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PubMed1994

Asthenopia and the dark focus of accommodation.

To study asthenopia, we compared the dark focus of accommodation of 54 symptomatic and 56 asymptomatic control subjects. The two groups were matched for age and cycloplegic refractive error. Symptomatic subjects were defined as those who complained of asthenopia daily even though their refractive error had been corrected. Subjects with other eye diseases that could produce asthenopia such as strabismus or aniseikonia were excluded. Using a Nidek Autorefractometer AR1600, we first measured non-cycloplegic refractive error (Non-Cyclo R) in a bright room, then the dark refractive state (Dark R) in complete darkness using the instrument with the optical target light extinguished and, finally, determined the cycloplegic refractive error (Cyclo R) after instilling cyclopentolate hydrochloride. The difference between Dark R and Cyclo R was defined as DFcus (Cyclo R) and that between Dark R and Non-Cyclo R as DFcus (Non-Cyclo R). We found both DFcus (Cyclo R) and DFcus (Non-Cyclo R) to be smaller in the symptomatic than in the asymptomatic subjects, indicating that asthenopia is associated with a low rather than a high level of tonic accommodation.

Accommodation, Ocular↗

PubMed1991

Properties of the feedback loops controlling eye growth and refractive state in the chicken.

Recent experiments in chickens provide evidence that axial eye growth and refractive state are guided by mechanisms sensitive to refractive error. To determine whether or not the sign of refractive error is derived from longitudinal chromatic aberration we raised chicks with spectacle lenses in monochromatic light. The eyes showed an appropriate growth response to correct for the defocus imposed by the lenses no different than in previous experiments in white light. Thus, in normally accommodating chicks chromatic cues are not necessary for emmetropization to occur. We examined the linearity of feedback loops controlling axial eye growth: positive spectacle lenses were found to inhibit axial growth very efficiently making the eyes shorter than normal whereas negative lenses had little effect on axial elongation: feedback loops for regulation of axial growth are highly nonlinear and act most efficiently on the myopic side. We found that, subsequent to a period of binocular deprivation of form vision, the refractive errors acquired are highly correlated in both eyes. Since both eyes grew without visual feedback we conclude that the gains in the feedback loops that control axial growth must be similar in both eyes. We suggest that the gains are genetically determined and are typical for each individual. Chicks made near-sighted in both eyes by "deprivation of form vision" were corrected by appropriate negative lenses. Three out of five chicks recovered from myopia despite the correction. Also two chicks that were made near-sighted in one eye recovered with no regard to the correcting lens. Three chicks remained more myopic than the correcting lens required and finally started to recover while the lens was still in place. Two out of three chicks that were made far-sighted showed recovery despite appropriate correction by positive lenses. We conclude that there must be a nonvisual mechanism highly sensitive to abnormal eye shape. During expt (4) we found unexpectedly that the development of form deprivation myopia is inhibited if no part of the retina in an animal is exposed to normal visual experience. The result indicates that some communication between both eyes exists, although form deprivation myopia itself has been shown to develop independently in both eyes.

Animals↗

PubMed2003

Ocular component data in schoolchildren as a function of age and gender.

PURPOSE: To describe the refractive error and ocular components of a large group of school-aged children as a function of age and gender. METHODS: In this report, we describe the refractive error and ocular components of 2583 school-aged children (49.3% girls, overall mean [+/-SD] age 10.0 +/- 2.3). Measurement methods included cycloplegic autorefraction, autokeratometry, videophakometry, and A-scan ultrasonography. For statistical comparisons across gender and age, a critical point of alpha = 0.005 was used to assess significance because of the large sample size and the large number of comparisons made. RESULTS: Of these 2583 children, 10.1% were myopic (-0.75 D or more myopia in both meridians), and 8.6% were hyperopic (+1.25 D or more hyperopia in both meridians). As would be expected, there was a significant effect of age on refractive error (spherical equivalent, p < 0.0001), toward less hyperopia/more myopia. There was no significant difference in the average refractive error between girls and boys (p = 0.0192). Girls had steeper corneas than boys (0.74 D steeper in the vertical meridian and 0.63 D steeper in the horizontal meridian, p < 0.0001). There were no significant differences in corneal power with age (p = 0.16). Both older age and male gender were significantly associated with deeper anterior chambers (p < 0.0001 for both). The crystalline lens showed significant thinning with age (p < 0.0001), however, there was no significant difference in the lens thickness between girls and boys (p = 0.66). Both Gullstrand lens power and calculated lens power showed significant effects of age and gender (p < 0.0001 for both). Girls, on average, had Gullstrand lens powers that were 0.28 D steeper and calculated lens powers that were 0.80 D more powerful than boys. Axial length also showed significant effects of age and gender (p < 0.0001 for both). Girls' eyes were, on average, 0.32 mm shorter than those of boys. CONCLUSIONS: These cross-sectional data show a general pattern of ocular growth, no change in corneal power, and crystalline lens thinning and flattening between the ages of 6 and 14 years. Girls tended to have steeper corneas, stronger crystalline lenses, and shorter eyes compared with boys.

Adolescent↗

PubMed2002

Long-term visual outcomes in the Cataract-Free Zone Project in Brazil.

PURPOSE: To determine the long-term visual outcomes and causes of poor vision in the cataract population in Brazil treated in the Cataract-Free Zone Project. METHODS: Project A subjects (62 patients) were recruited in Taquaritinga, SP, 26 months after surgery. Project B subjects (34 patients) were recruited in São João da Boa Vista, SP, 43 months after surgery. All patients underwent visual screening and eye examination (examination 1). They were classified according to visual acuity in the operated eye and the causes of poor vision were diagnosed and referred for treatment. The results of these interventions were collected (examination 2) and analysed by Chi-square test. RESULTS: At examination 1 in project A, 47 of 62 patients (75.6%) had visual acuity < or = 20/100. The main causes of poor vision were refractive error (31.9%) and posterior capsule opacification (17.0%), with or without refractive error. At examination 1 in project B, 22 of 34 patients (64.7%) had visual acuity < or = 20/100. The main causes of poor vision were again posterior capsule opacification (50.0%) and refractive error (9.0%). After posterior capsulotomy with Nd:YAG laser and prescription of new corrective eyeglasses, visual acuity = 20/80 was obtained in 64.5% of patients in project A (OR = 0.18, CI = 0.07-0.41) and 70.5% of patients in project B (OR = 0.19, CI = 0.06-0.60) at examination 2. The causes of blindness in the remaining patients were identified. CONCLUSION: This type of project is effective in reducing blindness caused by cataracts in developing countries. However, long-term scheduled follow-up of operated patients is an effective means of avoiding consecutive blindness resulting from secondary cataracts and refractive changes.

Aged↗

PubMed1999

Ocular predictors of the onset of juvenile myopia.

PURPOSE: The purpose of this study was to identify reliable predictors of the onset of juvenile myopia. METHODS: The data from 554 children enrolled in the Orinda Longitudinal Study of Myopia (OLSM) as nonmyopes with baseline data from the third grade were evaluated to develop a predictive profile for later onset of juvenile myopia. Myopia was defined as at least -0.75 D of myopia in the vertical and horizontal meridians of the right eye as measured by cycloplegic autorefraction (n = 45 children). Chosen predictors were refractive error and the ocular components: corneal power, Gullstrand crystalline lens power, and axial length. Sensitivity and specificity were calculated. Receiver operating characteristic (ROC) curves were generated to evaluate and compare these predictors singly and combined. RESULTS: Refractive error, axial length, Gullstrand lens and pod corneal power were all significant predictive factors for the onset of juvenile myopia. The best single predictor of future myopia onset in the right eye was the right eye's cycloplegic autorefraction spherical refractive error value (mean sphere across 10 readings) at baseline. For a cut point of less than +0.75 D hyperopia in the third grade, sensitivity was 86.7% and specificity was 73.3%. The area under the ROC curve for this mean sphere was 0.880. Producing a logistic model combining mean sphere, corneal power, Gullstrand lens power, and axial length results in a slight improvement in predictive ability (area under the ROC curve = 0.893). CONCLUSIONS: Onset of juvenile myopia can be predicted with moderate accuracy using the mean cycloplegic, spherical refractive error in the third grade. Measurement of other ocular components at this age improves predictive ability, albeit incrementally. Further improvements in the prediction of myopia onset will require the use of longitudinal data in addition to one-time measurement of refractive error and the ocular components.

Adolescent↗

PubMed2002

Phakic intraocular lenses and refractory lensectomy for myopia.

Phakic intraocular lens implantation (IOLs) and clear lens extraction for high to extreme myopia have grown in popularity recently as a consequence of potentially unsatisfactory results with corneal refractive surgery in higher ranges of refractive errors. The refractive outcome of these alternative modalities has been encouraging to date, yet the potential for significant complications exists. Current evidence shows that the risk of retinal detachment after clear lens extraction for myopes is high. Trials with angle-supported phakic IOLs revealed unacceptable rates of pupillary ovalization, IOL rotation, and endothelial cell loss. Iris-fixated and posterior chamber phakic IOLs have proven sufficient safety, but long-term follow-ups of current cohorts are still to be awaited. The implantation of either of the latter two phakic IOLs followed by laser in situ keratomileusis or photorefractive keratectomy (bioptics) provides another option in refractive surgery for high ametropia.

Anterior Chamber↗

PubMed1998

[Corneal topographic analysis after excimer laser photorefractive keratectomy].

OBJECTIVE: To analyze the changes in corneal topography after excimer laser photorefractive keratectomy (PRK). METHODS: The topographic changes of 122 eyes (62 patients) and 96 eyes (49 patients) on which PRK was performed were reviewed after 3 and 6 months of follow-up respectively. RESULTS: The central island pattern had a relationship with the loss of best corrected visual acuity of more than one line in early postoperative period. On subsequent follow-up, the central island pattern tended to become to other patterns (semicircular, keyhole and uniform) and the central corneal power decreased, allowing the visual acuity to improve gradually. The simulated K (Sim K) regression index was a useful indication of the changes in the corneal stroma. Sim K was related to the degree of refractive error. The greater the refractive error, the lower the Sim K. CONCLUSION: Corneal topography is a useful tool in the analysis of corneal changes in PRK.

Corneal Topography↗

PubMed2002

[History of excimer laser refractive surgery in Poland].

First publication about excimer laser in 1983 became the beginning of laser refractive surgery. At the beginning excimer laser was used for PRK procedure for correction of myopia. Laser refractive surgery developed rapidly in 90-ties when LASIK and LASEK procedures started to be used for any kind of refractive errors. In Poland laser refractive surgery begun to be used in 1990.

History, 20th Century↗

PubMed1991

A nation-wide study of myopia prevalence in Israel. Findings in a population of 312,149 young adults.

We conducted a nation-wide survey of the Prevalences of Myopia and other refractive errors in Israel, from data of medical examinations of an unselected population of 312,149 subjects ages 17 to 19 years. 80.47% of the population were emmetropic in both eyes. Myopia in both eyes was found in 16.27% of the population. The prevalence of monocular myopia was 1.69%. Manifest hyperopia in both eyes was found in 0.93% and astigmatism at least in one eye was found in 7.13%. The various errors of refraction (myopia, hyperopia and astigmatism) were more common among females.

Adolescent↗

PubMed1993

Prevalence of retinopathy in a Sri Lankan diabetes clinic.

OBJECTIVE: To determine the prevalence of diabetic retinopathy among patients with non-insulin dependent diabetes (NIDDM) attending a Sri Lankan diabetes clinic and assess the skills of non-ophthalmologist in screening for retinal disease. RESEARCH DESIGN AND METHOD: One thousand and three consecutive diabetic patients were screened for diabetic eye disease using a standardised technique based on the WHO Multinational Study. RESULTS: 31.3% (95% confidence intervals 28.0% to 31.6%) had retinopathy, 23% (95% confidence intervals 21% to 25%) had cataract and 20% (95% confidence intervals 17% to 23%) had previously undetected refraction errors. 4.1% (95% confidence intervals 2.1% to 6.0%) of patients were blind due to advanced retinal disease while 6.2% (95% confidence intervals 5.0% to 7.2%) were blind as a result of cataract. General physicians had a 90.6% sensitivity and 100% specificity in screening for retinal disease. CONCLUSIONS: Retinopathy accounts for significant visual handicap. Untreated cataract is more commonly associated with blindness. Undiagnosed errors of refraction account for significant visual handicap in Sri Lankan diabetic patients. Physicians trained in techniques of retinal screening can correctly assess diabetic retinal changes in a high proportion of patients.

Clinical Competence↗

PubMed2003

Intraocular lens power calculation formulas in Chinese eyes with high axial myopia.

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation formulas in Chinese eyes with high axial myopia. SETTINGS: Department of Ophthalmology, Tuen Mun Hospital, Hong Kong, China. METHODS: This retrospective study reviewed 125 Chinese patients with high myopia and axial lengths (ALs) longer than 25.0 mm who had cataract surgery during the year 2000. Eyes with pathology or operative complications affecting the refractive status and those with missing data were excluded. In each case, the power of the implanted IOL was used to calculate the predicted postoperative refractive error by 4 IOL power calculation formulas: SRK II, SRK/T, Holladay 1, and Hoffer Q. The predictive accuracy of the formulas was analyzed by comparing the difference between the "actual" and "predicted" postoperative refractive errors. The Student t test was used for statistical analysis. The performance of the formulas in subcategories of long AL was also tested. RESULTS: One hundred twenty-five eyes (110 patients) were studied. Thirty-seven eyes (29.6%) were excluded. The Hoffer Q, Holladay 1, and SRK/T formulas showed a slight tendency toward resultant hyperopia, with a mean of +0.36 diopters (D), +0.53 D, and +0.74 D, respectively. The SRK II caused the largest hyperopic error, with a mean of +1.47 D. All 4 formulas caused a refractive error shift toward myopia in the subcategories of AL >28.0 mm, minus-power IOL, and extracapsular cataract extraction (ECCE). CONCLUSIONS: In Chinese eyes with high axial myopia with an AL longer than 25.0 mm, the 4 formulas caused a slight postoperative hyperopic refractive error that was less in eyes with a minus-power IOL or an AL longer than 28.0 mm and in those that had ECCE. The Hoffer Q formula provided the best predictive result, and Holladay 1 and SRK/T were comparable in IOL power calculation. The SRK II was the least accurate in all subgroups.

Adult↗

PubMed1995

Spectacle lenses alter eye growth and the refractive status of young monkeys.

The influence of visual experience on ocular development in higher primates is not well understood. To investigate the possible role of defocus in regulating ocular growth, spectacle lenses were used to optically simulate refractive anomalies in young monkeys (for example, myopia or nearsightedness). Both positive and negative lenses produced compensating ocular growth that reduced the lens-induced refractive errors and, at least for low lens powers, minimized any refractive-error differences between the two eyes. These results indicate that the developing primate visual system can detect the presence of refractive anomalies and alter each eye's growth to eliminate these refractive errors. Moreover, these results support the hypothesis that spectacle lenses can alter eye development in young children.

Accommodation, Ocular↗

PubMed2003

Five-year refractive changes in an older population: the Blue Mountains Eye Study.

PURPOSE: To examine 5-year changes in refractive error and astigmatism in an older population. DESIGN: Population-based cohort study. PARTICIPANTS: The Blue Mountains Eye Study examined 3654 residents aged 49 years or older from 1992 to 1994. After excluding 543 persons who died since baseline, 2335 (75.1%) attended 5-year examinations from 1997 to 1999. METHODS: Both examinations included a detailed eye assessment, with subjective refraction performed according to a modified Early Treatment of Diabetic Retinopathy Study protocol. MAIN OUTCOME MEASURES: Spherical equivalent (sum of sphere + cylinder) was used as the measure of refractive error. Only phakic eyes with best-corrected visual acuity >20/40 were included (n = 3701). RESULTS: Similar changes in refractive error were observed for the two eyes. Symmetric changes were found in 72% of participants when the difference between eyes was within 0.5 diopters (D) and in 91% when the difference was within 1.0 D. The 5-year change in spherical power was in a hyperopic direction for younger age groups and in a myopic direction for older subjects, P < 0.0001. The gender-adjusted mean change in refractive error in right eyes of persons aged 49 to 54, 55 to 64, 65 to 74, and 75 years or older at baseline was +0.41 D, +0.30 D, +0.05 D, and -0.22D, respectively. Refractive change was strongly related to baseline nuclear cataract severity; grades 4 to 5 were associated with a myopic shift (-0.33 D, P < 0.0001). Education level and age of onset of myopia, but not gender or diabetes, also predicted refractive change. The mean age-adjusted change in refraction was +0.14 D for hyperopic eyes, +0.32 D for emmetropic eyes, and +0.15 D for myopic eyes. The mean change in cylinder power over the 5-year period was small, irrespective of baseline refraction. The axis of astigmatism remained stable in most cases (64%), whereas 12% changed to "against the rule" and 11% to "with the rule." CONCLUSIONS: This report has documented refractive error changes in an older population and confirmed reported trends of a hyperopic shift before age 65 years and a myopic shift thereafter associated with the development of nuclear cataract.

Age Distribution↗

PubMed1999

Comparative corneal topography and refractive variables in monozygotic and dizygotic twins.

PURPOSE: To investigate the role of heredity in determining corneal shape, axial length, and overall refractive error. METHODS: Twenty monozygotic and 19 dizygotic twin pairs, age 12 to 73 years, were enrolled in the study. Zygosity was determined by physical similarity and by responses to questions adapted from surveys. Two twin pairs were excluded because of undetermined zygosity and one pair because of keratoconus (both siblings). Refractive error was determined by an automated refractor. Manifest refraction was also recorded, as well as cycloplegic refraction in subjects under age 18 years. Corneal topography data and manual keratometer readings were also obtained. Axial lengths were determined by A-scan ultrasound. Data were analyzed by Student t tests only in the right eye. Left-eye data were comparable for all variables. RESULTS: Mean intrapair difference in refractive error (spherical equivalent) was less for monozygotic than for dizygotic twins (RE: 0.41 vs 1.53; P = .001). Mean intrapair difference in axial length was less for monozygotic twins (RE: 0.39 vs 0.76 mm; P = .031). Corneal topography data (power and meridian) in all zones (3, 5, and 7 mm) also showed smaller mean differences among monozygotic pairs than dizygotic, but the difference was statistically significant only for the 5-mm zone. In addition, most Holladay Diagnostic Summary variables that were studied did not show any statistically significant differences. CONCLUSIONS: Axial length and overall refractive error have a significant genetic basis. Corneal topography data appear to have other overriding determining factors for several of the variables studied.

Adolescent↗

PubMed2006

Simultaneous versus sequential penetrating keratoplasty and cataract surgery.

PURPOSE: To compare the surgical outcomes of simultaneous penetrating keratoplasty and cataract surgery with those of sequential surgery. METHODS: Thirty-nine eyes of 39 patients scheduled for simultaneous keratoplasty and cataract surgery and 23 eyes of 23 patients scheduled for sequential keratoplasty and secondary phacoemulsification surgery were recruited. Refractive error, regular and irregular corneal astigmatism determined by Fourier analysis, and endothelial cell loss were studied at 1 week and 3, 6, and 12 months after combined surgery in the simultaneous surgery group or after subsequent phacoemulsification surgery in the sequential surgery group. RESULTS: At 3 and more months after surgery, mean refractive error was significantly greater in the simultaneous surgery group than in the sequential surgery group, although no difference was seen at 1 week. The refractive error at 12 months was within 2 D of that targeted in 15 eyes (39%) in the simultaneous surgery group and within 2 D in 16 eyes (70%) in the sequential surgery group; the incidence was significantly greater in the sequential group (P = 0.0344). The regular and irregular astigmatism was not significantly different between the groups at 3 and more months after surgery. No significant difference was also found in the percentage of endothelial cell loss between the groups. CONCLUSION: Although corneal astigmatism and endothelial cell loss were not different, refractive error from target refraction was greater after simultaneous keratoplasty and cataract surgery than after sequential surgery, indicating a better outcome after sequential surgery than after simultaneous surgery.

Aged↗

PubMed2006

Modelling the normal retinal nerve fibre layer thickness as measured by Stratus optical coherence tomography.

BACKGROUND: The variation in retinal nerve fibre layer thickness (RNFLT) as measured by Stratus optical coherence tomography (OCT) in healthy subjects may be reduced when the effect on RNFLT measurements of factors other than disease is corrected for, and this may improve the diagnostic accuracy in glaucoma. With this perspective we evaluated the isolated and combined effects of factors potentially affecting the Stratus OCT RNFLT measurements in healthy subjects. METHODS: We included 178 healthy eyes of 178 subjects between 20 and 80 years of age. Participants underwent an extensive eye examination. Stratus OCT RNFLT was measured by three standard protocols, two with high and one with standard image resolution. Effects on RNFLT of age, gender, refractive error, axial length, lens nuclear colour and opalescence, intra-ocular pressure (IOP), and optic disc size were examined by univariate and multivariate analyses. RESULTS: Age, refractive error, axial length, and lens nuclear colour and opalescence affected RNFLT in univariate analyses, whereas gender, IOP, and optic disc size had no significant effect. In multivariate analyses only age in combination with refractive error, or with axial length, was significant and explained 14.7-17.6% (R2) of the total variation of RNFLT, approximately 50% more than age alone. RNFLT decreased by 2.6-2.9 microm per increasing decade of age and increased by 1.5-1.8 microm per more positive diopter of spherical equivalent using full-circle measurements of the three standard protocols. These effects varied between measurement sectors. CONCLUSIONS: RNFLT as measured by Stratus OCT standard protocols was significantly affected by age and refractive status. The effect on global RNFLT of a difference in refractive error of 10 diopters corresponded to the effect of a difference in age of 60 years. Theoretically, the effect of refractive status may be explained by artefacts of RNFLT measurement circle placement. The results suggest that the diagnostic accuracy of Stratus OCT may be improved by considering refractive status in addition to age when RNFLT is measured. For this purpose spherical equivalent seems as effective as axial length.

Adult↗

PubMed2004

A survey of clinical prescribing philosophies for hyperopia.

BACKGROUND: Prescribing philosophies for hyperopic refractive error in symptom-free children vary widely because relatively little information is available regarding the natural history of hyperopic refractive error in children and because accommodation and binocular function closely related to hyperopic refractive error vary widely among children. We surveyed pediatric optometrists and ophthalmologists to evaluate typical prescribing philosophies for hyperopia. METHODS: Practitioners were selected from the American Academy of Optometry Binocular Vision, Perception, and Pediatric Optometry Section; the College of Vision Development; the pediatric and binocular vision faculty members of the colleges of optometry; and the American Association for Pediatric Ophthalmology and Strabismus. Surveys were mailed to 314 participants: 212 optometrists and 102 ophthalmologists. RESULTS: A total of 161 (75%) of the optometrists and 59 (57%) of the ophthalmologists responded. About one-third of optometrists surveyed prescribe optical correction for symptom-free 6-month-old infants with +3.00 D to +4.00 D hyperopia, but fewer than 5% of ophthalmologists prescribe at this level. Most eye care practitioners prescribe optical correction for symptom-free 2-year-old children with +5.00 D of hyperopia, and this criterion for hyperopia decreases with age. Most ophthalmologists (71.4%) prescribe the full amount of astigmatism and less than the full amount of cycloplegic spherical component, and most optometrists (71.6%) prescribe less than the full amount of both components. When prescribing less than the full amount of astigmatism, eye care practitioners do not tend to prescribe a specific proportion of the cycloplegic refractive error. CONCLUSION: Pediatric eye care providers show a lack of consensus on prescribing philosophies for hyperopic children.

Data Collection↗

PubMedDate not supplied

Expanded range customcornea algorithms for myopia and astigmatism: one-month results.

PURPOSE: To evaluate the early clinical results achieved with an algorithm adjusted for an expanded range of correction in wavefront-guided customized ablation with the LADARVision4000 (Alcon Laboratories Inc, Fort Worth, Tex). METHODS: Fifty-five consecutive eyes from 31 patients underwent wavefront-guided, customablation laser in situ keratomileusis (LASIK) (Hansatome and BD 4000 microkeratomes, LADARWave aberrometer, LADARVision4000 laser system). These were normal myopic and astigmatic eyes that had never been operated on. The spherical equivalent refractive error was +0.30 to -8.13 diopters (D) (mean -4.26 +/- 2.14 D) and the astigmatism ranged from 0 to -3.75 D (mean -0.97 +/- 0.96 D). eyes were treated according to the CustomCornea protocol using the commercial LADARVision4000 platform. Patients were followed for at least 2 months and standard visual measurements were taken and recorded at 1 day and 1, 3, and 6 months after treatment. The results of treatment were assessed using the following parameters: uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA); manifest spherical equivalent refractive error; wavefront measurement of high order aberrations; and subjective reports of visual symptoms by patients. RESULTS: One month after LASIK, the mean manifest spherical equivalent refractive error was -0.18 +/- 0.41 D. Seventy-eight percent and 96% of eyes had manifest spherical equivalent refractive error within +/-0.50 D and +/-1.00 D of attempted correction, respectively, with 78% of eyes with 20/20 or better UCVA. Eyes with 20/16 and 20/12.5 BSCVA were 89% and 36%, respectively (55% and 7% preoperatively). The mean high order aberrations root-mean-square was 0.34 +/- 0.10 microm preoperatively and 0.35 +/- 0.09 microm postoperatively (6.0-mm pupil size). High order aberrations were either reduced, unchanged, or increased by <10% in 58% of eyes. Subjectively, patients reported no visual symptoms and had no complaints regarding the quality of their vision. CONCLUSION: The new optimized algorithm for higher refractive errors appears to be effective in improving BSCVA, and a minority of patients demonstrated an increase in the magnitude of high order aberrations when compared to preoperative aberrometry. A slight spherical equivalent refraction undercorrection will be addressed with future nomogram adjustments.

Adult↗