[Morphoscopic perception at variable contrast and luminance levels in 97 subjects]. / Le sens morphoscopique à contraste et luminance variables chez 97 appelés du contingent.

BACKGROUND: Morphoscopic perception at variable contrast and luminance levels has been assessed in various diseases and in occupational medicine. To our knowledge, this function has not been studied in young adults of similar age. We performed a prospective study to assess morphoscopic perception at variable contrast and luminance levels in a group of young servicemen. METHODS: A total of 97 subjects (194 eyes) with a mean age of 22.4 (standard deviation 1.16) years were assessed with the Gradual monitor. After visual acuity was measured, morphoscopic perception was assessed at a mean light level of 85 cd/m2, at low, medium and high spatial frequencies, with myopic correction. All subjects whose visual acuity was not correctable to 10/10 in both eyes or whose score was statistically too different from the mean underwent a complete ophthalmologic examination. RESULTS: Overall, 87 subjects had a visual acuity correctable to 10/10 or better in both eyes. For 34 of the 87, at least one of the six scores was more than 1 standard deviation below the mean; however, for 16 subjects the result was within normal limits after minor adjustment of the correction, often of a small degree of astigmatism. Of the 18 remaining subjects 7 had microstrabismus, 8 had anatomic lesions and 3 had lesions of unknown origin. Of the 13 subjects with a visual acuity of less than 10/10, 5 had relative amblyopia, 2 had major ametropia, 2 had unilateral and 2 bilateral ophthalmologic lesions, and 2 had reduced acuity of unknown cause. INTERPRETATION: In this young population the most frequent cause of reduced contrast sensitivity (40%) was associated with minor uncorrected or badly corrected refractive problems. The next most frequent cause was problems with binocular vision, with or without amblyopia (11%). In these subjects contrast sensitivity was reduced in the nondominant eye and, in five cases, in the dominant eye also.

[Comparison between Greenbaum's parabulbar anesthesia and Ripart's subtenon anesthesia in the anterior segment surgery]. / Comparaison de l'anesthésie parabulbaire selon Greenbaum et l'anesthésie sous-ténonienne de Ripart dans la chirurgie du segment antérieur.

PURPOSE: To compare two methods of sub-tenon anesthesia in 80 surgical procedures (phakoemulsification, glaucoma and combined surgery) in a prospective, single-surgeon study. MATERIALS AND METHODS: Forty patients requiring anterior segment surgery in each eye were randomised to receive subtenon anaesthesia by either Greenbaum's method (using a flexible plastic cannula) or Ripart's method (using a 23G hypodermic needle). Randomization dictated the mode of anaesthesia for the first eye, the other technique being used for the second eye. Anaesthesia consisted of 1.5ml lidocaïne 2% and 1.5ml bupivacaïne 0.5% in all cases, and was performed by the same surgeon (EDLM) immediately before surgery. Type of surgical procedure, duration, complications, presence of sub-conjunctival haemorrhage, were assessed by the surgeon, who also graded chemosis (0-3), nuclear hardness (1-4), and ocular akinesia (0-2) for each patient. Pain was scored subjectively by each patient (0-10) during the injection, peroperatively and postoperatively. RESULTS: Chemosis was significatively higher with Greenbaum's method than Ripart's method (p<0.01) and was sometimes undesirable for the surgeon. There was no difference in the pain score during the injection, preoperatively or postoperatively. Pain was usually very light and did not correlate with the duration of surgery. There was no akinesia in the majority of cases with either method, but the surgeon was sometimes limited by the akinesia of the medial rectus muscle and often by that of the inferior rectus muscle with elevation of the globe. CONCLUSION: Greenbaum's method and Ripart's method are two subtenon anesthesic techniques characterized by an immediate, intense and prolonged analgesia (sometimes 60mn). Complete akinesia is rare and this is sometimes limiting. Chemosis was more often associated with Greenbaum's method, but Ripart's method carries the potential for needle-related complications.