Maylon Hsu

Femtosecond laser-assisted cataract surgery: A current review

To evaluate the safety, efficacy, advantages, and limitations of femtosecond laser-assisted cataract surgery through a review of the literature. A PubMed search was conducted using topic-appropriate keywords to screen and select articles. Initial research has shown appropriate safety and efficacy of femtosecond laser-assisted cataract surgery, with improvements in anterior capsulotomy, phacofragmentation, and corneal incision. Limitations of these studies include small sample size and short-term follow-up. Cost-benefit analysis has not yet been addressed. Preliminary data for femtosecond laser-assisted cataract surgery shows appropriate safety and efficacy, and possible advantage over conventional cataract surgery. Questions to eventually be answered include comparisons of long—term postoperative complication rates—including infection and visual outcomes-and analysis of contraindications and financial feasibility.

A prospective, randomized, fellow eye comparison of WaveLight® Allegretto Wave® Eye-Q versus VISX CustomVue™ STAR S4 IR™ in laser in situ keratomileusis (LASIK): analysis of visual outcomes and higher order aberrations

Purpose To compare outcomes in visual acuity, refractive error, higher-order aberrations (HOAs), contrast sensitivity, and dry eye in patients undergoing laser in situ keratomileusis (LASIK) using wavefront (WF) guided VISX CustomVue and WF optimized WaveLight Allegretto platforms. Methods In this randomized, prospective, single-masked, fellow eye study, LASIK was performed on 44 eyes (22 patients), with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Postoperative outcome measures at 3 months included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, root-mean-square (RMS) value of total and grouped HOAs, contrast sensitivity, and Schirmers testing. Results Mean values for UDVA (logMAR) were −0.067 ± 0.087 and −0.073 ± 0.092 in the WF optimized and WF guided groups, respectively (P = 0.909). UDVA of 20/20 or better was achieved in 91% of eyes undergoing LASIK with both lasers while UDVA of 20/15 or better was achieved in 64% of eyes using the Allegretto platform, and 59% of eyes using VISX CustomVue (P = 1.000). In the WF optimized group, total HOA increased 4% (P = 0.012), coma increased 11% (P = 0.065), and spherical aberration increased 19% (P = 0.214), while trefoil decreased 5% (P = 0.490). In the WF guided group, total HOA RMS decreased 9% (P = 0.126), coma decreased 18% (P = 0.144), spherical aberration decreased 27% (P = 0.713) and trefoil decreased 19% (P = 0.660). One patient lost one line of CDVA secondary to residual irregular astigmatism. Conclusion Both the WaveLight Allegretto and the VISX CustomVue platforms had equal visual and safety outcomes. Most wavefront optimized HOA values trended upward, with a statistically significant increase in total HOA RMS. Eyes treated with the WF guided platform showed a decreasing trend in HOA values.

Double-pass microkeratome technique for ultra-thin graft preparation in Descemet's stripping automated endothelial keratoplasty.

Endothelial keratoplasty is evolving with increased attention placed on the optical qualities of the posterior donor lenticule. In efforts to improve visual outcomes, the effects of the thickness, smoothness, and planar profile are being studied. This paper describes a double-pass microkeratome technique to create ultra-thin (less than 100 μm) Descemet’s stripping automated endothelial keratoplasty grafts.

Management and outcomes of descemet stripping automated endothelial keratoplasty with intraocular lens exchange, aphakia, and anterior chamber intraocular lens.

Purpose: To compare outcomes and complications of Descemet stripping automated endothelial keratoplasty (DSAEK) in complicated cases with intraocular lens (IOL) exchange, aphakia, or anterior chamber intraocular lens (ACIOL) implants with a group of noncomplicated DSAEK cases. Methods: Of the 30 complicated DSAEK cases, 14 eyes underwent concurrent IOL exchange, 5 ACIOLs were not removed, 5 eyes remained aphakic, and 5 eyes had IOL exchange done before or after DSAEK. One eye had an iris-supported phakic IOL removed, followed by cataract extraction with IOL implantation at the time of DSAEK. The comparison group included 109 consecutive DSAEK cases with a history of Fuchs dystrophy or pseudophakic bullous keratopathy. Results: In the complicated group with significant ocular comorbidities, 27.6% achieved best-corrected visual acuity (BCVA) ≥20/40 and 60% had a final BCVA ≥20/70. In the comparison group of patients without visually significant comorbidities, 94.4% of eyes achieved BCVA ≥20/40 with no complication of graft detachments. Of the 30 complicated eyes, 5 (16.7%) had graft detachments and 5 (16.7%) developed IOL dislocations. All grafts remained clear at the last follow-up visit, except 3 cases (10%) in the complicated group, 2 of which were because of primary graft failure and required penetrating keratoplasty. Conclusions: In comparison with uncomplicated DSAEK cases, higher graft and IOL dislocations were observed in cases involving IOL exchanges, ACIOLs, or aphakia.

Prospective, randomized, fellow eye comparison of WaveLight Allegretto Wave Eye-Q versus VISX CustomVueTM STAR S4 IRTM in photorefractive keratectomy: analysis of visual outcomes and higher-order aberrations.

Background The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight® Allegretto platforms. Methods In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy was performed on 46 eyes from 23 patients, with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Three-month postoperative outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive error, root mean square of total and grouped higher-order aberrations, contrast sensitivity, and Schirmer’s testing. Results Mean values for uncorrected distance visual acuity (logMAR) were −0.03 ± 0.07 and −0.06 ± 0.09 in the wavefront-optimized and wavefront-guided groups, respectively (P = 0.121). Uncorrected distance visual acuity of 20/20 or better was achieved in 91% of eyes receiving wavefront-guided photorefractive keratectomy, and 87% of eyes receiving wavefront-optimized photorefractive keratectomy, whereas uncorrected distance visual acuity of 20/15 was achieved in 35% of the wavefront-optimized group and 64% of the wavefront-guided group (P ≥ 0.296). While root mean square of total higher-order aberration, coma, and trefoil tended to increase in the wavefront-optimized group (P = 0.091, P = 0.115, P = 0.459, respectively), only spherical aberration increased significantly (P = 0.014). Similar increases were found in wavefront- guided root mean square of total higher-order aberration (P = 0.113), coma (P = 0.403), trefoil (P = 0.603), and spherical aberration (P = 0.014). There was no significant difference in spherical aberration change when comparing the two platforms. The wavefront-guided group showed an increase in contrast sensitivity at 12 cycles per degree (P = 0.013). Conclusion Both VISX CustomVue and WaveLight Allegretto platforms performed equally in terms of visual acuity, safety, and predictability in photorefractive keratectomy. The wavefront-guided group showed slightly improved contrast sensitivity. Both lasers induced a comparable degree of statistically significant spherical aberration, and tended to increase other higher-order aberration measures as well.

Comparing the rate of regression after conductive keratoplasty with or without prior laser-assisted in situ keratomileusis or photorefractive keratectomy

Purpose: To assess the regression rate of conductive keratoplasty (CK) in patients with or without previous laser-assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). Setting: University of Utah, Medical School, John A. Moran Eye Center, Salt Lake City, Utah. Materials and Methods: A retrospective, age-matched chart review identified records of 6 patients who underwent CK after refractive surgery and 12 patients who underwent CK without prior refractive surgery. The main outcome measures were postoperative uncorrected and corrected visual acuities and refraction changes over time. Results: Preoperatively, the mean manifest refraction spherical equivalent (MRSE) of the 15 eyes (12 patients) that underwent CK without refractive surgery was 0.83 diopters (D) and the 7 eyes (6 patients) that underwent CK after refractive surgery had an average MRSE of 0.27 D. Postoperatively, the mean MRSE of the refractive surgery patients was -0.86 D at 6 months, regressing to -0.67 D at 12 months. The postoperative MRSE in the eyes without refractive surgery was -0.58 D. at 6 months, regressing to -0.38 D at 12 months. The rate of regression was linear in both groups, calculated at 0.033 D per month in all patients. Conclusions: Patients with previous LASIK or PRK showed a greater treatment response to CK but regressed at a similar rate as those eyes without prior LASIK or PRK. Overall CK is a safe procedure that inevitably regresses.

A Comparison of the American Society of Cataract and Refractive Surgery post-myopic LASI K/PRK Intraocular Lens (IOL) calculator and the Ocular MD IOL calculator

Background To compare the average values of the American Society of Cataract and Refractive Surgery (ASCRS) and Ocular MD intraocular lens (IOL) calculators to assess their accuracy in predicting IOL power in patients with prior laser-in-situ keratomileusis (LASIK) or photorefractive keratectomy. Methods In this retrospective study, data from 21 eyes with previous LASIK or photorefractive keratectomy for myopia and subsequent cataract surgery was used in an IOL calculator comparison. The predicted IOL powers of the Ocular MD SRK/T, Ocular MD Haigis, and ASCRS averages were compared. The Ocular MD average (composed of an average of Ocular MD SRK/T and Ocular MD Haigis) and the all calculator average (composed of an average of Ocular MD SRK/T, Ocular MD Haigis, and ASCRS) were also compared. Primary outcome measures were mean arithmetic and absolute IOL prediction error, variance in mean arithmetic IOL prediction error, and the percentage of eyes within ±0.50 and ±1.00 D. Results The Ocular MD SRK/T and Ocular MD Haigis averages produced mean arithmetic IOL prediction errors of 0.57 and −0.61 diopters (D), respectively, which were significantly larger than errors from the ASCRS, Ocular MD, and all calculator averages (0.11, −0.02, and 0.02 D, respectively, all P < 0.05). There was no statistically significant difference between the methods in absolute IOL prediction error, variance, or the percentage of eyes with outcomes within ±0.50 and ±1.00 D. Conclusion The ASCRS average was more accurate in predicting IOL power than the Ocular MD SRK/T and Ocular MD Haigis averages alone. Our methods using combinations of these averages which, when compared with the individual averages, showed a trend of decreased mean arithmetic IOL prediction error, mean absolute upper limit of IOL prediction error, and variance, while increasing the percentage of outcomes within ±0.50 D.

Evaluation of the American Society of Cataract and Refractive Surgery intraocular lens calculator for eyes with prior radial keratotomy.

Background The purpose of this study was to evaluate the American Society of Cataract and Refractive Surgery (ASCRS) intraocular lens (IOL) calculator for eyes with prior radial keratotomy and assess the accuracy of its methods in predicting IOL power in patients with previous radial keratotomy. Methods This retrospective study included data from 15 eyes with previous radial keratotomy and subsequent cataract surgery. The average central power and Humphrey Atlas methods from the ASCRS IOL calculator, along with an average IOL power produced from an average of these two methods (ASCRS average), were compared. Primary outcome measures for each method were mean arithmetic and absolute IOL prediction error, variance in mean arithmetic IOL prediction error, and the percentage of refractive outcomes within ±0.50, ±1.00, ±1.50, and ±2.00 diopters (D). Results The average central power method and the ASCRS average were significantly more accurate than the Humphrey Atlas method in terms of mean absolute IOL prediction error (1.03 D and 1.02 D versus 1.53; P = 0.04 and P = 0.01, respectively). In addition, the average central power method and ASCRS average produced a higher percentage of refractive outcomes within ±0.50 D when compared with the Humphrey Atlas method (60% and 46.67% versus 0%, respectively). A comparison of the average central power method and the ASCRS average demonstrated a smaller variance and higher percentage of patients within ±1.00 D when using the ASCRS average. Conclusion The ASCRS calculator for eyes with prior radial keratotomy is an easily accessible and valuable online tool for calculating IOL power in patients with previous radial keratotomy. We found that the ASCRS average produced by the calculator provided the best IOL prediction. We recommend using it with the addition of 1.00 to 1.50 D to its IOL power prediction.

The Incidence of Central Serous Chorioretinopathy after Photorefractive Keratectomy and Laser In Situ Keratomileusis

Purpose. To assess the incidence of central serous chorioretinopathy (CSCR) following laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Methods. A chart review was performed to identify all patients with CSCR and a previous history of LASIK or PRK. Results. Over the 6-year study period, 1 of 4,876 eyes which had LASIK or PRK at the Moran Eye Center was diagnosed with CSCR. One other patient was referred from an outside center, developed CSCR symptoms one month after PRK. Both patients were managed conservatively with a final visual acuity of 20/20 or better. All other patients presented 4 or more years after refractive surgery. Conclusions. We report the first 2 CSCR cases developing within one month after PRK. The low incidence argues against a causal association. Topical corticosteroids or anxiety may elevate cortisol levels presenting therapeutic challenges for the management of CSCR after PRK or LASIK.

Radial keratotomy associated endothelial degeneration

Purpose To describe the presentation and clinical course of eyes with a history of radial keratotomy (RK) and varying degrees of endothelial degeneration. Methods Retrospective case series were used. Results Thirteen eyes (seven patients) were identified with clinical findings of significant guttata and a prior history of RK. The mean age of presentation for cornea evaluation was 54.3 years (range: 38–72 years), averaging 18.7 years (range: 11–33 years) after RK. The presentation of guttata varied in degree from moderate to severe. Best corrected visual acuity (BCVA) ranged from 20/25 to 20/80. All patients had a history of bilateral RK, except one patient who did not develop any guttata in the eye without prior RK. No patients reported a family history of Fuch’s Dystrophy. One patient underwent a penetrating keratoplasty in one eye and a Descemet’s stripping automated endothelial keratoplasty (DSAEK) in the other eye. Conclusions RK may induce a spectrum of endothelial degeneration. In elderly patients, the findings of guttata may signify comorbid Fuch’s dystrophy in which RK incisions could potentially hasten endothelial decomposition. In these select patients with stable cornea topography and prior RK, DSAEK may successfully treat RK endothelial degeneration.