ABSTRACT
Astigmatism is a common refractive error found in a large percentage of patients who wear contact lenses. Since 1979, soft toric contact lenses have been available to correct for refractive astigmatism. Most of the original soft toric lenses had the correcting optical strength on the front surface, but more recently, soft toric lenses have been designed with the correcting optics on the back surface of the lens. Back-surface toric lenses provide much more stability, comfort, and increased visual acuity. There have been a number of research articles involving soft toric contact lenses that discuss various aspects of back-surface toric lenses and their advantages over front-surface toric lenses. These advantages are presented and discussed in this paper.
Subject(s)
Astigmatism/therapy , Contact Lenses, Hydrophilic , Equipment Design , Humans , Optics and PhotonicsABSTRACT
The most common complication of extracapsular cataract extraction is posterior capsule opacification, which appears to result from the proliferation of anterior lens epithelium onto the posterior capsule. The presence of a posterior chamber intraocular lens has been shown to decrease the incidence of posterior capsule opacification, possibly by a barrier mechanism. This retrospective clinical study compares the effect of two different lens designs (with and without a laser ridge) on posterior capsule opacification requiring Nd:YAG laser posterior capsulotomy. Twenty-one of 101 patients (20.8%) with nonridged lenses required Nd:YAG laser posterior capsulotomies versus 13 of 86 patients (15.1%) with ridged lenses. Although these data showed a clinical benefit from using a ridged lens, no statistical difference in the incidence of posterior capsulotomy was noted. Further evaluation of capsular-optic surface apposition is needed.
Subject(s)
Lens Capsule, Crystalline/pathology , Lens, Crystalline/pathology , Lenses, Intraocular/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Follow-Up Studies , Humans , Laser Therapy , Lens Capsule, Crystalline/surgery , Middle Aged , Prosthesis Design , Retrospective StudiesABSTRACT
We reviewed soft toric contact lens fitting success in 100 eyes that required greater astigmatic correction than spherical power correction. We found a significantly greater rate of success with lenses having back surface cylinder correction than lenses with front surface cylinder. When back surface optics are used to correct astigmatism with soft toric lenses, the success rate approaches that obtained in random studies of soft lens fitting success.
Subject(s)
Astigmatism/therapy , Contact Lenses, Hydrophilic , Follow-Up Studies , Humans , Optics and Photonics , PrognosisABSTRACT
This retrospective study reviews the time interval between extracapsular cataract extraction with posterior chamber intraocular lens placement and neodymium (Nd):YAG laser posterior capsulotomy relative to the age of the patient at the time of cataract surgery. Two hundred thirteen consecutive laser procedures involving eyes that had had extracapsular cataract extraction within 6 years were reviewed. We found that there was an upper limit on the time interval from extracapsular cataract extraction to Nd:YAG posterior capsulotomy for all patients eventually requiring a Nd:YAG capsulotomy. This time limit appeared to be directly proportional to the age of the patient at the time of his or her cataract surgery: the older the patient at the time of surgery, the longer the period the patient was at risk for requiring a capsulotomy. Beyond this time limit, the likelihood that an Nd:YAG capsulotomy would be required was less than 2.5%. The prolonged period of risk for elderly patients may be related to an age-related decline in lenticular hyperplasia.
Subject(s)
Cataract Extraction , Lenses, Intraocular , Adult , Age Factors , Aged , Humans , Laser Therapy , Middle Aged , Retrospective Studies , Risk Factors , Time FactorsABSTRACT
Two hundred sixty eyes of 195 patients having extracapsular cataract extraction (ECCE) with insertion of a posterior chamber intraocular lens were studied retrospectively. Of these cases, 160 eyes had preexisting glaucoma while 100 had no ocular pathology except for cataract. Intraocular pressure decreased significantly after ECCE in both groups and slowly returned to baseline within two years. The average postoperative visual acuity was better in the control group than in the glaucoma group. Patients with glaucoma were controlled with less medication after surgery. We believe that ECCE with insertion of a posterior chamber intraocular lens can be safely performed in glaucoma patients and has a beneficial effect on the control of glaucoma.
Subject(s)
Cataract Extraction , Cataract/complications , Glaucoma, Open-Angle/complications , Aged , Female , Humans , Intraocular Pressure , Lenses, Intraocular , MaleSubject(s)
Cataract/diagnosis , Photic Stimulation/methods , Cataract/physiopathology , Humans , Visual AcuityABSTRACT
We describe an alternative glare test using a simple penlight. When the glare and decrease in vision created by the penlight were compared on Snellen chart recordings, 92% of eyes within 20/50 or less visual acuity were no longer able to see even the 20/200 Snellen figure. This penlight test is suggested as an adjunct to standard Snellen testing in the evaluation of the cataract surgery patient.
Subject(s)
Cataract/physiopathology , Vision Tests , Vision, Ocular , Aged , Evaluation Studies as Topic , Humans , Light , Lighting , Scattering, Radiation , Vision Tests/instrumentation , Vision Tests/standards , Visual AcuityABSTRACT
The records of 74 patients with primary angle-closure glaucoma were reviewed. Cataract formation in 103 eyes treated with argon laser were compared with eyes in an age- and sex-matched, randomly-selected control group to determine whether cataract formation was hastened by laser iridotomy. Twenty-three percent of eyes in the study group showed development of cataracts 29.9 months after laser treatment. This did not differ from the incidence of cataract formation (20%) in the same group before laser exposure (P = .357) and was significantly lower than the 49% incidence of cataracts observed in the age-matched control group (P less than .001). These data demonstrate the safety of laser iridotomy in the treatment of narrow-angle glaucoma.
Subject(s)
Cataract/etiology , Glaucoma/surgery , Iris/surgery , Laser Therapy/adverse effects , Adult , Aged , Aged, 80 and over , Cataract/pathology , Humans , Middle Aged , Reference Values , Retrospective StudiesABSTRACT
Cataract extraction in children has undergone dramatic changes during the past 20 years, largely as a result of technologic advances. The neodymium: yttrium aluminum garnet (Nd:YAG) laser has indirectly brought the surgical technique full circle. The posterior capsule may be preserved at surgery and treated successfully with the Nd:YAG when necessary. In 16 such cases reported here, 11 patients with congenital and five with acquired cataracts all had improved vision after treatment with the Nd:YAG laser. The youngest patient was aged four years. The safety of Nd:YAG laser therapy is supported by this study.
Subject(s)
Cataract Extraction , Laser Therapy , Adolescent , Child , Child, Preschool , Humans , Visual AcuityABSTRACT
Intraocular lens (IOL) power data have been compiled in tabular format as a function of axial length measurements, corneal powers, and desired refractive errors. The table is presented to assist the clinician in performing IOL power estimates and as an independent source for checking preoperative IOL power calculations. Ophthalmologists who do not own a personal computer will find the lens power table a valuable adjunct to their present repertoire of analytical skills.
Subject(s)
Lenses, Intraocular , Forecasting , Humans , Models, Theoretical , Optics and Photonics , Refraction, Ocular , SoftwareABSTRACT
Pupillary block occurred in six patients with anterior chamber intraocular lens implants. After medical therapy failed, the Nd:YAG laser was used to break the hyaloid face in the pupillary and iridectomy apertures. Iridotomies were also produced at the sites of bulging iris. Following laser treatment the anterior chambers deepened and there were no further signs or symptoms of pupillary block. The Nd:YAG laser proved to be a useful treatment for pseudophakic pupillary block.
Subject(s)
Cataract Extraction/adverse effects , Glaucoma/surgery , Laser Therapy , Lenses, Intraocular/adverse effects , Aged , Female , Glaucoma/etiology , Humans , Male , Postoperative Complications , PupilABSTRACT
Ten cases of combined strabismus surgery and intraocular lens implantation were reviewed to determine if there were increased risks and complications. A review of these cases revealed the contrary was true; i.e., there were no complications arising from the combined surgery and there were benefits in the decreased hospitalization and operative time, less mental trauma, and improved muscle surgical outcome. From these results, we conclude that combined intraocular lens and strabismus surgery is efficacious and indicated in patients with strabismus and cataracts or aphakia.
Subject(s)
Lenses, Intraocular , Postoperative Complications/etiology , Strabismus/surgery , Combined Modality Therapy , Follow-Up Studies , Humans , Visual AcuityABSTRACT
Posterior capsulotomy is occasionally performed at the conclusion of extracapsular cataract extraction because of the high incidence of secondary membrane formation. Using a Nd:YAG laser we successfully performed posterior capsulotomies on 16 children who developed secondary membranes following extracapsular cataract extraction in which the posterior capsule was left intact. Eleven patients had congenital cataracts and five had acquired cataracts. The youngest patient was four years. All had improvement in visual acuity. Preserving most of the posterior capsule provides additional support to the eye and has been associated with a decreased incidence of cystoid macular edema. It also allows secondary implantation of a posterior chamber intraocular lens in the future.
Subject(s)
Laser Therapy , Lens Capsule, Crystalline/radiation effects , Lens, Crystalline/radiation effects , Adolescent , Cataract Extraction , Child , Child, Preschool , Humans , Membranes/radiation effects , Visual Acuity/radiation effectsSubject(s)
Contact Lenses, Hydrophilic , Adult , Aphakia/therapy , Astigmatism/therapy , Equipment Design , Humans , Hyperopia/therapy , Myopia/therapyABSTRACT
A BASIC program to calculate intraocular lens power and refractive errors using previously derived equations is presented. The program was written for the IBM PC and PCjr computers with an emphasis on clinical usefulness. Program features include a comparison of refractive and axial length predictions of secondary implant power and velocity compensation for axial length measurements made on aphakic patients. Equation specification by input variable selection and automatic averaging of keratometer readings make the program highly efficient.
