Retina and Vitreous

The rate of lens dislocation into the posterior chamber during phacoemulsification has been reported to be 0.8%. In a 1991 study of Medicare patients, the risk for retinal detachment (RD) after phacoemulsification was reported to be 1.17% in those 65 and older. When an anterior vitrectomy was performed, the RD rate increased to 5%.

This paper documents the course of 121 patients who underwent pars plana vitrectomy (PPV) for retained lens material at Wills Eye Hospital. The PPV technique is believed to be the safest and most effective method for this task. The series reveals the following results:

1. Statistically similar visual acuities were reached regardless if vitrectomy was performed within one week of surgery or not. The timing of vitrectomy surgery for retained lens fragments may not be as important as previously thought.

2. The use of perflourocarbons (18 patients - 15%) during surgery did not statistically effect the RD rate or final visual outcome.

3. The placement of an intraocular lens into the anterior or posterior chamber, whether during the original surgery or subsequently did not statistically affect the final visual acuity.

4. The risk for RD after vitrectomy in general is between 4% and 6%. The rate of RD found in this study was 18% (19 eyes). Visual Acuity was 20/200 or less in 68% of these patients. The cumulative rate of RD post PPV for retained lens fragments in the literature is 17%, with half occurring prior to vitrectomy. Dislocation of nuclear material into the vitreous during phacoemulsification increases the risk for RD which subsequently increases the risk for a poor visual outcome.

Most eyes do well after PPV for retained nuclear fragments. Visual acuity was 20/40 or better in 68% of patients in this study. Of all the complications which can result after losing nuclear material into the vitreous, RD is the most important factor with respect to visual outcome. The authors recommend first looking for a retinal tear or detachment. If none is present, they suggest one can wait until other symptoms (eg. persistent pressure elevation, corneal edema or marked decreased visual acuity) occur before proceeding to vitrectomy.

Retina and Vitreous

Background:

The prognosis of retinal vein occlusion is highly unpredictable because nonischemic types may convert into ischemic types within the first months. This study was designed to identify epidemiologic characteristics of the different types of retinal vein occlusion, their visual outcome, and their prognostic factors.

Methods:

The authors analyzed prospectively the data from patients who have had retinal vein occlusion with complete medical and biologic examination, including fluorescein angiography, and a 1-year follow-up.

Results:

One hundred seventy-five retinal vein occlusion eyes consisted of 120 central retinal vein occlusions (CRVO), 7 hemicentral occlusions, and 48 branch occlusions. In initially nonischemic CRVO eyes, retinal ischemia developed in 54%. The study of prognostic factors in the CRVO group showed that older age, male sex, and the number of risk factors (systemic vascular risk factors and glaucoma) were correlated with a poor visual outcome and with the development of retinal ischemia, as well as baseline visual acuity, initial extent of retinal ischemia, and theologic findings (hematocrit, fibrinogen, and erythrocyte aggregation levels). Logistic regression underlined the prognostic role of sex, the number of risk factors, erythrocyte aggregation, and initial clinical features. Persistent macular edema was shown to be associated with hyperlipidemia and cardiovascular history, and inversely correlated to glaucoma.

Conclusion:

Because clinical characteristics of CRVO may worsen, the authors' results provide a basis to predict visual outcome by taking into account epidemiologic and theologic findings. A careful follow-up of these patients is recommended.

Authors' abstract, Oph
Univ of Paris, France

Retina and Vitreous

In this retrospective study, NEI records from 1984-1994 were reviewed. 25 patients were identified with the diagnosis of primary retinal vasculitis. The mean follow-up time was 4.4 years with four patients being lost to follow-up. The mean visual acuity was 20/100 (20/20 to NLP). On the initial exam, one patient had a Review of Systems suggestive of systemic disease and a subsequent positive ANA DS DNA positive result. This patient was eventually diagnosed with Systemic Lupus Erythematosus (SLE). Of the remaining twenty patients, 5 (20.8%) had false-positive laboratory tests. None of these went on to develop a systemic disease. One patient died of unknown cause.

The authors suggest the work of a patient with primary retinal vasculitis be focused. If a complete history, Review of Systems and eye exam is negative, they suggest the following be performed:

IVF (fluorescein angiogram), complete blood count, sed rate, urinalysis, RPR, FTA-ABS/HATTS, chest X-ray and an HIV test.

If the Review of Systems suggests a collagen vascular disease, extended ANA testing should be performed.

Raymond G. Magauran, M.D.
Buffalo, New York

Retina and Vitreous

Brief Summary:

Discussion:

Time and space constraints prevent me from outlining all of the problems associated with this study and its flawed (or at least not substantiated conclusions).

Firstly, it must be noted that this was not truly randomized as the worst patients on presentation were not enrolled and underwent surgery if the surgeons' clinical judgement was that immediate vitrectomy was required, if a fungal endophthalmitis was suspected, if the patient had a previous injection of antibiotic by a referring physician, or if the patient had a choroidal detachment. Moreover, if the TAP patient did not do well after 36 hours then the surgeon could perform a VIT. This effectively presents a selection bias with the worst patients in the VIT group and the best prognosis patients in the TAP group. Also, the TAP group was itself heterogenous as the "TAP" was also obtained by pars plana VIT instrumentation.

Secondly, only amikacin and vancomycin were used intraocularly (and not ceftazidime and vancomycin as has become standard in many major centers in the last 2 years). Ceftazidime was only used subconjuctivally.

Thirdly, the intravenous medications were only ceftazidime and amikacin (both of which do not cover Gram positive organisms, the most common encountered). This would imply that for Gram positive endophthalmitis, no difference SHOULD be seen between IV and "no IV" treatment groups. A more appropriate combination would have been vancomycin and ceftazidime.

Fourthly, although the final visions were the same between these (unequal) groups, the media clarity was superior in the VIT group--of obvious benefit in one-eyed patients.

Fifth, as 75-80% of the organisms found were Gram positive (and usually coagulase negative) cocci it is perfectly predictable that there would be no difference in the outcomes vis a vis sterilization. (How about more detail on the outcomes in the infections with other organisms?).

Sixth, they conclude that TAP/VIT and antibiotic injection alone (without IV antibiotics) is more cost effective and will reduce the hospital stays--the data do not address this conclusion at all! In fact, this issue is not addressed at all in their data and to make this kind of conclusion only gives unsubstantiated and possibly erroneous ammunition to managed care plans interested in kicking grandma out of the expensive hospital beds.

Points that I found favorable included:

1. The finding that creatinine levels did not rise any more in the IV treated vs non-IV treated patients.
2. They proved that the media cleared more quickly after VIT.
3. They demonstrated a halving of the risk of severe visual loss between these unequal groups (despite the built in bias against the VIT patients).
4. They acknowledge that their conclusions re: IV meds apply ONLY to the drugs that they used and they acknowledge the possible role of IV antibiotics in other forms of endophthalmitis (such as after filtration surgery, in chronic endopthalmitis, or after penetrating intraocular trauma).

Ranjit (Randy) Dhaliwal, MD, FRCSC
Augusta, GA

Retina and Vitreous

The vitreomacular relationships in 44 patients, with 47 eyes with macular holes. Both the involved and fellow eye were examined using static and kinetic techniques.

One presented with 20/200 vision in an eye with a central foveal elevation. A vitreomacular attachment was removed, vision was 20/30 at six months post-op. In another, vision was 20/100 in the affected eye, by visualization vitreous appeared clear, b-scan exam revealed insertion of a vitreous fiber to the macula. There was no surgery, the hole doubled in size over 9 months.

In 30 of 35 eyes with macular hole, attachment of the vitreous to macula was shown with b-scan. There was 94% correlation of findings by echography and biomicroscopic exam: In three eyes, echography revealed PVD not visualized, and other evidence supported echography.

In 60% (24 eyes) , the fellow eye had echographic evidence for vitreomacular attachment, and in 9 of these, there was fiber insertion to the macula.

This provided further support for the cortical vitreous traction theory of macular holes. It provides support for the use of ultrasound examination each eye of the patient who presents with macular hole.

Tom M, Maida
Gainesville, FL

Retina and Vitreous

For the purposes of discussion, I will eliminate the patient with iris capture. That patient's improvement (from 20/80 to 20/70) was not remarkable, and for purposes of this discussion, it does not seem logical to put this isolated patient into a larger category with the other 23 patients.

The inclusion criteria for this study would eliminate most of the patients normally seen with CME and vitreous adhesion anteriorly. The 23 patients in this study were all unresponsive to topical therapy. Additionally, patients were eliminated with visually significant diabetic retinopathy, uveitis, epiretinal membrane, retained crystalline lens fragments, or other significant retinal disease. It is interesting that none of the patients were treated with systemic corticosteroids and that three of the patients never received any type of steroid. Nd:YAG vitreolysis was attempted (unsuccessfully) in one patient. The length of time from the initial cataract surgery did not influence the visual outcome. The data suggested that the location of lens (anterior versus posterior chamber) influenced visual outcome, but the greater improvement with anterior chamber lenses did not reach statistical significance. The authors conclude that vitrectomy is useful in patients with CME and vitreous adherent to anterior structures who have failed to improve with medical treatment.

Keith D. Fisher, M.D.
Texas

Retina and Vitreous

An initial success rate of about 70% is my standard quote given to patients selected using the old criteria for pneumatic. This is compared to an 85 to 90% success rate for buckle. The authors got a 69.2% success rate on the first pneumatic and were able to raise that rate to 71% by doing a second pneumatic on 2 eyes. Using classical criteria their success rate was 75.3%. Follow-up ranged from 1 to 44 months (since the study ended in '92 it would have been nice to have had at least 6 months f/u on everyone).

The data on complications and failures should be studied closely, but is beyond the scope of my 200 words. Notably, macular hole was seen in one patient and subretinal gas was seen in two (both of whom had successful reattachment). Failures were seen more commonly in males, preop vision worse than 20/50, eyes with four quadrants of detachment, and eyes with "additional pathology." Failures are usually due to breaks that are new, missed, reopened, or never closed. The authors make the point that preop patient selection and careful examination is key for maximizing success. This is an excellent article and should be studied closely by anyone considering performing pneumatics. Economic factors will force this procedure on patients and physicians regardless of whether we like this procedure or not.

Keith D. Fisher, M.D.
Southeast Retina Assoc, Texas

Retina and Vitreous

Arch Ophthalmol 113: 456-462, 1995, Apr

A non-ischemic CRVO may progress to an ischemic CRVO. The authors attempt to alter the progression rate by performing high power, focally intense argon laser treatments to the retinal vasculature to create a retinal venous to choroidal venous anastomosis. Fistual formation was documented by flourescein angiogram during weeks 3 to 7 post laser. Successful anastomoses were made in 33% (8 of 24 eyes). Of these, none progressed to the ischemic form. Of the 16 eyes in which the laser treatment did not create a patent venous connection, 31% (5) progressed to ischemic CRVOs with vision ranging from 6/9 to light perception. There were however a variety of complications which need to be closely addressed in the sure to follow prospective, randomize, multi-centered trial.

The natural progression of CRVO from non-ischemic to ischemic forms is thought to be 20%. In this study, the rate, irregardless of laser treatment, was 31%. Does this form of laser increase the risk for developement of ischemic CRVO?

Raymond G. Magauran III, MD
Buffalo, NY

Raymond G. Magauran III, MD
Buffalo, NY

Retina and Vitreous

The authors investigate the efficacy of pars plans vitrectomy and the use of autologous serum in the repair of Stage 3 and 4 macular holes. 9 patients, 11 eyes were enrolled. Ages ranged from 53-80 years old. Follow-up time was 4 to 11 months, mean 4.8 months. Preop vision was 20/80 to 20/200 with a mean of 20/200. All patients underwent the following: Pars plana vitrectomy (PPV), air-fluid exchange, drainage of subretinal fluid (SRF) from the hole, epiretinal membrane peel (if indicated) and proper head positioning for two weeks. There were no control eyes. They report 100% flattening of the macular hole and decreased SRF. All eyes recovered two lines of vision or more. 3 eyes (27%) achieved and maintained 20/40 or better, 7 (64%) were 20/60 or better. No "excessive fibrous proliferation" was noted. Previous reports show PPV alone successfully closes stage 3 and 4 macular holes in 47% of eyes. With the addition of the expensive TGF-Beta, anatomic success rates increase to 85%. The increased success of autologous serum over PPV alone may make this an efficacious and cost effective way to repair macular holes. We look forward to long term controlled studies to investigate this further. In particular, the success rate at two years or longer needs to be examined. A significant portion of previously repaired holes will break down again and result in recurrent visual loss.

Raymond G. Magauran III, MD
Buffalo, NY