Scientists analyzed systemic and ocular determinants of peripapillary retinal nerve fiber layer thickness (pRNFLT) in a European population, as part of a cross-sectional meta-analysis.

They included 16,084 European adults from eight cohort studies (mean age range, 56.9 ±12.3 to 82.1±4.2 years) of the European Eye Epidemiology consortium. Scientists examined associations with pRNFLT measured by spectral-domain OCT using multivariable linear regression and pooled results from random effects meta-analyses. Main outcome measures included determinants of pRNFLT.

Mean pRNFLT ranged from 86.8 ±21.4 μm in the Rotterdam Study I to 104.7 ±12.5 μm in the Rotterdam Study III. Scientists found the following factors to be associated with reduced pRNFLT:
• older age (β=-0.38 μm/year; CI, -0.57 to -0.18);
• higher intraocular pressure (β=-0.36 μm/mmHg; CI, -0.56 to -0.15);
• visual impairment (β=-5.50 μm; CI, -9.37 to -1.64);
• history of systemic hypertension (β=–0.54 μm; CI, -1.01 to -0.07); and stroke (β=–1.94 μm; CI, -3.17 to -0.72).
• A suggestive, non-significant association was observed for dementia (β=-3.11 μm; CI, -6.22 to 0.01).
• Higher pRNFLT was associated with more hyperopic spherical equivalent (β=1.39 μm/diopter; CI, 1.19 to 1.59) and smoking (β=1.53 μm; CI, 1 to 2.06) for current smokers compared with never-smokers.

In addition to previously described determinants such as age and refraction, researchers found that systemic vascular and neurovascular diseases were associated with reduced pRNFLT. They wrote that these factors might be of clinical relevance, especially in monitoring glaucoma with newly occurring vascular comorbidities.

Researchers determined the formation frequency of various bubble types, the potential impacts of donor and lamella parameters on frequency, and possible risk factors for unsuccessful “big-bubble” creation, in preparation for pre-Descemet’s endothelial keratoplasty with peripheral stromal support and using the big-bubble technique.

Donor age and sex, death-to-preservation time, storage time, presence of corneal scars (mainly a condition after cataract surgery) and endothelial cell density of 256 donor corneas were assessed before the procedures.

• Mean donor age was 62.3 ±8.5 years (28.3 percent women and 71.7 percent men).
• Mean endothelial cell density of the donor grafts was 2,866 ±255 cells/mm².
• Mean death-to-preservation time was 10.12 ±4.88 hours, and mean storage time of the transplant before surgery was 6.5 ±4.8 days.
• Corneal scars were present in 17 donor grafts (6.6 percent) after cataract surgery; 11 corneas (4.3 percent) were devalued because of Descemet’s membrane rupture during preparation.
• Standard bubble type I was created in 182 corneas (71.7 percent); bubble type II was created in 27 corneas (9.9 percent); both bubble types formed simultaneously in several cases (10.5 percent); and no bubble was created in 47 corneas (18.4 percent).

Researchers identified higher endothelial cell density, shorter death-to-preservation time and the presence of corneal scars after cataract surgery as risk factors threatening bubble formation. They noted that the only risk factor in this study for creating type II bubbles was higher donor age.