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PubMed1994

A comparison of drop instillation and spray application of 1% cyclopentolate hydrochloride.

We compared the objective cycloplegic refractive error of 37 hyperopic children (ages 18 months to 6 years). Cycloplegia was by spray application to the closed eye, or by a one-drop instillation to the open eye. Patients were initially screened for hyperopia using a masked noncycloplegic retinoscopy with loose trial lenses. Spray and drop cycloplegias (1% cyclopentolate hydrochloride; 1% Spectro Pentolate) were administered to each patient in random order within a 2-week period. A masked cycloplegic retinoscopy was performed 20 min after drug administration for patients with "light" iris coloration and after 40 min for those with "dark" irides. One examiner conducted all cyclopentolate administrations; a separate examiner (masked to application method) conducted all refractive testing. For right eyes, the mean spherical equivalent refractive error after spray application was 1.76 D (SD = 1.63 D) and after drop instillation 1.78 D (SD = 1.85 D). Results were similar for the left eyes. These small differences were not statistically significant (ANOVA, F = 0.05, p = 0.82). The absolute difference in spherical equivalent was 0.50 D or less in 93% of all subject eyes. A scaling system was used to rate the ease of administration and the patient's response to each method. Using an exact test of marginal homogeneity, the response rating for the spray method was significantly better (p = 0.038). The spray application of cyclopentolate hydrochloride is easier to administer and is an effective alternative to traditional drop instillation.

Child↗
PubMed2004

Non-cycloplegic refractive screening can identify infants whose visual outcome at 4 years is improved by spectacle correction.

The Second Cambridge Population Infant Vision Screening Programme using the VPR-1 videorefractor without cycloplegia was undertaken in order to identify those infants with refractive errors who were potentially amblyogenic or strabismogenic. Infants identified at eight months were entered into a control trial of treatment with partial spectacle correction and underwent a long-term follow-up that monitored a wide range of visual, visuoperceptual, visuocognitive, visuomotor, linguistic and social development. In the present paper, the authors report on the outcome measures of visual acuity and strabismus. Poor acuity was defined as a best-corrected acuity of 6/12 or worse on crowded letters or 6/9 or worse on single letters, at age 4 years. Acuity was measured in 79 infants who were significantly hyperopic and/or anisometropic at 11-12 months of age, 23 who showed hyperopia of +3D but less than +3.5D, 196 control subjects, 14 controls with refractive errors, and 126 others who showed an accommodative lag on screening but were not significantly hyperopic on first retinoscopy. There was a poorer acuity outcome in the untreated group of hyperopes compared to controls (p < 0.0001) and to the children who were compliant in spectacle wear (p < 0.001) or who were prescribed spectacles (p < 0.05). Children who were significantly hyperopic at eight months were also more likely to be strabismic by 5.5 years compared to the emmetropic control group (p < 0.001). However, the present study did not find a significant difference in the incidence of strabismus between corrected and uncorrected hyperopic infants. Children who were not refractively corrected for significant hyperopia were four times more likely to have poor acuity at 5.5 years than infants who wore their hyperopic correction, supporting the findings of the First Cambridge Population Infant Vision Screening Programme.

Accommodation, Ocular↗
PubMed1987

Repeated radial keratotomy in the prospective evaluation of radial keratotomy study.

In the Prospective Evaluation of Radial Keratotomy study, 59 patients received a repeated radial keratotomy in which the eight additional incisions were centered between the eight initial incisions. Other aspects of the surgical technique remained the same. The average length of follow-up after the reoperation was 26 months, and ranged from 11 to 42 months. After the reoperation, 45 patients (77%) had a decrease in myopia of 0.50 diopters or more, 12 patients (20%) changed by less than 0.50 diopters, and two patients (3%) had an increase in myopia. Thirty patients (51%) remained undercorrected by more than 1.00 diopter, 27 patients (46%) were between +0.12 and -1.00 diopter, and two patients (3%) were overcorrected by more than 1.00 diopter. There was no relationship between the change in refractive error after the reoperation and any patient characteristics or surgical factors. After the reoperation, the uncorrected visual acuity increased by two to nine Snellen lines for 45 patients (76%), changed one line or less for 13 patients (22%), and decreased three lines for one patient (2%).

Evaluation Studies as Topic↗
PubMed2006

Analysis of wavefront-guided corrections to see if they fully correct ocular aberrations.

In a recent paper [J. Opt. Soc. Am. A22, 1473 (2005)], the authors concluded, as a result of analysis using an optical model of the eye, that wavefront-guided ablative correction of the refractive errors of the eye does not efficiently remove those errors. An analytical method is given that analyzes the effect of a wavefront-guided ablative treatment of the aberrations of the eye using only the measured wavefront error of the eye and a measured or assumed anterior corneal surface shape and shows that in fact a wavefront-guided ablative treatment does remove all clinically significant error of the eye if only the anterior surface of the cornea is physically altered as planned as a result of treatment. The use of a variation of the method to analyze the effect of treatment when other changes occur as a result of treatment is also given.

Computer Simulation↗
PubMed2001

Management of the corneal flap in laser in situ keratomileusis after previous radial keratotomy.

PURPOSE: To report a method of managing the corneal flap in patients having laser in situ keratomileusis for the treatment of residual refractive errors after radial keratotomy. DESIGN: Retrospective case series. METHODS: Intraoperative dehiscence of radial keratotomy wounds occurred in 7 eyes of 6 patients treated with laser in situ keratomileusis for residual myopia or astigmatism or hyperopia 5 to 15 years after radial keratotomy. To minimize extension of these tears, the flap was initially rolled like a carpet toward the hinge before the ablation and then rolled away from the hinge to its original position after the ablation. RESULTS: Using this method of managing the laser in situ keratomileusis flap in patients with previous radial keratotomy, all eyes had successful laser in situ keratomileusis, with 1-year postoperative uncorrected visual acuity ranging between 20/16 and 20/25. No eye had loss of spectacle-corrected vision or interface epithelial ingrowth. CONCLUSIONS: Laser in situ keratomileusis has proved to be an effective treatment for correction of residual refractive errors after radial keratotomy. The surgical technique used in these cases was targeted at minimizing shearing forces in lifting the corneal flap to avoid extension of radial keratotomy wound dehiscence, which could lead to epithelial ingrowth and loss of best-corrected vision.

Adult↗
PubMed2004

Use of AcrySof acrylic foldable intraocular lens for secondary implantation in children.

PURPOSE: Secondary intraocular lens (IOL) implantation is an increasingly viable option in the management of pediatric aphakia. We report our experience of secondary IOL implantation in pediatric patients using the AcrySof (Alcon Surgical, Fort Worth, Texas) 3-piece foldable lenses through a small incision. METHODS: We reviewed the records of all our patients < 18 years undergoing secondary IOL implantation of the AcrySof lens from 1997 to 2001. All patients with a minimum of 6 months follow-up were included. Records were analyzed for age at surgery, postoperative acuity change, postoperative refractive error and anisometropia, surgical complications, and length of follow-up. RESULTS: Fifty-five eyes of 36 patients were included in the review. Mean age at surgery was 7.4 years (1.1 to 15.4), and mean follow-up was 28 months (6.3 months to 5 years). Vision decrease > 2 lines was noted in 3 eyes (5.8%) during the follow-up period. Complications included IOL decentration in 3 eyes (5%), wound leak in 3 eyes (5%), secondary membrane formation in 5 eyes (9%), pupillary block glaucoma in 1 eye (2%), and ptosis in 1 eye (2%). Four eyes (7%) required reoperation for complications. Mean postoperative refractive error was -0.1 +/- 3.2 diopters (D), and mean anisometropia was 2.01 +/- 1.44 D. Glaucoma subsequently developed in 6 eyes (11%), 2 of which required surgical correction. CONCLUSIONS: Secondary placement of the AcrySof IOL in the ciliary sulcus is a safe and effective method to correct aphakia in pediatric patients with adequate capsular support. The incidence of complications requiring reoperation is low.

Acrylates↗
PubMed2001

Refractive surgery in children.

Refractive surgery techniques, especially those using laser ablation, have revolutionized the treatment of refractive errors. The short-term results have been well studied in adults, but long-term outcomes are not known. No good studies exist to tell us whether the pediatric eye responds the same as the adult eye to these techniques, but there is reason to believe that the pediatric eye will have many differences, both short- and long-term based on other similar surgeries adapted for pediatrics. These techniques have great potential to add to our armamentarium of treatments for frustrating problems such as unilateral high myopia with amblyopia, but they should be used with caution. The patients who are the most attractive to refractive surgeons, namely, teenagers with typical myopia who want to discard their spectacles, are the patients with potentially the most to lose from a procedure with unknown long-term results for a condition easily treated with other modalities. Those who need it most, namely infants and children with high anisometropia who cannot tolerate contact lenses or spectacles, are the least cooperative, the most difficult to treat postoperatively, and the least able to afford expensive treatments not covered by insurance, are therefore the least likely to be offered the procedure, or to have a study designed to evaluate their specific needs and concerns. It behooves ophthalmologists interested in pediatrics to carefully discuss and research the possible indications and theoretical concerns of these powerful techniques in pediatric eyes.

Child↗
PubMed2003

[Applying deep lamellar keratoplasty in corneal disorders without endothelial abnormalities].

PURPOSE: To present own experiences in the surgery of deep lamellar keratoplasty. MATERIALS AND METHODS: 25 eye of 25 patients suffering from various corneal pathologies with preserved endothelium: 22 with keratoconus eyes, 2 with post-inflammatory scar and one eye with leucoma in Stevens-Johnson syndrome. Mean follow-up was 25.5 months (from 6 to 32). Main outcome measures were Non-Corrected and Best Corrected Visual Acuity (NCVA, BCVA), astigmatism, refractive error, IOP and corneal transparency. The surgery was performed in general anesthesia. In majority of cases the recipient stroma was trephined to a depth of 70% with 7.5 mm diameter vacuum trephine. In cases of intraoperative perforation of Descemet membrane with shallow anterior chamber we converted the procedure into penetrating keratoplasty. The donor lenticule was trephined in the artificial chamber with the 0.5 mm oversized manual trephine to a depth of 90%. In two cases after DLK was finished, limbal stem cell grafting was additionally performed. RESULTS: Postoperative NCVA ranged from 0.01 to 0.8 and BCVA from 0.1 to 0.8. Astigmatism ranged from 0.5 to 10.0 D. Refractive error ranged from -8.0 to +1.0 D. In follow-up period all grafts maintained transparent. The complications were mainly intraoperative perforations of Descemet membrane (9 cases): in 7 cases we convert the procedure into penetrating keratoplasty. In 2 cases the double chamber-forming was observed: in one case on 7 day following surgery the penetrating keratoplasty was performed, in other a spontaneous attachment was observed. We also observed loose sutures in 2 cases, inflammatory infiltrates in one case. Two cases of ocular hypertension was successfully treated by medication. CONCLUSIONS: Deep lamellar keratoplasty is an effective procedure for treating various diseases of corneal stroma with unaffected endothelium.

Adult↗
PubMedDate not supplied

Photorefractive keratectomy for hyperopia in 800 eyes with the Meditec MEL 60 laser.

PURPOSE: To evaluate the refractive results of 800 hyperopic eyes undergoing PRK treatment. METHODS: Eight hundred hyperopic eyes were treated with PRK. An Aesculap-Meditec MEL 60 scanning ArF excimer laser used. Treatment Group 1 consisted of eyes with a preoperative refractive error of +3.50 D or less (n = 482) and Group 2, of +3.75 D or more (n = 318). RESULTS: Preoperatively, Group 1 required an average correction of +2.88+/-1.34 D and Group 2 required +5.64+/-2.96 D. One year after PRK, average residual correction was +1.26+/-1.24 D in Group 1, and in Group 2, +2.46+/-1.84 D. In Group 1, uncorrected visual acuity (UCVA) was 20/40 or better in 88.4% (426/482); 20/20 or better in 75.7% (365); 2.1% (10/482) of eyes lost 2 lines, 2.1% (10/482) gained 2 lines; 3.1% (15/482) gained 2 or more lines of BSCVA; 74.4% (359/482) of eyes were within +/-0.50 D of target correction and 84.8% (408/482) were within +/-1.00 D. In Group 2, 47.5% (151/318) had UCVA of 20/40 or better; 34.2% (109/318) saw 20/20 or better uncorrected; 19.1% (61/318) lost 2 lines; 11.6% (37/318) lost 3 lines; none of the eyes gained 2 or more lines of BSCVA; 22.3% (71/318) were within +/-0.50 D and 46.8% (149/318) were within +/-1.00 D of target correction. Refractive stability was achieved after 6 months; a slight regression after 6 months was still observed. In Group 1, 10.5% (42/482) and in Group 2, 21.6% (69/318) complained of problems with daytime vision (glare and ghost image); during night-driving in Group 1, 17.6% (85/482) and in Group 2, 40.5% (129/318) had problems. CONCLUSION: PRK with the Aesculap-Meditec MEL 60 scanning ArF excimer laser offered the best long-term results with +3.50 D or less preoperative refractive error. With higher corrections, regression, decrease in BSCVA, and daytime visual problems were encountered.

Adult↗
PubMed2005

LASIK in patients with rheumatic diseases: a pilot study.

PURPOSE: To investigate the safety of LASIK in patients with a known history of controlled rheumatic diseases. DESIGN: Retrospective consecutive observational clinical study. PARTICIPANTS: Forty-two eyes (22 patients) known to have had a history of rheumatic diseases underwent LASIK. All patients had a history of controlled rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, scleroderma, ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease, arthritis, or Behçet's disease. METHODS: Assessments were made preoperatively and at 1, 3, and 6 months postoperatively and included visual acuity (VA), refraction, keratometric readings, slit-lamp biomicroscopy, and corneal topography. All the patients underwent LASIK. Postoperative treatment included a topical steroid-antibiotic combination. MAIN OUTCOME MEASURES: Visual acuity, refraction, keratometric readings, and slit-lamp biomicroscopy findings at 1, 3, and 6 months postoperatively. RESULTS: LASIK was performed uneventfully on all patients. The mean pre-LASIK spherical equivalent (SE) was -5.39+/-2.25, and the sixth month postoperative SE was -0.15+/-0.38 diopters (D) (P<0.001). Uncorrected VA 6 months after the LASIK procedure was 20/25. Enhancement procedures were performed in 6 of 42 eyes (14.3%) at variable times after the primary procedure. Postoperative follow-up showed development of a moderate degree of dry eye syndrome in 4 eyes (9.5%). Corneal haze, melting, flap, or interface complications were not observed in any of the study eyes. CONCLUSIONS: In this small series, we found good outcomes when correcting refractive errors using LASIK in selected patients with controlled rheumatic diseases. In this series, a favorable postoperative visual outcome was obtained with no operative or postoperative vision-threatening complications.

Adult↗
PubMed1996

Optic disc shape in glaucoma.

BACKGROUND: This study was performed to evaluate the shape of the optic disc in glaucoma. METHODS: We examined morphometrically color stereo optic disc photographs of patients with primary open-angle glaucoma (n = 804), secondary open-angle glaucoma (n = 130), normal-pressure glaucoma (n = 75), and high myopia combined with open-angle glaucoma (n = 33), visually normal subjects (n = 421), and nonglaucomatous subjects with high myopia (n = 36). The optic disc form was determined by the ratio of the minimal to the maximal disc diameter, the ratio of the horizontal to the vertical disc diameter, the angle between the maximal disc diameter and the horizontal, and a calculated form factor. RESULTS: In the normal eyes, the ratios and the form factor varied interindividually by less than 1:2. For a myopic refractive error of less than -8 D, the normal eyes and the glaucoma eyes did not differ significantly (P > 0.20) in their slightly vertically oval optic disc shape. Within the primary open-angle glaucoma group, the optic disc shape was not correlated with the neuroretinal rim area and the mean perimetric defect, either interindividually or in an intraindividual bilateral comparison. In the highly myopic group, the optic disc was significantly more ovally configurated, more obliquely orientated, and larger than in any other group. CONCLUSIONS: In contrast to the size of the optic nerve head, the shape of the optic disc does not show pronounced interindividual variability in eyes with a myopic refractive error of less than -8 D. With highly myopic eyes excluded, the optic disc shape as single variable is not markedly important for pathogenesis, early diagnosis and differential diagnosis of the glaucomas.

Diagnosis, Differential↗
PubMed2005

Amblyopia: prevalence, natural history, functional effects and treatment.

Amblyopia, defined as poor vision due to abnormal visual experience early in life, affects approximately three per cent of the population and carries a projected lifetime risk of visual loss of at least 1.2 per cent. The presence of amblyopia or its risk factors, mainly strabismus or refractive error, have been primary conditions targeted in childhood vision screenings. Continued support for such screenings requires evidence-based understanding of the prevalence and natural history of amblyopia and its predisposing conditions, and proof that treatment is effective in the long term with minimal negative impact on the patient and family. This review summarises recent research relevant to the clinical understanding of amblyopia, including prevalence data, risk factors, the functional impact of amblyopia and optimum treatment regimes and their justification from a vision and life skills perspective. Collectively, these studies indicate that treatment for amblyopia is effective in reducing the overall prevalence and severity of visual loss from amblyopia. Correction of refractive error alone has been shown to significantly reduce amblyopia and less frequent occlusion can be just as effective as more extensive occlusion. Occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life, and these factors should be considered in prescribing treatment, particularly because of their influence on compliance. Ongoing treatment trials are being undertaken to determine both the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion. This review highlights the expansion of current knowledge regarding amblyopia and its treatment to help clinicians provide the best level of care for their amblyopic patients that current knowledge allows.

Adaptation, Psychological↗
PubMed2004

Update on laser subepithelial keratectomy (LASEK).

PURPOSE OF REVIEW: This study reviews current concepts in laser subepithelial keratectomy (LASEK), variations in LASEK techniques, the role of pharmacology in LASEK, and optimizing outcomes in LASEK. RECENT FINDINGS: Recent studies continue to support the use of LASEK over that of LASIK in the correction of refractive error. In addition, the advent of pharmacological/biologic intervention, improved algorithms, and wavefront technology have expanded the armamentarium available to ophthalmologists in the maximization of LASEK outcomes. SUMMARY: LASEK offers an excellent profile in terms of both final outcome (uncorrected visual acuity) and safety (best corrected visual acuity). Untoward effects of LASEK are readily prevented/treated with a variety of agents. Postoperative pain can be ameliorated using topical and oral analgesia. Infection can be most effectively addressed with the fourth generation of fluoroquinolones. Haze may be treated or prevented using numerous remedies namely autologous serum, steroids, ascorbic acid, mitomycin-c, and NSAIDS. Wavefront combined with LASEK rather than with LASIK may offer the best refractive outcome.

Humans↗
PubMed2004

Temporal variation in diabetic macular edema measured by optical coherence tomography.

PURPOSE: To determine, by optical coherence tomography (OCT), whether there is a quantitative decrease in macular edema in diabetic subjects over the course of a day. STUDY DESIGN: Observational case series. PARTICIPANTS: Ten subjects with diabetic macular edema in 1 or both eyes. METHODS: Subjects were admitted to the hospital the evening before the study so that they would remain in the recumbent position until immediately before study measurements began. They then underwent 4 OCT measurements of macular thickness in both eyes, at 8:00 am, 11:00 am, 2:00 pm, and 5:00 pm. At each of these times, they also had refractions and visual acuity measurements using the Early Treatment Diabetic Retinopathy Study protocol. Macular thickness measurements determined by the Zeiss-Humphrey (Dublin, CA) optical coherence tomograph for each eye of each subject were plotted as a function of time. MAIN OUTCOME MEASURES: Temporal changes in retinal thickness in each of the 9 macular sectors defined by the OCT protocol and in the entire macula of each eye, averaged from all 9 sectors; temporal changes in refractive error and visual acuity. RESULTS: Four of the 10 subjects showed consistent decreases in macular thickness over the course of the day in 1 or more of the retinal sectors in 1 or both eyes. When macular thickness values were averaged over all 9 sectors for all subjects, both eyes showed consistent declines in mean thickness throughout the day. By t test, the 8 am value in each eye was significantly higher (P<0.0005) than any of the 3 later values, which did not differ significantly from each other. However, comparison of all 4 values by analysis of variance showed no significant differences. With the exception of 1 subject, there were no consistent changes in refractive error or in best-corrected visual acuity over the course of the study. CONCLUSIONS: This study, using quantitative OCT determinations, seems to confirm the much earlier report by Sternberg et al, which used more subjective methods, that macular edema might vary over the day. That the 8 am value, obtained just after waking, was higher than the 3 later values (highly significant by 1 test) suggests that the decrease in macular thickness is most likely due to the shift from recumbent to upright body position, although our study protocol did not exclude other possible mechanisms. Although changes in macular thickness over the course of the day did not occur in all subjects, therapeutic studies for macular edema that use OCT as an outcome measure should control for time of day when these measurements are carried out.

Aged↗
PubMed2002

Bilateral ametropic functional amblyopia in genetic ectopia lentis: its relation to the amount of subluxation, an indicator for early surgical management.

To determine the visual results of conservative (non- surgical) therapy, we reviewed all our patients with genetic ectopia lentis, with and without Marfan's Syndrome. Of these patients, 50% had significant permanent (or potentially so) ametropic functional amblyopia (visual acuity 20/50 to 20/200) in spite of good conservative management. This was especially true (100%) if the amount of lens dislocation was such that the lens edge was approaching the center of the pupil (vision still primarily phakic). The worst amblyopia was noted when the lens was still covering the visual axis and the lens edge was 1.3 mm from the center of the pupil (range of 0.3 to 2.3 mm). With regard to the most serious complication of ectopia lentis and its treatment, retinal detachment, when it occurred in our patients it was more strongly related to axial high myopia than surgery, per se. Since the axial high myopia which characteristically develops in ectopia lentis is probably the result of the amblyopia or the amblyopiagenic optics of ectopia lentis, lentectomy may be indicated early in this condition, before the axial high myopia develops, to prevent both axial high myopia and the attendant risks of retinal detachment as well as functional amblyopia. If the refractive error cannot be corrected well and the resultant ametropic amblyopia does not respond to conservative management, early surgery should be considered. If the lens is subluxated so that the edge of the lens approaches to within 0.3 to 2.3 mm of the center of the pupil (with best correctable vision still phakic), this is highly probable.

Adolescent↗
PubMed2003

Development of a repeatedly adjustable intraocular lens.

PURPOSE: To provide a variable-focus intraocular lens (IOL) that is able to adjust repeatedly and reversibly. SETTING: University of Missouri-Rolla, Rolla, and Eggleston Adjustable Lens, St. Louis, Missouri, USA. METHODS: An adjustable IOL based on a mechanically adjustable design has been developed. Prototypes were fabricated from traditional Perspex CQ poly(methyl methacrylate) (PMMA) provided off the shelf by a current IOL manufacturer. The prototypes have undergone proof-of-concept testing per the requirements of National Institutes of Health grant 1 R41 EY13482-01, with specific attention to the feasibility and safety of continuing development of the lens with in vivo trials. The experimental results presented focus on operational force measurements. RESULTS: Prototype lenses were produced consistently. Operational force measurements indicated that use of the mechanical adjustment mechanism is viable for an adjustable IOL and provides repeated adjustments over time. Turning forces exhibited by the prototypes were low enough to suggest that operation of this adjustable IOL will not damage the capsular bag or ciliary body of the eye, a potential concern in using this design. Biocompatibility and optical quality of the prototype lenses are ensured by use of traditional Perspex CQ PMMA. CONCLUSIONS: The mechanically adjustable IOL provides a feasible and promising means of confronting postoperative refractive errors and the changing desires of patients. The viability of this IOL design has been proven, and results suggest that operation of the lens is safe enough to pursue in vivo trials. Evaluation of the biocompatibility of the lens architecture as well as the ultimate goal of noninvasive adjustment using this model are reported in a companion article.

Biocompatible Materials↗
PubMed1995

Penetrating keratoplasty after radial keratotomy. A report of six patients.

BACKGROUND: For more than 15 years, radial keratotomy has increased in popularity as an option for treating myopia in the United States. During this period of time, the procedure has been modified to improve results and decrease complications. Despite these changes, complications from radial keratotomy continue to occur. The authors report six cases of penetrating keratoplasty performed to correct significant loss of vision resulting from complications of radial keratotomy. METHODS: The surgical records of one author (WR) were reviewed retrospectively for penetrating keratoplasties performed for complications of radial keratotomy. RESULTS: Six cases of penetrating keratoplasty performed for complications of radial keratotomy were found. Severe loss of vision was the indication for surgery in each case, and was associated with aggressive and repeated incisional refractive attempts to correct astigmatism, hyperopic overcorrection, residual myopia, or refractive errors associated with keratoconus. Glare associated with subepithelial scarring and irregular astigmatism were the primary findings associated with loss of vision. CONCLUSIONS: Despite advances in technique and instrumentation, radial keratotomy is limited in the amount of myopia it can correct. The risk for loss of vision increases with increasing number of incisions, intersecting incisions, very small optical zones, and keratoconus.

Adult↗
PubMedDate not supplied

Factors influencing the need for enhancement after laser in situ keratomileusis.

PURPOSE: To confirm that enhancements after primary laser in situ keratomileusis (LASIK) are effective in dealing with residual refractive errors, and to determine if any variables prior to or during the primary LASIK procedure predisposed eyes to require subsequent enhancement. METHODS: A retrospective study of eyes undergoing primary LASIK with the VISX S2 or S3 laser and Hansatome microkeratome between January 1, 2000 and January 1, 2002 was done. Of the 393 eyes of 207 patients, 58 eyes (14%) underwent enhancement within a 16-month window of the primary procedure. Statistical comparisons were made between enhanced (n = 37) and non-enhanced (n = 148) patients, and enhanced (n = 48) and non-enhanced (n = 303) eyes, treated for myopia only. RESULTS: In comparing the primary LASIK parameters of enhanced to non-enhanced eyes in myopic patients, no significant difference was found in right vs left eye, season of the primary treatment, preoperative astigmatism, pachymetry, or amount of attempted astigmatism correction. A multivariate logistic regression analysis revealed that male gender, patient age over 45 years, and a history of recent rigid contact lens use within 6 months of primary LASIK were significantly associated with the need for enhancement. CONCLUSION: Enhancements were an effective way of dealing with residual refractive errors after primary LASIK. Age greater than 45 years or a history of recent rigid contact lens use were significantly associated with the need for enhancement in patients with myopia or myopic astigmatism.

Adult↗