Linear interstitial keratitis – a poorly explored clinical entity
Sadiq Said (Zürich | CH)
To expand the existing knowledge on the rare clinical entity of linear interstitial keratitis.
History and Signs:
This case series includes four healthy patients aged 10, 18, 20, and 21 years at the initial referral to our ophthalmology department at the University Hospital Zurich in Switzerland. All patients reported a sudden onset of painful red eye, with only Case 3 using corrective contact lenses. In the acute phase, all patients were suspected of having unilateral keratitis with conjunctival injection, corneal epithelial defects, and linear stromal opacities, with Case 2 additionally showing anterior chamber reaction and Case 3 exhibiting nummular keratitis. In each patient, we performed diagnostic corneal swabs for common bacteria, fungi, and viruses, all of which were inconclusive. We further assessed autoimmune serological markers and screened for HIV, hepatitis B and C, and syphilis in Cases 1, 3, and 4, and performed in vivo confocal microscopy in Case 2. While infectious screening was negative, we detected antinuclear antibodies in Cases 3 and 4.
Therapy and Outcome:
Case 1 displayed recurrent keratitis, ultimately leading to corneal perforation after mild ocular trauma, which we treated conservatively using bandage contact lenses with topical and systemic antibiotic coverage. At a follow-up five years after the initial presentation, the corrected visual acuity deteriorated from 0.6 LogMAR to 0.5 LogMAR. Case 2 showed pan-stromal corneal inflammation on in vivo confocal microscopy. In Cases 3 and 4, there was no clinical evidence of underlying rheumatologic disease. We treated all three patients using topical antibiotics, lubricating and corticosteroid-containing eye drops, and in Cases 2 and 4 additional antiviral agents due to initially suspected herpetic origin. The corrected visual acuity deteriorated from 0 LogMAR to 0.3 LogMAR in Case 2 and improved from 0.3 LogMAR in Case 3 and 0.6 LogMAR in Case 4 to 0 LogMAR in both patients.
Linear interstitial keratitis remains a rare entity. It seems to preferably affect adolescent patients. Future research should include autoimmune workup to reveal unknown causal relationships. Long-term patient follow-up is paramount to detect disease recurrence and activity, finally minimizing the risk for corneal rupture.
Decision Tree for predicting visual benefit in keratoconus patients considering corneal cross-linking combined with refractive treatment
Claude Kaufmann (Luzern | CH)
Background: To develop a fast and frugal decision tree to identify keratoconus patients most likely to benefit visually from the combination of corneal cross-linking with topography-guided photorefractive keratectomy (named CXL plus).
Methods: The outcome of interest was an improvement of uncorrected distance visual acuity (UDVA) by at least two lines at the 12 months follow-up. Preoperative and 12 months follow-up data from patients who received CXL plus (n=96) and CXL only (n=96) were used in a recursive partitioning approach to construct a frugal tree with three variables ("corneal thickness (>/< 430 um)", "patient interest in CXL plus (yes/no)", and "tomographic cylinder ( < / > 3 D)"). In addition, we estimated the probability of the outcome from a multivariate logistic regression model for each combination of variables used in the decision tree.
Results: In the complete sample, 101/192 (52.6%) patients improved by at least two lines in the 12 months follow-up. Patients affirmative in all three answers had a 75.6% (34/45) probability of gaining at least two lines of improvement in UDVA by CXL plus. The statistical model estimated a 66.0% probability for a successful outcome.
Conclusions: A fast and frugal tree consisting of three variables can be used to select a patient group with a high likelihood to benefit from CXL plus. The tree is useful in the preoperative counseling of keratoconus patients contemplating the CXL plus option, an intervention that is not fully covered by many health insurances.
Epi-off customized CXL with supplemental oxygen for keratoconus – 1-year results
Theo G. Seiler (Bern | CH)
PURPOSE: To evaluate potential advantages of supplemental oxygen in of epi-off customized CXL.
SETTING: Prospective observational study at the Department of Ophthalmology, University Hospital Bern, Switzerland
METHODS: Forty eyes of 40 patients with documented progressive keratoconus were treated with epi-off customized CXL using 15 mW/cm2 and maximal energy levels of 10 J/cm2. Twenty eyes were treated in an atmospheric (21% O2) environment, while 20 eye were treated in a hyperoxic environment (>90% O2) and followed for 1 years. Analyzed parameters were Scheimpflug tomographies, endothelial cell count, BSCVA and anterior segment OCT.
RESULTS: Keratoconus progression was halted in all eyes. Kmax regression in the supplemental oxygen subgroup was significantly greater compared to the normoxic subgroup (-3.4 vs. -0.8 D). High flattening (>4D) was observed in 8 eyes (40%) in the hyperoxic vs. 1 eyes (5%) in the normoxic subgroup. BSCVA increased in both groups, however, significantly more in the supplementary oxygen subgroup. Densitometry peaked in both groups by month 3 and reached preoperative values in the normoxic subgroup, but not completely in the supplementary oxygen subgroup. Demarcation lines were observed significantly deeper using CXL with supplemental oxygen (334 vs 230 microns).
CONCLUSIONS: Supplementary oxygen optimizes the effect and outcome of epi-off CXL with 15mW/cm2. Flattening, corneal regularization and visual acuity improvement go along with an increased haze formation and deeper demarcation line depth using supplemental oxygen.
Safety Of Epithelium-Off Corneal Cross-Linking For Keratoconus Performed In An Office-Based Setting
Farhad Hafezi (Dietikon | CH)
Purpose: To assess the safety of epithelium-off corneal cross-linking (epi-off CXL) in an office-based setting.
Setting: ELZA Institute, Zurich, Switzerland
Methods: We compared the complication rates of epithelium-off corneal cross-linking (epi-off CXL) performed in an office-based setting to those of epi-off CXL performed in an operating room. Consecutive epi-off CXL procedures (n=511), performed by a single surgeon in a procedure room at the ELZA Institute, Zurich, Switzerland.
Results: No cases of postoperative infectious keratitis were observed, and sterile infiltrates occurred in 10/511 (1.95%) of patients, all of whom responded well to topical steroid therapy. Delayed epithelialization (>7 days) occurred in 14/511 (2.74%) patients. No other adverse events were noted.
Conclusions: Office-based epi-off CXL does not seem to be associated with an increased complication risk when compared to operating room settings.
Complications after corneal collagen cross-linking (CXL)
Daniel Rudolf Muth (Zürich | CH)
Purpose: To present a case series of rare and severe complications after corneal collagen cross-linking (CXL) of keratoconus patients.
Methods: Single-center descriptive case series covering the period of 2015 to 2022 at the Department of Ophthalmology at the University Hospital Zurich, Switzerland.
Results: We present four eyes of four patients that showed severe unusual complications within the first month after corneal cross-linking (CXL). Three patients had been treated with the classic epithelium-off “Dresden protocol” (30 minutes riboflavin followed by 30 minutes UV exposition). One patient had been treated with the accelerated epithelium-off protocol (30 minutes riboflavin, followed by 10 minutes UV exposition). One patient presented with an extensive corneal edema due to rubbing the eye after treatment. Two patients showed a bacterial infectious keratitis due to Streptococcus pneumoniae and Staphylococcus hominis, Micrococcus luteus, Streptococcus epidermidis respectively. The latter of the two patients showed an extensive infectious, crystalline keratopathy. The fourth patient showed a severe ulcerative lesion where no infectious cause could be found. Therefore, an autoimmune keratolytic process had to be suspected. Apart from the corneal edema which resolved ad integrum, the other complications resulted in permanent corneal scarring and thinning. One patient needed an emergency amniotic transplant.
Conclusion: Severe complications after CXL remain rare. Most common causes are complications that are not directly associated with the treatment as such. Those indirect complications occur after the treatment during the healing course of the epithelium. Associations with the therapeutic contact lens and with inappropriate patient behavior are often suspected. Correctly performed corneal scrapings with repeated microbiological analysis and a detailed patient history are essential for establishing the correct diagnosis especially in complicated cases that do not respond to standard therapeutic regimes. This case series supports the efforts that are currently taken to improve the CXL technique in a way that postoperative complications are further reduced.
EYEMATE-SC Trial: 12-Month Safety, Performance and Accuracy of a Suprachoroidal Sensor for Telemetric Measurement of Intraocular Pressure
Amir Nassri (Lausanne | CH)
Background: Measuring and controlling intraocular pressure (IOP) are the basis of the follow-up and the treatment of glaucoma. Self-tonometry has been proposed as an alternative to measure IOP more precisely throughout the entire day. The novel EYEMATE-SC sensor is implanted in the suprachoroidal space to enable contactless continual IOP monitoring. The aim of the present study was to investigate the 1-year safety, performance and accuracy of the EYEMATE-SC in primary open-angle glaucoma (POAG) patients undergoing simultaneous non-penetrating glaucoma surgery (NPGS).
Methods: In this prospective, multicenter, open-label, single-arm, interventional clinical trial, 24 eyes of 24 POAG patients who were due to undergo NPGS (canaloplasty or deep sclerectomy) were enrolled. An EYEMATE-SC sensor was implanted during NPGS. Goldmann applanation tonometry (GAT) measures were compared with the sensors’ IOP measures at all post-operative visits during 12 months. Device position and adverse events were recorded throughout the follow-up.
Results: 15 eyes underwent canaloplasty and 9 underwent deep sclerectomy. Successful implantation of the sensor was achieved in all eyes with no reported intraoperative difficulties. Through the 12-month follow-up, no device migration, dislocation or serious device-related complications were recorded. A total of 536 EYEMATE-SC measures were pairwise included in the IOP agreement analysis. The overall mean difference between GAT and EYEMATE-SC measurements was 0.8 mmHg (limits of agreement (CI 95%, LoA): -5.1 and 6.7 mmHg). The agreement gradually improved and from 3-month post-operatively until the end of the follow-up, the mean difference was -0.2 mmHg (LoA: -4.6 and 4.2 mmHg) over a total of 264 EYEMATE-SC measures, and 100% of measures were within ± 5 mmHg of GAT.
Conclusions: The EYEMATE-SC sensor was safe and well-tolerated throughout 12 months. Moreover, it allowed accurate continuous IOP monitoring.
XEN Gel Stent implantation in open angle glaucoma: 5 year results of a prospective monocentric study
Julien Torbey (Lausanne | CH)
To evaluate 5-year treatment outcomes of XEN gel stent implantation in patients with open angle glaucoma.
In this prospective, single-centre interventional study, XEN implantation either alone or combined with phacoemulsification (Phaco + XEN) was performed on consecutive eyes with uncontrolled intraocular pressure (IOP) or disease progression despite medical treatment.
Main outcome measures:
Surgical success was defined as ’complete’ when 60-month unmedicated IOP was ≤15 mmHg with a relative IOP reduction ≥ 20% from medicated baseline, while the definition of qualified success allowed no more medications than at baseline. Secondary outcomes included mean IOP reduction, changes in ocular hypotensive medications and rates of reoperations.
Out of 170 eyes initially included, 80 eyes (53.7%) of 68 patients completed the 5-year follow-up and were included in the data (XEN: n = 17; Phaco + XEN: n = 63) after 46.3% were lost to follow-up. Mean age was 78.1 ± 9.1 years, and 69.8% were female. Mean medicated IOP decreased from 19.8 ± 7.0 mmHg (19.9 ± 7.8 [XEN] vs. 20.1 ± 7.6 mmHg [Phaco + XEN]) at baseline to 12.6 ± 3.1 mmHg (12.6± 3.1 [XEN] vs. 12.7 ± 3.1 [Phaco + XEN]) at 5 years (±37.0%; p < 0.001). Medications decreased from 2.0 ± 1.3 (2.0 ± 1.3 [XEN] vs. 2.0 ± 1.3 [Phaco + XEN]) to 0.8 ± 0.5 (0.8 ± 1.1 [XEN] vs. 0.8 ± 1.1 [Phaco + XEN]) (±60%; p < 0.001). Needling revision was performed in 39 eyes (49%), and 19.4% underwent reoperations.
At 5 years, XEN gel stent implantation achieved clinically significant IOP and medication reduction. The procedure carries a substantial rate of needling and re-operations.
Refraktive Ergebnisse nach der Implantation torischer Intraokularlinsen mit Hilfe des Zeiss Callisto Systems
Kenji Raemy (Effretikon | CH)
Mark Scherrer (Winterthur | CH)
Jörg E. Stürmer (Winterthur | CH)
Für Kataraktpatienten mit Astigmatismus ist das Einsetzen von torischen Intraokularlinsen (IOL) eine sichere und effektive Methode, um eine Emmetropie zu erzielen. Dabei ist die exakte Ausrichtung der Linse entlang des berechneten Meridians essentiell für eine effektive Astigmatismus-Korrektur. Das Ziel dieser Studie ist die Auswertung der Daten mittels deskriptiver Statistik. Der primäre Fokus liegt dabei auf den refraktiven Ergebnissen und somit der Überprüfung der Ausrichtungsgenauigkeit von torischen IOL mit dem Zeiss Callisto System.
Patienten und Methoden
Für die Studie wurden insgesamt 106 Augen von 72 Patienten ausgewertet, welche zwischen Januar 2019 bis Dezember 2020 eine Kataraktoperation mit Implantation einer torischen IOL im Kantonsspital Winterthur (KSW) erhalten haben. Die präoperative Biometrie und intraoperative Markierung der Implantationsachse wurde mittels Zeiss Callisto System durchgeführt. Die postoperativen Kontrollen erfolgten nach einem Tag, nach einer Woche und nach 4 Wochen im KSW oder beim zuweisenden Augenarzt. Für die Auswertung wurden nur die Daten der 4-wöchigen Kontrolle verwendet.
In 64 Augen (60%) wurde eine Zeiss AT Torbi 709 M und MP sowie in 42 Augen (40%) eine PhysIOL Ankoris toric yellow IOL implantiert. Bei 46 Augen wurde der unkorrigierte postoperative Visus nicht erfasst. Von den übrigen 60 Augen beträgt der mediane unkorrigierte postoperative Visus 0.9 (0.8 bis 1.0 [IQR]). Dabei konnte bei 48% der Augen eine Emmetropie und bei 92% ein Visus ≥ 0.6 erzielt werden. Der postoperative Zylinder beträgt im Median 0.5 Dioptrien (0.25 bis 0.75). Der Median des postoperativen Zylinders abzüglich des Zylinders der Zielrefraktion ist 0.33 (0.17 bis 0.64).
Das Zeiss Callisto Systems ist eine effektive Methode mit sehr guten klinischen Ergebnissen, um torische Intraokularlinsen entlang der Implantationsachse auszurichten.
325° Arch-Length Intracorneal Ring Implantation Strain Maps Visualized With New Optical Coherence Elastography
Emilio A. Torres-Netto (Zürich | CH)
Purpose: The objective of this study was to record the axial corneal strain field in the cornea that resulted directly after creating a stromal tunnel as well as after implanting an intracorneal ring segment (ICRS).
Setting: Swiss federal institute of technology
Methods: Freshly enucleated porcine eyes were obtained and assigned either to ICRS implantation, to tunnel creation only or to virgin control. Immediately after manual tunnel creation and ICRS positioning, respectively, the entire eye globe was mounted within a customized holder and intraocular pressure (IOP) was adjusted to 15 mmHg. Then, IOP was increased in steps of 1 mmHg to 20 mmHg and decreased again. At each step, an optical coherence tomography volume scan was recorded. Displacements between subsequent scans were retrieved using a vector-based phase difference method. The induced corneal strain in axial direction was determined by taking the axial gradient. In addition, corneal surface was detected and sagittal curvature maps computed.
Results: Corneal tissue presented a localized compressive strain in the direct vicinity of the stromal tunnel, which was independent of the sign of IOP change. The central and peripheral (exterior to the ICRS) cornea demonstrated compressive strains upon IOP increase, and tensile strains upon IOP decrease. ICRS induced an annular shaped tensile strain at its inner border, particularly during IOP increase. The compressive strains close to the tunnel remained with ICRS implantation. Corneal curvature changes were limited to the corneal regions subjected to strain.
Conclusions: Tunnel creation and ICRS implantation induce localized strains in cornea regions that coincide with those of refractive changes[ETN1] [SK2] , suggesting that corneal strain and curvature are directly related. Studying corneal strain in response to surgical intervention may provide new insights on underlying working principles.