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PubMed2002

Conductive keratoplasty for the correction of low to moderate hyperopia: U.S. clinical trial 1-year results on 355 eyes.

OBJECTIVE: To document the 1-year safety, efficacy, and stability results of 355 eyes treated in the multicenter study of conductive keratoplasty (CK) used to correct low to moderate hyperopia. DESIGN: Nonrandomized comparative (self-controlled) trial. PARTICIPANTS: Twenty surgeons at 13 centers performed CK on the eyes of all patients enrolled in a multicenter, 2-year, U.S. phase III clinical trial. Treated eyes had +0.75 to +3.00 diopters (D) of hyperopia and < or =0.75 D of cylinder. Patients were 40 years of age or older. INTERVENTION: Low-energy, high-frequency current was applied directly into the peripheral corneal stroma through a delivery tip inserted at 8 to 32 treatment spots. The number of treatment spots was increased for increasing levels of hyperopia, but the amount of radiofrequency energy remained constant. Emmetropia was intended. All eyes were treated once (there were no retreatments). MAIN OUTCOME MEASURES: Data from 355 eyes with 1 year of follow-up were analyzed for safety and stability, and data from 318 eyes were analyzed for efficacy and predictability, as well as stability and safety. All patients reported on satisfaction and quality of vision after surgery. RESULTS: At 1 year, uncorrected visual acuity was < or =20/20 in 56%, < or =20/25 in 75%, and < or =20/40 in 92% of eyes. The manifest refractive spherical equivalent refraction was within 0.50 D in 63%, within +/-1.00 D in 89%, and within +/-2.00 D in 99%. Seven of 355 eyes lost 2 lines of best spectacle-corrected visual acuity at 1 year, but no eye lost >2 lines. One eye of 355 had induced cylinder of >2.00 D. The cycloplegic refractive spherical equivalent changed a mean of 0.25 +/- 0.50 D between months 3 and 6, 0.11 +/- 0.41 D between months 6 and 9, and 0.11 +/- 0.35 D between months 9 and 12. Refractive stability seemed to be attained by 6 months and remained stable through 12 months. Histology and confocal microscopy showed deep penetration of the treatment into the stroma. Endothelial cell counts were not changed by the treatment. CONCLUSIONS: CK seems to be safe, effective, and stable for correcting low to moderate spherical hyperopia in patients 40 years old or older. Treatment penetration is deep and cylindrical in shape, and it does not damage the corneal endothelium. Uncorrected visual acuity, predictability, and stability are as good as or better than those obtained with other techniques used to correct hyperopia.

Adult↗
PubMed2003

Treatment of simple hyperopia: comparison of laser in situ keratomileusis and laser thermal keratoplasty.

PURPOSE: To evaluate and compare the efficacy, stability, and safety of laser in situ keratomileusis (LASIK) and laser thermal keratoplasty (LTK) for the treatment of simple hyperopia. SETTING: John Hill Eye and Laser Centre, Cape Town, South Africa. METHODS: This retrospective study comprised consecutive patients having primary treatment of simple hyperopia of up to 3.0 diopters (D) with astigmatism of 0.5 D or less. Treatment methods were as follows: Group 1 (81 eyes), LASIK with the Nidek EC-5000 excimer laser; Group 2 (69 eyes), LASIK with the LaserSight LSX excimer laser; and Group 3 (84 eyes), LTK with the Sunrise holmium:YAG laser. RESULTS: The hyperopia decreased in all 3 groups. Both LASIK groups were stable by 1 month; there was continued regression in the LTK group for up to 18 months. The percentage of eyes achieving uncorrected visual acuities of 20/20 and 20/40 at 3 months were Nidek, 41% and 92%, respectively; LaserSight, 50% and 90%, respectively; and LTK, 21% and 89%, respectively. No eye lost more than 2 lines of best spectacle-corrected visual acuity. Surgically induced astigmatism (SIA) was evident in all 3 groups; it was highest in the LTK group. The mean posttreatment astigmatism was -0.47 D +/- 0.40 (SD) (range 0 to -1.50 D) in the Nidek group, -0.45 +/- 0.40 D (range 0 to -1.25 D) in the LaserSight group, and -0.81 +/- 0.51 D (range 0 to -2.25 D) in the LTK group. The enhancement rates were 16.75%, 22.57%, and 38.30%, respectively. Because of the SIA, 61% of the LTK enhancements were corrected with LASIK. CONCLUSIONS: All 3 treatment methods corrected hyperopia, but stability was achieved early in both LASIK groups, allowing early enhancement when necessary. Because LTK cannot currently correct astigmatism, many of the LTK repeat treatments required LASIK procedures. For these reasons, LASIK remains my preferred method to treat simple hyperopia up to +3.0 D.

Adult↗
PubMed1998

Laser in situ keratomileusis for hyperopia.

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) to treat hyperopia. SETTING: Instituto de la Vision, Buenos Aires, Argentina. METHODS: This nonrandomized study comprised 679 eyes of 321 patients having LASIK. Patients were divided into three groups based on preoperative spherical equivalent: Group A (low hyperopia, 2.00 diopters [D] or less); Group B (moderate hyperopia, between 2.00 and 3.00 D); Group C (high hyperopia, more than 3.00 D). The following were measured postoperatively: uncorrected visual acuity (UCVA); best spectacle-corrected visual acuity (BSCVA); refraction (evolution and distribution); lines of visual acuity gained and lost. Follow-up was 1 month in 79.4% of cases, 3 months in 75.5%, 6 months in 68.5% and 1 year in 38.3%. RESULTS: Six months after LASIK. 100% of cases in Group A, 95.3% in Group B, and 71.4% in Group C were within +/- 1.00 D of emmetropia; UCVA was 20/40 or better in 94.1, 100, and 87.8%, respectively. The percentage losing or gaining 0 +/- 1 line of BSCVA was 100, 97.6, and 100, respectively. CONCLUSIONS: Laser in situ keratomileusis was predictable and safe in the treatment of low and moderate hyperopia.

Adult↗
PubMed1990

Study of gene-environment effects on development of hyperopia: a study of 191 adult twin pairs from the Finnish Twin Cohort Study.

The Finnish Twin Cohort material was used to estimate genetic and environmental effects in the etiology of hyperopia (farsightedness). All twin pairs in the cohort born before year 1927 (age 60 years and over at the time of the study), with both members alive, were sent a questionnaire. The questionnaire included questions of past and present eye diseases, visits to ophthalmologists, use of glasses and other vision-related questions. The hyperopia was assessed by asking the patients to send their last prescription for glasses to the authors. Twins with any eye disease affecting refraction (cataract, corneal damage), operation or trauma to their eyes were discarded from the present study. In 191 pairs (80 monozygotic and 111 dizygotic pairs) one or both members of the pair had a hyperopic refractive error. The correlations of refraction between right and left eyes of both MZ and DZ pairs were high (Spearman Rank Correlations of 0.86-0.89). The intrapair correlations among MZ pairs were higher (0.44 for right and 0.45 for left eyes) than intrapair correlations among DZ pairs (0.24 for right and 0.15 for left eyes). The variances were not significantly different among MZ and DZ pairs. The classical analysis of heritability gave an estimate of 0.75 for hyperopia. The result suggests that genetic factors are important in hyperopia and especially in hyperopia of higher degree.

Adult↗
PubMed1989

Visual acuity outcome in isometropic hyperopia.

Refractive amblyopia may occur as a unilateral or bilateral condition. Although bilateral refractive amblyopia may account for 1 to 2% of all refractive amblyopia, there is little consistent information in the literature regarding isoametropic amblyopia resulting from bilateral hyperopia. Hence, this retrospective study investigated the prevalence of reduced aided acuity in patients aged 10 years and younger (mean age 3.97 years) with 5 D or more of isometropic hyperopia and considered the following factors that may influence visual acuity: (1) age at first correction; (2) magnitude of hyperopia; and (3) duration of refractive correction of the hyperopia. The results indicate that the majority of patients (87%) have aided acuity poorer than 6/6 at initial correction of refractive error. However, if the full hyperopic correction was worn for 1 year or longer, only 43% of these patients demonstrated acuity poorer than 6/6 and none showed acuity poorer than 6/12. The magnitude of the hyperopia appeared to have the greatest influence on the visual acuity outcome both at initial correction of refractive error and 1 year or longer after correction. Duration of correction also influenced the visual acuity outcome, but to a lesser extent than the magnitude of refractive error. In contrast, the age of first correction showed little correlation with visual acuity either at the time of first refractive correction or after a minimum of 1 year of correction.

Age Factors↗
PubMed1997

Photorefractive keratectomy for hyperopia after radial keratotomy.

BACKGROUND: Progressive hyperopia is a common complication following radial keratotomy. METHODS: Ten eyes of ten consecutive patients with hyperopia after radial keratotomy between +1.75 and +4.00 diopters (D) were treated with the hyperopia module of the Nidek Model EC-5000 excimer laser. The mean preoperative uncorrected visual acuity was 0.38 (20/60+). RESULTS: After excimer laser photorefractive keratectomy (PRK), mean uncorrected visual acuity improved to .72 (20/30+). No complications occurred with the exception of one eye with haze greater than 2+. CONCLUSION: PRK for hyperopia is a valuable method for correcting hyperopia after radial keratotomy.

Adult↗
PubMed1998

Laser in situ keratomileusis for hyperopia and hyperopic astigmatism.

BACKGROUND: The correction of hyperopia by excimer laser remains challenging because the procedure is followed by regression and loss of effect. We evaluated excimer laser in situ keratomileusis (LASIK) to correct hyperopia and hyperopic astigmatism using the NIDEK scanning slit excimer laser and a modified nomogram. METHODS: The study included the first consecutive 58 eyes treated for hyperopia and hyperopic astigmatism by one surgeon. All eyes were operated at the Alexandria Eye Center, Alexandria, Egypt using the Nidek excimer laser and the Chiron automated corneal shaper. Astigmatic correction was done first by myopic ablation using a 5.0 mm ablation zone and a 5.5 mm transition zone, followed by narrow hyperopic ablation using a 5.5 to 7.5 mm zone. RESULTS: Mean preoperative cycloplegic spherical equivalent refraction was +3.75 D (range, +1.00 to +6.00 D). Mean preoperative astigmatism was 2.75 D (range 0 to 4.00 D). After hyperopic LASIK, all eyes had a reduction in their hyperopia, but regression occurred gradually until the last follow-up examination. At 6 months follow-up, the mean cycloplegic refraction was +2.25 D (range, 0 to +3.25 D). The postoperative astigmatism had a mean of 1.25 D (range 0 to 2.75 D). Four eyes had a reduction in the quality of vision due to a decentered ablation and a small ablation zone, but no other vision threatening complications were reported. CONCLUSION: LASIK to correct hyperopia and hyperopic astigmatism is safe, effective, and repeatable. Predictability and long-term stability needs improvement. A better ablation profile and modified algorithm need to be provided by excimer laser manufacturers.

Adolescent↗
PubMedDate not supplied

Laser in situ keratomileusis for the correction of hyperopia from +0.50 to +11.50 diopters with the Keracor 117C laser.

PURPOSE: To evaluate excimer laser in situ keratomileusis (LASIK) for the correction of hyperopia. METHODS: We reviewed retrospectively the medical records of 46 patients treated with LASIK for hyperopia. All patients had a complete ophthalmologic evaluation. The corneal bed was ablated using the Bausch & Lomb Chiron Keracor 117C excimer laser to create a paracentral annular ablation under a nasally hinged 160-microm corneal flap with the Chiron Automatic Corneal Shaper microkeratome. Follow-up was a minimum of 6 months. RESULTS: Eighty eyes of 46 patients (23 males and 23 females) were included. Age ranged from 18 to 65 years (mean, 42 yr). The range of preoperative spherical equivalent refraction was +0.50 to +11.50 D (mean, +3.40 D). Mean postoperative spherical equivalent refraction at 6 months was +0.26 D. Six months after surgery, 35 eyes (44%) achieved uncorrected visual acuity of 20/20 or better and 78 eyes (97.5%) achieved 20/40 or better. Forty-six eyes (58%) had a postoperative spherical equivalent refraction within +/-0.50 D of attempted correction, and 67 eyes (84%) were within +/-1.00 D of attempted correction. When using the Bausch & Lomb Chiron Keracor 117C excimer laser to correct hyperopia, eyes with a spherical equivalent refraction less +2.00 D should be overcorrected by 25%, +2.00 to +4.00 D by 30%, and over +4.00 by 40%. The positive cylinder should be overcorrected by 10%. CONCLUSIONS: LASIK was safe and effective in the treatment of hyperopia from +0.50 to +11.50 D. Regression following LASIK for hyperopia remains a problem. A special nomogram was required to achieve results comparable with those for myopia.

Adolescent↗
PubMedDate not supplied

Wavefront aberration outcomes of LASIK for high myopia and high hyperopia.

PURPOSE: To determine the higher order aberrations at the corneal first surface after conventional LASIK for high myopia and high hyperopia. METHODS: This was a retrospective study using a convenience sample with subjects divided into five groups by level of refractive correction. Group 1 were normals, having no eye disease or previous surgery, but may have had refractive error. Group 2 had low myopia (-1.00 to -5.87 D), group 3 high myopia (> 6.00 D), group 4 low hyperopia (+1.00 to +3.87 D), and group 5 high hyperopia (> 4.00 D). LASIK was performed using a Technolas 217 laser. Corneal topography was taken with Orbscan II, and Placido data exported to VOLPro software v6.71. Wavefront aberrations were determined for a 6.0-mm pupil. RESULTS: The study included 264 subjects-group 1 (normal), n=204; group 2 (low myopia), n=20; group 3 (high myopia), n=20; group 4 (low hyperopia), n=10; and group 5 (high hyperopia), n=10. The spherical equivalent refractive error corrected (mean +/-SD) was 0.00 +/- 0.00 D in group 1, -3.92 +/- 1.47 D in group 2, -9.53 +/- 2.06 D in group 3, +2.49 +/- 0.51 D in group 4, and +5.54 +/- 1.22 D in group 5. The total higher order root-mean-square (RMS) wavefront aberration was 0.38 +/- 0.07 microm in group 1, 0.69 +/- 0.22 microm in group 2, 1.36 +/- 1.79 microm in group 3, 0.64 +/- 0.34 microm in group 4, and 1.76 +/- 0.54 microm in group 5. Spherical aberration was 0.25 +/- 0.06 mcirom in group 1, 0.45 +/- 0.11 microm in group 2, 0.64 +/- 0.29 microm in group 3, -0.11 +/- 0.15 microm in group 4, and -0.56 +/- 0.22 microm in group 5. The refractive correction (Rx) was highly correlated to total higher order RMS for myopic correction higher order RMS = 0.38 - 0.07 Rx, R2=0.52, and for hyperopic correction higher order RMS = 0.18 + 0.28 Rx, R2 = 0.75. CONCLUSIONS: Conventional LASIK increases all corneal higher order aberrations with induced aberrations increasing with the magnitude of refractive correction. High refractive corrections, both myopic (>6.00 D) and hyperopic (>5.00 D), can lead to very high levels of corneal higher order aberrations.

Astigmatism↗
PubMed2002

Volume estimation of excimer laser tissue ablation for correction of spherical myopia and hyperopia.

PURPOSE: To determine the theoretical volumes of ablation for the laser treatment of spherical refractive errors in myopia and hyperopia. METHODS: The cornea was modeled as a spherical shell. The ablation profiles for myopia and hyperopia were based on an established paraxial formula. The theoretical volumes of the ablated corneal lenticules for the correction of myopia and hyperopia were calculated by two methods: (1) mathematical approximation based on a simplified geometric model and (2) finite integration. These results were then compared for optical zone diameters of 0.5 to 11.00 mm and for initial radii of curvature of 7.5, 7.8, and 8.1 mm. RESULTS: Referring to a simplified geometrical model, the volume of ablated corneal tissue was estimated to be proportional to the magnitude of treatment (D) and to the fourth power of the treatment diameter (S(4)). For refractive correction of myopia and hyperopia, volume estimations using our formula, V congruent with D. (S/9)(4), were similar to those obtained by finite integration for optical zone diameters of 0.5 to 8.5 mm and for corneal radii of curvature within the clinical range (7.5, 7.8, and 8.1 mm). CONCLUSIONS: The theoretical volume of corneal tissue ablated within the optical zone for spherical corrections can be accurately approximated by this simplified formula. This may be helpful in evaluating factors that contribute to corneal ectasia after LASIK for myopia and hyperopia. Treatment diameter (S) is the most important determinant of the volume of tissue ablation during excimer laser surgery.

Cell Size↗
PubMed2005

[Occurrence of hyperopia among students ranging from 6 to 18 years of age].

PURPOSE: To determine the prevalence of hyperopia among students ranging from 6 to 18 years of age. MATERIAL AND METHODS: 5023 students from elementary schools, junior high schools and high schools, aged 6-18 years were examined. Measurements of visual acuity as well as retinoscopy after cycloplegia have been carried out. The data was analyzed using chi-square test, u-test and Student's t-test. RESULTS: It was found that 21% of the students, aged from 6 to 18 suffers from hyperopia. It has been observed that from the sixth to the eighteenth years of life along with the age decreases the prevalence of hyperopia. A major decrease in the frequency of hyperopia occurrence among students aged between 6 and 9 years old as well as among those aged 16 and older, has been found. Significant differences between prevalence of hyperopia among boys and girls was not observed.

Adolescent↗
PubMed1995

Intracranial hypertension and the syndrome of acquired hyperopia with choroidal folds.

An idiopathic syndrome of acquired hyperopia with choroidal folds has been characterized. Orbital imaging correlates of this syndrome include flattening of the posterior globe and distention of the perioptic subarachnoid space. The mechanism responsible for the clinical and radiographic findings of this syndrome is undefined. Two patients with unusual presentations of papilledema are reported whose clinical and radiographic findings were otherwise identical to those described in the idiopathic syndrome of acquired hyperopia with choroidal folds. One patient had unilateral disc edema and bilateral choroidal folds. The other patient had bilateral choroidal folds observed 2 years before he developed papilledema in both eyes. Both patients had intracranial hypertension, idiopathic in the first, and related to severe chronic obstructive pulmonary disease and cor pulmonale in the second. A third patient is also described who had typical clinical and orbital imaging findings of idiopathic unilateral acquired hyperopia with choroidal folds. He was also found to have mild intracranial hypertension. Intracranial hypertension can cause acquired hyperopia and choroidal folds and may be the underlying mechanism in some patients with what appears to be idiopathic acquired hyperopia with choroidal folds.

Adult↗
PubMed2003

[Laser in situ keratomileusis for correction of hyperopia and hyperopic astigmatism using a scanning spot excimer laser. Results of a prospective clinical study after 1 year].

PURPOSE: The purpose of this investigation was to evaluate the safety, efficacy, predictability, stability and complications of LASIK for the treatment of hyperopia and hyperopic astigmatism using a scanning spot excimer laser. PATIENTS AND METHODS: A total of 64 consecutive LASIK operations (37 patients, mean age 41 years, range 22-68 years) have been evaluated. The Hansatome microkeratome producing a superior hinge (flap diameter 9.5 mm) and a scanning spot excimer laser with an optical zone of 6.0 mm were used. Examinations were performed preoperatively, after 1 day, 7 days, 1 month, 4 and 12 months. RESULTS: One year after the primary procedure only 1 eye lost 2 or more lines of best-corrected visual acuity, 91% were within +/-1 line and 4 eyes gained 2 lines. Of these eyes 50 (86%) reached an uncorrected visual acuity of > or=0.5, 32 (55%) > or=0.8, 16 (28%) > or=1.0, 24 eyes (41%) needed a refractive correction of +/-0.5 D, 44 eyes (76%) of +/-1.0 D and 55 eyes (95%) of +/-2.0 D. The mean spherical equivalent after 1 year was +0.17+/-0.85 D. CONCLUSIONS: LASIK is suitable for the correction of hyperopia (up to a maximum of +5 D) and for hyperopic astigmatism (up to a maximum of -5 D). However, results were better in lower hyperopia (up to +3 D) than in the moderate hyperopia. The refractive results showed overall a good stability during the 12-month study period, but higher regression occurred in a few cases.

Adult↗
PubMed2005

Could personality traits modify the response to uncorrected high hyperopia?

PURPOSE: We aimed to measure temperament and investigate personality in children with high hyperopia considering that these could modify the individual response to uncorrected high hyperopia. METHODS: Fifteen children (age range, 5 to 12 years) with orthotropia and ametropic amblyopia in the presence of uncorrected high hyperopia were identified (group 1). Among the children with refractive accommodative esotropia, 15 children (age range, 5 to 12 years) were enrolled to form group 2. We measured the temperament by using the Children's Behavior Questionnaire (CBQ) Short Form. The Children's Apperception Test (CAT-H) was also administered to all subjects. RESULTS: Regarding the temperament scales measured by CBQ, themes of discomfort, fear, and shyness were more dominant in group 2; high-intensity pleasure and smiling-laughter were dominant in group 1. However the difference was statistically significant only for fear scale (P = 0.045). CAT-H results revealed that aggression toward the parents was the most commonly encountered behavioral pattern in both groups. The children in group 1 were more likely to express passive-aggressive behavioral pattern. Obstinacy and anal period characteristics dominate in the children in group 2. Themes of narcissistic injury was more frequently expressed by these children. CONCLUSION: The temperament scales and personality traits could play a role in the modification of the individual response to uncorrected high hyperopia. This finding deserves more research in a larger study group.

Child↗
PubMed2005

Long-term results of conductive keratoplasty for low to moderate hyperopia.

PURPOSE: To assess the long-term safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of low to moderate hyperopia and to evaluate the impact of the procedure on the quality of vision. SETTING: University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Crete, Greece. METHODS: In this prospective nonrandomized noncontrolled single-center study, 38 eyes of 26 patients (13 women and 13 men) were treated for hyperopia with a Refractec ViewPoint CK system and followed for 30 months. Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +1.89 diopters (D) +/- 0.6 (SD) (range +1.00 to +3.25 D), and the mean follow-up was 30.9 +/- 1.1 months. All eyes were treated with the regular CK nomogram for the treatment of spherical hyperopia. The treatment consisted of 8 to 32 spots applied to the periphery of the cornea. Mean age was 50.3 +/- 8.8 years (range 31 to 71 years). All treated eyes were analyzed for safety, efficacy, predictability, and stability. RESULTS: At 12 months, the MRSE was -0.06 +/- 0.8 D and at 30 months was -0.02 +/- 0.7 D. At 30 months, the mean MRSE was within +/-0.50 D in 68%, within +/-1.00 D in 92%, and within +/-2.00 D in all eyes. At 30 months, uncorrected visual acuity was 20/20 or better in 52.5% and 20/40 or better in 89% of eyes. No eye lost 2 or more Snellen lines or had an induced cylinder of 2.00 D or greater. The procedure did not cause statistically significant changes in contrast sensitivity. CONCLUSION: Results show that CK for low to moderate hyperopia is a safe, effective, predictable, and stable procedure.

Adult↗
PubMed1993

Children with exotropia responsive to spectacle correction of hyperopia.

A series of seven exotropic children (aged 2 to 10 years) had resolution of exotropia after spectacle correction of hyperopia. Their hyperopic correction ranged from 3.00 to 7.00 diopters. Six had intermittent exotropia, which became small-angle esophoria after spectacle correction. In one patient with apparently no fusion, spectacle correction converted constant exotropia to small esotropia in the monofixational range. In all patients, Worth 4-dot and Titmus Stereo Test results, when obtainable, indicated an improvement in binocular sensory status after correction of the hyperopia. We conclude that a trial of spectacle correction is warranted in exotropic children with severe hyperopia and in those with moderate hyperopia and a low accommodative convergence/accommodation ratio or evidence of hypoaccommodation.

Child↗
PubMed1996

Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty. Clinical study with two-year follow-up.

BACKGROUND: Thermal keratoplasty to correct hyperopia has been attempted with nonlaser and laser devices. Problems have included long-term regression and irregular induced astigmatism. The present clinical study was performed to investigate the safety, efficacy, and stability of a noncontact mode of holmium: YAG laser energy delivery and a modified laser thermal keratoplasty treatment procedure for correction of low hyperopia. METHODS: Seventeen patients underwent noncontact holmium: YAG laser thermal keratoplasty in their nondominant eyes for correction of hyperopia of up to 3.00 diopters. Treatment parameters included simultaneous delivery of eight holmium: YAG laser spots in a symmetrical octagonal array with a centerline diameter of 6mm, 10 pulses of laser light at 5-Hz pulse repetition frequency, and pulse energies of 159 to 199mJ. Follow-up was 2 years in 15 of 17 patients. RESULTS: In the 15 eyes examined at 2 years after surgery, mean uncorrected distance Snellen visual acuity improved from 20/125-1 to 20/50-2. The mean change in spherical equivalent of subjective manifest refraction was -0.79 diopter. Eleven of these 15 eyes (73%) had a mean refractive correction of -1.1 diopters (range, -0.38 to -2.63 diopters); regression between 14 days and 2 years was 0.2 diopter. Four eyes (27%) had no persistent refractive correction (within +/- 0.25 diopter). Mean induced refractive astigmatism was 0.18 diopter. None of the eyes lost two or more lines of spectacle-corrected distance vision. The amount of refractive correction at 2 years after surgery was correlated to the treatment pulse energy and the volume of the opacified corneal tissue observed immediately after treatment. CONCLUSIONS: This technique of noncontact laser thermal keratoplasty produced safe, effective, and persistent corrections of low hyperopia in the majority of treated eyes.

Aged↗
PubMed1997

Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty: U.S. phase IIA clinical study with 2-year follow-up.

PURPOSE: This study was performed to determine the long-term efficacy, safety, and stability of noncontact holmium:yttrium aluminum garnet (Ho:YAG) laser thermal keratoplasty (LTK) for correction of low-to-moderate hyperopia. METHODS: The authors treated 1 eye each of 28 patients for correction of low-to-moderate hyperopia (up to +3.88 diopters [D] refractive error) using the Sun 1000 Corneal Shaping System (Sunrise Technologies, Inc., Fremont, CA). Treatments were performed with one or two rings of eight spots per ring with centerline diameters of 6 mm (one ring) or 6 and 7 mm (two rings), ten pulses of laser light at 5-Hz pulse repetition frequency, and pulse energies ranging from 208 to 242 mJ. Follow-up was 2 years. RESULTS: At 2 years after surgery, uncorrected distance visual acuity was improved by 1 or more lines of Snellen visual acuity in 19 (73%) of 26 of the treated eyes. The mean lines gained was 2.5 +/- 2.2/3.3 +/- 2.7 for one- and two-ring treatment groups, respectively. The mean change in spherical equivalent of the subjective manifest refraction was -0.53 +/- 0.33 D/-1.48 +/- 0.58 D for one- and two-ring treatment groups. Regression between 1 and 2 years was 0.01 D and 0.16 D, respectively. In the one-ring treatment group (18 eyes), 13 eyes (72%) had refractive corrections (range, -0.38 to -1.13 D), and 5 eyes (29%) were unchanged (within +0.25 D) relative to their preoperative measurements. In the two-ring treatment group, all eight eyes (100%) had reductions in their hyperopia (range of corrections, -0.38 to -2.25 D). None of the eyes lost two or more lines of spectacle-corrected distance visual acuity. There were no sight-threatening complications. CONCLUSIONS: This initial U.S. clinical study indicates that noncontact laser thermal keratoplasty treatment of low hyperopia is safe and produces modest but persistent corrections with 2-year follow-up. Expanded studies of this treatment method are warranted.

Adult↗