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Hyperopia of 1.00, 1.50, and 2.00 D was induced in 42 subjects by means of concave lenses. A significant decrease in performance on a standard intelligence test occurred with the highest-power lenses. Symptoms induced indicate that the results are applicable to hyperopia. Prescriptions and vision screening criteria for hyperopia are indicated.
BACKGROUND: Hyperopia is a possible complication following radial keratotomy. In this article, we describe a circular and interrupted corneal compression suture technique for the correction of hyperopia induced by radial keratotomy. METHODS: A retrospective study was performed to evaluate the effectiveness of this procedure in nine consecutive patients. RESULTS: The procedure achieved an average of -1.70 diopters change in spherical equivalent refraction. This accounted for an overall correction of 68% of the hyperopia caused by radial keratotomy after a minimum 3-month follow up. Seven of nine eyes (78%) were within 1.00 D of emmetropia after surgery. Uncorrected visual acuity of 20/40 or better was present in only two eyes (22%) preoperatively, and nine eyes (100%), after the corneal suturing procedure. The mean improvement of uncorrected visual acuity was 4.0 Snellen lines (P = .0004). All patients were pleased with their visual outcomes. CONCLUSIONS: We found that this technique is an easy, safe, and reasonably successful treatment for radial keratotomy overcorrection.
Twenty-three cynomolgus monkeys underwent 360-degree disinsertion and retrodisplacement of the ciliary muscle in one eye. Ten to 12 weeks after unilateral disinsertion, resting refraction in the "disinserted" eyes was more hyperopic than in the opposite eyes by 1.12 +/- 0.21 (mean +/- S.E.M.) diopters (p less than 0.001). Accomodative responses to intramuscular pilocarpine (2 or 3 mg/kg) were 0.90 +/- 0.14 (mean +/- S.E.M.) diopters in the disinserted eyes and 13.88 +/- 0.79 diopters in the opposite eyes. The induced hyperopia and loss of accommodation in the disinserted eyes seemed permanent, persisting for at least 14 months in one monkey and 29 months in three monkeys tested periodically after disinsertion. By light microscopy, the ciliary muscle in the disinserted eyes appeared normal and was contracted by pilocarpine. Scanning electron microscopy of the accommodative apparatus revealed retrodisplacement of the ciliary muscle, ciliary processes, and zonular plexus in the disinserted eyes. Structural alterations in the zonular apparatus seemed insufficient to account for the physiological findings. Hyperopia and loss of accommodation following ciliary muscle retrodisplacement are consistent with a new theory of zonular action during accommodation.
BACKGROUND: No effective treatment for hyperopia following radial keratotomy has been described. A new surgical technique of two purse-string intrastromal sutures was investigated for correction of this hyperopia. METHODS: Eighteen radial keratotomy patients who were unhappy with uncorrected vision and who were unsatisfied with contact lens or spectacle correction, after informed consent, underwent corneal suturing. The 19 hyperopic eyes included 5 original overcorrections, 5 overcorrections after reoperation, and 9 progressive hyperopes. The refractive error ranged from +1.25 to +5.75 diopters spherical equivalent (mean +3.47 D). Presuturing uncorrected visual acuity ranged from 20/50 to 20/400 with 11 eyes (58%) 20/100 or worse. RESULTS: The follow up after double purse-string suturing averaged 24 months (range, 12 to 47 months). All patients had follow up of at least 1 year; 14 patients (74%) had follow up of 2 years or more. The change in refractive spherical equivalent following surgery averaged -3.30 D (range, -1.00 to -7.50 D). The steepening in average keratometry was 4.10 D (range, 1.00 to 8.00 D). The refraction after suturing averaged -1.12 D (range, +2.50 to -3.50 D). Uncorrected visual acuity after suturing was 20/40 or better in 14 eyes (74%), and 20/50 to 20/80 in 5 eyes (36%). There were no significant intraoperative, early or late postoperative complications. Seventeen eyes were either the same or gained 1 line of acuity; 2 eyes gained 2 lines of acuity; no eyes lost any lines of refractive Snellen acuity. CONCLUSIONS: The placement of two purse-string intrastromal sutures appears to provide significant steepening of the central cornea following excessive flattening after radial keratotomy. The steepening effect appears to remain stable with greater than 1-year follow up. This surgical technique offers an alternative to symptomatic hyperopic postradial keratotomy patients who cannot be corrected with spectacles or contact lenses.
A 23-year-old man had bilateral microphthalmos without microcornea. The eyes measured about 15 mm in length by ultrasound while the corneas were 11 mm in diameter. A distinctive, elevated, funnel-shaped retinal fold stretching between the disk and the macula was present bilaterally. Other unusual aspects were the deep anterior chambers and uncompromised chamber angles. This combination of anomalies is believed to be the result of a failure of growth of the posterior outer coats of the eye. These were of insufficient size to accommodate the excess sensory retina which folded to conform to its outer structural shell. Other cases of high hyperopia may in some instances be cases of microphthalmos, unrecognized because of normal-sized corneas.
We report a case of evolutive high hyperopia in a child aged 10 years. It is associated with organic amblyopia due to a large papillomacular retinal fold. Ultrasonography and CT scan helped to establish the diagnosis. This is probably a hereditary disease affecting the development of the posterior sclera.
BACKGROUND: A new experimental surgical technique to correct hyperopia by steepening the central corneal curvature was performed on the eyes of rabbits. METHODS: After X-shaped incisions at four quadrants of the paracentral cornea, four deep, transverse interrupted sutures were placed across the incisions and the knots were tightened to compress the corneal tissue in the direction of the suture. Twenty-three eyes of 12 albino rabbits were divided into group A (7 eyes) with a 4-millimeter diameter clear zone, group B (9 eyes) with a 6-millimeter diameter clear zone, and control group C, consisting of 7 contralateral eyes of group A without any incision or suture. RESULTS: There was significant (p < .01) steepening of the central cornea as measured by the keratometer at postoperative 8 weeks in group A (+1.88 diopters) and group B (+1.68 D) compared with that of the control group C (-3.44 D). The difference in effect of hyperopic correction between groups of A and B was not statistically significant. CONCLUSIONS: This procedure serves only as an experimental model of corneal response to incisions and sutures and is not for use in human corneas.
We present a patient who underwent bilateral radial keratotomy (RK) followed by a bilateral revisional RK for undercorrection. After the second procedure, the patient had a severely flattened left cornea, with marked hyperopia and irregular astigmatism. The right eye, however, remained myopic, causing extreme anisometropia. We hypothesize that the different results in these two eyes may have been due to a critical number of damaged left corneal stromal fibers. Patients undergoing revisional RK or requiring additional incisions may be at increased risk for such a complication.
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Two infants developed accommodative esotropia during their first six months of life. One infant, whose age at onset was 4 1/2 months, had 4.50 diopters of hyperopia. The second infant, whose age at onset was 5 months, had 3.50 diopters of hyperopia. In both infants, the eyes completely aligned with hyperopic correction. Two points are stressed. First, when the amount of hyperopia exceeds +3.00, consideration should be given to an accommodative element as the cause of the esotropia, even if the child is only 4 to 6 months old. Second, even with small angles of esotropia, an accommodative element should be considered, if there is a substantial amount of hyperopia.
We have developed a lightweight plastic goggle with rigid contact lens inserts that can be applied to the eyes of newly hatched chicks to explore the range and accuracy of the developmental mechanism that responds to retinal defocus. Convex and concave lenses of 5, 10, 15, 20 and +30 D were applied to one eye on the day of hatching. The chick eye responds accurately to defocus between -10 and +15 D, although hyperopia develops more rapidly than myopia. Beyond this range there is first a levelling off of the response and then a decrease. The resulting refractive errors are caused mainly by increases and decreases in axial length, although high levels of hyperopia are associated with corneal flattening. If +/- 10 D defocusing lenses are applied nine days after hatching the resulting myopia and hyperopia are equal to about 80% of the inducing power. After one week of inducing myopia and hyperopia with +/- 10 D lenses, the inducing lenses were reversed. In this case, the refractive error did not reach the power of the second lens after another week of wear. Instead, astigmatism in varying amounts (0-12 D) was produced, being greater when reversal was from plus to minus. Finally, astigmatism can also be produced by applying 9 D toric inducing lenses on the day of hatching. The astigmatism produced varies from 2 to 6 D, and the most myopic meridian coincides with the power meridian of the inducing lens. This astigmatism appears to be primarily due to corneal toricity.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty two strabismus and 106 straight eyed patients with anatomically normal eyes were first photographed with a conventional camera equipped with a weak 100 mm teleobjective and coaxial flashlight and then examined clinically. The possibility of detecting strabismus, anisometropias and ametropias in the photographs by noting the localisation of the corneal reflexes and examining the appearance and lightness of the fundus reflexes and their possible asymmetry were tested in a double blind study. Even small angled strabismus cases could be found because of the asymmetrical localisation of the corneal reflexes. In 18 of the 22 strabismus cases (82%) there was asymmetrical lightness of the fundus reflexes and the fundus reflex of the deviating eye was lighter than that of the fixating eye. All the straight eyed anisometropias of 3.0 diopters or more (five cases) were observed in the photographs because of the asymmetrical appearance of the fundus reflexes. In straight eyed anisometropias of under 3.0 diopters, the fundus reflexes were symmetrical in 90 cases and asymmetrical in 11 cases (11%). Only three out of eight hyperopias of fomr +4.5 to +6.0 diopters were found because of the light crescent in the low part of the pupil. All myopias of over -4.0 diopters (14 cases) were observed because of the light crescent appearance in the upper part of the pupil. No pupillary crescents appeared with refractions of less than -1.75 diopters myopia or less than +4.5 diopters hyperopia; 172 eyes came within this range. Even a technician can perform, without premedication, the method tested here for rapid and simple screening to detect strabismus and straight eyed anisometropias of 3.0 diopters or more in small children or other patients who do not co-operate well in normal clinical examination. Over -4.0 diopters myopias can also be found. The method was rather unreliable for finding hyperopias, presumably because no cycloplegic drops were used.
A 5-1/2 year old black female initially presenting with a moderate angle esotropia and latent hyperopia developed a large angle constant exotropia 2 years after final correction of her refractive error. The occurrence of consecutive exotropia as a result of optical correction of hyperopia has been documented infrequently in the ophthalmologic literature and has rarely been mentioned in the optometric literature. While the overall risk for occurrence of this complication from correction of hyperopia may be small, it is a problem which may occur and can be avoided. Unfortunately, there is only limited information about the various risk factors that should be monitored to avoid the occurrence of an optically induced consecutive exotropia. What is available with regard to evaluation and management is scant, and there are no case reports emphasizing optometric management which includes the use of lenses, occlusion and vision therapy. The purpose of this paper is to present a case report of optically induced consecutive exotropia followed by a summary of the available information from the optometric and ophthalmologic literature. This combined information will aid optometrists managing these patients to avoid the occurrence of this problem and better understand the various management aspects when it does occur.
The refractive status of 3,099 children was analyzed. The result showed that the incidence and degree of hyperopia decreased gradually and those of myopia increased along with the growing up of children in ametropia. In binocular refractive amblyopia, high and medium hyperopia and myopia in severe and medium amblyopia were significantly more than those in mild amblyopia. In monocular refractive amblyopia, high and medium hyperopia and high myopia in the amblyopic eyes were more than those in the nonamblyopic eyes. The refractive status of binocular esotropic amblyopia had no significant difference in various ages and degrees of amblyopia. There was also no significant difference between the refractive status of the amblyopic and nonamblyopic eyes in monocular esotropic amblyopia. It was considered that refractive amblyopia was closely related to high ametropia and the deviation of the eye might be the main cause of strabismic amblyopia.
The effect of chronic changes in serum glucose concentration on refraction was studied by increasing the dose of insulin or chlorpropamide in 10 diabetic patients who initially had relatively high glucose concentrations. In every case when serum glucose concentration was reduced the vision became less myopic or more hyperopic. To assess acute changes. 10 diabetics (including four with aphakic eyes) were given an intravenous injection of glucose. In patients with intact lenses the vision became more myopic or less hyperopic following the administration of glucose, but in the aphakic eyes hyperopia increased. It is concluded from both the acute and chronic studies that higher levels of serum glucose concentration produce myopia and lower levels produce hyperopia. Furthermore, these changes are related to changes in the optical properties of the crystallin lens.
We conducted a nation-wide survey of the Prevalences of Myopia and other refractive errors in Israel, from data of medical examinations of an unselected population of 312,149 subjects ages 17 to 19 years. 80.47% of the population were emmetropic in both eyes. Myopia in both eyes was found in 16.27% of the population. The prevalence of monocular myopia was 1.69%. Manifest hyperopia in both eyes was found in 0.93% and astigmatism at least in one eye was found in 7.13%. The various errors of refraction (myopia, hyperopia and astigmatism) were more common among females.
The appearance of the retinal nerve fiber layer was studied in one eye of 203 normal Asians (59 with high myopia greater than or equal to -5 D, and 144 with emmetropia or hyperopia). "Cleavage" of the retinal nerve fiber layer was observed in 3 of these 59 highly myopic eyes, but there was no significant damage to either the retinal pigment epithelium or the choroid. In contrast, no cleavage was observed in the other 144 emmetropic or hyperopic eyes. High myopia (P = 0.0237, Fisher's exact test) was a significant risk factor for "cleavage" development in the retinal nerve fiber layer. The occurrence of a defect (nerve fiber loss) in the retinal nerve fiber layer in severe myopia (5/59, 8%) was also greater than that in either emmetropia or hyperopia (2/144, 1%; P = 0.0229). These results indicate that subtle changes can occur in the appearance of the retinal nerve fiber layer of the eye in some patients with asymptomatic myopia.