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PubMedDate not supplied

Development of melanosomes and cytochemical observation of tyrosinase activity in the inner ear.

The ultrastructure and tyrosinase activity of melanocytes in the inner ear of pigmented guinea pigs were observed. Melanocytes/melanocyte-like cells were seen in the stria vascularis, the vestibular dark cell area and the endolymphatic sac. In the stria vascularis, melanosomes in several stages of maturation were seen in the cytoplasm of the intermediate cells and melanin-laden endosomes existed in the basal cells. Only the intermediate cells contained tyrosinase-positive cytoorganelles; Golgi sacs and neighboring small vesicles. Numerous melanocytes containing many melanosomes were observed under the epithelium of the vestibular dark cell area, and they showed tyrosinase activity. Melanocytes were seen in the endolymphatic sac, and they also showed tyrosinase activity. However, the epithelial cells of the endolymphatic sac, which had vacuoles containing melanin, did not show tyrosinase activity. Based on these findings, it can be said that (1) most of the intermediate cells of the stria vascularis must be melanocytes, (2) melanogenesis is vigorous in melanocytes of the inner ear, and (3) melanin in the epithelial cells of the endolymphatic sac is transferred in from melanocytes and is never synthesized in the epithelial cells.

Animals↗
PubMed1984

Eye-head coordination in cats.

Gaze is the position of the visual axis in space and is the sum of the eye movement relative to the head plus head movement relative to space. In monkeys, a gaze shift is programmed with a single saccade that will, by itself, take the eye to a target, irrespective of whether the head moves. If the head turns simultaneously, the saccade is correctly reduced in size (to prevent gaze overshoot) by the vestibuloocular reflex (VOR). Cats have an oculomotor range (OMR) of only about +/- 25 degrees, but their field of view extends to about +/- 70 degrees. The use of the monkey's motor strategy to acquire targets lying beyond +/- 25 degrees requires the programming of saccades that cannot be physically made. We have studied, in cats, rapid horizontal gaze shifts to visual targets within and beyond the OMR. Heads were either totally unrestrained or attached to an apparatus that permitted short unexpected perturbations of the head trajectory. Qualitatively, similar rapid gaze shifts of all sizes up to at least 70 degrees could be accomplished with the classic single-eye saccade and a saccade-like head movement. For gaze shifts greater than 30 degrees, this classic pattern frequently was not observed, and gaze shifts were accomplished with a series of rapid eye movements whose time separation decreased, frequently until they blended into each other, as head velocity increased. Between discrete rapid eye movements, gaze continued in constant velocity ramps, controlled by signals added to the VOR-induced compensatory phase that followed a saccade. When the head was braked just prior to its onset in a 10 degrees gaze shift, the eye attained the target. This motor strategy is the same as that reported for monkeys. However, for larger target eccentricities (e.g., 50 degrees), the gaze shift was interrupted by the brake and the average saccade amplitude was 12-15 degrees, well short of the target and the OMR. Gaze shifts were completed by vestibularly driven eye movements when the head was released. Braking the head during either quick phases driven by passive head displacements or visually triggered saccades resulted in an acceleration of the eye, thereby implying interaction between the VOR and these rapid-eye-movement signals. Head movements possessed a characteristic but task-dependent relationship between maximum velocity and amplitude. Head movements terminated with the head on target. The eye saccade usually lagged the head displacement.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Stereociliary myosin-1c receptors are sensitive to calcium chelation and absent from cadherin 23 mutant mice.

The identities of some of the constituents of the hair-cell transduction apparatus have been elucidated only recently. The molecular motor myosin-1c (Myo1c) functions in adaptation of the hair-cell response to sustained mechanical stimuli and is therefore an integral part of the transduction complex. Recent data indicate that Myo1c interacts in vitro with two other molecules proposed to be important for transduction: cadherin 23 (Cdh23), a candidate for the stereociliary tip link, and phosphatidylinositol 4,5-bisphosphate (PIP2), which is abundant in the membranes of hair-cell stereocilia. It is not known, however, whether these interactions occur in hair cells. Using an in situ binding assay on saccular hair cells, we demonstrated previously that Myo1c interacts with molecules at stereociliary tips, the site of transduction, through sequences contained within its calmodulin (CaM)-binding neck domain, which can bind up to four CaM molecules. In the current study, we identify the second CaM-binding IQ domain as a region of Myo1c that mediates CaM-sensitive binding to stereociliary tips and to PIP2 immobilized on a solid support. Binding of Myo1c to stereociliary tips of cochlear and vestibular hair cells is disrupted by treatments that break tip links. In addition, Myo1c does not bind to stereocilia from mice whose hair cells lack Cdh23 protein despite the presence of PIP2 in the stereociliary membranes. Collectively, our data suggest that Myo1c and Cdh23 interact at the tips of hair-cell stereocilia and that this interaction is modulated by CaM.

Animals↗
PubMed1980

Relationship between the head's and the body's center of gravity during normal standing.

An apparatus for the recording of head movements has been developed and a basic study was performed to determine the normal values of head movement and to estimate the significance of the head movement as a righting reflex. The locus traced by the head closely resembled that of the center of gravity, though shorter in overall length. The head also moves more slowly than the center of gravity. The phase delay of its movement was observed during standing with eyes closed. These results suggest that the head's movement is controlled by the body's center of gravity and that the latter moves in order to keep the head steady, maintaining the eyes in normal position.

Adolescent↗
PubMed1986

Apparatus for measurement of dynamic body equilibrium in the guinea pig.

An apparatus for the measurement of dynamic bodily equilibrium function in guinea pigs was made and its applicability was investigated. This apparatus consists of two cubical boxes (one of them is the starting box, and the other the goal box) connected by a 30 cm wide, 150 cm long, and 20 cm high straight platform. From the grids mounted on the floor of the starting box, an electric stimulation was given to make them run fully on the platform toward the goal box. On the floor of the platform, except for the 7 cm wide center line, 6 channels (3 channels on each side) of pressor-sensor-type recording system are installed. Thus, the animal's running performance is recorded by multi-channel pen recorder. At first, the animals should be screened and trained. Mostly the animals have learned to run with minimal deviations in several tens of training runnings. Thus, when the training period was over, five animals were selected to determine the recovery process of locomotion after the unilateral labyrinthectomy. The obtained results depicted through the gradual decrement of deviation count and running time were consistent with the previously reported results using other animals. Therefore, it could be concluded that this recovery process of bodily dysequilibrium measured by this test procedure must reflect the vestibular compensation of this animal.

Animals↗
PubMed1995

Morphological features of different regions in frog crista ampullaris (Rana esculenta).

The cellular organization of different regions of the crista epithelium from the frog posterior semicircular canal was studied by light, transmission and scanning microscopy. The sensory epithelium consists of hair cells surrounded by supporting cells and basal cells located close to the basement membrane. Three types of hair cells, namely club-like, cylindrical and pear-like cells differentially distributed along the crista could be recognized on the basis of their shape. Club-like cells are located only in the peripheral regions, cylindrical cells both in the central and in the peripheral regions, and pear-like cells appear segregated into the intermediate regions. Sensory cells of the central region are characterized by a ciliary apparatus consisting of stereocilia usually shorter--and in some cases less numerous--than those of cells of the other regions. The presence of large evaginations of the apical membrane of hair cells and of several vesicles of microexocytosis demonstrates that receptor cells have a considerable secretory activity. This secretory activity is also proven by the presence in the supranuclear region of hair cells of numerous Golgi complexes. Moreover, the presence of two kinds of Golgi complexes, one constituted by dilated cisternae containing a moderately electron-dense material and the other made up of flattened electron-transparent cisternae, suggests a diversified secretion of material by the hair cells. This heterogeneous material may provide substances important for cupula formation and the composition of the endolymph.

Animals↗
PubMed1978

Ultrastructural features of spiral ganglion cells. A study of patients with hearing loss of varying origins.

Fresh specimens of the acoustic nerve that were obtained during vestibular neurectomy or acoustic neuroma removal were studied for structure of the spiral ganglion cells. These were large, round or oval cells with many cytoplasmic organelles and were surrounded by Schwann cells. Schwann cells formed a single layer or perikaryal sheath and the cells were thus unmyelinated. In one case the specimen contained part of the spiral ganglion, but in six others spiral ganglion cells were found outside of Rosenthal's canal, among the myelinated nerve fibers. In three cases the ear was deaf due to cochlear insult, but the nerve fibers and ganglion cells showed no retrograde degeneration. The neurophysiologic features of the cochlear nerve should be considered because unmyelinated ganglion cells may have a different conduction capacity in comparison with thickly myelinated cells.

Adult↗
PubMed1996

Alcohol and workload as factors affecting the detection of angular acceleration.

INTRODUCTION: Previous findings have demonstrated that a low blood alcohol concentration (BAC) decreases subjects' ability to detect changes in angular motion and that this effect persists after the BAC returns to zero. METHODS: Angular motion thresholds of six alcohol and six placebo subjects holding pilots' certificates were obtained under both low and high task load conditions. The alcohol subjects were tested under double blind conditions in an enclosed simulator apparatus prior to drinking, after drinking (mean BAC = 0.038%), and at a time when the alcohol subjects' BACs had reached zero. RESULTS: Alcohol subjects' mean threshold values for the three threshold test sessions were 0.361, 0.512, and 0.465 degree.s-2 and 0.292, 0.422, and 0.379 degree.s-2 for the high and low task conditions, respectively. Corresponding values for placebo subjects were 0.364, 0.37, and 0.356 degree.s-2 for the high task load condition and 0.311, 0.317, and 0.312 degree.s-2 for the low task load condition. Statistical analyses showed significant task load and sessions effects (p < 0.025). Significant alcohol by test sessions interactions were found for both high and low task load conditions (p < 0.01) with subsequent t-tests showing no alcohol-placebo differences for the pre-alcohol test session, but significant alcohol-placebo differences for the alcohol test session and the test session conducted after the subjects' BACs returned to zero. CONCLUSIONS: The results indicate that the increased threshold for detecting changes in angular motion found after alcohol ingestion is relatively insensitive to task workload and, thus, it is unlikely that attentional changes underlie the threshold increase. These data together with the finding that an elevated threshold can persist after BAC reaches zero suggest that the threshold increase after alcohol ingestion reflects changes in vestibular functioning.

Acceleration↗
PubMed1982

A multiple choice apparatus for electrophysiological investigations of spatial working memory in rats.

A multiple choice apparatus, minimizing the rat's movements and thus simplifying brain stimulation and/or recording in working memory experiments, consists of a dodecagonal enclosure (30 cm diameter, 100 cm high) with a horizontal platform assuming either an upper or a lower position, 43 or 65 cm below the top of the wall, respectively. The platform is moved between these two levels by a pneumatic system controlled by solid-state programming circuits. Each wall segment contains a choice window, 7 cm above the upper floor level, providing access to a recessed feeder. When the platform with a food-deprived rat moves into the upper position, the animal opens the hinged shutter of one window and gets the pellet. Five seconds later, a self-locking relay marks the visited window and the floor descends to the low position where it remains for a predetermined interval (e.g. 20 s), until it is raised again. The above cycle repeats as a long as different windows are chosen. When a choice is directed to an already visited window (error), the floor returns to the low position at once. During one trial, the animal is allowed 12 choices and the number of errors (i.e. choices directed to already entered windows) is recorded. In spite of the great reduction of kinaesthetic and vestibular signals and the almost complete elimination of visual extramaze cues, the working memory performance is similar to that in analogous radial maze.

Animals↗
PubMed1994

Granular layer collaterals of the unipolar brush cell axon display rosette-like excrescences. A Golgi study in the rat cerebellar cortex.

The unipolar brush cell (UBC) is a medium-sized neuron located in the granular layer of the cerebellar cortex and morphologically characterized by a single dendritic shaft terminated by a brush-like tuft [Mugnaini and Floris, J. Comp. Neurol., in press]. This neuronal class is mostly encountered in the vestibular part of the cerebellum, although also present in the rest of the vermal folia. The UBC axon, as seen in Golgi impregnated material, has a tortuous course throughout the granular layer and gives off number of collaterals of variable diameter. Some of the axon collaterals enter the white matter only for a short distance, after which they ascend into the granular layer. Astonishingly, some of the thick granular collaterals of these axons display characteristic expansions resembling the rosette excrescences seen on mossy fibers. In our series these rosettes are mostly of the simple type [Palay, S. and Chan-Palay, V., Cerebellar Cortex. Cytology and Organization, Springer, Berlin, 1974], i.e. short swellings with simple globular contours. The exact projection targets and functional effect of the UBC axon and granular rosettes have still to be demonstrated.

Animals↗
PubMed1991

The nasal apparatus of the red squirrel (Sciurus vulgaris L.) embryo at the stage of the fully formed chondrocranium.

The nasal apparatus of the squirrel embryo at the optimum stage of the chondrocranium displays simple (though not always primitive) features and individual structures developed largely as in other rodents and even in insectivores. Primitive features include the presence of a cartilago paraseptalis communis and probably the simplicity of the olfactory labyrinth, whose main support in the region as a whole is ethmoturbinale I, whose dorsal and ventral lamella divide off the basic recesses; anterior (frontalis), maxillaris and frontoturbinalis. Completely caudally we find ethmoturbinale I, the frontoturbinalia and the relevant secondary (greatly reduced) recesses. The zona annularis is interrupted by failure of the rostral processes of the lamina transversalis anterior (corresponding to the processes laterales ventrales) to fuse with the capsula nasi ant. or with the anlage of the septum nasi. We did find a fenestra nasi superior (lateralis). The atrioturbinale is well developed, the maxilloturbinale only as a trace, but we have a very striking nasoturbinale. In the rostral region of the olfactory segment, the cartilaginous capsule has a very conspicuous thickening, which in this part is formed of paranasal cartilage. The thickening presents outwardly as the prominentia anterior; cavity of the recessus anterior (frontalis) is formed inside it. The rest of the dorsal and caudal wall of this cavity forms the crista semicircularis, which further caudally circumscribes the foramen olfactorium. A foramen epiphaniale is present. The vestibular region of the epithelial nasal tube is interestingly formed. In cross section it is crescent-shaped; the nasal tube itself opens into the convexity, but the lamina transversalis ant. sends a turbinale into the concavity. A cartilago alaris superior, which develops independently in situ, is present; in our stage it is associated with the wall of the capsule, but ventrolaterally it terminates freely and is not joined to any other element. The morphological interpretation of particular elements is discussed.

Animals↗
PubMed1977

A closed-flow water caloric system.

This paper describes a new method and apparatus to induce nystagmus. Flow of fluid into the ear to induce nystagmus is eliminated by utilization of a closed-flow system. A probe adapted for insertion to a standardized depth into the ear, provides a flow-through path for nystagmus-inducing liquid while expanding in response to the pressurized liquid to conform to the contours of the external auditory canal and tympanic membrane. Thermal conductivity through the membrane-like probe material permits heat exchange between the flowing liquid, and the external auditory canal and/or tympanic membrane to induce nystagmus.At this time, the authors can state only that the quality of nystagmus produced is similar to that produced by current conventional methods. In the small number of patients tested, discomfort appeared to be almost negligible. The system appears to be a promising improvement dependent on the establishment of accurate parameters for diagnosis.

Caloric Tests↗
PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗
PubMed2002

Effects of predictive mechanisms on head stability during forward trunk perturbation.

While much is known about reflex and mechanical contributions to the control of head stability, little is known about predictive control. The goal of this experiment was to determine the contribution of predictive mechanisms to head stability in space, in the pitch plane, during forward trunk perturbations. Eleven standing healthy subjects had their trunk pulled forward by a load-pulley apparatus. The perturbation was either self-triggered or imposed (triggered by the experimenter). Subjects were exposed to two loads: 2% and 4% of their body weight. The contributions of torques acting on the head-neck system were inferred from head and trunk kinematics, neck muscle EMG, and the torques acting on the head, which were computed using inverse dynamics. The results showed that both the head and trunk moved less during the self-triggered than imposed condition during both loads for most of the participants. There was no evidence of predictive neck countertorque or increased neck muscle co-contraction during the self-triggered condition. These findings suggest that most of the subjects improved head stability in the self-triggered condition by reducing trunk motion and the associated interactive torque that perturbed the head.

Adaptation, Physiological↗
PubMed2006

Latency and initiation of the human vestibuloocular reflex to pulsed galvanic stimulation.

Cathodal galvanic currents activate primary vestibular afferents, whereas anodal currents inhibit them. Pulsed galvanic vestibular stimulation (GVS) was used to determine the latency and initiation of the human vestibuloocular reflex. Three-dimensional galvanic vestibuloocular reflex (g-VOR) was recorded with binocular dual-search coils in response to a bilateral bipolar 100-ms rectangular pulse of current at 0.9 (near-threshold), 2.5, 5.0, 7.5, and 10.0 mA in 11 normal subjects. The g-VOR consisted of three components: conjugate torsional eye rotation away from cathode toward anode; vertical divergence (skew deviation) with hypertropia of the eye on the cathodal and hypotropia of the eye on the anodal sides; and conjugate horizontal eye rotation away from cathode toward anode. The g-VOR was repeatable across all subjects, its magnitude a linear function of the current intensity, its latency about 9.0 ms with GVS of >or=2.5 mA, and was not suppressed by visual fixation. At 10-mA stimulation, the g-VOR [x, y, z] on the cathodal side was [0.77 +/- 0.10, -0.05 +/- 0.05, -0.18 +/- 0.06 degrees ] (mean +/- 95% confidence intervals) and on the anodal side was [0.79 +/- 0.10, 0.16 +/- 0.05, -0.19 +/- 0.06 degrees ], with a vertical divergence of 0.20 degrees . Although the horizontal g-VOR could have arisen from activation of the horizontal semicircular canal afferents, the vertical-torsional g-VOR resembled the vestibuloocular reflex in response to roll-plane head rotation about an Earth-horizontal axis and might be a result of both vertical semicircular canal and otolith afferent activations. Pulsed GVS is a promising technique to investigate latency and initiation of the human vestibuloocular reflex because it does not require a large mechanical apparatus nor does it pose problems of head inertia or slippage.

Adult↗
PubMed1978

[Cortical localizations seen by the dynamic gamma-camera : a new approach in neuropsychology].

We present here the results obtained in the study of normal brain functions, in normal awake man performing normal voluntary tasks, by mean of new approach developed in our laboratory. Its principle lies on the fact that focal changes in cortical blood flow during brain function are due to the coupling between local function aand metabolism, which has been demonstrated in man during hand movement by Olesen (1971) and by Raichle and associates (1976). So far as the changes are focal (uni- or multifocal) they can be assessed by external measurement of focal cerebral blood flow (rCBF) with the 133Xenon clearance technique, provided that the detection apparatus used yields a proper spatial and temporal resolution. A temporal resolution of 45 sec. is made possible by the initial slope calculation of Olesen and coll. (1971), using intracarotid injection of isotope. The spatial resolution has been improved by the design of a special system using 254 scintillation detectors with individual collimation, each 8 mm ø, connected to individual ratemeters (Sveinsdottir et al., 1975). This allows the simultaneous processing of the 254 clearance curves by a small on-line Varian computer. The results are displayed as functional colour pictures of the brain on a T.B. screen, less than 3 min. after isotope injection. The studies have been performed to date in more than 200 patients, usually in connection with carotid angiography. 84 subjects could be classified as "normals+ because of lack of detectable brain lesion and of permanent symptoms, and they constitute the reference material for exploring normal brain functions. In each case one or two "rest" studies have been made for comparison with the test situations. The following observations were made: Resting pattern: with the patients lying in a quiet dark room with minimal sensory input the normal pattern is much the same in both hemispheres and it is characterized by higher flows in the anterior upper parts of the frontal lobes (fig. 1 a). The percent variation in a given area during two different rest studies is about 5 percent (fig. 1 b). Primary sensory inputs. Auditory and visual inputs activate the corresponding parts of temporal and occipital regions (fig. 2 and 3). Simple cutaneous stimulation such as touch or vibrations do not change the rest pattern. Moderate pain gives a global increase of CBF, pre-dominantly in the frontal regions (Ingvar, 1976). Vestibular stimulation with cold or warm water in the ear gives an increase of rCBF in the parietal regions. Simple movements. Movements of mouth, eyes, hand or foot clearly activate the corresponding parts of the central region, with an increase of rCBF up to 50--100% (Sveinsdottir et al., 1975). When the movement is repetitive there is in all cases an additional clearcut increase in the upper premotor region, probably including the supplementary motor area. This last region is activated alone when the subject tries to imagine a movement without actually moving (fig. 5 a, b, c). Sensory discrimination...

Acoustic Stimulation↗
PubMed1977

Quantitative electron microscopic analysis of the epithelium of normal human alveolar mucosa.

The epithelium of normal human alveolar mucosa originating from the anterior vestibulum was subjected to stereologic analysis. Eight biopsies were collected half-way between the muco gingival junction and the vestibular fornix from 20 to 50 year-old females, and processed for light and electron microscopy. At two levels of magnification, electron micrographs were sampled from four artificially selected strata in regions of epithelial ridges. Stereologic point counting based on a computer-aided system for analyzing stratified epithelia served for examining a total of about 860 electron micrographs. The alveolar epithelium was 0.26 mm thick, occasionally interdigitated by short, slender connective tissue papillae, and consisted of (1) a narrow basal and suprabasal, and (2) a broad spinous and surface compartment. It displayed a differentiation pattern which, in most subjects studied, was similar to that of normal human buccal epithelium, however, on the average, produced less mature surface cells. This pattern was expressed mainly by a density increase of cytoplasmic filaments (98 A in diameter), a concomitant decrease of the cytoplasmic ground substance, the formation of dark-cored membrane coating granules, and invividually variable amounts of glycogen deposition. In some subjects, a mixed differentiation pattern was found. The structural organization of alveolar epithelium, in analogy to cheek epithelium, was compatible with the function of distensibility.

Adult↗
PubMed1997

[What is the role of contact lenses within the scope of electronystagmography?].

BACKGROUND: During electronystagmography it is necessary to correct detective vision for calibration, smooth pursuit, and saccadic eye movements. Therefore more and more people use contact lenses instead of normal glasses. Given the lack of detailed information about this phenomenon, in the current literature we decided to investigate the influence of soft contact lenses on electronystagmography. The aim of this study was to find out differences in the results of electronystagmography between using glasses or contact lenses. METHODS: Our investigation involved 20 vestibular healthy human subjects with myopia. In the first part of the examination they used their contact lenses and in the second part they were wearing normal glasses. After measuring the calibration potential we wanted to see if contact lenses would increase the rate of artifacts in the electronystagmogram. Then we attempted to determine whether contact lenses would an influence on the registration of the optokinetic nystagmus. Induced saccadic eye movements were recorded and analysed. RESULTS: Contact lenses had a negative influence neither on the calibration potential nor on the rate of artifacts. The latency of the saccadic eye movements also showed no differences between both parts of this investigation. Only the velocity of the saccades and the gain value during the optokinetic test were reduced when glasses were used. CONCLUSIONS: Contact lenses may stimulate the secretory function of the lacrimal gland and thus decrease friction forces. It is also possible that the reduced image size produced or the reduction-effect of minus by glasses in near sighted persons negatively influences eyeball velocity. In summary, our study demonstrates that contact lenses do not have a negative influence on electronystagmography. Therefore electronystagmographic studies of patients with contact lenses are permissible for purposes of documenting a medical opinion.

Adult↗