Arkady Selenow

Reduction of asthenopia in patients with convergence insufficiency after fusional vergence training

ABSTRACT Seven patients with convergence insufficiency and related asthenopia underwent automated fusional convergence training. A matchedsubjects control group crossover design was used to reduce placebo effects. All patients showed significant increases in vergence ranges with concurrent marked reduction of symptoms after training. All patients showed a flattening of and an increase in the base‐out portion of their fixation disparity curve. Our results demonstrated the effectiveness of fusional vergence training in reducing asthenopia in these patients. Subsequent accommodation and vergence training using traditional orthoptic procedures yielded further reduction of asthenopia, as well as an increase in the base‐out fusional range.

Reduction of asthenopia after accommodative facility training.

ABSTRACT Five patients reporting asthenopia secondary to accommodative deficiencies underwent automated accommodative facility training. A matched‐subjects, crossover design was used to control for placebo effects. All patients receiving automated accommodative training showed a marked increase in accommodative amplitude along with a concurrent reduction of asthenopia. Decreases of blur and increases of reading time were the most frequently reported changes by patients. This experiment shows the effectiveness of automated accommodative training in reducing asthenopia and improving accommodative facility.

Assessing visual performance with progressive addition lenses.

Purpose. As a result of lens design limitations, progressive addition lenses (PAL’s) present a limited field of view for tasks at intermediate distances, such as with computers. To assess whether this limitation results in diminished visual performance, PAL’s were compared with single-vision lenses in four different types of reading tasks in a computer workplace environment. Methods. Adult subjects performed four computer-based reading tasks using both single-vision lenses and PAL’s at an intermediate distance of 64 cm. Results. Single-vision lenses performed significantly better than PAL’s in one task, with a trend for better performance in another task. There was no difference in performance for the remaining two tasks. Conclusions. Visual performance tests that involved stimuli subtending the widest visual angles and demanded more fixational shifts were more sensitive in discerning performance differences between the lens designs. In general, PAL’s showed marginally diminished performance compared with single-vision lenses, presumably due to their restricted intermediate channel.

Static aspects of accommodation in human amblyopia.

Static aspects of accommodation in human amblyopia were investigated. Abnormalities uncovered included decrease in accommodative controller gain, decrease in slope of the accommodative stimulus/response curve, decrease in accommodative amplitude, and increase in depth of focus. Orthoptic therapy improved accommodative function in the amblyopic eye. Similar defects, but of lesser magnitude, were frequently found in the nondominant eyes of subjects in related test groups. This included former amblyopes who had received successful orthoptic therapy in their youth, which suggested lack of complete and/or maintained recovery of accommodative function, and strabismics without amblyopia, which suggested that the effects of strabismic suppression contributed to the accommodative deficits found in some strabismic amblyopes. The accommodative abnormalities found in our amblyopes were attributed to the effects of early, prolonged, abnormal visual experience on the sensory visual system.

Rotational stability of toric soft contact lenses during natural viewing conditions.

Purpose. To compare objectively the rotational stability of two differently designed toric soft contact lenses over a range of natural viewing conditions using a novel infrared, video-based technique. Methods. Two contact lenses using different methods of stabilization were assessed: Accelerated Stabilization Design (ACUVUE ADVANCE for ASTIGMATISM) and Lo-Torque Design (B&L SofLens Toric). Four tasks involving saccades were performed: settling time with free viewing, reading, visual search, and execution of large versional tasks. Lens position (degrees of rotation) was continuously recorded with a head mounted, infrared, video-based system and a digital photo slit-lamp in 20 adult subjects. All measurements were obtained from the left eye under binocular viewing conditions with contact lenses on both eyes. Results. The ACUVUE lens was significantly more stable during the settling time and large saccadic versional tasks than the SofLens. For the two other tasks (reading, visual search), performance was similar. Conclusion. The ACUVUE design was superior in stability for two of the four conditions tested. This resulted in a more stable lens immediately after insertion as well as during some visual tasks involving either naturally occurring or programmed large versional eye movements. Both lens designs provided acceptable performance in terms of induced astigmatism produced by off-axis rotation.

Vision Function Recovery During Orthoptic Therapy in an Exotropic Amblyope with High Unilateral Myopia

ABSTRACT Orthoptic therapy was instituted in a 61/2‐yearold patient having deep amblyopia, constant exotropia, and high unilateral myopia. The combination of these factors pointed toward a poor prognosis for attainment of normal monocular and binocular vision function. Rates of recovery of several vision functions were monitored during orthoptic therapy. Results showed marked improvement in most areas, thus providing evidence of neural plasticity at multiple sites in the visual pathways.

Results of surgical treatment of intermittent divergent strabismus.

ABSTRACT Inasmuch as surgery is often suggested as the primary treatment for intermittent exotropia, we undertook an extensive literature search to ascertain the outcome of this treatment. Surprisingly, only 22 papers were located which gave presurgical and postsurgical results for intermittent exotropia using reasonably clear success criteria. Many other papers were located but were excluded because they either failed to state the criteria used, lumped exotropia and esotropia together in their reported successes, or used orthoptics along with surgery. The total number of cases reported in the 22 acceptable papers was analyzed in terms of four levels of success to permit comparison across studies. These four levels were: functional success, motor alignment, cosmetically acceptable, and unsuccessful (no change or worse). The data are tabulated and summarized.

Use of forced preferential looking for measurement of visual acuity in a population of neurologically impaired children.

ABSTRACT The forced preferential looking (FPL) technique has been used clinically, to assess visual acuity in infants for the past decade. It is generally accepted that the effectiveness of the procedure extends to the upper limit of 10 months of age. The authors discuss clinical observations on the viability of FPL as an effective technique in the measurement of visual acuity in an older population of neurologically impaired children.