A Review of Antimicrobial Therapy for Infectious Uveitis of the Posterior Segment

Ahmed B Sallam, Kyle A. Kirkland, Richard Barry, Mohamed Kamel Soliman, Tayyeba K Ali, Sue Lightman

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 140-155

Treatment of infectious posterior uveitis represents a therapeutic challenge for ophthalmologists. The eye is a privileged site, maintained by blood ocular barriers, which limits penetration of systemic antimicrobials into the posterior segment. In addition, topical and subconjunctival therapies are incapable of producing sufficient drug concentrations, intraocularly. Posterior infectious uveitis can be caused by bacteria, virus, fungi, or protozoa. Mode of treatment varies greatly based on the infectious etiology. Certain drugs have advantages over others in the treatment of infectious uveitis. Topical and systemic therapies are often employed in the treatment of ocular infection, yet the route of treatment can have limitations based on penetration, concentration, and duration. The introduction of intravitreal antimicrobial therapy has advanced the management of intraocular infections. Being able to bypass blood-ocular barriers allows high drug concentrations to be delivered directly to the posterior segment with minimal systemic absorption. However, because the difference between the therapeutic and the toxic doses of some antimicrobial drugs falls within a narrow concentration range, intravitreal therapy could be associated with ocular toxicity risks.  In many cases of infectious uveitis, combination of intravitreal and systemic therapies are necessary. In this comprehensive review, the authors aimed at reviewing clinically relevant data regarding intraocular and systemic antimicrobial therapy for posterior segment infectious uveitis. The review also discussed the evolving trends in intraocular treatment, and elaborated on antibiotic pharmacokinetics and pharmacodynamics, efficacy, and adverse effects.

The Association of Serum Leptin Level and Anthropometric Measures With the Severity of Diabetic Retinopathy in Type 2 Diabetes Mellitus

Mehrdad Afarid, Adel Attarzadeh, Mohsen Farvardin, Hossein Ashraf

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 156-162

This study was performed to determine the association amongst serum leptin level and anthropometric measures with the severity of Diabetic Retinopathy (DR) in subjects with type 2 Diabetes Mellitus (DM). This case-controlled study was conducted within a one-year period, during year 2016, at outpatient retina ophthalmology clinics of Shiraz, southern Iran. Eighty-three patients with type 2 DM, referring for ophthalmoscopy evaluation, were included. Anthropometric measures, serum leptin level, and baseline laboratory assessment was performed for all subjects. Patients were categorized as group 1, consisting of patients with severe Non-Proliferative Diabetic Retinopathy (severe NPDR) and Proliferative Diabetic Retinopathy (PDR) (n = 44), and group 2, consisting of patients without Diabetic Retinopathy (no DR) or mild/moderate NPDR (n = 39). The serum leptin level and anthropometric measures were compared between the two study groups. The correlation between these variables was also assessed. The mean age of the participants was 59.3 ± 6.9 years old. The two study groups were comparable regarding baseline characteristics. Cases of group 1 had significantly higher Erythrocyte Sedimentation Rate (ESR) (P = 0.049) and Systolic Blood Pressure (P = 0.025) when compared with those of group 2. The serum level of leptin was found to be significantly higher in cases of group 1 when compared to those of group 2 (P = 0.003). However, anthropometric measures, including Body Mass Index (BMI) (P = 0.167), Body Adiposity Index (BAI) (P = 0.061), and Waist to Hip Ratio (WHR) (P = 0.220) were comparable between the two study groups. Serum leptin level was positively correlated with BMI (r = 0.819; P < 0.001) and BAI (r = 0.630; P < 0.001) in group 1. Increased serum levels of leptin were associated with advanced stages of DR in subjects with type 2 DM. Serum leptin level might be a better indicator of the effects of obesity on DR, compared to anthropometric measures (BAI or BMI).

Repeatability and Reproducibility of Peripapillary Choroidal Thickness Using a Medical Image-Processing Software

Pedro Simoes, Pedro Silva, Miguel Cordeiro, Joao Costa

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 163-168

Although choroid has been shown to have a vital role in the pathophysiology of many ocular diseases, its role in the pathogenesis of several other conditions remains uncertain. The authors propose a novel methodology to establish a more accurate Peripapillary Choroidal Thickness (PPCT), using an image-processing software. This study sought to evaluate the reproducibility and repeatability of PPCT evaluation with ImageJ software in healthy volunteers. Forty-eight eyes of 24 volunteers were subjected to PPCT area determination, after imaging acquisition and recording with Spectral-domain Optical Coherence Tomography (SD-OCT) Heidelberg Spectralis®, during two different sessions, by two blinded assessors. The age of the subjects was 29.2 ± 4.5 years (mean ± SD). The Coefï¬cient of Repeatability (CR) average measurements of PPCT area was 17.06 mm2 and 9.48 mm2 correspondingly, for the ï¬rst and second examiners. Intra-class Correlation Coefï¬cient (ICC) was 0.994 (95% CI 0.989 to 0.997) and 0.998 (95% CI 0.997 to 0.999). Inter-observer Concordance Correlation Coefï¬cient (CCC) was 0.998 (95% CI 0.996 to 0.999) for both examiners. Intra-observer CCC ranged from 0.997 (95% CI 0.996 to 0.999) to 0.998 (95% CI 0.997 to 0.999), correspondingly, for the first and second examiners. The PPCT quantification by means of the proposed methodology showed good inter- and intra-observer agreement for both operators, indicating feasibility and good reproducibility of the proposed methodology. This approach might be used in different clinical settings and potentially contributes to elucidation of the choroid role in ocular pathology.

Intravitreal Dexamethasone Implant in the Treatment of Non-Infectious Uveitic Macular Edema

Omer Karti, Ali Osman Saatci

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 169-175

Macular Edema (ME) is a common complication, leading to severe vision loss in patients with Non-Infectious Uveitis (NIU). The treatment of uveitic ME is still very challenging for many ophthalmologists. Various agents, such as corticosteroids, anti-vascular endothelial growth factors, and immune-modulators, have been used for combatting uveitic ME. However, there is not enough evidence to support the efficacy of any of these agents. Intravitreal Dexamethasone Implant (IDI) (Ozurdex; Allergan Inc, Irvine, CA) is a widely administered corticosteroid for the long-term management of uveitic ME in certain cases. Ophthalmic implant is made up of a biodegradable copolymer that contains glycolic acid and lactic acid. Recent studies have demonstrated that dexamethasone implant effectively improves uveitis-related ME. The authors suggest that this effect could be sustained for at least six months with close monitoring and re-treatment, as needed. The current study reviewed major clinical studies about IDI in eyes with NIU and briefly overviewed their results.

The Effect of Intravitreal Bevacizumab on Central Serous Chorioretinopathy

Alireza Maleki, Zahra Nezamdust, Amirmasoud Salari, Seyed Sajad Ahmadi, Hamideh Sabbaghi, Omid Bagherzadeh, Alireza Ataollahi, Mehdi Yaseri

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 176-182

The aim of this study was to investigate the efficacy of Intravitreal Injection of Bevacizumab (IVB) in patients with Central Serous Chorioretinopathy (CSC) compared to the control group, after four months of injection. In this study, 30 eyes of 30 patients with CSC, who were in the age range of 23 to 50 years old (70% male subject) were included. Eligible patients were randomly allocated to the intervention (n = 15) and control groups (n = 15). Patients in the intervention group received a single dose injection of bevacizumab (1.25 mg in 0.05 mL), while patients in the control group were followed-up during the same time interval, without any medical interventions. Corrected Distance Visual Acuity (CDVA) and Central Macular Thickness (CMT) were evaluated as the primary outcome measures at the four-month follow-up. There was no statistically significant difference between the intervention and control groups regarding their baseline characteristics. Corrected Distance Visual Acuity was improved significantly in the intervention group (P < 0.001), while this improvement was not observed in the control group. Furthermore, greater improvement of CDVA was detected in the IVB group compared to the patients without injection (P = 0.018). The CMT findings were in line with CDVA changes in both groups, revealing a significant reduction of CMT only in the intervention group (P < 0.001). Also, thinner central retina was found in the intervention group compared to the comparison group, at the four-month follow-up (P < 0.001). Based on the findings, bevacizumab could be effective for improvement of both anatomical and functional outcomes in patients with CSC.

Optical Rehabilitation of a Patient with Keratoconus and Nystagmus

Dorcas K. Tsang, Frank Spors, Jie Shen, Lance E. McNaughton, Donald J. Egan

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 183-189

Keratoconus is a progressive corneal disease characterized by bilateral yet usually asymmetric thinning of the cornea with an onset typically in teenage years.  While it often presents as an isolated condition, keratoconus may also be associated with many systemic and/or ocular diseases, such as connective tissue and chromosomal disorders.  Its association with nystagmus has been described in Leber’s congenital amaurosis, where patients also exhibit abnormal pupillary responses, early-onset retinal dystrophy, mental developmental delays, and eventual blindness.  The case described here, however, was a high-functioning teenager with keratoconus and infantile nystagmus, and oscillopsia on left gaze and a compensatory head turn to the patient’s left. The initial distance visual acuities of 20/60 and 20/150 in the right and left eye, respectively improved to 20/25 and 20/40 by the use of corneal rigid gas permeable contact lenses. In addition, the patient’s neck strain and overall gait were eased by yoked prism spectacles.

Micropulse Laser for Persistent Sub-Retinal Fluid in a Patient Previously Treated for Rhegmatogenous Retinal Detachment

Gennady Landa

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 4 (2018), 1 December 2018 , Page 190-194

The purpose of this study was to report the resolution of persistent Sub-Retinal Fluid (SRF) induced by subthreshold micropulse laser treatment in a patient, formerly treated for rhegmatogenous retinal detachment by retinal pneumopexy. The case was a 41-year-old male, who initially presented macula-splitting rhegmatogenous retinal detachment and corrected distance visual acuity of 20/40 in his left eye. He was treated by retinal pneumopexy and laser retinopexy. Retina was flattened and vision improved to 20/30. However, the subretinal fluid (SRF) under the fovea was persistently observed on repeated retinal exams. Fourteen months after the initial pneumopexy, subthreshold micropulse laser was applied to cover the entire area of the SRF. The improvement started two weeks afterwards and the SRF completely resolved within four months after the application of micropulse laser. Corrected distance visual acuity improved from 20/30 to 20/20, accompanied by marked improvement in patient’s complaints on visual blurriness. The patient was followed up for three years and no recurrence of SRF was noted. The findings of this report indicate that subthreshold micropulse laser may serve as a therapeutic option for persistent SRF, which may be observed after successful retinal detachment repair.