images of pellucid marginal degeneration

Images of pellucid marginal degeneration manual#

Keratoconus is characterized by progressive corneal protrusion and thinning, leading to irregular astigmatism and impairment in visual function. Tomographic and densitometric evaluations may facilitate the differential diagnosis.Eye advance online publication, 22 September 2017 doi:10.1038/eye.2017.198. Therefore, analyzing only the anterior corneal surface is not sufficient in differential diagnosis. There is a higher probability of a patient with crab claw pattern on the topography of having inferior keratoconus than having PMD. 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).Conclusion 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 thinnest corneal point and maximum anterior and posterior elevation points were located lower in the PMD than in the inferior keratoconus (P<0.01). The control group consisted of 40 patients (33.1±4.6 years). The topographic, tomographic, and densitometric measurements were analyzed.ResultsPMD was detected in 11 eyes of eight patients (mean age 50.2☑1.1 years), and inferior keratoconus was detected in 36 eyes of 24 patients (mean age 34.7☑0.1 years). They were divided into two groups, inferior keratoconus and PMD, based on clinical findings. Forty-seven eyes of 32 patients with crab claw patterns were identified from 2751 patients with corneal ectasia. All rights reserved.PurposeTo evaluate the topographic, tomographic, and densitometric properties of patients with pellucid marginal degeneration (PMD) and inferior keratoconus.Patients and methodsRetrospective, comparative case series. A thickening of the mCTi and a flattening in the inferior part of the cornea was observed.Ĭopyright © 2019 ASCRS and ESCRS.

Images of pellucid marginal degeneration manual#

Manual pachymetric measurements in Scheimpflug images showed the potential for screening for PMD and the evaluation of the efficacy of CXL in eyes with PMD in the study cohort. The corneal astigmatism continuously decreased, and the CDVA improved after 1 year. The K value in the 2.5 mm zone of the inferior cornea decreased after 1 year, whereas the K value in the central zone of 5.0 mm remained stable. The mCTi increased during the 12-month follow-up. Twenty-two eyes matched the inclusion criteria for PMD and 16 eyes underwent CXL. Patients were followed postoperatively for 12 months.įorty-eight eyes showed a crab-claw pattern in corneal topography. The corrected distance visual acuity (CDVA) was also evaluated.

During the follow-up, the mCTi, the mean keratometry (K) values in a central zone of 5.0 mm and in a 2.5 mm zone of the inferior cornea and the topographical corneal astigmatism were measured. CXL was performed by irradiation of the inferior periphery of the cornea. A ratio between mCTi and mCTs was calculated. Eyes with paralimbal thinning were supposed as having PMD and included. In eyes with a crab-claw pattern on corneal topography of a study cohort of 808 eyes, manual measurements of the cornea's thinnest point on the inferior vertical Scheimpflug image (mCTi) and on the superior vertical Scheimpflug image (mCTs) were conducted. To investigate the efficacy of corneal crosslinking (CXL) for pellucid marginal degeneration (PMD).