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Biomedical subjects

R L Lindstrom

Publications and source records attributed to R L Lindstrom.

At least 91 records · Page 5Linked to original sources
PubMed1988

The surgical management of overcorrection in myopic epikeratophakia.

Three patients underwent myopic epikeratophakia that resulted in overcorrection. The surgical management of these cases involved resuturing the myopic lenticule to flatten the peripheral curvature and reduce the amount of minus power. A reduction in the overcorrection was achieved in all cases.

Corneal Transplantation↗
PubMed1988

Paired arcuate keratotomy. A surgical approach to mixed and myopic astigmatism.

Twenty-five cadaver eyes were used to study the effect of paired arcuate keratotomy on corneal astigmatic changes. Paired arcuate incisions placed at optical zones of 5, 6, 7, 8, and 9 mm were progressively lengthened from 45 degrees to 60 degrees, 90 degrees, and, finally, 120 degrees. The corneal flattening in the meridian centered over the incisions and the corneal steepening 90 degrees away were quantified with each successive lengthening. Linear regression analysis showed a direct linear relationship of corneal astigmatic change (sum of corneal flattening and steepening, or delta K) to decreasing optical zone size as measured in millimeters and increasing incision length as measured in degrees. The delta K value ranged from 2.65 +/- 1.07 diopters to 22.05 +/- 3.55 D. The flattening/steepening coupling ratio mean was 1.47 +/- 0.41. Progressively longer paired arcuate incisions produced a predictable and titratable corneal flattening in the meridian centered over the incisions and a slightly smaller corneal steepening 90 degrees away, making the procedure ideal for mixed astigmatism.

Anthropometry↗
PubMed1988

Effect of a plano-convex posterior chamber lens on capsular opacification from Elschnig pearl formation.

Opacification of the posterior capsule occurs most commonly from Elschnig pearl migration or fibrosis. The physical contact of a posterior chamber lens, particularly one with a reverse optic, has been postulated to decrease the rate of capsular opacification by creating a barrier to Elschnig pearl migration. This randomized prospective clinical study comparing the 3M style 34S convex-plano optic and style 34R plano-convex (reverse) optic posterior chamber lens demonstrated a statistically significant reduction in capsular opacification by Elschnig pearls at one year in the reverse optic lenses (18.2% versus 7.6%, P = .03). No statistically significant difference in capsular fibrosis rates was noted (2.5% versus 4.5%, P = .48). The reverse optic implant also demonstrated greater iris to implant optic clearance.

Adult↗
PubMed1988

Four incision radial keratotomy.

Radial keratotomy is a constantly evolving procedure. This paper investigates the value of four incision radial keratotomy. The possible advantages of fewer incisions include increased corneal stability, lower risk of perforation, less potential of endothelial cell loss, decreased chance of overcorrection, and simplification of the procedure. We evaluated the results of four incision radial keratotomy in 55 eyes of 31 patients. Follow-up ranged from one to 18 months. Results in low myopia (-2.00 to -3.12 diopters) show 93% of the patients were 20/40 or better, 90% were within +/- 1 diopter of emmetropia, and no patients were overcorrected greater than 1 diopter. In moderate myopia (-3.25 to -4.37 diopters), 84% of the patients were 20/40 or better, 92% were within +/- 1 diopter of emmetropia, and no patients were overcorrected greater than 1 diopter. Regression analysis was performed and it was determined that the postoperative result was equal to .262 + [1.293 x preop spherical equivalent] - [1.166 x optical zone] + [0.56 x depth] + [.038 x age], R = .87.

Follow-Up Studies↗
PubMed1988

An experimental model for uveal touch syndrome.

Posterior chamber intraocular lenses (IOLs) were implanted in cat eyes after extracapsular cataract extraction or phacoemulsification. Various degrees of iris and IOL contact occurred. In 52% of the eyes in which contact was present, there was associated fibrovascular membrane formation, which was statistically significant when compared to eyes in which there was no iris-IOL contact. The eyes were examined histopathologically; proliferation of anterior cuboidal cells, as well as a fibrous response within the stroma, was noted in eyes with the most extensive contact. Human clinical correlates are discussed. This study demonstrates experimentally that the iris will not tolerate significant prolonged IOL contact.

Animals↗
PubMed1988

Surgical correction of postoperative astigmatism.

The photokeratoscope has increased the understanding of the aspheric nature of the cornea as well as a better understanding of normal corneal topography. This has significantly affected the development of newer and more predictable models of surgical astigmatic correction. Relaxing incisions effectively flatten the steeper meridian an equivalent amount as they steepen the flatter meridian. The net change in spherical equivalent is therefore negligible. Poor predictability is the major limitation of relaxing incisions. Wedge resection can correct large degrees of postkeratoplasty astigmatism. Resection of 0.10 mm of tissue results in approximately 2 diopters of astigmatic correction. Prolonged postoperative rehabilitation and induced irregular astigmatism are limitations of the procedure. Transverse incisions flatten the steeper meridian an equivalent amount as they steepen the flatter meridian. Semiradial incisions result in two times the amount of flattening in the meridian of the incision compared to the meridian 90 degrees away. Combination of transverse incisions with semiradial incisions describes the trapezoidal astigmatic keratotomy. This procedure may correct from 5.5 to 11.0 diopters depending upon the age of the patient. The use of the surgical keratometer is helpful in assessing a proper endpoint during surgical correction of astigmatism.

Adrenal Cortex Hormones↗
PubMed1988

Implantation of a posterior chamber lens without capsular support during penetrating keratoplasty or as a secondary lens implant.

We have devised a technique to fixate a posterior chamber lens in the ciliary sulcus when no posterior capsular support exists. Our short-term follow-up of 22 eyes with lenses thus fixated has shown these eyes to be quiet and to have good pupillary motility after at least 3 months. We believe this new technique is a significant advancement in corneal and anterior segment surgery.

Corneal Transplantation↗
PubMed1988

Visual loss following suture removal postkeratoplasty.

Suture removal following penetrating keratoplasty continues to plague surgeons as one of the most unpredictable aspects of this procedure. The patients presented here will detail three cases of endophthalmitis and one case of expulsive hemorrhage following suture removal. These events cannot be predicted. However, certain steps can be taken to minimize these potentially blinding complications. These steps include avoidance of through and through sutures, follow-up examination within 24 h of suture removal to look for signs of would leak, graft dehiscence or infection, use of appropriate antibiotics, elimination of dacryocystitis prior to keratoplasty, and particular vigilance in immunocompromised patients.

Adult↗
PubMed1988

Complications of Nadbath facial nerve block and a review of the literature.

In a retrospective study of complications resulting from the Nadbath facial nerve block, we identified three patients (0.25%) over a 2-year period. Complications included dysphonia, laryngospasm, unilateral vocal cord paralysis, and a sensation of the inability to breathe. As it exits the stylomastoid foramen, the facial nerve lies close to the vagus, glossopharyngeal, and accessory nerves. Particular care must be taken, therefore, when giving Nadbath blocks in very thin individuals. The use of hyaluronidase, which enhances effusion of the anesthetic agent, should probably be withheld.

Adult↗