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At least 73 records · Page 4Linked to original sources
PubMed1982

The validity of labeled parameters of aphakia-correcting soft contact lenses.

This study examines the validity of labeled parameters of aphakia-correcting soft contact lenses. The Nikon Projection Lensometer (NPL) and the Hydro-Vue Soft Lens Analyzer (HSLA) were used by two independent inspectors to measure 51 aphakia-correcting lenses. The contact lens power, diameter, and base curve were measured by each of the inspectors and compared to the labeled parameters. All parameter relations that were analyzed revealed that measurements made by the inspectors were not statistically different (p greater than 0.05) from each other and that their combined measurements were not statistically different (p greater than 0.05) from the labeled values.

Analysis of Variance↗
PubMed2002

Optical considerations in the contact lens correction of infant aphakia.

BACKGROUND: Correction of infant aphakia with conventional soft and rigid designs induces significant amounts of positive spherical aberration. METHODS: Different levels of positive spherical aberration were induced by rigid lenses positioned close to the eye. Visual acuity and depth of focus were measured for twelve young adult subjects. RESULTS: Positive spherical aberration acts to produce an increase in relative depth of focus, but because of the reduction of best visual acuity, there is a concurrent decrease in absolute depth of focus. As the spherical aberration increases, there is a progressive loss of best-corrected visual acuity. CONCLUSIONS: The correction of spherical aberration in contact lenses for infant aphakia provides the best theoretical optical conditions for normal ocular growth and visual development. We provide examples of the optimal aspheric surfaces to minimize spherical aberration in contact lenses for infant aphakes.

Adult↗
PubMed2005

Corneal perforation with secondary congenital aphakia in Peters anomaly.

PURPOSE: To describe two cases of secondary congenital aphakia in association with Peters anomaly. METHODS: Two infants were noted to have corneal opacification at birth. Each child was found to have Peters anomaly requiring corneal transplantation in 1 or both eyes. RESULTS: Each child underwent penetrating keratoplasty, revealing absence of the crystalline lens in 1 eye. Histopathologic evaluation of the corneal buttons was performed. Each specimen showed full-thickness corneal defects with lens remnants. CONCLUSIONS: Secondary congenital aphakia from corneal perforation should be considered in the presentation of severe Peters anomaly.

Aphakia↗
PubMed1997

Congenital aphakia in Peters' anomaly syndrome. A case report.

The authors report a case of congenital bilateral corneal opacities in which one of the eyes was enucleated because of malignant glaucoma and corneal perforation. Corneal defects and iridocorneal adhesion were found, but aphakia was the major pathologic ocular finding. The clinical picture and pathology study indicated this case as a Peters' anomaly presenting congenital aphakia.

Anterior Eye Segment↗
PubMed2005

Glaucoma in aphakia and pseudophakia in the Chennai Glaucoma Study.

AIM: To determine the prevalence of glaucoma among aphakes and pseudophakes in a rural population of southern India. METHODS: 3924 subjects aged 40 years or above underwent complete ophthalmic examination. Glaucoma in aphakia/pseudophakia was diagnosed using International Society of Geographical and Epidemiological Ophthalmology criteria in aphakic/pseudophakic people. RESULTS: 54 subjects (37 aphakes, 17 pseudophakes) (1.38% of 3924 subjects, 11.2% of 482 aphakes/pseudophakes) had glaucoma in aphakia/pseudophakia. Aphakia, age, intraocular pressure (IOP), pseudoexfoliation, and peripheral anterior synechiae greater than or equal to 180 degrees of the angle were risk factors for glaucoma on univariate analysis. On multivariate analysis, IOP and aphakia were independent risk factors for glaucoma. 39 people (72.22%) with glaucoma had normal IOP at presentation. None of the people with glaucoma were aware of the disease. Blindness in one or both eyes was seen in 12 subjects (10 unilateral and two bilateral)-that is, 22.22% of people with glaucoma in aphakia/pseudophakia. CONCLUSIONS: Glaucoma is an important cause of ocular morbidity among aphakes and pseudophakes in this rural population of south India. This glaucoma, responsible for unilateral or bilateral blindness in 22.2% of those affected, was entirely undetected in this study population.

Adult↗
PubMedDate not supplied

Visual results after primary intraocular lens implantation or contact lens correction for aphakia in the first year of age.

PURPOSE: The optimal role of intraocular lenses (IOLs) in infants remains a controversial topic. Some ophthalmologists advocate correction with a contact lens (CL), whereas others recommend an IOL correction. Our study compared visual acuity, ocular alignment, retreatment rate and binocular vision outcomes in children treated with these two methods at our clinic. METHODS: This study included 41 children with unilateral congenital cataract who underwent cataract surgery with posterior capsulorhexis and anterior vitrectomy, coupled with (IOL group, n=18) or without (CL group, n=23) primary IOL implantation. All infants underwent the first surgery during the first 12 months of their life and they were operated on in the period from 1994 to 1999. The mean age at surgery was 3.11+/-2.65 months (range: 28 days to 11 months). All patients were prescribed the same half-time reduced occlusion therapy. Good cooperation of the parents and good compliance with patching were the necessary conditions to include a patient in the study. Between January and February 2003, the final visual acuity and binocular vision outcomes were examined. RESULTS: The mean final visual acuity (logarithm of the minimum angle of resolution) of the operated eye was 0.43+/-0.33 for the IOL group and 0.58+/-0.39 for the CL group (p=0.14). The mean interocular difference in visual acuity was 0.22+/-0.29 for the IOL group and 0.56+/-0.31 for the CL group (p=0.042). The reoperation rate was 78% in the IOL group compared with 35% in the CL group (p=0.017). Esotropia or exotropia of more than 8 prism diopters were present in 55% of children (10/18) in the IOL group compared with 83% of children (19/23) in the CL group (p=0.039). CONCLUSIONS: We suggest that correction of aphakia after unilateral congenital cataract surgery with primary IOL implantation results in improved visual acuity, improved binocular vision outcome and less occurrence of strabismus, but a higher rate of complications requiring reoperation. Further studies with a larger pediatric patient group are necessary to confirm the optimal treatment of aphakia after unilateral congenital cataract extraction.

Aphakia, Postcataract↗
PubMed1991

Effects of aphakia on the geniculostriate system of infant rhesus monkeys.

The effects on the visual system of rearing rhesus monkeys with monocular aphakia, corrected with extended-wear contact lenses, were assessed with anatomical, electrophysiological and behavioral methods. The major finding was that the effects of the various treatments on the aphakic eye varied in degree depending upon the amount of focused pattern input received by the aphakic eye compared to its fellow eye. The behavioral, electrophysiological and anatomical assessments of the treatment effects on the aphakic eyes correlated closely with each other. Because this experimental paradigm is similar to current clinical procedures for treating human infantile monocular cataracts, it provides a nonhuman primate model for studying aphakia.

Animals↗
PubMed1982

[Binocular functions in unilateral aphakia with intraocular lens, contact lens, and spectacle correction (author's transl)].

The quality of binocular vision in unilateral aphakia was tested in presbyopic patients. 10 of them were corrected by a contact lens, 10 by an intraocular implant. Unilateral aphakic young patients were submitted to the same tests. In the young patients the unilateral accommodation proves to be the main obstacle to binocularity. In the presbyopics there is no difference between intraocular and contact lens correction as to the quality of binocular functions. Which one of these two alternatives for the correction of unilateral aphakia should be preferred in the individual case must, therefore, be decided upon by other criteria than binocular vision. The results with unilateral spectacle correction demonstrate that binocular vision cannot be achieved by compensation of aniseikonia alone.

Age Factors↗
PubMedDate not supplied

Neodymium:YAG pupilloplasty in pediatric aphakia.

An adequate pupillary aperture is required for accurate ophthalmoscopy and retinoscopy in pediatric aphakia. When pupillary miosis does not respond to pharmacologic dilation, optical iridectomy performed with a vitreous suction-cutting instrument under general anesthesia may be required. We report a 27-month-old aphakic child whose pupillary aperture was enlarged from 1 mm to 3.5 mm with neodymium (Nd):YAG pupilloplasty, following intramuscular sedation with meperidine, promethazine, and chlorpromazine. Removal of the laser chin rest and positioning of the patient on a table with adjustable height facilitated delivery of 140 applications at 2.5 to 4.3 mJ to the pupillary border. Levobunolol 0.5% controlled the transient posttreatment rise in intraocular pressure. We suggest that Nd:YAG pupilloplasty performed with sedation be considered as an alternative to intraocular surgery when pupillary miosis in pediatric aphakia does not respond to dilating agents.

Aphakia↗
PubMedDate not supplied

Photorefractive keratectomy for hyperopia and aphakia with a scanning spot excimer laser.

OBJECTIVE: To study the safety, efficacy, predictability, and stability of photorefractive keratectomy (PRK) for hyperopia and aphakia. METHODS: Fifteen eyes of 15 patients (mean age, 33 +/- 5.95 yrs) were enrolled in the study and divided into three groups. The first group was comprised of six eyes that had hyperopia ranging from +1.75 to +4.75 D; the second group had seven hyperopic eyes ranging from +5.00 to +9.75 D; the third group included two eyes of two aphakic patients. All eyes had PRK with a 193 nm argon fluoride excimer laser (Chiron-Technolas, Keracor 116) with a 10 Hz repetition rate and a fluence of 120 mJ/cm2. The total follow-up time in all eyes was 12 months. RESULTS: In the lower hyperopia group, 0% eyes were within +/- 0.50 D and 66% (N = 4) of eyes were within +/- 1.00 D of emmetropia with the other two eyes between +1.00 and +2.00 D at 1 year after PRK. In the higher hyperopia group, all eyes had at least +3.00 D of hyperopia at 1 year. In the aphakic group, both eyes achieved less than 50% of the target correction of +10.00 D at 1 year. Final uncorrected visual acuity ranged from 20/20 to 20/30 in the lower hyperopia group, 20/30 to 20/50 in the higher hyperopia group, and count fingers in the aphakic group. CONCLUSIONS: PRK is a relatively safe, stable, and effective procedure with reasonably good predictability for eyes with less than +5.00 D of baseline hyperopia, and poor predictability for eyes with more than +5.00 D of baseline hyperopia. PRK is ineffective in the correction of aphakia.

Adult↗
PubMed2000

Visual outcome after contact lens and intraocular lens correction of neonatal monocular aphakia in monkeys.

PURPOSE: A monkey model was used to evaluate intraocular lenses (IOLs) and extended-wear contact lenses (EWCLs) for the optical treatment of infantile aphakia in humans. Specifically, the relative effectiveness of EWCLs used alone and IOLs used in combination with EWCLs in preventing amblyopia was assessed. METHODS: A total of 33 rhesus monkeys was studied in this project, 24 assigned to experimental treatment groups and 9 to normal controls. Contact lenses made from a diffusing material or dyed opaque were placed on one eye at birth to simulate an infantile cataract. A unilateral lensectomy was then performed on the same eye within 2.5 weeks after birth. In 15 monkeys this was combined with implantation of an IOL. The eyes were left aphakic in the remaining 9 animals. EWCLs were used to adjust the optical correction of both aphakic and pseudophakic eyes to a near point (3-5 D). Opaque lenses were used to maintain daily part-time (approximately 70%) occlusion of the fellow eye. The primary outcome measure was grating acuity assessed with behavioral methods. Some animals were also assessed for acuity with sweep visually evoked potentials (VEPs) and for optotype acuity (Landolt C) with behavioral methods. RESULTS: Two of the animals with IOLs developed complications in the eye that precluded completion of the behavioral assessment protocol. Only behavioral outcomes obtained before or in the absence of surgical complications are presented. There was a developmental delay in the maturation of grating acuity in both eyes of both treatment groups. Normal adult levels of grating acuity were eventually achieved in the group treated with IOLs combined with EWCLs. Grating acuity was significantly poorer than normal in aphakic eyes treated only with EWCLs. Comparison of the two treatment groups revealed that pseudophakic eyes treated with multifocal IOLs had significantly better gating acuity than aphakic eyes. Assessments of optotype acuity and sweep VEP acuity revealed amblyopic deficits in both pseudophakic and aphakic eyes. CONCLUSIONS: Given an absence of serious postoperative complications, neonatal correction of aphakia with IOLs combined with EWCLs can lead to normal grating acuity in a primate model. Correction with EWCLs alone was not sufficient to produce normal grating acuity. Multifocal IOL treatments combined with EWCL provided a significantly better outcome than EWCL methods alone. However, neither IOL nor EWCL methods were able to prevent amblyopia as evaluated using behavioral testing with optotypes or with sweep VEPs.

Animals↗
PubMedDate not supplied

[Functional results of aphakia correction by different methods].

Functional results of aphakia correction by different methods (eyeglasses, contact and intraocular lenses) are compared. The difference of this study from previous is that it was carried out in a group of patients to whom these methods were prescribed in succession. The rightfulness of such an approach to evaluation of functional results of various methods for aphakia correction is dictated by the fact that the norm is a relative parameter for many ophthalmic ergonometric studies, and thus the investigations need to be standardized (e.g., investigations in the same patients). Comparison of the efficiencies of different methods demonstrated that the best results are attained with intraocular lenses.

Aphakia, Postcataract↗
PubMed2006

Difficult vertical diplopia studied by video-oculography in aphakia after contact lens use. A case report.

PURPOSE: To establish the utility of a video-oculography system (3D-VOG) in the diagnosis of a patient with difficult idiopathic vertical diplopia. CASE REPORT: We present a clinical case of an 87 year old female who was operated for glaucoma and cataract with the intracapsular technique in both eyes. She reported vertical diplopia with the use of contact lenses but not while using her aphakia spectacles. A complete ophthalmological study was carried out with special interest in the ocular motility study with 3D-VOG. RESULTS: Besides the hypertropia in lateroversion of the non-fixing eye, the video-oculography showed an incyclotorsion of the hypertropic eye, a fundamental factor for the differential diagnosis between bilateral superior oblique overaction and DVD or dissociated vertical divergence. Such a torsional strabismic deviation is very difficult to detail by other methods and is the important clue for diagnosis. The 3D-VOG made this diagnosis possible. CONCLUSIONS: The occurrence of a vertical diplopia with use of contact lenses, and not with spectacles, is explained by the limitation of ocular gaze movements with the aphakia spectacles which limitation is not found with the use of contact lenses, with diplopia appearing in the more extreme lateroversion possible with the contact lenses. The 3D-VOG system enabled us to analyze torsional movements in lateroversion that allowed the diagnosis of bilateral superior oblique overaction to be made.

Aged, 80 and over↗
PubMed1991

Epikeratoplasty for the correction of aphakia and keratoconus.

Epikeratoplasty is a form of refractive corneal surgery in which a lens made of human corneal tissue is sutured onto the deepithelialized surface of the patient's cornea. The indications of epikeratoplasty for the correction of aphakia and keratoconus are discussed. We also report the results of epikeratophakia for the correction of aphakia in eight eyes and for the treatment of keratoconus in five eyes.

Adolescent↗
PubMed1991

[Epikeratoplasty using lyophilized lenticles for the correction if aphakia in adults].

Fifty adult aphakic patients were treated surgically by epikeratoplasty. Forty-one eyes had posttraumatic aphakia including 26 eyes with corneal scars. Results are presented with a mean follow-up of 31 months. 64% of eyes achieved an uncorrected visual acuity of 0.2 or better. Best visual acuity was 0.2 or better in 92% of eyes (this percentage is similar to the preoperative figure) and 0.5 or better in 62%. 78% of eyes had a refraction within 3 diopters of emmetropia. 10% of eyes lost 2 or more lines of best visual acuity. Mean keratometric results and spheric equivalent of the refraction show stability of the procedure during a 2 year follow up period. These results confirm, that in selected patients, epikeratoplasty is a valid surgical alternative for adult aphakia.

Aphakia↗
PubMedDate not supplied

[Interlamellar refraction keratoplasty with central keratectomy of superficial corneal laminae in the correction of aphakia].

Interlamellar refraction keratoplasty with central keratectomy of superficial laminae of the cornea was used to correct aphakia in 15 patients and the results followed up for 2.5-7 years. This method permits a simultaneous refraction and optic transplantation of the cornea. Corneal refraction was enhanced by 7.2-14.8 diopters (the mean value 11.03 diopters). The technique is an extraocular one and therefore may be widely used for aphakia correction, particularly in cases with superficial opacities of the cornea.

Adolescent↗
PubMed1989

[Aniseikonia and unilateral aphakia].

The author submits the results of correction of unilateral aphakia which is a special type of anisometropia. For more than 500 examined patients with unilateral aphakia all those who had a refraction of the aphakic eye between 9.0 and 15.0 dpt were subjected to statistical analysis. The groups were classified with regard to the refraction of the aphakic eye. From the analysis ensues that optimal results of binocular vision are in the region round 12.0 and 13.0 dpt which is consistent with clinical results.

Adolescent↗
PubMed1986

A cost-effectiveness comparison of the intraocular lens and the contact lens in aphakia.

There is currently interest in the effectiveness and cost of the intraocular lens as compared with other methods of correcting aphakia following cataract extraction. We have undertaken a retrospective review of patients undergoing cataract surgery by the extracapsular method at Moorfields Eye Hospital during the period January 1982 to July 1983. From the total population we selected at random two groups of patients, having their aphakia corrected either by means of a contact lens or an intraocular implant. Patients under the age of 60 years and those with complicating illnesses were excluded from the study. Using case notes, we followed the sample patients from the time of referral until one year after the operation, and recorded a number of clinical and economic variables such as waiting time for operation, length of inpatient stay, incidence of per- and post-operative complications, number of follow-up visits, final visual acuity and (for the contact lens patients) waiting time for lens issue and average daily wearing time. We found that the visual acuities obtained, and the total costs to society, were similar for the two groups.

Aged↗