Retina and Vitreous

PURPOSE:
The purpose of the study is to evaluate the effect of vitrectomy on secondary glaucoma and visual acuity outcomes in patients with retained lens fragments after phacoemulsification.

METHODS:
A retrospective analysis of 126 patients who had vitrectomy for retained lens fragments after phacoemulsification during the 3-year period between January 1, 1993, and December 31, 1995.

RESULTS:
Glaucoma, defined as an intraocular pressure of greater than or equal to 30 mmHg, occurred in 42 (36.8%) of 114 patients before vitrectomy and in 4 patients (3.2%) of 126 after vitrectomy. There were no differences in the rates of persistent glaucoma regardless of the intervals between cataract surgery and the vitrectomy: less than or equal to 1 week, 2 patients (4.1%); greater than 1 week to less than or equal to 4 weeks, 1 patient (2.5%) and greater than 4 weeks, 1 patient (2.6%). The visual acuity was 20/40 or better in 13 patients (11.4%) before vitrectomy and in 75 patients (59.5%) after vitrectomy. The rates of visual acuity 20/40 or better also were similar for all intervals: less than or equal to 1 week, 29 patients (59.2%); greater than 1 week to less than or equal to 4 weeks, 22 patients (56.4%) and greater than 4 weeks, 24 patients (63.1%).

CONCLUSIONS:
Vitrectomy for removal of retained lens fragments reduces secondary glaucoma and yields favorable visual acuity outcomes. In eyes with elevated intraocular pressure, early vitrectomy generally is recommended, but delayed vitrectomy also has favorable outcomes.

Authors' abstract, Ophthalmol
Bascom Palmer Eye Institute,
Miami, FL

Retina and Vitreous

PATIENT'S CORNER
Interferon alfa-2a has been shown to be antiangiogenic in animal and in vitro models. The authors attempt to look at its effect in modulating the devastating outcomes typically associated with "wet macular degeneration" hemorrhages in the central portion of vision.

CLINICIAN'S CORNER
Interferon alfa-2a has been used with positive effects in other conditions where angiogenesis of vascular structures is unwanted such as life threatening hemangiomas in the neonatal population and in AIDS patients with Kaposi's sarcomas. The authors completed a prospective randomized placebo-controlled clinical trial.

METHODS: Subfoveal SRN in one eye with AMD changes in the fellow eye. Affect eye's acuity had to be better than 20/320 within 14 days before treatment. Patients excluded included those with more than 12 MPS disc areas of CNV by fluorescein angiography, concurrent eye disease potentially affecting acuity. Additional exclusion criteria are extensive. Please read the article for the long list of excluded conditions. For the most part these patients were very healthy with no or few comorbid conditions.
Follow up period: 12 months
Patients were randomized into four groups: placebo, interferon alfa-2a at 1.5, 3 and 6 million units three times per week for one year. All four groups received matching vials. Blinded reviewers read serial angiograms.

RESULTS: 481 patients were enrolled in 45 centers over a 9 month period.
99% were white, 61% female, 50-89 years old.
18.8% were unavailable for the 52 week follow-up exam.
25 were withdrawn because their angiograms excluded them from inclusion.

DISCUSSION: The statistics are inconclusive regarding the effect on vision. The 6-MIU group had 66 severe or life threatening events occur during treatment compared to 33 in the control group, 34 in the 1.5-MIU group, and 42 in the 3-MIU group. Apparently, angiogenesis is a very important natural process required for life irrespective of the eye.

Raymond Magauran, MD
Boston, MA

Retina and Vitreous

PURPOSE: To evaluate the efficiency, cell specificity, stability, and toxicity of recombinant adeno-associated virus (rAAV)-mediated retinal transduction in vivo in the adult immunocompetent mouse. To assess the usefulness of green fluorescent protein (GFP) for real-time, noninvasive monitoring of retinal transgene expression in vivo.

METHODS: Assessment of ocular GFP expression was performed in cohorts of mice for 11 weeks after subretinal injection of a recombinant adeno-associated virus carrying the complementary DNA (cDNA) for GFP. Examinations were performed in vivo by direct observation of fluorescence by ophthalmoscopy, using excitation-barrier filters. Histologic analyses of retinal tissue were used to identify transduced cells and to assess inflammation.

RESULTS: Retinal GFP expression can be monitored in vivo using real-time, noninvasive imaging. Recombinant AAV efficiently transduces a variety of cells of the neural retina and of the retinal pigment epithelium (RPE). Transgene expression was not observed until 1 week after infection. The number of GFP-expressing cells increased over 3 weeks, and expressing photoreceptors and RPE, cells persisted at least through 11 weeks (the termination of the experiment). There was no clinical or histologic evidence of inflammatory response.

CONCLUSIONS: Retinal gene transfer mediated by rAAV is stable and efficient and is associated with no clinically or histologically detectable toxicity or immune reaction. Green fluorescent protein allows noninvasive assessment of the extent and location of retinal transgene expression as a function of time and promises to be useful alone and as a tag for other transgenes delivered experimentally or therapeutically to the retina

Authors' abstract, IOVS
Scheie Eye Institute,
Philadelphia, PA

Retina and Vitreous

PURPOSE: To evaluate the ophthalmic phenotype in families with three or more individuals who have age-related maculopathy.

METHODS:

Eight families were identified at academic centers in Massachusetts and North Carolina. Macular findings were graded based on a modification of the grading system used in the Age-Related Eye Disease Study (AREDS).

RESULTS:

All families had at least three members with stage 3 (extensive drusen change) or higher maculopathy in at least one eye, and six families had at least two members with advanced maculopathy (stage 4, geographic atrophy of the retinal pigment epithelium, or stage 5, exudative maculopathy). Both stages 4 and 5 maculopathy were observed among different individuals in four families. Individuals with stage 3 maculopathy were members of families with more advanced maculopathy (six families) and were of similar age as more severely affected family members but tended to be older than those with stage 2.

CONCLUSION:

The phenotypic appearance of the macula in families with multiple affected individuals is heterogeneous and representative of the spectrum of macular findings typically associated with age-related maculopathy.

Authors' abstract, AJO
Department of Ophthalmology,
Duke University Medical Center,
Durham, North Carolina

Retina and Vitreous

The blood-ocular barrier (BOB) shares similar neuroepithelial origin, microanatomy and functions with the blood-brain barrier. There are many natural (e. g. diabetes, hypertension) or iatrogenic (chemotherapy, retinal photocoagulation) conditions which can cause a BOB breakdown, resulting in visual acuity impairment or loss. The authors examined 42 patients affected by BOB damage in different pathological conditions. All patients previously underwent a conventional fluoroangiographic (FA) study. Nine patients with normal FA exam were evaluated also. Despite normal MRI findings immediately after Gd-DTPA injection, contrast leakage into the vitreous body or into the aqueous fluid was demonstrated in delayed scans (40-50 min after contrast administration), proving the existence of a BOB damage (sensitively 94 %). Although FA exam remains the choice modality in BOB breakdown demonstration, we propose MRI as a useful diagnostic tool when optic media opacity (cataract, haemovitreous, intraocular silicon oil) occurs, preventing direct retinal fundus imaging and/or an early screening tool.

Authors' abstract, ER
Palermo, Italy

Retina and Vitreous

Not every article written should be published. In its current form, this paper is one of those.

It is a retrospective study which seeks to compare the preoperative and postoperative visual acuities of patients who have undergone surgical removal of a subfoveal neovascular membrane secondary to POHS. Using visual acuity as the measuring stick requires refraction. Only 85% of the patients underwent preop refraction. To make matters worse, only 79% had a postoperative manifest refraction. This means the data is 15% inaccurate at best and may possibly be as inaccurate as 36%.

All is not lost however. We can glean several points of knowledge from this paper.

1. A prospective trial "The Submacular Surgery Trial" is underway where patients are refracted and randomized in a controlled fashion with a standarized data collection for their patients.
2. Surgical complications (14% of eyes) negatively influenced visual outcome immediately postop.
3. Surgery may indeed improve upon the natural history of this disease.

We are anxiously awaiting the prospective trial.

Raymond Magauran, M.D.
St. Joseph's Hospital,
Ann Arbor, Michigan