Evolving Techniques in Partial Endothelial Keratoplasty: A Comprehensive Literature Review

Individuals with endothelial disorders such as Fuchs’ corneal dystrophy and bullous keratopathy require corneal transplantation of the diseased corneal tissue once their endothelial cell density has decreased significantly. In the past century, penetrating keratoplasty (PK) or full corneal transplantation has been the most widely used procedure to treat endothelial dysfunction. However, endothelial keratoplasty (EK) has replaced PK as it has lower post-operative complications. EK consists of Descemet’s stripping endothelial keratoplasty (DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK). This study consists of a literature review on the advantages and disadvantages of DMEK and DSEK and their post-operative complications. Patients who undergo the DMEK procedure experience lower rates of graft rejection, more frequent re-bubbling and follow-up appointments, and faster visual recovery period. Patients who undergo the DSEK procedure have higher rates of graft rejection, longer visual recovery period, and less re-bubbling rates and follow-up appointments. Surgical techniques for repairing endothelial dysfunction are evolving, but we need larger long-term studies to prove that new techniques are superior to the current surgical techniques

No association between cortical lesions and leptomeningeal enhancement on 7-Tesla MRI in multiple sclerosis

Background: Autopsy data suggest a causative link between meningeal inflammation and cortical lesions (CLs) in multiple sclerosis (MS). Objective: To use leptomeningeal enhancement (LME) and CLs on 7-Tesla (7T) magnetic resonance imaging (MRI) to investigate associations between meningeal inflammation and cortical pathology. Methods: Forty-one participants with MS underwent 7T MRI of the brain. CLs and foci of LME were quantified. Results: All MS participants had CLs; 27 (65.8%) had >1 focus of LME. Except for hippocampal CL count (ρ = 0.32 with spread/fill-sulcal pattern LME, p = 0.042), no significant correlations were seen between LME and CLs. Mean cortical thickness correlated with the number of LME foci (ρ = –0.43, p = 0.005). Participants with relapsing–remitting multiple sclerosis (RRMS) showed no correlation with neocortical CLs, but significant correlations were seen between LME and hippocampal lesion count (ρ = 0.39, p = 0.030), normalized cortical gray matter (GM) volume (ρ = –0.49, p = 0.005), and mean cortical thickness (ρ = –0.59, p < 0.001). Conclusion: This study supports a relationship between LME and cortical GM atrophy but does not support an association of LME and neocortical CLs. This may indicate that meningeal inflammation is involved with neurodegenerative inflammatory processes, rather than focal lesion development

Testing a Popular Smartphone Application for Colour Vision Assessment in Healthy Volunteer Subjects.

We aimed to compare the Ishihara pseudoisochromatic colour vision test with a colour vision test from a popular smartphone application (EyeHandBook [EHB]) using digital image processing to simulate colour vision deficiencies. Three digital versions of the Ishihara and EHB slides were created: full colour; 32 bit- greyscale (removing all colour information); and blue channel (to simulate red-green colour vision deficiencies). Twenty healthy volunteers were shown each colour-edited plate. The answers they reported were compared with what would be expected for that colour-simulation scenario based on the answer key provided in the Ishihara booklet ( expected answer). There were nine plates that had comparable patterns between the EHB and Ishihara test. We found no significant difference in the overall proportion of expected answers for the full colour (p = .35), 32 bit-greyscale (p = .39) and blue channel (p = .22) conditions. There were significant differences between the proportion of expected answers among six individual colour- edited plates (p \u3c .05 for each). Colour vision assessment from the EHB is distinct from comparable Ishihara plates. Clinical scenarios that require serial assessment of colour vision may benefit from using the same modality consistently rather than exchanging between the two tests with the assumption of equivalence. Refinement of digital colour editing techniques beyond 32-bit greyscale and RGB channel splitting is necessary in order to accurately simulate colour vision deficiency