Wound Gape Internal Tissue Overhang Descemet’s Detachment Subepithelial Fluid Contrast seen on Surface Subjective appearance of contrast in the wound Biplanar POD 0 (n=13) 13 (100%) 2 (15%)0 (0%)6 (46%)4 (31%)13 (100%)10 (77%) Uniplanar POD 0 (n=5) 5 (100%)3 (60%) 2 (40%)5 (100%)3 (60%)5 (100%)3 (60%) 2.2mm Incision (n=14) 14 (100%)13 (93%)4 (29%)1 (7%)9 (64%)4 (29%)14 (100%)11 (79%) >2.5 mm incision (n=4) 4 (100%)3 (75%)1 (25%) 2 (50%)3 (75%)4 (100%)2 (50%)

11. Conclusions Wound morphology evolves during the early postoperative period. Wound gape and ingress of a topical contrast agent decrease during the first 24 hours following surgery. Contrast enhancement at the wound interface increases as the intraocular pressure decreases.