Contribution of the cornea and lens to the spherical aberration of the eye.
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Adult↗
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Results for “Aphakia, Postcataract”
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A note on the action spectrum of human rod vision.
A template representing the spectral distribution of the absorption coefficients of human rhodopsin was fitted to each of 59 individual action spectra of human rod vision (from one of three populations) by an optimization routine. Curve-fitting parameters included peak wavenumber, optical density at this wavenumber and (for those from the population neither aphakic nor constrained to ages where the standard lens transmissivity curve is supposed valid), density of the latter at the wavenumber of peak lens absorption. The average peak wavenumber of each population differed significantly from that of the other two. Either the standard curve of lens absorption (even with peak lens density as a curve-fitting parameter) is inappropriate for correcting the normal spectrum or the rhodopsins in the retinas of these populations do not all have identical wave-numbers of peak absorbance.
Adolescent↗
Scotopic spectral sensitivity of phakic and aphakic observers extending into the near ultraviolet.
Despite interest in ultraviolet (UV) damage and UV vision in lower vertebrates, there are few recent publications on human UV sensitivity. We obtained dark-adapted spectra from 4 aphakic and 5 normal eyes at 8.8 degrees off-fovea using the staircase method. Our measurements extended from 314.5 nm, near the limit imposed by corneal UV absorbance, to 650 nm. Phakic and aphakic sensitivities resembled the traditional rod spectrum at long wavelengths with a peak around 500 nm. However, aphakic subjects were much more sensitive than phakic observers below 420 nm. From phakic volunteers ranging in age from 22 to 43 we deduced lens absorbance which depressed sensitivity at 350 nm by approx. 4 log units (n = 7 phakic runs on 5 eyes, average age = 30) as expected. We show a maximum lens absorbance at 355-360 nm and a UV window in the lens absorbance at 315 nm consistent with data on optical density of human lenses.
Adult↗
Ultraviolet sensitivity of three cone types in the aphakic observer determined by chromatic adaptation.
Sensitivities at 5.5 deg off-fovea from the aphakic observer superimposed on orange, purple and blue fields were obtained to estimate short-, middle- and long-wavelength cone spectra respectively. The middle-wavelength mechanism had a visible wavelength maximum resembling a nomogram plus an UV sensitivity fitting a cis-peak. The short (and, to a lesser extent, the long) wavelength cone sensitivities are higher in the UV than expected.
Adaptation, Ocular↗
Peripheral vision and optokinetic nystagmus in children with unilateral congenital cataract.
The vision of cats which were monocularly deprived during early infancy, of kittens, and of young human infants shares two limitations: detection in the nasal visual field is far poorer than detection in the temporal visual field, and optokinetic nystagmus (OKN) is difficult to elicit when a pattern moves nasally to temporally. Here we report similar limitations on the vision of children who had a dense central cataract in one eye during early infancy. Extensive static perimetry with one of these children whose visual acuity was good in both eyes revealed that her threshold for detection all along the horizontal meridian was higher in her aphakic than in her normal eye, with this difference much more pronounced in the nasal visual field than in the temporal visual field. Three children who developed cataracts after 6 months of age showed no such discrepancy between thresholds in the temporal and nasal fields. We tested the symmetry of OKN in 12 children treated for unilateral congenital cataract. In every test of an aphakic (n = 4) or normal eye (n = 12), OKN occurred significantly more often when stripes moved temporally to nasally than when they moved nasally to temporally. In contrast, no asymmetry was observed in any of 13 children treated for traumatic cataracts incurred after 3 years of age. We conclude that children treated for unilateral congenital cataract, like young human infants and monocularly deprived cats, show asymmetric OKN and relatively poor detection in the nasal visual field.
Animals↗
Automated refraction in aphakia--II. Its repeatability and accuracy compared to conventional techniques.
The repeatability and accuracy of an i.r. electronic optometer (the Ophthalmetron) and of retinoscopy performed by experienced practitioners were studied in aphakia by testing a group of 17 patients three times with each method and by subjective techniques. The results show that the Ophthalmetron gives better repeatability than retinoscopy and that accuracy is marginally better for the sphere with the Ophthalmetron and for the cylinder power by retinoscopy when the mean of the three subjective results is taken as the true refractive value.
Adult↗
Using social epidemiology to understand who stays blind and who gets operated for cataract in a rural setting.
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Aged↗
Removal of silicone oil from aphakia: use of a self-sealing corneal incision.
PURPOSE: To report and illustrate a modified and simple technique for silicone oil removal from aphakic eyes. DESIGN: Interventional case series. METHODS: Eighteen eyes of 18 patients who once had pars plana vitrectomy and lensectomy combined with silicone oil tamponade underwent silicone oil removal using a self-sealing corneal incision. RESULTS: All of the 18 silicone oil removal procedures performed had clear corneal incisions, which did not require suturing. CONCLUSIONS: Silicone oil can be removed successfully from aphakia using the self-sealing corneal incision under local anesthesia.
Adolescent↗
Rate of axial growth after congenital cataract surgery.
PURPOSE: To evaluate the rate of axial growth after congenital cataract surgery. DESIGN: Prospective observational case series. METHODS: Rate of axial growth of 158 eyes (79 children < 10 years) undergoing surgery was correlated with age at surgery, laterality, and visual axis obscuration. After measuring axial length (AL) at each follow-up, the mean AL was calculated, adding the AL of all eyes divided by their total number. Rate of axial growth is the percentage difference between preoperative mean AL and mean AL at last follow up. The temporal profile of RAG is the difference between two consecutive mean ALs with respect to the previous reading. The follow-up period was 58.96 +/- 2.02 months. The student' paired t test and independent sample t test were applied. The main outcome measure was RAG. RESULTS: Rate of axial growth in children operated at < or = 1 year (23.5%) was significantly higher than in those at < or = 3 years (4.8%; P = .0001, confidence interval [CI] 1.05-3.2) and at < or = 10 years (4.3%; P = .0001, CI 1.3-3.1). In children operated at <or = 1 year, temporal profile of RAG was higher in the first 2 years after surgery. Rate of axial growth was higher in patients with unilateral pseudophakia at < or = 1 year (25.53%) than in age-matched patients with bilateral pseudophakia (18.50%; P = .001, CI -13 to -0.2). Rate of axial growth was negligible in children with visual axis obscuration in any group. CONCLUSION: Rate of axial growth is higher in children < or = 1 year and increases until the second year after surgery. Unilateral pseudophakia revealed accelerated growth compared with bilateral pseudophakia. Visual axis obscuration does not influence rate of axial growth.
Age Factors↗
Eye growth after pediatric cataract surgery.
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Aphakia, Postcataract↗
Changes in water content of high plus hydrogel lenses worn on an extended wear basis in a geriatric aphakic population.
PURPOSE: To investigate the water content of hydrogel lenses of relatively high plus power hydrogel lenses after 3 months extended wear and compare values with unused lenses. METHOD: Geriatric aphakic extended wear soft lens patients were fitted with one of four different brands of hydrogel lenses (A) Incanto 78 (Cantor and Nissel, UK), (B) PSL72 (Prospect lenses, UK), (C) ES70 (Ocular Sciences), (D) Proclear (Coopervision). After 3 months continuous wear the lens was removed and water content (WC) was determined at both lens surfaces using an Abbé refractometer. The water content was also measured for 40 unused lenses (+10 to +20D, 10 lenses per brand). RESULTS: One hundred and thirty-two lenses were checked after 3 months extended wear. Mean (+/-S.D.) WC values for front (f) and back (b) surfaces of worn and unworn lenses were, respectively, (A) Worn (n=45): f 73.2(4.13) b 73.8(4.33); unworn f 80.5(0.68) b 81.1 (0.80). (B) Worn (n=37); f 70.5(4.49) b 70.9 (3.89); unworn f 72.5(0.94) b 72.3 (0.89). (C) Worn (n=34); f 68.3(3.18) b 68.4(3.63); unworn f 70.6 (0.48) b 71.1 (0.55). (D) Worn (n=16); f 63.4(3.68) b 63.3(3.19); unworn f 60.9 (1.56) b 61.5 (1.92). There was a significant correlation between WC measured from front and back surfaces (p < 0.01). In worn A-C lenses, front surface WC tended to be lower than back surface WC. For lenses A and C at both surfaces the WC of worn lenses was significantly lower than unworn lenses (p < 0.05). For lens D, mean WC of worn lenses was significantly higher than unworn lenses (p < 0.05). In 80% of B lenses, surface WC of worn lenses were significantly lower than WC of unworn lenses (p < 0.05). There was no relationship between WC and lens power. CONCLUSION: On average, A and C lenses tended to desiccate but D lenses tended to swell as did 20% of B lenses. The front surface of worn lenses measured lower water content than the back surface suggesting the front surface is drier than the back. This apparent difference in water content between the surfaces could be an artefact emanating from differential rates of surface deposition.
Aged↗
Intraocular lens implantation during infancy: perceptions of parents and the American Association for Pediatric Ophthalmology and Strabismus members.
BACKGROUND: To determine whether a randomized clinical trial, the Infant Aphakia Treatment Study, comparing intraocular lens (IOL) implantation with contact lens (CL) correction for infants with a unilateral congenital cataract (UCC), is feasible by (1) ascertaining whether American Association for Pediatric Ophthalmology and Strabismus (AAPOS) members have equipoise regarding these two treatments and (2) evaluating the willingness of parents to agree to randomization. METHODS: All AAPOS members were surveyed in August 1997 and again in June 2001 regarding their use of CLs and IOL implants to correct infants vision after unilateral cataract surgery. In addition, a pilot study was begun in March 2002 to evaluate the safety of IOL implantation during infancy and the willingness of parents to randomize their children with a UCC to either IOL implantation or CL correction. RESULTS: In 1997, 89% of the 260 respondents reported that in the previous year they had treated at least one infant with a UCC, but only 4% had implanted an IOL in an infant <7 months old. Silsoft (Bausch & Lomb, Rochester, NY) CL correction was the preferred treatment choice for 84% of the respondents. In 2001, 21% of the 279 respondents had implanted an IOL in an infant. On a scale from 1 to 10 with 1 strongly favoring an IOL implant and 10 strongly favoring a CL, the median score was 7.5. Sixty-one percent of the respondents indicated that they would be willing to randomize children with a UCC to one of these two treatments. The main concerns about IOL implantation were poor predictability of power changes, postoperative complications, inflammation, and technical difficulty of surgery. The main concerns about CL correction were poor compliance, high lens loss rate, high cost, and keratitis. In our pilot study, 30 infants <7 months of age were evaluated at nine clinical centers for a visually significant UCC. Of 24 infants eligible for randomization, the parents of 17 (71%) agreed to randomization. CONCLUSIONS: Although most AAPOS members still favor CL correction after cataract surgery for a UCC, five times as many had implanted an IOL in an infant in 2001 compared with the number in 1997. Parents were almost equally divided in their preference for IOL implant versus CL correction. Given the relative equipoise of AAPOS members regarding these treatments and the willingness of more than two thirds of parents to agree to randomization, it seems likely that a randomized clinical trial comparing these two treatments could indeed be conducted.
Aphakia, Postcataract↗
Pediatric transscleral sutured intraocular lenses: efficacy and safety in 43 eyes followed an average of 3 years.
PURPOSE: To report longer term results of transscleral sutured intraocular lens (TSSIOL) implantation in a sizable cohort of aphakic children, who were not suitable for contact lens wear and lacked adequate capsular support for sulcus fixation of an intraocular lens. METHODS: Clinical outcome data were collated by retrospective review after surgery on 43 consecutive eyes in 32 aphakic children (mean age at implantation = 10 years; 33% < or = age 7 years). Outcome measures included visual acuity, postoperative refractive error, postoperative complications, and rate of reoperation. Follow-up averaged 37 months. RESULTS: Visual acuity improved after surgery in 70% (30) of operated eyes (in 69% or 22/32 children). Fifty-one percent (22/43 eyes) improved by two lines or more. No patient suffered a loss of acuity or exacerbation of preexisting amblyopia. Postoperative refraction was within +/-2.0 D of the predicted refraction in 93% (40/43) of eyes. Complications, with the exception of one eye (2%), were minor/transient and resolved in the first week after surgery. Complications included small hyphemas (7%, 3/43 eyes), vitreous hemorrhage (5%, 2/43 eyes), and ocular hypertension or hypotony (5%). Two eyes (5%) exhibited episodes of iris capture of the IOL optic, one of which (2%, 1/43) eventually necessitated reoperation for IOL exchange. No retinal detachments or other retinal complications were encountered. CONCLUSION: TSSIOL implantation appears to be a safe and effective method for correcting aphakia in pediatric eyes that lack adequate capsular support. Safety over a follow-up period longer than the average 3 years reported here remains to be determined. The surgery is more difficult to perform than capsular-bag or sulcus implantation and potentially carries greater risks.
Adolescent↗
Dramatic decrease in intraocular pressure following topical administration of cycloplegics in an aphakic child.
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Aphakia, Postcataract↗
Secondary intraocular lens implantation for pediatric aphakia.
PURPOSE: We sought to report the outcome of secondary intraocular lens (IOL) implantation in children. METHODS: This was a retrospective case review. RESULTS: A total of 77 eyes were identified. An average age at secondary implantation was 7.8 +/- 5.0 years, whereas the average age at primary cataract surgery was 1.5 +/- 2.6 years. Average follow-up was 2.7 +/- 1.9 years. Thirty eyes received a hydrophobic acrylic IOL implantation whereas 47 eyes received a PMMA IOL. The sites of fixation for implanted IOLs were as follows: anterior-chamber (n = 6), sulcus (n = 42), in-the-bag (n = 14), optic-capture (n = 6), piggyback (n = 4), and sutured (n = 5). Complications included clinically significant decentration, 4 (5.2%); visual axis opacification, 4 (5.2%); dislocation of the IOL, 2 (2.6%); and pupillary capture requiring repositioning of IOL, 1 (1.3%). Clinically significant decentration requiring surgical intervention was noted only in eyes with sulcus-fixated foldable IOLs (28.6%; 4/14). None of the 29 eyes with sulcus-fixated PMMA IOL implantation developed decentration. All the decentrations were in an inferior direction and occurred in eyes of male patients (P = 0.03). Eyes with an axial length of >23 mm were 4 times more likely to develop decentration if implanted with a sulcus-fixated foldable IOL when compared with eyes measuring <23 mm (P = 0.03). Postoperative geometric mean visual acuity was significantly better than preoperative visual acuity (P < 0.001). CONCLUSION: Secondary IOL implantation can be safely achieved in pediatric eyes. In-the-bag fixation of foldable IOLs is associated with a low rate of complications. Foldable lenses appear to have a higher rate of decentration than PMMA lenses when placed in the sulcus in eyes of myopic male patients.
Adolescent↗
Visual acuity development after the implantation of unilateral intraocular lenses in infants and young children.
PURPOSE: Intraocular lenses (IOLs) are now being implanted in infants and children with unilateral cataracts. However, there are no prospective data on the development of visual acuity after implantation. The aim of the present study was to prospectively assess the development of acuity in infants and preschool children who received IOLs or aphakic contacts lenses (CLs) after the extraction of a unilateral cataract. METHODS: Visual acuity was assessed using Teller Acuity Cards and/or crowded HOTV tests at target ages of 6 months, 1, 2, 3, and 4 years. RESULTS: Infants who received a primary IOL after extraction of dense congenital unilateral cataract (n = 5) showed improvement from an initially low mean visual acuity of 20/170 at 6 months to 20/85 at 12 months and 20/54 at 4 years. Visual acuity in the IOL group was similar to that of children who had good-to-excellent compliance with CL wear (n = 36; 4-year visual acuity 20/50) and better than that of children who had moderate-to-poor compliance (n = 11; 4-year visual acuity 20/135). Children who received IOLs after extraction of developmental unilateral cataracts by 6 months (n = 4; 4-year visual acuity 20/55) had visual acuity development similar to those treated with CLs (n = 5; 4-year visual acuity 20/55). Children who received IOLs after extraction of developmental unilateral cataracts after 1 year of age (n = 18) had better visual acuity than children those treated with CLs (n = 4) at 4 years of age (20/40 vs. 20/135). CONCLUSION: IOLs and aphakic CLs support similar visual acuity development after surgery for a unilateral cataract. IOLs may support better visual acuity development when compliance with CL wear is moderate to poor or when a cataract is extracted after 1 year of age.
Aphakia, Postcataract↗
Incidence and risk factors for glaucoma after pediatric cataract surgery with and without intraocular lens implantation.
PURPOSE: We sought to report the incidence of glaucoma in the eyes of children who underwent cataract surgery with and without intraocular lens implantation and to report the risk factors for developing glaucoma. METHODS: We undertook a retrospective review of pediatric cataract surgery charts, excluding traumatic cataract, aniridia and Lowe syndrome, steroid-induced cataract, lens subluxation, uveitis, retinoblastoma, radiation-induced cataract, retinopathy of prematurity, secondary IOL implantation, and patients with less than 1 month of postoperative follow-up. RESULTS: After pediatric cataract surgery, 10 (3.8%) of 266 eyes with primary intraocular lens implantation were diagnosed with glaucoma, whereas 8 (17.0%) of 47 aphakic eyes were diagnosed with glaucoma. During the initial analyses, we noted that all of the patients who developed glaucoma underwent cataract surgery when they were 4.5 months or younger. For all patients who underwent surgery during the first 4.5 months of their life, the glaucoma incidence was 24.4% (10/41) in children with pseudophakic eyes and 19.0% (8/42) in age-matched children with aphakic eyes (risk ratio=1.1, CI=0.7-1.9; P=.555). In patients who underwent surgery during the first 4.5 months of their life, the average age of the patients who developed glaucoma was not significantly different than those who did not develop glaucoma in pseudophakic eyes (2.0 months+/-1.4 vs. 1.9 months+/-1.0, P=.700) or aphakic eyes (2.6 months+/-1.5 vs. 1.4 months+/-0.9, P=.070). The corneal diameter of the eyes that developed glaucoma versus eyes that did not was not significantly different in patients with pseudophakic eyes (P=.860) or aphakic eyes (P=.254). Glaucoma was diagnosed in patients at an average of 8.6 months and 117.9 months after cataract surgery in those with pseudophakic eyes and aphakic eyes, respectively. CONCLUSIONS: Patients undergoing cataract surgery at an early age are at high risk for the development of glaucoma with or without an intraocular lens implant.
Age Factors↗
Long-term outcome of pediatric aphakic glaucoma.
PURPOSE: To determine the long-term outcome in pediatric patients with aphakic glaucoma. METHODS: A retrospective analysis of 130 patients diagnosed with aphakic glaucoma between 1969 and 2004 was performed. A total of 36 patients (55 eyes) were included in this study after excluding those who had cataract extraction after age 10 and those patients with other ocular conditions, systemic syndromes, traumatic cataracts, congenital glaucoma, or inadequate follow-up (less than 1 year). Outcome variables studied included visual acuity, number of medication changes required over the course of the follow-up, maximum number of medications used at a time for more than 6 months to control intraocular pressures, and surgical interventions required. Mean follow-up period was 18.7 years (range, 6.9-35 years). RESULTS: At the time of last follow-up, 54.5% of the patients had visual acuity 20/40 or better, 34.5% had 20/50 to 20/200, and 11% had acuity worse than 20/200. During the course of follow-up, 34% required 1 to 2 medication changes for controlling glaucoma, 33% required 3 to 5 medication changes, and 33% required 6 or more medication changes. Thirty-six percent of the eyes required a maximum of 1 to 2 medications for more than 6 months during the course of follow-up, 33% required 3, and 31% required 4 or more medications for controlling intraocular pressure. Of the 55 eyes, 15 eyes (27%) required surgical intervention. Six of the 15 eyes (40%) required 1 surgery, 8 eyes (53%) required 2 to 3 surgeries, and 1 eye (7%) required 4 to 6 surgeries. CONCLUSION: Patients with glaucoma after pediatric cataract surgery can have a good visual outcome although multiple medications and surgical interventions may be required to control the glaucoma.
Adolescent↗