| Title:
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A New Topographic Pattern to Early Differentiate Pellucid Marginal Degeneration from Keratoconus
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| Author(s):
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Mohammad Reza Jafarinasab, MD; Sepehr Feizi, MD, MSc; Sare Safi, MSc
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| Presentation Type:
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Oral
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| Subject:
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Cornea and Refractive
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| Others:
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Presenting Author:
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| Name:
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Mohammad reza Jafarinasab
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| Affiliation :(optional)
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Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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| E mail:
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dr_jafarinasab@yahoo.com
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| Phone:
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982122802430
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Mobile: |
09121021448
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Abstract (Max 200 words)
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| Purpose:
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To introduce a new topographic sign which can help to early discriminate pellucid marginal degeneration (PMD) from keratoconus (KCN).
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| Methods:
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This cross-sectional study consisted of 20 patients with bilateral but asymmetric PMD; one eye had early form of disease whereas, PMD was more advanced in the fellow eye. Computerized corneal topography or dual-Scheimpflug analyzer were performed in these eyes. Topographic pattern and indices were analyzed to differentiate the early stage of PMD from KCN.
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| Results:
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Based on the corneal topography and tomography the diagnosis of PMD was equivocal in one eye but clear in the fellow eye with the more advanced disease. We could describe a topographic pattern which was useful in discriminating early PMD in 90% of the eyes. This pattern which looked like an apple (apple sign) constantly had three portions; a flat stem, a steep core and an average skin portion. The border of pattern (skin of apple) had an average power (yellow-green color). The flat small line (cold colored line surrounded by hot colors) compatible with internal stem and flattest area was similar to external stem (coldest color) located in superior part of map. The steepest portion was at the core (hottest color) of the apple. With progress of PMD the steep core replacing by flat core and steep core displays to the peripheral area.
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| Conclusion:
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The apple pattern observed in corneal topographic map, especially in sagittal and instantaneous map, is a useful sign for the early diagnosis of PMD. Changes of steep and flat areas inside the apple pattern is a good indication of disease progression. A prospective study is now underway to confirm the clinical implications of this pattern.
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| Attachment:
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