Göran Stigmar

OBSERVATIONS ON VERNIER AND STEREO ACUITY WITH SPECIAL REFERENCE TO THEIR RELATIONSHIP

The vernier and stereo visual functions are in many respects very closely connected as noted by many authors (Linksz 1952, Ludnigh 1953, Le Grand 1956, and others). Both are said to be based on the perception of relative direction differences (Ludwigh 1953). Vernier acuity (nonius acuity or aligning power) is the ability to detect a break in a contour or irregularity in a line. As pointed out by Ludwigh & Bair (1953) a distinction must be made between the perception of relative direction differences in a vernier or a stereoscopic situation and the perception of the absolute location of an object in space, a fact which makes the traditional terms “direction (or localization) sense of the eye” inappropiate names for this capacity of the visual system. Stereoscopic vision is in this investigation only studied within the limited range of binocular vision, which Ogle (1952) has defined as the region of “patent stereopsis”. The stereoscopic acuity in this range has an accuracy comparable with the vernier acuity. I t has been almost generally accepted that the disparity (transverse disparity) between the retinal images is the only stimulus necessary to release the perception of stereopsis. This conception was stressed not least by Ogle (1959).

Retinopathy of prematurity in the southern part of Sweden.

Abstract. The incidence of retinopathy of prematurity (ROP) was studied in prematures in the southern part of Sweden during one year. Nine hospitals participated in the prospective study. During the period 23 745 children were born in the region. One hundred and ninety‐three of 214 prematures of gestational age ≤32 weeks and/or birth weight ≤ 1500 g, were subjected to ophthalmic investigation. The incidence of ROP among the prematures under study was calculated to 9% (17 children). Six of them had severe ROP (3%). Some risk factors associated to ROP are discussed.

Anorexia nervosa associated with cataract. (Report of a case).

The patient was a 30-year-old dental mechanic. In 1958 she married but because of her husbands abuse of alcohol there was a divorcement in 1962. There is no family history of cataract. Physically the patient developed normally during childhood and adolescence. Prior to that time she allegedly had had no difficulty with her vision. Shortly after her marriage her menses became irregular, scanty, and farther apart until amenorrhea began one year later. At this time she began to lose weight gradually and in the next 3 years she lost 28 kg. During this period her vision began to fail. When examined in 1959 she had a corrected visual acuity of 0,7 0. D. and 0,5 0. S. The eyes were pale, there was no signs of intraocular inflammation. Slit lamp examination revealed bilateral posterior subcapsular lens opacities bilaterally. The fundi were normal. The opacities increased with progressive visual loss and she was admitted to an ophthalmological department, 1960. At that time visual acuity was 0,2 bilaterally. Slit-lamp examination now revealed a dense irregular posterior cataract. A capsular discision followed by evacuation was performed on the left eye. The final visual acuity of 1,0 with a + 11 sphere. In 1962 a capsular discision was performed on the

TESTING FOR HYPERMETROPIA IN THE SCHOOL VISION SCREENING PROGRAMME

The need and accuracy of a hypermetropia test, recommended as a screening test in Swedish schools, was evaluated in a series of 118 8‐year‐old children not wearing glasses. The distant visual acuity was determined without correction and with plus spheres of two different strengths, +1.5 D and +2.0 D respectively. When compared to the objective refraction and with an arbitrary limit of hypermetropia of +2.5 diopters, it could be shown that neither of the hypermetropia tests fulfilled the criteria of an adequate screening test. Except for two children all hypermetropics beyond +3.0 were previously known. The reading skills of the children were estimated by their teachers. No correlation was found between the degree of hypermetropia and reading difficulties. The results indicate that the hypermetropia test could be omitted from the regular vision tests of schoolchildren, at least in areas covered with an efficient pre‐school vision screening.

Effect of some pituitary preparations on the normal flare density in rabbits' eyes.

ACTH belongs to a group of substances whose activity has proved useful in the treatment of inflammatory states of the eye. Effects on the intraocular pressure have also been recorded on clinical material; these reports are, however, by no means unequivocal. Both an increase of pressure and a regulation of an increased pressure in cases of uveitis have been described. According to Tillet ACTH has no effect on the i. 0. p. in normal human eyes (1952). The existence of factors other than ACTH in the pituitary which influence the i. 0. p. has been anticipated by several authors (a. 0. Schinerl 1956). During the last years 24 hours rhythms have been observed in the flow of aqueous in man (Ericson 1958) and in the flare density, i. e. the protein content of the aqueous (Anjou 1961, man, rabbit). The relationships between the activity of the endocrine system, which has also a 24-hour trend, and the diurnal variations in aqueous dynamics have been established by Linngr (1959). These facts formed the reason for some preliminary studies on the activity of ACTH and cortisone on the flare density (Anjou & Kraknu 1961, Anjou 1961). In the present investigation on rabbits the effect on the aqueous flare of a commercial ACTH preparation (,,Acton<<@), two purified ACTH preparations and a commercial, chromatographically pure vasopressin preparation (,,Postacton<<@) have been studied. In the >>Acton<< series also the i. 0. p. has been followed.

Orbital mass in a child causing somnolence, nausea and bradycardia

PurposeTo highlight the need for referral and prompt intervention when signs of increased intraorbital pressure are present.Clinical featuresA four year old child presented to hospital with orbital swelling of recent onset, nausea and somnolence. Computed tomography and brain scan demonstrated a normal brain with a mass in the left orbit. She was referred for ophthalmic surgery the following day, when she had lost responsiveness of her left pupil to light. Anaesthetic management was highlighted by the presence of preoperative signs and symptoms of increased intraocular pressure — somnolence, nausea and vomiting, and bradycardia. These signs and symptoms were alleviated postoperatively.ConclusionRapid onset of orbital swelling with physiological signs of increased orbital pressure necessitate urgent surgical intervention. It is possible that early referral and surgery could have preserved some functional vision in a situation where the light reflex remained in the affected eye. Alleviation of preoperative nausea and vomiting, bradycardia, and somnolence indicates that the preoperative symptomatology was related to vagal stimulation from increased intraocular pressure, usually identified as an oculocardiac reflex.RésuméObjectifSouligner la nécessité d’une intervention spécialisée et rapide lorsque des signes d’accroissement de la pression intra-orbiraire sont présents.Aspects cliniquesUne enfant de quatre ans s’est présentée à l’hôpital souffrant d’un œdème orbitaire d’apparition récente, de nausées et de somnolence. La tomodensitométrie et la scintigraphie cérébrale ont montré un cerveau normal, mais une masse dans l’orbite gauche. La fillette a été dirigée en chirurgie ophtalmique le lendemain, alors que sa pupille gauche ne réagissait plus à la lumière. Les modalités de l’anesthésie ont été dictées par la présence des signes et des symptômes préopératoires de l’accroissement de la pression intraoculaire: somnolence, nausées, vomissements et bradycardie. Ces signes et symptômes se sont atténués après l’intervention.ConclusionLe début rapide de l’œdème orbitaire accompagné des signes physiologiques de l’augmentation de pression intraoculaire nécessitent une chirurgie d’urgence. Il est possible que l’examen spécialisé et la chirurgie précoces aient pu préserver, en partie, la vision fonctionnelle dans des circonstances où le réflexe pupillaire était conservé dans l’oeil touché. Le soulagement des nausées, des vomissements, de la bradycardie et de la somnolence préopératoires indique que la symptomatologie était reliée à une stimulation vagale provenant de la pression intraoculaire accrue, habituellement identifiée comme étant un réflexe oculocardiaque.

VISUAL ACUITY WITH BRIEF STIMULI

Vernier acuity, stereoscopic acuity and resolving power (“resolution”) have been determined for eight different exposure times, ranging from 4 sec to 0.025 sec, at two levels of luminance with a technique which permits examination under identical conditions for the three visual functions. The results of this study can be summarized as follows.

A novel surgical technique employing donor sclera in strabismus surgery

We describe a novel surgical technique employing donor sclera as a spacer to solve the problem encountered in complicated cases of restrictive strabismus surgery when no more muscle or tendon is available for surgical extension of the eye muscle to correct the angle of deviation. This is often the case in patients who have previously undergone extensive surgery and in patients with mechanical restrictions, such as thyroid-associated orbitopathy (TAO).