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At least 181 records · Page 10Linked to original sources
PubMed1995

[Intrastromal thermokeratoplasty for correction of spherical hyperopia: a 1-year prospective study].

Thermokeratoplasty (TKP) is a new procedure for surgical correction of hyperopia. It uses controlled thermal burns of the peripheral cornea with a retractable cautery probe tip in a radial pattern up to a premarked optical central zone. The thermal effect shrinks the peripheral cornea and steepens the central cornea. In this report, we prospectively evaluated for one year, anatomical, functional and refractive results of a group of 18 eyes treated with TKP (14 patients). Mean preoperative spherical equivalent of +3.62 diopters (D) was +1.85 D at 12 months resulting in a mean refractive variation of -1.76 D. The refractive effect was significant at the first postoperative month, and subsequently regressed so that the average refractive correction was 55% at one year. We did not observe any severe anatomical or functional complications during the follow up period. Regression of the refractive effect after TKP seems to be related to the remodeling response of corneal stroma surrounding points of coagulation. Like other current techniques of surgical correction of hyperopia (hexagonal keratotomy, TKP using Holmium-YAG laser, Excimer laser), TKP is a procedure for which optical results at one year show poor predictability and stability. We suggest that adjustments to the surgical prediction software and long term studies would allow to improve our results.

Adult↗
PubMedDate not supplied

Arcuate keratotomy for the correction of spherical hyperopia in human cadaver eyes.

BACKGROUND: A new experimental surgical technique to correct spherical hyperopia by steepening of the central corneal curvature was performed on human cadaver eyes. METHODS: Ten eyes were used in the study. All were pretreated with glycerin to ensure a uniform corneal thickness between .55 and .65 mm on ultrasonic pachometry. A constant intraocular pressure of approximately 30 to 40 mm Hg was maintained in each eye by the injection of saline into the vitreous cavity. This was verified by pneumotonometry. A vertical blade diamond knife was set at 100% of the thinnest of four paracentral readings. Each eye underwent preoperative computed topography. One set of five eyes had 12 incisions made following a 5.75-millimeter diameter Mendez hexagonal marker that included unconnected T incisions at each junction (ie, "Hex T" pattern). The other set of five eyes had four arcuate incisions made following a 6-millimeter diameter zone marker; each incision was 60 degrees in arc. Immediately after surgery, computed topography was repeated. RESULTS: The hexagonal keratotomy set of eyes had an average steepening of the cornea of 0.80 D with a range of -1.05 to + 4.38 D. The arcuate keratotomy set had an average steepening of +2.12 D with a range of +1.27 to +3.27 D. CONCLUSIONS: This study suggests arcuate keratotomy may be a more effective procedure in the correction of spherical hyperopia when compared with hexagonal keratotomy. The amount of corneal steepening achieved in a cadaver eye model may not be the same as when performed in vivo.

Cornea↗
PubMedDate not supplied

Excimer laser photorefractive keratectomy for hyperopia.

BACKGROUND: Excimer laser photorefractive keratectomy has generated considerable interest as a technique for correcting myopia. In this study, the excimer laser was used to correct hyperopia. METHODS: A prospective clinical study based on the results of photorefractive keratectomy in 23 consecutive hyperopic eyes (one eye per patient) is presented. The excimer laser used in this study was a MEL 60 (Aesculap-Meditec); this laser emits 193-nanometer laser light. A 1-year follow-up study of two groups of eyes was performed. All patients were followed for 12 months. The first group comprised 15 hyperopic eyes with preoperative refraction between +2.0 and +7.5 diopters (mean spherical equivalent +4.7 +/- 1.6 D). The second group comprised eight aphakic eyes with preoperative refraction between +11.0 and +16.0 D (mean spherical equivalent +13.1 +/- 2.0 D). RESULTS: In group 1, 12 eyes (80%) were within +/- 1.0 D of the intended correction (baseline, +2.0 to +7.5 D) after 1 year. In group II, only three of the eight aphakic eyes (37%) were within +/- 1.0 D of the intended final refraction (baseline, +11.0 to +16.0 D). The stability of refraction in group I was better than in group II. At 12 months, best corrected visual acuity was unchanged in 14 eyes of group I. One eye had lost two lines. In group II, best corrected visual acuity was unchanged in six eyes after 12 months. In two eyes, best spectacle-corrected visual acuity was lower than the preoperative value, because of decentration of the ablation zone. After 1 year, 80% of the eyes in group I and 25% of those in group II had a visual acuity of 20/40 or better. CONCLUSION: Photorefractive keratectomy is an efficient and relatively safe procedure for correcting hyperopia up to +7.5 D. The predictability is good. Results of photorefractive keratectomy to correct highly hyperopic (aphakic) eyes are not as encouraging. Three patients in this study lost one to three lines of best spectacle-corrected visual acuity due to decentration of the clear zone. Two of the patients belonged to group II. Therefore, we do not recommend photorefractive keratectomy in highly hyperopic eyes, especially if they are aphakic, because even slight decentration may lead to loss of best corrected visual acuity. As in other refractive surgical procedures, great care must be taken to improve the centration of the clear zone.

Adult↗
PubMedDate not supplied

Holmium:YAG laser thermokeratoplasty for hyperopia and astigmatism: an overview.

The holmium:YAG laser can be used to perform corneal collagen shrinkage and treat refractive errors. Studies are underway for the treatment of hyperopia by shrinking collagen in the peripheral cornea, which produces central and paracentral steepening. There is initial overcorrection followed by a regression of effect postoperatively, which appears to stabilize 4 to 6 months postoperatively. Refinement of current nomograms and definition of the amount of expected regression will enhance its accuracy. The holmium:YAG laser may be superior to radial thermokeratoplasty with a hot needle. Nearly 100 years ago, Lans was the first to report that heating of the cornea could induce collagen shrinkage with resultant corneal curvature changes. Various collagen shrinkage procedures have evolved since then. To date, the most well-known form of collagen shrinkage involves the hot needle and a technique developed by Fyodorov to do radial thermokeratoplasty for hyperopia. This article will review the current state of holmium:YAG laser technology and the advantages it may provide over radial thermokeratoplasty.

Astigmatism↗
PubMed1996

Treatment of astigmatism associated with myopia or hyperopia with the holmium laser: second year follow-up.

BACKGROUND AND OBJECTIVE: In 1993, the Summit Technology apogee system for treating astigmatism was not available, so (to avoid the deep cuts of astigmatic keratotomy) the Summit Holmium: YAG laser was used to treat astigmatism associated with myopia; an excimer laser photorefractive keratectomy was to be performed when the keratometry readings had stabilized. The holmium:YAG laser also was utilized to concurrently treat hyperopia and astigmatism. PATIENTS AND METHODS: For myopic astigmatism, four holmium spots were administered, two on either side of the optical zone. An optical zone of 6.5 mm was used for keratometric astigmatism of 4.00 diopters (D) or greater; 7.0 mm for 3.00 to 3.90 D; 7.5 mm for 1.50 to 2.90 D. For hyperopic astigmatism, two extra spots were placed in the inner treatment ring, one on either side of the flattest meridian for 1.50 to 2.90 D of keratometric astigmatism. By omitting the outer ring treatments in the steeper meridian and using four extra spots, two on either side of the flattest meridian in the inner ring, 3.00 D or more was treated. RESULTS: Thirty-one myopic eyes were treated; five were lost to follow-up; 12 have subsequently had a photoastigmatic refractive keratectomy (PARK); six have had a PRK; eight had had no further procedures. Seven eyes now have 18 months of follow-up or more (and have not had a PARK); the four successes are presented in detail and it appears that their keratometry readings are nearly stable. CONCLUSION: Four of 7 (57%) myopic eyes, which had holmium laser treatment of associated astigmatism, can be considered as successes after 18 months or more follow-up. Keratometry readings are nearly stable; further follow-up is required to determine if regression continues. The treatment of astigmatism simultaneously with hyperopia treatment with the holmium laser was not successful.

Aluminum Silicates↗
PubMed1996

Holmium:YAG laser thermokeratoplasty to correct hyperopia: two years follow-up.

BACKGROUND AND OBJECTIVE: Treatment of hyperopia is more of a challenge than PRK but the development of the holmium:YAG laser has provided a more controlled way of carrying out laser thermokeratoplasty (LTK). PATIENTS AND METHODS: Twenty two eyes with hyperopia were treated with a Summit Technology OmniMed holmium laser by placing two rings of eight laser spots at 6.5 and 9 mm (centred on the visual axis) to produce a 4.00 diopters (D) correction. RESULTS: An average +2.10 D refractive correction was achieved in the 17 eyes with no induced astigmatism with an accuracy of 25% within 1.00 D, 60% within 2.00 D and 100% within 3.00 D. However, significant astigmatism (+1.25 to +2.5 Dcyl) was produced in 23% of eyes from 6 months post-laser and these required astigmatic LTK correction. CONCLUSIONS: The overall results were disappointing in that there was an approximate 50% regression at two years post-LTK. However, the rate of regression was very slow at 24 months, and most patients remarked how well they could see in the first few months following the treatment.

Adult↗
PubMed1997

The relationship between moderate hyperopia and academic achievement: how much plus is enough?

BACKGROUND: There is evidence linking uncorrected hyperopia in children with academic learning problems. METHODS: This study was designed to test that hypothesis and--given supportive data--to then address a second topic: the minimal amount of uncorrected hyperopia that appears to impede elementary school performance. RESULTS: The refractive status and achievement test scores of 782 first-through-fifth grade children were compared. CONCLUSIONS: Statistical analysis indicated significantly lower achievement test scores among hyperopic children whose refractive errors exceeded 1.25 D (ANOVA F = 12.51; df = 4; p = 0.014).

Child↗
PubMed1983

Hereditary posterior microphthalmos with papillomacular fold and high hyperopia.

Five patients had a bilateral hereditary ocular syndrome composed of posterior microphthalmos with a papillomacular fold and high hyperopia. Anterior segment dimensions were near normal; the vitreous compartment was markedly fore-shortened. A papillomacular retinal fold extending from the center of the fovea toward the optic nerve head was present. Visual acuity ranged from 0.05 (20/400) to 0.6 (20/33); refractive errors ranged from + 11.25 to + 17.50 diopters. An autosomal recessive pattern of inheritance is postulated.

Adult↗
PubMed1975

Bilateral microphthalmos without microcornea associated with unusual papillomacular retinal folds and high hyperopia.

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.

Adult↗
PubMed1995

Does experimentally-induced amblyopia cause hyperopia in monkeys?

We assessed refractive errors in 19 monkeys (Macaca nemestrina) raised with experimentally produced strabismus or unilateral defocus. These procedures resulted in hyperopic anisometropia in 10 monkeys. All 10 of the hyperopic animals were amblyopic; the amblyopic eye was always the more hyperopic eye. The degree of anisometropia was correlated with the degree of amblyopia. Hyperopic anisometropia did not develop in non-amblyopic animals. There was an association between early onset of visual abnormality and later development of hyperopic anisometropia. Since the refractive changes were correlated with changes in axial length and vitreous chamber depth, we suggest that amblyopia may cause alterations in eye growth and late-onset hyperopia.

Amblyopia↗
PubMed2004

Laser in situ keratomileusis for high hyperopia in awake, autofixating pediatric and adolescent patients with fully or partially accommodative esotropia.

PURPOSE: To establish the safety and efficacy of laser in situ keratomileusis (LASIK) in pediatric and adolescent patients with bilateral visual acuity of 20/30 or better and accommodative or partially accommodative esotropia. SETTING: Department of Ophthalmology and Visual Science, University of Texas-Houston Medical School, Houston, Texas, USA. METHODS: The study comprised 30 eyes of 15 consecutive patients with accommodative or partially accommodative esotropia who met eligibility requirements and had bilateral LASIK using the Alcon Summit Autonomous LADARVision excimer laser to correct a refractive error after January 2001. All patients were awake and autofixating during the procedure. RESULTS: The mean age of the patients was 13.9 years (range 9.1 to 18.8 years) and the mean refractive error, +5.35 diopters (D) (range +3.75 to +8.50 D) with anisometropia of 2.0 D or less. The mean follow-up was 15.7 months (range 9.5 to 22.5 months). No intraoperative complications were encountered. The percentage of undercorrection [100% -[(treatment achieved/treatment attempted) x 100%]] [mean 34% +/- 17% (SD), coefficient of variation (SD/mean) 0.50, range 5% to 58%] was higher than expected. Seven patients (47%) required enhancement due to undercorrection of hyperopia with diplopia (6 patients) or astigmatism with decreased visual acuity (1 patient). In this small series, no patient lost best corrected visual acuity or stereo acuity. CONCLUSION: Laser in situ keratomileusis can safely and effectively reduce refractive error in this group of patients; however, patient selection is extremely critical and enhancement was required in almost half the patients.

Accommodation, Ocular↗
PubMed2006

Scheimpflug measurement of intraocular lens position after piggyback implantation of foldable intraocular lenses in eyes with high hyperopia.

PURPOSE: To investigate the position of 3-piece foldable intraocular lenses (IOLs) after piggyback implantation for high hyperopia. SETTING: University Eye Hospital, Johann Wolfgang Goethe University, Frankfurt am Main, Germany. METHODS: Eight eyes of 5 highly hyperopic patients had phacoemulsification and implantation of 2 foldable IOLs. In 3 eyes, both IOLs were implanted in the capsular bag. In 5 eyes, 1 IOL was placed in the capsular bag and the second IOL in the ciliary sulcus. Intraocular lens optic tilt and decentration, combined thickness of both IOLs, and anterior chamber depth (ACD) were measured postoperatively over a period of 18 months using Scheimpflug photography. RESULTS: All eyes with both IOLs in the capsular bag showed interpseudophakic opacification, with a mean increase in combined IOL thickness of 0.4 mm, a decrease in ACD of 0.3 mm, and a corresponding hyperopic shift of 4.00 diopters. Eyes in which the anterior IOL was placed in the ciliary sulcus showed no changes in refraction or combined IOL thickness. In these eyes, the anterior IOL had a higher mean decentration (0.49 mm +/- 0.20 [SD] after 12 months) than the posterior IOL (0.21 +/- 0.13 mm after 12 months). CONCLUSIONS: Piggyback IOL implantation with placement of 2 foldable IOLs in the capsular bag can be followed by a hyperopic shift that may be caused in part by displacement of the IOLs. Placement of the anterior IOL in the ciliary sulcus can lead to higher decentration of this IOL.

Adult↗
PubMedDate not supplied

Surgical correction of hyperopia.

Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.

Corneal Surgery, Laser↗
PubMed1993

Hyperopia as a risk factor for nonarteritic anterior ischemic optic neuropathy.

The most convincing morphologic component in the pathogenesis of nonarteritic anterior ischemic optic neuropathy is the anatomically small and crowded optic nerve head. Because the appearance of the optic disk is presumed to be related to underlying refractive error, we sought to determine if a particular refractive error places patients at additional risk for, or affords protection from, nonarteritic anterior ischemic optic neuropathy. We compared refractive errors of 50 patients with nonarteritic anterior ischemic optic neuropathy to an age-matched and eye-matched control population. The mean refractive error (in spherical equivalents) for the nonarteritic anterior ischemic optic neuropathy group was +0.26 diopter (SD +/- 2.08); the mean refractive error for controls was -0.86 diopter (SD +/- 2.91) (P = .027). Our results suggest that patients who have nonarteritic anterior ischemic optic neuropathy are less myopic than a control population. Whether it is myopia that protects from, or hyperopia that predisposes to nonarteritic anterior optic neuropathy, our results imply another anatomically based factor that characterizes eyes that develop nonarteritic anterior ischemic optic neuropathy. Those eyes tend to be minimally hyperopic.

Arteritis↗
PubMed1980

Acquired hyperopia with choroidal folds.

Six healthy adults suddenly developed a unilateral or bilateral hyperopic shift in refractive error of up to 6 diopters. Fundi of affected eyes showed typical choroidal folds. Visual acuity was improved to normal or near normal by plus lenses, and refraction and fundus appearance have remained stable for up to 23 years. The benign syndrome of acquired hyperopia with choroidal folds deserves emphasis in order to spare patients from unnecessary and potentially hazardous neurosurgical or orbital investigation.

Adolescent↗
PubMed1993

Hyperopia and neovascularization in age-related macular degeneration.

PURPOSE: Refractive errors for phakic eyes of patients referred with age-related macular degeneration were reviewed to determine whether some range of refractive error might be a risk factor for the neovascular form. METHODS: The authors compared refractive errors of 198 patients with unilateral neovascular disease with refractive errors of 129 patients with bilateral dry disease. These groups had comparable distributions with respect to age, sex, and visual acuity of their better eyes. Student's t tests and multiple linear regression analyses were performed to assess group differences in mean refractive error. Contingency table and multiple logistic regression analyses were performed to determine odds ratios for having the neovascular form based on a stratification of refractive error. RESULTS: By comparing better eyes of the two groups, patients with the unilateral neovascular form had an average spherical equivalent that was 1.0 diopter (D) more hyperopic than that of patients with the bilateral dry form (P < 0.001). Patients with a refractive error of +0.75 D or greater were more likely to have the neovascular form compared with patients with other refractive errors (odds ratio, 2.40; 95% confidence interval, 1.53-3.78; P < 0.001). Similar relationships between the two groups of patients were found by comparing worse eyes. CONCLUSION: These findings suggest that hyperopia is a risk factor for choroidal neovascularization among patients referred with age-related macular degeneration.

Aged↗
PubMed1999

Acute corneal necrosis after excimer laser keratectomy for hyperopia.

OBJECTIVE: To describe a new, rare clinical complication after routine excimer laser photorefractive keratectomy to correct hyperopia. DESIGN: Case report with clinicopathologic correlation. MAIN OUTCOME MEASURES: Four weeks after treatment with excimer laser, a perforating keratoplasty was performed for persistent corneal opacities. The corneal button was examined using light and electron microscopy. Special immunohistochemical stains were used to detect apoptosis. RESULTS: The patient developed corneal opacities, endothelial precipitates, and a fibrinous exudate in the anterior chamber after the laser treatment. The changes did not respond to therapy directed against bacteria, fungi, and Acanthamoeba. All examinations and special stains were negative for micro-organisms. By light microscopy, an anterior zone of corneal necrosis was present with a moderate amount of acute inflammatory cells. At the interface between necrotic and viable corneal stroma, keratocytes with typical features of apoptosis were detected by immunohistochemistry and electron microscopy. CONCLUSION: This is the first full histopathologic report of a case of acute corneal necrosis with signs of apoptosis after excimer laser therapy of the cornea. Surgeons should be aware of this rare but potentially severe complication.

Acute Disease↗
PubMed2006

[Bilateral posterior microphthalmos associated with papillomacular fold and severe hyperopia].

Posterior microphthalmos with papillomacular fold is a rare disorder that involves both eyes without other ocular or systemic abnormalities. It is characterized by a short posterior segment with a normal anterior segment. We report the case of a 3.5-year-old boy with high hyperopia. The fundus examination showed bilateral papillomacular fold and ultrasonography confirmed the posterior microphthalmos. We comment on clinical characteristics, pathogenicity, and inheritance modes of this rare congenital disorder.

Abnormalities, Multiple↗