PMID- 28937143
OWN - NLM
STAT- MEDLINE
DCOM- 20180723
LR  - 20180723
IS  - 1476-5454 (Electronic)
IS  - 0950-222X (Linking)
VI  - 32
IP  - 1
DP  - 2018 Jan
TI  - Crab claw pattern on corneal topography: pellucid marginal degeneration or
      inferior keratoconus?
PG  - 11-18
LID - 10.1038/eye.2017.198 [doi]
AB  - PurposeTo evaluate the topographic, tomographic, and densitometric properties of 
      patients with pellucid marginal degeneration (PMD) and inferior
      keratoconus.Patients and methodsRetrospective, comparative case series.
      Forty-seven eyes of 32 patients with crab claw patterns were identified from 2751
      patients with corneal ectasia. They were divided into two groups, inferior
      keratoconus and PMD, based on clinical findings. The topographic, tomographic,
      and densitometric measurements were analyzed.ResultsPMD was detected in 11 eyes
      of eight patients (mean age 50.2+/-11.1 years), and inferior keratoconus was
      detected in 36 eyes of 24 patients (mean age 34.7+/-10.1 years). The control
      group consisted of 40 patients (33.1+/-4.6 years). The thinnest corneal point and
      maximum anterior and posterior elevation points were located lower in the PMD
      than in the inferior keratoconus (P<0.01). In the PMD, all deviation indices were
      higher than the controls (P<0.01), whereas the deviation indices, except Dt
      (P=0.960), were lower than the inferior keratoconus (P<0.01). The densitometry
      values of PMD were significantly higher than those of the controls in all zones
      and layers (P<0.01) and significantly higher than the densitometry values of
      inferior keratoconus in the 6-10 and 10-12 mm zones (P<0.05).ConclusionThere is a
      higher probability of a patient with crab claw pattern on the topography of
      having inferior keratoconus than having PMD. Therefore, analyzing only the
      anterior corneal surface is not sufficient in differential diagnosis. Tomographic
      and densitometric evaluations may facilitate the differential diagnosis.
FAU - Koc, M
AU  - Koc M
AD  - Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital,
      Ankara, Turkey.
FAU - Tekin, K
AU  - Tekin K
AD  - Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital,
      Ankara, Turkey.
FAU - Inanc, M
AU  - Inanc M
AD  - Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital,
      Ankara, Turkey.
FAU - Kosekahya, P
AU  - Kosekahya P
AD  - Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital,
      Ankara, Turkey.
FAU - Yilmazbas, P
AU  - Yilmazbas P
AD  - Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital,
      Ankara, Turkey.
LA  - eng
PT  - Comparative Study
PT  - Journal Article
DEP - 20170922
PL  - England
TA  - Eye (Lond)
JT  - Eye (London, England)
JID - 8703986
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Cornea/*pathology/physiopathology
MH  - Corneal Topography/*methods
MH  - Cross-Sectional Studies
MH  - Densitometry/*methods
MH  - Female
MH  - Follow-Up Studies
MH  - Humans
MH  - Keratoconus/*pathology/physiopathology
MH  - Male
MH  - Middle Aged
MH  - Refraction, Ocular/*physiology
MH  - Retrospective Studies
MH  - Severity of Illness Index
MH  - Tomography, Optical Coherence/*methods
MH  - Young Adult
PMC - PMC5770716
EDAT- 2017/09/25 06:00
MHDA- 2018/07/24 06:00
CRDT- 2017/09/23 06:00
PMCR- 2019/01/01 00:00
PHST- 2016/12/19 00:00 [received]
PHST- 2017/08/01 00:00 [accepted]
PHST- 2019/01/01 00:00 [pmc-release]
PHST- 2017/09/25 06:00 [pubmed]
PHST- 2018/07/24 06:00 [medline]
PHST- 2017/09/23 06:00 [entrez]
AID - eye2017198 [pii]
AID - 10.1038/eye.2017.198 [doi]
PST - ppublish
SO  - Eye (Lond). 2018 Jan;32(1):11-18. doi: 10.1038/eye.2017.198. Epub 2017 Sep 22.