Joseph H. Maino

Eccentricity perception in the periphery of normal observers and those with retinitis pigmentosa

ABSTRACT The perception of the eccentricity of a suprathreshold light flash (III/4e) presented in a Goldmann perimeter was measured in four ophthalmologically normal observers and three young observers with retinitis pigmentosa (RP). The task was to indicate the perceived distance from central fixation of each light flash by making a mark on a 180‐mm line drawn on a sheet of paper. In the center of the line was a hash mark. Observers were instructed that the hash mark should correspond to fixation and the ends of the line to the limits of the visual field. The vertical, horizontal, and both 45° oblique meridians were tested. The results showed that: 1. The extent of the field along the tested meridian determined perceived eccentricity, i.e., eccentricity of 45° in the temporal field of normals was perceived as equally eccentric as 30° in the superior field. 2. The central 20° were taken to represent more of the perceptual field than any other 20°. 3. Along a meridian, the eccentricity which extends from fixation to 16% of the way to the field limit along the meridian is perceived as extending to 25% of the field by normal observers. 4. On the other hand, observers with RP reported that along a meridian the eccentricity extending from fixation to 8% of the field limit is perceived as extending to 25% of the field. Kinetic primary with the II/4 target showed no evidence of field constriction in observers with RP. However, losses in sensitivity are evident starting at about 10°. Full field single flash electroretinograms were unrecordable in the observers with RP. The data were interpreted to reveal a perceptual magnification of the central field in the relatively early stages of RP.

Distortion and Size Calibration of the Scanning Laser Ophthalmoscope (slo) Laser-beam Raster

Purpose. The Rodenstock scanning laser ophthalmoscope (SLO) is useful for mapping retinal function and for developing and evaluating visual rehabilitation methods. It is essential to know the visual angle subtended by stimuli in the SLO laser-beam raster and to accurately measure angular distances between objects in the final SLO image. To accomplish this, the angular extent of the SLO laser-beam raster must be calibrated. Methods. We developed a simple method and apparatus for calibrating the raster and used it for repeated calibrations during a 3-month period. Results. The laser-beam raster is quite stable in shape and size, but it is trapezoidally distorted in the vertical direction. Consequently, SLO images are distorted. Conclusions. Trapezoidal distortion of the SLO laser-beam raster can cause stimulus size to change as much as 10% from the top to the bottom of the raster. Measurements of fixed horizontal retinal landmark distances in SLO images can also vary as much as 10%. We developed a straightforward mathematical method for correcting distortion in SLO image measurements.

Retinal image location of hand, fingers, and objects during manual tasks.

Purpose. A new method was developed using the scanning laser ophthalmoscope (SLO) to investigate the effects of central visual loss on eye-hand coordination in manual tasks. Using the SLO, the retinal positions of the hand, fingers, and objects are imaged and recorded while a subject performs a manual task. Method. A video camera images the subject’s hand and objects to be manipulated in the SLO laser-beam raster, producing a video image of a subject’s hand, fingers, and objects on the subject’s retina while the objects are manipulated. A subject with bilateral central scotomas and an age-matched control subject with normal vision traced an ellipse with the index finger, tapped four disks in sequence, and carried out a pattern duplication task with pegs. Retinal positions of the fovea or preferred retinal locus (PRL), fingers, and objects were measured from digitized SLO images. Results. In all tasks, the fovea or PRL was directed to an object or position before the fingers arrived. This lead time was much greater for the scotoma subject than the control subject (∼1400 vs. ∼400 ms, respectively). The scotoma subject was much less accurate in placing the PRL and fingers on objects and required substantially more time for task completion than the control subject. Conclusions. The coordination of foveal fixation and finger placement found with the SLO method was similar to that found by others using eyetracking techniques with visually normal subjects. The presence of a central scotoma and use of a PRL caused marked deterioration in the quality of this coordination. Unlike eyetracking methods, the SLO technique does not require calibration because the positions of the fingers and objects are directly observable on the retina. This method could be useful in studying eye-hand coordination of individuals with scotomas that affect foveal vision.

A Veterans Administration medical center optometry residency program.

Abstract A form of postgraduate optometric education began in 1973 with the initiation of residency programs within two colleges of optometry. The availability of residency programs for optometrists, however, was essentially nonexistent until the Veterans Administration became actively involved. The first Veterans Administration Optometry Residency Program was established by the Kansas City Veterans Administration Medical Center and the Illinois College of Optometry. This paper briefly discusses the development and philosophy of this program and describes its clinical and academic content and future goals.

Visual–vestibular function in patients following an acoustic neuroma resection

Abstract Problem: Clinical evidence suggests a relationship between visual and vestibular function; however, little work has specifically targeted how visual deficits integrate with vestibular function to affect functional balance in postoperative acoustic neuroma patients. Methods: Visual, audiometric, and balance functions were tested in 24 participants (mean age, 46.17 ± 13.107) who were placed into 2 groups: 8 acoustic neuroma patients at least 6 months post a vestibulo-neurosection (PVN), and 16 age-matched controls (NN). Variables of interest included: near and far visual acuity (ACU) using standardized Snellen charts, pure tone averages at 1,000/2,000 Hz (AUD1000 and AUD2000), horizontal and vertical Vestibular Ocular Reflex (VOR) gain (Gain), phase (PHZ), and symmetry (SYM). In addition, functional balance was measured using the combined balance scores from the EquiTest™ Smart Balance Master protocol for Sensory Organization Test (SOT) and lateral bias of the center of pressure (X-bias). All tests were assessed specifically to each side tested (right vs left). Results: Nonparametric statistics using a Kruskal-Wallis H analysis revealed a significant difference in right and left visual acuity: right = 57.86 ± 13.309 vs 170.63 ± 55.985, P = 0.021; left = 72.50 ± 26.617 vs 201.25 ± 61.483; P = 0.050. In addition, there was a significant difference in horizontal VOR phase, 190.760 ± 2.2443 vs 198.225 ± 4.6931, P = 0.001. Balance scores also resulted in a significant difference, 79.27 ± 8.084 vs 66.13 ± 8.896, P = 0.002. All significance levels were tested using the Welch Robust Tests of Equality of Means at the 0.05 level. Conclusion: Results indicate that visual function was also significantly impaired in conjunction with deficits in balance and auditory function in the PVN group compared to the NN group. Significance: These results will aid in developing rehabilitation strategies for functional balance training for patients post an acoustic neuroma resection. Support: Supported in part by a grant from the School of Allied Health in the University of Kansas Medical Center.

Kansas City VAMC Optometry Residency Program: a survey of residents since 1975.

Background. The nation’s first one-year, Council on Optometric Education accredited hospital-based optometry residency program began at the Kansas City Veterans Affairs Medical Center in 1975. As part of the 25th anniversary review, past residents were surveyed to determine whether the residency had met their goals and influenced their postresidency activities. This is the first in-depth study of a single residency program. Methods. A 34-question survey was developed based on one previously used in a 1987 national study of Veterans Affairs residents. The survey was designed to provide data comparable to that found in other residency surveys. Results. Forty-eight of 50 former residents responded, and at least one survey was returned for every year from 1975 through 2000. One hundred percent of residents noted that the program met or exceeded expectations in patient diversity, workload, and level of responsibility. Additionally, almost 30% of residents currently or previously held Veterans Affairs staff positions, and they have collectively published 316 papers, 33 textbook chapters, and five textbooks. Conclusions. Judged by these responses, the Kansas City Veterans Affairs Medical Center Optometry Residency Program offers an exceptional clinical training program that surpasses resident expectations. Finally, former graduates of the program have made a significant contribution to patient care and to the optometric profession as demonstrated by their clinical, academic, and research accomplishments.