Preoperative geometric parameters predict the outcome of lamellar keratoscleroplasty in patients with limbal dermoids.

PURPOSE: To find preoperative simple geometric parameters to predict the outcome of lamellar keratoscleroplasty in patients with corneal limbal dermoids. METHODS: We retrospectively analyzed the data of 30 patients with limbal dermoids who underwent lamellar keratoscleroplasty and were followed up for more than 6 months. Seven geometric parameters were used to analyze the relationship with postoperative visual acuity, astigmatism, and scar formation and investigated for their influence on postoperative outcome. These seven parameters included the cornea-invaded area of dermoid, dermoid area, the cornea-invaded length of dermoid, the corneal limbus invaded length of dermoid, dermoid size, bed size, graft size. Furthermore, we divided patients with corneal limbal dermoids into amblyopia group and non-amblyopia group, and analyzed the clinical characteristics of the amblyopia group. RESULTS: The mean age of the patients at surgery was 10.6 ± 5.83 years. The 7 geometric parameters, preoperative and postoperative astigmatism of the amblyopia group were higher than those of the non-amblyopia group (all P < 0.05). Among the geometric parameters analyzed, the r coefficients between the cornea-invaded length of dermoid and postoperative visual acuity and astigmatism were the highest (r = 0.854, r = 0.714). The r coefficient between the corneal limbus invaded length of dermoid and the postoperative scar was the highest (r = 0.375). The r coefficient between age and postoperative steroid-induced high intraocular pressure was the highest (r = - 0.416). In univariate regression analysis, the cornea-invaded length of dermoid was significantly correlated with postoperative visual acuity (ß = 0.270, P < 0.001) and postoperative astigmatism (ß = 1.362, P < 0.001). Among the geometric parameters analyzed, the cornea-invaded length of dermoid had best stratified patients in grouping with or without amblyopia (cutoff > 2.24). CONCLUSION: The cornea-invaded length of dermoid was the most important related factor of postoperative visual acuity, astigmatism, and amblyopia. The corneal limbus invaded length of dermoid was the most important related factor of postoperative scar formation. The geometric parameters and astigmatism in patients with amblyopia were larger than those in patients without amblyopia.

Canalicular laceration repair with a novel bicanalicular silicone tube.

PURPOSE: This study aimed to investigate the efficacy and safety of canalicular laceration repair using a novel bicanalicular silicone tube. METHODS: Retrospective and consecutive patients who underwent canalicular laceration repair using novel Runshi-RS bicanalicular silicone stents from January 2020 to February 2021 were included. The stent was placed for 3 months, and patients were followed up for more than 3 months after extubation. Demographics, causes of eyelid injuries, placement time and position of stent, and surgical outcomes at follow-up were recorded. Anatomical success was evaluated by diagnostic probing and irrigation of lacrimal passage, while functional success was evaluated by the patient's subjective symptoms of epiphora. RESULTS: This study included 43 patients with canalicular laceration. The median age was 43 years (3-75 years). The average duration of stent implantation was 12.9 weeks, and the follow-up time was 8.8 months. No complications were observed in any patients during operation and follow-up. After extubation, irrigation of the lacrimal passage in 43 eyes showed no obstruction, and the anatomical success rate was 100%. Overall, 39 patients (90.7%) had no subjective symptoms of epiphora. All patients got good cosmetic results. Furthermore, subgroup classification showed deep laceration group (distance from laceration to punctum>5 mm) accounted for 51.2%, and the functional success rate of the deep laceration group was lower than that of the shallow laceration group. CONCLUSION: Runshi-RS bicanalicular silicone stent achieved good anatomical (100%) as well as functional (90.7%) success and good cosmetic results (100%) in patients with canalicular laceration repair.

Performance characterization of fiber Bragg grating thermal response in space vacuum thermal environment.

We investigated the fiber Bragg grating (FBG) thermal response in space vacuum thermal environment. The FBGs were packaged with 6061-T6 aluminum. The liquid nitrogen immersion experiment results show that its wavelength shift standard deviation is 0.76 pm for 217 h. The combination effect of vacuum and cryogenic temperature was studied by thermal cycling process in space environment simulator. The FBG sensors show accuracy better than 2% full scale, and the hysteresis errors are below 1%. It proves that these metal packaged FBG sensors can survive and meet the requirement of space measurement.

[Impact of loss of sympathetic innervation on peripheral nerve regeneration: an experimental study with rats].

OBJECTIVE: To investigate the impact of loss of sympathetic innervation on peripheral nerve regeneration. METHODS: Thirty-two SD rats underwent resection of the right middle cervical ganglion and excision and re-anastomosis of bilateral medium nerve, and then were randomly divided into 4 equal groups to undergo the following experiments. One, 2, 3, and 4 weeks later the sensory nerve action potentials (SNAPs) of bilateral medium nerves 5 mm from the anastomotic stoma and the compound muscle action potentials (CMAPs) of bilateral superficial digital flexor muscles were measured with stimulating and recording electrodes. Specimens of the distal part of bilateral medium nerves 5 mm from the anastomotic stoma were collected to calculate the number of modulated fibers by electron microscopy. The tendons of bilateral superior digital flexor muscles were cut ant the wrist, isolated to the terminal points, ligated, and connected to a sensor so as to record the maximum contraction power. The superior digital flexor muscle was completely resected to be weighted. RESULTS: CMAP failed to be recorded 1 week later. The wave amplitude of the nerve at the affected side increased along with time, however, the CMAP wave amplitudes of the affected side were all significantly lower than those of the healthy side (all P < 0.05). The SNAP wave amplitudes of the medium nerve of both sides increased along with the time. The SNAP levels 4 and 8 weeks later of the affected side were both lower than those of the healthy side (both P < 0.05). The number of modulated fibers of the medium nerve increased along with the time, however, the number of the affected side were significantly lower than those of the healthy side (all P < 0.05). Electron microscopy showed degeneration of medulla in bilateral medium nerves 1 week later, and newborn modulated fibers began to be seen since 2 weeks later. However, there were a greater number and more complete structure in the healthy side in comparison with the affected side. The wet weights of bilateral superior digital flexor muscles decreased 2 weeks later and then began to increase gradually. However, the wet weight 4 and 8 weeks later were significantly greater in the healthy side then in the affected side (both P < 0.05). CONCLUSION: Resection of sympathetic nerve is advantageous on nerve regeneration.