Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “refractive error”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1988

Diagnostic and therapeutic technology assessment. Radial keratotomy for simple myopia.

There was a lack of consensus among DATTA panelists about the safety and, especially, the effectiveness of radial keratotomy. For patients with a preoperative refractive error greater than -6.00 D, DATTA panelists believed that radial keratotomy has not been established as safe or effective. Concerns about effectiveness focused on the lack of predictability of the results and the continuing change in the refractive error following surgery. Daily fluctuations in visual acuity and the occurrence of anisometropia were other reported adverse events that contributed to the concern expressed by DATTA panelists. Concern over the safety and effectiveness of the procedure became greater as the magnitude of the preoperative refractive error increased. Nevertheless, there is a subpopulation of myopic patients who regard their myopia as a sufficiently severe handicap for them to undergo radial keratotomy. Such carefully chosen patients who have the procedure performed may achieve emmetropia and be free of corrective lenses.

American Medical Association↗
PubMed1996

Prevalence of ocular disorders among 6- and 7-year-olds in Santa Monica, California.

BACKGROUND: Undetected ocular disorders can cause serious problems in a child's mental and social development. METHODS: To investigate relationships between ocular disease, gender and ethnicity in children, vision screening examination data was analyzed from the UCLA Mobile Eye Clinic (MEC), collected from 1985 to 1990 on first graders (69.9 percent 6- and 30.1 percent 7-year-olds) in Santa Monica, California. RESULTS: The sample consisted of 1,469 individuals, of whom 48.1 percent were female and 51.9 percent were male. Ethnicity data was available from 1988 to 1990 on 834 individuals, of whom 46.9 percent were Hispanic, 27.9 percent were White. 11.5 percent were Black, 4.4 percent were Asian, and 9.2 percent were of other races. Significantly more females than males had refractive errors, specifically hyperopia and astigmatism, and uncorrected visual acuity of 20/50 or worse in at least one eye. There were no significant associations of ethnicity or sex with any other disease category. The overall prevalences of other diseases were less than 4 percent. Of the 6- and 7-year-olds studied in Santa Monica, California, 18.5 percent had refractive errors. CONCLUSIONS: Screening for ocular disorders at an early age allows for detection of problems, especially refractive errors, that might affect school performance if uncorrected.

California↗
PubMed1996

[Sensitivity loss in short wavelength sensitive cones in myopic eyes].

To investigate early changes of visual function in high myopic eyes, the relative sensitivity of the short-wavelength sensitive cones (s-cones) was measured by flash-evoked cortical potentials and electroretinograms and their relation with refractive error and axial length of the eyes was studied. A Ganzfeld stimulus was employed. The subjects were all under 37 years of age and were divided into 3 groups according to the magnitude of the refractive error as follows; 1) emmetropia/low myopia group (10 eyes), between +0.50 D and -3.00 D; 2) medium myopia group (8 eyes), between -3.25 D and -6.00 D; and 3) high myopia group (10 eyes), over -6.25 D. Their corrected visual acuities were better than 1.0 and their color vision was normal according to Panel D-15 and SPPII. They had no other ophthalmological abnormalities except tigroid fundus. The s-cone sensitivity was significantly correlated with the refractive error and axial length (p < 0.001) and was reduced prior to ophthalmoscopic retinal changes in the medium and high myopia groups. This indicates that the site of s-cone sensitivity loss in myopia is in the retinal.

Adolescent↗
PubMedDate not supplied

Phakic intraocular lenses.

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.

Humans↗
PubMed1987

Thermal gradients in the chick eye: a contributing factor in experimental myopia.

Domestic chicks were reared for 4 weeks with a plastic dome or a plastic ring glued to the skin surrounding the right eye. The domes, which degraded retinal images by reducing high spatial frequencies and contrast, have been reported to produce enlargement of the ocular globe and large myopic refractive errors. The rings, which do not produce refractive errors, did not affect vision and served as a control for the mechanical effects of having a device glued to the circumorbital skin. At the end of the rearing period, the chicks were anesthetized and a thermoprobe (a thermocouple in a 29 gauge needle) was inserted into the eye along the optic axis. Temperature readings were made at 1 mm intervals to a depth of 12 mm. Temperature readings also were taken of the circumorbital skin and the air inside the dome. The results indicated that the temperature in the dome eyes was elevated from 2.8 to 5.2 degrees C at the cornea and 0.7 to 2.0 degrees C at the axial sclera. Smaller elevations were found in the ring eyes. Two dome chicks that had lost their devices 24-48 hr prior to temperature measurement had thermal gradients that were nearly identical to those from untreated control eyes. Measurement of the air temperature inside the dome revealed a temperature elevation of nearly 4.0 degrees C above that recorded at an equal distance from control eyes. The circumorbital skin of treated eyes was 0.96 degrees C warmer than the comparable tissue of untreated eyes.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1997

Blindness and low vision in Jimma Zone, Ethopia: results of a population-based survey.

A population-based study on the prevalence of blindness and low vision was carried out in Jimma Zone, south-western Ethiopia between November 1994 and January 1995. A total of 7423 people from a sample of 8215 (90.4%) was examined. Sixty-three (0.85%) were blind (visual acuity less than 3/60 in the better eye) and 125 people (1.7%) had low vision (less than 6/18-3/60). Cataract and aphakia (52.4%), corneal opacity and phthisis bulbi (25.4%), and glaucoma (9.5%) were the major causes of blindness. Cataract (56.8%), refractive errors (28.8%), and corneal opacity (12.8%) were the major causes of low vision. Corneal opacity from trachoma was responsible for 20.6% of all blindness and 10.4% of low vision. The prevalence of visual impairment due to refractive errors was 5.1/1000 population. Almost 25% of the study population had active trachoma, and 0.9% of pre-school children had signs of vitamin A deficiency. Out of a total population of 2 million an estimated 17,000 people are blind and 34,000 have low vision (i.e., a total of 51,000 people with visual impairment). Approximately 20,000 people require cataract surgery, 52,000 require lid surgery for trichiasis, 24,000 require spectacles (excluding presbyopia), including 10,000 for significant refractive errors, half a million require treatment for active trachoma and 4,000 require glaucoma treatment. Effective and feasible eye care programs need to be established in the zone and the available ophthalmic services have to be strengthened. These may be achievable through joint efforts of the community and the Ministry of Health in collaboration with non-governmental organizations. The available eye services are briefly described and recommendations made to meet the important needs for prevention of blindness in the region.

Adolescent↗
PubMed2004

[Effect of adjustment of corneal running sutures on cylindrical refraction after perforating keratoplasty].

Authors refer about the effect of adjusting (adjustment of the suture tension) of the running corneal suture on the final cylindrical refraction in patients who underwent penetrating keratoplasty due to keratoconus. In our article we evaluate two groups of patients. The group I consists 76 patients (76 eyes) who regularly visited our department of ophthalmology. There were 52.6% of females and 47.4% of males. The average age at the time of surgery was 33.5 +/- 5.2 years (range, 18-52 years). In this group of patients, the adjusting was performed during the surgery. In the group II 35 patients (40 eyes) underwent the adjusting procedure of the running corneal suture in the early postoperative period. There were 19 (54.0%) women and 16 (46.0%) men. The average age of the whole group at the time of surgery was 34.6 +/- 3.8 years (range, 18-50 years). The indication to carry out the adjusting was topographically verified astigmatism of more then 3.5 cylindrical diopters (D cyl). The purpose of this study was to find the ultimate surgery technique to get not only the clearness and good healing of the corneal graft, but first of all to prevent extensive ametropia already during the surgery. In the early stage after the surgery we are trying to reduce emerged refractive error and to get faster recovery of good visual acuity of the operated eye. In the sense of the least final postoperative astigmatism, the best results we have reached in cases where the donor corneal graft was 0.25 mm larger in diameter and the suture was adjusted during the surgery using light circles according to Serdarevic. In this group of patients the average final cylindrical refractive error after the surgery was 2.00 +/- 0.81 D cyl. When adjusting the corneal suture in postoperative period, the mean final refractive error decreased of about 3.09 +/- 1.62 D cyl.

Adolescent↗
PubMed2000

Choroidal thickness changes during altered eye growth and refractive state in a primate.

PURPOSE: In the chick, compensation for experimentally induced defocus involves changes in the thickness of the choroid. The choroid thickens in response to imposed myopic defocus and thins in response to imposed hyperopic defocus. This study was undertaken to determine whether similar choroidal changes occur in the primate eye with induced refractive errors. METHODS: Thirty-three common marmosets were used. Eyes in 26 monkeys served as untreated control eyes, and eyes in 7 received 3 weeks of monocular lid suture to induce changes in eye growth and refractive state. Refractive errors were measured using refractometry and retinoscopy, and axial ocular dimensions, including choroidal thickness, were measured using high-frequency A-scan ultrasonography. Eyes were measured before the lids were sutured and at frequent intervals after lid opening. RESULTS: In the marmoset, choroidal thickness ranges from 88 to 150 microm and increases significantly during the first year of life. Monocular lid suture initially results in short, hyperopic eyes that then become elongated and myopic. In these animals the choroids of both the experimental and the fellow control eyes also increase in thickness with age but additionally show interocular differences that vary significantly with the relative changes in vitreous chamber depth and refraction. In eyes that are shorter and more hyperopic than control eyes the choroids are thicker, and in eyes that are longer and more myopic than control eyes the choroids are thinner. CONCLUSIONS: In marmosets, the thickness of the choroid increases during postnatal eye growth. Superimposed on this developmental increase in choroidal thickness there are changes in thickness that are correlated with the induced changes in eye size. These changes are small (<50 microm) in comparison with those observed in the chick, contributing to less than a diopter change in refractive error.

Aging↗
PubMed2004

The average eye.

For statistical and other purposes one needs to be able to determine an average eye. An average of refractive errors is readily calculated as an average of dioptric power matrices. A refractive error, however, is not so much a property of the eye as a property of the compensating lens in front of the eye. As such, it ignores other aspects of the optical character of the eye. This paper discusses the difficulties of finding a suitable average that fully accounts for the first-order optics of a set of optical systems. It proposes an average based on ray transferences and logarithms and exponentials of matrices. Application to eyes in particular is discussed.

Eye↗
PubMedDate not supplied

Comparison of minus power anterior chamber intraocular lenses and myopic epikeratoplasty in phakic eyes.

We performed a retrospective study of two sequential series of operations designed to correct high myopia in phakic eyes. The first series consisted of 21 eyes with refractive error ranging from -11.00 diopters to -21.00 D (mean -16.9 D). They received a commercially prepared, lyophilized, myopic epikeratoplasty lenticule sutured into a circular keratectomy. Seven lenticules had to be removed within the first year because of poor refractive results, corneal ulceration, or melting. The nine eyes followed from 12 to 24 months after surgery demonstrated residual refractive errors from +4.00 D to -11.25 D. We also studied an initial series of 41 eyes with preoperative myopia ranging from -9.00 D to -35.00 D (mean -15.00 D) that received a minus power anterior chamber intraocular lens. The lens had an open loop design with an anterior vault, four point angle fixation, and an optic diameter of 4.5 mm. Recovery of visual acuity was faster with the intraocular lens than with epikeratoplasty. Three intraocular lenses were removed; two because they were the wrong size and one because it was the wrong power. Two of the lenses were replaced with acceptable results. Of the 34 eyes followed for 12 months, all had a residual refractive error within +/- 2.00 D of emmetropia. During the short-term follow-up, no elevated intraocular pressure, cataract formation, or excessive endothelial damage was observed. We concluded that anterior chamber minus power intraocular lenses gave more rapid and predictable optical correction in high myopic eyes than did myopic epikeratoplasty. Longer follow-up is required before conclusions can be reached about the safety of these intraocular lenses.

Adolescent↗
PubMed1997

Multifocal electroretinogram in myopia.

PURPOSE: To investigate early changes of retinal function in myopic eyes, patients with various degrees of myopia underwent multifocal electroretinography (multifocal ERG). METHODS: Thirty young patients (mean age, 26.1 years) were divided into three groups according to the degree of refractive error: emmetropia/low, medium, and high myopia. All groups were matched by sex and age. All subjects had good corrected visual acuities of better than 1.0 and normal color vision. No other ophthalmoscopic abnormalities except for tessellated fundus existed. Three grouping programs (all-traces, rings, and quadrants) were used, and all-traces grouping waveforms, six-ring grouping waveforms, and four-quadrant grouping waveforms were determined from 103 local responses. We studied the differences of amplitudes and latencies of the waves among the myopic groups and their relation to refractive error and axial length. RESULTS: Amplitudes were reduced and latencies were delayed as the refractive errors increased. The amplitudes in the peripheral areas were more reduced in the myopic groups. CONCLUSIONS: The reduced amplitude and delayed latency of each wave of multifocal ERG in myopia resulted primarily from cone function loss, which may occur even when the only noted retinal change is tessellated fundus.

Adult↗
PubMed1991

[Development of impaired vision in mentally handicapped children].

The aim of the following study was 1) to show the incidence of ophthalmic disorders in severely visually and mentally handicapped children retrospectively 2) to follow up the change in visual acuity over at least 2 years prospectively 3) to look at the effect of therapeutic concepts. 270 children of the "Blindeninstituts-stiftung Würzburg" were followed up between 1960 and 1987. ad 1) Optic atrophy was the leading cause of visual impairment (24%) followed by cataract and retinopathy of prematurity (both found in 17%), malformations of the anterior segment (12%), cortical amblyopia (8%) and refractive error (6%). Strabismus was an additional finding in 38% of the children often associated with nystagmus. Convergent and divergent strabismus had the same incidence. ad 2) Visual acuity improved in 30% of cases of cortical amblyopia, in 40% of refractive errors and in 30% of optic atrophy. In cases of cataract there was a slight improvement in 20%. In 24% of aphakia a secondary glaucoma was observed. In cases of malformations of the anterior segment and ROP the visual acuity remained stable on a low level. The cases of ROP were advanced and had not received any surgical treatment. A deterioration in vision as often seen after surgical intervention was observed in 20% of ROP. In respect of the high incidence of refractive errors and orthoptic problems in multiple handicapped children they should be seen as early as possible by an ophthalmologist. Detection of a congenital cataract soon after birth as well as complications of other disorders should help to prevent blindness. The remaining visual perception is especially important for the handicapped child to communicate and move about.

Adolescent↗
PubMed2005

Reduction of myopia from corneal refractive therapy.

PURPOSE: : The purpose of the study was to monitor the efficacy of corneal refractive therapy (CRT) lenses to reduce myopia over a 4-week period. Refractive error, keratometry, high and low contrast acuity, and subjective vision after 28 days of using CRT contact lenses were measured. METHODS: : Twenty-three myopes wore CRT HDS lenses, Dk = 100. The Nikon autokefractor/keratometer was used to measure the refractive error and keratometric changes. Visual acuity was measured using computerized high and low contrast charts and the subjects completed visual analog scales characterizing their vision on a daily basis. Measurements were performed at baseline (before lens insertion before sleep), immediately after lens removal the next morning and at 1, 3, 7, and 14 hours after eye opening. Measurements were made on the days following 1, 4, 10, and 28 nights of lens wear. After 72 hours of no lens wear, these parameters were again measured to assess corneal recovery. RESULTS: : The pretreatment manifest refraction (mean of OD and OS +/- standard deviation [SD]) was -2.72 DS +/- 1.06 and -0.55 DC +/- 0.40. Myopic spherical equivalent refractive error (+/- SD) decreased by 1.30 DS +/- 0.53 (range 0-3 D) immediately after lens removal on day 1 and by 2.59 DS +/- 0.77 by day 28 (range 1.25-3.88 D). The cylinder remained unchanged. Uncorrected visual acuity improved by 5 lines after one night and reached 0.00 LogMAR (6/6) by day 4. Visual acuity was maintained throughout the day by day 10. The day and time effect of the spherical equivalent change and the central corneal radius of curvature were statistically significant (p < 0.01) up to day 10 and remained the same until day 28. Central (autokeratometer) Ks flattened by 1.28 D +/- 1.35 after one night and 2.33 D +/- 1.30 by day 28. The subjective vision improved significantly from day 1 to day 28 (p < 0.01) and was maintained throughout the day from day 4 to day 28 (p < 0.01). All measures did not recover completely to baseline after 72 hours of no lens wear. CONCLUSIONS: : CRT lenses significantly reduced myopia, improved visual acuity and subjective vision, and flattened central corneal curvature. Maximal effect was achieved after 10 days and was maintained for the rest of the study period.

Adult↗
PubMed2006

Characteristics of highly myopic eyes: the Beijing Eye Study.

OBJECTIVE: To evaluate factors associated with high myopia (defined as a myopic refractive error exceeding -8 diopters) in a population-based study. DESIGN: Population-based prevalence study. PARTICIPANTS: The Beijing Eye Study included 4439 participants from among 5324 individuals from a rural area and an urban region of Greater Beijing, > or =40 years old and invited to participate (response rate, 83.4%). METHODS: Interview and detailed ophthalmic examination. MAIN OUTCOME MEASURES: Refractive error, microvascular retinal abnormalities, optic disc morphometry, amount of cataract, and age-related macular changes. RESULTS: Fundus photographs and data for refractive error were available for 4319 participants (97.3%; 8484 eyes). In binary logistic regression analysis, prevalence of high myopia was significantly associated with low best-corrected visual acuity (P<0.001; 95% confidence interval [CI], 0.15-0.40), large optic disc size (P<0.001; 95% CI, 1.64-2.25), large size of beta zone (P = 0.31; 95% CI, 1.45-1.75) and alpha zone of peripapillary atrophy (P<0.001; 95% CI, 1.20-1.58), and lower macular drusen count (P = 0.020; 95% CI, 0.81-0.98). The highly myopic group had a smaller mean size of macular drusen (P = 0.03; 95% CI, 0.02-0.26) and a smaller area covered by drusen (P = 0.01; 95% CI, 0.03-0.22). In the highly myopic group, the predominant drusen type was significantly (P = 0.01; 95% CI, 0.05-0.41) more often the hard distinct drusen type than the soft drusen type, and visual field defects were significantly more common (P<0.001; odds ratio [OR], 24.0; 95% CI, 13.9-41.4) and larger (P<0.001; 95% CI, -1.67 to -1.13). The frequencies of early macular degeneration (P = 0.03; OR, 3.0; 95% CI, 1.21-7.51) and late macular degeneration (P<0.001; OR, 6.33) were significantly lower in the highly myopic group than in the non-highly myopic group. High myopia was not significantly associated with gender (P = 0.18; 95% CI, 0.76-1.05), focal arteriolar thinning (P>0.35), arteriolar sheathing (P>0.45), arteriovenous crossing abnormalities (P>0.20), self-reported diagnosis of diabetes mellitus (P = 0.54; OR, 1.36; 95% CI, 0.48-3.80), or arterial hypertension (P = 0.34; OR, 0.66; 95% CI, 0.32-1.34). CONCLUSIONS: In the adult Chinese population, high myopia is associated with a lower number, smaller, size and less advanced type of macular drusen, a larger optic nerve head, and decreased best-corrected visual acuity. The risk of early and late macular degeneration was lower for highly myopic participants than for non-highly myopic participants.

Adult↗
PubMed2004

[A comparison study of pulsitile ocular blood flow in normal eyes and primary open angle glaucoma].

OBJECTIVE: To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) in primary open angle glaucoma (POAG) and normal control group matched for age, sex and refraction error, to investigate the rule of hem-dynamics in POAG and to determine the sensitivity and specificity of POBF measurement as a diagnostic test for glaucoma. METHODS: Prior to the test a questionnaire was completed to determine age, sex, refractive error, family history of glaucoma, history of eye diseases, ocular medication, medical history and using of systemic beta-blockers. Patients of POAG were determined by following diagnostics standards: (1) Three IOP >25 mm Hg in different times of one day. (2) The fluctuate of IOP > 8 mm Hg during 24 hours. (3) Typical glaucoma changes in the visual field. (4) Typical glaucoma changes in optic disc. There were 100 POAG subjects with single eye observed (50 male and 50 female). We picked up 100 eyes randomly (50 male and 50 female) in 534 normal persons who matched for following conditions: (1) Sex. (2) Discrepancy of age less than 5 years. (3) Discrepancy of the refraction error less than +/- 2.00 DS. as the normal comparison group. The tonometer used was the POBF Tonometry. Pulse amplitude of IOP (PA), pulsatile ocular blood flow (POBF), pulse/heart rate (PR), maximum-IOP (max-IOP), minimum-IOP (min-IOP) and average IOP (aver-IOP) were obtained before the medical therapy and 1 or 2 weeks after the operation. The correlation between the POBF & mean value of the perimeter was analyzed. POBF was analyzed to determine the sensitivity and specificity of POBF measurement as a diagnostic test. RESULTS: The value of POBF in POAG and normal control was (9.72 +/- 3.47) microl/s and (12.04 +/- 4.68) microl/s, respectively. POAG patients' POBF, PV, PA, and AVE-IOP were less than those in the normal control, and the difference was statistically significant. There was no statistically significant correlation between the changes of visual field and POBF (r = 0.224, P = 0.219). The sensitivity and specificity of using the POBF for diagnosis of POAG (less than 10.75 microl/s being abnormal) were 0.422 and 0.623, respectively. CONCLUSION: Abnormal of vas-autoregulation and blood supply play a role in the pathogenesis of POA. Due to the lower sensitivity and specificity, it is not suitable to use POBF as a diagnostic test to distinguish the POAG and normal. But the POBF reflects the change of blood flow in a pulsing cycle and provide more information than the measurement of IOP only.

Age Factors↗
PubMed1994

The effect of parental history of myopia on children's eye size.

OBJECTIVE: To evaluate whether eye size and shape are different in children based on their parental history of myopia. DESIGN: A community-based cohort study of schoolchildren (aged 6 to 14 years), the Orinda (Calif) Longitudinal Study of Myopia. SETTING: Four campuses of the Orinda Union School District, a predominantly white, high socioeconomic status community. PARTICIPANTS: A cross-sectional volunteer sample of 716 children (662 non-myopic) in the first, third, and sixth grades in 1989, 1990, and 1991. All children in those grades were eligible for inclusion in the study. INTERVENTION(S): None. MAIN OUTCOME MEASURES: Refractive error (measured by autorefraction), corneal curvature (measured by photokeratoscopy), crystalline lens power (measured by video phakometry), and axial ocular dimensions (measured by ultrasonography). RESULTS: With prevalent cases of myopia excluded and grade in school and "near work" controlled for, children with two myopic parents had longer eyes and less hyperopic refractive error (analysis of covariance, P < or = .01) than children with only one myopic parent or no myopic parents. A model incorporating parental history is only improved by the addition of near work for the prediction of refractive error. CONCLUSIONS: Even before the onset of juvenile myopia, children of myopic parents have longer eyes. These results suggest that the premyopic eye in children with a family history of myopia already resembles the elongated eye present in myopia.

Adolescent↗
PubMedDate not supplied

Long-term follow-up of pediatric epikeratophakia.

BACKGROUND: Epikeratophakia is a potentially reversible corneal surgical procedure that can correct refractive errors in children who are aphakic and poor candidates for intraocular lens implantation. The correction of aphakia in the pediatric population poses specific problems because of associated amblyopia. METHODS: The clinical records of 61 consecutive patients (82 eyes) treated for pediatric aphakia by epikeratophakia were reviewed retrospectively with a follow-up of 3 to 5 years. For the purpose of analysis, the patients were divided into seven groups. RESULTS: The overall success rate for epikeratophakia was 92%, but with repeated surgery, the patient success rate was 93%. The average refractive error at 1 year was + 0.10 diopters (D). At 1 year, 68% of eyes had a refraction within 1 D of emmetropia. In these growing eyes, we documented an average myopic shift of -0.40 D during 4 years. A myopic shift occurred in 30.2% and a hyperopic shift in 9.4% of eyes. Spectacle-corrected visual acuity at 3 years showed 36% of eyes seeing 20/40 or better. Visual acuity results in different groups varied with the timing of epikeratophakia, density of amblyopia and parents' ability to maintain the patching schedule. The most encouraging results came from the treatment of monocular traumatic cataracts. In this group, 31% achieved visual acuities of 20/40 or better and 85% achieved 20/100 or better at final examination. Those with incomplete congenital cataracts also showed favorable results: 39% achieved 20/40 or better at final examination. CONCLUSIONS: Follow-up of 3 to 5 years demonstrated that epikeratophakia can correct refractive errors safely and successfully in aphakic children, either as a primary procedure, or as a secondary procedure after cataract extraction.

Adolescent↗
PubMed2002

Overnight orthokeratology: preliminary results of the Lenses and Overnight Orthokeratology (LOOK) study.

BACKGROUND: The Lenses and Overnight Orthokeratology (LOOK) study is a pilot study designed to learn the procedures of orthokeratology lens fitting in preparation for a planned larger clinical trial and to obtain data with which to calculate a sample size for that larger study. Data are presented for the first 3 months of the LOOK study. METHODS: Sixty subjects were enrolled in this multicenter pilot study to evaluate the success and safety of treatment with overnight orthokeratology contact lenses. Refractive error, corneal topography, and biomicroscopic data were collected to determine the amount of refractive error change achieved, corneal changes, and a safety profile of overnight wear of reverse geometry rigid gas permeable lenses for orthokeratology. RESULTS: Of the 60 subjects enrolled, 46 completed the 1-month visit, and 31 completed the 3-month visit. The mean change in spherical equivalent manifest refraction from baseline to the morning 3-month visit was 2.08 +/- 1.11 D in the right eye and 2.16 +/- 1.05 D in the left eye. At the 3-month morning visit, 74% of right eyes and 61 % of left eyes had 20/20 unaided visual acuity. No corneal infiltrates or ulcers were noted in any subjects. Observations of fluorescein staining of the cornea, imprinting, and microcysts were noted in some patients at the 3-month visit. CONCLUSIONS: The preliminary results of the LOOK study indicate that improvement in unaided visual acuity can be attained for at least 6 h after lens removal. The short-term safety and efficacy of the procedure appear to be favorable; however, future studies are needed to determine the long-term outcomes of treatment.

Contact Lenses↗