The PEG-PCL-PEG Hydrogel as an Implanted Ophthalmic Delivery System after Glaucoma Filtration Surgery; a Pilot Study

Ribo Peng, Gang Qin, Xiabin Li, Hongbin Lv, Zhiyong Qian, Ling Yu

Medical hypothesis discovery and innovation in ophthalmology, Vol. 3 No. 1 (2014), 1 March 2014 , Page 3-8

Currently, filtration surgery has been considered as the most effective therapy for glaucoma; however, the scar formation in the surgical area may often lead to failure to the procedure. An implanted drug delivery system may provide localized and sustained release of a drug over an extended period. Poly (ethylene glycol)-poly (ε-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG, PECE) hydrogel has been successfully synthesized and determined as thermosensitive and biocompatible. In order to overcome the limitations of common local ophthalmic medications, we investigated the function of a self-assembled PECE hydrogel as an intracameral injection-implanted drug carrier to inhibit the formation of postoperative scarring. Following intraoperative administration bevacizumab-loaded hydrogel intracameral was injected into rabbit eyes; the status of the bleb and filtration fistula formed following the filtering surgery were also examined through pathologic evaluation. Due to the sustained release of bevacizumab from the hydrogel, neovascularization and scar formation were inhibited; moreover, there were no corneal abnormalities and other ocular tissue damage found in the rabbits. This suggests that the PECE hydrogel may be considered as the novel biomaterial with potential as a sustained release system in glaucoma filtering surgery. Further studies require in shedding the light on the subject.

Focal Laser Photocoagulation in Non-Center Involved Diabetic Macular Edema

Irfan Perente, Zeynep Alkin, Abdullah Ozkaya, Doukas Dardabounis, Tulin Aras Ogreden, Aristeidis Konstantinidis, Konstantinos Kyratzoglou, Ahmet Taylan Yazici

Medical hypothesis discovery and innovation in ophthalmology, Vol. 3 No. 1 (2014), 1 March 2014 , Page 9-16

This study was performed to evaluate the functional and anatomic outcomes of focal macular laser photocoagulation in eyes with non-center involved macular edema (non-CI ME). Forty-nine eyes of 43 patients with non-CI ME were included. Focal macular laser photocoagulation was conducted on twenty-nine eyes of 25 patients, while 20 eyes of 18 patients with non-CI ME were followed without treatment and served as the control group. Data relating to best corrected visual acuity (BCVA; Early Treatment Diabetic Retinopathy Study) and central subfield thickness (CST), inner zone thickness (IZT), outer zone thickness (OZT), and total macular volume (TMV) as determined by optical coherence tomography (OCT) were collected and compared between the groups. At 12 months, VA decreased by a mean of 0.4 letters in the treatment group and 3.3 letters in the control group (p=0.03). Gain in VA ≥5 letters was noted in 6 (21%) of the eyes in the treatment group versus 1 (5%) eye in the control group (p=0.12). At 12 months, average IZT decreased by 22.6 microns in the treatment group and increased by 10.9 microns in the control group (p<0.001). The treatment group revealed significant reduction in CST, average OZT, and TMV as compared to the control group at 12 months (all p<0.05).Generally, focal laser photocoagulation may have more favourable visual outcomes in this specific group of diabetic patients than does observation. In addition, focal laser treatment provided better outcomes with improvement in OCT parameters as compared to the control group.

Modified Middle Eastern Contrast Sensitivity Chart

Mohammad Bagher Hadavand, Fatemeh Heidary, Roghayeh Heidary, Reza Gharebaghi

Medical hypothesis discovery and innovation in ophthalmology, Vol. 3 No. 1 (2014), 1 March 2014 , Page 17-19

The contrast sensitivity test has been used to examine vision in different clinical circumstances. Moreover, as contrast sensitivity is affected by several ocular states, its measurement has been considered practically for monitoring and assessment of a wide range of visual functions, predicting vision related abilities, diagnosing several ophthalmic conditions, and evaluating many ocular disorders including glaucoma, cataracts, diabetic retinopathy, optic neuritis and age-related degeneration. The Pelli-Robson standard chart has been translated and modified using Persian-Arabic characters since illiterates and children in the Middle East, Central Asia, and Africa are more likely to distinguish Arabic characters instead of English ones. The translation of these characters is expected to have more precise results, thereby improving the test’s validity and provide early diagnoses of ocular problems. This manuscript is focused on conceptions relating to the project. Further studies are required to evaluate the sensitivity, specificity, and reliability of the revised chart to best compare it to the standard Pelli-Robson one.

The Management of Patients with Cataracts and Medically Uncontrolled Glaucoma

Rahat Husain

Medical hypothesis discovery and innovation in ophthalmology, Vol. 3 No. 1 (2014), 1 March 2014 , Page 20-30

Trabeculectomy surgery has been shown to lower intraocular pressure and is the most commonly performed glaucoma procedure worldwide. However, giving a patient a ‘bleb for life’ is not without consequences and the failure of trabeculectomy to control IOP in the long term is well documented. In some instances, such as in patients with exfoliative glaucoma or primary angle closure glaucoma, cataract surgery alone can often lower IOP to acceptable levels. Cataract surgery in these instances can sometimes be combined with procedures such as goniosynechialysis or endoscopic cyclophotocoagulation which may provide additional IOP lowering. Such surgery has the distinct advantage of avoiding conjunctival incisions, so that subsequent trabeculectomy, if required, is more likely to be successful. In any case, it is preferable to perform trabeculectomy in a pseudophakic eye for several reasons. If trabeculectomy is performed in a phakic eye, patients should be warned that subsequent cataract is likely and if cataract surgery is performed it is preferable to wait at least a year or more after the trabeculectomy to reduce the risk of bleb failure. Combined phacotrabeculectomy should be reserved for end-stage glaucoma in most cases, in order to reduce the risk of ‘wipe-out’.

Dynamic Assessment of Binocular Eye Movement Coordination: Norms and Functional Implications

Erik Viirre

Medical hypothesis discovery and innovation in ophthalmology, Vol. 3 No. 1 (2014), 1 March 2014 , Page 31-37

Alignment of the two eyes is controlled by a finely tuned, fast acting system with components within the brain. Assessment of binocular alignment has classically been done statically. Eye positions are assessed in primary position and at eccentric angles to interpret the functional status of the oculomotor nerves and muscles. However, assessment of dynamic eye alignment, the coordination of the eyes during eye movements, has been less commonly carried out and has not been formalized with population norms. Clinicians are aware of slow eye movement dynamic alignment changes, such as that clinically observed in Intranuclear Ophthalmoplegia. But assessment of eye alignment during rapid eye movements, such as saccade or pursuit has not been part of neuro-ophthalmologic assessment. With the advent of inexpensive, high resolution recording systems, both eyes can be simultaneously recorded and their coordination during movement compared. Thus, we now have an opportunity to provide a laboratory based objective measurement of a gamut of binocular coordination systems. Recent research in humans has demonstrated increased variability of binocular coordination during divided attention. Variability is an interesting statistic that can be sensitively assessed in the velocity domain without extensive gaze position recalibration procedures during recording over long intervals. Variability can thus be used as a robust, long-term eye movement parameter with minimal intrusiveness to the subject. It is proposed that population studies of binocular coordination during eye movements be carried out to determine neurologic norms so that conditions such as brain injury and others can be assessed with a functional tool with objective parameters.