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Biomedical subjects

M M Parks

Publications and source records attributed to M M Parks.

At least 19 recordsLinked to original sources
PubMed1997

Theoretic refractive changes after lens implantation in childhood.

OBJECTIVE: Children with aphakia tend to have decreasing hyperopia as they grow older. No large study of the long-term refractive changes in children with pseudophakia has been published, although myopic shifts of greater than 10 diopters (D) have been reported. The authors used the refractions of children with aphakia and long follow-up to calculate the theoretic long-term refractive effects of pseudophakia. DESIGN: The study design was a chart review of eyes that underwent cataract surgery before age 10 with documented refractions for more than 7 years. PARTICIPANTS: Ninety-three eyes were studied. INTERVENTION: The initial aphakic refractions of the study eyes were used to calculate the intraocular lens (IOL) powers that would have been required to give emmetropia at cataract removal. The aphakic refractions at last follow-up were used to calculate the final pseudophakic refractions, and these were compared with the predictions of a logarithmic model of myopic shift. RESULTS: The mean follow-up time was 11 years. The median calculated pseudophakic refraction at last follow-up was -6.6 D with a range of -36.3 to +2.9 D. Children who underwent surgery in the first 2 years of life had a substantially greater myopic shift than older children (P < 0.001) and a larger variance in this myopic shift (P < 0.001). The logarithmic model accurately predicted the final refraction within 3 D in 24% of eyes undergoing surgery before 2 years of age and in 77% of eyes undergoing surgery after this age. CONCLUSIONS: Pseudophakia in children is predicted to result in a large quantity of myopic shift, particularly in very young children. An IOL power chosen to leave a child initially hyperopic should lessen both the quantity of myopic shift and the extreme myopia that can result with growth. The surgeon who implants IOLs in young children must be prepared for a wide variation in long-term myopic shift.

Cataract Extraction↗
PubMed1995

Acquired posterior lentiglobus.

PURPOSE/METHODS: An infant examined by three ophthalmologists was found to have unilateral posterior lentiglobus, which subsequently developed bilaterally by 15 weeks of age. RESULTS/CONCLUSIONS: The onset of posterior lentiglobus may be congenital or acquired. Infants with unilateral cataracts whose family history indicates early-onset lens opacities require careful and frequent examinations of the fellow eye.

Cataract↗
PubMed1994

Autosomal dominant congenital cataract. Interocular phenotypic variability.

PURPOSE: While intrafamilial morphologic heterogeneity of autosomal dominant congenital cataracts has been well established, interocular variation in individual patients of described pedigrees is small. The authors describe a seven-generation family with 48 of 138 individuals known to be affected with autosomal dominant congenital cataracts of the pulverulent type. Affected patients exhibit a seemingly random expression of either unilateral or bilateral lens opacities. METHODS: Ophthalmic and medical histories were obtained, complete ophthalmologic examinations were performed, blood samples were drawn, and transformed lymphoblastoid lines were established on 53 patients. Eighty-five members of the family were unable to be examined. RESULTS: Twenty-eight of the 53 individuals examined had congenital cataracts. Of these patients, 19 eyes (8 right eyes and 11 left eyes) were unilateral and 9 were bilateral. The clinically unaffected eye in patients with unilateral cataracts showed no evidence of lenticular opacity under detailed slit-lamp examination. Severity of the cataracts included a subtle unilateral zonular cataract with 20/20 visual acuity, bilateral inner fetal nuclear pulverulent opacities with 20/16 visual acuity in both eyes, and dense unilateral and bilateral nuclear cataracts requiring early surgical removal. Incorporating the historic data on patients who were not examined, we found 48 affected members (28 unilateral, 17 bilateral, 3 obligate carriers who were not examined). CONCLUSIONS: Hereditary cataracts typically are symmetric in affected individuals. The authors describe a large pedigree with the apparently random expression of an autosomal dominant gene as either unilateral or bilateral cataract. To their knowledge, this is the first such family described in the literature. Currently, work is under way to determine if the causative gene is linked to previously defined cataract loci on chromosomes 1, 2, or 16.

Cataract↗
PubMed1993

Long-term visual results and complications in children with aphakia. A function of cataract type.

PURPOSE: Previous studies of outcome in children with aphakia have approached the data by grouping patients according to features such as age at surgery, type of procedure, or some other common attribute. The purpose of this study is to identify factors predictive for visual outcome and complications in pediatric patients with cataracts. METHOD: One hundred seventy-four eyes in 118 patients underwent lensectomy and anterior vitrectomy for congenital or juvenile cataracts. All received early optical correction, occlusion therapy when necessary, and follow-up for at least 6 months. Visual outcome and complications were analyzed statistically to determine predictive factors. Features analyzed included cataract type, laterality, age at onset, follow-up, and corneal size. RESULTS: Statistical analysis showed that the most important predictor of long-term visual outcome and complications is cataract type. Visual outcome differed significantly by cataract type, with best results in the lamellar and posterior lentiglobus groups. Unilateral cases had a mean acuity lower than bilateral cases. Other factors, such as age at surgery and corneal size, were less predictive but closely linked to cataract type. Complications, such as aphakic glaucoma, also were more closely linked to the type of cataract than to other variables. CONCLUSION: The results indicate that an important determinant of long-term outcome and complications in aphakic children is cataract type. Other features were found to be closely correlated to cataract type and were not independently significant.

Age Factors↗
PubMed1992

Stereopsis after congenital monocular cataract extraction.

Congenital monocular cataract extraction was performed on a 1-day-old baby girl and a hydrophilic contact lens was fitted. A progressive regimen of part-time occlusive therapy was then instituted. Eight years later, the girl has a visual acuity of 20/25 in the operated-on eye and 50 seconds of arc of stereoacuity that has been confirmed by an independent pediatric ophthalmologist. This patient demonstrates the potential for high-grade stereopsis in congenital monocular aphakia.

Cataract↗
PubMed1992

Surgical treatment of subluxated lenses in children.

BACKGROUND: Surgical removal of subluxated lenses had traditionally been discouraged because of concerns about poor surgical results and unacceptably high complication rates. METHODS: The authors reviewed the surgical results of 29 eyes in 15 consecutive patients who were operated on for subluxated lenses. RESULTS: Best-corrected visual acuity improved in all 29 eyes and was limited only by amblyopia. There were no significant complications in follow-up ranging from 5 months to 12 years. CONCLUSION: Modern surgical techniques using vitrectomy instruments allow the vitreous to be handled more effectively and have led to improved results and lower complication rates. Surgery for subluxated lenses can be done effectively and safely when indicated.

Child↗
PubMed1990

Glaucoma in oculo-dento-osseous dysplasia.

Two patients with oculo-dento-osseous dysplasia developed glaucoma in infancy or early childhood. Aggressive surgical management resulted in the preservation of vision in both patients in at least one eye. A review of published reports disclosed that glaucoma in oculo-dento-osseous dysplasia develops at different ages and is possibly secondary to a variety of mechanisms. Glaucoma is the main cause of visual loss in this syndrome, for which patients otherwise have a good prognosis for life and intellect. Early screening for glaucoma in oculo-dento-osseous dysplasia is mandatory, especially when there are symptoms that suggest high intraocular pressure.

Abnormalities, Multiple↗
PubMed1990

Recognition and repair of the "lost" rectus muscle. A report of 25 cases.

Twenty-five consecutive cases of lost muscle over a 10-year period are presented with regard to etiology, clinical presentation, operative findings, and treatment results. All patients showed a large-angle strabismus and all muscles had marked limitation of excursion in its field of action. This complication of ocular surgery or trauma, unlike the slipped muscle which has its empty capsule attached to the sclera, is characterized by the absence of any attachment of the muscle or its capsule to the sclera. Eleven of the 25 muscles were retrievable largely because of attachments through intermuscular septum to adjacent oblique muscles. The remaining 14 muscles were considered irretrievable, and these patients underwent a muscle transposition procedure. The clinical features and surgical repair of the lost muscle are described and compared with those of the slipped muscle.

Humans↗
PubMed1990

Results from 7-mm bilateral recessions of the medial rectus muscles for congenital esotropia.

We reviewed the surgical records of 77 patients who had undergone 7-mm bilateral medial rectus recessions for large-angle congenital esotropia. The mean age of onset of esotropia in these patients was 3.5 months, and the mean age at the time of surgery was 12.9 months. The mean preoperative deviation was 69 delta of esotropia. This procedure resulted in satisfactory horizontal alignment in 47 patients (61%) at their latest follow-up examination (mean, 27 months; range, 6 months to 6 years). The esotropia was undercorrected in 21 patients (27%) and overcorrected in nine (12%). Amblyopia was noted in 30%, oblique muscle dysfunction in 44%, and dissociated vertical deviation in 36% of the patients. Regression analysis of multiple variables showed alignment at 6 weeks to be the only predictor of the final outcome (R = .83). Extramacular fusion was achieved in 10 of 11 patients for whom reliable sensory data were available. The mean age at surgery of these patients was 9.7 months. Seven-millimeter bilateral medial rectus recessions are an effective alternative to three- and four-muscle procedures in the initial treatment of large-angle congenital esotropia during infancy.

Amblyopia↗
PubMed1989

Primary inferior oblique overaction in congenital esotropia, accommodative esotropia, and intermittent exotropia.

A statistical analysis of the onset and natural history of primary inferior oblique eye muscle overaction (IOOA) was conducted using the records of 456 strabismus patients. With 5 years or more of follow-up, IOOA developed in 72% of congenital esotropes (CETs), 34% of accommodative esotropes (AETs), and 32% of intermittent exotropes (X[T]s) at an average age of 3.6, 5.2, and 5.2 years, respectively. Incidence of IOOA was positively related to the number of horizontal surgeries in CETs but not in AETs or X(T)s. Incidence was not related to age of onset of strabismus, time from onset of strabismus to surgery, age at first surgery, or decompensation of ocular alignment. Mild IOOA did revert to normal in 12 patients after only horizontal surgery. The association of IOOA with dissociated vertical deviation, as well as symmetry, range of age of detection, and recurrence after surgery are also explored.

Accommodation, Ocular↗
PubMed1988

Congenital esotropia vs infantile esotropia.

The term congenital esotropia has been challenged for many years. The basis of this challenge is that the deviation is not confirmed connatally. However, the term congenital esotropia is valid based on clinical observations and is easily separated from other forms of acquired esotropia.

Age Factors↗
PubMed1987

Simultaneous superior oblique tenotomy and inferior oblique recession in Brown's syndrome.

The technique and results of simultaneous superior oblique tenotomy and 14-mm inferior oblique recession for true Brown's syndrome are presented for 16 eyes of 13 patients. A good or excellent result was achieved in 15 of 16 eyes (94%). Reoperation for overcorrection was not necessary; however, repeat tenotomy was required in two cases. Inferior oblique underaction was present in 12 of 16 eyes (75%) in the early postoperative period; however, elevation in adduction improved over time. At most recent examination, 92% of eyes demonstrated greater than 25 degrees elevation in adduction. Underaction of the superior oblique occurred in 3 of 16 eyes (19%). A simultaneous superior oblique tenotomy and inferior oblique recession is recommended in all patients selected to undergo surgery for true Brown's syndrome to prevent reoperation for iatrogenic superior oblique palsy.

Adolescent↗
PubMed1986

After the eyes are straightened what is the ophthalmologist's responsibility?

Occlusion, glasses, prism therapy, miotics, fusional vergence stimulation, plus more surgery are required frequently in various combinations for a high percentage of patients whose strabismic eyes are straightened by surgery. Amblyopia is a serious sequelae befalling children who are dismissed following satisfactory surgery. Their best possible postoperative status is monofixation (absence of bifixation), despite having straight eyes. Unless they alternate fixation, amblyopia is prone to either occur or recur. Also, either a gradual change in motor innervation to the extraocular muscles or a cicatricial scarring process may subtly cause subsequent strabismus. Hence, despite straight eyes postoperatively the surgeon's responsibility continues.

Amblyopia↗
PubMed1986

Familial congenital superior oblique palsy.

Four pedigrees, each with two or more cases of congenital superior oblique palsy among immediate family members, are presented. Except for a single case report in 1926, this disorder has not been known to occur in a hereditary manner. Theories of pathogenesis of congenital fourth cranial nerve palsy are discussed, with special reference to the hereditary occurrence of this disorder. Analogy is drawn between the familial forms of congenital superior oblique palsy and Duane's syndrome.

Adolescent↗