Corneal innervation changes in Alzheimer's: implications for sensory dysfunction.

PURPOSE: To compare, between Alzheimer's disease (AD) patients and healthy individuals, corneal subbasal nerve plexus (CSNP) parameters and corneal sensitivities. METHODS: Twenty-two patients who were followed up with Alzheimer's disease (Alzheimer's group) and 18 age- and gender-matched healthy individuals (control group) were included in this cross-sectional study. CSNP parameters, including nerve fiber length (NFL), nerve fiber density (NFD), and nerve branch density (NBD), were evaluated using in vivo confocal microscopy. Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. The results were compared between the two groups. RESULTS: In the Alzheimer's group, NFL was 12.2 (2.4) mm/mm2, NFD was 12.5 [3.1] fibers/mm2, and NBD was 29.7 [9.37] branches/mm2. In the control group, NFL was 16.5 (2.0) mm/mm2, NFD was 25.0 [3.13] fibers/mm2, and NBD was 37.5 [10.9] branches/mm2. All three parameters were significantly lower in the Alzheimer's group compared to the control group (p < 0.001, p < 0.001, and p = 0.001, respectively). Similarly, corneal sensitivity was significantly lower in the Alzheimer's group (55.0 [5.0] mm) compared to the control group (60.0 [5.0] mm) (p < 0.001). CONCLUSION: We determined that, in AD, corneal sensitivity decreases significantly, in parallel with the decrease in corneal nerves. Changes in the corneal nerve plexus and a decrease in corneal sensitivity may be used in the early diagnosis and follow-up of AD. In addition, ocular surface problems secondary to these changes should also be kept in mind.

Triglyceride Glucose Index: A Potential Indicator in the Evaluation of Graves Ophthalmopathy.

PURPOSE: To determine the relationship between Graves ophthalmopathy (GO) and triglyceride glucose index (TGI) and to evaluate the predictive importance of this index in terms of GO activity. METHODS: This retrospective study included 20 inactive GO patients, 20 active GO patients, and 20 healthy controls. TGI was calculated using fasting plasma triglyceride and fasting plasma glucose levels and values were compared between the groups. The receiver operating characteristics curve was used to calculate the optimal TGI cutoff value and the sensitivity and specificity of this value between active and inactive GO groups. RESULTS: No significant difference was detected between the groups in terms of age and gender (p = 0.561 and p = 0.762, respectively). TGI value was 8.49 (8.41, 8.67) in the control group, 8.76 (8.74, 8.87) in the inactive GO group, and 9.06 (8.87, 9.08) in the active GO group (p < 0.001 for control group vs. inactive GO group; p < 0.001 for control group vs. active GO group; p = 0.001 for inactive GO group vs. active GO group). The optimal receiver operating characteristics cutoff value of TGI between active and inactive GO groups was 8.86 with 85% sensitivity and 75% specificity (area under curve: 0.837, p < 0.001, 95% confidence interval: 0.711-0.964). CONCLUSION: TGI was higher in both inactive and active GO patients compared with controls. It also appears that TGI may be used as a predictive marker indicating GO activity. This cheap and easily accessible parameter may be beneficial in detecting the disease and monitoring its activity in clinical practice.