|Year : 2018 | Volume
| Issue : 1 | Page : 51-53
Shruti Nishanth, Murali Ariga
Department of Paediatric Ophthalmology and Strabismus, M. N. Eye Hospital, Chennai, Tamil Nadu, India
|Date of Web Publication||4-Jun-2018|
Dr. Shruti Nishanth
M. N. Eye Hospital, Chennai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nishanth S, Ariga M. Journal Scan. TNOA J Ophthalmic Sci Res 2018;56:51-3
| Recent Clinically Relevant Highlights from the Diabetic Retinopathy Clinical Research Network|| |
Krick TW, Bressler NM. Recent clinically relevant highlights from the diabetic retinopathy clinical research network. Curr Opin Ophthalmol 2018;29:199-205.
Introduction: The purpose of this review is to present some recent clinically relevant highlights from the Diabetic Retinopathy Clinical Research Network, paying particular attention to results published within the past year that may help guide clinical management of diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR). Choice of Antivascular Endothelial Growth Factor Agent: Aflibercept, bevacizumab, and ranibizumab are intravitreous antivascular endothelial growth factor (anti-VEGF) agents widely used for the treatment of DME. Aflibercept has more favorable visual acuity and anatomical outcomes among eyes with worse visual acuity or PDR at baseline compared with bevacizumab or ranibizumab. Outcome of Eyes with Persistent Diabetic Macular Edema Despite Repeated Intravitreous Antivascular Endothelial Growth Factor Injections: Repeated injections of anti-VEGF after six doses may not resolve DME but prevent worsening. Repeat injections are suggested if there is a change in optical coherence tomography central subfield thickness or visual acuity. Even in chronic DME for >2 years, there is an improvement of visual acuity seen as compared to baseline. The effect of adding intravitreous corticosteroids to anti-VEGFs for persistent DME was better visual acuity in pseudophakic eyes while the same showed a higher risk of developing cataracts in phakic eyes, thereby reducing visual acuity. Intravitreous injections proved to be an alternative to platelet-rich plasma (PRP) for PDR at least through 2 years. Close monitoring is required even after full PRP. Supplemental PRP and vitrectomy may be required if PDR worsens. There are many other benefits of ranibizumab versus PRP including better peripheral vision, fewer vitrectomies, and decreased risk of developing DME. With respect to cost of therapy, ranibizumab is cost-effective for PDR when the patient also has vision-impairing center involving DME, but not when there is no concurrent DME.
For diabetic retinopathy with diabetic macular edema, intravitreous anti-vascular endothelial growth factor injections seem to yield good results of which aflibercept seems to be the most promising one while ranibizumab is the most cost-effective. Adding steroids may not improve visual acuity in phakic eyes. The future of diabetic retinopathy may lie in anti-vascular endothelial growth factor therapy with platelet-rich plasma becoming an alternative.
| Preoperative Aqueous Cytokine Levels are Associated with A Rapid Reduction in Endothelial Cells After Penetrating Keratoplasty|| |
Yagi-Yaguchi Y, Yamaguchi T, Higa K, Suzuki T, Yazu H, Aketa N, et al. Preoperative aqueous cytokine levels are associated with a rapid reduction in endothelial cells after penetrating keratoplasty. Am J Ophthalmol 2017;181:166-73.
This prospective study aims to observe the effects of inflammatory cytokines in the aqueous humor (AqH), as a risk factor for endothelial cell loss in patients undergoing penetrating keratoplasty (PKP). Previous studies have shown indirectly that pro-inflammatory cytokines induced the apoptosis of corneal endothelial cells. In addition, Endothelial cell densities (ECDs) are lower in eyes with a history of uveitis, suggesting that inflammatory factors in the AqH directly influence endothelial cell loss. They studied 70 eyes (37 study eyes underwent PKP, 30 control eyes– underwent uneventful cataract surgery). The AqH samples were obtained under sterile conditions at the beginning of surgery with a 27G needle after retrobulbar anesthesia in corneal transplantation or topical anesthesia in cataract surgery. They classified the PKP patients into two groups based on their ECD 6 months after PKP; Group 1 included 13 eyes where ECDs were <1200 cells/mm 2 and Group 2 included 24 eyes where ECDs were ≥1200 cells/mm 2. They compared protein and cytokine levels between the groups. Results: Preoperative AqH protein levels were significantly higher in ECD Groups 1 and 2, compared to the control group. ECD at 6 months after PK was inversely correlated with preoperative AqH levels of interleukin 10 (IL-10), MCP-1 and interferon-gamma.
The AqH microenvironment may determine the endothelial cell prognosis after PKP. This gains relevance to ascertain whether preoperative steroid use prevents the rapid loss of endothelial cells after PKP by reducing inflammatory cytokine levels.
| A Method for Quantifying Limbal Stem Cell Niches Using Optical Coherence Tomography Imaging|| |
Haagdorens M, Behaegel J, Rozema J, Van Gerwen V, Michiels S, Ní Dhubhghaill S, et al. Amethod for quantifying limbal stem cell niches using OCT imaging. Br J Ophthalmol 2017;101:1250-5. Stem cell niches are highly organized three-dimensional (3D) structural units that provide a unique microenvironment to support stem cells in the human eye. They have been studied extensively with ultrahigh-Resolution optical coherence tomography (OCT), which is not commonly available in clinical practice. Hence, this study endeavors to use the more commercially available frequency domain-OCT (FD-OCT) (Optovue RTVue 100-2), as a technique to image the limbal stem cell niches. The superior and inferior limbal region of both the eyes of 50 healthy volunteers were imaged by FD-OCT. Images were processed and analyzed using the Matlab software R2011b (The MathWorks, Massachusetts, USA).In vitro immunofluorescent staining of a cadaveric donor, limbus was analyzed to correlate the presence of stem cells in the visualized structures. Results: Palisades of Vogt (POV) could be identified on the OCT scans of 97% of included limbal regions, while the visibility at slit-lamp examination was 73%. These data suggest that FD-OCT is a more reliable tool for the visualization of the POV. FD-OCT could successfully visualize limbal crypts, and fluorescent labeling confirmed the presence of stem cells in these structures. The mean palisade ridge width (ΔPR) and the mean interpalisade epithelial rete peg width (ΔERP) were both of the order of 72 μm, leading to a palisade density (PD) of about 7.4 palisades/mm. A significant difference in ΔPR, ΔERP, and PD was seen between the inferior and superior sides of the right eye and the superior sides of the left and right eye.
In vivo optical coherence tomography imaging is a safe and effective modality to image the limbus and can be used to visualize the palisades of Vogt. Targeted biopsies could improve cell yield for procedures such as simple limbal epithelial transplantation or cultivated limbal epithelial transplantation and also prevent the development of adverse events such as induced or iatrogenic limbal stem cell deficiency.
| Visual and Refractive Outcomes In Manual Versus Femtosecond Laser-Assisted Cataract Surgery|| |
Berk TA, Schlenker MB, Campos-Möller X, Pereira AM, Ahmed II. Visual and refractive outcomes in manual versus femtosecond laser-assisted cataract surgery: A single-center retrospective cohort analysis of 1838 eyes. Ophthalmology 2018. pii: S0161-6420(17) 33311-0.
This was one of the largest observational cohort studies done on this subject so far. It was a retrospective study of 1838 eyes of 1089 patients, with 883 eyes in the manual cataract surgery (MCS) group and 955 eyes in the femtosecond laser-assisted cataract surgery (FLACS) group. The surgeries were performed by five experienced cataract surgeons between 2012 and 2015. All eyes with significant retinal or corneal pathology, steep corneas, high hyperopes and myopes, and extremes of age were excluded. Results: Adjusted for potential confounders, the proportion of eyes that achieved an absolute error (AE) within 0.5 D at 3 weeks postoperative period was 78.8% in the MCS group and 82.6% in the FLACS group (odds ratio [OR] 1.28). The proportion of these eyes that achieved an AE within 0.25 D was 46.3% in the MCS group and 49.3% in the FLACS group (OR = 1.13). The proportion of these eyes that achieved an AE within 1.0 D was similar between the two groups. Relative advantages for FLACS were seen in eyes in male patients, right eyes, first cataract surgeries, nondiabetic patients, eyes with softer cataracts, worse preoperative corrected distance visual acuity (logMAR >0.20), ALs longer than 22 mm, anterior chambers >3.5 mm deep, patients targeted for distance, and non-toric intraocular lenses (IOLs) implanted. Eyes undergoing FLACS had more posterior capsular tears, radial anterior capsular tears and corneal edema. FLACS was also associated with more post-operative aphakia and suturing of primary corneal incision. The FLACS group also had a greater number of eyes that received postoperative laser treatment for posterior capsule opacification, as well as more eyes that later underwent laser refractive procedures and limbal-relaxing incisions. The limitations of this study are its retrospective nature, bias due to multiple surgeons, noncomparison of capsulotomy metrics, postoperative IOL position, and subjective quality of vision.
As concluded by this study and several others in the past, there was no statistically significant difference found between eyes undergoing femtosecond laser-assisted cataract surgery and eyes undergoing manual cataract surgery with respect to refractive and visual outcomes. Further studies are required to study the other parameters of comparison between these two techniques.
| Performance and Safety of A New Ab Interno Gelatin Stent in Refractory Glaucoma at 12 Months|| |
Grover DS, Flynn WJ, Bashford KP, Lewis RA, Duh YJ, Nangia RS, et al. Performance and safety of a new Ab interno gelatin stent in refractory glaucoma at 12 months. Am J Ophthalmol 2017;183:25-36.
In this prospective, multicenter, single-arm, open-label, pivotal study, a new Food and Drug Administration-approved Gelatin stent (XEN 45 Gel Stent; Allergan plc, Dublin, Ireland) were studied on 65 patients of refractory glaucoma. The stent is composed of gelatin material derived from porcine dermis, formed into a tube, and then cross-linked with glutaraldehyde. The inside diameter of the tube is approximately 45 μ, its outside diameter is approximately 150 μ, and it is approximately 6 mm long. The gelatin imparts hydrophilic properties that allow the tube to expand when hydrated by contact with aqueous fluid. This expansion of the outer diameter of the tube aids in keeping the gelatin stent in its intended location after surgical implantation with a preloaded injector. Eligible patients were >45 years of age and had refractory glaucoma, defined as prior failure of filtering/cilioablative procedure and/or uncontrolled intraocular pressure (IOP) on maximally tolerated medical therapy, with medicated IOP >20 and <35 mm Hg and visual field mean deviation <3 dB. Following subconjunctival pretreatment of the target area with mitomycin sponges for 2 min, the injector was advanced through a clear corneal incision from the opposite quadrant, across the anterior chamber using an ab interno approach. The needle tip was then advanced through the trabecular meshwork (under gonioscopic guidance) and sclera and was visualized as it exited the sclera into the subconjunctival space. The gelatin stent was then released in the subconjunctival space such that 2 mm was exposed on the subconjunctival side and 1 mm on the anterior chamber side. After implantation, the conjunctiva was closed using vicryl or nylon. Results: At 12 months, 75.4% reported >20% IOP lowering from baseline on the same or fewer medications. Mean IOP change from baseline was 9.1 mmHg at 12 months. Mean medication count decreased from 3.5 (baseline) to 1.7 (12 months). Adverse events included needling to remove adhesions in 21 patients, nonpersistent loss of best-corrected visual acuity, and transient hypotony (requiring no surgical intervention).
Ab interno placement of the gelatin stent offers a minimally invasive surgical alternative to patients with refractory glaucoma, with good control of IOP and relative ease of application.
| Accuracy of Intraocular Lens Calculation Formulas|| |
Melles RB, Holladay JT, Chang WJ. Accuracy of intraocular lens calculation formulas. Ophthalmology 2018;125:169-78.
This study was a prospective, multicenter trial that studied the effect of various intraocular lens (IOL) formulae in the postoperative refractive outcomes. The IOL formulae studied were Barrett Universal II, Hill radial basis function, Olsen, Haigis, Hoffer Q, Holladay and SRK/T. A total of 13,301 consecutive patients who underwent uncomplicated cataract surgery with implantation of the two types of IOLs (SN60WF or SA60AT) over 1 year were eligible. A total of 145 surgeons contributed cases, and surgery was performed by clear cornea temporal incision phacoemulsification. All patients were measured preoperatively with the Lenstar 900 (Haag-Streit AG, Koeniz, Switzerland). Manifest refraction was performed at a 1-month postoperative visit with an optometrist. Results: Between axial lengths of 23 and 25 mm, all seven formulae give results that are within 0.1 D of predicted spherical equivalent. Barrett had the lowest mean absolute prediction error for short eyes. Contrary to expectation, the Hoffer Q had the worst performance in short eyes for both IOL types. For long eyes, the Olsen and Barrett had the lowest mean absolute prediction error, and the Holladay 1 and Hoffer had the greatest. The SRK/T, in particular, is adversely affected by eyes that have flat or steep keratometry. Haigis is the formula most affected by variation in lens thickness.
Overall, the Barrett Universal II formula had the lowest prediction error for the two intraocular lens models studied and seems to provide reliable intraocular lens power over a wide range of axial length, keratometry, AC depth, and lens thickness.
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