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We report 3 cases of bilateral piggyback lens implantation in which late hyperopic shift occurred associated with Elschnig pearl formation in the peripheral interface between the 2 lenses.
PURPOSE: To evaluate the efficacy and safety of steepening the flatter meridian with laser in situ keratomileusis (LASIK) to correct hyperopic compound astigmatism using the Schwind-Keratom laser with the MultiScan System and the active tracking system for centering the ablation. SETTING: Instituto Barraquer de América, Bogotá, Colombia. METHODS: From June to December 1997, LASIK was performed in 111 eyes to correct congenital hyperopic compound astigmatism. Preoperatively, the mean spherical equivalent was +2.58 diopters (D) (range +1.50 to +3.50 D) in 37 eyes (low dioptric group), with a mean sphere of +3.66 D (range +1.75 to +5.50 D) and a mean cylinder of -2.11 D (range -0.50 to -5.00 D); +4.71 D (range +3.51 to +6.00 D) in 50 eyes (middle dioptric group), with a mean sphere of +5.58 D (range +4.00 to +7.00 D) and a mean cylinder of -1.83 D (range -0.50 to -4.50 D); and +7.26 D (range +6.01 to +10.00 D) in 24 eyes (high dioptric group), with a mean sphere of +8.25 D (range +6.50 to +10.00 D) and a mean cylinder of -1.98 D (range -0.50 to -4.00 D) in 24 eyes. Postoperative results were measured at 10 days and 6 months. RESULTS: At 6 months, the mean residual subjective spherical defect was +0.32 D (range -0.50 to +1.00 D) in the low dioptric group, with a mean cylinder of -0.61 D (range 0.00 to -1.75 D); all eyes were within +/- 1.00 D of emmetropia. The mean defect was +0.82 D (range 0.00 to +2.50 D) in the middle dioptric group, with a mean cylinder of -0.61 D (range 0.00 to -2.50 D); 80% of eyes were within +/- 1.00 D of emmetropia. The mean defect was +1.10 D (range -0.50 to +3.00 D) in the high dioptric group, with a mean cylinder of -1.39 D (range 0.00 to -3.25 D); 77% of eyes were within +/- 1.00 D of emmetropia. In the study group as a whole, 90% of eyes had a cylinder correction within +/- 1.00 D of emmetropia. Uncorrected visual acuity (UCVA) was 0.50 (20/40) or better in 23.4% of eyes preoperatively and 0.50 (20/40) or better in 71.0% 6 months postoperatively. CONCLUSIONS: Steepening the flatter meridian with the MultiScan System safely and effectively corrected hyperopic astigmatism. The rapid recovery of UCVA was due not only to correction of the ametropia, but also to the centering provided by the active tracking system.
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Bilateral cataract extraction with posterior chamber intraocular lens (IOL) implantation was performed in a patient after previous photorefractive keratectomy, radial keratotomy (RK) combined with astigmatic keratotomy, and retreatment of RK. Significant hyperopic error was observed after cataract surgery, and the IOLs were eventually exchanged in both eyes. A review of this case found that the refractive error was smaller when a refraction-derived keratometric value was selected for IOL power calculation. Nevertheless, hyperopic error still occurred.
We report a case of acute angle-closure glaucoma 1 year after hyperopic laser in situ keratomileusis (LASIK). The glaucoma was resolved with laser iridotomy, and a prophylactic iridotomy was performed in the fellow eye. Corneal topography was performed 2, 5, and 18 weeks after the acute episode. A myopic shift occurred after the episode and resolved within 3 months. Hyperopic patients with narrow angles are at risk for angle closure and should be carefully monitored.
PURPOSE: To evaluate the effect of laser thermokeratoplasty (LTK) in eyes that previously had a lamellar corneal cut. SETTING: University of Al-Azhar, Cairo, Egypt, and Instituto Oftalmológico de Alicante, Spain. METHODS: In 15 eyes (10 patients), noncontact LTK was applied 6 to 8 weeks after a lamellar corneal cut had been made. Central pachymetry, keratometry, and videokeratography were performed and uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest and cycloplegic refractions measured before and 1, 6, 12, and 18 months after LTK. RESULTS: Mean follow-up was 19.13 months. Mean refraction was +5.93 diopters (D) +/- 1.9 (SD) before LTK and -0.43 +/- 1.5 D at 1 month, +1.63 +/- 1.6 D at 6 months, 1.91 +/- 1.41 at 12 months, and +2.01 +/- 1.5 D at the end of the study. Total regression did not occur in any case. Mean BSCVA before LTK was 0.66 +/- 0.2, and spontaneous visual acuity at the end of the study was 0.58 +/- 0.18. No patient lost any lines of preoperative BSCVA. There was no significant difference between the results at 12 months and at the end of the study. CONCLUSION: Corneal lamellar cutting appeared to improve the magnitude of the refractive effect of noncontact LTK and to decrease the amount of regression.
INTRODUCTION: We wished to determine whether final visual acuity is dependent on age at optical correction or presence of esotropia in children with bilateral high hypermetropia. METHODS: We reviewed the charts of all patients at Childrens Hospital Los Angeles Division of Ophthalmology with bilateral hypermetropia of greater than or equal to 5D who were able to provide objective visual acuity outcomes with Snellen letters or linear E. RESULTS: One hundred thirteen patients met entry criteria. The age at first optical correction ranged from 8 months to 141 months (average 45 months). Initial visual acuity (before optical correction) was obtainable in 82 patients. Initial visual acuity ranged from 20/20 to 20/200, with 57% of patients having acuity better than or equal to 20/40. Final visual acuity (after optical correction) ranged from 20/20 to 20/70, with 109 patients (96%) having acuity better than or equal to 20/40 and 104 patients (92%) having acuity better than or equal to 20/30. There was no relationship between final visual acuity and age that spectacles were first worn. Ninety-five patients (84%) had esotropia with or without glasses, and six of these (6%) had final visual acuity less than 20/30. Of the 18 patients with orthotropia, three (16%) had final visual acuity less than 20/30. The prevalence of ametropic amblyopia in patients with esotropia and orthotropia was not significantly different (p = 0.18). CONCLUSION: Visual acuity outcome in children with high hypermetropia is generally good regardless of age at initial optical correction or presence of strabismus. A significantly increased risk for ametropic amblyopia was not found in those patients with orthotropia.
BACKGROUND AND OBJECTIVES: The chronic intestinal pseudo-obstruction due to visceral myopathy is a disorder resembling bowel obstruction but without mechanical occlusion. Frequently, parenteral nutrition becomes the final palliative treatment. A patient affected with this syndrome for 16 years was suffering causalgic pain provoked by intraveneous perfusion. Stellate ganglion block was requested in the hope of maintaining the perfusion. METHODS: Stellate ganglion block not only stopped the pain but unexpectedly, it temporarily relieved the pseudo-obstruction symptoms. Two radiofrequency coagulations in the stellate ganglion prolonged the beneficial effects on gastrointestinal transit for more than 3 weeks, after which the symptoms returned. Multidisciplinary and multicenter advice was that further destructive treatments not be attempted. RESULTS: Repetitive stellate ganglion blocks with 2 mL of bupivacaine 0.75% restored gastrointestinal function for more than 3 weeks. However, after performance of radiofrequency coagulation, infiltration with bupivacaine was followed by hypermetropia on the right eye of 2 weeks duration. CONCLUSIONS: The relationship between stellate ganglion block and gastrointestinal function has not been described. This case report does not provide sufficient information to recommend this technique for pseudo-obstruction symptoms. Moreover, the result in this case is a fortuitous observation, lacking a clear scientific explanation. Further study may be warranted.
The current state of research into experimentally induced refractive errors is reviewed. The area is analysed in three components-the transduction of defocus or deprivation, the vector for transmitting the error message from the retina to the outer tunics of the eye, and the identity of the effector for causing growth modulation in the sclera. Anatomical, pharmacological, electrophysiological and optical factors are considered in terms of which elements of the retina are necessary to support a refractive response to deprivation or defocus. Two of the current models are discussed-one emphasizing the role of the choroid in effecting ocular and refractive change, while the second model approaches the problem from the aspect of scleral changes that are associated with growth adaptation without emphasis on the error detection mechanism. A third model is proposed in which the error signal for deprivation or defocus is detected in the outer retina and where error is translated through separate signals for stimulus brightening and darkening into a net signal for fluid flow across and under the active control of the retinal pigment epithelium with the fluid communication between the vitreous chamber and the choroidal lymphatics. The directions of research both fundamental and clinical which are needed to create pharmaceutical or environmental solutions to refractive control are discussed.
Chickens were raised with either translucent occluders or lenses, both under normal light cycles (12-h light/12-h dark) and in constant light (CL). Under normal light cycles, eyes with occluders became very myopic, and eyes with lenses became either relatively hyperopic (positive lenses) or myopic (negative lenses). After the treatment, retinal dopamine (DA), DOPAC, and serotonin levels were measured by high-pressure liquid chromatography (HPLC-EC). A significant drop in daytime retinal DOPAC (-20%) was observed after 1 week of deprivation, and in both DOPAC (-40%) and DA (-30%) after 2 weeks of deprivation. No changes in retinal serotonin levels were found. Retinal DA or DOPAC content remained unchanged after 2 or 4 days of lens wearing even though the lenses had already exerted their maximal effect on axial eye growth. When the chickens were raised in CL, development of deprivation myopia was reduced (8 days CL) or entirely blocked (13 days CL). Lens-induced changes in eye growth were not different after either 6 or 11 days in CL, compared to animals raised in a normal light cycle. Thirteen days of CL resulted in a dramatic reduction of DA and DOPAC levels, but serotonin levels were also lowered. The results suggest that lens-induced changes in refraction may not be dependent on dopaminergic pathways whereas deprivation myopia requires normal diurnal DA rhythms to develop.
PURPOSE: Cross-sectional studies have consistently shown younger people to be less hyperopic than older people, but it is not known if this reflects a myopic shift from one generation to the next or a true age-related shift. METHODS: We used data from three population surveys to study cohort phenomena and true age-related changes in refraction of elderly people in southern Sweden. Differences concerning the use of cycloplegics made us restrict comparisons between refractions in separate studies to persons aged 65 to 74 years, in whom our measurements were considered unlikely to have been affected by accommodation. RESULTS: An apparent increase in mean spherical equivalent as rapid as 0.6 D in 10 years was observed in our latest (and largest) cross-sectional survey. The myopic shift, from one generation to the next, was limited to 0.25 D in 25 years. This discrepancy was explained by a true age-related hyperopic shift between 55 and 70, which was confirmed in a longitudinal study of over 1000 persons followed for more than 8 years. CONCLUSION: A true age-related hyperopic shift between 55 and 70 does indeed exist, and should not be disregarded by anyone who is prescribing spectacles or performing surgery for refractive errors. In the long run, however, a persisting secular trend towards myopia could prove even more important.
PURPOSE: The aim of this study was to investigate the changes in refractive error during a three-year period among university students exposed to high educational demands. METHODS: A three-year longitudinal cohort study was performed among 224 Norwegian engineering students (mean age 20.6 years, 117 females and 107 males) measuring their refraction at the beginning and the end of the period. The examinations included automated and clinical refraction in cycloplegia. A total of 192 students (100 females and 92 males) completed the study. RESULTS: In the student population under study the prevalence of myopia increased significantly from 48% to 65% (p<0.001, right eye) and the mean refractive error increased significantly from -0.64+/-2.18 D (n=224) to -1.21+/-2.30 D (n=192) (p<0.001, right eye) during the period. Of eyes emmetropic at the start of the study (n=49, right eye), 59% became myopic. Among the eyes initially myopic (n=92, right eye), 73% progressed further into myopia, with at least -0.37 D during the three-year period. Of eyes initially hyperopic (n=51, right eye), 8% became myopic, while 14% became emmetropic. CONCLUSIONS: A shift in refraction towards myopia is frequent among university students during their study period.
PURPOSE: To study refractive state and visual acuity in citizens of Reykjavik 50 years and older. METHODS: 1700 persons were randomly selected from the national population census. 1379 could be located and qualified whereof 1045 participated. Evaluation of refraction was performed using Nidek ARK 900 autorefracto-keratometer. Visual acuity was tested on a Snellen chart. RESULTS: The prevalence of hypermetropia increases with age by 0.3 D in five years. The prevalence of "against the rule" astigmatism increased on average 5.3% and oblique 3.9% in five years. Analysis of corneal astigmatism measured by keratometer shows an "against the rule" change with age. CONCLUSIONS: Hypermetropia increases by age. The prevalence of astigmatism increases and the axis turns to "against the rule". The changes in total astigmatism and corneal astigmatism is almost parallel which might indicate that the "against the rule" change is related to changes in the cornea.
PURPOSE: To study the effect of exercise on the configuration of the anterior chamber angle in healthy persons. METHODS: Both eyes of 22 healthy persons were scanned by Ultrasound Biomicroscopy. Before and after 10 minutes of exercise the anterior chamber angle and the area of the peripheral anterior chamber were measured on the scannings. RESULTS: After exercise the anterior chamber angle/peripheral area increases in all eyes due to changes in the iris configuration. The myopic group shows the largest change. CONCLUSION: Reverse pupillary block (iris concavity) is not pathognomonic in pigmentary glaucoma, it occurs in all normal eyes after exercise, most pronounced in myopics. Consequently, the difference between physiological and pathological reverse pupillary block has to be clarified.
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