Postoperative Hyperopic Shift Research Articles

Improving the accuracy of the SRK/T formula in Chinese with implanting less than 10 D IOL calculated by the SRK/T formula: the SRK/T-Li formula.

To explore the accuracy of the improved SRK/T-Li formula in eyes following implantation of intraocular lens (IOL) of less than 10 D as calculated by using the SRK/T formula in Chinese. A total of 489 eyes from 489 patients with cataracts were included in this study. These patients were divided into a training set (271 patients) and a testing set (218 patients). The IOL power calculated by using SRK/T was less than 10 D. We evaluated the accuracy of the modified SRK/T-Li formula (P = PSRK/T × 0.8 + 2 (P = implanted IOL power; PSRK/T = IOL power calculated by SRK/T)). We evaluated the mean absolute error (MAE), percentage of prediction error (PE) within ± 0.25, ± 0.50, and ± 1.00 D, and the percentage of postoperative hyperopia. The MAE values in order of lowest to highest were as follows: 0.412 D (SRK/T-Li), 0.414 D (Barrett Universal II, (BUII)), 0.814 D (SRK/T), and 1.039 D (Holladay 1). The percentage of PE within ± 0.25 D, ± 0.50 D, and ± 1.00 D was 38.99%, 69.27% and 92.66% (BUII), 40.83%, 69.27% and 94.04% (SRK/T-Li), 20.64%, 41.28% and 71.56% (SRK/T), and 7.34%, 16.51% and 53.21% (Holladay 1), respectively. SRK/T-Li had the smallest postoperative hyperopic shift. For Chinese patients with an IOL power of less than 10 D as calculated by using the SRK/T, the SRK/T-Li has good accuracy and is the best choice to reduce postoperative hyperopic shift.

Effect of Lens Vault on the Accuracy of Intraocular Lens Calculation Formulas in Shallow Anterior Chamber Eyes

To explore the impact of preoperative lens vault (LV) on the accuracy of the Barrett Universal Ⅱ, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Kane, and SRK/T formulas in eyes with a shallow anterior chamber. Retrospective case series. Included were 409 eyes with anterior chamber depth (ACD) shallower than 3.0 mm that underwent phacoemulsification. Eyes were divided into a short axial length (AL) group (<22.00 mm) and a normal AL group (22.00 ≤ AL < 24.50 mm). Each group was further divided into a small LV subgroup (LV <0.95 mm) and a large LV subgroup (LV ≥0.95 mm) according to the median of the preoperative LV. Postoperative refraction was measured 3 months after surgery. Mean absolute error (MAE) was calculated and compared for each formula. The correlation between LV and the mean numeric error predicted by each formula was analyzed. Overall, the Barrett and Kane formulas generated the smallest MAE in both short AL and normal AL groups (P < .05 for both). In short AL eyes with small LV, the Haigis formula performed better than other traditional formulas (P < .05 for all). In normal AL eyes with a small LV, the Barrett and Kane formulas showed higher accuracy (P < .05 for all), and other formulas were comparable. In either subgroup with a large LV, the Haigis formula created a significant higher MAE (P < .001 for all), followed by Hoffer QST. Positive correlations were found between LV and mean numeric errors predicted by all formulas, except for Barrett and Kane formulas (P < .001 for all), indicating a postoperative hyperopic shift with an increased LV. In shallow anterior chamber eyes with a large LV, the Haigis and Hoffer QST formulas taking preoperative ACD into calculation surprisingly showed a larger prediction error. However, the Barrett and the Kane formulas, which include both ACD and lens thickness as predictive parameters, showed good accuracy in both small and large LV subgroups. Therefore, although formulas referring to preoperative ACD are generally believed to achieve better refractive results in patients with a shallow anterior chamber, LV may be valuable to consider when choosing an IOL power calculation formula.

Assessing the validity of corneal power estimation using conventional keratometry for intraocular lens power calculation in eyes with Fuch\u2019s dystrophy undergoing Descemet membrane endothelial keratoplasty

PurposeThe present retrospective study was designed to test the hypothesis that the postoperative posterior to preoperative anterior corneal curvature radii (PPPA) ratio in eyes with Fuch’s dystrophy undergoing Descemet membrane endothelial keratoplasty (DMEK) is significantly different to the posterior to anterior corneal curvature radii (PA) ratio in virgin eyes and therefore renders conventional keratometry (K) and the corneal power derived by it invalid for intraocular lens (IOL) power calculation.MethodsMeasurement of corneal parameters was performed using Scheimpflug imaging (Pentacam HR, Oculus, Germany). In 125 eyes with Fuch’s dystrophy undergoing DMEK, a fictitious keratometer index was calculated based on the PPPA ratio. The preoperative and postoperative keratometer indices and PA ratios were also determined. Results were compared to those obtained in a control group consisting of 125 eyes without corneal pathologies. Calculated mean ratios and keratometer indices were then used to convert the anterior corneal radius in each eye before DMEK to postoperative posterior and total corneal power. To assess the most appropriate ratio and keratometer index, predicted and measured powers were compared using Bland-Altman plots.ResultsThe PPPA ratio determined in eyes with Fuch’s dystrophy undergoing DMEK was significantly different (P < 0.001) to the PA ratio in eyes without corneal pathologies. Using the mean PA ratio (0.822) and keratometer index (1.3283), calculated with the control group data to convert the anterior corneal radius before DMEK to power, leads to a significant (P < 0.001) underestimation of postoperative posterior negative corneal power (mean difference (∆ = − 0.14D ± 0.30) and overestimation of total corneal power (∆ = − 0.45D ± 1.08). The lowest prediction errors were found using the geometric mean PPPA ratio (0.806) and corresponding keratometer index (1.3273) to predict the postoperative posterior (∆ = − 0.01 ± 0.30) and total corneal powers (∆ = − 0.32D ± 1.08).ConclusionsCorneal power estimation using conventional K for IOL power calculation is invalid in eyes with Fuch’s dystrophy undergoing DMEK. To avoid an overestimation of corneal power and minimize the risk of a postoperative hyperopic shift, conventional K for IOL power calculation should be adjusted in eyes with Fuch’s dystrophy undergoing cataract surgery combined with DMEK. The fictitious PPPA ratio and keratometer index may guide further IOL power calculation methods to achieve this.

Refractive outcomes following cataract combined with lamellar keratoplasty: femtosecond-DSEK versus microkeratome-DSAEK.

Prediction of postoperative refraction following posterior lamellar keratoplasty is crucial for choosing proper intraocular lens power in combined surgeries. Femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK) creates thin, planar grafts while microkeratome-assisted Descemet's stripping automated endothelial keratoplasty (DSAEK) creates non-planar, concaved grafts. We evaluated whether this fundamental difference affects the refractive outcomes in cataract surgery combined with FS-DSEK compared to cataract surgery combined with microkeratome-assisted DSAEK. A retrospective analysis of 28 patients who underwent FS-DSEK combined with phacoemulsification and intraocular lens (IOL) implantation (group A) compared to 26 patients who underwent microkeratome-assisted DSAEK combined with phacoemulsification and IOL implantation (group B). Pre- and 1-year postoperative best-corrected visual acuity (BCVA), keratometry values, corneal thickness, central-to-peripheral graft thickness ratio (C/P ratio), and target postoperative spherical equivalent (SE) versus actual postoperative SE were analyzed. Target postoperative SE and actual postoperative SE significantly shifted toward hyperopia in group B, but not in group A. Postoperative hyperopic shifts were 0.14D and 1.13D in groups A and B, respectively (P < 0.001). BCVA improved after surgery in both groups, with no significant difference between the groups. Postoperative C/P ratio differed significantly between the groups and was negatively correlated with postoperative hyperopic shift (r = - 0.616, P < 0.001). Refractive outcomes of cataract surgery combined with FS-DSEK are relatively neutral, whereas those of cataract surgery combined with microkeratome-assisted DSAEK cause significant hyperopic shift. Clinicians should select accordingly an appropriate intraocular lens power when performing these surgeries.

An innovative approach for determining the customized refractive index of ectatic corneas in cataractous patients

The aim of this study is to determine the customized refractive index of ectatic corneas and also propose a method for determining the corneal and IOL power in these eyes. Seven eyes with moderate and severe corneal ectatic disorders, which had been under cataract surgery, were included. At least three months after cataract surgery, axial length, cornea, IOL thickness and the distance between IOL from cornea, and aberrometry were measured. All the measured points of the posterior and anterior parts of the cornea converted to points cloud and surface by using the MATLAB and Solidworks software. The implanted IOLs were designed by Zemax software. The ray tracing analysis was performed on the customized eye models, and the corneal refractive index was determined by minimizing the difference between the measured aberrations from the device and resulted aberrations from the simulation. Then, by the use of preoperative corneal images, corneal power was calculated by considering the anterior and posterior parts of the cornea and refractive index of 1.376 and the customized corneal refractive index in different regions and finally it was entered into the IOL power calculation formulas. The corneal power in the 4 mm region and the Barrett formula resulted the prediction error of six eyes within ± 1 diopter. It seems that using the total corneal power along with the Barrett formula can prevent postoperative hyperopic shift, especially in eyes with advanced ectatic disorders.

Using the posterior to anterior corneal curvature radii ratio to minimize the risk of a postoperative hyperopic shift after Descemet membrane endothelial keratoplasty.

To evaluate different corneal parameters in identifying patients at risk of a hyperopic shift after (DMEK). This retrospective study included 92 eyes of patients with FECD after DMEK surgery. Pachymetry parameters, various tomographic parameters and densitometry values before and after DMEK were determined using a rotating Scheimpflug system (Pentacam HR, Oculus). For assessing the posterior to anterior corneal curvature relationship, we calculated the RPA (posterior to anterior corneal curvature radii ratio). The average keratometry reading of the posterior corneal surface (KmB) increased and the total corneal refractive power (TCRP) decreased significantly after surgery (P < .001). There was a significant difference between the preoperative and postoperative RPA (P < .001) and the posterior Q value (P < .001). The strongest correlation was found between the change in the KmB and the preoperative RPA (Spearman's correlation coefficient = 0.872, P < .001). In the receiver operating characteristic (ROC) analysis, the highest AUC values (for ∆KmB) among the different preoperative parameters tested were obtained for RPA and posterior Q value (Asph. QB) with AUROC (area under the ROC) values of 0.95 and 0.89, respectively. The Q value and the RPA showed the highest correlation with the change in corneal refractive power and the greatest AUC. These parameters could be used as surrogate markers to identify eyes that might be at risk of a greater postoperative hyperopic shift, which would allow more accurate setting of refractive goals.

Deep Anterior Lamellar Keratoplasty and Phototherapeutic Keratectomy for Management of Thiel-Behnke Corneal Dystrophy

Background To evaluate the outcome of surgical options in the management of Thiel-Behnke corneal dystrophy (TBCD). This is a retrospective case report. Methods A 52-year-old female with TBCD with a visual acuity of 0.50 LogMAR in both eyes underwent deep anterior lamellar keratoplasty (DALK) in her left eye (LE) and, 8 months later, phototherapeutic keratectomy (PTK) in her right eye (RE). Postoperatively, the presence of recurrence, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), central corneal thickness (CCT), and spherical equivalent (SE) were assessed. Spectralis domain anterior segment optical coherence tomography was also performed to evaluate corneal morphology and reflectivity. Results At 1 year, the LogMAR UCVA and BCVA were +0.80 and +0.24, respectively, in the LE and +0.70 and +0.24 in the RE, respectively. CCT and SE were 741 microns (μm) and +4.25 diopters (D) in the LE, respectively, and 339 μm and +6.00 D in the RE, respectively. The cornea was clear in the LE. There was early recurrence of the TBCD and corneal haze in the RE. Conclusions The visual outcome of both DALK and PTK were similar for TBCD. No episodes of rejection or recurrence of dystrophy were noted in the eye that underwent DALK. However, postoperative hyperopic shift, persistent haze, and early recurrence were noted after PTK.

Changes in Axial Length and Refractive Error After Noninvasive Normalization of Intraocular Pressure From Elevated Levels

To explore the changes in axial length and refractive error after noninvasive normalization of intraocular pressure (IOP) from elevated levels. A prospective observational study. We enrolled 51 consecutive patients with abnormally elevated unilateral IOP (≥10 mm Hg compared with that of the fellow eye, in which the IOP was ≤21 mm Hg). In all patients, the keratometric value and axial length were obtained with the aid of an IOLMaster before and after IOP normalization (defined as attainment of an IOP difference of ≤3 mm Hg compared with the fellow eye, with or without topical application of ocular hypotensive therapy). We focused principally on IOP, axial length, the keratometric value, and the predicted refractive difference (the predicted refractive error after IOP normalization upon placement of an IOL with a power for emmetropia correction determined prior to IOP normalization). The axial length was significantly reduced from 23.5 to 23.3 mm after IOP normalization, from 45.9 mm Hg to 14.3 mm Hg (P < .001). The change in IOP correlated with that of the axial length (r = 0.826, P < .001), but not with the change in the keratometric value (P = .618). The change in axial length per 10 mm Hg IOP decrease was -0.06 mm (P < .001). The IOP change was correlated with the predicted refractive difference (r = 0.693, P < .001); the predicted refractive difference per 10 mm Hg IOP decrease was +0.15 diopter (P < .001). The axial length decreased and the predicted refractive difference increased (hyperopia) as IOP decreased. Therefore, a possible risk of postoperative hyperopic shift should be considered when biometric examination for IOL power calculation is performed in a patient with an abnormally elevated IOP.

Topographic Hot Spot Before Descemet Stripping Automated Endothelial Keratoplasty Is Associated With Postoperative Hyperopic Shift

The aim of this study was to investigate topographic "hot spots" on the anterior corneal surface before Descemet stripping automated endothelial keratoplasty (DSAEK) and their effects on postoperative visual acuity and hyperopic shift. Twenty-seven eyes of 27 patients with bullous keratopathy, who underwent DSAEK were studied. We defined a hot spot as a focal area with relatively high refractive power on the anterior corneal surface in eyes with bullous keratopathy. Refractive spherical equivalent, keratometric value, and corneal topography were retrospectively evaluated using anterior segment optical coherence tomography (AS-OCT). Hot spots were identified in 11 eyes (42.3%) before DSAEK and disappeared in 9 eyes of these eyes (81.8%) at 6 months after DSAEK. AS-OCT revealed focal epithelial thickening in the same areas as the hot spots. There was no significant difference in the postoperative visual acuity between eyes with and without hot spots (P > 0.05). The keratometric value of the anterior corneal surface significantly flattened from 45.7 ± 2.7 diopters (D) before DSAEK to 44.2 ± 2.7 D 1 month after DSAEK in eyes with hot spots (P = 0.01), whereas in eyes without hot spots, there were no significant differences in the keratometric values before and after DSAEK. At 6 months, the refractive change was +1.1 ± 1.3 D in eyes with hot spots and -0.2 ± 0.6 D in eyes without hot spots (P = 0.034). In eyes with focal epithelial thickening, topographic hot spots on the anterior corneal surface were observed using AS-OCT. The hot spots disappeared after DSAEK and had no influence on the postoperative visual acuity.

Postoperative hyperopic shift after cataract surgery in silicone oil‐filled eyes

Vitrectomy with silicone oil (SO) instillation has been widely used in complicated vitreoretinal diseases to achieve retina stability. Because progressive lens opacity is common after vitrectomy and SO infusion, the removal of SO and cataract extraction with intra-ocular lens (IOL) implantation may be performed in the same setting. The refractive outcomes of cataract surgery with simultaneous SO removal have shown acceptable results. However, the refractive outcome after cataract surgery is less predictable in some complicated cases in which intravitreal SO is retained to achieve a long-term tamponade effect. We investigate the refractive outcome of cataract surgery in 21 SO-filled eyes with complicated vitreoretinal diseases and compare the results with those in 42 vitrectomized eyes without SO instillation. The SO used in our study was 5000 centistokes. Axial length (AL) measurements were performed using contact A-scan echography (Sonomed A-2500, New York, NY, USA). To adjust the falsely elongated AL due to the low sound velocity in SO, the following formula was used: AL = anterior chamber depth + lens thickness + vitreous length *0.68. IOL power was calculated using the SRK-T formula. In all SO-filled eyes, we generally chose a more myopic calculated target refraction when deciding the IOL power to compensate for the possible hyperopic shift due to a higher refractive index of SO (Stefansson et al. 1988; Smith et al. 1990; Hotta & Sugitani 2005). Foldable acrylic IOLs (AcrySof SA60AT for power ≧6 D or AcrySof MA60MA for power<6 D; Alcon Surgery) were implanted into the capsular bag in all eyes. Intergroup comparison was shown in Table 1. The refractive outcomes in the SO-filled group were more variable (1.07 ± 2.26 D versus −0.57 ± 1.15 D) and showed a significant tendency of hyperopic shift (+2.89 ± 2.15 D versus + 0.04 ± 1.0 D, p < 0.001). Eyes in the SO-filled group had a higher proportion of cases undergoing scleral buckling procedure, a shorter anterior chamber depth (ACD) and a longer adjusted AL in average. In one eye in the SO-filled group, the refraction changed from +3.25 D after cataract surgery to 0 D after SO removal 3 years later. The uncertainty of postoperative refraction after cataract surgery in SO-filled eyes is due to several perioperative factors. In our study, the SO-filled group had significantly longer average AL and shorter average ACD, which might be related to a higher rate of scleral buckling procedure performed in those eyes. A longer AL could augment the SO-induced acoustic signal attenuating effect and make the measurement less reliable (Ghoraba et al. 2002). Previous studies found that a hyperopic shift in refraction would be induced when vitreous was replaced with SO through vitrectomy in phakic or pseudophakic eyes (Stefansson et al. 1988; Smith et al. 1990; Hotta & Sugitani 2005). This tendency of SO-induced hyperopic shift was also noted in our study. However, the amount of hyperopic shift showed great variation among different studies. The posterior convex curvature of the IOL is thought to be related to the amount of hyperopic shift (Hotta & Sugitani 2005). Incomplete SO filling in the vitreous cavity causing changes in curvature and contact area of SO-fluid interface in different head positions may also result in variability in refractions and AL measurement (Dick et al. 1997). In conclusion, the refractive results of cataract surgery in SO-filled eyes were generally more variable than in simply vitrectomized eyes. Because a mean hyperopic shift is about 3.0 D in our study, we suggest choosing −2.5 to − 3.0 D target refraction, which may partially compensate for the SO-induced hyperopic shift, if SO is intended to be left for a long-term tamponade effect.

L’intervention combinée greffe-cataracte

Corneal pathologies leading to keratoplasty are often associated with cataract and combined surgery is therefore mandatory. Triple procedure with penetrating keratoplasty and concurrent cataract extraction followed by intra ocular lens (IOL) implantation is usually the preferential choice because visual rehabilitation is theoretically more rapid. Surgeons have to be aware of surgical conditions during open-sky surgery because vitreous pressure is not counterbalanced by anterior chamber pressure. Today, many surgeons prefer non-simultaneous procedures with cataract surgery performed months after grafting because of the improvement in spherical refractive error. More recently, new triple procedures, Descemet's stripping automated keratoplasty and concurrent cataract surgery have gained popularity, especially in patients with Fuchs dystrophy associated with cataract. Surgery starts with phacoemulsification, followed by endothelium exchange through a 3 to 5 mm incision. Advantages against classic triple procedure are quick visual rehabilitation, fewer induced refractive errors, minimal postoperative discomfort and corneal integrity. Surgeons have to consider an eventual postoperative hyperopic shift secondary to corneal lenticule shape when choosing adequate intraocular lens.

Femtosecond Laser Refractive Surgery after Descemet Stripping-Automated Endothelial Keratoplasty

Purpose. To report the use of femtosecond laser-assisted in situ keratomileusis (LASIK) in the treatment of hyperopia subsequent to Descemet stripping-automated endothelial keratoplasty (DSAEK). Methods. Interventional case report. Results. A 66-year-old woman with Fuchs endothelial dystrophy developed bullous keratopathy after cataract surgery in her right eye. She underwent DSAEK with a significant postoperative hyperopic shift in her refraction. Thirteen months after DSAEK, she underwent wavefront-guided, femtosecond laser-assisted LASIK (IntraLase, Inc., Irvine, CA/AMO, Inc., IL, USA). Pretreatment unaided visual acuity was 20/120, and best-corrected visual acuity was 20/20 with a refraction of +3.25/−0.50 × 170. One year after laser refractive correction, unaided visual acuity was 20/20 with a refraction of +0.25/−0.75 × 160. Conclusion. To our knowledge, this is the first paper on the successful treatment of hyperopic shift related to DSAEK with wavefront-guided, femtosecond laser-assisted LASIK.

Analysis of posterior donor corneal parameters 1 year after Descemet stripping automated endothelial keratoplasty (DSAEK) triple procedure

Although Descemet stripping automated endothelial keratoplasty (DSAEK) was demonstrated to be effective for the treatment of endothelial corneal diseases, a variable hyperopic shift has been measured as a common occurrence postoperatively. The aim of this work was to investigate the variance in the corneal and refractive responses to DSAEK combined with phacoemulsification and implantation of intra-ocular lens (IOL), namely the DSAEK triple procedure. The refractive, topographic, and anterior segment optical coherence tomography (AS-OCT) data of 23 eyes treated with DSAEK triple procedure were analyzed. A mean refractive IOL target of -1.04 +/- 0.09 D was calculated based on empirical data of our early experience to achieve emmetropia in all the eyes included in the study. Donor corneal parameters, i.e., graft diameter, thickness, and profile, were investigated in order to verify their possible role in the variable refractive shift after DSAEK. Although the 1-year mean refractive outcome was close to emmetropia (-0.01 +/- 0.89 D), the average difference between the targeted postoperative refraction and the 1-year postoperative spherical equivalent refraction was +0.98 +/- 0.87 D. Correlations of refractive change with central graft thickness (r = 0.36, p = 0.05) and graft diameter (r = 0.45; p = 0.03) were statistically significant. AS-OCT analysis revealed how the graft shape, with graft thicker in the periphery compared with the center, contributed to reduce the radius of curvature of the posterior cornea, thus favoring the hyperopic shift postoperatively. DSAEK triple procedure provides negligible changes in the surface topography, however with a variable amount of hyperopic shift postoperatively. Central graft thickness and graft profile together contributed to approximately two-thirds of the variance in refractive shift postoperatively. Lenticule diameter provided a minor influence on postoperative hyperopic shift than other graft parameters.

Descemet Stripping Automated Endothelial Keratoplasty Tissue Preparation With Femtosecond Laser and Contact Lens

To report a novel method of preparing planar Descemet stripping automated endothelial keratoplasty (DSAEK) tissue using a femtosecond laser with a hyperopic soft contact lens (Hyp-SCL). DSAEK tissue was prepared from 11 cadaveric porcine eyes. A femtosecond laser was used to create 400-microm flaps, with or without a Hyp-SCL, after which the eyes were imaged with anterior segment optical coherence tomography. The ratio of the mean central thickness (C) to the mean peripheral thickness (P) was calculated using the flap tool. Eleven eyes were cut (5 without, 5 with, and 1 without and with a Hyp-SCL). In all corneas, the cut interfaces were visualized by anterior segment optical coherence tomography. The mean C:P ratio of the flap made without a Hyp-SCL was 0.998 (range 0.968-1.03, SD = 0.254) compared with 0.904 (range 0.851-0.985, SD = 0.509) with a Hyp-SCL (P = 0.001), demonstrating that a cut made with a Hyp-SCL created a flap that was significantly more concave than that created without a Hyp-SCL, resulting in a more planar DSAEK graft. However, the C:P ratios calculated for DSAEK tissue made without (mean 0.998, range 0.965-1.02, SD = 0.0195) and with (mean 1.02, range 0.986-1.05, SD = 0.0250) a Hyp-SCL did not show significance (P = 0.07). Combining a femtosecond laser and a Hyp-SCL may aid in the creation of planar donor tissue for DSAEK. Clinically, this could reduce the amount of postoperative hyperopic shift, although further human corneal studies are warranted.

Early phototherapeutic keratectomy for basement membrane dystrophy after laser in situ keratomileusis

Phototherapeutic keratectomy (PTK) was performed to treat preexisting silent epithelial basal membrane dystrophy 1 month after laser in situ keratomileusis in 2 patients (4 eyes). The symptoms resolved dramatically during the follow-up period, with the patients reporting an immediate subjective visual improvement. At the last follow-up visit, 3 months after PTK, the eyes were asymptomatic, the epithelium was regular, no corneal erosions recurred, and the visual acuity was normal with no fluctuations. No eye developed haze greater than grade 1. There was no postoperative hyperopic shift, and no eye lost lines of best spectacle-corrected visual acuity.

Corneal profile analysis after Descemet stripping endothelial keratoplasty and its relationship to postoperative hyperopic shift

To evaluate changes in the corneal profile after Descemet stripping endothelial keratoplasty (DSEK) using anterior segment optical coherence tomography (AS-OCT) analysis and to describe its relationship to a dynamic postoperative hyperopic shift. John A. Moran Eye Center, University of Utah, Salt Lake City, USA. In this retrospective observational study, 9 eyes had DSEK and were followed with manifest refractions and AS-OCT analysis. To assess changes in the thickness of the cornea, measurements for each AS-OCT image were taken at the vertex of the cornea, at 1.5 mm on each side of the vertex, and at the distal edges of the graft. Patients were followed for a mean of 134 days (range 46 to 228 days). Monthly Graft thinning rates were 5.2 microm per month at the vertex, 7.9 microm per month 1.5 mm from the vertex, and 26 microm per month at the edges, with the edges thinning significantly faster than the cornea vertex (P = .0024) and the points on either side of the 3.0 mm visual axis (P = .0018). The mean spherical equivalent (SE) showed an initial hyperopic shift that decreased over the ensuing 100 to 200 days postoperatively. The mean monthly postoperative SE change was -0.25 diopter (D) with a mean preoperative to postoperative SE change of +1.26 D. The donor graft underwent changes after DSEK, which may account for the induced hyperopia and its diminishment over time via changes in the posterior corneal curvature. Results suggest that intraocular lenses be targeted to -1.00 to -1.25 D of myopia for combined DSEK and cataract procedures.

Artisan iris-fixated toric phakic and aphakic intraocular lens implantation for the correction of astigmatic refractive error after radial keratotomy

We report 2 patients who had radial keratotomy (RK) to correct myopia. The first patient developed a postoperative hyperopic shift and cataract. Nine years post RK, she had intracapsular cataract extraction and implantation of an Artisan aphakic intraocular lens (IOL). Twenty years post RK, hyperopia and astigmatism progressed to +7.0 -5.75 x 100 with a best corrected visual acuity (BCVA) of 20/20. Due to contact lens intolerance, the Artisan aphakic IOL was exchanged for an Artisan toric aphakic IOL. Three months later, the BCVA was 20/20 with +1.0 -0.50 x 130. The second patient demonstrated residual myopic astigmatism 6 years after bilateral RK and had become contact-lens intolerant. An Artisan toric phakic IOL was implanted in both eyes. Four months later, the BCVA was 20/25 with a refraction of +0.25 -1.0 x 135 and 20/20 with a refraction of -1.0 x 40. Both patients were satisfied with the visual outcomes.