Comparison of a second-generation trabecular bypass (iStent inject) to ab interno trabeculectomy (Trabectome) by exact matching.

PURPOSE: To achieve a highly balanced comparison of trabecular bypass stenting (IS2, iStent inject) with ab interno trabeculectomy (T, Trabectome) by exact matching. METHODS: Fifty-three IS2 eyes were matched to 3446 T eyes. Patients were matched using exact matching by baseline intraocular pressure (IOP), the number of glaucoma medications, and glaucoma type, and using nearest neighbor matching by age. Individuals without a close match were excluded. All surgeries were combined with phacoemulsification. RESULTS: A total of 78 eyes (39 in each group) could be matched as exact pairs with a baseline IOP of 18.3 ± 5.1 mmHg and glaucoma medications of 2.7 ± 1.2 in each. IOP in IS2 was reduced to 14.6 ± 4.2 mmHg at 3 months and in T to a minimum of 13.1 ± 3.2 mmHg at 1 month. In IS2, IOP began to rise again at 6 months, eventually exceeding baseline. At 24 months, IOP in IS2 was 18.8 ± 9.0 mmHg and in T 14.2 ± 3.5 mmHg. IS2 had a higher average IOP than T at all postoperative visits (p < 0.05 at 1, 12, 18 months). Glaucoma medications decreased to 2.0 ± 1.5 in IS2 and to 1.5 ± 1.4 in T. CONCLUSION: T resulted in a larger and sustained IOP reduction compared with IS2 where a rebound occurred after 6 months to slightly above preoperative values.

Correlation of flow density, as measured using optical coherence tomography angiography, with structural and functional parameters in glaucoma patients.

PURPOSE: To evaluate the correlation between flow density, as measured by optical coherence tomography angiography (OCTA), and structural and functional parameters in patients with open-angle glaucoma. METHODS: Thirty-four eyes of 34 patients with open-angle glaucoma and 35 eyes of 35 healthy subjects were prospectively included in this study. OCTA was performed using RTVue XR Avanti with AngioVue. The macula was imaged with a 3 × 3 mm scan and the optic nerve head (ONH) with a 4.5 × 4.5 mm scan. Visual field parameters [mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI)], Bruch's membrane opening minimal rim width (BMO-MRW), retinal nerve fiber layer thickness (RNFLT) and the stereometric parameters rim area, cup/disc area (HRT III, Heidelberg Retina Tomograph, Heidelberg Engineering) were tested for correlation with flow density data. RESULTS: The flow density (whole en face) in the retinal OCT angiograms (superficial: p = 0.01; deep: p = 0.005), in the radial peripapillary capillary network (p < 0.001) and in the OCT angiograms of the optic nerve head (p = 0.004) were significantly lower in the glaucoma group when compared with the control group. The flow density in the RPC network correlated significantly with all functional and structural parameters tested. The strongest correlation was found between the RPC flow density (inside disc) and the BMO-MRW (Spearman's correlation coefficient = 0.912, p < 0.001). CONCLUSIONS: Glaucoma patients showed a reduced ONH and macular perfusion when compared with healthy controls. The flow density as measured by OCTA correlated with structural damage and visual field loss in glaucoma patients. Non-invasive quantitative analyses of flow density using OCTA provide a new parameter describing a different aspect of glaucoma, which could be useful in clinical practice.

Conjunctival repair after glaucoma drainage device exposure using collagen-glycosaminoglycane matrices.

BACKGROUND: To report the results of the repair of conjunctival erosions resulting from glaucoma drainage device surgery using collagen-glycosaminoglycane matrices (CGM). METHODS: Case series of 8 patients who underwent revision surgery due to conjunctival defects with exposed tubes through necrosis of the overlying scleral flap and conjunctiva after Baerveldt drainage device surgery. The defects were repaired by lateral displacement of the tube towards the sclera, with a slice of a CGM as a patch, covered by adjacent conjunctiva. RESULT: Successful, lasting closure (follow-up of 12 to 42 months) of the conjunctival defects was achieved without any side-effects or complications in all eight cases. CONCLUSIONS: Erosion of the drainage tube, creating buttonholes in the conjunctiva after implantation of glaucoma drainage devices, is a potentially serious problem. It can be managed successfully using a biodegradable CGM as a patch.

[Surgical Options in Glaucoma Management]. / Chirurgische Möglichkeiten der Glaukomtherapie.

During the last few years, there has been a considerable capacity of innovations in glaucoma surgery owing to new micro-stents increasing the aqueous outflow via transscleral routes, via the trabecular meshwork or the suprachoroidal space. These interventions can be easily performed in combination with small-incision cataract surgery. Even the well-known filtering procedures, trabeculectomy and drainage device surgery, formerly perceived as being outdated, re-achieve better reputation owing to refinements in surgical technique and improved surgical experience. Although enthusiasm is understandable, considering the technical advances, we must wait for clinical long-term results and compare the new procedures with the established ones.

SHORT-TERM EFFECTS OF EXERCISE ON OPTIC NERVE AND MACULAR PERFUSION MEASURED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PURPOSE: To evaluate the effects of exercise on optic nerve and macular perfusion using optical coherence tomography angiography. METHODS: Thirteen eyes of 13 healthy volunteers were examined using a high-speed and high-resolution spectral-domain optical coherence tomography XR Avanti with a split-spectrum amplitude-decorrelation angiography algorithm. Blood pressure, heart rate, the mean area of the foveal avascular zone , and flow density on the optic nerve head and macula, before and after exercise were measured and analyzed. RESULTS: Mean patient age was 27.3 ± 3.5 years. Heart rate, systolic and diastolic blood pressure increased significantly after exercise (P < 0.001). The mean area of the foveal avascular zone did not change significantly after exercise (before: 0.27 ± 0.07 mm; after: 0.26 ± 0.07 mm; P = 0.10). The peripapillary and the parafoveal flow density decreased significantly after exercise (peripapillary: before: 65.1 ± 2.1; after: 62.3 ± 3.0; P < 0.001 and parafoveal: before: 56.7 ± 1.3; after: 55.6 ± 1.5; P = 0.007). CONCLUSION: Increased physical activity induced significant changes in optic nerve and macular perfusion, which were measured using split-spectrum amplitude-decorrelation angiography optical coherence tomography angiography. In studies that aim to evaluate optic nerve and macular perfusion using optical coherence tomography angiography, it should be strongly recommended that patients rest before imaging is performed and that data concerning systemic circulation including blood pressure and pulse is included within the evaluation.

Intraocular lens power calculation using standard formulas and ray tracing after DMEK in patients with Fuchs endothelial dystrophy.

BACKGROUND: The study presented here aims to optimize the accuracy of intraocular lens (IOL) power calculations in patients after DMEK by evaluation of the impact of the altered anterior/posterior corneal curvature relationship. METHODS: Scheimpflug-based Oculus Pentacam imaging was performed after DMEK surgery for Fuchs endothelial dystrophy. The IOL power was calculated for all patients by ray tracing, aiming for postoperative emmetropia. We also performed the IOL calculation using four third-generation formulas (SRK-T, Hoffer-Q, Holladay-1 and Haigis). The residual refractions for the individual target IOL were compared and analyzed. RESULTS: This retrospective study included 42 eyes of 33 patients (age 68.73 ± 10.11 years) after DMEK surgery. The differences between the expected residual refraction based on ray tracing and that predicted with the third-generation formulas were statistically significant (all formulas p < 0.001). The highest mean difference in the residual refraction between the target IOL measured by ray tracing and that calculated with third-generation formulas was found for the Haigis formula (0.90 ± 0.40 D), and the lowest mean difference for the SRK/T formula (0.73 ± 0.49 D). CONCLUSIONS: DMEK surgery induced a relevant change in the anterior to posterior corneal curvature relationship; this needs to be taken into account in the IOL power calculation to avoid hyperopic refractive surprises.

Corneal Densitometry as a Novel Technique for Monitoring Amiodarone Therapy.

PURPOSE: The clinical efficacy and toxicity of amiodarone may be determined more effectively by tissue deposition than by levels of the agent in serum. Therefore, corneal densitometry might be useful for therapeutic monitoring. The aim of the study is to evaluate Scheimpflug corneal densitometry in patients with amiodarone keratopathy (AK). DESIGN: Comparative case series. PARTICIPANTS: Sixty-six patients receiving amiodarone therapy and 66 healthy controls were consecutively enrolled in this study. METHODS: Patients were examined using the Oculus Pentacam (Wetzlar, Germany). MAIN OUTCOME MEASURES: Densitometry data from different corneal layers and different annuli were extracted, analyzed, and compared with densitometry values of healthy controls. Duration of treatment, cumulative dose, Orlando stage (slit-lamp biomicroscopy), and serum concentrations of amiodarone and N-desethylamiodarone also were determined, and the correlation to different densitometry data was evaluated. RESULTS: The total corneal light backscatter at total corneal thickness and at total diameter was significantly higher in the amiodarone group compared with the control group (AK group: 28.3±5.2; control group: 24.4±4.2; P < 0.001). Upon dividing the corneal surface into different layers at total thickness, the differences were significant in all layers (P < 0.001). The serum concentrations of the metabolite N-desethylamiodarone correlate with densitometry values, especially in the 0- to 2-mm annulus in the anterior layer (r = 0.419; P = 0.001), whereas the cumulative dose and duration of treatment correlate significantly with the densitometry values in the 0- to 2-mm annulus at total thickness (P = 0.014 and P = 0.022, respectively). CONCLUSIONS: Corneal densitometry is a useful, objective method for quantifying AK and can help in monitoring amiodarone therapy. The serum concentration of the active metabolite N-desethylamiodarone correlates with the extent of keratopathy in the anterior layer, whereas chronic changes in the stroma correlate with the cumulative dose and duration of treatment.

OCT angiography in the mouse: A novel evaluation method for vascular pathologies of the mouse retina.

PURPOSE: To investigate the application of optical coherence tomography (OCT) angiography in the retinas of healthy mice and to evaluate choroidal neovascularization (CNV) in a mouse model of laser-induced CNV. METHODS: C57BL/6J mice aged 18-25 weeks were examined using the spectral-domain optical coherence tomography device RTVue XR Avanti (Optovue, Inc, Fremont, California, USA). Blood flow in different retinal layers was detected using the split-spectrum amplitude-decorrelation angiography algorithm. Fluorescein angiography (FA) images were obtained using the Heidelberg Spectralis device (Heidelberg, Germany). RESULTS: Using the RTVue XR Avanti, we were able to obtain high-quality OCT angiography images of normal vasculature in the superficial, deep capillary and choriocapillary layers in laser-treated mice and untreated controls. Whereas no blood flow was detectable in the outer retina of untreated mice, blood flow and hence neovascular vessels were found in laser-treated mice. CONCLUSIONS: OCT angiography can clearly visualize the normal vascular plexus in the different retinal layers in the mouse retina and choroid. With OCT angiography, it is possible to verify the choroidal neovascularization induced by laser treatment. Thus, OCT angiography is a helpful imaging tool for non-invasive, in vivo evaluation of laser-induced CNV in the mouse.

Optical coherence tomography (OCT) angiography findings in retinal arterial macroaneurysms.

BACKGROUND: Optical coherence tomography angiography is a novel imaging technique that allows dyeless in vivo visualization of the retinal and choroidal vasculature. The purpose of this study was to describe optical coherence tomography (OCT) angiography findings in patients with retinal arterial macroaneurysms (RAMs). METHODS: Three eyes of three patients with RAMs were retrospectively included. Fundus photography, OCT, fluorescein angiography (FA), and OCT angiography were performed. The entire imaging data was analyzed in detail. RESULTS: OCT angiography could detect the RAMs noninvasively without dye injection. By simultaneously observing the OCT scans, it was possible to determine the depth of the RAMs in the retina, to detect the exact localization in relation to the main vessel, and to determine the level of blood flow in the RAMs. CONCLUSIONS: OCT angiography can clearly visualize RAMs without use of a dye. It also allows layer-specific observation of blood flow in each layer of the RAM. OCT angiography provides additional dynamic information on RAMs, which is not obtained with FA and facilitates a better understanding of its morphology and activity. This information in combination with ICG and fluorescein angiography can help to optimize direct laser treatment.

A new surgical triple procedure in pseudoexfoliation glaucoma using cataract surgery, Trabectome, and trabecular aspiration.

BACKGROUND: To evaluate the potential of lowering intraocular pressure in pseudoexfoliation glaucoma with combined phacoemulsification, Trabectome, and trabecular aspiration (triple procedure) compared to phacoemulsification and trabecular aspiration alone. METHODS: Using a case-matched retrospective study design, 30 patients were included into each group. The main outcome measures were the reduction of intraocular pressure and medication score at the end of follow-up. Clinical data were collected from the patients' medical records. RESULTS: Mean follow-up was 15 months in both groups. Intraocular pressure decreased from 25.3 ± 6.3 mmHg to 14.4 ± 3.7 mmHg (p < 0.0001) in the triple procedure group and from 25.3 ± 4.2 mmHg to 18.1 ± 4.2 mmHg (p < 0.0001) in the control group. The medication score was lowered from 3.4 ± 1.7 to 2.1 ± 1.2 (p = 0.0017) in the triple procedure group and from 3.8 ± 1.8 to 2.3 ± 1.5 (p < 0.008) in the control group. The reduction of intraocular pressure was higher (p < 0.004) in the triple procedure group (38.4 ± 17.3 %) compared to the control group (26.8 ± 19.6 %) The reduction of the medication score did not differ significantly. CONCLUSIONS: The triple procedure is more effective in lowering intraocular pressure compared to phacoemulsification and trabecular aspiration alone in pseudoexfoliation glaucoma.

Trabeculectomy using mitomycin C versus an atelocollagen implant: clinical results of a randomized trial and histopathologic findings.

PURPOSE: To assess the efficacy of trabeculectomy with a biodegradable Ologen™ implant (OLO) versus mitomycin C (MMC) in patients in a prospective randomized clinical trial. METHODS: In the MMC group (15 patients), trabeculectomy was performed according to standard protocols. In the OLO group (15 patients) after standard trabeculectomy, the implant was positioned on top of the scleral flap, and no MMC was applied. RESULTS: Mean preoperative intraocular pressure (IOP) levels (OLO: 28.0 ± 9.4; MMC: 23.9 ± 5.0 mm Hg; p = 0.21) and medication score (OLO: 3.4 ± 1.6; MMC: 3.6 ± 1.5; p = 0.56) were comparable in both groups. One year after surgery, the mean IOP was 15.9 ± 4.5 mm Hg in the OLO group (p < 0.01, 43% reduction) and 11.0 ± 2.6 mm Hg in the MMC group (p < 0.01, 54% reduction). The surgical success rate 12 months after surgery was 93.3% in the MMC group and 40% in the OLO group (p = 0.01). CONCLUSIONS: With the atelocollagen-glycosaminoglycan matrix OLO it was not possible to reach the surgical success rate and pressure reduction achieved in the MMC group.

A new rebound tonometer for home monitoring of intraocular pressure.

BACKGROUND: To compare intraocular pressure (IOP) measurements obtained by the Icare ONE rebound tonometer (RTONE) and the Goldmann applanation tonometer (GAT) in healthy persons and glaucoma patients in a prospective study, and to investigate the influence of central corneal thickness (CCT). METHODS: Measurements on 126 right eyes were obtained by three equally skilled ophthalmologists with each of the above-mentioned tonometers. In addition, patients measured their own IOP with the RTONE (RTONE(p)). The means and standard deviation for all tonometers were compared. Agreement between the tonometers was calculated using the Bland-Altman method. RESULTS: A total of 95 (75.3%) patients were able to perform correct self-tonometry. Mean IOPs obtained were 17.1 ± 5.9 mmHg (RTONE performed by ophthalmologist: RTONE (o)), 17.3 ± 5.6 mmHg (RTONE(p)) and 16.5 ± 5.1 mmHg (GAT). Correlation analysis indicated a good correlation between IOP readings obtained using RTONE(o) and RTONE(p) (ρ = 0.916; p < 0.001) and RTONE(o) and GAT (ρ = 0.901; p < 0.001). Bland-Altman analysis revealed a mean difference (bias) between RTONE(o) and RTONE(p), between RTONE(o) and GAT, and between RTONE(p) and GAT of -0.2, 0.6, and 0.8 mmHg, respectively, with 95% limits of agreement of -5.0 to 4.5, -4.4 to 5.6, and -4.6 to 6.1 mmHg, respectively. The difference between RTONE(o) and GAT significantly increased with increasing CCT (ρ = 0.004), with a 10% increase in CCT resulting in a 1.8% increase in the difference. CONCLUSIONS: Measurements obtained with the RTONE, either by an ophthalmologist or by the patient, showed an excellent correlation with those provided by applanation tonometry. RTONE generally tends to overestimate IOP compared to GAT readings and displays a dependence on CCT. This study was registered with the DRKS (German Clinical Trials Register; www.germanctr.de ; DRKS00000478).

Canthaxanthin retinopathy: long-term observations.

PURPOSE: To describe the long-term outcome of canthaxanthin retinopathy. METHODS: We identified 13 patients with small golden particles near the macular region among a group of 35 patients with known consumption of canthaxanthin somewhen between 1983 and 1988. One long-term follow-up examination was possible in 5 of 13 cases after 16-24 years. The examinations included determination of visual acuity, the Amsler grid, slit lamp examination, perimetry, electro-oculography, electroretinography, optical coherence tomography and fluorescein angiography. RESULTS: Complete disappearance of the golden particles took approximately 20 years. The patients in our study were asymptomatic and no functional defect related to canthaxanthin could be detected. CONCLUSIONS: Ingestion of canthaxanthin causes no long-term adverse effects.

Intra-individual comparison after combined phaco-trabecular aspiration in pairs of pseudoexfoliative eyes.

BACKGROUND: Trabecular aspiration is used for combined glaucoma-cataract surgery in coexisting pseudoexfoliation syndrome (XFS) or glaucoma (XFG). Reports on this technique are limited to a few small-scale studies. In this study, we wanted to elucidate whether the result of combined phacoemulsification with trabecular aspiration in the first operated eye is predictive for outcome in the contralateral eye. METHODS: In a retrospective analysis we compared the results from 80 eyes of 40 patients with pseudoexfoliation syndrome or glaucoma, who had undergone bilateral but consecutive phacoemulsification with implantation of a posterior chamber lens combined with trabecular aspiration between 2003 and 2005. RESULTS: The IOP level and medication score after phaco-trabecular aspiration were shown to be significantly lower than the preoperative values after 2 years (p < 0.0001 and p = 0.047). A significant correlation between the first and second eye was detected for reduction of IOP and medication score after 1 year. Kaplan-Meier graphs of the first and second eyes showed an almost parallel trend from 1 day after surgery until 35 months after surgery. CONCLUSIONS: The postoperative outcome in an eye after combined phaco-trabecular aspiration is predictive for the second eye. If this procedure succeeded in the first eye, the prognosis for the same strategy in the fellow eye is also good.

Capsule excision and Ologen implantation for revision after glaucoma drainage device surgery.

BACKGROUND: There is little information available about surgical management after failed glaucoma drainage device (GDD) surgery. We present the outcome of capsule excision after failed GDD surgery compared to capsule excision with additional use of a biodegradable implant (Ologen, version 2) as a placeholder. METHODS: In an observational comparative case series of 19 patients undergoing excision of the GDD capsule, ten prospectively observed consecutive patients were treated by excision of the capsule, topical mitomycin C application, and implantation of an 10 x 10 x 2 mm-sized Ologen implant (group A) while 9 retrospectively observed consecutive patients were treated by excision of the capsule and topical mitomycin C application alone (group B). RESULTS: Mean preoperative IOP was 29.4 mmHg for group A and 27.6 mmHg for group B, while mean postoperative IOP at the last follow-up (mean follow-up 11.2 (group A) and 8.6 (group B) months) was 17.3 mmHg for group A and 19.3 mmHg for group B (p > 0.05). Follow-up of the two groups demonstrated a significant difference in success rate (log-rank test, p = 0.04) in favor of group A. No further pressure-reducing surgery was necessary in any of the patients in group A, but it was needed in three of nine patients in group B. CONCLUSIONS: Although our study has the limitations of small sample size and observational study design, it shows that further investigation is warranted into the potential of Ologen in revision surgery after GDD implantation.

[Application of rebound self-tonometry for measurements in a supine position]. / Einsatzmöglichkeit von Rebound-Selbsttonometrie zur Liegendmessung.

BACKGROUND: Diurnal or nocturnal fluctuations of intraocular pressure (IOP), which are especially common in glaucoma patients, often require hospitalization of the patient in order to be detected. This is often inconvenient for the patient. Therefore, this study evaluated the usefulness of a rebound tonometer (RT) designed for IOP self-tonometry (RT-Home) in an outpatient department, especially in the supine position and out of office hours. METHODS: Over a period of 6 months unselected open-angle glaucoma patients were equipped with a RT-home device for one night each. At the beginning IOP values measured by medical personnel (RT-Home(o)) were compared with IOP measured by the patient (RT-Home(p)), as well as measured by applanation tonometry according to Goldmann (GAT). Patients also completed a questionnaire regarding subjective comfort during use of the RT-Home. RESULTS: The RT-Home(o) showed a bias of -1.1 mm Hg (-7.9 to 5.7 mm Hg) compared to GAT and RT-Home(p) showed a bias of -1.6 mm Hg (-8.9 to 5.9 mm Hg) compared to GAT. The measurement differences between GAT and RT-Home(o) as well as RT-Home(p) showed a stong correlation with the IOP and the central corneal thickness (IOP: r = 0.481, P > 0.0001, RT-Home(o) vs. GAT; corneal thickness: r = 0.612, P < 0.0001, RT-Home(o) vs. GAT). The RT-Home(p) in a supine position showed significantly elevated IOP levels than during the day (P < 0.0001). The RT-Home showed no qualitative differences between measurements in supine and sitting positions. DISCUSSION: The RT-Home is effective and precise for use in an outpatient department to gain a general overview over patients' IOP out of office hours and also in the supine position. In the long term it seems possible that RT-Home can avoid hospitalization for diurnal and nocturnal IOP evaluation especially of young, mobile patients; however, interpretation of the data always requires professional knowledge.

Changes in Anterior, Posterior, and Total Corneal Astigmatism after Descemet Membrane Endothelial Keratoplasty.

Purpose. To evaluate changes in anterior, posterior, and total corneal astigmatism in patients after Descemet membrane endothelial keratoplasty (DMEK). Methods. We retrospectively included 29 eyes of 23 patients (age 67.6 ± 9.8 years, 13 female, 10 male) after DMEK surgery. The magnitude and axis orientation of anterior, posterior, and total corneal astigmatism before and after DMEK were determined using a rotating Scheimpflug system (Pentacam HR, Oculus). Results. The magnitude of anterior, posterior, and total corneal astigmatism in the central cornea did not change significantly after surgery. Before surgery, we found a significant correlation between the magnitudes of anterior and posterior corneal astigmatism (Spearman's correlation coefficient (rS) = 0.526, P = 0.003), while after surgery this correlation was no longer significant (rS = 0.038, P = 0.843). There was a significant correlation between the vector difference between preoperative and postoperative posterior astigmatism and the change in corneal pachymetry (rP = 0.47, P = 0.010). Conclusions. Posterior corneal astigmatism (especially the orientation) and therefore the relationship between anterior and total corneal astigmatism may change after DMEK. This should be considered to improve the accuracy of toric IOL power calculations following phakic DMEK or in combined procedures.

Changes in Corneal Densitometry in Patients with Fuchs Endothelial Dystrophy after Endothelial Keratoplasty.

PURPOSE: The aim of the study was to quantify corneal densitometry in patients with Fuchs endothelial dystrophy (FED) after endothelial keratoplasty. MATERIALS AND METHODS: We retrospectively reviewed the charts and anterior segment data of patients with FED before and after endothelial keratoplasty. Patients were examined using the Scheimpflug-based Oculus Pentacam corneal densitometry module. Densitometry parameters in different corneal layers and in different annuli were extracted and analyzed. RESULTS: 27 eyes of 27 patients after endothelial keratoplasty (11 DSAEK, 16 DMEK) were included. After endothelial keratoplasty the total corneal light backscatter at total corneal thickness in the central cornea (0-2 mm annulus) was significantly lower than before (DSAEK: p = 0.026, DMEK: p = 0.001). In the entire group the total corneal light backscatter at total corneal thickness and at total diameter before surgery correlated with the postoperative values (Pearson correlation = 0.49, p = 0.01). The strongest correlation was found in the central layer in the DMEK group (Pearson correlation = 0.79, p < 0.001). CONCLUSIONS: Corneal densitometry is a useful, objective method for quantification of the outcome of posterior lamellar keratoplasty irrespective of visual acuity. There is a significant correlation between preoperative and postoperative corneal light backscatter values after endothelial keratoplasty, especially in the case of the DMEK procedure.

Changes in Corneal Refractive Power for Patients With Fuchs Endothelial Dystrophy After DMEK.

PURPOSE: To quantify changes in the refractive power of the anterior and posterior corneal surfaces after Descemet membrane endothelial keratoplasty (DMEK) so as to optimize the accuracy of intraocular lens (IOL) power calculations. METHODS: This study included 28 eyes of 21 patients (age 66.6 ± 9.4 years, 11 female, 10 male). Scheimpflug-based Oculus Pentacam imaging was performed before and after DMEK surgery for Fuchs endothelial dystrophy. Corneal power was measured using the K-value of simulated keratometry (SimK) of Pentacam and total corneal refractive power (TCRP) in corneal zones from 1 to 8 mm (SimK 1-8, TCRP1-8). We also analyzed changes in the keratometric power deviation (KPD) and pachymetry. RESULTS: Changes in the SimK in the central cornea were minimal and not significant (SimK 3: before = 43.24 ± 1.33 D; after = 43.01 ± 1.37 D; P = 0.101) but they decreased significantly in the corneal periphery (SimK 4: P = 0.021; SimK 5: P = 0.004; SimK 6: P = 0.002; SimK 7: P = 0.002; SimK 8: P = 0.008). Postoperative TCRP in the central cornea decreased significantly compared with preoperative values (TCRP 3: before = 43.05 ± 1.44 D; after = 41.94 ± 1.34 D; P < 0.001); [TCRP 4: before = 43.16 ± 1.40 (D); after = 41.99 ± 1.27 (D); P < 0.001]. The keratometric power deviation increased significantly after DMEK (before = 0.74 ± 0.45 D; after = 1.40 ± 0.26 D; P < 0.001). CONCLUSIONS: DMEK surgery induced a significant change in the refractive power of the posterior surface of the cornea and thus a decrease in the TCRP of about 1 D, whereas the SimK, which measures only the anterior cornea, remained nearly unchanged. To avoid a hyperopic surprise, it is essential that this TCRP decrease is not overlooked in intraocular lens power calculations.