Reduction of hyperopia associated with manual excision of Salzmann's nodular degeneration.

PURPOSE: Removing central corneal pathology often leads to a hyperopic shift secondary to corneal flattening. A myopic shift, or reduction in hyperopia, would be expected after removal of peripheral corneal pathology with central corneal steepening. This case illustrates the refractive changes induced by Salzmann's nodular degeneration and the myopic shift associated with their excision. METHODS: A 53-year-old female presented with a slowly progressive increase in hyperopia. Vision in the right eye was 20/40 with a refraction of +10.00 -4.00 x 90 degrees. Vision in the left eye was 20/30 with a refraction of +5.75 -2.00 x 105 degrees. Both corneas exhibited nodular subepithelial opacities in the mid-periphery. A superficial keratectomy was performed on each eye, 1 year apart. RESULTS: Twelve days postoperatively, uncorrected visual acuity in the right eye was 20/25, and 20/20 with a refraction of -0.75 -0.50 x 31 degrees, 6 months later. Six days postoperatively, uncorrected visual acuity in the left eye was 20/40, and 20/30 with a refraction of -1.25 D, 1 month later. CONCLUSION: Superficial keratectomy provides a means of restoring the original corneal contour, especially when the pathology is easily dissected from Bowman's layer. The surgeon should investigate the refractive status prior to the development of the nodules and be aware of the possible refractive change upon removal of the pathology.

Survey of patients with granular, lattice, avellino, and Reis-Bücklers corneal dystrophies for mutations in the BIGH3 and gelsolin genes.

OBJECTIVES: To search for novel mutations that cause corneal stromal dystrophies and to confirm or revise the clinical diagnosis of patients with these mutations. PATIENTS: Through review of the records of the Cogan Eye Pathology Laboratory at the Massachusetts Eye and Ear Infirmary, Boston, and of clinical records, we ascertained 14 unrelated patients with the clinical or histopathologic diagnosis of granular (3 cases), Avellino (5 cases), lattice (5 cases), or Reis-Bücklers (1 case) corneal dystrophy. METHODS: Clinical records and histopathologic findings of the index patients and their relatives were reviewed. Patients and selected relatives donated a blood sample from which leukocyte DNA was purified and assayed for mutations in the BIGH3 gene and, in 2 patients, the gelsolin gene, using the polymerase chain reaction and direct genomic sequencing. RESULTS: All index patients with the diagnosis of granular dystrophy or Avellino dystrophy had the missense mutation Arg555Trp or Arg124His, respectively, previously reported in the BIGH3 gene. Of the 5 index patients with a prior diagnosis of lattice dystrophy, 2 had the originally reported lattice mutation (Arg124Cys) in the BIGH3 gene, 1 had a more recently reported missense mutation (His626Arg) in the same gene, 1 had the missense mutation Asp187Asn in the gelsolin gene, and 1 had no detected mutation in either gene. Affected members of the family with Reis-Bücklers dystrophy did not carry the previously reported mutations Arg555Gln or Arg124Leu but instead carried a novel missense mutation Gly623Asp in the BIGH3 gene. CONCLUSIONS: Molecular genetic analysis can improve the accuracy of diagnosis of patients with corneal dystrophies. Two patients with a prior diagnosis of lattice corneal dystrophy had their diagnosis changed to gelsolin-related amyloidosis (1 case) or secondary, nonhereditary localized amyloidosis (1 case). A novel mutation in the BIGH3 gene that causes Reis-Bücklers dystrophy was uncovered through this analysis, and another recently reported novel mutation was encountered. These findings serve to expand our knowledge of the spectrum of pathogenic mutations in BIGH3.

Cataract extraction with multifocal intraocular lens implantation: a multinational clinical trial evaluating clinical, functional, and quality-of-life outcomes.

OBJECTIVE: Two million cataract extractions are performed annually in the United States. The procedure is nearly always accompanied by implantation of a monofocal intraocular lens (IOL), which corrects the patient's distance vision. The authors' objective was to measure visual function and quality-of-life outcomes associated with bilateral implantation of a multifocal IOL, which corrects distance and near vision, and to compare the outcomes with those of the standard therapy. DESIGN: A prospective, randomized, double-masked, clinical trial was conducted at eight sites in the United States, seven sites in Germany, and one site in Austria. PARTICIPANTS: Participants included 245 cataract patients, 127 of whom received the multifocal IOL bilaterally and 118 of whom received a monofocal IOL of nearly identical construction bilaterally. METHODS: Clinical data included visual acuity (VA), complications, and adverse events. Quality-of-life data were collected using a previously validated survey instrument at baseline, after first eye surgery, and after second eye surgery. RESULTS: At 3 months after surgery, patients who had received multifocal IOLs had significantly better uncorrected and distance corrected binocular near VA compared with patients who had received monofocal IOLs (mean uncorrected VA, 20/26 multifocal vs. 20/40 monofocal; mean distance corrected VA, 20/28 multifocal vs. 20/45 monofocal; P < 0.0001). Additionally, 96% of patients who had received multifocal IOLs and 65% of patients who had received monofocal IOLs achieved both 20/40 and J3 (Jaeger) or better uncorrected, binocular distance and near visual acuities (P < 0. 0001). Patients who had received multifocal IOLs were more likely than patients who had received monofocal IOLs to never wear glasses overall (32% multifocal vs. 8% monofocal; P < 0.0001). On a 4-point scale, patients who had received multifocal IOLs on average reported having between "a little bit" and "some" glare or halo, whereas patients who had received monofocal IOLs reported between "none" and "a little bit" of glare or halo (1.57 vs. 0.43; P < 0.001). Patients who had received multifocal IOLs rated their vision without glasses better overall at near and at intermediate distances (P < or = 0.002) and demonstrated better visual function for near tasks and social activities. CONCLUSIONS: Cataract patients who received multifocal IOLs at time of surgery obtained better uncorrected and distance corrected near VA and reported better overall vision, less limitation in visual function, less spectacle dependency, and more glare or halo than those who received traditional monofocal IOLs.

Photorefractive keratectomy versus laser in situ keratomileusis: comparison of optical side effects. Summit PRK-LASIK Study Group.

OBJECTIVE: This report presents patient-reported optical symptoms after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). DESIGN: Preoperative and postoperative patient surveys in a prospective, multicenter, randomized clinical trial. PARTICIPANTS: Two hundred twenty eyes of 220 patients entered the study; 105 were randomized to PRK and 115 were randomized to LASIK. INTERVENTION: All patients received a one-pass, multizone excimer laser ablation as part of either a PRK or LASIK procedure. Attempted corrections ranged from 6.00 to 15.00 diopters (D). MAIN OUTCOME MEASURES: Glare, halo, and monocular diplopia symptoms as reported by patients on questionnaires before surgery and at the 6-month follow-up. Comparison was made between symptoms when using optical correction before surgery and symptoms without correction after surgery. RESULTS: For both the PRK and LASIK groups analyzed individually, the difference in average glare index before surgery and after surgery was not statistically significant (P = 0.54 for PRK; P = 0.15 for LASIK; t test). Twenty-four PRK patients (41.4%) reported worsening of glare symptoms from baseline compared with 11 LASIK patients (21.6%); however, the difference between the two groups was not statistically significant (P = 0.086, chi-square test). Within the PRK group, the difference in average halo index before and after surgery was statistically significant (P = 0.0003, t test); in the LASIK group, it was not statistically significant (P = 0.1 1, t test). Thirty-four PRK patients (58.6%) reported worsening of halo symptoms from baseline compared with 26 LASIK patients (50.0%); this difference was not statistically significant (P = 0.086, chi-square test). For both the PRK and LASIK groups, the difference in average diplopia index before and after surgery was statistically significant (P < 0.0001 for PRK; 0.047 for LASIK; t test). Twenty-six PRK patients (44.8%) reported a worsening of monocular diplopia symptoms from baseline compared with 19 LASIK patients (35.8%); this difference was not statistically significant (P = 0.39, chi-square test). When changes in glare and halo from before surgery to after surgery were pooled as a glare-halo index, however, the PRK group did show a significantly greater likelihood of demonstrating an increase in symptoms compared with the LASIK group (P = 0.048, chi-square test). CONCLUSIONS: Optical sequelae of glare, halo, and monocular diplopia may occur in some patients after either both PRK or LASIK for moderate to high myopia; in contradistinction, many other patients' preoperative symptoms improve after surgery. On average, PRK patients show an increase in halo and diplopia symptoms, but not glare, after surgery, and LASIK patients show an increase in diplopia, but not glare and halo symptoms. There is a suggestion of a somewhat lesser tendency toward postoperative optical symptoms in LASIK compared with PRK treated eyes.

Driving simulation study: bilateral array multifocal versus bilateral AMO monofocal intraocular lenses.

PURPOSE: To determine whether differences exist in the driving performance of patients with bilateral Array multifocal intraocular lenses (IOLs) and those with bilateral AMO monofocal IOLs under low-contrast environmental conditions. SETTING: The Iowa Driving Simulator at the Center for Computer Aided Design, the University of Iowa, Iowa City, Iowa, USA. METHODS: This prospective study was a test-operator-masked, parallel-group comparison of the driving performance of 33 bilateral multifocal IOL patients and 33 bilateral monofocal IOL patients from the U.S. Array Multifocal study. Driving performance was evaluated under 3 poor visibility conditions (clear weather at night, clear weather at night in the presence of a glare source, and fog). Measures of performance included recognition rates and distances for signs, as well as detection rates, distances, and avoidance behaviors for hazards. Contrast acuity and sensitivity were also measured to evaluate possible correlations with driving performance. RESULTS: No statistically significant differences between the IOL groups were found in 26 of 30 comparisons (86.7%). The monofocal group performed better than the multifocal group in comparisons in which there were statistically significant differences: the percentage of correctly recognized warning signs at night in clear weather (P = .028), sign recognition distances for guide (P = .030) and warning (P = .036) signs in fog, and the detection distance for 1 of 4 hazards (suitcase; P = .026). Correlation coefficients between driving performance and low-contrast acuity and sensitivity were statistically significant; however, they were low and not likely predictive of driving performance. CONCLUSION: Differences between patients with bilateral multifocal IOLs and those with bilateral monofocal IOLs were detected; however, the results indicate no consistent difference in driving performance and safety.

Advances in refractive surgery. New options expand the scope of corrective procedures.

The Food and Drug Administration's approval of the excimer laser in 1995 heralded the age of laser refractive surgery in the United States. Since then, other advances in refractive surgery have spurred great public interest in and enthusiasm for these procedures. In this article, the authors review the major types of refractive surgery and discuss their indications, results, and complications.

A prospective comparative study of the AMO ARRAY zonal-progressive multifocal silicone intraocular lens and a monofocal intraocular lens.

OBJECTIVE: To evaluate the safety and effectiveness of a zonal-progressive multifocal silicone intraocular lens (IOL). DESIGN: Prospective, nonrandomized, fellow eye comparative trial. PARTICIPANTS: Four hundred fifty-six subjects were enrolled at 14 investigational sites in the United States; 400 subjects achieved 1-year follow-up. A subset of 123 subjects (102 at 1 year) were enrolled in a monofocal fellow eye control substudy; subjects were implanted with the multifocal IOL in one eye and a comparable monofocal IOL in the fellow eye. METHODS: Cataract extraction and implantation of a zonal-progressive multifocal silicone IOL was performed using the surgeon's standard technique. Subjects were followed at six postoperative examination intervals through 1 year. MAIN OUTCOME MEASURES: The key efficacy measures were mean uncorrected and corrected distance and near visual acuity at 1 year after surgery. RESULTS: In the monofocal fellow eye control substudy, the multifocal eyes showed a mean 2-line increase over monofocal eyes for uncorrected and distance-corrected near visual acuity (P < 0.0001). Mean uncorrected distance visual acuity was similar between multifocal and monofocal eyes (P = 0.116). A significantly higher proportion of bilateral multifocal subjects reported that they could function comfortably without glasses at near (81%, 96 of 118) compared with multifocal/monofocal subjects (56%; 93 of 165; P < 0.001) and unilateral multifocal subjects (58%; 56 of 97; P < 0.001). Low-contrast visual acuity was reduced in multifocal eyes by approximately 1 Snellen line. However, no perceived disadvantages attributable to the reduction in low-contrast acuity were found. Although the perception of halos and glare increased in the multifocal eyes, good visual function remained, and nearly all subjects were satisfied with the results of their surgery. CONCLUSIONS: In a large study that included a subset of subjects with paired eye compared with those with monofocal lenses, this zonal-progressive multifocal lens provided a high level of uncorrected and corrected distance vision, improved uncorrected and distance-corrected near vision, reduced spectacle dependency, and a high level of patient satisfaction despite some loss of low-contrast visual acuity and increased reports of halos and glare.

Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. A randomized prospective study.

OBJECTIVE: This report presents the results of a randomized clinical trial of photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK). DESIGN: A randomized, prospective multicenter clinical trial. PARTICIPANTS: A total of 220 eyes of 220 patients entered the study cohort: 105 randomized to PRK and 115 to LASIK. The mean preoperative manifest refraction spherical equivalent was -9.23 diopters (D) in the PRK group and -9.30 D in the LASIK group. INTERVENTION: All patients received a one-pass, multizone excimer laser ablation as part of either a PRK or LASIK procedure using the Summit Apex excimer laser. Attempted corrections ranged from 6.00 to 15.00 D. MAIN OUTCOME MEASURES: Data on uncorrected and spectacle-corrected visual acuity, predictability,and stability of refraction, corneal haze, and flap complications were analyzed. Patients were observed for up to 6 months. RESULTS: One day after surgery, 0 (0.0%) and 3 (4.5%) eyes in the PRK group saw 20/20 and 20/40 or better uncorrected, respectively, while 7 (10%) and 48 (68.6%) eyes in the LASIK group saw 20/20 and 20/40 or better, respectively. At 6 months after PRK, 13 (19.1%) and 45 (66.2%) eyes saw 20/20 and 20/40 or better, respectively, while after LASIK, 16 (26.2%) and 34 (55.7%) eyes saw 20/20 and 20/40 or better, respectively (odds ratio = 0.56 for likelihood of uncorrected visual acuity < 20/40 for PRK vs. LASIK, 95% confidence interval [CI] = 0.31-1.19). After PRK, 39 eyes (57.4%) were within 1.0 D of attempted correction compared with 24 eyes (40.7%) in the LASIK group (odds ratio = 0.50 for likelihood fo undercorrection 1.0 D for PRK vs. LASIK, 95% CI = 0.24-1.04); however, the standard deviation of the predictability was similar between groups: 1.01 D for PRK and 1.22 D for LASIK. From months 1 to 6, there was an average regression of 0.89 D in the PRK group and 0.55 D in the LASIK group. After PRK, eight eyes (11.8%) had a decrease in spectacle-corrected visual acuity of two Snellen lines or more; after LASIK, two eyes (3.2%) had a decrease of two lines or more (odds ratio = 3.89 for risk of loss of spectacle-corrected visual acuity for PRK vs. LASIK, 95% CI = 0.71-21.30). Only two eyes had postoperative spectacle-corrected visual acuity less than 20/32, however. CONCLUSIONS: Although improvement in uncorrected visual acuity is more rapid in LASIK than in PRK, efficacy outcomes in the longer term generally are similar between the two procedures. There is a greater tendency toward undercorrection in LASIK eyes using the specific laser and nomogram in this study, but the scatter in achieved versus attempted correction is similar, suggesting little difference in the accuracy of the two procedures. A suggestion of decreased propensity for loss of spectacle-corrected visual acuity in LASIK eyes requires further investigation.

Spherical and aspherical photorefractive keratectomy and laser in-situ keratomileusis for moderate to high myopia: two prospective, randomized clinical trials. Summit technology PRK-LASIK study group.

OBJECTIVE: Determine the outcomes of single-zone photorefractive keratectomy (SZPRK), aspherical photorefractive keratectomy (ASPRK), and laser in-situ keratomileusis (LASIK) for the correction of myopia between -6 and -12 diopters. DESIGN: Two simultaneous prospective, randomized, multi-center clinical trials. PARTICIPANTS: 286 first-treated eyes of 286 patients enrolled in one of two studies. In Study I, 134 eyes were randomized to SZPRK (58 eyes) or ASPRK (76 eyes). In Study II, 152 eyes were randomized to ASPRK (76 eyes) or to LASIK (76 eyes). INTERVENTION: All eyes received spherical one-pass excimer laser ablation as part of PRK or LASIK performed with the Summit Technologies Apex laser under an investigational device exemption, with attempted corrections between -6 and -12 diopters. MAIN OUTCOME MEASURES: Data on uncorrected and best spectacle-corrected visual acuity, predictability and stability of refraction, and complications were analyzed. Follow-up was 12 months. RESULTS: At 1 month postoperatively, more eyes in the LASIK group achieved 20/20 and 20/25 or better uncorrected visual acuity than PRK-treated eyes; at the 20/25 or better level, the difference was significant for LASIK (29/76 eyes, 38%) over SZPRK (10/58 eyes, 17%) (P = .0064). At all subsequent postoperative intervals, no difference was seen between treatment groups. Similarly, best corrected visual acuities were better for LASIK than all PRK eyes at 1 month postoperatively, and LASIK was better than SZPRK at 3 months follow-up (e.g., for 20/20 or better at 1 month, LASIK 50/76 eyes (66%) versus SZPRK 24/57 eyes (42%), P = .0066). PRK eyes had a mean loss of BCVA through 6 months, while LASIK eyes had a slight gain of mean BCVA through month 6; at 12 months, both ASPRK groups but not SZPRK continued to have a small mean loss of BCVA (e.g., compared to preoperative, mean BCVA at 12 months for SZPRK was + 0.3, LASIK was +.21, ASPRK I was -0.11, and ASPRK II -0.31 (SZPRK versus ASPRK II, P = .0116). Predictability was better for PRK than LASIK at all follow-up intervals (e.g., for manifest refraction spherical equivalent +/- 1.0 diopters at 6 months, ASPRK I 42/62 eyes (68%) versus LASIK 29/72 eyes (40%), P = .0014%). Stability was slightly but insignificantly less in the LASIK eyes compared to PRK eyes. All visual outcome measures were better for eyes with preoperative myopia between -6 and -8.9 D compared with eyes with myopia between -9 and -12 D. No consistent differences in refractive outcomes or postoperative corneal haze were seen between aspherical and single-zone ablations; haze diminished over 12 months and was judged to be vision-impairing in only one ASPRK eye. Microkeratome and flap complications occurred in 4 eyes, resulting in delay of completion of the procedure in 3 eyes but not causing long-term impairment. CONCLUSIONS: Improvement in uncorrected visual acuity and return of best corrected visual acuity was more rapid for LASIK than PRK, but efficacy outcomes in the longer term through 12 months were similar for all treatment groups. LASIK eyes tended toward undercorrection with the nomogram employed in this study compared to PRK, but the scatter was similar, suggesting little difference between these procedures for most patients by 6 months and thereafter. No consistent advantage was demonstrated between aspherical and single-zone ablation patterns. Predictability was much better for all procedures for corrections of -6 to -8.9 D compared with -9 to -12 D. Sporadic loss of best corrected vision in the PRK eyes not found in the LASIK eyes and other measures of visual function require further study.

Results of phase III excimer laser photorefractive keratectomy for myopia. The Summit PRK Study Group.

OBJECTIVE: The purpose of the study is to determine safety and efficacy outcomes of excimer laser photorefractive keratectomy (PRK) for the treatment of mild-to-moderate myopia. DESIGN: A prospective, multicenter, phase III clinical trial. PARTICIPANTS: A total of 701 eyes of 701 patients were entered in the study; 612 eyes were examined at 2 years after surgery. INTERVENTION: Intervention was photorefractive keratectomy using the Summit ExciMed UV200LA excimer laser (Summit Technology, Inc., Waltham, MA). The treatment zone diameter used was 4.5 mm in 251 eyes (35.8%) and 5 mm in 450 eyes (64.2%). Attempted corrections ranged from 1.50 to 6.00 diopters (D). MAIN OUTCOME MEASURES: Predictability and stability of refraction, uncorrected and spectacle-corrected visual acuity, refractive and keratometric astigmatism, corneal haze, contrast sensitivity, subjective reported problems of glare and halo, and patient satisfaction were the parameters measured. RESULTS: At 2 years, 407 (66.5%) eyes achieved 20/20 or better uncorrected visual acuity and 564 (92.5%) eyes achieved 20/40 or better visual acuity. Three hundred thirty-six (54.9%) eyes were within 0.5 D and 476 (77.8%) eyes were within 1.0 D of attempted correction. Stability of refraction improved with time; 86.8% of eyes were stable within 1.0 D from 6 to 12 months, 94% were stable from 12 to 18 months, and 96.3% were stable from 18 to 24 months. There was no evidence of progressive or late myopic or hyperopic refractive shifts. One hundred fourteen (18.6%) eyes gained 2 or more lines of spectacle-corrected visual acuity, whereas 42 (6.9%) eyes lost 2 or more lines; however, of the latter, 32 (76.2%) had spectacle-corrected visual acuity of 20/25 or better and 39 (92.9%) eyes had 20/40 or better. Four hundred forty-two (72.2%) corneas were clear, 138 (22.5%) showed trace haze, 20 (3.3%) mild haze, 9 (1.5%) moderate haze, and 3 (0.5%) marked haze. On patient questionnaires, 87 (29.7%) patients reported worsening of glare from preoperative baseline; 133 (50.1%) reported worsening of halo symptoms from baseline. CONCLUSIONS: Photorefractive keratectomy appears effective for myopic corrections of -1.50 to -6.00 D. Uncorrected visual acuity is maximized in most eyes by 3 months, although some patients require between 6 months and 1 year to attain their best postoperative uncorrected visual acuity and some may require from 1 to 2 years for stabilization of refraction. Refraction stabilizes progressively without evidence of late myopic or hyperopic refractive shifts. Optical sequelae of glare and halo occur in some patients treated with a 4.5- or 5-mm treatment zone.

Clinical assessment of long-term safety and efficacy of a widely implanted silicone intraocular lens material.

PURPOSE: To summarize the long-term safety and efficacy, in a large series of patients, of intraocular lenses made from a second-generation silicone material (AMO SLM-2/UV) widely used as an intraocular lens material. METHODS: This was a prospective study of adult patients who received posterior-chamber intraocular lenses with an optic composed of a high-index-of-refraction, ultraviolet-light-absorbing silicone (AMO SLM-2/UV). In 501 patients, clinical data through 3 years postoperative are presented. Postoperative measurements included spectacle-corrected visual acuity, occurrence of postoperative sight-threatening or lens-related complications, and adverse reactions. Results were compared with the standards established by the US Food and Drug Administration (FDA) for polymethylmethacrylate lenses. RESULTS: At 1 year, 95.2% (496/521) of all patients in group I achieved corrected visual acuity of 20/40 or better. This compared well with the standard reported for polymethylmethacrylate lenses (88%, 2,521/2,864). At 3 years, 94.3% (347/368) of best-case patients achieved corrected visual acuity of 20/40 or better. The rate of sight-threatening complications reported at the final postoperative examination at 3 years was 2.0% (10/501). The rate of Nd:YAG capsulotomy was 27.5% (138/501) through 3 years. CONCLUSION: Lenses made of the SLM-2/UV silicone material demonstrated safe and effective performance through long-term follow-up at a level equal to or better than established standards for polymethylmethacrylate lenses.

Retreatment of decentered excimer photorefractive keratectomy ablations.

PURPOSE: To present two cases of excimer photorefractive keratectomy decentration associated with visual distortion secondary to irregular astigmatism. METHOD: Patients were retreated with a repeat photorefractive keratectomy using a technique whereby the circle of adherent epithelium overlying the decentered ablation served as a mask. RESULTS: After retreatment, there was significant improvement in the patients' visual symptoms, decreased astigmatism on refraction, and better centration on corneal topography. CONCLUSION: This method appears to offer an effective means to treat photorefractive keratectomy ablation zone decentration by improving the abnormalities introduced by the initial decentration.

Postoperative retinal ischemia with self-sealing cataract surgery incisions.

PURPOSE: To report the potential for retinal ischemia caused by high intraocular pressure and to suggest a simple test for this condition. METHODS: We measured the intraocular pressure and directly examined the optic nerve head in four eyes of four patients at the conclusion of cataract surgery. RESULTS: With intraocular pressure above 40 mm Hg, elderly patients may abruptly lose the ability to perceive microscope illumination. The central retinal artery pulsated at these pressures. Light perception returned immediately upon reduction of intraocular pressure. CONCLUSION: Testing for light perception at the conclusion of surgery can indicate retinal ischemia with loss of light perception, which may occur during sealing of the cataract surgical wound.

Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery.

PURPOSE: The authors investigated the dimensional stability of incisions during phacoemulsification and small-incision intraocular lens (IOL) implantation. METHODS: Forty-six eyes undergoing temporal clear corneal phacoemulsification and folded silicone IOL implantation were measured with an internal-incision gauge after initial keratome entry, cataract removal, and folded IOL implantation. RESULTS: The initial incision created by a diamond keratome was wider than the physical keratome width by a mean of 0.16 mm. After completion of phacoemulsification and irrigation/aspiration, the incision further widened by a mean of 0.09 mm. Both forceps insertion of a three-piece silicone IOL and injector insertion of a plate haptic silicone IOL resulted in further incision enlargement by a mean of 0.26 mm. Widening the incision before IOL insertion did not eliminate even further incision expansion during the IOL insertion. CONCLUSIONS: The phacoemulsification incision enlarges at each step of the procedure. Irreversible incision stretching or incision tearing occurs, rather than reversible elastic incision deformation. Clinical studies that assume the initial keratome size equals the final incision size may be erroneous.

Hydrogel intracorneal lenses in aphakic eyes.

BACKGROUND: The theoretical benefits of synthetic keratophakia over conventional corneal lamellar procedures are the elimination of donor concerns and superior refractive predictability. Additionally, synthetic material can be inspected for optical quality and power, and it can be sterilized. Furthermore, visual recovery should be more rapid since epithelium is not removed from the central part of the cornea and the need for keratocyte repopulation is eliminated. OBJECTIVE: To present results on patients who received an intracorneal implant (Kerato-Gel, Allergan Medical Optics, Irvine, Calif) that was made from lidofilcon A, a glucose-permeable hydrogel with an equilibrium water content of 68%. METHODS: The intracorneal implants were implanted in 35 adult patients for correction of aphakia. Inclusion criteria excluded patients with aphakia who were candidates for intraocular lenses. RESULTS: A total of 19 patients were followed up through 2 years postoperatively. For 16 patients with 2-year postoperative refractive data, the average spherical equivalent was -0.63 +/- 2.07 diopters (D). At 2 years, 88% of patients were within +/- 3.00 D of plano and 50% were within +/- 1.00 D. the mean change in Snellen's line for corrected visual acuity was -3.25 lines at 2 years for all patients and -2.0 lines for a subgroup of five patients who were free of vision-limiting preoperative disease. CONCLUSIONS: Results suggest that this intracorneal implant is well tolerated by the cornea and can provide predictable refractive results in patients with high-risk aphakia. Limitations of the procedure are uneven microkeratome resections, loss of best-corrected visual acuity, and irregular astigmatism in some patients. Although these data show good evidence of biocompatibility of the implant material, technical surgical progress is needed to advance this procedure into clinical therapeutic practice.

Photorefractive keratectomy for myopia using a 4.5-millimeter ablation zone.

BACKGROUND: Argon fluoride (193 nm) excimer laser photorefractive keratectomy for myopia is under evaluation by the United States Food and Drug Administration. METHODS: We report a consecutive prospective series of 100 patients (one eye per patient) treated as part of the Phase IIB FDA-approved protocol, with 80 patients followed for 1 year. Patients' ages ranged from 21 to 62 years (mean, 35 years). The Summit Technology, Inc ExciMed UV200LA with a 4.5-mm diameter ablation was used. RESULTS: Baseline spherical equivalent refraction ranged from -2.00 to -6.90 diopters (D) (mean -4.60 D). Ninety-five percent of eyes reepithelialized by 72 hours. At 1 year, the difference between attempted and achieved correction was +/- 0.50 D for 42 eyes (53%) and +/- 1.00 D for 60 eyes (75%). During the first 6 months, there was a trend toward overcorrection and the majority of eyes showed some loss of initial refractive correction; 10 eyes (14%) changed by 1.00 D or more between 6 and 12 months. An uncorrected visual acuity of 20/25 or better was achieved by 50 eyes (63%) and 20/40 or better by 61 eyes (77%). Of the 10 eyes (12%) that lost two or more Snellen lines of spectacle-corrected or glare visual acuity, two had visual acuity of worse than 20/25. Central subepithelial corneal haze was absent to mild in 77 (96%) eyes at 12 months. CONCLUSIONS: Excimer laser photorefractive keratectomy as performed in this study was generally effective and safe in reducing simple spherical myopia. Further studies of the effect of a larger diameter ablation zone, smoother transitional corneal contours, and the effect of postoperative topical corticosteroids may lead to further improvements in outcome.