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Biomedical subjects

M M Parks

Publications and source records attributed to M M Parks.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Long-term results of bifocal therapy for accommodative esotropia.

We studied the long-term course of 65 accommodative esotropes who required bifocals to maintain alignment at near. Average follow-up was 10.5 years. Forty patients (61.5%, group DC [bifocals discontinued]) were able to discontinue bifocal use after an average of 5.5 years wear. Twenty-five (38.5%) continued to wear bifocals (or a suitable alternative such as reading glasses), after an average 9.7 years of follow-up. Surgical correction of deteriorated accommodative esotropia was performed for 20 patients (50%) in group DC, and nine (36%) of those in group C[bifocals continued]. Surgery produced an average reduction in the accommodative convergence relationship (near esodeviation in prism diopters [pd] minus corrected distance measurement, AC/A) of approximately 10 pd in both groups. Surgical patients unable to discontinue bifocal wear began with a clinically higher AC/A than those in group DC. Non-surgical patients in group DC experienced spontaneous improvement of the AC/A over time (average, 6.2 pd). On average, this did not occur in those of group C. Average age of bifocal discontinuation was 9.7 years in surgical patients and 9.3 years in the non-surgical. Surgical patients had significantly lower hyperopia (+2.4 diopters [D]), than non-surgical (+3.5 D), and an earlier age of onset of bifocal wear (3.29 versus 4.64 years). Although bifocals may be successfully discontinued in a majority of patients at an average age of 9.5 years, a significant percentage require long-term wear, some, despite surgery. The only factor that predicted long-term bifocal wear was a relatively high AC/A.

Accommodation, Ocular↗
PubMedDate not supplied

Response of coexisting underacting superior oblique and overacting inferior oblique muscles to inferior oblique weakening.

One hundred twenty-six eyes with inferior oblique overaction and coexisting superior oblique underaction were retrospectively studied pre- and postoperatively. The data show that weakening the inferior oblique corrected the underaction of the superior oblique, and that overcorrection of the underacting superior oblique was unusual. Eyes were selected for study if superior oblique underaction coexisted with inferior oblique overaction preoperatively. The operation chosen for the inferior oblique in every case was determined by the quantity of inferior oblique overaction and whether prior surgery on the inferior oblique had been performed. A denervation and extirpation was the final inferior oblique weakening procedure in all except three of these eyes. Congenital or acquired superior oblique palsy cases were not included in this study. To eliminate eyes with superior oblique palsy, we excluded any patient with a history of serious head trauma; a vertical deviation in the primary position greater than 5 prism diopters except if caused by dissociated vertical deviation; the complaint of torsional diplopia controlled by an anomalous head posture; or a positive Bielschowsky head tilt test. The mean preoperative superior oblique action was -2.4 on a scale of 0 to 4, and this corrected to a mean postoperative action of -0.2, (P less than .001). This was accompanied by a change in the mean inferior oblique action of +3.8 to -0.2, (P less than .001). These same results were found regardless of the preoperative action of either the inferior or superior oblique. With regard to the postoperative superior oblique action, 22 cases were undercorrected, 2 were overcorrected, and 102 were normal.

Adolescent↗
PubMedDate not supplied

Results of combined surgery on the superior oblique and horizontal rectus muscles for A-pattern horizontal strabismus.

Results obtained in 32 patients with A-pattern horizontal strabismus and overacting superior oblique muscles treated with combined bilateral superior oblique tenotomies and bilateral symmetric surgery on the horizontal rectus muscles were analyzed retrospectively. The magnitude of reduction of the A-pattern correlated positively (r = 0.69) with the size of the preoperative A-pattern. Overall, 27 of the 32 patients (84%) had a satisfactory reduction in their A-pattern. Esodeviated patients received less correction in the primary position than exodeviated patients. Postoperative complications were minimal if the superior oblique tendon was hooked under direct visualization, and minimal dissection was performed on the surrounding tissue prior to transecting it near the nasal side of the superior rectus muscle.

Child↗
PubMedDate not supplied

Binocularity in accommodative esotropia.

One hundred twenty-seven medical records of patients with accommodative esotropia met our inclusion criteria and were analyzed. All included patients were within 10 prism diopters of orthophoria and had stereopsis and other binocular sensory test results recorded at their latest visit. Bifixation, defined as stereopsis of 50 arc seconds or better, was present in 31 patients (24%) with an average follow up of 89 months. Monofixation (peripheral fusion) was present in the remaining 96 patients (76%) with an average follow up of 84 months. Patients with bifixation were less likely to have presented with constant esotropia (19% vs 39% [P = .04]) and were more likely to be aligned within 8 delta of orthophoria in their first glasses (84% vs 21% [P < .0001]). No patient with bifixation had constant esotropia longer than 4 months. In addition, patients with bifixation were less likely to have worn bifocals (39% vs 59% [P = .09]), or undergone esotropia surgery (23% vs 62% [P < .0001]). These data suggest that maintenance of bifixation is possible in accommodative esotropia if the eyes are straightened before or shortly after the esodeviation becomes constant. With this early therapy, amblyopia and deterioration of ocular alignment are also less likely.

Accommodation, Ocular↗
PubMedDate not supplied

Prevalence of primary monofixation syndrome in parents of children with congenital esotropia.

The prevalence of primary monofixation syndrome (MFS) in the general population is approximately 1%. This study was performed to determine the prevalence of primary monofixation in biological parents of children with congenital esotropia. Ninety children with congenital esotropia were seen between November 1991 and June 1992 by one ophthalmologist (M.M.P.). One hundred and twenty-nine biological parents of these children were screened for sensorimotor abnormalities. Twelve parents were found to have secondary MFS and were removed from the analysis. This left 78 apparently non-strabismic families consisting of a total of 117 parents. Seven parents were identified as having primary MFS. The prevalence of primary MFS in this population is 9% of families and 6% of parents. Congenital esotropia is believed to be inherited in a multifactorial fashion. We believe that this increase in the prevalence of primary MFS compared to the general population lends support to the hypothesis that primary MFS may be a mild (subthreshold) effect of the "gene(s)" that cause congenital esotropia.

Adult↗
PubMedDate not supplied

Myopic shift after cataract removal in childhood.

BACKGROUND: Children who have had cataract removal tend to have decreasing hyperopia (myopic shift) as they grow older. We wondered if the rate of myopic shift could be determined by age at surgery, cataract type, glaucoma, or other factors. METHODS: We studied 156 aphakic eyes of children who had cataract surgery before age 10 and documented refractions for more than 3 years. Refraction was corrected with contact lenses and spectacles; glaucoma was managed with medicine and surgery. Stepwise multiple regression was used to analyze differences in the rate of myopic shift between subgroups. RESULTS: The average refraction tended to follow a logarithmic decline with age (P < 0.01, R2 = 0.97). The average rate of myopic shift (the slope of spectacle plane refraction vs log of age, where age is in years and log is base 10) was -5.5, with a standard deviation of 3.8. Age at surgery had a small but statistically significant effect on the rate (P < 0.01, R2 = 0.04). No other studied factor reached statistical significance. However, among the 86 eyes with cataract removal after age 6 months, age at surgery was not as significant (P = 0.21), and unilateral cataract eyes tended to have a greater rate than bilateral cataract eyes (-7.7 vs -5.7; P = 0.05, R2 = 0.05). CONCLUSIONS: Aphakic refraction tends to follow a logarithmic decline with age. The rate of myopic shift is determined partly by age at surgery and whether the cataract was unilateral or bilateral, although the effects are small. A wide variation in the rate of myopic shift exists. The following factors made little difference in the rate: cataract type, glaucoma, sex, side, and best corrected visual acuity.

Aging↗
PubMedDate not supplied

Transection of the superior rectus muscle during intended superior oblique tenotomy: a report of three cases.

Reported complications of superior oblique surgery include postoperative vertical or torsional deviation, Brown's syndrome, head tilt, blepharoptosis, and conversion of an A-pattern to a V-pattern. McNeer reported three cases of postoperative vertical deviation, one of which was attributed to severing of the superior rectus tendon. We report three additional cases of inadvertent unrecognized transection of the superior rectus during intended superior oblique tenotomy to emphasize the importance of direct visualization of these tendons during surgery.

Adult↗