Clinical outcomes of the light adjustable lens in eyes with a history of prior corneal refractive surgery

PURPOSE

This study aimed to evaluate the visual and refractive outcomes in eyes with a history of laser corneal refractive surgery implanted with the second-generation light-adjustable lens (LAL).

SETTING

Private Practice, Sioux Falls, South Dakota, US.

DESIGN

Retrospective, consecutive case series.

METHODS

Eyes with a history of prior corneal refractive surgery that underwent cataract surgery with implantation of the LAL and were targeted for plano were included. Data on the type and number of prior refractive surgeries were collected, in addition to the timing and number of postoperative adjustments. The primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and the percentage (%) of eyes within ±0.25 diopter (D), ±0.50D, and ±1.00 D of their refractive target.

RESULTS

76 eyes from 70 patients were included. A total of 45 eyes with a history of one prior refractive surgery and 31 eyes with a history of ≥2 refractive surgeries were included. 74% (n=56) of all eyes achieved UDVA of 20/20 or better, 88% (n=67) achieved 20/25 UDVA or better and 93% (n=71) were correctable to 20/20 or better postoperatively. For refractive outcomes, 66% of eyes (n=50) were within ±0.25 D and 86% (n=65) were within ±0.50 D of refractive target.

CONCLUSIONS

Patients with a history of laser corneal refractive surgery achieved favorable visual and refractive outcomes with the LAL. This intraocular lens (IOL), which affords postoperative adjustability, is a promising option for patients with a history of corneal refractive surgery who maintain high expectations for functional uncorrected acuity following cataract surgery.

Sensitivity and specificity of SS-OCT for detecting macular pathologies vs SD-OCT

PURPOSE

To evaluate the sensitivity and specificity of swept-source optical coherence tomography (SS-OCT) biometer compared with the gold standard spectral-domain optical coherence tomography (SD-OCT) for detecting macular pathology in patients with cataract.

SETTING

Eye Centers of Tennessee, Crossville, TN.

DESIGN

Prospective, cross-sectional, observational, examiner-masked.

METHODS

The study included 132 participants aged 50 years and older, who underwent precataract surgery work-up. All participants underwent fixation check retinal scans using SS-OCT biometer (IOLMaster 700) as well as full macular scans using Cirrus SD-OCT. 3 independent masked examiners evaluated the scans if they were normal or had a suspected pathology. Different measures of diagnostic accuracy were calculated for 3 examiners.

RESULTS

True positive rate (sensitivity) ranged from 71.1% (32/45) to 79.2% (42/53), and false negative rate was between 20.8% (11/53) and 28.9% (13/45) for the 3 examiners. True negative rate (specificity) ranged from 86.8% (59/68) to 94.1% (64/68), and false positive rate was between 5.9 (4/68) and 13.2% (9/68). The fitted receiver operating characteristic area ranged from 0.83 to 0.95.

CONCLUSIONS

Using retinal SS-OCT biometer scans as a replacement of the dedicated macular SD-OCT for screening or diagnosing macular health would not be appropriate because of its low sensitivity. SS-OCT biometer may potentially fail to identify approximately one-fourth of patients who actually have the disease. Therefore, the final decision on macular health should be based on the gold standard SD-OCT scans. When full macular SD-OCT scans are not accessible, the limited retinal scan information from SS-OCT biometer may still provide useful insights into the macular health.

Travoprost Intracameral Implant for Open-Angle Glaucoma or Ocular Hypertension: 12-Month Results of a Randomized, Double-Masked Trial

INTRODUCTION

This prospective, multicenter, randomized, double-masked pivotal phase 3 trial evaluated the efficacy and safety of the travoprost intracameral SE-implant (slow-eluting implant, the intended commercial product) and FE-implant (fast-eluting implant, included primarily for masking purposes) compared to twice-daily (BID) timolol ophthalmic solution, 0.5% in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).

METHODS

The trial enrolled adult patients with OAG or OHT with an unmedicated mean diurnal intraocular pressure (IOP) of ≥ 21 and unmedicated IOP ≤ 36 mmHg at each diurnal timepoint (8 A.M., 10 A.M., and 4 P.M.) at baseline. The eligible eye of each patient was administered an SE-implant, an FE-implant or had a sham administration procedure. Patients who received an implant were provided placebo eye drops to be administered BID and patients who had the sham procedure were provided timolol eye drops to be administered BID. The primary efficacy endpoint, for which the study was powered, was mean change from baseline IOP at 8 A.M. and 10 A.M. at day 10, week 6, and month 3. Non-inferiority was achieved if the upper 95% confidence interval (CI) on the difference in IOP change from baseline (implant minus timolol) was < 1.5 mmHg at all six timepoints and < 1 mmHg at three or more timepoints. The key secondary endpoint was mean change from baseline IOP at 8 A.M. and 10 A.M. at month 12. Non-inferiority at month 12 was achieved if the upper 95% CI was < 1.5 mmHg at both timepoints. Safety outcomes included treatment-emergent adverse events (TEAEs) and ophthalmic assessments.

RESULTS

A total of 590 patients were enrolled at 45 sites and randomized to one of three treatment groups: 197 SE-implant (the intended commercial product), 200 FE-implant, and 193 timolol. The SE-implant was non-inferior to timolol eye drops in IOP lowering over the first 3 months, and was also non-inferior to timolol at months 6, 9, and 12. The FE-implant was non-inferior to timolol over the first 3 months, and also at months 6 and 9. Of those patients who were on glaucoma medication at screening, a significantly greater proportion of patients in the SE- and FE-implant groups (83.5% and 78.7%, respectively) compared to the timolol group (23.9%) were on fewer topical glaucoma medications at month 12 compared to screening (P < 0.0001, chi-square test). TEAEs, mostly mild, were reported in the study eyes of 39.5% of patients in the SE-implant group, 34.0% of patients in the FE-implant group and 20.1% of patients in the timolol group.

CONCLUSIONS

The SE-travoprost intracameral implant demonstrated non-inferiority to timolol over 12 months whereas the FE-implant demonstrated non-inferiority over 9 months. Both implant models were safe and effective in IOP lowering in patients with OAG or OHT.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03519386.

Phase 3 Randomized Clinical Trial of the Safety and Efficacy of Travoprost Intraocular Implant in Patients with Open-Angle Glaucoma or Ocular Hypertension

PURPOSE

Evaluate the safety and intraocular pressure (IOP)-lowering efficacy of two models of the travoprost intraocular implant (fast-eluting [FE-implant] and slow eluting [SE-implant]) from one of two pivotal trials (GC-010).

DESIGN

Phase 3, multicenter, randomized, double-masked, sham-controlled, non-inferiority trial.

PARTICIPANTS

Subjects with open-angle glaucoma or ocular hypertension, using 0 to 3 IOP-lowering medications at screening and having an unmedicated baseline mean diurnal IOP (average of 8AM, 10AM and 4PM timepoints) of ≥ 21 mmHg, and an unmedicated baseline IOP of ≤ 36 mmHg at each timepoint in the study eye.

METHODS

Study eyes were randomized to the travoprost intraocular implant (FE-implant [n=200] or SE-implant [n=197] model) plus twice-daily (BID) placebo eye drops, or to sham procedure plus timolol ophthalmic solution, 0.5% BID (n=193).

MAIN OUTCOME MEASURES

The primary outcome was mean change from baseline IOP in the study eye at 8AM and 10AM, at each of day 10, week 6, and month 3. Safety outcomes included adverse events (AEs), corneal endothelial cell counts, visual acuity, and conjunctival hyperemia assessment.

RESULTS

Mean IOP reduction from baseline over the 6 timepoints ranged from 6.6 to 8.4 mmHg for the FE-implant group, from 6.6 to 8.5 mmHg for the SE-implant group, and from 6.5 to 7.7 mmHg for the timolol group. The primary efficacy endpoint was met; the upper limit of the 95% confidence interval of the difference between the implant groups and the timolol group was < 1 mmHg at all 6 timepoints. Study eye AEs, most of mild or moderate severity, were reported in 21.5%, 27.2% and 10.8% of subjects in the FE-implant, SE-implant and timolol groups, respectively. The most common AEs included iritis (FE-implant, 0.5%; SE-implant, 5.1%), ocular hyperaemia (FE-implant, 3.0%; SE-implant, 2.6%), visual acuity reduced (FE-implant, 1.0%; SE-implant, 4.1%; timolol, 0.5%), and IOP increased (FE-implant, 3.5%; SE-implant, 2.6%; timolol, 2.1%). There was one serious study eye AE (endophthalmitis).

CONCLUSIONS

The travoprost intraocular implant demonstrated robust IOP reduction over the 3-month primary efficacy evaluation period following a single administration. The IOP-lowering efficacy of both implant groups was statistically and clinically non-inferior to the timolol group, with a favorable safety profile.

Efficacy and Safety of the Travoprost Intraocular Implant in Reducing Topical IOP-Lowering Medication Burden in Patients with Open-Angle Glaucoma or Ocular Hypertension

PURPOSE

A randomized, double-masked, multicenter, phase 2 trial to evaluate the long-term safety and efficacy of travoprost intraocular implant, an extended-release drug delivery system designed to provide uninterrupted sustained intraocular pressure (IOP)-lowering therapy, thereby reducing patient treatment burden and improving adherence with IOP-lowering medication.

METHODS

Patients with open-angle glaucoma or ocular hypertension were administered a fast-eluting implant (FE implant, n = 51) and received twice-daily (BID) placebo eye drops, a slow-eluting (SE implant, n = 54) and received BID placebo eye drops, or underwent a sham surgical procedure and received BID timolol 0.5% (n = 49). IOP was measured at baseline, day 1-2, day 10, week 4, week 6, month 3, and every 3 months thereafter through 36 months. Efficacy was evaluated by mean change from 8:00 AM unmedicated baseline IOP through month 36, and the percentage of patients receiving the same or fewer topical IOP-lowering medications as at screening (pre-study). Safety was evaluated by adverse events and ophthalmic parameters.

RESULTS

Clinically and statistically relevant IOP-lowering treatment effects were observed through month 36 after a single administration of the travoprost implant compared with BID timolol with mean IOP reductions ranging from 7.6 to 8.8 mmHg for the FE implant group, from 7.3 to 8.0 mmHg for the SE implant group, and from 7.3 to 7.9 for the timolol group at the 8:00 AM timepoint (P < 0.0001 for all treatment groups at all visits). At months 12, 24, and 36, a greater percentage of FE and SE implant patients versus timolol patients were well controlled on the same or fewer topical IOP-lowering medications compared with screening with 63 and 69% for the FE and SE implants groups, respectively, versus 45% for the timolol group at month 36. The safety profile of the implant was favorable; there were no dislodgements, no explantations, no adverse events of conjunctival hyperemia or periorbital fat atrophy, no discontinuations due to study eye adverse events, nor any serious adverse events in the study eye. Comparable changes from baseline in corneal endothelial cell counts were observed in the three treatment groups over the 36 months.

CONCLUSION

The travoprost intraocular implant demonstrated robust IOP-lowering and substantially reduced topical IOP-lowering medication burden for up to 36 months following a single administration, while maintaining a favorable safety profile. The travoprost intraocular implant promises to be a meaningful addition to the interventional glaucoma armamentarium by addressing the key shortcomings of topical IOP-lowering medications, including low adherence and topical side effects while controlling IOP for up to 36 months.

TRIAL REGISTRY

ClinicalTrials.gov identifier NCT02754596 registered 28 April 2016.

The Novel Optical Design and Clinical Classification of a Wavefront-Shaping Presbyopia-Correcting Intraocular Lens

Purpose

To evaluate the clinical rationale of wavefront-shaping technology, describe how intraocular lenses (IOLs) using wavefront-shaping technology are differentiated from refractive or diffractive optical presbyopia-correcting designs, and describe the mode of action of this technology.

Methods

Extended depth of focus (EDoF) IOLs are the latest class of presbyopia-correcting IOLs addressing the growing demand of patients for reduced spectacle dependence. These use various optical technologies, including diffractive designs (eg, TECNIS Symfony ZXR00 and AT LARA 29 MP) and non-diffractive designs such as small aperture (eg, IC-8 IOL and XtraFocus Pinhole Implant), spherical aberration (eg, MINI WELL Ready and LuxSmart), and wavefront shaping (eg, AcrySof IQ Vivity DFT015 and Clareon Vivity CNWET0). Despite some improvement in visual acuity at intermediate and near distances, these technologies can still be associated with increased rate of visual disturbances or poorer distance vision compared with monofocal IOLs. One way to overcome such limitations is using a wavefront-shaping optical principle.

Results

Clinical data show that wavefront-shaping technology results in a continuous EDoF compared with a monofocal IOL while exhibiting a minimal halo, similar to an aspheric monofocal IOL. Clinically, this translates to a lens that has proven to exceed the American National Standards Institute/American Academy of Ophthalmology criteria for an EDoF IOL.

Conclusion

The novel wavefront-shaping optic technology allows patients to achieve a continuous range of vision from distance to functional near with low levels of visual disturbances comparable with aspheric monofocal IOLs.

Surgical outcomes of excisional goniotomy using the kahook dual blade in severe and refractory glaucoma: 12-month results

OBJECTIVES

To describe the efficacy and safety of goniotomy with trabecular meshwork excision using the Kahook Dual Blade (KDB, New World Medical Inc., Rancho Cucamonga, CA) in patients with severe or refractory glaucoma.

METHODS

This retrospective multicentre case series reports on 40 eyes with severe or refractory open-angle glaucoma that underwent standalone or combined KDB goniotomy and were followed for 12 months post-operatively in the United-States, Mexico and Switzerland. Surgical success was defined as an intraocular pressure (IOP) reduction ≥20% from baseline at 12 months, with fewer medications than preoperatively. Mean IOP and antiglaucoma medication reduction, probabilities of achieving an IOP ≤16 or 18 mmHg, and adverse events were also analysed.

RESULTS

Mean IOP decreased from 18.1 ± 5.0 mmHg at baseline to 14.8 ± 3.7 mmHg at 12 months (18.2% reduction, P < 0.001). Concomitantly, the mean number of glaucoma medications decreased from 2.5 ± 1.4 to 1.7 ± 1.2 (32% reduction, P = 0.002). The proportion of eyes achieving an IOP reduction of more than 20% from baseline was 37.5% (n = 15) at 12 months. At 12 months, 67.5% and 82.5% achieved a medicated IOP ≤ 16 and ≤18 mmHg, respectively. No severe complications were reported.

CONCLUSION

Excisional goniotomy with KDB achieves a statistically significant IOP and antiglaucoma medication reduction in severe or refractory glaucoma over a period of 12 months. While its efficacy decreases with time, its favourable safety profile makes it a potentially useful primary or adjunctive procedure in high-risk eyes.

The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study

Purpose

The purpose of this study was to evaluate the effects of negative periocular pressure (NPP), and concomitant intraocular pressure (IOP) lowering, on the biomechanics of the optic nerve head (ONH) and cornea.

Methods

We developed a validated finite element (FE) model of the eye to compute tissue biomechanical strains induced in response to NPP delivered using the Multi-Pressure Dial (MPD) system. The model was informed by clinical measurements of IOP lowering and was based on published tissue properties. We also conducted sensitivity analyses by changing pressure loads and tissue properties.

Results

Application of -7.9 mmHg NPP decreased strain magnitudes in the ONH by c. 50% whereas increasing corneal strain magnitudes by c. 25%. Comparatively, a similar increase in corneal strain was predicted to occur due to an increase in IOP of 4 mmHg. Sensitivity studies indicated that NPP lowers strain in the ONH by reducing IOP and that these effects persisted over a range of tissue stiffnesses and spatial distributions of NPP.

Conclusions

NPP is predicted to considerably decrease ONH strain magnitudes. It also increases corneal strain but to an extent expected to be clinically insignificant. Thus, using NPP to lower IOP and hence decrease ONH mechanical strain is likely biomechanically beneficial for patients with glaucoma.

Translational Relevance

This study provides the first description of how NPP affects ONH biomechanics and explains the underlying mechanism of ONH strain reduction. It complements current empirical knowledge about the MPD system and guides future studies of NPP as a treatment for glaucoma.

Evaluating the safety and efficacy of epi-off corneal cross-linking in patients with thin corneas due to keratectasia

Background

Corneal cross-linking (CXL) is a safe and effective procedure for slowing keratectasia progression in eyes with a corneal thickness of at least 400 µm. Limited research has evaluated the safety and efficacy of epi-off CXL in corneas thinner than 400 µm.

Objective

To evaluate the safety and efficacy of CXL to slow keratectasia progression in eyes with <400 µm preoperative corneal thickness.

Design

Retrospective chart review.

Methods

This retrospective chart review included 37 eyes who underwent epi-off, iso-osmolar riboflavin corneal CXL with a preoperative thinnest point of the cornea <400 µm and had at least 6-12 months of follow-up. Preoperative and postoperative uncorrected visual acuity, best-corrected visual acuity (BCVA), thinnest point of the cornea, flat keratometry, steep keratometry, maximum keratometry (Kmax), need for penetrating keratoplasty, and cases of endothelial failure were recorded. Data were collected at baseline and months 3, 6, 9, and 12 post-CXL.

Results

Following cross-linking, 18 eyes (47%) had improved BCVA, 13 (35%) had an unchanged BCVA, and 6 eyes (16%) had a worse BCVA (p = 0.05). The mean postoperative BCVA was 20/81 (0.61 LogMAR) compared to 20/121 (0.78 LogMAR) preoperatively (p = 0.06). Kmax decreased an average of 1.1 D at 3-month (p = 0.53) and 3.4 D at the furthest follow-up (p = 0.10). At the farthest follow-up, 22.7% of eyes had >1 D of Kmax steepening. No patients required keratoplasty and there were no cases of endothelial failure in the follow-up period.

Conclusion

This research supports the safety and efficacy of epi-off, iso-osmolar CXL in eyes with <400 μm baseline corneal thickness with no patients requiring penetrating or endothelial keratoplasty, a trend toward improvement in BCVA, and Kmax flattening. In the future, prospective studies would be helpful to confirm these findings.

Defocus Curve of Emerging Presbyopic Patients

Purpose

To create a defocus curve of emerging presbyopic patients of various age groups.

Setting

Single site private practice in Sioux Falls, South Dakota.

Design

This was a non-randomized, prospective study. All subjects were enrolled from healthy volunteers.

Methods

Subjects aged 37-9, 40-42, 43-45 and 46-48 that have 20/20 best-corrected distance visual acuity (BCDVA) were included. Binocular visual acuity at different defocus steps ranging from +0.5 D to -3 D was measured in each age group. Defocus curves were generated from the mean logMAR visual acuities at each defocus step, by age group.

Results

Of the 60 subjects, 23.3% of subjects were between the ages of 37-39, 26.7% were between the ages of 40-42, 25% of subjects were between ages 43-45, and 25% were between the ages of 46-48. Visual acuity significantly decreased from plano to -3 D defocus steps in all groups (p < 0.0002, p = 0, p = 0 and p = 0). The 46-48-year-old group had worse visual acuity compared to the other three groups from the -1.0 to -2.0 D defocus steps (p = 0.037, p = 0.022 and 0.017, respectively). Starting at a near point of 40cm, the 37-39 group had the best logMAR vision and the 46-48 group had the worst vision (p = 0.001).

Conclusion

The defocus curves of emerging presbyopic individuals demonstrate a decreasing visual acuity at near defocus steps that decreases with age. Defocus curves at different age ranges can help doctors explain various presbyopia treatment options in terms of near point capabilities at various ages.

Clinical Outcomes of a Non-Diffractive Extended Depth-of-Focus IOL in Eyes with Mild Glaucoma

Purpose

To evaluate the clinical outcomes of a non-diffractive, wavefront-shaping extended depth-of-focus (EDOF) intraocular lens (IOL) in eyes with mild open-angle glaucoma (OAG).

Setting

Private practice; Sioux Falls, South Dakota.

Design

Prospective, open-label, interventional study.

Methods

In total, 52 eyes of 26 patients with mild OAG were enrolled and completed the study. All patients were bilaterally implanted with a non-diffractive, wavefront-shaping EDOF IOL. Seventy-seven percent of the patients were implanted with a trabecular microbypass stent at the time of surgery. Primary outcome measures included binocular corrected and uncorrected distance visual acuity (CDVA and UDVA), uncorrected intermediate and near visual acuity (UIVA and UNVA) and contrast sensitivity as measured by a Pelli-Robson chart. A subjective questionnaire was also administered to patients.

Results

At 4 months postoperative, the mean binocular UDVA and CDVA was 0.03 ± 0.12 and -0.06 ± 0.07, respectively. The mean UIVA and UNVA were 0.18 ± 0.12 and 0.31 ± 0.18, respectively. Eighty-five percent of the subjects achieved ≥20/25 UDVA and 77% of the subjects achieved ≥20/32 UIVA at 4 months postoperative. The mean binocular mesopic contrast sensitivity was 1.76 ± 0.16 at a spatial frequency of 1 cycle-per-degree (cpd). Eighty-five percent of the subjects reported they would choose the same lens and 1 subject reported they would choose a different IOL if it meant reduced spectacle independence.

Conclusion

The non-diffractive, wavefront-shaping EDOF IOL can be safely implanted in eyes with mild, pre-perimetric open-angle glaucoma with favorable uncorrected distance and intermediate visual acuity. The contrast sensitivity measurements were favorable and the subjective questionnaire revealed satisfactory spectacle independence and patient satisfaction.

Association between axial length and toric intraocular lens rotation according to an online toric back-calculator

AIM: To assess the relationship between axial length (AL) and intraocular lens (IOL) rotation among eyes receiving a toric IOL and subsequently entered into an online toric back-calculator database. METHODS: Retrospective analysis of data collected online via astigmatismfix.com, a freely available online toric back-calculator where surgeons enter pre- and post-operative information to help manage residual postoperative astigmatism. Included records were deemed valid with entry of AL and IOL orientation between January 2017 and March 2019. Rotation was determined by a difference of ≥5° between pre-operative intended IOL orientation and actual post-operative IOL orientation. Frequency and magnitude of rotation are presented with means and associated standard deviation (SD). Linear regression models of this association are presented. RESULTS: Records of 6752 eyes were included in the analysis, of which 74.8% were determined to have a rotated IOL. The magnitude of rotation increased with each millimeter (mm) increase in AL with a mean rotation of 13.3° (SD: 12.8°) for eyes with AL 20-20.9 mm and a maximum mean rotation of 30.6° (SD: 30.3°) among eyes with AL 29-29.9 mm. General linear modeling demonstrated a significant association (P&#x003C;0.0001) with a parameter estimate of 1.19 (standard error: 0.159) and R2 of 0.0083. CONCLUSION: Analysis from an online database indicates that toric IOLs inserted into eyes with longer AL are more likely to rotate and to rotate more degrees from the target axis. The findings from this study are clinically relevant for surgeons implanting toric IOLs.

The Effectiveness and Safety of Dextenza 0.4 mg for the Treatment of Postoperative Inflammation and Pain in Patients After Photorefractive Keratectomy: The RESTORE Trial

PURPOSE

To determine patient preference and treatment outcomes with an intracanalicular dexamethasone 0.4 mg insert compared to a standard steroid drop regimen in the contralateral eye following bilateral photorefractive keratectomy (PRK).

METHODS

In this randomized, prospective, self-controlled, open-label interventional study, one eye received the dexamethasone insert and the second eye received prednisolone acetate 1% taper following bilateral PRK surgery. Postoperative evaluations were performed on day 3, day 4, month 1, and month 3. Phone call surveys were performed on week 2. The Comparison of Ophthalmic Medications for Tolerability questionnaire was used to determine patient preference between postoperative regimens and postoperative pain. Corneal endpoints included time to epithelialization, presence of corneal haze, sodium fluorescein staining, and modified Standardized Patient Evaluation of Eye Dryness (SPEED) scores. Both corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA) were assessed.

RESULTS

Twenty patients participated in the study. At month 3, 70% of patients preferred the dexamethasone insert, 20% preferred prednisolone acetate, and 10% expressed no preference. Patient surveys did not show a difference in postoperative pain between the study group and control group. No statistical difference was shown in time to epithelialization, 90-day CDVA or UDVA, postoperative corneal haze, corneal staining, or modified SPEED scores.

CONCLUSIONS

In patients undergoing PRK, there was preference toward a dexamethasone insert in place of topical prednisolone acetate for the postoperative steroid treatment. There were no statistically or clinically significant differences between the two cohorts in regard to healing time or visual outcomes. [J Refract Surg. 2021;37(9):590-594.].

The corneal endothelium: clinical review of endothelial cell health and function

The endothelial cell is a critical structure within the cornea and is responsible for maintaining corneal clarity through its pump function. Endothelial cells are lost over time naturally but can be injured medically, surgically, or as a part of various dystrophies. Monitoring of endothelial cells can be performed clinically or more formally with specular microscopy. In cases of significant compromise, endothelial cells can be transplanted by various endothelial keratoplasty techniques. The future pipeline is bright for possible endothelial cell regeneration and rehabilitation. This article reviews these topics in depth to provide a comprehensive look at the structure and function of the endothelial cell, etiologies of endothelial cell damage, detailed review of iatrogenic causes of endothelial cell loss, and management strategies.

The Effects of Glaucoma and Glaucoma Therapies on Corneal Endothelial Cell Density

A healthy corneal endothelium is required for corneal clarity. Both the glaucoma disease state and its various forms of treatment can have adverse effects on the corneal endothelium. Both the presence of glaucoma and the magnitude of intraocular pressure elevation are related to endothelial cell loss (ECL). Topical medical therapy, laser procedures, and both traditional surgeries-trabeculectomy and tube-shunts-and newer minimally invasive glaucoma surgeries have variable effects on ECL. This review will summarize the reported effects of glaucoma and its treatment on ECL. Concerns for corneal endothelial cell health should be part of the decision-making process when planning glaucoma therapy for lowering intraocular pressure, with added caution in case of planned device implantation in eyes with preexisting ECL and low endothelial cell density at high risk for corneal endothelial decompensation.

Descemet Membrane Endothelial Keratoplasty and light adjustable lens triple procedure

Purpose

The objective of this series is to report the early post-operative visual outcomes of a novel triple procedure utilizing Descemet membrane endothelial keratoplasty (DMEK) plus light adjustable lens (LAL) in two patients (four eyes).

Methods

Two patients with bilateral, visually significant cataracts and Fuchs' dystrophy were selected for DMEK plus LAL triple procedure. Patient B also exhibited a high amount of preoperative astigmatism. Both patients desired spectacle independence and were initially targeted for monovision with the dominant eye corrected for distance and the nondominant eye corrected for near. Best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), and manifest refraction were recorded at each postoperative appointment and light treatment.

Results

In the early post-operative course, Patient A chose to pursue binocular distance correction instead of monovision. This was adjusted for accordingly using the LAL. Following final lock-in, Patient A had a distance UCVA of 20/15 in the right eye (OD) and a distance UCVA of 20/20 in the left eye (OS). Patient B was targeted for monovision. After final lock-in, Patient B had a distance UCVA of 20/15 in the dominant eye (OD) and a near UCVA of Jaeger No. 1+ in the nondominant eye (OS).

Conclusions and Importance

The first reported cases of DMEK plus LAL triple procedures achieved exceptional UCVA at the desired target. The post-operative customizability of the LAL allows for the achievement of excellent refractive outcomes after DMEK, even in patients with significant astigmatism and in patients who change their mind regarding refractive target.

Corneal cross-linking versus conventional management for keratoconus: a lifetime economic model

AIMS

To assess the cost-effectiveness of corneal collagen cross-linking (CXL) versus no CXL for keratoconus in the United States (US).

METHODS

A discrete-event microsimulation was developed to assess the cost-effectiveness of corneal cross-linking (CXL, Photrexa + KXL combination product) versus no CXL for patients with keratoconus. The lifetime model was conducted from a US payor perspective. The source for CXL efficacy and safety data was a 12-month randomized, open-label, sham-controlled, multi-center, pivotal trial comparing CXL versus no CXL. Other inputs were sourced from the literature. The primary outcome was the incremental cost per quality-adjusted life year gained. Costs (2019 USD) and effects were discounted 3% annually. The impacts of underlying uncertainty were evaluated by scenario, univariate, and probabilistic analyses.

RESULTS

Starting at a mean baseline age of 31 years and considering a mixed population consisting of 80% slow-progressors and 20% fast-progressors, the CXL group was 25.9% less likely to undergo penetrating keratoplasty (PK) and spent 27.9 fewer years in advanced disease stages. CXL was dominant with lower total direct medical costs (-$8,677; $30,994 versus $39,671) and more QALYs (1.88; 21.80 versus 19.93) compared to no CXL. Considering the impact of reduced productivity loss in an exploratory scenario, CXL was associated with a lifetime cost-savings of $43,759 per patient. CXL was cost-effective within 2 years and cost-saving within 4.5 years.

LIMITATIONS

Limitations include those that are common to similar pharmacoeconomic models that rely on disparate sources for inputs and extrapolation on short-term outcomes to a long-term analytical horizon.

CONCLUSIONS

Keratoconus is a progressive and life-altering disease with substantial clinical, economic, and humanistic consequences. The economic value of cross-linking is maximized when applied earlier in the disease process and/or younger age, and extends to improved work productivity, out-of-pocket costs, and quality of life.

Rotation Characteristics of Three Toric Monofocal Intraocular Lenses

Purpose

To evaluate the rotational stability of the three monofocal toric intraocular lenses (IOLs) via data from an online toric IOL back-calculator.

Methods

A retrospective data review of an online toric IOL back-calculator, which allows users to input preoperative toric planning information, postoperative lens orientation, and subjective refraction. Inputted data were used to determine the optimal orientation of the toric IOL to minimize residual refractive astigmatism. Aggregate data from 3/11/2019 to 3/10/2020 were extracted and validated. Only data with ≥0.5D of residual refractive astigmatism were used in the study. Pre-operative intended IOL orientation and post-operative IOL orientation were used to calculate IOL rotation.

Results

After validation, 5397 entries were determined to represent patient eyes, of which 3238 represented the three monofocal IOLs evaluated. The rate of rotation for AcrySof, TECNIS, and enVista Toric IOLs was 72.7%, 83.4%, and 83.0%, respectively, and location only significantly impacted TECNIS IOLs. The magnitude of rotation for rotated IOLs was similar for all models and was significantly more for IOLs initially placed in the oblique axis. All IOL models tended to rotate in a counterclockwise direction (53.2%, 73.0%, 69.7%, respectively; p<0.05), and the tendency was greater for IOLs initially located horizontally.

Conclusion

The AcrySof IQ Toric IOL was more rotationally stable than both the TECNIS and enVista Toric IOLs; there was no significant difference in rotational stability of the latter two.

Periodic normalization of the translaminar pressure gradient prevents glaucomatous damage

The 24-hour intraocular pressure (IOP) rhythm is of interest to clinicians but its overall impact on glaucomatous progression remains unclear. Recent evidence has implicated the translaminar pressure gradient (TLPG), or imbalance between IOP and intracranial pressure, in the development of glaucoma. Evidence suggests that retinal ganglion cell death occurs as a result of decreased axonal transport only after a sustained, elevated TLPG. We hypothesize that periodic normalization of the TLPG prevents glaucomatous damage by enabling temporary resumption of axonal transport. Temporary resumption of axonal transport allows for delivery of critical metabolic cargoes with concomitant removal of metabolic waste which prevents apoptosis of the retinal ganglion cell.

Evaluation of the IOP-Lowering Effect of a Multi-Pressure Dial at Different Negative Pressure Settings

Purpose

To evaluate the intraocular pressure (IOP)-lowering effect of a multi-pressure dial (MPD) at targeted negative pressure settings.

Methods

Prospective, intrasubject controlled study of 65 healthy subjects randomized to receive no negative pressure for 60 minutes or negative pressure application at designated levels of 25%, 50%, and 75% of baseline IOP for 20 minutes each. The main outcome measure was mean IOP with application of negative pressure.

Results

In the study eye group, from a baseline IOP of 15.8 ± 3.6 mm Hg, the mean IOP was 13.5 ± 3.4, 11.5 ± 3.1, and 10.2 ± 2.7 mm Hg with negative pressure settings of 25%, 50% and 75%, respectively. In the control eye group, from a baseline IOP of 15.5 ± 3.0 mm Hg, the mean IOP values at the same time points, without negative pressure, were 15.6 ± 3.0, 15.5 ± 2.5 and 15.3 ± 2.4 mm Hg. The difference between the mean IOPs of the two groups was significantly different at all negative pressure settings (P < 0.001) in comparison with baseline. There was one minor adverse event, a corneal abrasion, that was unrelated to device wear.

Conclusions

Negative pressure application to the periocular space with a multi-pressure dial can produce titratable IOP reduction while the device is worn with active negative pressure. To our knowledge, this technology represents the first nonpharmacologic, nonlaser, nonsurgical method for IOP reduction.

Translational Relevance

This represents the first study demonstrating the IOP-lowering ability of the multi-pressure dial, a device that uses a novel IOP-lowering strategy by delivering negative pressure to the periocular region.

Three-Decade Evaluation of Cerebrospinal Fluid Pressure in Open-Angle Glaucoma at a Tertiary Care Center

Elevated intraocular pressure (IOP) is the most prevalent risk factor for primary open-angle glaucoma. However, IOP alone does not fully describe a mechanical basis for disease in patients with normal tension glaucoma or primary open-angle glaucoma. The translaminar pressure difference (TLPD) theory proposes that the pressure gradient generated by the difference of IOP and cerebrospinal fluid pressure (CSFp) acting at the level of the optic nerve can lead to cupping and glaucoma when IOP is higher than normal and/or CSFp is lower than normal. The study results to date have generally supported the TLPD theory; however, varying methods, populations, and sample sizes make it difficult to compare results. To further assess whether there is an association between low CSFp and open-angle glaucoma, 30 years of clinical data that assess 96,543 lumbar punctures were analyzed. Patients with open-angle glaucoma showed a significantly lower CSFp than randomly selected normal control patients (9.9 ± 3 mm·Hg (n = 86) versus 12.1 ± 3.6 mm·Hg (n = 114), p < 0.001) following adjustment for age and sex. This retrospective study provides strong evidence for an association between open-angle glaucoma and low CSFp.

Overnight Safety Evaluation of a Multi-Pressure Dial in Eyes with Glaucoma: Prospective, Open-Label, Randomized Study

Purpose

To investigate the safety and tolerability of the multi-pressure dial (MPD) worn overnight for seven consecutive days.

Design

Prospective, open-label, randomized, single-site study.

Subjects

Twenty eyes of 10 subjects with open-angle glaucoma were fitted with an MPD and randomized to negative pressure application of −10 mmHg in one eye (study eye) worn overnight for 7 consecutive days.

Methods

Safety measures included best-corrected visual acuity (BCVA), intraocular pressure (IOP) changes from baseline during and after negative pressure application, slit lamp and dilated fundus exam findings, and rate of adverse events. Subjective assessments were completed daily by the subjects during the 7-day study period and immediately following the study period.

Results

Prior to the 7-day testing period, application of 10 mmHg negative pressure reduced mean IOP from 18.2 ± 3.8 mmHg to 14.0 ± 2.1 mmHg (p<0.01), a 22% reduction. After 7 days of consecutive nightly wear, repeat IOP measurements with the application of negative pressure showed a decrease in mean IOP from 16.9 ± 4.3 mmHg to 13.5 ± 3.7 mmHg. The observed IOP reduction was in addition to the subjects’ current treatment regimen. There were no statistically significant changes in IOP, BCVA from baseline following the 7-day period of nightly wear with the application of negative pressure. The patient-reported outcomes were favorable.

Conclusion

The MPD can safely and comfortably be worn overnight. The decrease in IOP of >20% in addition to current therapy is both clinically and statistically significant. The MPD shows promise as a potential new treatment option for nocturnal IOP control.

An algorithm for the preoperative diagnosis and treatment of ocular surface disorders

Any ocular surface disease (OSD), but most commonly, dry-eye disease (DED), can reduce visual quality and quantity and adversely affect refractive measurements before keratorefractive and phacorefractive surgeries. In addition, ocular surgery can exacerbate or induce OSD, leading to worsened vision, increased symptoms, and overall dissatisfaction postoperatively. Although most respondents of the recent annual American Society of Cataract and Refractive Surgery (ASCRS) Clinical Survey recognized the importance of DED on surgical outcomes, many were unaware of the current guidelines and most were not using modern diagnostic tests and advanced treatments. To address these educational gaps, the ASCRS Cornea Clinical Committee developed a new consensus-based practical diagnostic OSD algorithm to aid surgeons in efficiently diagnosing and treating visually significant OSD before any form of refractive surgery is performed. By treating OSD preoperatively, postoperative visual outcomes and patient satisfaction can be significantly improved.

Prospective Interventional Cohort Study of Ocular Surface Disease Changes in Eyes After Trabecular Micro-Bypass Stent(s) Implantation (iStent or iStent inject) with Phacoemulsification

Introduction

This study sought to assess ocular surface disease changes following cataract surgery combined with trabecular micro-bypass stent(s) implantation (iStent or iStent inject).

Methods

This prospective interventional single-arm clinical trial enrolled 47 eyes with mild-to-moderate open-angle glaucoma (OAG) on 1–4 glaucoma medications who underwent phacoemulsification and trabecular micro-bypass stent(s) implantation. Key glaucoma and ocular surface data through 3 months postoperatively included the Ocular Surface Disease Index score (OSDI), corneal/conjunctival staining (Oxford Schema), fluorescein tear break-up time (FTBUT), conjunctival hyperemia (Efron Scale), glaucoma medications, and intraocular pressure (IOP).

Results

Mean OSDI scores improved from 40.1 ± 21.6 (severe) preoperatively to 17.5 ± 15.3 (mild) at 3 months (p < 0.0001). While 73% of eyes had moderate or severe OSDI scores preoperatively, 29% had such scores at 3 months, and the OSDI score was normal in 57% of eyes versus 9% preoperatively. Mean FTBUT increased from 4.3 ± 2.4 s preoperatively to 6.4 ± 2.5 s at 3 months (p < 0.0001); mean Oxford corneal/conjunctival staining reduced from 1.4 ± 1.0 preoperatively to 0.4 ± 0.6 at 3 months (p < 0.0001); mean Efron conjunctival hyperemia score reduced from 1.4 ± 0.7 preoperatively to 1.2 ± 0.6 at 3 months (p = 0.118). The number of glaucoma medications decreased from 1.5 ± 0.9 to 0.6 ± 0.8 mean medications (60% reduction, p < 0.0001), with all eyes maintaining or reducing medications versus preoperatively and 55% of eyes becoming medication-free (versus 0% preoperatively). Mean IOP reduced from 17.4 ± 4.2 mmHg to 14.5 ± 3.2 mmHg (p < 0.0001). The safety profile was excellent.

Conclusion

Implantation of trabecular micro-bypass stent(s) (iStent or iStent inject) with cataract surgery produced significant improvements in ocular surface health, alongside significant reductions in IOP and medications.

Trial registration

ClinicalTrials.gov identifier, NCT04452279.

Twelve-Month Outcomes of Stand-Alone Excisional Goniotomy in Mild to Severe Glaucoma

PURPOSE

To describe 12-month intraocular pressure (IOP) and medication use outcomes following excisional goniotomy (EG) as a stand-alone procedure in eyes with medically uncontrolled glaucoma.

METHODS

This was a retrospective analysis of data from surgeons at 8 centers (6 US, 2 Mexico). Eyes with glaucoma undergoing standalone EG with a specialized instrument (Kahook Dual Blade, New World Medical, Rancho Cucamonga, CA) for IOP reduction and followed for 12 months postoperatively were included. Data were collected preoperatively, intraoperatively, and 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. The primary outcome was reduction from baseline in IOP, and key secondary outcomes included IOP-lowering medication reduction as well as adverse events.

RESULTS

A total of 42 eyes were analyzed, of which 36 (85.7%) had mild to severe primary open-angle glaucoma (POAG). Mean (standard error) IOP at baseline was 21.6 (0.8) mmHg, and mean number of medications used at baseline was 2.6 (0.2). At 3, 6, and 12 months postoperatively, mean IOP reductions from baseline were 4.6 mmHg (22.3%), 5.6 mmHg (27.7%), and 3.9 mmHg (19.3%) (p≤0.001 at each time point). At the same time points, mean medications reductions of 0.7 (25.8%), 0.9 (32.6%), and 0.3 (12.5%) medications were seen (p<0.05 at months 3 and 6, not significant at month 12). Six eyes (14.3%) underwent additional glaucoma surgery during the 12-month follow-up period.

DISCUSSION

Standalone EG with KDB can reduce IOP, and in many cases reduce medication use, through up to 12 months in eyes with mild to severe glaucoma. Statistically significant and clinically relevant reductions in IOP were seen at every time point. While the goal of surgery was not to reduce medication burden, mean medication use was significantly reduced at all but the last time point. In the majority of eyes, the need for a bleb-based glaucoma procedure was delayed or prevented for at least 12 months.

iStent Trabecular Microbypass Stent Implantation with Phacoemulsification in Patients with Open-Angle Glaucoma: 6-Year Outcomes

Purpose

To investigate the long-term safety and efficacy of an iStent trabecular microbypass stent in combination with cataract surgery in eyes with primary open-angle glaucoma (POAG).

Setting

Private practice; Sioux Falls, South Dakota.

Design

Retrospective, consecutive case series.

Methods

This case series included eyes implanted with a single trabecular microbypass stent in combination with phacoemulsification in patients with mild to severe POAG. Data were collected preoperatively and at day 1, week 1, month 1, and up to 6 years postoperatively. Primary outcome measures included mean intraocular pressure (IOP) and number of glaucoma medications. Safety was noted by assessing the incidence of IOP spikes and need for additional surgery.

Results

The study comprised 411 eyes. Mean IOP was reduced to 14.9±4.2 mmHg compared to 18.8±5.6 mmHg at baseline at 6 years postoperative. The mean number of medications was reduced to 1.2±1.0 from 1.4±1.1 at baseline. In eyes with severe stage of disease, there was a mean IOP reduction >6 mmHg at 6 years postoperative. Eyes with baseline IOP ≥18 mmHg achieved a more robust reduction in IOP. Fifteen eyes underwent a secondary glaucoma procedure. There were no intra- or postoperative complications.

Conclusion

Trabecular microbypass stent implantation in combination with cataract surgery provides a sustained IOP reduction in eyes with mild-to-severe POAG. The degree of IOP reduction was more significant in eyes with higher baseline IOP and severe stage of disease.

Intraocular Pressure Measurement with Pneumatonometry and a Tonometer Tip Cover

Purpose

To investigate the precision and accuracy of IOP measurements using a pneumatonometer and a tonometer tip cover (Tono-Pen^® tip cover) acting as a membrane between a cadaver eye model and pneumatonometer probe.

Methods

A total of 480 paired IOP measurements, with and without a Tono-Pen cover, were collected across 4 pressure levels of 7, 10, 20 and 30 mmHg. IOP measurements were obtained by three different pneumatonometer units paired with three different masked operators (three configurations). Four eyes were sampled for each eye pressure level. The sequence of eye pressure, configuration, and measurements with vs. without the Tono-Pen cover was randomized.

Results

With the Tono-Pen cover in place, there was a negative bias with a mean IOP difference of − 1.18 mmHg for all 480 paired samples compared with the measurements absent the cover. Compared with the test pressure settings (i.e., 7, 10, 20, 30 mmHg), the overall mean bias was + 0.35 mmHg with the Tono-Pen cover present. With the Tono-Pen cover present, the overall repeatability %CV (percent coefficient of variation) was 3.4% and the reproducibility %CV was 3.8% compared with a repeatability %CV of 3.2% and reproducibility %CV of 5.7% without the Tono-Pen cover.

Conclusion

Measurement of IOP via pneumatonometry with a Tono-Pen cover in place, also known as the excursion test method, yields precise, accurate and reproducible results. This developed method of pressure measurement is an acceptable and reliable form of IOP measurement.

Goniotomy with a single-use dual blade: Short-term results

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of a single-use dual blade (Kahook) in patients with mild to end-stage glaucoma.

SETTING

International multicenter ophthalmic care centers.

DESIGN

Prospective interventional case series.

METHODS

Consecutive patients with glaucoma who had phacoemulsification plus goniotomy with the single-use dual blade were enrolled in this study. Each center collected deidentified clinical data, including preoperative and postoperative IOP, medication use, adverse events, and whether additional surgery was required during a 6-month follow-up.

RESULTS

Of the 71 eyes included in this study, 70% had primary open-angle glaucoma. Other diagnoses included angle-closure, pigmentary, pseudoexfoliative, and normal-tension glaucoma. Sixty-five percent of eyes were classified as having mild to moderate glaucoma and 35%, severe glaucoma. The mean baseline IOP decreased from 17.4 mm Hg ± 5.2 (SD) to 12.8 ± 2.6 mm Hg 6 months postoperatively and the hypotensive medication use decreased from 1.6 ± 1.3 to 0.9 ± 1.0, respectively (P < .001 and P = .005, respectively). The most common observation was blood reflux during surgery (39.4%).

CONCLUSION

Single-use dual blade goniotomy plus phacoemulsification resulted in a significant and sustained reduction in IOP and a decrease in glaucoma medications after 6 months of follow-up.

8 hrs Safety Evaluation Of A Multi-Pressure Dial In Eyes With Glaucoma: Prospective, Open-Label, Randomized Study

Purpose

To investigate the safety and tolerability of the multi-pressure dial with a continuous 8-hr duration in subjects with open-angle glaucoma.

Design

Prospective, controlled open-label, randomized, single site study.

Subjects

Twenty eyes of 10 subjects with open-angle glaucoma were fitted with a multi-pressure dial and randomized to negative pressure application of −10 mmHg in one eye for 8 (continuous) hours and ambient atmospheric pressure in the contralateral eye.

Methods

Main safety outcome measures include best-corrected visual acuity (BCVA), intraocular pressure (IOP) changes from baseline after negative pressure application, slit lamp and dilated fundus exam findings, and rate of adverse events. Subjective assessments were administered both hourly during the 8-hr study period and immediately following the study period.

Results

There were no statistically significant changes in IOP, BCVA or TBUT immediately following the 8-hr study period or at the 1-week follow-up visit. Patient-reported tolerability was favorable with a mean response of 1.8 ± 0.4 (scale → 1=best, 10 = worst). Subjects also reported positive interest in the MPD as a glaucoma therapy with a mean response of 1.8 ± 0.5 (scale → 1=best, 10 = worst). One adverse event was reported (headache) and resolved at conclusion of the Day 0 visit.

Conclusion

The MPD demonstrated favorable safety with key parameters remaining stable after an 8-hr wear with negative pressure. Negative pressure application through the MPD was well tolerated by subjects enrolled in the study. The favorable findings demonstrate the safety of sustained delivery of negative pressure over a continuous, uninterrupted 8-hr duration.

Extended depth of focus lens implantation after radial keratotomy

Purpose

To identify the visual performance of radial keratotomy (RK) patients that have undergone cataract surgery with implantation of an extended depth of focus (EDOF) intraocular lens (IOL).

Design

Retrospective chart review with questionnaire.

Methods

Medical charts of patients with a history of RK that had undergone phacoemulsification with implantation of the Tecnis Symfony IOL (J&J Vision) were reviewed. Data collected included preoperative demographics, number of RK incisions, pupil size, and preoperative visual acuity and manifest refraction. Primary outcome measures of the study included postoperative uncorrected distance visual acuity (UCVA) and manifest refraction spherical equivalent (SE) at each follow-up visit. Secondary outcomes included results from a telephone questionnaire assessing visual performance and satisfaction.

Results

Twenty-four eyes of 12 patients were included. UCVA improved from an average Snellen equivalent 20/73 preoperatively to 20/33 at an average final follow-up of 6 months (P=0.0011), while average manifest SE improved from +1.68 D to −0.18 D (P<0.0001). At final follow-up, 15 of 24 eyes (62.5%) were at or within 0.5 D of target refraction, while 20 of 24 eyes (83.3%) were at or within 1.0 D. In total, 79% of eyes (19 of 24) had UCVA of 20/40 or better at distance. In the survey, 78% of patients reported satisfaction with their vision after surgery and 44% of patients reported being spectacle free for all tasks.

Conclusions

An EDOF lens implant can produce good visual outcomes and satisfaction in patients with a history of RK.

Refractive outcomes after trabecular microbypass stent with cataract extraction in open-angle glaucoma

PURPOSE

To evaluate the impact of trabecular microbypass stents combined with cataract surgery on refractive outcomes in patients with open-angle glaucoma (OAG).

SETTING

Private practice, Sioux Falls, South Dakota, USA.

DESIGN

Retrospective, comparative case series.

METHODS

Eyes with OAG had implantation of trabecular microbypass stents with concomitant cataract surgery. The unmatched control group comprised eyes that underwent only cataract extraction. Data were collected preoperatively and postoperatively for 6 months. Data included spherical equivalent (SE), astigmatic error, intraocular pressure (IOP), and number of glaucoma medications.

RESULTS

The series included 76 consecutive OAG eyes with combined cataract plus trabecular microbypass stent and 50 consecutive non-OAG eyes with cataract surgery only. SE outcomes were equivalent between the groups (P<0.001). For the combined and cataract-only groups respectively, 46% vs 52% had SEs within 0.25 D of the target, 80% vs 80% within 0.50 D, and 95% vs 94% within 1.00 D. Astigmatism outcomes did not significantly differ between the groups (P>0.05). As for magnitude of astigmatism in the combined and cataract only groups respectively, 51% vs 32% were within 0.5 D, 75% vs 66% within 1.0 D, 87% vs 82% within 1.5 D, and 89% vs 94% within 2.0 D. In the OAG combined-surgery group, mean intraocular pressure reduction was 3.4 mmHg (P<0.0001) at 1 month postoperatively, 4.0 mmHg (P<0.0001) at 3 months, and 3.4 mmHg (P<0.01) at 6 months. Mean decrease in number of glaucoma medications was 0.4 (P<0.05) at 1 month, 0.7 (p<0.0001) at 3 months, and 0.9 (P<0.001) at 6 months.

CONCLUSION

The results of this study suggest the trabecular microbypass stent is a refractively neutral device.

Residual astigmatism after toric intraocular lens implantation: Analysis of data from an online toric intraocular lens back-calculator

PURPOSE

To evaluate some possible causes for residual astigmatism after toric intraocular lens (IOL) implantation based on an analysis of data from an online toric IOL back-calculator.

DESIGN

Retrospective data review.

METHODS

An online toric back-calculator was designed to allow users to input preoperative toric planning information along with postoperative IOL orientation and refractive results. These were then used to determine the optimum orientation of the IOL to reduce refractive astigmatism. The collected aggregate data were extracted from this calculator to investigate the associated reasons for residual astigmatic refractive error with toric IOLs.

RESULTS

The study analyzed 12 812 records with a mean postoperative refractive astigmatism of 1.89 diopters (D). Refractive astigmatism was significantly higher with higher IOL cylinder power (P < .01) but was not different by IOL manufacturer. Ninety percent of IOLs were not at the ideal orientation, despite 30% being at the preoperative calculated orientation. Misalignment showed a directional bias for some IOLs but not for others. The mean calculated percentage reduction in residual cylinder after reorientation was 50% ± 31% (SD), with the magnitude of residual astigmatism after IOL reorientation expected to be 0.50 D or less in 37% of eyes (4835/12 812). Expected outcomes were significantly different by IOL type.

CONCLUSIONS

Analysis of data from the online toric back-calculator provided insights into the nature of residual astigmatism after toric IOL implantation. The reasons for residual astigmatism in this data set varied by IOL type.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Assessment of corneal hysteresis measured by the ocular response analyzer as a screening tool in patients with glaucoma

Background

Corneal hysteresis (CH) is used to determine the level of risk of patients developing glaucoma, categorized as suspect, mild, moderate and severe.

Methods

This is a retrospective review of 126 consecutive eyes presenting, for the first time, at a glaucoma subspecialty clinic. All eyes at initial examination underwent measurement of CH and intraocular pressure using the Goldmann applanation tonometry (IOPgat). Eyes were classified as CH<10 (n=51) or CH≥10 (n=75) and categorized into glaucoma suspect, mild, moderate, or severe glaucoma based on 24−2 Humphrey visual field testing. Additional data included number of topical glaucoma medications.

Results

Of the eyes classified as a CH<10, 45.5% had moderate or severe glaucoma, and 11.8% of eyes with a CH≥10 had moderate or severe glaucoma. In the CH≥10 group, the mean IOPgat was 19.5 mmHg ± 4.72 mmHg (P<0.01) on 1 ± 1.26 (P<0.01) medications in the moderate/severe glaucoma group and 20.13 mmHg ± 4.95 mmHg (P<0.01) on 0.60 ± 0.95 (P<0.01) medications in the glaucoma suspect/mild glaucoma group. In the CH<10 group, mean IOPgat was 20.47 mmHg ± 7.56 mmHg (P<0.01) on 1.79 ± 1.17 (P<0.01) medications in the moderate/severe glaucoma group. Mean IOPgat was 17.54 mmHg ± 5.48 mmHg (P<0.01) on 0.63 ± 0.83 (P<0.01) medications in the glaucoma suspect/mild glaucoma group.

Conclusion

Moderate to severe glaucoma is 2.9 (P<0.01) times more likely to occur in eyes that measure a CH<10 compared to eyes that measure a CH≥10. Although not statistically significant, suspect or mild glaucoma is more common in eyes that measure a CH≥10. Eyes in the CH<10 moderate/severe glaucoma group had statistically significant higher IOPgat (P<0.01) compared to the CH<10 suspect/mild glaucoma group. Measuring CH at initial presentation can help predict the severity of glaucoma.

Influences on rebubble rate in Descemet's membrane endothelial keratoplasty

Purpose

Descemet’s membrane endothelial keratoplasty (DMEK) is a minimally invasive partial corneal transplant procedure used in patients with failing endothelial membranes. This study aims to identify those factors which influence the need for a rebubble of the corneal graft.

Methods

A total of 94 eyes that received DMEK between March 2014 and January 2016 at Vance Thompson Vision were used in the study. Demographic and graft data were collected from the patients and donors, and perioperative statistics of the procedures. A logistical regression was used to compare eyes that did and did not require a rebubble.

Results

Among those characteristics that were included (patient age/sex, donor age/sex, death to processing time, donation to surgery time, death to procurement time, specular cell count density, burping procedure, postoperative day 1 intraocular pressure [IOP], and postoperative week 1 IOP, concurrent phacoemulsification, and how well the Descemet graft was centered), only a lower specular cell count density of the corneal graft, and a graft that was not well-centered correlated with needing a rebubble due to partial graft detachment (p=0.021) and (p=0.023), respectively.

Conclusion

An increased specular cell count density may allow for better placement of the corneal graft by allowing for better unfolding in DMEK procedures. A well-centered graft may decrease postoperative complications by increasing adherence. Additionally, postoperative management of IOP may not affect the rebubble rate, and therefore should be left to the discretion of the provider to determine whether it is necessary.

Cost-comparison of two trabecular micro-bypass stents versus selective laser trabeculoplasty or medications only for intraocular pressure control for patients with open-angle glaucoma

AIM

Patients with open-angle glaucoma (OAG) whose intraocular pressure is not adequately controlled by one medication have several treatment options in the US. This analysis evaluated direct costs of unilateral eye treatment with two trabecular micro-bypass stents (two iStents) compared to selective laser trabeculoplasty (SLT) or medications only.

MATERIALS AND METHODS

A population-based, annual state-transition, probabilistic, cost-of-care model was used to assess OAG-related costs over 5 years. Patients were modeled to initiate treatment in year zero with two iStents, SLT, or medications only. In years 1-5, patients could remain on initial treatment or move to another treatment option(s), or filtration surgery. Treatment strategy change probabilities were identified by a clinician panel. Direct costs were included for drugs, procedures, and complications.

RESULTS

The projected average cumulative cost at 5 years was lower in the two-stent treatment arm ($4,420) compared to the SLT arm ($4,730) or medications-only arm ($6,217). Initial year-zero costs were higher with two iStents ($2,810) than with SLT ($842) or medications only ($996). Average marginal annual costs in years 1-5 were $322 for two iStents, $777 for SLT, and $1,044 for medications only. The cumulative cost differences between two iStents vs SLT or medications only decreased over time, with breakeven by 5 or 3 years post-initiation, respectively. By year 5, cumulative savings with two iStents over SLT or medications only was $309 or $1,797, respectively.

LIMITATIONS

This analysis relies on clinical expert panel opinion and would benefit from real-world evidence on use of multiple procedures and treatment switching after two-stent treatment, SLT, or polypharmaceutical initial approaches.

CONCLUSIONS

Despite higher costs in year zero, annual costs thereafter were lowest in the two-stent treatment arm. Two-stent treatment may reduce OAG-related health resource use, leading to direct savings, especially over medications only or at longer time horizons.

Analysis of Cerebrospinal Fluid Pressure Estimation Using Formulae Derived From Clinical Data

Purpose

To evaluate a frequently used regression model and a new, modified regression model to estimate cerebrospinal fluid pressure (CSFP).

Methods

Datasets from the Beijing iCOP study from Tongren Hospital, Beijing, China, and the Mayo Clinic, Rochester, Minnesota, were tested in this retrospective, case-control study. An often-used regression model derived from the Beijing iCOP dataset, but without radiographic data, was used to predict CSFP by using demographic and physiologic data. A regression model was created using the Mayo Clinic dataset and tested against a validation group. The Mayo Clinic-derived formula was also tested against the Beijing Eye Study population. Intraclass correlation was used to assess predicted versus actual CSFP.

Results

The Beijing-derived regression equation was reported to have an intraclass correlation coefficient (ICC) of 0.71, indicating strong correlation between predicted and actual CSFP in the study population. The Beijing iCOP regression model poorly predicted CSFP in the Mayo Clinic population with an ICC of 0.14. The Mayo Clinic-derived regression model similarly did not predict CSFP in its Mayo Clinic validation group (ICC 0.28 ± 0.04) nor in the Beijing Eye Study population (ICC 0.06).

Conclusions

Formulae used to predict CSFP derived from clinical data fared poorly against a large retrospective dataset. This may be related to differences in lumbar puncture technique, in the populations tested, or the timing of collection of physiologic variables in the Mayo Clinic dataset. Caution should be used when interpreting results based on formulaic derivation of CSFP.

Microbypass stent implantation with cataract extraction and endocyclophotocoagulation versus microbypass stent with cataract extraction for glaucoma

PURPOSE

To compare the outcomes of combined microbypass stent implantation, cataract extraction, and endocyclophotocoagulation (ECP) with those of implantation of the same microbypass stent with concomitant cataract surgery in patients with open-angle glaucoma (OAG).

SETTING

Private Practice, Sioux Falls, South Dakota, USA.

DESIGN

Retrospective consecutive case series.

METHODS

Patients from January 2015 to August 2016 were included. The study group comprised eyes that had implantation of a microbypass stent in combination with cataract extraction and ECP. To compare outcomes, a control group of eyes with similar baseline characteristics that had implantation of a stent in combination with cataract surgery was established. Data were collected preoperatively and postoperatively at 1 day, 1 week, and 1, 3, 6, and 12 months. Data included intraocular pressure (IOP) and number of glaucoma medications.

RESULTS

The mean preoperative IOP was 21.49 mm Hg ± 9.56 (SD) in the study group (51 eyes) and 20.66 ± 3.23 mm Hg in the control group (50 eyes). Twelve months postoperatively, the mean IOP reduction was 7.14 mm Hg in the study group and 4.48 mm Hg in the control group and the medication reduction was 38% (0.68) and 63% (1.06), respectively.

CONCLUSIONS

Patients who had implantation of the microbypass stent in combination with cataract surgery and ECP had significantly better IOP reduction than those who did not have ECP. The combination procedure was also effective in patients with severe OAG.

Small-incision 4-point scleral suture fixation of a foldable hydrophilic acrylic intraocular lens in the absence of capsule support

PURPOSE

To determine the visual outcomes and complications of a new small-incision technique for 4-point fixation of a hydrophilic acrylic posterior chamber intraocular lens (IOL) in the absence of capsule support.

SETTING

Three North American tertiary referral centers and a private practice.

DESIGN

Retrospective case series.

METHODS

Secondary IOL placement was performed from 2011 to 2014. Indications for surgery, clinical results, and complications were analyzed. Primary outcomes included postoperative corrected distance visual acuity (CDVA) and surgical complications.

RESULTS

Charts of 35 patients (37 eyes) were reviewed. The mean age at surgery was 56 years, and the mean follow-up was 6 months (range 3 to 24 months). Clinical indications included a dislocated IOL (30%), ocular trauma (19%), crystalline lens subluxation (19%), uveitis-glaucoma-hyphema syndrome (5%), post-complicated cataract (8%), congenital cataract (8%), and decompensated cornea (3%). The mean CDVA improved from 20/80 preoperatively to 20/40 postoperatively (P < .01). Thirty-six eyes (97%) had an improved or unchanged CDVA, and 1 eye (3%) had a reduced CDVA because of worsening glaucoma. Postoperative complications included ocular hypertension (24%), iritis (5%), wound leakage (3%), transient corneal edema (3%), glaucoma requiring a tube shunt (3%), and IOL dislocation (3%).

CONCLUSION

Small-incision 4-point scleral fixation of the Akreos AO60 hydrophilic acrylic IOL in the absence of capsule support appears to be a safe and effective technique for secondary IOL placement.

FINANCIAL DISCLOSURES

Drs. Berdahl and Ayres are consultants to Bausch & Lomb, Inc. Drs. Ayres and Fram have received speaker fees from Bausch & Lomb. Dr. Terveen does not have a financial or proprietary interest in any material or methods mentioned.

Toric intraocular lens orientation and residual refractive astigmatism: an analysis

Purpose

To analyze intraocular lens (IOL) orientation data from an online toric back-calculator (astigmatismfix.com) for determining if differences were apparent by lens type.

Methods

A retrospective review of astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis.

Results

Of 12,812 total validated calculation records, 8,229 included intended orientation and lens identification data. Of the latter, 5,674 calculations (69%) involved lenses oriented 5° or more from their intended position. Using estimated toric lens usage data, the percentage of lenses with orientation ≥5° from intended was 0.89% overall, but the percentage varied significantly between specific toric lens brands (P<0.05). The percentage of back-calculations related to lenses that were not oriented as intended was also statistically significantly different by lens brand (P<0.05). When IOLs were misoriented, they were significantly more likely to be misoriented in a counterclockwise direction (P<0.05). This was found to be due to a bias toward counterclockwise orientation observed with one specific brand, a bias that was not observed with the other three brands analyzed here.

Conclusion

The percentage of eyes with lens orientation ≥5° from intended in the Toric Results Analyzer data set was <1% of toric IOLs in general, with the relative percentage of Tecnis^® Toric IOLs significantly higher than AcrySof^® Toric IOLs. Both of these had higher rates than the Staar^® Toric and Trulign^® Toric lenses, with the availability of higher Tecnis and AcrySof cylinder powers a likely contributing factor. The AcrySof Toric IOL appears to be less likely than the Tecnis Toric IOL to cause residual astigmatism as a result of misorientation. The Tecnis Toric IOL appears more likely to be misoriented in a counterclockwise direction; no such bias was observed with the AcrySof Toric, the Trulign^® Toric, or the Staar Toric IOLs.