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Biomedical subjects

K S Morgan

Publications and source records attributed to K S Morgan.

48 records · Page 3Linked to original sources

The use of epikeratophakia grafts in pediatric monocular aphakia.

Epikeratophakia is a form of refractive surgery in which the recipient's epithelium is removed and a pre-shaped donor lenticule is sutured to the patient's cornea. Seventeen patients ranging in age from two months to 6.6 years received 19 epikeratophakia grafts for the correction of aphakic vision. The correction provided by the graft in combination with vigorous amblyopia therapy has yielded some improvement in vision in the 12 patients with successful grafts. This procedure may be particularly suitable for pediatric aphakic patients because it is extraocular and reversible and may be employed as a secondary procedure or in conjunction with cataract extraction. Only with longer follow-up of these and additional patients can these preliminary results be validated and the risk/benefit ratio of this procedure be assessed.

Aphakia, Postcataract↗

Oral fluorescein angioscopy in aphakic children.

Seven children who had undergone removal of congenital cataracts were evaluated postoperatively for cystoid macular edema during outpatient visits. Fluorescein was administered orally in a fruit juice cocktail, and the eyes examined by angioscopy 10-20 minutes and 45-60 minutes after dye ingestion. No evidence of macular leakage was observed in any of the 11 eyes examined. It appears that this diagnostic procedure is feasible in young patients, and that the incidence of cystoid macular edema after congenital cataract extraction may be less than has been previously reported.

Aphakia, Postcataract↗

Epikeratophakia in children with corneal lacerations.

Epikeratophakia grafts were used to optically correct aphakia in six children who suffered traumatic cataracts and corneal lacerations which were greater than 3 mm in length. The ages of the patients at the time of corneal laceration ranged from nine months to 3 3/12 years. Five of the six grafts were successful. The average increase in corneal curvature was 16.11 diopters with an average over-refraction of -0.73 diopters. The deprivation interval in the five children with successful grafts ranged from two months to two years, and the average visual acuity for the four verbal patients with successful grafts was 20/60. This series demonstrates that epikeratophakia grafts can be successfully applied to scarred and irregular corneas and may be superior to penetrating keratoplasty in some cases, because epikeratophakia allows for a prompt restoration of visual function.

Astigmatism↗

Epikeratophakia in children with traumatic cataracts.

Epikeratophakia provides a permanent optical correction for aphakia in children with congenital or traumatic cataracts; suturing the epikeratophakia graft onto the cornea eliminates the problems of contact lens or spectacle non-compliance in these young and generally uncooperative patients and provides tectonic support to scarred and irregular corneas. Eighteen children under the age of six years underwent epikeratophakia for the correction of aphakia after the removal of trauma-induced cataracts. Graft success rate was 88%; the average change in keratometry in the patients with successful grafts was 14.82 +/- 2.0 diopters. In the 13 patients eligible for visual acuity tabulation, preoperative acuities ranged from light perception to 20/200, and postoperative acuities ranged from hand motions to 20/30. Ten (77%) had acuities of 20/80 or better. Poor results in three patients with less than 20/200 acuities were likely the results of non-compliance with amblyopia therapy. Present work indicates that in cases of traumatic cataract, the epikeratophakia procedure facilitates amblyopia therapy and decreases the astigmatism in scarred and irregular corneas.

Cataract↗

Secondary cataracts in infants after lensectomies.

Three infants, one who was two weeks old, and two who were two months old, underwent lensectomy and vitrectomy in a total of four eyes for congenital cataracts by means of an automated suction cutter. Two patients with unilateral opacities underwent combined cataract extraction and epikeratophakia, and one with bilateral congenital cataracts underwent cataract extractions and was fit with extended wear contact lenses. In all cases, the surgery involved at least a 5-mm posterior capsulotomy with a shallow anterior vitrectomy, and was uneventful. Three of the four eyes developed new opacities that required surgical removal three to five months after the original surgery. Cytological evaluation of the specimen obtained from one patient showed this material to be lens epithelium. In all three cases, the material grew without the support of the posterior capsule; in one patient the material appeared to have seeded onto the iris. This previously unreported complication in infants with congenital cataracts who have undergone posterior capsulotomy and anterior vitrectomy emphasizes the need for frequent retinoscopies on such patients. The absence of the posterior capsule does not guarantee that these children will not develop secondary growth of lens epithelium which may obstruct the visual axis.

Cataract↗

Lensectomy in an infant with cri du chat syndrome and cataracts.

We report an 11-month-old infant with cri du chat syndrome and cataracts. The chromosomal abnormality was transmitted via a balanced 5/11 translocation from a phenotypically normal mother. The child underwent bilateral cataract extraction and was fitted with extended wear contact lenses. Congenital cataracts may be associated with cri du chat syndrome.

Cataract↗

Combined cataract extraction and epikeratophakia in children.

Nineteen children between the ages of 2 1/2 and 6 1/2 years who had cataracts not associated with trauma and who were judged to be poor candidates for contact lens wear underwent combined cataract extraction and epikeratophakia, followed by intensive amblyopia therapy. Follow-up ranged from 6 months to 7 years. In these monocularly aphakic children, three (16%) of the original 19 procedures failed and the tissue lenses were removed; two of these were repeated successfully. The success rate for the surgery was 86% (18/21) and 95% (18/19) for the patients. Postoperative visual acuity of 20/50 or better was achieved in six (33%) of the 18 patients with successful surgery. Another 11 (61%) achieved between 20/60 and 20/200. Postoperative astigmatism ranged between 0 and 4 diopters, with an average of 1.7 diopters. The results demonstrate that epikeratophakia can be successfully combined with cataract extraction in children with visually significant non-traumatic cataracts and that the majority of such children demonstrate an improvement in visual acuity.

Cataract Extraction↗

The correction of unilateral aphakia in children treated for orbital rhabdomyosarcoma.

The survival rate of children with localized orbital rhabdomyosarcoma is now greater than 90% 3 years after diagnosis as a result of advances in radiation and chemotherapy. Ninety percent of these children develop cataracts within 1 to 4 years after the completion of radiotherapy. The correction of aphakia in these children is complicated by the concurrent keratoconjunctivitis and dryness associated with radiotherapy. Three patients with a diagnosis of orbital rhabdomyosarcoma underwent treatment for uniocular cataract. Two of the patients were unable to use extended wear contact lenses. Both underwent epikeratophakia with poor results. One patient who had clinically significant ocular drying prior to cataract extraction underwent successful implantation of an intraocular lens as a primary procedure, with excellent visual results. Clinicians should be aware of the difficulties associated with contact lens wear and epikeratophakia tissue lenses in children who have had high doses of radiation for orbital rhabdomyosarcoma. Such patients are probably best served by primary intraocular lens implantation or by preservation of the posterior capsule at the time of cataract extraction to allow secondary lens implantation if contact lens wear is unsuccessful.

Aphakia, Postcataract↗

The acuity card procedure: longitudinal assessments.

Traditional methods of visual assessment in preverbal pediatric patients rely on refined but subjective measurement techniques. A standard ophthalmologic examination includes evaluation of a child's fixation patterns, with performance ranked on the basis of ability to fix and follow an object (F & F) or maintain central, steady fixation (CSM). In the hands of a skilled clinician, these evaluations are important for diagnosis and treatment. Documentation of quantitative changes in visual abilities of preverbal patients, however, has only recently become feasible. We began using the acuity card procedure in our pediatric clinical practice more than 3 years ago. This assessment, a modified version of the standard Forced-Choice Preferential Looking paradigm (FPL), provides quantitative evaluation of visual functioning in preverbal patients. The total number of patients assessed on one or more occasions exceeds 900. Of this group, we followed 83 patients with at least four acuity card evaluations on separate visits. Thirty of these patients, all with different diseases, have been evaluated with acuity cards on six or more visits. We found the information provided by the acuity card assessments extremely helpful in quantifying the developmental and therapeutic changes in vision, previously monitored only qualitatively.

Child, Preschool↗

Keratometry in children.

Corneal curvature was evaluated in 70 children by central keratometric measurements. The mean keratometric reading in each age group was seen to decline systematically from birth to about 54 months of age. The mean in the newborn-to-6-month-old group was 47.59 D; in the 12-18-month-old group it had decreased to 45.56 D. The cornea appears to stabilize at about 54 months, with an average reading of 42.69 D. Evaluation of 11 eyes diagnosed as having persistent hyperplastic primary vitreous revealed that eyes with this diagnosis generally have steeper corneas than normal eyes at any given age.

Analysis of Variance↗