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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.
Myopia and hyperopia have been produced in chicks by applying specially designed convex and concave soft contact lenses to the eyes of newly hatched birds. After 2 weeks of wear, the eyes develop refractive states equivalent in sign and amount (+8 and -10 D) to the lens used. However, the lenses produce an artificial hyperopic shift during the first week of wear due to corneal flattening. We have developed a new approach involving the use of goggles with hard convex and concave contact lens inserts placed between the frontal and lateral visual fields. Myopia and hyperopia (+10 and -10 D) can be produced within days (4 days for hyperopia and 7 days for myopia) if the defocus is applied from the day of hatching. We can also produce significant amounts of astigmatism (1 to 5 D) axis at 90 degrees and 180 degrees by using cylindrical contact lens inserts. Although these last results are preliminary, they suggest that accommodation is not likely involved at this stage of refractive development because we do not believe that the accommodative mechanism can cope with cylindrical defocus. All spherical refractive errors produced using the goggle system appear to result from alterations in vitreous chamber depth.
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.
We studied a four-generation family with early-onset autosomal dominant retinitis pigmentosa, severe hyperopia, and axial eye lengths of less than 20 mm. The affected members had decreased vision, night blindness, typical peripheral retinal pigmentary changes, and electroretinographic abnormalities characteristic of retinitis pigmentosa. This pedigree suggests there is another variant of retinitis pigmentosa associated with hyperopia besides Leber's congenital amaurosis and preserved para-arteriole retinal pigment epithelium.
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.
Hyperopic thermokeratoplasty involves making controlled thermal burns in the corneal stroma in a radial pattern up to a premarked clear zone. It steepens the central cornea and reduces the hyperopia. A series of 117 radial thermokeratoplasty eyes done in the Soviet Union were analyzed. Mean preoperative hyperopia of +5.27 diopters (range = +0.50 to +17.00 D) was reduced at 12 months after surgery by a mean of -3.48 D, resulting in a mean postoperative spherical equivalent of +1.84 D. Average correction was 70.8%. Forty percent of eyes were corrected to less than 1.00 D residual refractive error; however, 58% were undercorrected by 1.00 D or more. The proportion of eyes seeing 20/40 or better unaided increased from 10% preoperatively to 52% by 3 months after surgery and remained at 53% at 12 months after surgery. Overall refractive stability was demonstrated during the 1st postoperative year. Stepwise regression showed that none of the preoperative or surgical factors significantly predicted outcome when all eyes were evaluated.
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.
Epikeratophakia for the correction of aphakia, myopia, hyperopia and keratoconus has overcome many of the objections to earlier lamellar refractive procedures (keratophakia and keratomileusis), such as the lamellar dissection of the recipients' healthy cornea over the visual axis and the need for expensive surgical equipment. It is reasonably reversible and repeatable. The complications observed in a series of 119 operations performed at the 2nd Department of Ophthalmology, University of Vienna, are discussed and compared with those reported in the literature. Serious complications, both intraoperatively and in the early and late postoperative period, that permanently threaten the patients vision are rare. Predictability and loss of effect in a significant percentage of myopic cases, caused by lack of precision during manufacturing of the lenticules and individual wound healing, makes careful patient selection mandatory.
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We present a new technique of hyperopic correction similar to radial thermokeratoplasty. A pulsed Ho: YAG laser was used that emitted radiation at 2.06 microns and was guided by a quartz fiber and a focusing hand piece. The penetration depth of this light in the cornea is about 400 microns. Eight or 16 concentric point coagulations result in steepening in the central cornea. This refractive change is inverse related to the distance to the cornea center, and it increases linearly with increasing laser pulse energy. In four blind eyes it was demonstrated that the parameters evaluated in cadaver eyes can be transferred to living eyes. Surprisingly, the refractive change so created of up to 5 dpt is stable within a period of 4 months. Immediately after surgery, concentric descemet folds can be detected, which gradually decrease within the period reported.
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