Background The alteration of dominance eye is associated with visual quality in patients with age-related cataract or after cataract-surgery.However,the study on the relationship of dominance eye shift with vision following cataract-surgery is lack.Objective This study was to observe the influence of age-related cataract and cataract surgery on ocular dominance in the elderly.Methods A serial cases-observational study was designed.Eighty-seven patients with age-related cataract were collected from December 2011 to April 2012 in Affiliated Eye Hospital of Wenzhou Medical University,and phacoemulsification combined with intraocular lens (IOL) implantation was performed in all the patients.The patients were grouped into binocular vision difference (best corrected distance vision) ≥2 lines group (42 patients) and ≤ 1 line group (45 patients) on the standard logarithmic visual acuity chart.The frequency and shift of dominant eye were determined by card-hole method or thumb method before operation and 1 day,1 week,1 month and 3 months after operation.The difference in the frequencies of dominant eye between before and after operation was analyzed with MecNmar test.Results The median of best corrected distance vision (LogMAR) was 0.40 (0.00-1.40) in preoperation and 0.00 (-0.08-0.30) in postoperation,with significant difference between them (Z=-9.481,P =0.000).In the binocular vision difference ≥ 2 lines group,the dominant eyes were 24 in the right eyes and 18 in the left eyes.The milder cataractous eyes were identified as dominant eyes in 33 (78.57％) patients and heavier cataractous eyes were determined as dominant eyes in 9 (21.43％) patients before operation.However,the right eye was evidenced as dominant eye in 31 patients and the left eye was in 11 patients after operation.In the 42 patients,dominant eye shifted from the left eyes to the right eyes in 10 patients and from the right eyes to the left eyes in 3 patients,and 4 patients presented an unstable change binocularly.In 45 patients of the binocular vision difference ≤ 1 line group,the dominant eyes were the right eyes in 27 patients and the left eyes in 18 eyes in preoperation ; while after operation,dominant eye altered form the left eyes to the right eyes in 3 patients and form the right eyes to the left eyes in 1 patient,and unstable change occurred in 5 patients.There were no significant differences in the frequency of dominant eyes between before and after operation both the two groups (group A:P =0.092 ; group B:P =0.727).Conclusions Age-related cataract impact on eye dominance.Dominance eye may occur alteration binocularly following cataract surgery,which is one of causes of visual discomfort.

Objective: To determine the optimal dose of dexmedetomidine required to prevent nausea and vomiting when used for postoperative analgesia after gynecological laparoscopic surgery. Methods: A total of 135 patients, aged 18-60 yr, weighing 52-80 kg, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective gynecological laparoscopic surgery, were divided into 3 groups (n=45 each) using a random number table method: control group (group C), dexmedetomidine 1 μg/kg group (group D₁) and dexmedetomidine 2 μg/kg group (group D₂). Immediately after anesthesia induction, dexmedetomidine 0.4 μg·kg^-1·h^-1 was injected intravenously until 30 min before the end of surgery in all the patients.When the patient was fully awake at the end of surgery, the tracheal tube was removed, and patients were sent to postanesthesia care unit and received patient-controlled intravenous analgesia (PCIA). The PCIA solution contained sufentanil 1.2 μg/kg and dezocine 20 mg in 100 ml of 0.9% normal saline.The PCIA pump was set up with a 0.5 ml bolus dose, a 15 min lockout interval and background infusion at a rate of 2 ml/h.Dexmedetomidine 1 and 2 μg/kg were added to PCIA solution in group D₁ and group D₂, respectively.The occurrence of nausea and vomiting was recorded in postanesthesia care unit stay period (P₁) and in 0-12 h (P₂), 12-24 h (P₃), 24-36 h (P₄) and 36-48 h (P₅) periods after patients returned to the ward.Ramsay sedation score was recorded at 12, 24, 36 and 48 h after patients returned to the ward.When visual analogue scale score >3, patients were told to press PCIA.Patients were followed up for 48 h after surgery, and patients′ satisfaction, pressing times of PCIA and occurrence of pruritus, respiratory depression, bradycardia and dizziness were recorded. Results: Compared with group C, the incidence of nausea was significantly decreased in P₂ period, and the pressing times of PCIA were reduced in P_{2, 3} period in D₁ and D₂ groups (P<0.05). There was no significant difference in Ramsay sedation score at each time point, patients′ satisfaction and incidence of bradycardia among the three groups (P>0.05). No patients developed pruritus, respiratory depression or dizziness in the three groups. Conclusion The optimal dose of dexmedetomidine required to prevent nausea and vomiting is 1 μg/kg when used for postoperative analgesia after gynecological laparoscopic surgery.