Inactivity is a recognized compounding factor in sarcopenia and muscle weakness in old age. However, while the negative effects of unloading on skeletal muscle in young individuals are well elucidated, only little is known about the consequence of immobilization and the regenerative capacity in elderly individuals. Thus the aim of this study was to examine the effect of aging on changes in muscle contractile properties, specific force, and muscle mass characteristics in 9 old (61-74 yr) and 11 young men (21-27 yr) after 2 wk of immobilization and 4 wk of retraining. Both young and old experienced decreases in maximal muscle strength, resting twitch peak torque and twitch rate of force development, quadriceps muscle volume, pennation angle, and specific force after 2 wk of immobilization (P < 0.05). The decline in quadriceps volume and pennation angle was smaller in old compared with young (P < 0.05). In contrast, only old men experienced a decrease in quadriceps activation. After retraining, both young and old regained their initial muscle strength, but old had smaller gains in quadriceps volume compared with young, and pennation angle increased in young only (P < 0.05). The present study is the first to demonstrate that aging alters the neuromuscular response to short-term disuse and recovery in humans. Notably, immobilization had a greater impact on neuronal motor function in old individuals, while young individuals were more affected at the muscle level. In addition, old individuals showed an attenuated response to retraining after immobilization compared with young individuals.

. Purpose:  To investigate the incidence and cause of severe visual loss following use and removal of intraocular silicone oil (SiO) after uncomplicated vitrectomy and SiO injection for primary rhegmatogenous retinal detachment (RRD). Methods:   Consecutive case series of 216 patients operated with vitrectomy for primary RRD in 2004–2005. In 162 eyes, SiO (5500 centiStoke) had been used as intravitreal tamponade and in 54 eyes gas (perflouropropane, C3F8) had been used. Following chart review, we identified 16 eyes in 16 patients (nine SiO eyes, seven gas eyes) with macula‐on and documented visual acuity ≥6/12 before surgery, where SiO had been removed, cataract surgery performed and no re‐detachment had occurred. Examinations included best‐corrected visual acuity (BCVA) and high‐definition optical coherence tomography (OCT) of the macular area. Results:  Preoperative characteristics were identical between SiO and gas eyes. Postoperative BCVA was significantly worse in SiO eyes (>6/24) compared to gas eyes (>6/7.5), p = 0.005. Three of 9 (33%) SiO eyes had final BCVA ≤6/60 and 67% had final BCVA ≤6/12. No gas eyes had final BCVA <6/9. Macular OCT revealed thinning of inner retinal layers in SiO‐operated eyes (5148 pixels) compared to gas‐operated eyes (6897 pixels), p < 0.002. No other visually significant structural differences were found. Conclusion:  Severe visual loss after SiO use was observed in 1/3 of patients with otherwise good visual potential. The visual loss was associated with a significant reduction in inner retinal thickness indicating neuronal cell loss in the macular area as a possible explanation.