Safety of office-based lens surgery: U.S. multicenter study

PURPOSE

To evaluate the rate of adverse events after office-based lens surgery performed across multiple private practices in the United States.

SETTING

36 private practices across the U.S.

DESIGN

Retrospective multicenter study.

METHODS

This analysis included case records of all consecutive patients who underwent office-based lens surgery for visually significant cataract, refractive lens exchange, or phakic intraocular lens implantation between August 2020 and May 2022 at 36 participating sites across the U.S. The study outcome measures included the assessment of intraoperative and postoperative complications such as the incidence of unplanned vitrectomy, iritis, corneal edema, and endophthalmitis after lens surgery. The frequency of patients requiring a return to the operating room (OR) or referral to a retina surgeon and the frequency of patients requiring hospitalization or calling emergency services (911) for any reason were also evaluated.

RESULTS

The study reviewed 18 005 cases of office-based cataract or refractive lens surgery performed at 36 clinical sites. The rates of postoperative endophthalmitis, toxic anterior segment syndrome, and corneal edema were 0.028%, 0.022%, and 0.027%, respectively. Unplanned anterior vitrectomy was performed in 0.177% of patients. Although 0.067% of patients needed to return to the OR, 0.011% of patients were referred to the hospital.

CONCLUSIONS

The rate of adverse events for office-based cataract or refractive lens surgery is similar to or less than the reported adverse event rate for modern cataract surgery in the ambulatory surgery center setting.

Novel Cross-Linked Ocular Bandage Gel Improves Reepithelialization After Photorefractive Keratectomy: A Randomized, Masked Prospective Study

Purpose: To compare, in a masked manner, a novel cross-linked hyaluronic acid ocular bandage gel (OBG) versus standard-of-care bandage contact lens (BCL) plus artificial tears with respect to safety and effectiveness in healing epithelial defects created for photorefractive keratectomy (PRK). Methods: This was a randomized, reading center-masked, exploratory study. Forty-five patients (myopic without significant anisometropia) scheduled for bilateral PRK (9-mm epithelial defect) were randomized post-PRK to treatment with OBG 8 times daily for 3 days, followed by 4 times daily for 11 days (Group 1); OBG 4 times daily for 14 days (Group 2); or BCL and artificial tears (Control). A masked reading center used image analysis of digital slit lamp photos of the fluorescein-stained cornea to evaluate defect size during the 14-day postoperative follow-up period. Effectiveness endpoints were (1) time to complete closure of the corneal defect and (2) proportion of patients with complete healing on day 3 postoperatively, whose defect remained closed. Safety assessments included findings for adverse events and vision, Standard Patient Evaluation of Eye Dryness (SPEED^™) Questionnaire, slit lamp, intraocular pressure, and fundus examinations. Results: The proportion of patients with complete healing at 3 days was 73.3%, 86.7%, and 66.7% of patients in Groups 1, 2, and Control, respectively. On day 2, the mean wound size was 6%-26% smaller in Groups 1 and 2 compared with Control. No safety concern arose. SPEED scores were not significantly different across groups. Conclusion: OBG offers a well-tolerated and effective therapy for quickly reepithelializing the cornea following trauma, disease, or surgery.

Topography-Guided Refractive Astigmatism Outcomes: Predictions Comparing Three Different Programming Methods

Purpose

To identify the laser programming strategy that will achieve optimal refractive outcomes of LASIK with a topography-guided laser for eyes with a disparity between cylinder measured by manifest refraction and cylinder measured by topography.

Setting

Six surgeons at 5 clinical sites in the USA.

Design

Retrospective data review.

Methods

Preoperative, treatment, and postoperative data on 52 eyes that underwent topography-guided LASIK with the WaveLight EX500 Contoura^® Vision excimer laser ablation profile in which the vectors representing the preoperative refractive cylinder and the cylinder measured by the WaveLight^® Topolyzer™ VARIO Diagnostic Device (Vario cylinder) differed by >/= 0.50D and/or >/= 10 degrees of orientation were analyzed retrospectively. Data were contributed by six surgeons using the laser at 5 different clinical sites. Vector analysis of postoperative cylindrical refractive error and the actual laser programming strategy was used to calculate the cylindrical correction that would, theoretically, have completely eliminated postoperative refractive cylinder. This was compared to expected results using the preoperative manifest cylinder, the topographic cylinder, and the Phorcides Analytic Engine (Phorcides LLC, North Oaks MN; Phorcides). For analysis, subjects were stratified on the basis of the vector difference between Manifest and Topo cylinder (High, >0.75 D; and Low, ≤0.75 D).

Results

The poorest calculated theoretical outcomes were obtained with the manifest refraction (centroid: −0.43, 0.22; mean calculated error vector: 0.56 ± 0.42 D; p=ns). Better outcomes were obtained with the topographically measured refraction (centroid: 0.37, 0.02; mean calculated error vector: 0.47 ± 0.33 D; p=ns). The best outcomes were obtained with Phorcides (centroid: −0.15, 0.06; mean calculated error vector: 0.39 ± 0.28 D; p=ns). The mean error vector magnitude in the Phorcides Low group was significantly lower than for the Manifest and Topo Low groups (0.26 D vs 0.48 D and 0.33 D; p<0.01). The mean error magnitude in the Phorcides High group was nearly 0.25 D lower than for the Manifest High group (0.48 D vs 0.70 D; p<0.01), but was the same as for the Topo High group (0.48 D vs 0.48 D).

Conclusion

Our study suggests that using the topographically measured cylinder or the cylinder selected by Phorcides will produce more desirable refractive outcomes than entry of the preoperative refractive cylinder as the basis for correction of myopia and myopic astigmatism with the WaveLight Contoura Vision excimer laser.

Ability of a new crosslinked polymer ocular bandage gel to accelerate reepithelialization after photorefractive keratectomy

PURPOSE

To evaluate the safety and performance of a crosslinked thiolated carboxymethyl hyaluronic acid liquid-gel (CMHA-S) ocular bandage gel in accelerating reepithelialization of corneal defects created for photorefractive keratectomy (PRK).

SETTING

Three community-based clinical research sites.

DESIGN

Prospective case series.

METHODS

Patients scheduled for bilateral PRK had both eyes randomized immediately after PRK to Group 1 (ocular bandage gel 4 times a day for 14 days and bandage contact lens), Group 2 (ocular bandage gel 4 times a day for 14 days), or Group 3 (control; bandage contact lens and artificial tears 4 times a day for 14 days). Patients received a 9.0 mm epithelial defect for PRK and were followed through 28 days postoperatively. Safety assessments included adverse events, vision, pain, slitlamp, intraocular pressure, and fundus examinations. The primary performance endpoint was time to corneal reepithelialization after PRK.

RESULTS

The study comprised 39 patients. The ocular bandage gel was well tolerated. The time to reepithelialization was 3 days for 54.5%, 80.0%, and 45.5% of patients in Group 1, Group 2, and Group 3, respectively. Compared with measurements in the control group, the mean horizontal and vertical defect lengths in Group 2 (ocular bandage gel alone) were 36.9% and 29.0% smaller, respectively, by 1 day.

CONCLUSION

Crosslinked hyaluronic acid showed the ability to quickly reepithelialize the cornea and may promise a well-tolerated and effective therapy for ocular wound care after trauma, disease, or surgery.

U.S. Multicenter Clinical Trial of Corneal Collagen Crosslinking for Treatment of Corneal Ectasia after Refractive Surgery

PURPOSE

To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) for the treatment of corneal ectasia after laser refractive surgery.

DESIGN

Prospective, randomized, multicenter, controlled clinical trial.

PARTICIPANTS

One hundred seventy-nine subjects with corneal ectasia after previous refractive surgery.

METHODS

The treatment group underwent standard CXL, and the sham control group received riboflavin alone without removal of the epithelium.

MAIN OUTCOME MEASURES

The primary efficacy criterion was the change over 1 year of topography-derived maximum keratometry (K), comparing treatment with control groups. Secondary outcomes evaluated were corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent, endothelial cell count, and adverse events.

RESULTS

In the crosslinking treatment group, the maximum K value decreased by 0.7 diopters (D) from baseline to 1 year, whereas there was continued progression in the control group (1.3 D difference between treatment and control, P < 0.0001). In the treatment group, the maximum K value decreased by 2.0 D or more in 14 eyes (18%) and increased by 2.0 D or more in 3 eyes (4%). The CDVA improved by an average of 5.0 logarithm of the minimum angle of resolution (logMAR) letters. Twenty-three eyes (32%) gained and 3 eyes (4%) lost 10 or more logMAR letters. The UDVA improved 4.5 logMAR letters. Corneal haze was the most frequently reported crosslinking-related adverse finding.

CONCLUSIONS

Corneal collagen crosslinking was effective in improving the maximum K value, CDVA, and UDVA in eyes with corneal ectasia 1 year after treatment, with an excellent safety profile. CXL is the first approved procedure to diminish progression of this ectatic corneal process.

United States Multicenter Clinical Trial of Corneal Collagen Crosslinking for Keratoconus Treatment

PURPOSE

To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) for the treatment of progressive keratoconus.

DESIGN

Prospective, randomized, multicenter, controlled clinical trial.

PARTICIPANTS

Patients with progressive keratoconus (n = 205).

METHODS

The treatment group underwent standard CXL and the sham control group received riboflavin alone without removal of the epithelium.

MAIN OUTCOME MEASURES

The primary efficacy criterion was the change over 1 year of topography-derived maximum keratometry value, comparing treatment with control group. Secondary outcomes evaluated were corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent, endothelial cell count, and adverse events.

RESULTS

In the CXL treatment group, the maximum keratometry value decreased by 1.6 diopters (D) from baseline to 1 year, whereas keratoconus continued to progress in the control group. In the treatment group, the maximum keratometry value decreased by 2.0 D or more in 28 eyes (31.5%) and increased by 2.0 D or more in 5 eyes (5.6%). The CDVA improved by an average of 5.7 logarithm of the minimum angle of resolution (logMAR) units. Twenty-three eyes (27.7%) gained and 5 eyes lost (6.0%) 10 logMAR or more. The UDVA improved 4.4 logMAR. Corneal haze was the most frequently reported CXL-related adverse finding. There were no significant changes in endothelial cell count 1 year after treatment.

CONCLUSIONS

Corneal collagen crosslinking was effective in improving the maximum keratometry value, CDVA, and UCVA in eyes with progressive keratoconus 1 year after treatment, with an excellent safety profile. Corneal collagen crosslinking affords the keratoconic patient an important new option to decrease progression of this ectatic corneal process.

Comparison and analysis of FDA reported visual outcomes of the three latest platforms for LASIK: wavefront guided Visx iDesign, topography guided WaveLight Allegro Contoura, and topography guided Nidek EC-5000 CATz

Purpose

To compare and analyze the differences in visual outcomes between Visx iDesign Advanced WaveScan Studio™ System, Alcon Wavelight Allegro Topolyzer and Nidek EC-5000 using Final Fit™ Custom Ablation Treatment Software from the submitted summary of safety and effectiveness of the US Food and Drug Administration (FDA) data.

Methods

In this retrospective comparative study, 334 eyes from Visx iDesign, 212 eyes from Alcon Contour, and 135 eyes from Nidek CATz platforms were analyzed for primary and secondary visual outcomes. These outcomes were compared via side-by-side graphical and tabular representation of the FDA data. Statistical significance was calculated when appropriate to assess differences. A P-value <0.05 was considered statistically significant.

Results

The mean postoperative uncorrected distance visual acuity (UDVA) at 12 months was 20/19.25±8.76, 20/16.59±5.94, and 20/19.17±4.46 for Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. In at least 90% of treated eyes at 3 months and 12 months, all three lasers showed either no change or a gain of corrected distance visual acuity (CDVA). Mesopic contrast sensitivity at 6 months showed a clinically significant increase of 41.3%, 25.1%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. Photopic contrast sensitivity at 6 months showed a clinically significant increase of 19.2%, 31.9%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively.

Conclusion

FDA data for the three platforms shows all three were excellent with respect to efficacy, safety, accuracy, and stability. However, there are some differences between the platforms with certain outcome measurements. Overall, patients using all three lasers showed significant improvements in primary and secondary visual outcomes after LASIK surgery.

Short-term visual result after simultaneous photorefractive keratectomy and small-aperture cornea inlay implantation

PURPOSE

To report the short-term results of simultaneous photorefractive keratectomy (PRK) and small-aperture cornea inlay implantation (KAMRA) surgery in treating presbyopia.

METHODS

Simultaneous PRK and KAMRA inlay surgery was performed on 21 patients from July 2015 to March 2016. Follow-up exams were conducted at 1, 3, and 6 months postoperatively. Our patients were also divided preoperatively into three categories: myopic, hyperopic, and emmetropic. Over the 6-month period, the main outcome measures were uncorrected near visual acuity (UNVA), changes in best-corrected distance visual acuity, and mean spherical equivalent refraction.

RESULTS

At 6-month follow-up, 83% (10/12) of patients had a monocular UNVA of 20/40 or better, and 75% had a binocular UNVA of 20/40 (J5) or better. At 6 months, the overall mean refractive spherical equivalent (MRSE) was -0.60 D (±0.42 standard deviation [SD], range: -1.38 to -0.13) with a mean change of -0.43 D (±1.19 SD, range: -1.5 to 2.63) compared to preoperative data. Overall, 91% (10/11) of patients were within a ±0.5 D range of our target -0.75 D for KAMRA use. One-hundred percent (5/5) of the hyperopes, 50% (1/2) of emmetropes, and 100% (4/4) of myopes met the targeted range. At 6 months, the MRSE for the hyperopic subgroup (n=5) was 0.33 D (±0.20 SD), the MRSE for the emmetropic subgroup (n=2) was -1.19 D (±0.19 SD), and the MRSE for the myopic subgroup (n=4) was -0.66 D (±0.36 SD).

CONCLUSION

Based on preliminary results and a small sample size, it seems that simultaneous PRK and KAMRA is effective and predictable. There are multiple advantages in performing simultaneous PRK and KAMRA including a shorter recovery time and less steroid use than the two surgeries performed separately.

Removability of a small aperture intracorneal inlay for presbyopia correction

PURPOSE

To evaluate the safety of the corneal inlay removal procedure and the reversibility of visual acuities, corneal topography, and corneal biomicroscopy changes in a series of cases.

METHODS

Ten cases implanted with one of three versions of the AcuFocus Kamra Inlay (ACI 7000, 7000T, and 7000PDT; AcuFocus, Inc., Irvine, CA) were followed for a minimum of 6 months after corneal inlay removal.

RESULTS

The reason for removal was related to subjective dissatisfaction with visual symptoms (8 of 10 patients) such as night glare, photophobia, starburst, blurry vision, and halos. One case of removal was related to inadvertent thin flap and the final case was related to insufficient near vision. Mean uncorrected distance visual acuity (UDVA) and uncorrected near visual acuity (UNVA) was 0 ± 0.1 logMAR (Snellen 20/20) and 0.5 ± 0.2 logMAR (Snellen 20/40), respectively, preoperatively and 0.1 ± 0.1 logMAR (Snellen 20/25) and 0.5 ± 0.1 logMAR (Snellen 20/63), respectively, 6 months after corneal inlay removal. Mean corrected distance visual acuity (CDVA) and corrected near visual acuity (CNVA) was 0 ± 0.1 logMAR (Snellen 20/20) and 0 ± 0.1 logMAR (Snellen 20/20), respectively, preoperatively and 0 ± 0.1 logMAR (Snellen 20/20) and 0.1 ± 0.1 logMAR (Snellen 20/25), respectively, 6 months after corneal inlay removal. Mean root mean square (RMS) higher-order aberration (HOA) was 0.50 ± 0.12 (range: 0.30 to 0.70) preoperatively and 0.69 ± 0.14 (range: 0.48 to 0.95) 6 months after corneal inlay removal (P < .8). Weak positive correlation was found between Δt Implant-Removal (Δt I-R), RMS spherical, coma, and HOA at 6 months (Δt I-R vs RMS spherical was r = 0.2, r(2) = 0.5, P < .7; Δt I-R vs RMS coma was r = 0.8, r(2) = 0.6, P < .3; and Δt I-R vs HOA r = 0.8; r(2) = 0.6, P < .9).

CONCLUSION

This study suggests that after removal of the corneal inlay, corneal topography and corneal aberrometry are not permanently affected. In more than 60% of patients, CNVA, CDVA, UNVA, and UDVA were similar to the preoperative value.

Dilute brimonidine to improve patient comfort and subconjunctival hemorrhage after LASIK

PURPOSE

To investigate whether dilute brimonidine (0.025%) reduces patient discomfort, subconjunctival hemorrhage, and injection after LASIK without a significant increase in the rate of flap complications or surgical enhancements.

METHODS

This randomized, double-blind, prospective study enrolled 180 patients (360 eyes) in a contralateral eye comparison of topical dilute brimonidine, naphazoline/pheniramine, or Systane Ultra (Alcon Laboratories, Inc., Fort Worth, TX) administered shortly before LASIK for any indication. Patients were evaluated for subconjunctival hemorrhage, injection, and flap dislocation 1 hour and 1 day postoperatively. Patient questionnaires measuring patient comfort and ocular symptoms were administered at these same follow-up visits. Patients were examined for 3 months to determine similar outcomes for standard indices of safety, predictability, efficacy, and enhancement rates.

RESULTS

Scores of patient discomfort, subconjunctival hemorrhage, and injection were significantly lower in eyes treated with dilute brimonidine at the 1 hour and 1 day postoperative examinations. Refloats for mild-flap edge wrinkling were required in 3 brimonidine eyes (2.5%), 1 naphazoline/pheniramine eye (0.8%), and no control eyes, but this difference did not reach statistical significance (P = .18). There was no significant difference between eyes at 3 months in terms of visual acuity, refractive error, corrected distance visual acuity, or rate of enhancement.

CONCLUSIONS

Use of dilute brimonidine before LASIK reduces subconjunctival hemorrhage and injection and improves patient comfort after surgery. Flap edge wrinkling requiring refloat may still be a complication with dilute brimonidine.

Comparing conventional and wavefront-optimized LASIK for the treatment of hyperopia

PURPOSE

To compare differences in visual outcomes and induced spherical aberration after conventional and wavefront-optimized LASIK for the treatment of hyperopia.

METHODS

In a prospective, randomized, single-center clinical trial, 51 consecutive eyes underwent LASIK for the treatment of hyperopia. Eyes were divided between groups treated with conventional LASIK with the Alcon LADAR4000 excimer laser (n=25) and wavefront-optimized LASIK with the WaveLight ALLEGRETTO excimer laser (n=26). Refractive and visual outcomes, induced spherical aberrations, and contrast sensitivity were analyzed.

RESULTS

On postoperative day 1, 20% of eyes treated with a conventional profile had uncorrected visual acuity (UCVA) of 20/20 or better compared to 65% of eyes receiving wavefront-optimized treatment (P=.0011). By 6 months, UCVA was 20/20 or better in 72% and 84% of the conventional and wavefront-optimized treatment groups, respectively (P=.3254). At 6 months, the manifest refraction spherical equivalent was -0.21+/-0.47 diopters (D) and 0.16+/-0.27 D (P=.6469) whereas the cylinder was -0.41+/-0.47 D and -0.17+/-0.27 D (P=.0332) for the conventional and wavefront-optimized treatment groups, respectively. Induced spherical aberration was -0.54+/-0.32 microm and -0.42+/-0.21 microm for the conventional and wavefront-optimized treatment groups, respectively (P=.1195). The respective change in mesopic and photopic area under the log contrast sensitivity function was -0.05+/-0.29 and -0.05+/-0.23 for the conventional treatment group and 0.08+/-0.39 and 0.08+/-0.41 for the wavefront-optimized treatment group (P=.1970).

CONCLUSIONS

Wavefront-optimized (ALLEGRETTO) and conventional (LADAR4000) ablation predictably and safely correct low to moderate hyperopia. Wavefront-optimized ablation showed superior results with regards to rapid visual recovery and residual cylinder. Although not statistically significant, a trend towards less induced negative spherical aberrations and improved mesopic and photopic contrast sensitivity was noted with wavefront-optimized treatment.

Corneal endothelial cell density after femtosecond thin-flap LASIK and PRK for myopia: a contralateral eye study

PURPOSE

To compare the effect of femtosecond thinflap LASIK and photorefractive keratectomy (PRK) on postoperative endothelial cell density.

METHODS

In a prospective, randomized, contralateral, single-center clinical trial, 25 patients (mean age: 30+/-5 years [range: 21 to 38 years]) underwent PRK in one eye and thin-flap LASIK in the fellow eye for the correction of myopia using a wavefront-guided platform. The central corneal endothelial cell density was measured using the NIDEK Confoscan 4 preoperatively, and at 1 and 3 months postoperatively. Changes in endothelial cell density were analyzed over time between the two refractive techniques.

RESULTS

In PRK, the average preoperative endothelial cell density was 3011+/-329 cells/mm(2), which decreased to 2951+/-327 cells/mm(2) at 1 month (P=.5736) and 2982+/-365 cells/mm(2) at 3 months (P=.6513). In thinflap LASIK, the average preoperative endothelial cell density was 2995+/-325 cells/mm(2), which decreased to 2977+/-358 cells/mm(2) at 1 month (P=.5756) and 2931+/-369 cells/mm(2) at 3 months (P=.4106). No statistically significant difference was found between the two groups at 1 (P=.7404) or 3 (P=.3208) months postoperatively.

CONCLUSIONS

No statistically significant change was noted in endothelial cell density following either PRK or thin-flap LASIK for the treatment of myopia. Furthermore, no statistically significant difference was found between the two groups out to 3 months postoperatively, indicating that thin-flap LASIK is as safe as PRK with regards to endothelial health.

Wavefront-guided excimer laser ablation using photorefractive keratectomy and sub-Bowman's keratomileusis: a contralateral eye study

PURPOSE

To explain the basic science and clinical evidence that has led to the development of a new technique in corneal refractive surgery--sub-Bowman's keratomileusis (SBK).

METHODS

A comprehensive review of the literature and report of a contralateral eye study of 50 patients (100 eyes) enrolled at 2 sites (25 patients per site) and randomized according to the dominant eye was conducted. All eyes underwent a wavefront-guided refractive correction using the Alcon LADARVision4000 System. In one eye, an 8.5-mm, ETOH-assisted photorefractive keratectomy (PRK) was performed. In the second eye, an 8.5-mm, 100-microm flap was attempted using a 60 kHz IntraLase FS femtosecond laser. Pre- and postoperative tests included best spectacle-corrected visual acuity, uncorrected visual acuity, corneal topography, wavefront aberrometry, retinal image quality, contrast sensitivity, and biomechanical response of the cornea. Patients completed subjective questionnaires at each follow-up.

RESULTS

Clinical results demonstrate that SBK provides quicker visual recovery, although the data suggest that the 3- and 6-months results are similar in terms of visual outcomes. Reichert Ocular Response Analyzer results demonstrate that its impact on the cornea is similar to PRK.

CONCLUSIONS

This study indicates that SBK provides the visual recovery of a LASIK procedure with the Optical Response Analyzer results similar to PRK.

Effects of nonsteroidal ophthalmic drops on epithelial healing and pain in patients undergoing bilateral photorefractive keratectomy (PRK)

The present study, which was designed as a prospective, double-masked, randomized, controlled, single-site study, was conducted to compare the effects of 3 approved ophthalmic nonsteroidal anti-inflammatory drugs-nepafenac ophthalmic suspension 0.1% (Nevanac; Alcon Laboratories, Inc., Fort Worth, Tex), ketorolac tromethamine ophthalmic solution 0.4% (Acular LS; Allergan, Irvine, Calif), and bromfenac 0.09% (Xibromtrade mark; ISTA Pharmaceuticals, Irvine, Calif)-on corneal reepithelialization and postoperative pain control in patients undergoing photorefractive keratectomy. In addition to nonsteroidal anti-inflammatory drugs, each patient received an antibiotic-moxifloxacin hydrochloride ophthalmic solution 0.5% (nepafenac group) or gatifloxacin ophthalmic solution 0.3% (ketorolac and bromfenac groups). All treatments were administered 3 times daily beginning 1 d preoperatively and continuing for 1 wk postoperatively; prednisolone acetate 1.0% was administered concurrently 4 times daily. Bandage contact lenses were replaced at each postoperative visit for corneal staining and epithelial defect grading. Self-evaluation of pain relief was recorded on postoperative days 1 and 3 with the use of a visual analog scale. A total of 29 patients (58 eyes) were enrolled and underwent bilateral custom photorefractive keratectomy. Mean time to reepithelialization was 5.50+/-1.59 d for the nepafenac 0.1% group, 5.62+/-1.23 d for the ketorolac 0.4% group, and 7.25+/-2.53 d for the bromfenac 0.09% group. A significant difference was detected between nepafenac 0.1% and bromfenac 0.09% and between ketorolac 0.4% and bromfenac 0.09% (P<.05). Significant reductions in pain scores were observed with nepafenac 0.1% on day 1 (-1.13) and day 3 (-1.32), ketorolac 0.4% on day 3 (-0.88), and bromfenac 0.09% on day 3 (-0.83). No adverse events were reported. Eyes treated with nepafenac 0.1% or ketorolac 0.4% achieved complete reepithelialization significantly faster than those treated with bromfenac 0.09%. Daily contact lens removal and application of fluorescein may have delayed reepithelialization in the overall population; however, the effect would have been the same in all 3 groups. Pain relief with nepafenac 0.1% was achieved sooner than with ketorolac 0.4% or bromfenac 0.09%.

Double-masked study of the effects of nepafenac 0.1% and ketorolac 0.4% on corneal epithelial wound healing and pain after photorefractive keratectomy

Two NSAIDs--nepafenac 0.1% and ketorolac tromethamine 0.4%-were compared in terms of their effects on corneal reepithelialization and pain after photorefractive keratectomy (PRK) in a randomized, double-masked, contralateral eye, multicenter study. A total of 40 healthy adult patients who were undergoing sequential bilateral PRK received nepafenac 0.1% and ketorolac 0.4% in contralateral eyes, 1 drop 3 times daily for 3 d after bandage contact lens insertion. Patients were assessed on postoperative days 1, 3, 4, 5, and 7. At each visit, patients provided a general rating of pain. Each patient also assessed the sensation of each eyedrop following instillation (after-drop pain, irritation, burning/stinging, and overall comfort). Starting on day 3, epithelial defect size was assessed. Mean epithelial defect size was similar between treatments at each postoperative visit (P>.05). The average time-to-healing was 4.18 d for nepafenac 0.1% and 4.00 d for ketorolac 0.4% (P=.3134). No statistical difference was observed between nepafenac 0.1% and ketorolac 0.4% in mean postoperative pain scores (P>.05). On day 3, the nepafenac 0.1% group had significantly lower mean sensation scores than did the ketorolac 0.4% group for after-drop pain (P=.0090), irritation (P=.0007), and burning/ stinging (P=.0003). Mean overall comfort score was also significantly better for nepafenac 0.1% on day 3 (7.43 vs 6.41; P<.0001). Nepafenac 0.1% and ketorolac 0.4% provide postoperative pain relief after PRK surgery without associated adverse effects on corneal epithelial healing. Nepafenac 0.1% treatment may offer greater comfort upon instillation in patients who have undergone PRK.

Anterior Segment OCT Analysis of Thin IntraLase Femtosecond Flaps

PURPOSE

Anterior segment optical coherence tomography (OCT) was used to analyze thin flaps created with the IntraLase femtosecond laser (IntraLase Corp).

METHODS

Twenty-five eyes of 25 patients had flaps created with the 60 kHz IntraLase femtosecond laser prior to excimer laser ablation. The desired flap thickness was 110 microm with a diameter of 8.5 mm for all eyes. At 1 month postoperatively, all eyes were evaluated with the Visante anterior segment OCT (Carl Zeiss Meditec). Four thickness measurements were obtained across the length of the flaps at the meridians of 45 degrees, 90 degrees, 135 degrees, and 180 degrees. Thus, 16 thickness measurements were analyzed for each flap.

RESULTS

Flaps were uniform (planar) with a mean thickness of 112 +/- 5 microm (range: 87 to 118 microm). Average standard deviation within the individual flaps was 4 microm (range: 1 to 8 microm).

CONCLUSIONS

The IntraLase femtosecond laser creates thin, uniform (planar) flaps with high predictability and reproducibility.

Customized LASIK Treatment for Myopia: Relationship Between Preoperative Higher Order Aberrations and Refractive Outcome

PURPOSE

To analyze the effect of preoperative higher order aberrations on postoperative sphere and cylinder outcome.

METHODS

Three hundred thirty myopic eyes (mean: -3.32 +/- 1.54 diopters [D], range: -1.0 to -7.0 D) treated with customized ablation using the Technolas 217z laser (Bausch & Lomb) were followed through 6 months after LASIK. Pre- and postoperative visual acuity, higher order root mean square (RMS), third order RMS, and spherical aberration were compared to study the safety and efficacy of the treatment. The relationship between preoperative higher order aberrations and manifest refraction after LASIK was analyzed.

RESULTS

Following LASIK, 91.5% of eyes obtained an uncorrected visual acuity of > or = 20/20 and 70.3% of eyes obtained 20/16 without retreatment; 99% had a best spectacle-corrected visual acuity of > or = 20/20 (75.9% of eyes were within +/- 0.50 D). Mean value of significant increase in postoperative higher order aberrations was 0.12 +/- 0.18 microm (P<.0001). Increased spherical aberration was associated with increased myopia treatment (P<.0001). Greater positive spherical aberration after LASIK was significantly correlated to postoperative hyperopia (overcorrection). Change in third order RMS was significantly correlated to change in spherical equivalent refraction among eyes with postoperative astigmatism (P<.0001).

CONCLUSIONS

With the Bausch & Lomb Technolas 217z Zyoptix software, treatment of higher order aberrations, especially third order (coma and trefoil) and spherical aberration, significantly improved postoperative refractive status.

The effect of different monovision contact lens powers on the visual function of emmetropic presbyopic patients (an American Ophthalmological Society thesis)

PURPOSE

To evaluate the effects of three increasing powers of monovision contact lenses on both objective and subjective vision in emmetropic presbyopic patients.

METHODS

A prospective single-center study was conducted on 50 emmetropic presbyopic patients with a mean age of 55.4 +/- 4.3 years (range, 50 to 66). Each patient wore for 1 week a +0.75 D, +1.50 D, and +2.50 D contact lens in the nondominant eye. Objective testing after each week included near and distance visual acuity, distance stereopsis, distance contrast sensitivity, and measurement with two different aberrometers of spherical equivalent, defocus, spherical aberration, and total higher-order aberrations. Subjective testing included questionnaire responses regarding vision under various conditions after 1 week with each lens power. Statistical tests were performed to determine significant differences from pretreatment.

RESULTS

Binocularly, mean uncorrected near visual acuity increased in both eyes (P < .01) with each increase in contact lens power. Monocular distance vision decreased significantly with each increasing lens power, but binocular distance vision remained unchanged from pretreatment. Distance stereopsis decreased significantly with increasing contact lens powers (P < .01 with the +2.50 D lens power). Photopic and mesopic distance contrast sensitivity decreased significantly with progressive increase in power. Wavefront analysis showed a change in defocus in the myopic direction, but no increase in higher-order aberrations.

CONCLUSIONS

In emmetropic presbyopes, near vision improved with increased lens power, but distance vision was degraded objectively and subjectively. The +1.50 D power provided optimal near and distance vision for monovision contact lens wear, as measured by a patient questionnaire and a series of eight tests for evaluating various aspects of visual function. The objective and subjective tests used in this study will provide a baseline for evaluation of surgical procedures performed for near vision enhancement.

Alcon LADARWave CustomCornea Retreatments

PURPOSE

To present our experience performing wavefront-guided ablations for the treatment of residual refractive error following previous refractive surgery.

METHODS

Four different cases are presented-1) primary wavefront-guided LASIK; 2) wavefront-guided lift-flap LASIK retreatment; 3) wavefront-guided photorefractive keratectomy (PRK) retreatment; and 4) wavefront-guided PRK over radial keratotomy retreatment. All procedures were performed with the Alcon CustomCornea laser platform. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and wavefront analysis (6.5-mm pupil) were performed preoperatively and 3 months after CustomCornea retreatment. The Alcon LADARWave device was used for wavefront measurements.

RESULTS

Total lower order and higher order aberrations were decreased following wavefront-guided retreatment, resulting in improved quality of vision. The maximum target offset (+ 0.75 diopters) can be used to prevent an overcorrection of defocus (myopia) when treating a significant amount of spherical aberration.

CONCLUSIONS

Wavefront-guided ablation was an effective treatment for residual lower and higher order aberrations following previous refractive surgery. Custom ablation treatment algorithms need to be developed specifically for retreatment procedures.

Ocular Cyclotorsion During Customized Laser Ablation

PURPOSE

To compare the measured difference and degree of cyclotorsion in eyes undergoing customized laser ablation between the time of wavefront measurement and laser refractive surgery.

METHODS

The degree of cyclotorsion was measured in 1019 consecutive eyes of 732 patients who underwent wavefront-guided corneal ablation for the treatment of myopia with or without astigmatism with the Alcon LADARVision excimer laser. Prior to obtaining the wavefront measurement, the horizontal axis of each eye was marked. Cyclotorsional alignment was measured on the supine patient prior to beginning the laser.

RESULTS

The predominant trend was for excyclotorsion. The total range of torsion in degrees was 0.5 degrees to 17.5 degrees (mean: 4.05 +/- 2.9 degrees). Cyclotorsion > 2 degrees occurred in 68% of all eyes. In the right eyes, 83% excyclotorted, 14% incyclotorted, and 3% displayed no torsion. In the left eyes, 62% excyclotorted, 34% incyclotorted, and 4% exhibited no torsion. In a subset of 112 patients undergoing simultaneous bilateral surgery, 46% displayed bilateral excyclotorsion and 1.7% displayed bilateral incyclotorsion.

CONCLUSIONS

In this study, the majority of eyes had a low to moderate amount of cyclotorsion observed with the change of orientation from seated to supine position. Excyclotorsion was the predominant pattern. Proper registration prior to wavefront-guided corneal ablation is essential for proper correction of astigmatism and higher order aberrations to achieve optimal visual outcomes.

A Comparison of Therapeutic Regimens Containing Moxifloxacin 0.5% Ophthalmic Solution and Gatifloxacin 0.3% Ophthalmic Solution for Surgical Prophylaxis in Patients Undergoing LASIK or LASEK

The purpose of these two studies was to compare the safety and tolerability of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% ophthalmic solution for use with laser-assisted in situ keratomileusis (LASIK) and laser-assisted subepithelial keratomileusis (LASEK) patients. Treatment with the two antibiotic regimens was randomly assigned to fellow eyes of each patient. The LASIK study showed no difference between the two therapies in terms of visual acuity, pupil size, SPK, edema, haze, day- and nighttime glare, halos, clarity of day or night vision, and dry eye symptoms up to 1 week after surgery. Patients reported no preference between the two antibiotics on the basis of ease of use, irritation, redness, itching, gritty, sandy or scratchy feeling, speed of recovery, overall vision, or overall comfort up to 7 days after LASIK surgery. Corneal healing after LASEK surgery was equivalent for the antibiotic regimens containing moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% ophthalmic solution. When comparing safety and tolerability, these findings suggest an equivalent role for these fluoroquinolone antibiotics in surgical prophylaxis.

Femtosecond laser versus mechanical keratome flaps in wavefront-guided laser in situ keratomileusis

PURPOSE

To compare the outcomes of wavefront-guided laser in situ keratomileusis (LASIK) performed using the IntraLase femtosecond laser with the outcomes using the Hansatome mechanical microkeratome.

SETTING

Private clinic, Overland Park, Kansas, USA.

METHODS

In a prospective contralateral-eye study performed under institutional review board supervision, 51 consecutive patients (102 eyes) had bilateral wavefront-guided LASIK for myopia using the Alcon LADARVision laser. One eye of each patient was randomized to have the flap created with the IntraLase femtosecond laser and the other flap using a standard compression head Hansatome microkeratome. All other treatment parameters were the same.

RESULTS

The IntraLase group had significantly better mean uncorrected visual acuity (UCVA) at all intervals from 1 day to 3 months postoperatively. The mean spheroequivalent at 3 months was more myopic with the Hansatome (-0.34 diopter [D] +/- 0.28 [SD]) than with the IntraLase (-0.19 +/- 0.24 D) (P<.01). The mean residual astigmatism at 3 months was also significantly higher in the Hansatome group than in the IntraLase group (0.32 +/- 0.25 D and 0.17 +/- 0.20 D, respectively) (P<.01). The differences in UCVA persisted after spheroequivalent outcomes were controlled for but equilibrated when the analysis was modified to control for manifest postoperative astigmatism. Aberrometry showed significantly higher astigmatism and trefoil in the Hansatome group. Recovery of corneal sensation and epithelial integrity was similar between groups.

CONCLUSIONS

The statistically better UCVA and manifest refractive outcomes after LASIK with the IntraLase femtosecond laser may be the result of differences in postoperative astigmatism and trefoil. These findings are consistent with previous findings of better astigmatic outcomes with the IntraLase laser and may have clinical significance for wavefront-guided treatments.

Randomized Comparison of Custom Laser in situ Keratomileusis With the Alcon CustomCornea and the Bausch & Lomb Zyoptix Systems: One-month Results

PURPOSE

To compare the early visual results of custom laser in situ keratomileusis (LASIK) outcomes for two different excimer laser systems.

METHODS

This is a preliminary report of an ongoing prospective study that evaluated 30 patients (60 eyes) who were randomized to one of two custom LASIK treatment groups: 15 patients (30 eyes) with the Alcon CustomCornea laser system (Alcon Laboratories Inc, Fort Worth, Tex) and 15 patients (30 eyes) with the Bausch & Lomb Zyoptix laser system (Bausch & Lomb, Rochester, NY). These matched patients were required to qualify for treatment with both custom laser systems. All flaps were created with the IntraLase femtosecond laser (IntraLase Corp, Irvine, Calif) using a superior hinge. Early outcome measures are uncorrected visual acuity (UCVA) at 1 day, 1 week, and 1 month postoperative; manifest refractions at 1-month follow-up; and a comparison of 1-month postoperative UCVA to preoperative best spectacle-corrected visual acuity (BSCVA). Wavefront, topography, contrast sensitivity, and subjective questionnaires were also performed and will be reported after 3-month follow-up.

RESULTS

At 1 month, the percentage of eyes with UCVA of 20/20 and 20/40 were similar with 93% and 100%, respectively, for CustomCornea eyes and 90% and 97%, respectively, for Zyoptix eyes. A difference between the two groups is in the percentage of eyes with UCVA of 20/16, 20/12.5, and 20/10 with 80%, 47%, and 13%, respectively, for CustomCornea and 70%, 10%, and 0%, respectively, for Zyoptix. The mean residual spherical equivalent refraction was +0.01 +/- 0.34 diopters (D) for CustomCornea and -0.04 +/- 0.38 D for Zyoptix. The two groups are similar at +/-1.00 D of intended correction, with CustomCornea 100% and Zyoptix 97%. However, +/-0.25 D the CustomCornea group was 10% more accurate at 73% versus 63% for the Zyoptix group. The efficiency ratio (postoperative UCVA compared to preoperative BSCVA) was greater for the CustomCornea group at 20/20, 20/16,20/12.5, and 20/10 levels.

CONCLUSION

Custom LASIK with CustomCornea and Zyoptix is safe and effective and produces excellent early visual outcomes. This study demonstrates that current standard metrics for reporting refractive surgery visual outcomes are not adequate for evaluating wavefront-guided laser vision correction procedures. Amending the standard reporting metrics to include visual outcomes at the 20/16, 20/12.5, and 20/10 levels; accuracy at the +/-0.25 D of attempted; and postoperative UCVA compared to preoperative BSCVA will improve our ability to analyze wavefront-guided outcomes.

First 100 CustomCornea Commercial Eyes

PURPOSE

With the advent of wavefront-guided custom abalation we not only try to reach a target of 20/20 vision, but strive for improvement in what has always been most important--the quality of this vision.

METHODS AND RESULTS

Insights are presented, based on clinical experience at Durrie Vision with our first 100 commercial CustomCornea eyes. We highlight key points for preparing a clinical practice for this new technology, such as staff training, marketing, and pricing. We discuss technical aspects such as patient selection and target adjustment as they relate to the Alcon LADARWave system.

CONCLUSION

In our practice we have thus far had clinical success with CustomCornea; patient acceptance has been high, and by closely monitoring our first few patients we were able to reduce the number of future enhancements.

Two-year outcomes of intrastromal corneal ring segments for the correction of myopia

OBJECTIVE

To evaluate the safety and efficacy of Intrastromal Corneal Ring Segments (ICRS) for the correction of myopia.

DESIGN

Nonrandomized, comparative trial.

PARTICIPANTS

Patients enrolled in the United States Food and Drug Administration phase II and phase III clinical trials of the ICRS had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, myopia of -1.00 to -3.50 diopters (D), and a cylindrical correction of 1.00 D or less as measured by manifest refraction.

INTERVENTION

Surgical correction of myopia with an ICRS.

MAIN OUTCOME MEASURES

Efficacy was assessed by predictability of refractive outcome (deviation from predicted cycloplegic refraction spherical equivalent), stability of refractive effect, and postoperative uncorrected visual acuity. Safety was assessed by adverse events, maintenance or loss of preoperative BSCVA, and induced manifest refraction cylinder.

RESULTS

Four hundred fifty-two patients were enrolled at 11 investigational sites in both studies. Of the 454 surgical attempts, 449 received an ICRS in one eye (0.25, 0.30, and 0.35 mm in 148, 151, and 150 eyes, respectively). First surgeries were attempted in 452 patients. An ICRS was successfully implanted in 447 initial eyes, and 5 surgeries were discontinued. Of the five discontinued surgeries, three patients subsequently exited from the study, and two patients went on to have the ICRS implanted in the second eye, bringing the total number of successful implants to 449 patient eyes. Month 24 postoperative follow-up was completed on 358 patients (80%). At month 24, 328 of 354 eyes (93%) were within +/-1.00 D of predicted refractive outcome. Refraction changed by 1 D or less in 97% of eyes (421/435) between 3 and 6 months after implantation and in 99% (343/348) between months 18 and 24. Before surgery, 87% of eyes (390/448) saw worse than 20/40 uncorrected; 24 months after surgery, 55% of eyes (196/358) saw 20/16 or better, 76% (271/358) saw 20/20 or better, and 97% (346/358) saw 20/40 or better. Although two eyes (2/358; 0.5%) lost two or more lines of BSCVA at 24 months; visual acuity in both was 20/20 or better. Intraoperative complications included anterior corneal surface perforation (three eyes) and anterior chamber perforations (two eyes, one during an attempted exchange procedure); all healed spontaneously without suturing and without loss of BSCVA. The ICRS was repositioned in five eyes to increase correction. Postoperative complications in one eye each were infectious keratitis, shallow segment placement, and loss of two lines of BSCVA at two or more consecutive examinations (subsequently regained).

CONCLUSIONS

The ICRS safely, predictably, and effectively reduced or eliminated myopia of -1.00 to -3.50 D. The refractive effect was stable over time.

Intraocular lens power calculations using corneal topography after photorefractive keratectomy

PURPOSE

To report two patients (two eyes) with previous photorefractive keratectomy, who subsequently underwent cataract extraction years later.

DESIGN

Case reports.

METHODS

Corneal topography was used to determine corneal power used in intraocular lens power calculations.

RESULTS

In two eyes of two patients, intraocular lens calculations after photorefractive keratectomy were inadequate, which resulted in a hyperopic postoperative refractive error requiring implantation of a piggyback intraocular lens.

CONCLUSION

Corneal topography to determine corneal power in patients with previous photorefractive keratectomy may result in unpredictable intraocular lens power calculations. The clinical history method is the standard to determine corneal power and should be considered in intraocular lens calculations before cataract surgery. We recommend supplying refractive patients with preoperative data for use in future formulas for intraocular lens selection.

LASIK enhancements

As the field of refractive surgery continues to evolve, an increasing number of surgical options are available for LASIK enhancements. Nonetheless, older methods such as AK continue to play an important role in enhancement procedures. Improvements in instruments and techniques allow for previously made LASIK flaps to be safely lifted for additional myopic or hyperopic ablations. Newer methods such as Intacs placement provide an effective option for patients who are not good candidates for further ablative procedures. These advancements allow refractive surgeons to treat a wider range of myopia, hyperopia, and astigmatism effectively in eyes with a history of LASIK surgery.

Intrastromal Corneal Ring Segments: Reversibility of Refractive Effect

PURPOSE

To evaluate the reversibility of refractive effect following removal of the ICRS (intrastromal corneal ring segments; Intacs).

METHODS

Data from 34 eyes from which ICRS were removed during United States FDA Phase II and III clinical trials were evaluated with regard to segment size, loss or change of best spectacle-corrected visual acuity (BSCVA), any change of uncorrected visual acuity (UCVA), manifest spherical equivalent refraction, manifest cylinder refraction, stability of manifest cylinder refraction, and subjective visual symptoms.

RESULTS

Out of 725 initial or contralateral eyes placed with the ICRS during Phase II and III clinical trials, segments were removed from 34 eyes (4.7%). Other than one (1/725, 0.1%) safety related ICRS removal, 30/725 (4.1%) were due to visual symptoms. ICRS removal was accomplished under topical anesthesia without complications in all eyes. The mean length of time the segments remained in the cornea after initial surgery was 10.3 +/- 5.4 months. At 3 months after ICRS removal, 21 eyes had monitored data available and were within +/-1 line or 10 letters of their preoperative BSCVA. Twenty eyes (20/21, 95%) returned to within +/-1.00 D of their preoperative manifest spherical equivalent refraction. All eyes had a stable refraction at the 3-month examination after removal, and a manifest spherical equivalent refraction within +/-1.00 D of their 1-month examination after removal. Nineteen eyes (19/21, 90%) returned to within +/-2 lines and 16 eyes (16/21, 76%) returned to within +/-1 line of preoperative UCVA.

CONCLUSION

The ICRS (Intacs) was easily and safely removed, and eyes returned to preoperative refractive status within 3 months.

Photoastigmatic Refractive Keratectomy in Myopes

PURPOSE

Photoastigmatic refractive keratectomy (PARK) was studied in a multi-center clinical trial. The Nidek EC-5000 excimer laser was evaluated for its effect on refraction, visual acuity, and safety measures as part of a U.S. Food and Drug Administration (FDA) regulated study.

METHODS

Eight U.S. centers enrolled adults with eyes having refractive astigmatism up to 4.00 D and a myopic spherical equivalent refraction up to -8.00 D. Results are reported for 749 eyes of 486 patients with at least 6 months follow-up. The rectangular beam scanning Nidek EC-5000 used a 5.5-mm-diameter treatment zone, a 7.0-mm-diameter peripheral blend zone, and a 40 Hz pulse rate for surface treatment of myopic astigmatism. Nomogram corrections to machine settings were required to achieve the desired results.

RESULTS

Preoperative average spherical equivalent refraction of -4.90+/-1.74 D was reduced to -0.02+/-0.79 D at 6 months. Refractive stability was established at 3 months. Over 62% of eyes were within +/-0.50 D of desired correction at 6 months, with over 86% within +/-1.00 D. Uncorrected visual acuity improved by an average of 10 Snellen lines; over 64% of eyes saw 20/20 or better uncorrected and over 93% saw 20/40 or better uncorrected at 6 and 12 months. PARK treatment effectively reduced astigmatism with little average axis error or magnitude error. Corneal haze and safety concerns were minimal.

CONCLUSIONS

Photoastigmatic refractive keratectomy using the Nidek EC-5000 excimer laser provided significant reduction of myopia and astigmatism, with minimal complications.

Adjustability of refractive effect for corneal ring segments

PURPOSE

To evaluate the safety and efficacy of adjustability of the refractive effect of intrastromal corneal ring segments (ICRS, Intacs).

METHODS

Data from four patients who had their initial Intacs removed and exchanged for new Intacs of different thickness sizes during a United States Food and Drug Adminstration Phase II clinical trial were evaluated with regard to segment size, reasons for exchange, duration within the cornea before exchange procedure, loss or change of spectacle-corrected visual acuity, change of uncorrected visual acuity, manifest refraction, cycloplegic refraction, topography after exchange, and stability of refraction.

RESULTS

The exchange procedure was performed in two patients due to undercorrection and in two for overcorrection. The length of time the segments remained in the cornea after initial surgery varied from 6 to 15 months (mean, 10.25 +/- 4.03 mo). The most recent examination occurred between 4 to 18 months (mean, 10.0 +/- 6.32 mo) following the exchange procedure and showed improved uncorrected visual acuity with a range from 20/16 to 20/20 and a gain of 2 to 7 lines of uncorrected visual acuity compared to baseline. No eyes lost any lines of spectacle-corrected visual acuity following the exchange procedure and all preserved their preoperative spectacle-corrected visual acuity of 20/16. The intended refractive correction was achieved in the first few days of the exchange procedure and remained stable.

CONCLUSION

In these four eyes that were over- or undercorrected after initial Intacs placement, segment thickness sizes were exchanged after 6, 8, 12, and 15 months without complication and with final uncorrected visual acuities of 20/16 to 20/20.

Improvement of visual function with glare testing after photorefractive keratectomy and radial keratotomy

PURPOSE

To evaluate the effect of a glare source on visual function in patients after photorefractive keratectomy and radial keratotomy.

METHODS

Thirteen patients (22 eyes) who underwent photorefractive keratectomy and 20 patients (40 eyes) who underwent radial keratotomy were evaluated in this cross-sectional study. LogMAR visual acuity and contrast sensitivity were measured. Pupils were measured with the Rosenbaum card. A halogen/tungsten glare source approximated the luminance of headlights of an oncoming car at 100 feet.

RESULTS

In the photorefractive keratectomy and radial keratotomy groups, pupils were significantly smaller (P<.01) and the pupillary clearance of the ablation zone in photorefractive keratectomy and the clear zone in radial keratotomy were significantly larger under the glare condition (P<.01). In the photorefractive keratectomy group, visual acuity and contrast sensitivity under the glare condition were significantly higher than in the no-glare condition (P = .02). In the radial keratotomy group, contrast sensitivity under the glare condition was significantly higher than under the no-glare condition (P = .001 to .003).

CONCLUSIONS

After photorefractive keratectomy or radial keratotomy, the traditional glare source constricted the pupil and partially masked the optical aberrations, which resulted in an improvement in visual function. A "pupil-sparing" aberration test is needed for evaluation of visual function after refractive surgery.

One-year results from the phase III investigation of the KeraVision Intacs

BACKGROUND

Limitations of the surgical correction for myopia include inaccuracy, instability, treatment of the central optical zone, and lack of reversibility. KeraVision Intacs offer an alternative that addresses these shortcomings.

METHODS

We present 1 year of follow-up information on 95 subjects enrolled in the United States Food and Drug Administration Phase III clinical trials.

RESULTS

At 1 year, 99% of patients (89 of 90) had 20/40 uncorrected vision or better. Ninety-two percent of eyes (83 of 90) were within 1.00 D of intended correction and 76% of eyes (68 of 90) were within 0.50 D of intended correction. Stability was achieved at 3 months, with 96% of subjects (86 of 90) having less than 1.00 D of change from their previous examination. In a substudy, 89% eyes (58 of 65) varied within +/- 0.50 D over the course of a day. Corneal curvature changed as predicted, resulting in a prolate aspheric shape within the central optical zone. Most complications or adverse events experienced were managed with additional medication or surgical intervention, resulting in a favorable outcome for subjects.

CONCLUSIONS

KeraVision Intacs are effective, predictable, stable, and safe. This additive technique may also offer reversibility.

Topographic predicted corneal acuity with intrastromal corneal ring segments

PURPOSE

To evaluate predicted optical quality of the central anterior corneal surface before and after the intrastromal corneal ring segment (ICRS) refractive procedure using a clinical videokeratoscope and software index developed for that purpose.

METHODS

Predicted corneal acuity, a topographically derived index provided with the EyeSys System 2000 videokeratscope, representing potential optical quality of the cornea, was assessed preoperatively and at postoperative month 3 in 94 eyes that received an ICRS to treat -1.00 to -6.00 D of myopia. Predicted corneal acuity was calculated by determining the difference between a measured cornea and its best-fit ellipses for reflected ring circumferences within the central 3 mm diameter zone.

RESULTS

Preoperative predicted corneal acuity was 20/10 in 92 of 94 eyes (98%). At month 3 after the ICRS procedure, 48 (51%) of moderately myopic eyes were corrected to 20/20 or better, 96% (90 eyes) were corrected to 20/40 or better, and 98% of eyes (92 eyes) had a predicted corneal acuity of 20/10. For the eyes with a predicted corneal acuity of 20/10, spectacle-corrected visual acuity was normally distributed between 20/10 and 20/25.

CONCLUSION

Predicted corneal acuity did not change significantly from baseline in eyes with an ICRS. This suggests that topographic irregularities in the central 3 mm of the cornea detectable by predicted corneal acuity software were not induced in the central cornea with the ICRS.

Phototherapeutic keratectomy for recurrent erosion syndrome in anterior basement membrane dystrophy

PURPOSE

To determine the outcome of patients who received phototherapeutic keratectomy (PTK) for recurrent erosion syndrome due to anterior basement membrane dystrophy (ABMD).

DESIGN

A retrospective, noncomparative case series.

PARTICIPANTS

Forty-eight eyes of 43 consecutive patients who underwent PTK for recurrent erosions occurring in ABMD at the Hunkeler Eye Center from 1991 to April 1995. All patients had previously failed at least one method of medical or surgical treatment for recurrent erosions and had slit-lamp findings of ABMD on initial evaluation.

INTERVENTION

The eyes each underwent manual superficial keratectomy and PTK with the Summit Omnimed excimer laser.

MAIN OUTCOME MEASURES

Data were analyzed by a retrospective chart review for 1, 3, 6, and 12 months for the 36 eyes with at least 12 months of follow-up data available. They were analyzed for preoperative and postoperative visual acuity, change in spherical equivalent, recurrence rate, and patient satisfaction.

RESULTS

The preoperative mean visual acuity was not statistically significantly different at 1 month after PTK. Statistically significant improvement in mean visual acuity was present at 3, 6, and 12 months. Recurrence of symptoms of recurrent erosion was present in 5 (13.8%) of 36 eyes during the 12-month follow-up period, which was managed with repeat PTK over the area of the cornea initially treated with PTK; 1 of 5 required a third PTK treatment. All recurrences presented within 6 months of PTK or repeat PTK. The mean dioptric change in spherical equivalent was not statistically significant. Patient satisfaction levels after PTK for recurrent erosions in ABMD were assessed in 21 (58%) of 36 patients on a scale of 0 to 5 (5 = most satisfied); the mean response was 4.14 of 5.

CONCLUSIONS

Phototherapeutic keratectomy is an effective treatment for recurrent erosions occurring in the setting of ABMD, is well tolerated, and may improve visual acuity. The rate of recurrence of erosions in ABMD treated with PTK is low during a 12-month follow-up period.

Lift-flap retreatment after laser in situ keratomileusis

PURPOSE

To demonstrate the effectiveness of lifting the flap for retreatment of undercorrected eyes after laser in situ keratomileusis (LASIK).

METHODS

We reviewed the results of 11 LASIK patients (12 eyes) who underwent retreatment for residual myopia by lifting the previously cut flap. This was followed by treatment with the Summit Apex excimer laser and repositioning of the flap. Average time prior to retreatment was 5 months (range, 1 to 9 mo). Follow-up was 100% at 3 months after retreatment.

RESULTS

The average preoperative spherical equivalent refraction was -8.73 D; average prior to retreatment was -2.24 D (range, -0.67 to -5.75 D). At 1 month after retreatment, average deviation from intended correction was 0.08 D; at 3 months it was -0.12 D. Eleven of 12 treated eyes (92%) had uncorrected visual acuity of 20/40 or better and 4 eyes (33%) saw 20/20 or better without correction. Six eyes (50%) were within +/- 0.50 D of intended correction at 3 months. No patients lost any lines of spectacle-corrected visual acuity.

CONCLUSION

Retreatment of residual myopia after LASIK by lifting the flap appears to be effective and associated with minimal complications.

Role of clearance and treatment zones in contrast sensitivity: significance in refractive surgery

PURPOSE

To evaluate the relationship between contrast sensitivity, surgical treatment zone, and clearance (ablation or clear zone-pupil diameter) in photorefractive keratectomy (PRK) and radial keratotomy (RK).

SETTING

Saint Louis University Eye Institute, St. Louis, Missouri, and Hunkeler Eye Center, Kansas City, Missouri, USA.

METHODS

Thirteen patients had PRK and 20, RK. Contrast sensitivity was measured with the Stereo Optical F.A.C.T. (F.A.C.T.) and VectorVision CSV-1000 (VV) charts. Pupils were measured with the Rosenbaum card.

RESULTS

In the PRK group, VV contrast sensitivity at 6 and 12 cycles per degree (cpd) correlated with the ablation zone (r2 = 0.18 and 0.22, respectively), while visual acuity and F.A.C.T. contrast sensitivity did not correlate. In the RK group, both VV and F.A.C.T. contrast sensitivity at 6 cpd correlated with clearance (r2 = 0.29 and 0.12, respectively). Pupils were larger with the VV test than with the F.A.C.T. chart because ambient chart luminance was less in the former.

CONCLUSION

Contrast sensitivity is likely a more sensitive indicator of visual function than acuity in refractive surgery. The VV system unmasks aberrations from the transition zone of ablated and unablated cornea in PRK. Larger samples are needed to determine the critical ablation clearance of the pupil to avoid loss of visual function.

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.

The intrastromal corneal ring segments. Phase II results for the correction of myopia

OBJECTIVE

The purpose of the study was to evaluate the safety and efficacy of the intrastromal corneal ring segments (ICRS) for the correction of myopia.

DESIGN

A 2-year phase II clinical trial of ICRS was initiated in May 1995. The investigational plan specifies that 150 patients with sighted eyes, requiring myopic corrections from -1.00 to -6.00 diopters (D), will each receive ICRS in 1 eye. The patient population will be divided into approximately five patients per ICRS thickness (0.25, 0.30, 0.35, 0.40, and 0.45 mm) per site. Six investigational sites are participating in the trial.

PARTICIPANTS

Fifty-nine men and 43 women requiring myopic corrections were enrolled at four U.S. investigational sites. These 102 patients each received the ICRS product in 1 eye.

INTERVENTION

Correction of myopia.

MAIN OUTCOME MEASURES

Efficacy of ICRS was assessed with respect to the trial endpoints of predictability of refractive effect, uncorrected visual acuity (UCVA), stability of UCVA, maintenance of best spectacle-corrected visual acuity and stability of refractive effect.

RESULTS

As shown by the available month-3 data (99 patients; all device thicknesses), 95 (96%) of 99 patients had a UCVA of 20/40 or better. Ninety-eight (99%) of 99 patients were within 2 lines of their preoperative best spectacle-corrected visual acuity. The average change (with standard error) in cycloplegic refraction (spherical equivalent) achieved by ICRS thickness was -1.27 +/- 0.09 D (0.25 mm), -2.13 +/- 0.16 D (0.30 mm), -2.56 +/- 0.15 D (0.35 mm), -3.77 +/- 0.37 D (0.40 mm) and -4.16 +/- 0.24 D (0.45 mm). Seventy-seven percent (76/99) of the patients were within +/-1.00 D of their intended correction. When the ICRS was removed in two cases, both patients returned to within 0.75 D of their preoperative manifest refraction.

CONCLUSIONS

The ICRS appears to be a viable and effective alternative for the treatment of myopia. Additionally, as indicated by the explant data, the ICRS's refractive effect may be reversible upon removal of the device.

Late onset of corneal scar after excimer laser photorefractive keratectomy

PURPOSE

We studied the occurrence of late scarring after photorefractive keratectomy and its response to topical corticosteroids and debridement during the course of follow-up of 950 eyes that had photorefractive keratectomy with excimer laser.

METHODS

Five eyes of four patients developed localized corneal scars, decreased visual acuity, and increased myopia after five to 33 months of good visual acuity, with trace haze. In two eyes, scars were removed by debridement alone. In these two eyes, recurrent scars were treated by debridement, followed by aggressive treatment with topical corticosteroids. Two other eyes were treated with topical corticosteroids alone. The fifth eye, which developed a scar after debridement to correct a subjective visual distortion after photorefractive keratectomy, was treated with debridement followed by aggressive topical corticosteroids.

RESULTS

Treatment with topical corticosteroids alone in two eyes improved uncorrected visual acuity slightly and decreased myopia, although the scars remained unchanged. Debridement without aggressive topical corticosteroid use resulted in rapid return of the scars and a decrease in visual acuity. Subsequent debridement after aggressive topical corticosteroid treatment resulted in resolution of scars and no recurrence after discontinuation of corticosteroids in one case. In another case, the scar recurred eight months after discontinuation of topical corticosteroids. In Case 4, the scar has not recurred as the topical corticosteroid dosage has been reduced.

CONCLUSIONS

Patients who undergo photorefractive keratectomy should be counseled concerning the risk of late scarring, reexamined frequently after photorefractive keratectomy, and treated with topical corticosteroids after corneal trauma. Long-term treatment with topical corticosteroids may be required to prevent the recurrence of scars after debridement.

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.

Classification of Variable Clinical Response After Photorefractive Keratectomy for Myopia

BACKGROUND

Variation in healing response has been noted after excimer laser photorefractive keratectomy (PRK).

METHODS

A retrospective analysis of 116 eyes that underwent PRK for myopia was performed. Standard surgical protocol and postoperative corticosteroid treatment were followed for all eyes. Scattergrams of achieved correction versus attempted correction at 6 months after surgery were analyzed. Subepithelial corneal haze was compared with refractive outcome.

RESULTS

Three healing responses were observed. Normal responders (84.5%) showed a hyperopic overcorrection at 1 month with a gradual regression toward plano and good refractive outcome. Inadequate responders (11.2%) showed a pronounced early hyperopic overcorrection (greater than 1.50 diopters [D]) with minimal regression at 6 months. Aggressive responders (4.3%) displayed an early overcorrection with rapid regression toward myopia. Clear to trace subepithelial corneal haze was present at 6 months in 96% of normal and inadequate responders. Aggressive responders had more pronounced subepithelial haze at 6 months.

CONCLUSION

Variation in the amount of subepithelial healing response occurs after excimer laser PRK. Abnormal healing responses may be detected early in the postoperative period by correlation of refractive error with the amount of subepithelial haze.

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.