Dan D. Gaton

Non-retinovascular leakage in diabetic maculopathy.

BACKGROUND--Diabetic macular oedema is the leading cause of vision deterioration in diabetic retinopathy. Extracellular fluid within the retina, which distorts the retinal architecture, was assumed to be strictly of retinal vasculature origin. However, there is some experimental evidence supporting clinical observations suggesting a possible role of the retinal pigment epithelium (RPE). An unusual form of diabetic maculopathy is presented in which the RPE and the subretinal space play the main role. METHODS--Fluorescein angiograms of 1850 non-proliferative diabetic retinopathy (NPDR) patients were examined. Nineteen eyes (14 patients, 1% of NPDR patients) met the criteria-mainly having minimal diabetic retinopathy with only a few microaneurysms and no clinically significant macular oedema (CSMO). Early phase angiograms were compared with late phase angiograms. RESULTS--It was found that in all 19 eyes the area of diffuse RPE late phase leakage was spread around the macular area. No cystic changes or cystoid macular oedema were present in any of the eyes and the visual acuity was 6/10 or better in all the eyes. CONCLUSIONS--Possible changes occur in the RPE that may be responsible for the late leakage in NPDR patients-namely, diabetic retinal pigment epitheliopathy. These changes are associated with a breakdown of the outer blood-retinal barrier, consisting of leakage through RPE cells. No focal or diffuse leakage across the RPE has been reported in the literature related to the fluorescein angiograms in diffuse diabetic maculopathy.

Toxic Effects of Systemic Retinoids on Meibomian Glands

Systemic use of retinoids is common in the treatment of various dermatological disorders. Blepharitis and conjunctivitis have been reported in 20-45% of the patients following systemic treatment with 13-cis-retinoic acid. Our purpose was to study the histopathological changes in the eyelids caused by long-term systemic treatment of female New Zealand rabbits with isotretinoin (2 mg/kg) and etretinate (2 mg/kg). The histopathological evaluation showed degenerative changes in the meibomian gland acini, leading to cell necrosis and a decrease in the basaloid cells lining the acini walls. No evidence of acute or chronic inflammatory reaction was noted.

Blood-Flow Velocity in Glaucoma Patients Measured with the Retinal Function Imager

ABSTRACT Purpose: Circulatory abnormalities in the retina, optic nerve and choroid have been detected by various technologies in glaucoma patients. However, there is no clear understanding of the role of blood flow in glaucoma. The purpose of this study was to compare retinal blood-flow velocities using the retinal function imager (RFI) between glaucoma and healthy subjects. Materials and Methods: Fifty-nine eyes of 46 patients with primary open-angle glaucoma (POAG), 51 eyes of 31 healthy individuals and 28 eyes of 23 patients with glaucomatous optic neuropathy (GON) but normal perimetry were recruited for this study. Three eyes of 2 patients in the glaucoma group and 2 eyes of 1 patient in the GON group had normal pressure at the time of diagnosis. Eighty-three percent of the glaucoma patients and 73% of the patients in the GON group were treated with anti-glaucoma medications. All patients were scanned by the RFI. Differences among groups were assessed by mixed linear models. Results: The average venous velocity in the GON group (3.8 mm/s) was significantly faster than in the glaucoma (3.3 mm/s, p = 0.03) and healthy (3.0 mm/s, p = 0.005) groups. The arterial velocity in the GON group was not different from any of the other study groups (4.7 mm/s). The arterial and venous velocity in the POAG eyes was not different than in the healthy eyes (arterial: 4.3 versus 4.2 mm/s, p = 0.7; venous: 3.3 versus 3.0 mm/s, p = 0.3). A subgroup of 13 glaucoma patients who had perimetric glaucoma in 1 eye and normal visual field (VF) in the fellow eye showed a trend of lower velocity in the glaucoma eyes. Conclusions: Changes in retinal blood-flow velocity were detected only in the pre-perimetric state, but not in perimetric glaucoma. These findings might represent early dysregulation in the retinal vasculature.

Augmented trabeculectomy in paediatric glaucoma.

Aims: To report the experience with trabeculectomy augmented with mitomycin C and 5-fluorouracil for the treatment of paediatric glaucoma. Methods: Retrospective, interventional case series design was used. The sample included 17 children (29 eyes) with primary (19 eyes) or secondary (10 eyes) glaucoma who were treated with augmented trabeculectomy as the primary procedure between 1990 and 2002. Data were collected on age and family history, preoperative and end of follow up intraocular pressure, cup/disc ratio (evaluated by drawing), visual acuity, complications, and post-surgery treatment. Results: Patient age at surgery ranged from 1 month to 8 years; most patients (n = 14, 82.3%) were aged less than 1 year (range 1 month–8 months, mean 3.95 (SD 2.56) months); three patients (17.7%) were aged 3, 5, and 8 years. The duration of follow up was 3–120 months (mean 46 months). Intraocular pressure significantly improved from 21 mm Hg to 60 mm Hg (mean 33.1 (10) mm Hg) before surgery to 6–26 mm Hg (mean 17.1 (6) mm Hg) after, (p <0.0001). There was no significant change in cup/disc ratio: 0.1–0.8 (mean 0.42 (0.26)) before and 0.1–1.0 (mean 0.511 (0.27)) after (p = 0.45). In 22 eyes (75.8%), intraocular pressure was controlled at less than 20 mm Hg and the cup/disc ratio remained stable or improved. The life table success rate for intraocular pressure control remained stable at 86% at the 12, 24, and 36 months and after 48 months decreased to 53%. There was no significant difference in the life table results between primary and secondary glaucoma. 14 eyes (48.2%) had a visual acuity better than 20/120 by the end of follow up. Repeated surgery was necessary in eight eyes (27.5%), and additional antiglaucoma treatment in 13 (44.8%). Complications included retinal detachment 1 year after surgery, choroidal detachment, and blebitis (one eye each). Conclusions: Augmented trabeculectomy with mitomycin C and 5-fluorouracil may serve as the primary procedure in a selected group of paediatric patients with glaucoma.

Pupillary block following posterior chamber intraocular lens implantation in adults

Background: Pupillary block rarely occurs after cataract extraction with posterior chamber intraocular lens implantation. Methods: A series of six patients (seven eyes) treated for pupillary block after posterior chamber intraocular lens implantation between 1990 and 2001 is described; in one eye, the attack occurred after phacoemulsification. Results: The interval between pupillary block development and the cataract surgery ranged from 1 day to 5 years. In all eyes, treatment consisted of neodymium-YAG laser peripheral iridotomy. In four eyes, the laser peripheral iridotomy relieved the block (one procedure in two; two to three procedures in two). One patient was also treated with YAG capsulotomy, and two patients needed additional surgical intervention. Conclusion: Despite the rarity of the complication of pupillary block after posterior chamber intraocular lens implantation, physicians should be aware of the sometimes difficult course of recovery after treatment.

The combination of topical ceftazidime and aminoglycosides in the treatment of refractory pseudomonal keratitis

Abstract · Background: Pseudomonal keratitis is a serious and potentially blinding infection. · Methods: We treated 12 patients with culture-positive fulminant pseudomonal keratitis with a topical combination of ceftazidime ophthalmic solution (50 mg/ml) and aminoglycosides (14 mg/ml). None of these patients had responded to the standard initial therapy with topical fortified gentamicin or tobramycin (14 mg/ml) combined with cefazolin (50 mg/ml). · Results: Substitution of cefazolin by ceftazidime achieved a remarkable clinical improvement during the first 24–48 h of administration in all cases. The average time of healing after initiation of the combination of ceftazidime and fortified aminoglycosides was 21±15 days. No serious side effects accompanied ceftazidime administration. In vitro susceptibility testing showed resistance to gentamicin or tobramycin in 33% of cases (4/12) and sensitivity to ceftazidime in all cases. · Conclusions: The combination of ceftazidime, in a 5% solution, and fortified aminoglycosides (1.4%) may be a useful, safe and effective topical therapy for the treatment of pseudomonal keratitis resistant to aminoglycosides.

Three-dimensional Measurements of Central Serous Chorioretinopathy Using a Scanning Laser Tomograph

PURPOSE To evaluate the topographic three-dimensional mapping of retinal elevation in central serous chorioretinopathy using the Heidelberg Retina Tomograph and to correlate the measured parameters with the fluorescein angiographic findings. METHODS Seventy-six consecutive patients with central serous chorioretinopathy (63 men, 13 women), between 26 and 54 years of age, were examined to identify areas of neurosensory retinal detachment and fluorescein leakage. In areas of retinal detachment, the parameters measured were the area, volume, maximal height, and diameters of the retinal elevation, which were statistically analyzed, and the correlations between these parameters were evaluated. RESULTS Mean +/- SD area of elevation was 9.6 +/- 5.22 mm2 (range, 2.7 to 21.5 mm2); mean volume was 1.16 +/- 1.3 mm3 (range, 0.11 to 4.73 mm3); mean maximal height was 238 +/- 108 microns (range, 97 to 450 microns); mean x-axis was 3.4 +/- 1.1 mm (range, 1.6 to 5.6 mm); and mean y-axis was 3.03 +/- 0.98 mm (range, 1.6 to 4.7 mm). Most of the retinal elevations were oval (the x-axis longer than the y-axis); the maximal height was in the geometric center in the smaller blebs and below the geometric center in the larger blebs. There were statistically significant correlations between area, volume, and height of the sensory elevation. No correlation was found between the location and the shape of leakage on fluorescein angiography and the Heidelberg Retina Tomograph measurements. CONCLUSIONS Confocal laser tomography is potentially useful as a noninvasive diagnostic technique for quantitative measurements of the neurosensory retinal detachment in central serous chorioretinopathy.

Effects of job-related stress and burnout on asthenopia among high-tech workers

Eye- and vision-related symptoms are the most frequent health problems among computer users. The findings of eye strain, tired eyes, eye irritation, burning sensation, redness, blurred vision and double vision, when appearing together, have recently been termed ‘computer vision syndrome’, or asthenopia. To examine the frequency and intensity of asthenopia among individuals employed in research and development departments of high-tech firms and the effects of job stress and burnout on ocular complaints, this study included 106 subjects, 42 high-tech workers (study group) and 64 bank employees (control group). All participants completed self-report questionnaires covering demographics, asthenopia, satisfaction with work environmental conditions, job-related stress and burnout. There was a significant between-group difference in the intensity of asthenopia, but not in its frequency. Burnout appeared to be a significant contributing factor to the intensity and frequency of asthenopia. This study shows that burnout is a significant factor in asthenopic complaints in high-tech workers. Practitioner Summary:This manuscript analyses the effects of psychological environmental factors, such as job stress and burnout, on ocular complaints at the workplace of computer users. The findings may have an ergonomic impact on how to improve health, safety and comfort of the working environment among computer users, for better perception of the job environment, efficacy and production.

The effect of topical ceftazidime on pseudomonas keratitis in rabbits.

Ceftazidime is a β -lactam antibiotic highly effective against Pseudomonas aeruginosa infection. Using a rabbit model of Pseudomonas keratitis, 103 bacteria (in 20 µ l) were injected unilaterally into the corneal stroma of albino rabbits. Twenty-six hours after inoculation, topical Ceftazidime (50 mg/ml) drops were administered for 48 h, following which the corneal tissue was cultured. Eighteen of 20 corneal cultures (90%) from rabbits treated with Ceftazidime drops were negative. In comparison, all untreated control group cultures showed florid bacterial growth. These results suggest that topical Ceftazidime may be a useful agent in the treatment of P. aeruginosa keratitis.

Mobile Laser Indirect Ophthalmoscope: For the Induction of Choroidal Neovascularization in a Mouse Model

ABSTRACT Purpose: This study aims to evaluate and standardize the reliability of a mobile laser indirect ophthalmoscope in the induction of choroidal neovascularization (CNV) in a mouse model. Materials & Methods: A diode laser indirect ophthalmoscope was used to induce CNV in pigmented male C57BL/6J mice. Standardization of spot size and laser intensity was determined using different aspheric lenses with increasing laser intensities applied around the optic disc. Development of CNV was evaluated 1, 5, and 14 days post laser application using fluorescein angiography (FA), histology, and choroidal flat mounts stained for the endothelial marker CD31 and FITC-dextran. Correlation between the number of laser hits to the number and size of developed CNV lesions was determined using flat mount choroid staining. The ability of intravitreally injected anti-human and anti-mouse VEGF antibodies to inhibit CNV induced by the mobile laser was evaluated. Results: Laser parameters were standardized on 350 mW for 100 msec, using the 90 diopter lens to accomplish the highest incidence of Bruch’s membrane rupture. CNV lesions’ formation was validated on days 5 and 14 post laser injury, though FA showed leakage on as early as day 1. The number of laser hits was significantly correlated with the CNV area. CNV growth was successfully inhibited by both anti-human and mouse VEGF antibodies. Conclusion: The mobile laser indirect ophthalmoscope can serve as a feasible and a reliable alternative method for the CNV induction in a mouse model.