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Objective To determine the effects of laser in situ keratomileusis (LASIK) on best-corrected visual acuity (BCVA) and contrast sensitivity. Design Prospective, observational case series. Participants One hundred twelve eyes, in 65 patients with myopia and myopia with astigmatism, who underwent LASIK. Testing and main outcome measures Best-corrected visual acuity using the Snellen visual acuity chart and contrast sensitivity using the CSV 1000 (Vector Vision, Dayton OH) was tested before surgery and 1 week, 1 month, and 3 months after surgery in patients who underwent LASIK. Results Contrast sensitivity was depressed for patient eyes with spherical equivalence (SE) between −1.25 diopters (D) and −13.75 D, at 12 cycles/degree for at least 3 months and at 18 cycles/degree for 1 week after LASIK. For patient eyes with SE between −1.25 D and −6.00 D, contrast sensitivity was depressed only at 12 cycles/degree for at least 3 months after LASIK. For patient eyes with SE between −6.00 D and −13.75 D, contrast sensitivity was depressed at 6, 12, and 18 cycles/degree 1 week after LASIK but returned toward preoperative levels by 1 month after surgery. Despite the slight decreases in contrast sensitivity, all scores were still within the range of normal values except for 12 cycles/degree for 3 months and 18 cycles/degree at 1 week after surgery in the high myopia group. Although highly myopic patients, compared with patients with low myopia, had slightly less BCVA before surgery, both groups maintained their preoperative BCVA at all postoperative visits. Conclusions Based on this study, we conclude that LASIK has little effect on BCVA and contrast sensitivity for up to 3 months after surgery.

Purpose: To determine the population-based incidence and cause of cranial nerve palsies affecting ocular motility in children in the circumscribed population of Olmsted County, Minnesota. MethodsM: The Rochester Epidemiology Project medical records linkage system captures virtually all medical care provided to Olmsted County residents. By means of this database, all cases of third, fourth, and sixth cranial nerve palsy were identified among county residents less than 18 years of age from 1978 through 1992. Medical records were reviewed to confirm the diagnosis, determine the cause, and document county residency. Incidence rates were adjusted to the age and sex distribution of the 1990 white population in the United States. Results: Over this 15-year period, 36 incidence cases of cranial nerve palsy were identified in 35 children in this defined population. The age-adjusted and sex- adjusted annual incidence of third, fourth, and sixth nerve palsies combined was 7.6 per 100,000 (95% confidence interval, 5.1 to 10.1). The most commonly affected nerve was the fourth (36%), followed by the sixth (33%), the third (22%), and multiple nerve palsies (9%). The most common cause was congenital for third and fourth nerve palsy, undetermined for sixth, and trauma for multiple nerve palsies. Although three cases were associated with neoplasia, a cranial nerve palsy was not present at the time of diagnosis in any case. Conclusions: Unlike many institutionally based referral series, our population-based study provides data on the incidence and cause of third, fourth, and sixth nerve palsies in a geographically defined population. In contrast to previous institutionally based series, nearly half the cases were congenital in origin, and in no case did intracranial neoplasia present as an isolated nerve palsy.

Purpose To determine the incidence of sixth nerve palsy in a population-based study, with particular emphasis on associated coexisting medical conditions and to use these data to develop a management algorithm. Design Retrospective, population-based case series. Participants All residents of Olmsted County, Minnesota, USA, diagnosed with sixth nerve palsy between January 1, 1978 and December 31, 1992. Methods All cases were identified by using the Rochester Epidemiology Project medical records linkage system, which captures all patient-physician encounters in Olmsted County. The entire medical record of each patient was reviewed to confirm the diagnosis, document county residency, and to determine associated medical conditions. We used stringent predetermined criteria to define diabetes mellitus and hypertension as associations. Incidence rates were adjusted to the age and gender distribution of the 1990 white population in the United States. Main outcome measures Etiology or systemic associations of the palsy. Results We identified 137 new cases of sixth nerve palsy over the 15-year period. The age- and gender-adjusted annual incidence of sixth nerve palsy was 11.3/100 000 (95% confidence interval, 9.3–13.2/100 000). Causes and associations were: undetermined (26%), hypertension alone (19%), coexistent hypertension and diabetes (12%), trauma (12%), multiple sclerosis (7%), neoplasm (5%), diabetes alone (4%), cerebrovascular accident (4%), postneurosurgery (3%), aneurysm (2%), and other (8%). When sixth nerve palsy was the presenting sign in cases of neoplasm (n = 1) and aneurysm (n = 3), history and examination revealed the presence of other neurologic symptoms or signs. Conclusions We provide population-based data on the incidence of sixth nerve palsy with a notably lower incidence of neoplasm and higher incidence of diabetes and hypertension than previous institution-based series. We suggest that patients with nontraumatic neurologically isolated sixth nerve palsy may undergo a focused medical evaluation followed by close observation, whereas non–neurologically isolated cases warrant a full neurologic evaluation, including prompt neuroimaging.

Purpose To estimate the spontaneous recovery rate of isolated traumatic sixth-nerve palsy. Method A retrospective chart review over a 24-year period at a single institution, excluding patients who were first seen more than 6 weeks after injury, to reduce bias toward nonrecovery. Results The Kaplan-Meier survival estimate of spontaneous recovery at 6 months was 27% (95% confidence interval [CI], 5% to 44%) in unilateral traumatic sixth-nerve palsy and 12% (95% CI, 0% to 33%) in bilateral traumatic sixth-nerve palsy. Conclusion Spontaneous recovery from isolated traumatic sixth-nerve palsy may be lower than previously reported. A prospective study is needed to provide a more accurate estimate of recovery rate.