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Biomedical subjects

A Jampolsky

Publications and source records attributed to A Jampolsky.

At least 19 recordsLinked to original sources
PubMed1991

Cortical recovery from effects of monocular deprivation caused by diffusion and occlusion.

Two forms of visual deficit were induced in 12 pairs of kittens (4-6 weeks of age) by monocular lid suture combined with either an opaque soft contact lens ('occlusion' amblyopia) or a clear lens ('diffusion' amblyopia) which had been kept behind the sutured eyelids for 5-9 weeks. The kittens were then reverse-sutured at the age of 9-15 weeks, and the previously open eye was occluded with an opaque lens for the next 5-7 weeks. We compared across the two groups the proportion of binocularly driven cells (group 2-6) and cells predominantly activated by stimulation of the initially deprived eye (groups 1-3). Both values were significantly higher in the 'occlusion' kitten, though the difference was small, compared to the 'diffusion' kitten. In addition, we measured visual acuity and peak contrast sensitivity for the two eyes in 4 of the 12 pairs, using the sweep VEP method applied under anesthesia and paralysis. The 'occlusion' kitten showed consistently better acuity and higher peak contrast sensitivity than the 'diffusion' kitten, when the initially deprived eye was tested. Taken together, the present results suggest that there is a difference in the depth of amblyopia caused by monocular 'occlusion' and monocular 'diffusion'. The cortical effects of the latter are more difficult to reverse than those of the former.

Amblyopia↗
PubMed1991

Length-tension recording system for strabismus surgery.

To meet the need for both scientific information and a clinical means for measurement of the mechanical parameters of the most difficult individual strabismus cases we present a technique for directly measuring and plotting the length-tension characteristics of the tissues supporting the eye. Semiconductor strain gauges mounted on the shanks of a custom machined eye forceps and an ultrasonic method of making continuous duction measurements of the eye have proved feasible. When the forceps are interfaced with a dedicated microcomputer, the system provides a permanent, quantitative, length-tension record displayed in real-time. The instrumented length-tension forceps system has provided a noninvasive means for quickly and simply assessing the mechanical underlying determinants of strabismus pathology in the office, the laboratory or in the operating room, and can aid in the planning and immediate intraoperative alteration of strabismus surgery. Under operator coordination, measurements can be made which precisely define the mechanical load which the eye muscles must move. The resulting objectively determined tissue stiffness asymmetries and muscle restrictions limiting ocular motion indicate the purely mechanical contributions to a patient's strabismus. Measurements of active force indicate the magnitudes and patterns of innervation over the entire range of gaze. By comparison of these active force and passive stiffness records, nerve signal imbalances may be quantitatively distinguished from mechanical imbalances in strabismus. It is the detailed interaction of these nonlinear muscle forces and mechanical elements which determines the position of each eye in strabismus and therefore the proper surgical treatment. A brief description of actual use and a few examples of clinical results are included from over 200 human records.

Calibration↗
PubMed1979

Lateral incomitancy in intermittent exotropia: cause and surgical therapy.

A hypothesis, previously proposed, of tight medial rectus muscles in conjunction with tight lateral rectus muscles associated with exodeviations as a cause of lateral incomitancy in intermittent exotropia is supported by clinical management. Three patients with these findings underwent bilateral medial rectus and lateral rectus recessions by means of the adjustable rectus recession technique. Primary position alignment was achieved, and rotations were balanced with the alleviation of the lateral incomitancy. The lateral rectus muscles were recessed an amount more than usual in order to compensate for the recession of the medial rectus muscles.

Adolescent↗
PubMed1979

An adjustable transposition procedure for abduction deficiences.

We used an adjustable transposition procedure in two cases of horizontal abduction deficiency (one of lateral rectus palsy and one of Duane syndrome with marked co-contraction). Primary position balanced alignment and maximum balanced rotations were obtained without inducing vertical deviation as the result of the transposition. The vertical force vectors were neutralized by the self-adjusting nature of the vertical rectus union. The procedure allowed for both intraoperative and postoperative adjustment of the result.

Child↗
PubMed1979

Current techniques of adjustable strabismus surgery.

Adjustable strabismus surgical procedures provide the opportunity to reposition a surgically altered muscle position, which is often necessary for nonaverage cases of strabismus correction. The usual surgical procedure is extended into the postoperative period (same hospitalization) so that the surgeon may satisfactorily monitor the total end result (by cover test and rotations) at the time of adjustment. Adjustable techniques should be considered whenever a desired goal is unlikely to be reached in one surgical session. Recent technical improvements allow satisfactory globe position control during the adjustment stage for ease of recession or resection adjustment. Globe stabilization is attained during surgery and the postoperative adjustment by means of a scleral loop handle, placed near the corneoscleral limbus. Millimeters of adjustment are easily estimated by means of a sliding suture knot technique.

Humans↗
PubMed1978

Intentional surgical overcorrection of acquired esotropia.

Fifty-eight patients with surgically treated acquired nonaccommodative esotropia were studied retrospectively, to ascertain what immediate surgical result gives the best chance for a postoperative bifoveal fusional result. Of the cases that were initially overcorrected (exodeviations), approximately two thirds were fusing six months or more after surgery. Of the cases that were initially aligned (orthophoric) or undercorrected (esodeviations), only one third were fusing after the same period. These results suggest that intentional surgical overcorrection of cases of acquired nonaccommodative esotropia that have a good fusional potential (ie, equal vision) does appear to be a desirable goal for the immediate postoperative period.

Adolescent↗
PubMed1978

The O'Connor cinch revisited.

The modified O'Connor cinch operation is a useful, but little used, adjustable resection operation. For increased understanding of its shortening and adjustment characteristics, a standard cinch was performed in animals and patients with strabismus. Animal studies showed that, as each strand of the cinch was removed, a small, relatively equal release of the cinch effect occurred. Measurement of the shortening obtained in patients with strabismus showed a consistent resection effect of about 4 mm. Review of 17 cases in which the cinch was used as part of the surgical treatment showed the technique to be adjustable by reducing the overcorrection in 6 cases. Ten to 20 prism dioptres of reduction in the deviation was obtained with adjustment of the cinch on the first postoperative day. All 17 cases had satisfactory adjustment. The largest residual deviation was 12 prism dioptres.

Adolescent↗
PubMed1977

A clinically useful eye movement recording system.

A simple, stable, and relatively calibration-free eye movement recording system for clinical application is described. This limbal sensing device makes use of a standard trial-lens clip that can be attached to the patient's spectacles, allowing easy and quick addition of lens or prism power. Horizontal eye movements or positions can be recorded with an accuracy of better than 1 degree over a 50-degree range; the linear range of the device is approximately 30 degrees.

California↗
PubMed1976

Mangement of infantile esotropia.

We evaluated the management of infantile esotropia-constant, alternating esotropia before 6 months of age-in 34 children. Planned one-state surgery for satisfactory mechanical alignment was highly predicatable (79 to 84%), and was obtained at any age. Stable bifoveal motor fusion was also obtained but was more frequent with alignment before 2 years of age. The use of postsurgical spectacle orthoptics (minus lenses or prisms, or both) increased the incidence of bifoveal fusion. Surgery alone resulted in bifoveal fusion in 6% of the cases, whereas an overall incidence of 33% bifoveal fusion resulted after the use of postsurgical spectacle orthoptics by some patients. Of those receiving postsurgical spectacle orthoptics, 53% obtained bifoveal fusion. This study demonstrated a correlation between the incidence of secondary A patterns (after surgery for V esotropia) and the amount of horizontal muscle surgery done in combination with bilateral inferior oblique muscle myectomies.

Age Factors↗
PubMed1975

Pseudoparalysis caused by anomalous insertion of superior rectus muscle.

Congential ectopia of the insertion of the superior rectus muscle to the superior border of the lateral rectus muscle was seen in a 4-year-old child. In all respects, this condition mimicked congenital superior rectus palsy. The resultant large hypotropla was completely corrected by repositioning the superior rectus to its normal anatomic position.

Child, Preschool↗
PubMed1975

Strabismus and pseudostrabismus with retrolental fibroplasia.

Three patients with temporal displacement of the macular secondary to retrolental fibroplasia had true strabismus in associations with amblyopia and pseudostrabismus related to a large, positive angle kappa. In one case, a headturn associated with the neutral point of nystagmus was also a presenting problem. Ocular deviation was measured by the light reflex test and the prism cover test, with particular attention paid to adequate cosmetic alignment. Large amounts of prism placed before the fixating eye resulted in loss of visual acuity, while eyes placed in a parallel position by surgical means may not appear to be straight. Thus, surgery can result in parallel ocular alignment while prismatic therapy may be required to center the pupillary light reflex and to provide satisfactory cosmetic appearance.

Accommodation, Ocular↗