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Biomedical subjects

M M Parks

Publications and source records attributed to M M Parks.

At least 55 records · Page 3Linked to original sources
PubMed1983

Denervation and extirpation of the inferior oblique. An improved weakening procedure for marked overaction.

Parks demonstrated that recession was more effective than myectomy at insertion or origin, or disinsertion for eliminating inferior oblique overaction. This study simultaneously compares an improved procedure, an extirpation of the inferior oblique that involves denervating it, to 14 mm recession in a prospective, consecutive series of 16 patients with symmetrical 4+ overaction of the inferior obliques; one technique (extirpation) performed on the right eye, and the other (14 mm recession) on the left. Mean duration of follow-up was 20.8 months (range 17 to 34 months). Extirpation resulted in 100% normal action, without residual overaction or underaction. Recession, however, resulted in 1+ to 3+ residual overaction in 12 cases (75%) and 4+ overaction requiring reoperation in two eyes (13%). It appears that extirpation of the inferior oblique is far superior to 14 mm recession for treatment of marked overaction of the inferior oblique.

Child↗
PubMed1983

Discriminant analysis of acquired esotropia surgery. Predictor variables for short- and long-term outcomes.

In a retrospective study, a computer-based stepwise discriminant analysis was used to create a biostatistical model of the results of surgery in acquired esotropia. One hundred seventy-two patients who had bilateral medial rectus muscle recession as an initial operative procedure with at least 6 months postoperative follow-up were studied. The outcome groups for the discriminant analysis were based on the ocular deviation 6 weeks after the first surgery and at the patient's last visit, or the presence or absence of stereopsis at the last visit. With respect to the two predominant ocular deviation groups (Esotropia or Success) 6 weeks after surgery, 11 independent variables were analyzed; those determined to be prognostic of the outcome grouping were refractive error of the left eye and preoperative deviation, in that order. With respect to ocular deviation at last visit, 146 patients were followed for over 2 years and were last examined when over 5 years of age; of the 12 independent variables analyzed, postoperative deviation at 6 weeks, refractive error of the right eye, and age of onset were predictive. With respect to stereopsis, 126 patients had similar follow-up; of the 11 independent variables analyzed, only postoperative deviation at 6 weeks was prognostic. The results indicate that in patients with acquired esotropia the postoperative deviation is the most important prognostic factor for both the maintenance of ocular alignment and the status of stereopsis; refractive error and the age of onset of the esotropia influence the ocular alignment at the last visit.

Age Factors↗
PubMed1983

Discriminant analysis of congenital esotropia surgery. Predictor variables for short- and long-term outcomes.

In a retrospective study, a computer-based stepwise discriminant analysis was used to create a biostatistical model of the results of surgery in congenital esotropia. One hundred fifty-seven patients who had bilateral medial rectus muscle recession as an initial operative procedure with at least 6 months postoperative follow-up were studied. The outcome groups for the discriminant analysis were based on the ocular deviation 6 weeks after the first surgery and at the patient's last visit, or the presence or absence of stereopsis at the last visit. With respect to the two predominant ocular deviation groups (Esotropia or Success) 6 weeks after surgery, 11 independent variables were analyzed; those determined to be prognostic of the outcome grouping were preoperative deviation, millimeters of medial rectus muscle recession, and interval between the onset of strabismus and surgery. With respect to ocular deviation at last visit, 105 patients were followed for over 2 years and were last examined when over 5 years of age; of the 12 independent variables analyzed, only postoperative deviation at 6 weeks was predictive. With respect to stereopsis, 94 patients had similar follow-up; of the 12 independent variables analyzed, preoperative deviation and age at surgery were prognostic. The results indicate that a smaller preoperative deviation and earlier surgical intervention increase the probability of achieving some degree of stereopsis in patients with congenital esotropia.

Age Factors↗
PubMed1983

Posterior lens capsulectomy during primary cataract surgery in children.

Concern continues about the best and safest method to surgically manage cataracts in children. Posterior capsulectomy and anterior vitrectomy with a vitreous suction cutter eliminates the need for secondary surgery. It is the best method to avoid development of amblyopia resulting from gradual posterior lens capsule opacification. However, cystoid macular edema is reported to occur more frequently with this approach as opposed to leaving the posterior lens capsule intact. Amblyopia, however, at this time may be a greater risk to final visual acuity than cystoid macular edema.

Age Factors↗
PubMed1983

Intermittent exotropia. Surgical results in different age groups.

The surgical results of 111 consecutive patients with intermittent exotropia treated via bilateral rectus muscle recession and having at least 2 years of follow-up are reviewed. These data are analyzed from a standpoint of three age groups at the time of surgery: younger than 3 years (41 patients), 3 years to younger than 6 years (42 patients), and 6 years to younger than 17 years (28 patients). The initial surgical results for all ages were as follows: 56% satisfactory, 38% undercorrected, and 6% overcorrected. After appropriate management (which was almost always surgical) in those patients initially either undercorrected or overcorrected, a satisfactory result was obtained in 95% of all patients comprising this series.

Adolescent↗
PubMed1982

Visual results in aphakic children.

Sixty-five patients less than 10 years of age had cataract surgery on 99 eyes. The visual prognosis depended on the cataract type and whether the treatment was undertaken during the critical period for development of the fixation reflex. All patients received the same surgical technique, aggressive optical correction, and occlusion therapy, if needed. Partial cataracts were the most frequent and the two largest groups were lamellar and axial. The visual outcome was excellent for the lamellar cataracts, whereas axial cataracts were the most amblyogenic. Obtaining a good visual result demanded an understanding of the complexities of amblyopia.

Amblyopia↗
PubMed1982

Surgery of bilateral superior oblique palsy.

Following head trauma, because the patient has no overt vertical or horizontal tropia to account for the complaint of diplopia, the symptoms are dismissed, when in fact cyclodiplopia resulting from the excyclotropic feature of bilateral superior oblique palsy is the cause. A prospective study of nine patients with bilateral superior oblique muscle palsy caused by head trauma and managed by an identical surgical regimen are presented. All patients had symptomatic cyclodiplopia that increased in downgaze. Cover testing performed in various gaze positions and in left and right head tilt positions plus the double Maddox rod tests confirmed the diagnosis. The four expected findings are left hypertropia (LHT) in right gaze and right hypertropia (RHT) in left gaze, RHT on right head tilt and LHT in left tilt, V pattern, and excyclodeviation. All patients received symmetrical bilateral superior oblique tendon surgery, using a modified technique originally described by Harada and Ito, which consisted of advancing the anterior tendon half along the equator of the globe toward the superior border of the lateral rectus muscle. Elimination of the cyclodiplopia symptom was achieved in all cases by reducing the quantity of excyclotropia.

Adult↗
PubMed1982

Dissociated vertical deviation: associated findings and results of surgical treatment.

The records of 80 consecutive patients with dissociated vertical deviation (DVD) were reviewed. The most frequent initial problem was esotropia, which was noted before 12 months of age in 67 patients. Latent nystagmus was present in 13 patients, and poor stereopsis was documented in 11 of the 29 patients tested. Resection of the inferior rectus muscle, the most frequent surgical procedure in this series, seldom resulted in total resolution of the DVD, but it often yielded cosmetic improvement.

Esotropia↗
PubMed1981

An analysis of treatment of congenital glaucoma by goniotomy.

We used goniotomy as the initial surgical procedure in 34 patients (50 eyes) with congenital glaucoma. An overall success rate of 88% was achieved with one or more goniotomies. The age at disease onset, level of intraocular pressure, and corneal diameter did not significantly influence the surgical outcome. The refractive error proved to be a valuable indicator of operative success or disease progression. A satisfactory visual outcome was associated with treatment by goniotomy.

Child, Preschool↗
PubMed1981

Clinical and computer-assisted analyses of preoperative and postoperative accommodative convergence and accommodation relationships.

A group of 329 patients who underwent bilateral medial rectus muscle recession for esodeviation were analyzed for factors most closely correlated with the outcome. The data evaluated included age of onset of strabismus, refractive error, year of surgery, age of surgery, sex, preoperative esodeviation, and clinical assessment of preoperative and postoperative heterophoria. Linear regression analysis was used to evaluate the relationships of these parameters. Computer-assisted logistic regression analyses and discriminant analyses were used to assess predictive variables for a postoperative increase or decrease in the accommodative convergence and accommodation (AC/A) relationship represented by the clinical assessment method.

Accommodation, Ocular↗
PubMed1980

Early-onset accommodative esotropia.

Twenty-one patients had esotropia diagnosed before age 12 months. In all of these patients esotropia was eliminated, at least initially, by antiaccommodative therapy consisting of either full hypermetropic spectacles or miotics, or both. Clinical findings evaluated in these patients were comparable to similar clinical factors studied in a larger series of patients with accommodative esotropia, most with onset after 12 months of age. In approximately 50% of these patients early-onset accommodative esotropia deteriorated to a nonaccommodative esotropia that required surgery despite aggressive antiaccommodative therapy. All but one of the surgically treated patients continued to need hypermetropia spectacles postoperatively to maintain alignment.

Accommodation, Ocular↗
PubMed1979

Filtering surgery in children: barriers to success.

The use of trabeculectomy in advanced pediatric glaucoma is reviewed. Intraocular pressure was controlled in only 50% of the patients, and the best visual results was 20/200. Complications of vitreous loss, scleral collapse, ectasia, retinal detachment, and endophthalmitis were encountered. No evidence was found to support the claim that in the seriously compromised buphthalmic eyes, trabeculectomy is safer than other filtering operations since it filters under a scleral flap.

Adolescent↗
PubMed1978

Management of posterior lenticonus complicated by unilateral cataract.

We studied 21 patients with 23 eyes with posterior lenticonus. Twenty-one of the eyes developed progressive cataractous changes that required lens aspiration in 19 eyes when vision reduction was 6/30 (20/100) or less. The inherent weakness of the diaphanous portion of the posterior lens capsule contributed to disruption of the normal lamellar arrangement of the lens fibers resulting in cataractous changes. Amblyopia was the most significant visual problem associated with posterior lenticonus. Fifteen of the 19 operated eyes in this study were amblyopic and nine of the 15 were improved to 6/15 (20/50) or better vision with occlusion therapy, after surgical aspiration of the cataractous lens and contact lens therapy.

Adolescent↗
PubMed1977

Doyne Memorial Lecture, 1977. The superior oblique tendon.

New concepts concerning the anatomy of the tissues surrounding the superior oblique tendon are presented. A safe visual approach to the tendon after its penetration through Tenon's capsule is described. The various surgical procedures and techniques developed to weaken the overacting superior oblique muscles associated with A pattern and the taut superior oblique muscle found in Brown's syndrome are reviewed.

Adolescent↗