Validation of the multi-metric D-index change in the assessment of keratoconus progression.

PURPOSE: To validate the effectiveness of the multi-metric D-index by Pentacam in detecting keratoconus (KC) progression. MATERIALS AND METHODS: This was a retrospective study of KC patients at the Rabin Medical Center, Petah Tikva, Israel, during 2016-2018 with at least two corneal tomography examinations six months apart. Agreement between clinical diagnosis of progression (1.5D increase in mean keratometric value, 1D increase in Kmax, a 5% decrease in central corneal thickness (CCT), worsening of visual acuity by more than one line, or deterioration of manifest corneal astigmatism > 1.5D) and the D-index was evaluated. Receiver operating characteristic (ROC) analysis was used to find the D-index's optimal cutoff value to show progression. RESULTS: We included KC eyes in the stable group (N = 7) and the progression group (N = 54). Patient demographics and tomographic parameters at baseline were similar between the groups. The D-index change was significantly higher in the progression group than in the stable group (median + 1 and 0.0, respectively, p = 0.024). Based on the ROC analysis, the optimal D-index cutoff change within at least six months was 0.32 (59.3% sensitivity and 100% specificity (area under the curve [AUC] = 0.771, Youden = 0.592). Subjects with a D-index change above this value had a 21.1-fold increase in odds for corneal ectasia progression requiring CXL (OR: 21.1, 95%CI 1.17-398.8, p = 0.038). CONCLUSION: The multi-metric D-index can serve as a clinically feasible parameter to detect KC progression and guide patients' referral for further interventions.

Changes in Prices and Eye-Care Providers Prescribing Patterns of Glaucoma Medications in the United States Between 2013 and 2019.

PRECIS: Brand glaucoma medication prices vastly increased in the United States over the past 7 years, despite a reduction in eye-care providers' tendency to prescribe brand medications over generics. PURPOSE: Determine the changes in prices of brand and generic glaucoma medications and to identify changes in eye-care providers prescribing patterns since 2013. MATERIALS AND METHODS: The National Average Drug Acquisition Cost (NADAC) database (2013-2019) was used analyze per-unit drug price. Medicare Part D prescriber profile was used to identify eye-care providers prescribing patterns between 2013 and 2017. RESULTS: Brand-name medication prices increased by 59% between 2013 and 2019, while generic medications decreased by 22%. Brand-name drugs were 13 to 162 times more expensive than their generic counterparts. Eye-care Providers prescribed 25% less brand name medications in 2017 compared with 2013. CONCLUSION: Brand glaucoma medication prices vastly increased in the United States over the past 7 years, despite a reduction in eye-care providers' tendency to prescribe brand medications over generics. A change in government policy, allowing Medicare medication prices negotiations, could greatly reduce health expenditure on glaucoma treatment.

Polarimetric Interferometry for Assessment of Corneal Stromal Lamellae Orientation.

PURPOSE: To analyze corneal stromal lamellae orientation in normal subjects and patients with various corneal conditions using a polarimetric interferometer. METHODS: Thirty-two healthy control subjects (59 eyes) and 16 patients (22 eyes) with corneal conditions or postkeratoplasty were included in the study. All patients were imaged using the interferometer and slit lamp photography. The interferometer produces an orthogonal cross-like image of stromal lamellae by illuminating the cornea in phase-light polarization angle. Corneal haze was graded on a scale from 0 to 4. Interferometer cross-like images were graded on a scale from 0 to 5 by a masked observer. Keratometry, corneal central pachymetry, and optical densitometry were obtained with Scheimpflug corneal tomography. RESULTS: The cross-like image was observed in 31 of 32 healthy control subjects (58 of 59 eyes) and in 13 of 16 patients (19 of 22 eyes). The image was not detectable in 3 patients, 1 with total corneal neovascularization and scarring, 1 with central leukoma, and 1 with failed deep lamellar keratoplasty. Corneal haze was the main factor obscuring the cross-like image (P < 0.05). Clarity of the images was influenced by older age, steeper keratometry, higher pachymetry, and optical density (P < 0.05). There was no correlation between the orientation of the keratometric axes and the orientation of the 2 arms of the cross-like image (P > 0.05). CONCLUSIONS: Corneal stromal lamellae orientation can be efficiently assessed and displayed as a cross-like image by the polarimetric interferometer. Stromal lamellae orientation imaging may have potential implications in corneal diagnostics and surgery.