Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Novel grid and sectoral analyses for corneal scar evaluation

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Session Details

Session Title: Presented Poster Session: Anterior Segment Imaging

Session Date/Time: Monday 12/09/2016 | 09:30-11:00

Paper Time: 10:00

Venue: Poster Village: Pod 4

First Author: : A.Young HONG KONG

Co Author(s): :    R. Kwok   K. Kam           

Abstract Details


We proposed two novel methods to evaluate corneal scars using the Pentacam densitometry and compared to default analyses provided by the software itself. We hypothesize that these novel methods would increase the sensitivity and specificity in capturing the true changes in the corneal scars.


Teaching University Tertiary referral eye centre in Hong Kong


This is a retrospective analysis (from our earlier prospective published study) on patients who received primary pterygium excision with topical mitomycin-C. Ethics approval was obtained. Serial Scheimpflug images were captured by Pentacam® (OCULUS Optikgeräte GmbH, Wetzlar Germany) at postoperative one, four, twelve weeks and eighteen months. Instead of utilizing the intrinsic total-diameter average densitometry of the anterior layer as primary outcome, we devised two novel methods- grid and sector, to sample relevant points in both scarred area and opposite clear pole of the same cornea, excluding artefacts or missing data to minimise any confounding effect of adopting total-diameter analyses.


30 eyes of 30 patients were included. Mean densities sampled by grid method were 39.0 Grayscale Units (GSU), 37.1GSU, 36.7GSU and 34.7GSU at weeks 1, 4, 12 and month 18. Mean densities sampled by sector method were 35.3GSU, 33.3GSU, 32.5GSU and 31.9GSU respectively. Density reduction at scarred area was significant at all follow-ups time points up to month 18 (P<0.05). For control values, smaller absolute reductions in density were shown by both methods. Grid method revealed a mean reduction of 1.9GSU (versus 4.3GSU in scarred side) while sector method showed a mean reduction of 2.1GSU (versus 3.4GSU) at 18 months.


The grid and sector methods appeared to be at least comparable to the conventional total-diameter analyses in detecting true changes occurring at different portions of the cornea, evidenced by the greater statistical significance achieved at all time points and exclusion of irrelevant areas or artefacts. The rate and magnitude of density reduction in the scars were greater than the clear pole of the same corneae. As the clear pole of cornea showed reduction in density following surgery, postoperative topical corticosteroid therapy may be able to modulate the overall density of the cornea.

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