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Physiopathological and clinical characteristics of accommodative strabismus are described. Medical treatment consists in correcting full cycloplegic refractive error. Bifocal lenses are useful in accommodative non refractive esotropia. Surgery aims to correct the residual esotropia with full optical correction.
The majority of patients with congenital esotropia in this consecutive series of 41 patients showed an increase in the angle of deviation when followed over an average of 3 months. The ages at the initial measurement and surgery, the cycloplegic refraction, and the clinical response to patching could not be used to identify those patients with a progressive increase in the quantity of the deviation. It was found, however, that if the preliminary surgical plan was adjusted (as it was in the majority of the patients in this series) to reflect the latest measurements obtained the day before surgery, a relatively high percentage of patients (90%) could be found to have achieved satisfactory alignment by the 6-week postoperative visit.
PURPOSE: To derive norms for monocular grating acuity and interocular acuity differences that are appropriate for clinical applications using the acuity card procedure (ACP) and Teller Acuity Cards (TAC). METHODS: Monocular acuities were measured in 460 children in 12 age groups between 1 month and 4 years. Inclusion criteria were term birth, good general health and normal development, normal eyes, and cycloplegic refraction within specific limits. Each child was tested by two ACP testers who were aware of TAC spatial frequency but not grating location during testing. RESULTS: Three monocular tests were completed in the first session in 99% of children. Median time to complete the tests of both eyes ranged from 3.2 to 8.4 minutes. Monocular acuity norms were calculated using 95% and 99% prediction limits. The new norms spanned higher spatial frequencies than the preliminary ACP norms between ages 1 month and 18 months but were similar between 24 and 36 months. The lower normal 2.5% limits were similar to lower limits of other normative studies. The interocular acuity difference was zero or 0.5 octave in 99% of subjects of all ages. Acuities obtained by the same tester on different days and by different testers on the same day were within 0.5 octave in at least 90% of subjects, comparable to previous studies. CONCLUSIONS: This study provides monocular acuity norms that are appropriate for clinical settings in which the ACP and TAC are used and should replace the preliminary ACP norms.
PURPOSE: To test whether eye growth changes produced by spectacle lens wear are mediated by changes in ciliary muscle tonus in chicks. METHODS: Because there is evidence that deprivation myopia is based on a local-retinal mechanism in the eye that probably remains functional after cycloplegia as well as after ciliary ganglion or Edinger-Westphal lesions, none of these treatments provides insight into whether accommodation tonus is also important in the control of axial eye growth. Because 6-hydroxy dopamine (6-OHDA) suppresses deprivation myopia, to isolate growth changes mediated by accommodation the authors injected 6-OHDA and paralyzed accommodation in addition (by corneal application of vecuroniumbromide). To quantify the state of cycloplegia, the abnormal pecking responses of cyclopleged chickens were studied. RESULTS: The authors found that cycloplegia could be maintained for 3 hours daily by corneal application of vecuroniumbromide. To ensure that visual exposure was restricted to the time period of cycloplegia, chickens were transferred to a 3-hour light/21-hour dark cycle. Control experiments showed that emmetropization was still functional under the changed light cycle. Strikingly, even with suppressed local-retinal growth control mechanisms (as indicated by the lack of deprivation myopia in a 6-OHDA injected group of chickens with occluders) and paralysis of accommodation, the eyes compensated for the defocus imposed by spectacles by changing their axial growth rates to be similar to those of eyes with functional accommodation. CONCLUSIONS: The findings show that the ciliary muscle and the activity of the iris sphincter muscle are not involved in emmetropization in chicks. If accommodation mediates the growth effects with lenses, it must happen via another pathway. Based on previous results, the authors propose that either the choroidal nerves from the ciliary ganglion to the choroid are important or that another yet unknown pathway from the Edinger Westphal nucleus to the eye transmits the necessary information.
OBJECTIVE: The authors report on the incidence of myopia and strabismus at 12 and 24 months postterm in a cohort of 190 premature infants with birth weights of less than 1251 g born in 1986 and 1987. METHODS: The neonatal and follow-up eye charts of a cohort of 190 premature infants were retrospectively reviewed. All 138 children who survived the neonatal period had at least one eye examination between day 28 and 42 of life that documented the presence and staging of retinopathy of prematurity (ROP) according to the International Classification of ROP. No infants received cryotherapy. Eye examinations conducted at 12 and 24 months postterm included assessment of vision, fundus, ocular motility, anterior segment abnormality, and refractive error. Eyes were refracted using cycloplegic retinoscopy. Strabismus was detected using the Hirschberg and cover tests. Eye reports were available for 80% (n = 110) at 12 months and 36% (n = 50) at 24 months. RESULTS: Fifty-three percent of the cohort exhibited ROP in the neonatal period; 12% of these progressed to stage 3 or 4 ROP. Myopia was observed in 16% (18/110) of the cohort at 12 months of age; 4.5% (5/110) measured more than 4.0 diopters of myopia. Children with birth weights of less than 751 g were 3.2 times more likely than those with birth weights between 751 and 1000 g and 10 times more likely than those with birth weights between 1001 and 1250 g to develop myopia in the first year of life. The likelihood of myopia at 12 months doubled with each increment in ROP stage. Of the 50 children reexamined at 24 months postterm, more than 80% demonstrated deteriorating vision. The incidence of myopia increased to 38% (19/50) overall, with 24% (12/50) of the cohort showing severe myopia. Astigmatism and anisometropia were highly correlated with severe myopia. Strabismus was seen with increasing frequency through the second year of life. All children with grade III or IV intraventricular hemorrhage in the neonatal period developed esotropia. CONCLUSION: This study emphasizes the significant roles of low birth weight, ROP, and intraventricular hemorrhage in the development of myopia and strabismus. Follow-up to 2 years of life is recommended given the demonstrated deterioration in our cohort.
Hyphema is a potentially sight-threatening sequela of blunt trauma. Delayed healing time, poor visual outcome, and complications such as corneal blood staining, anterior and posterior synechiae, increased intraocular pressure, and glaucomatous optic atrophy are most often associated with hemorrhage filling more than one half of the anterior chamber. Rebleeds are most likely 3 to 5 days following injury, in children, in blacks (particularly if they have sickle cell disease), and in persons who have ingested aspirin or other antiplatelet compounds. Treatment of hyphema is controversial, and medical therapy (antibiotics, cycloplegics, steroids, aminocaproic acid) should be tailored to suit the needs of each case. Intraocular pressure-reducing medications may be required if there is significant elevation of IOP. The affected eye should be protected with a shield, and follow-up examinations should be conducted as necessary. Both the anterior and posterior eye should receive careful assessment.
Using the Kowa laser flare cell meter, we investigated the relation between anterior chamber inflammation following phacoemulsification and posterior chamber intraocular lens implantation, and (1) iris color and (2) the use of 1% cyclopentolate hydrochloride for 1 week postoperatively. One hundred sixty eyes, randomized into either a cycloplegic or noncycloplegic group, and classified into four different iris color groups--blue, brown, green, and hazel--were studied. Eyes with brown irides had significantly more intense flare 2 weeks postoperatively than eyes with blue irides. Overall, postoperative flare tended to be related to the degree of iris pigmentation. Use of 1% cyclopentolate hydrochloride for 1 week postoperatively failed to decrease anterior chamber inflammation in any of the eyes.
Photorefraction is a promising technique for screening infants for amblyopiogenic defects, but currently used instruments often produce images that are difficult to interpret due to inaccurate control of the subject's fixation, to the narrow range (+/- 4 D) of the measurable error, to ill-defined crescent borders, and to chromatic aberration. A charge-coupled device (CCD) camera with near-infrared sensitivity connected to a computer with an image grabber for real-time equalization was devised to overcome the aforementioned problems. This binocular videorefractoscope (VRB) enables a dynamic and nondissociating refractive status and an ocular motility testing. Fixation and accommodative response are observed on-line and the strabismic angle is measured off-line. Arrays of infrared-emitting diodes with a variable eccentricity and position reveal sphere and/or cylinder errors (+/- 10 D; null interval, +0.00 to -2 in an 8-mm pupil diameter) as well as squint (> 5 prism diopters) and dioptric media opacities. The VRB was tested during noncycloplegic screening for amblyopiogenic defects in 212 3-year-old children. The findings were compared with the results of manifest and cycloplegic autorefractometry in a blind study. The VRB revealed a sensitivity of 81% and a specificity of 97%. In conclusion, the VRB can give a fast, noninvasive, and reliable evaluation of amblyopiogenic factors in infants.
219 normal infants aged 3 to 36 months were tested to investigate the relationship between the development of visual acuity and the change of refractive error. 17 infants were tested over a period of time. Visual acuity was assessed by Teller Acuity Cards (TAC), and refractive error was measured by an infrared video refractor (PR1000) without cycloplegics. The results were as follows. 1) The success rate of both tests in 3 to 6 month-old infants was higher than in infants aged 11 to 14 months and 23 to 36 months. 2) Visual acuity showed a rather slow development in infants aged 3 to 12 months. 3) With-the-rule astigmatism of 1 diopter (D) or more occurred with a high incidence in the 3 to 8 month old infants, and decreased with age. 4) The visual acuity in the infants with astigmatism was no different than in those without it. 5) The slow developmental curve of visual acuity measured in 3 to 12-month old infants was probably the result of psychological aversion to the TAC.
Two cases are presented in which unilateral transient angle-closure glaucoma accompanied occlusion of the central retinal vein. In both cases, the uninvolved eye had a wide-open angle and the involved eye demonstrated a marked anterior displacement of the lens-iris diaphragm. Short-term treatment with cycloplegics and carbonic anhydrase inhibitors resulted in a rapid and permanent deepening of both angles. The similarity of this picture to malignant glaucoma as well as possible causative factors is discussed.
The time-response effect of two currently used mydriatics, phenylephrine and tropicamide, were evaluated in 524 eyes. Four different types of dilating regimens were used: 2.5% phenylephrine, 10% phenylephrine, 0.5% tropicamide, and the combination of 2.5% phenylephrine and 0.5% tropicamide. The analysis indicated that the recovery from mydriasis occurs between 5.5 and 7.0 hours with 2.5% phenylephrine and at more than 7 hours with 10% phenylephrine. The 0.5% tropicamide induced rapid dilation, whereas the combined treatment, 2.5% phenylephrine plus 0.5% tropicamide, produced the largest maximum pupillary diameter. Tropicamide, alone or in combination, also produced a longer mydriatic effect, lasting more than 7.0 hours. The recovery from the cycloplegic effect of the mydriatics occurred between five and seven hours in the majority of patients, with tropicamide alone or in combination with phenylephrine requiring the most time to revert to normal ranges of accommodation. The findings in this study indicate that, in normal subjects, the recovery from the effect of mydriatic agents is longer than what is generally reported in the literature.
1. The eye is made up of three layers: the retina, uveal tract, and sclera, which is continuous with the cornea. 2. Drugs are used during surgery to achieve specific effects. Nonsteroidal anti-inflammatory drugs reduce irritation and maintain the dilation effect of cycloplegics and mydriatics. Viscoelastic substances protect the nonregenerative endothelial cells. 3. The risks involved with cataract surgery include hemorrhage in the anterior chamber, a tear in the posterior capsule, and damage to the endothelial cells and retina.
A red eye is a common complaint, often related to benign conditions. However, a red eye in conjunction with symptoms such as photophobia, pain, and decreased visual acuity is an important clue to a much more serious disorder. Iritis is one of these but is reversible with proper use of mydriatic and cycloplegic agents and corticosteroids. Heightened clinical suspicion is necessary for timely diagnosis. The examiner should be skilled in the use of a slit lamp or should refer the patient to an ophthalmologist for immediate evaluation. Once the diagnosis is made, treatment with topical corticosteroids is imperative. Close monitoring is required because overuse of corticosteroids has ominous side effects.
Despite the importance of lens power to ocular development, few data are available regarding infant crystalline lens parameters. Lens and corneal radii of curvature were measured in the horizontal meridian using a video-based keratophakometer, and refractive error was measured by cycloplegic retinoscopy in 19 out of 27 infants ranging in age from 3 to 18 months. The median refractive error was +1.50 D, and the median corneal power was 43.5 D. Using previously reported values for axial ocular dimensions, the median anterior and posterior lens radii of curvature were 8.7 and 5.6 mm, respectively, both substantially flatter than infant schematic eye values. The median equivalent refractive index of the lens was 1.49, considerably higher than previous reported schematic values for infants or children. There was a significant reduction in hyperopia with age (r = -0.47, P = 0.043), but no age-related trends in lens or corneal radii of curvature, suggesting that calculated values for lens power and equivalent index may undergo substantial decline with age during early childhood development as axial length increases. Most of the decrease in lens power (75%) may be due to decreases in equivalent index rather than to flattening of the surface radii of curvature. Videophakometry appears to be a feasible and useful technique for documenting the role of the crystalline lens in infant ocular development.
UNLABELLED: Conventional PMMA intraocular lenses (IOLs) have been shown to restore vision successfully after cataract surgery, but have been associated with complications such as decentration, destruction of intraocular tissue, and posterior capsule opacification. Expansile IOLs based on cross-inked polyhydroxyethylmethacrylate (PHEMA) also undergo chemically induced hydrolysis, polymer leaching and gel fragmentation. The focus of this research is to prepare and characterize hydrogel IOLs prepared from PVP using gamma-irradiation. METHODS: Hydrogels were prepared from aqueous solutions of PVP by free radical polymerization as a function of gamma-irradiation dose (0.5 x 106 to 2.5 x 106 rad), PVP concentration (4% to 16% w/v), molecular weight (MW) (10 x 103 to 360 x 103 Da), and blending with low and high MW PVP. Viscometric analysis, swelling characterization studies, and polymer leaching studies were carried out to access network formation. In addition changes in lens geometry in an animal model were measured in response to cycloplegic eyedrops. RESULTS: Cross-linking efficiency was greatest with an initial MW of 360 x 103 Da and lowest with an initial MW of 10 x 103 Da. The time to reach equilibrium from the glassy state and the degree of swelling in saline decreased with increasing gamma-irradiation dose and increased with concentration of PVP and blending of low and high MW PVP. The equilibrium water content ranged from 90 to 98% (w/w). Eighty-five percent of the equilibrium dimensions could be achieved within 90 min. Gravimetric analysis and HPLC indicate that the amount of PVP that is not incorporated into the network ranges from 0.25% to 6% (w/w). This was inversely related to the gamma-irradiation dose. The MW of the leached samples was estimated to be greater than 10 x 103 Da in all cases. CONCLUSIONS: PVP hydrogel IOLs prepared by gamma-irradiation have advantages in terms of chemical stability, high water content, and ease of preparation. They may not need further purification or sterilization prior to implantation. In addition, they may allow for accommodation. No comments can be made regarding the biocompatibility, long-term stability, or optical quality at this time.
The postoperative course after cataract surgery can be complicated by the formation of severe fibrinous membranes, especially in cases with previous goniotrepanation, after syn echiolysis, iridotomy or iris suturing, and in patients with diabetes or uveitis. This study retrospectively analyzes the efficacy of intraocular tissue plasminogen activator (tPA) for fibrinolysis in these conditions commonly considered as contraindications to tPA therapy. When antiinflammatory therapy was unsuccessful in lysing fibrinous membranes, 10 micrograms of tPA (Actilyse) was injected into the anterior chamber following the first postoperative day (n = 15). In addition, topical corticosteroids and cycloplegics were given postoperatively. Lysis of the fibrinous membranes was achieved in all patients. However, in three cases lysis was incomplete or recurred. Complications of intraocular tPA therapy consisted of mild hyphema (n = 1) and transient dysfunction of the corneal endothelial cells (n = 2). In conclusion, the results suggest intraocular low-dose tPA as an effective approach for the treatment of severe fibrinous membranes after cataract surgery even in high-risk patients.
In this study, we report our clinical experiences and results in performing 193-nm argon fluoride excimer laser phototherapeutic keratectomy (PTK) on 48 eyes of 45 patients with various pathology in the anterior one-third of the cornea, including leukoma, stromal dystrophy, anterior basement membrane dystrophy, and Salzmann's nodular degeneration. The VISX model 20/20 laser was used to ablate the anterior stroma to variable depth, dependent upon pathology. Patients were followed for a minimum of 1 year. Per an FDA-approved protocol vision, refraction, comfort, clarity, rate of reepithelialization, and complications were monitored. Seventy-two percent of patients undergoing excimer laser ablation for visual recovery had documented improvement in Snellen acuity. For the same period, 70% of those patients who were symptomatic prelaser were noted to be more comfortable. Corneal clarity improved in 35 of 48 eyes (73%), remained stable in nine (19%), and worsened in four (8%). Complications arose in 8% and included recurrence of herpetic keratouveitis, episcleritis, and an attack of narrow angle glaucoma secondary to cycloplegic agents. Delayed reepithelialization, >7 days, was noted in nine patients (19%). All complications were successfully treated medically. Excimer PTK appears to be a valuable addition to our therapeutic armamentarium for the treatment of superficial stromal opacification and surface irregularity.
BACKGROUND: Paremyd, consisting of a combination of 1.0 percent hydroxyamphetamine and 0.25 percent tropicamide, is a commercially available eyedrop used clinically for diagnostic mydriasis. This study sought to determine if one drop of Paremyd is equally effective and tolerable as the traditional combination of one drop each of 2.5 percent phenylephrine and 0.5 percent tropicamide. METHODS: A prospective, double-masked, randomized, cross-over study was conducted in 60 normal volunteers ranging from age 20 to 35 years (mean 24.3 years). Twenty-two subjects (36.7 percent) were male, and 32 subjects (53.3 percent) had brown irides. Pupil diameter, amplitude of accommodation, distance and near visual acuity, and subjective comfort of eyedrop instillation were assessed for 8 hours following drug instillation. RESULTS: Significantly more subjects (p < 0.05) experienced adverse ocular symptoms with the tropicamide plus phenylephrine (TP) combination than with Paremyd (P). There was no statistically significant (p > 0.05) difference in mydriatic response between TP and P. During the first hour, however, TP and P demonstrated significant (p = 0.001) differences in cycloplegic effect. CONCLUSIONS: Paremyd appears to be as effective a mydriatic as TP, but with greater comfort on instillation. Paremyd has less effect on accommodation.