Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Aphakia”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1985

The influence of aphakia and vitrectomy on experimental retinal toxicity of aminoglycoside antibiotics.

To study the effect of lens and vitreous surgery on the dose threshold of aminoglycoside-induced retinal toxicity, we performed extracapsular lens extraction (Group 1) or lensectomy and vitrectomy (Group 2) on Dutch Belted rabbits. A single dose of amikacin or gentamicin ranging from 100 to 4,000 micrograms was administered intravitreally. Retinal toxicity was examined by light and transmission electron microscopy seven days after injection. Both groups showed retinal toxicity after 400 micrograms of gentamicin or 1,500 micrograms of amikacin, doses identical to those causing toxicity in intact, phakic rabbit eyes. Thus, neither surgical procedure increased the toxic threshold of injected aminoglycoside. Given the accelerated aminoglycoside clearance reported in aphakic eyes, these findings imply that the mechanism of aminoglycoside toxicity may be related to peak drug concentration rather than duration of tissue exposure.

Aminoglycosides↗
PubMed1978

Secondary lens implantation in aphakia: visual results and complications.

We reviewed 70 cases that had undergone secondary lens implantation. The lenses used included 34 Medallion and 36 Choyce Mark VIII lenses. A 20/40 or better vision was present in 74.3% of the cases before implantation, and could be achieved postoperatively in 95.7% of the cases. Corneal changes, i.e. endothelial corneal dystrophy and induced astigmatism, were not noted in cases where Choyce Mark VIII lenses were used. Cystoid macular edema occurred in three cases where surgery followed an intracapsular cataract extraction (5.3%).

Adult↗
PubMed1978

Prolonged-wear contact lenses in aphakia.

While prolonged wear of contact lenses is possible for the aphakic patient, careful consideration must be given to patient selection and to the potential complications of such use. Currently available lenses are far from ideal and, if used at all, must be carefully monitored. The newer lenses, specifically designed for extended wear, more closely fit our needs. Several manufacturers are testing their devices under strict FDA supervision. FDA guidelines dictate a minimum of two years follow-up before a determination will be made as to which lenses are safe and effective enough for prolonged wear in aphakic eyes.

Adult↗
PubMed1979

Physiology of monocular aphakia.

The refraction of the unilateral aphakic patient has been aided by recent improvements in the ophthalmometer. New techniques simplify retinoscopic assessment of the patient. Choice of the type of correction, ie, spectacle, contact lens, contact lens-spectacle combination, or intraocular lens, depends on several factors. One factor is image size difference in aphakic and phakic eyes, particularly if removal of a second cataract is not imminent and vision is good in both eyes. Simple approaches that allow approximate size correction and effective restoration of binocularity are described. The current status of correction of vision in unilateral aphakic infants and young children is also discussed.

Adult↗
PubMed1980

Corneal response to extended wear of CAB contact lenses in aphakia.

We studied 41 aphakic eyes in 30 patients who had been wearing CAB (cellulose acetate butyrate) contact lenses on an extended basis. Patients were 51 to 81 years old and averaged 14.3 months of wearing time. Visual acuity was very good. Pachometry measurements ranged from 0.42 mm to 0.66 mm and averaged 0.550 mm. This compares favorably with data in the literature on corneal thickness seen with routine use of PMMA or hydrogel lenses or with extended wear of hydrogel lenses. Corneal thickness was also compared with unoperated fellow eyes and eyes using CAB lenses on a daily basis only.

Aged↗
PubMed1981

A prospective study of the use of hyperopic epikeratophakia grafts for the correction of aphakia in adults.

The results of a prospective clinical study of hyperopic epikeratophakia grafts for the visual rehabilitation of aphakic patients are presented. Visual acuity data are given for 21 aphakic patients who have been followed for up to six months postoperatively. With spectacle overrefraction, on the average, patients were within three lines of their preoperative potential vision at three months postoperative and within two lines at six months postoperative. Three months postoperatively, two patients achieved visual acuities of 20/20, and 57% had 20/40 or better with spectacle overcorrection. Six months postoperatively, three patients achieved best-corrected visual acuities of 20/20, and 80% had best-corrected visual acuities of 20/40 or better.

Adult↗
PubMed1982

Epikeratophakia -- the surgical correction of aphakia. Update 1981.

Epikeratophakia grafts used to rehabilitate vision in adult monocular aphakic patients intolerate of contact lens correction or not candidates for IOLs were studied prospectively. Thirty-two patients who entered this study between its inception in February 1980 through February 1981 were followed for at least eight months. Patients with normal visual potential before surgery had average visual acuities with spectacle overcorrection of 20/50 at four months, 20/40 at eight months, and 20/30 at one year. Few long-term complications were seen. Empirical modification of the lathing process has decreased the undercorrection from the 5.5 diopters seen in the early patients to the 1.0 diopter seen in the more recent patients. Problems with predictability are related to the behavior of preserved corneal tissue during the lathing and the healing of these lamellar grafts. This procedure is intended for aphakic patients of whom IOL and contact lens correction is not possible.

Adult↗
PubMed1983

Epikeratophakia: the surgical correction of aphakia. Update: 1982.

Sixty-five epikeratophakia procedures have been performed in 63 patients; visual acuity data have been tabulated on 31 patients with 4 to 30 months follow-up. Patients with more than a year of follow-up showed stable keratometry readings. Early patients achieved 70% of the predicted dioptric correction; more recent patients have achieved 87% with improvements in the lathing procedure, tissue handling, and surgical technique. Visual acuities improve with time. At any given time after surgery, acuities measured with a hard contact lens are better than those measured with spectacles; the decrease in spectacle acuity is probably a result of irregular refraction at the graft surface. The gap between contact lens and spectacle acuity decreases with time. A number of patients achieve postoperative visual acuities better than their preoperative acuities, and most achieve final spectacle acuities within a line or two of their preoperative acuities.

Aphakia, Postcataract↗
PubMed1985

Silsoft extended wear contact lenses in pediatric aphakia.

Fifty pediatric aphakic patients, ranging in age from 7 days to 11 years, were fitted with the Silsoft extended wear contact lens. Compared to other extended wear lenses, the Silsoft lens has several advantages. These include easier handling, a less traumatic fitting procedure for the child, the use of fluorescein for evaluation of the lens-cornea relationship and a low loss rate. This lens appears to be safe, with no permanent adverse effects on the cornea.

Aphakia, Postcataract↗
PubMed1987

Epikeratoplasty. The surgical correction of aphakia, myopia, and keratoconus.

Thirty-five patients have had 39 consecutive epikeratoplasty procedures (12 adult aphakic, 9 pediatric aphakic, 12 myopic, and 6 keratoconic eyes) by the same surgeon, using commercially prepared lenticules. The lenticule remained totally clear in 85% of eyes. Two lenticules were removed due to infection and scarring; four lenticules had minimal scarring and did not require removal. Spectacle-corrected acuity was worse than one line from the preoperative spectacle-corrected acuity in 58% of the adult aphakic eyes; however, 75% were 20/50 or better postoperatively. Fifty percent were within 2 diopters (D) of emmetropia and 92% within 3 D. All pediatric aphakic patients showed an improvement in best-corrected acuity, and 83% of eyes at 6 months were within 2 D of emmetropia; by 1 year a 3.4-D average myopic shift had occurred. Two of the six eyes (33%) using the original myopia technique were within 2 D of emmetropia, whereas five of the six eyes (83%) with the current technique are within this range. Spectacle-corrected acuity in the entire current myopia group has either improved by one or more lines or has remained unchanged. Five of the six keratoconic eyes had 20/40 or better spectacle-corrected and 20/25 contact lens-corrected acuity postoperatively; average corneal flattening was 6 D. Persistent epithelial defect and irregular astigmatism were the principal factors in delay in visual recovery.

Adolescent↗
PubMed1988

Surgical therapy of chronic glaucoma in aphakia and pseudophakia.

Most glaucoma surgical procedures are less successful in aphakic or pseudophakic eyes. The authors reviewed 91 consecutive initial glaucoma procedures in aphakic patients from 1979 to 1986 to determine successful outcomes and complications. Success was defined as an intraocular pressure (IOP) of at least 30% below the preoperative value and less than 21 mmHg, less than 2 lines of Snellen acuity loss, and no further surgical intervention. At 9 months, success rates were: trabeculectomy, 4 of 15 patients; cyclodialysis, 3 of 20 patients; neodymium:YAG (Nd:YAG) cyclophotocoagulation, 1 of 8 patients; cyclocryotherapy, 9 of 22 patients; anterior chamber tube shunt (Schocket procedure), 3 of 6 patients; and argon laser trabeculoplasty, 2 of 20 patients. Severe complications included phthisis bulbi in 11% of cyclocryotherapy and severe visual loss in 20% with cyclodialysis and 14% with cyclocryotherapy. Results confirm the difficulty of surgical therapy in these patients.

Aged↗
PubMed2003

Selective loss of dopaminergic neurons in the substantia nigra of Pitx3-deficient aphakia mice.

Dopaminergic (DA) neurons in the ventral midbrain nuclei, substantia nigra pars compacta (SNc, A9) and ventral tegmental area (VTA, A10), play important roles in the control of movement, emotion, cognition, and reward related behavior. Although several transcription factors have been shown to be critical for midbrain DA neuron development, there has been no report of factor(s) that differentially regulate individual DA neuronal groups. Based on its highly restricted expression in the SNc and VTA in the brain, we hypothesize that the homeobox transcription factor Pitx3 may critically regulate the development of ventral midbrain DA neurons. In this study, we report that in Pitx3-deficient ak/ak mice, DA neurons in the SNc and the nigrostriatal pathway fail to develop properly, and DA levels are reduced to 10% of the wild type mice in the dorsal striatum. On the contrary, A10 neurons are intact in ak/ak mice and DA levels within their projection areas are not affected. This region-specific defect was already evident in newborn mice, suggesting that the defect had occurred during the early stages of mouse development. Taken together, our results indicate that Pitx3 is the first known transcription factor that may critically and selectively control proper development of A9 DA neurons and the nigrostriatal pathway. This observation is of great importance in understanding the mechanisms of DA neuron development and may also help us to understand the mechanism of selective degeneration of A9 DA neurons in Parkinson's disease and to devise novel therapeutic approaches for the disorder.

Animals↗