Assessing Corneal Endothelial Damage Using Terahertz Time-Domain Spectroscopy and Support Vector Machines.

The endothelial layer of the cornea plays a critical role in regulating its hydration by actively controlling fluid intake in the tissue via transporting the excess fluid out to the aqueous humor. A damaged corneal endothelial layer leads to perturbations in tissue hydration and edema, which can impact corneal transparency and visual acuity. We utilized a non-contact terahertz (THz) scanner designed for imaging spherical targets to discriminate between ex vivo corneal samples with intact and damaged endothelial layers. To create varying grades of corneal edema, the intraocular pressures of the whole porcine eye globe samples (n = 19) were increased to either 25, 35 or 45 mmHg for 4 h before returning to normal pressure levels at 15 mmHg for the remaining 4 h. Changes in tissue hydration were assessed by differences in spectral slopes between 0.4 and 0.8 THz. Our results indicate that the THz response of the corneal samples can vary according to the differences in the endothelial cell density, as determined by SEM imaging. We show that this spectroscopic difference is statistically significant and can be used to assess the intactness of the endothelial layer. These results demonstrate that THz can noninvasively assess the corneal endothelium and provide valuable complimentary information for the study and diagnosis of corneal diseases that perturb the tissue hydration.

Comparison of Comorbid Associations and Ocular Complications in Herpes Simplex and Zoster Keratitis.

A retrospective chart review examined adult patients with herpes simplex (HSV) and zoster (HZO) keratitis at a single institution. Patients who suffered a poor outcome (defined as visually significant corneal scarring, neurotrophic keratitis, secondary glaucoma, or requiring corneal surgery) were identified and each outcome type was analyzed in relation to age, sex, diabetes mellitus, immunosuppression, and a prior history of ≥2 ocular procedures.Advanced age, diabetes mellitus, and a prior history of ≥2 ocular procedures may be risk factors for poor outcomes in HSV, but not HZO, keratitis. In HSV, older age and DM were specifically associated with visually significant corneal scarring, while older age and male sex were associated with secondary glaucoma. Future prospective studies are warranted to determine the ideal management (including prophylaxis) in patients with these characteristics.

Non-contact terahertz spectroscopic measurement of the intraocular pressure through corneal hydration mapping.

Elevated intraocular pressure (IOP) results in endothelial layer damage that can induce corneal hydration perturbations. We investigated the potential of terahertz spectroscopy in measuring the IOP levels through mapping corneal water content. We controlled the IOP levels in ex vivo rabbit and porcine eye samples while monitoring the change in corneal hydration using a terahertz time-domain spectroscopy (THz-TDS) scanner. Our results showed a statistically significant increase in the THz reflectivity between 0.4 and 0.6 THz corresponding to the increase in the IOP. Endothelial layer damage was confirmed using scanning electron microscopy (SEM) of the corneal biopsy samples. Our empirical results indicate that the THz-TDS can be used to track IOP levels through the changes in corneal hydration.

Observational Clinical Studies of Human Lens Transparency Using the Vision Index Pen.

PURPOSE: Preventing or delaying the onset of presbyopia and cataract formation remains a challenge. The goal of this study was to establish the utility of the Vision Index Pen (VIP), designed to measure in vivo dynamic light scattering (DLS) from the crystalline lens, in the detection of early cataract or loss of accommodation and to show reproducibility through trials at two independent sites. The gradual loss of transparency of the lens was characterized by the lens crystallin aggregation index (LCX) derived from measured DLS data. METHODS: Volunteers in different age groups participated in two independently operated observational clinical studies. All subjects underwent a detailed eye exam and VIP measurement of the intensity correlation of the backscattered light from the lens. RESULTS: LCX values extracted from DLS data show strong correlation with the aging lens, ranging from 20 at the age of 20 years to over 150 at 60 years. Quantitatively significant changes in the LCX value occur from 35 years to 55 years. LCX values were found to correlate with the loss of accommodation (correlation of -0.563 with P < 0.001) and with published data regarding the change in relative lens resistance with age. CONCLUSIONS: Results from two independent observational clinical trials have confirmed the repeatability and reproducibility of the VIP diagnostic device as a viable clinical tool for tracking localized macromolecular changes taking place in the aging lens. Detection of early changes in the crystalline lens can be useful in developing patient-specific prediction models, which can be used to screen patients who may benefit from early therapeutic interventions for delaying the onset of presbyopia and cataract growth. TRANSLATIONAL RELEVANCE: The VIP diagnostic device provides in vivo access to the human lens, enabling characterization of the unfolding and decomposition of long-lived macromolecules.

Refractive outcomes of phacoemulsification after pars plana vitrectomy using traditional and new intraocular lens calculation formulas.

PURPOSE: To evaluate refractive outcomes of cataract surgery in previously vitrectomized eyes and compare the accuracy of intraocular lens (IOL) calculation formulas in this population. SETTING: Stony Brook University Hospital, Stony Brook, New York, USA. DESIGN: Retrospective case series. METHODS: All electronic medical records of patients who had phacoemulsification from 2013 to 2017 were reviewed. Patients who had previously had pars plana vitrectomy in the same eye were selected. Patients with a history of refractive surgery, silicone oil in the eye, or other factors preventing accurate IOL power calculation were excluded. RESULTS: The mean postoperative spherical equivalent was -0.16 diopter (D) ± 0.81 (SD) (n = 61). The mean prediction errors were 0.30 ± 0.82 D, -0.09 ± 0.76 D, 0.23 ± 0.76 D, 0.25 ± 0.81 D, 0.04 ± 0.85 D, 0.30 ± 0.82 D, 0.33 ± 0.79 D, and 0.45 ± 0.80 D with the Holladay 1, Wang/Koch (WKA) adjusted Holladay 1 (n = 14), Holladay 2 (n = 48), SRK/T, WKA SRK/T (n = 14), Hill-Radial Basis Function (n = 50), and Ladas formulas, respectively. The formula with the highest percentage of predictions within ±0.50 D of the postoperative outcome was the Holladay 2 (60.42%). Statistically significant differences between the predicted and actual refractive outcomes were found with all formulas (P < .05) except the WKA Holladay and WKA SRK/T. Intraclass correlation showed low repeatability (<0.50) for all formulas. CONCLUSIONS: Refractive outcomes after cataract extraction in vitrectomized patients can be variable and more hyperopic than the predicted outcomes using traditional and newer IOL calculation methods. Thus, predicting refractive outcomes in this population is challenging, and patients should be counseled accordingly.

A review of teaching methods and outcomes of resident phacoemulsification.

Cataract surgery with phacoemulsification is a challenging procedure for surgeons in training to learn to perform safely, efficiently, and effectively. We review the auxiliary learning tools outside the operating room that residency programs have incorporated into their curriculum to improve surgical skills, including wet laboratory and surgical simulators. We then discuss different methods of teaching cataract surgery in the operating room. Our goal is to define a learning curve for cataract surgery. We demonstrate that complication rates decline significantly after a resident performs an average of 70 cases. We summarize the reported incidence and risk factors for complications in resident-performed cataract surgery to help identify cases that require a higher level of skill to improve visual outcomes. We suggest that future studies include details on preoperative comorbidities, risk stratification, resident skill level, and frequency of takeover by attending.

Improved refractive outcomes of postgraduate year 4 cataract surgery after implementing a stepwise biometry lecture series reinforced by self-assessment at a teaching program.

PURPOSE: To determine whether a structured biometry course improves refractive outcomes of resident phacoemulsification. SETTING: Northeast Veterans Administration Hospital, Northport, New York, USA. DESIGN: Retrospective case study. METHODS: Phacoemulsification surgeries performed by residents before and after a biometry curriculum were reviewed. The inclusion criterion was phacoemulsification performed by residents. Patients with fewer than 3 months of follow-up were excluded. The main outcome measure-the mean absolute difference between the target and final refraction-was compared using a linear mixed model. RESULTS: Phacoemulsification surgeries performed by 4 residents before (n = 223) and by 4 residents after (n = 242) a biometry curriculum was implemented were reviewed. All measured preoperative factors were similar in both groups, including age, visual acuity, axial length, steep and flat keratometry values, astigmatism, anterior chamber depth, and lens thickness. Before the biometry course was instituted, 10% of patients had a mean absolute difference of less than 0.25 diopter (D); the percentage was 35% afterward. The mean absolute difference was less than 0.50 D in 40% before the curriculum was initiated and 70% after. The mean absolute difference was less than 1.00 D in 75% before the curriculum was initiated versus 94% after (all P < .05). The corrected distance visual acuities were similar in both groups, with 83% and 80%, respectively, having an acuity of at least 20/25 (P > .05). CONCLUSION: Residents' refractive predictions significantly improved after a formal biometry curriculum, showing that improvements in resident surgical outcomes are possible with structured curriculums reinforcing outcome measures. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.

Early-onset methicillin-resistant Staphylococcus aureus keratitis and late-onset infectious keratitis in astigmatic keratotomy incision following femtosecond laser-assisted cataract surgery.

UNLABELLED: A 79-year-old woman had uneventful femtosecond laser-assisted cataract surgery including paired laser astigmatic keratotomies (AKs) in the right eye. Three weeks postoperatively, a corneal infiltrate developed in the superotemporal AK incision. Cultures grew methicillin-resistant Staphylococcus aureus. The infection was treated with topical fortified vancomycin and tobramycin; full resolution required several months of therapy. Five months after cataract surgery, the patient presented with a second stromal infiltrate, also in the superotemporal AK incision. Despite negative cultures, the infiltrate resolved quickly on a short course of broad-spectrum fortified antibiotics. At 6 months, the corrected distance visual acuity was 20/30. This case demonstrates that infectious keratitis can occur following uneventful femtosecond laser-assisted AK performed concurrently with cataract surgery. We reviewed the literature on infectious keratitis following refractive keratotomy and femtosecond laser-assisted procedures. Several recommendations to prevent these infections are proposed. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

A 31-year-old man with bilateral blurry vision and floaters.

We report a case of bilateral multifocal retinochoroiditis and bilateral optic disc edema in a patient with cat-scratch disease from Bartonella henselae. The patient initially had negative serologic testing. Repeat testing showed a markedly increased IgG and IgM convalescent titer and the development of a branch retinal artery and vein occlusion. In patients for whom there is a high clinical suspicion of cat-scratch disease, a convalescent titer should be obtained 2-3 weeks following a negative initial result.

Trabeculectomy for traumatic hyphema in sickle cell trait.

A case report of a traumatic hyphema in a patient with sickle cell trait is presented. A review of the published literature in PubMed was performed and medical management strategies and surgical treatment indications for traumatic hyphema are discussed. We support the case for temporary trabeculectomy in patients with traumatic hyphema and sickle cell disease.

The use of endoscopic cyclophotocoagulation for moderate to advanced glaucoma.

Endoscopic Cyclophotocoagulation (ECP) is a glaucoma surgery designed to reduce the intraocular pressure (IOP) by partially ablating the ciliary processes to decrease aqueous humour production and secretion. The aim of this paper is to review the literature regarding the background, indications and results of the surgery. Although there are case reports of visually devastating complications, including persistent hypotony and phthisis, the use of ECP is often reported in eyes with advanced diseases. When compared with both trabeculectomy and aqueous shunt implantation, the visual outcomes were better with ECP while the IOP outcomes were very similar. The evidence supports ECP as a very effective surgical option in recalcitrant glaucoma while some evidence supports its safety for use as a primary procedure.

A modified ultrasound-guided surgical technique for the management of the uveal effusion syndrome in patients with normal axial length and scleral thickness.

PURPOSE: The purpose of this study was to describe a modified surgical technique for the management of the uveal effusion syndrome (UES). METHODS: A consecutive interventional case series of six eyes with UES is reported. The diagnosis of the UES was based on detailed ophthalmic examination, fluorescein angiography, B-scan ultrasonography, biometry, and magnetic resonance imaging. All eyes underwent an ultrasound-guided placement of the sclerostomies subjacent to the area of maximal choroidal swelling using a scleral punch without scleral flaps or vortex vein decompression. RESULTS: All patients were men with a mean age of 53 years. The mean postoperative follow-up was 16.25 months. Five eyes had normal axial lengths (22.54-23.05 mm) by ultrasound and normal sclera thickness on magnetic resonance imaging. One eye had a shorter axial length (21.65 mm) and mild scleral thickening on magnetic resonance imaging. All six eyes had anterior peripheral choroidal swelling. Three eyes had associated serous retinal detachment, and three eyes had acute appositional angles. After surgery, five eyes had total resolution of the peripheral choroidal swelling and retinal detachment or normalization of the angle. One eye had partial resolution of the retinal detachment. Of the three eyes with retinal detachment, two eyes experienced improvement in visual acuity after surgery. No complications were noted. CONCLUSION: This modified ultrasound-guided surgical technique for sclerostomy placement seems to be effective in the management of the UES, including eyes with normal axial length and scleral thickness, a subset of the UES that has been previously reported not to respond to surgery.

Corneal changes in ectrodactyly-ectodermal dysplasia-cleft lip and palate syndrome: case series and literature review.

The aim of this study is to describe the corneal changes in three unrelated patients with ectrodactyly-ectodermal dysplasia-cleft lip and palate (EEC) syndrome and review the literature on the possible etiology and clinical presentation of similar cases. Case 1 is an 18-year-old female with cleft lip and palate, syndactyly, and bilateral corneal pannus superiorly and inferiorly. She was initially diagnosed and treated as herpes simplex virus keratitis. Case 2 is a 3-year-old female born with cleft lip and palate, absent radial digits in both hands, and bilateral lacrimal stenosis. She developed progressive stromal scarring and neovascularization in both eyes. Her cornea perforated after developing infectious ulceration. Case 3 is a 49-year-old male with cleft palate, claw-hand deformities, absent meibomian glands and lacrimal duct, right ankyloblepharon, and a superior wedge-shaped opacity in the left cornea. The clinical findings demonstrated the different spectrum of keratopathy seen in patients with EEC. All patients were treated medically and without any surgical intervention. Limbal stem cell deficiency (LSCD) is presumed to be the cause in all three cases. Corneal changes in EEC can have variable presentation. LSCD seems to be the etiology of such keratopathy. Recurrent infection from lacrimal drainage obstruction and tear film instability are other risk factors for disease severity and progression.

Descemet membrane detachment among siblings: role of anatomic and familial predisposition.

PURPOSE: To describe 2 siblings with Descemet membrane detachment (DMD) after intraocular surgery and discuss the potential role of anatomic and familial predisposition. METHOD: Case reports. RESULTS: A 64-year-old woman had bilateral DMDs after trabeculectomy in her right eye and during combined cataract extraction and trabeculectomy in her left eye. Both were successfully treated with intracameral sulfur hexafluoride gas injections. Her older sister also developed DMD in her left eye that was noted after uncomplicated cataract surgery. Slit-lamp examination of her unoperated eye revealed irregular Descemet membrane with thickening and a wavy configuration, suggesting an intrinsic corneal abnormality. No endothelial guttae or polymorphous changes were noted. Intracameral sulfur hexafluoride gas injection was attempted to reattach the Descemet membrane but was unsuccessful. The patient then underwent Descemet stripping endothelial keratoplasty with excellent postoperative results. CONCLUSIONS: Predisposition to DMD among relatives may be linked to hereditary morphological abnormalities present in their corneas.

Optical coherence tomography findings in autoimmune retinopathy.

PURPOSE: To report optical coherence tomography (OCT) features of patients with autoimmune retinopathy. DESIGN: Consecutive case series. METHOD: Eight patients who presented with unexplained loss of central vision, visual field defects, and/or photopsia were diagnosed with autoimmune retinopathy based on clinical features, electroretinogram (ERG) findings, and serum antiretinal antibody analysis. All patients underwent OCT testing of the macula and nerve fiber layer (NFL). RESULTS: Outer retinal abnormalities and/or decreased macular thickness on OCT were seen in all patients. Macular OCT showed reduced central macular and foveal thicknesses in 6 patients (mean thickness 143±30 µm and 131±29 µm respectively). In all but 1 patient, loss of the photoreceptor layer or disruption of the photoreceptor outer and inner segment junction was noted. Three patients showed only mild to moderate focal NFL loss. CONCLUSIONS: Retinal atrophy and reduced macular thickness on OCT are predominant features in patients with autoimmune retinopathy. OCT provides objective measures of retinal damage and may offer clues toward understanding the mechanism of visual dysfunction and the diagnosis of autoimmune retinopathy.