Intraocular gas injection in the pseudophakic patient

Effect of air bubble on inflammation after cataract surgery in rabbit eyes

Purpose:

Intense inflammation after cataract surgery can cause cystoid macular edema, posterior synechia and posterior capsule opacification. This experimental study was performed to investigate the effect of air bubble on inflammation when given to anterior chamber of rabbit eyes after cataract surgery.

Materials and Methods:

30 eyes of 15 rabbits were enrolled in the study. One of the two eyes was in the study group and the other eye was in the control group. After surgery air bubble was given to the anterior chamber of the study group eye and balanced salt solution (BSS; Alcon) was left in the anterior chamber of control eye.

Results:

On the first, second, fourth and fifth days, anterior chamber inflammations of the eyes were examined by biomicroscopy. On the sixth day anterior chamber fluid samples were taken for evaluation of nitric oxide levels as an inflammation marker. When the two groups were compared, in the air bubble group there was statistically less inflammation was seen. (1, 2, 4. days P = 0,001, and 5. day P = 0,009).

Conclusions:

These results have shown that when air bubble is left in anterior chamber of rabbits’ eyes after cataract surgery, it reduced inflammation. We believe that, air bubble in the anterior chamber may be more beneficial in the cataract surgery of especially pediatric age group, uveitis patients and diabetics where we see higher inflammation. However, greater and long termed experimental and clinical studies are necessary for more accurate findings.

The effect of C₃F₈ gas on corneal endothelial cells in rabbits

PURPOSE

To evaluate the ocular effects of perfluoropropane gas (C(3)F(8)) in the anterior chamber of rabbit eyes in relation to the gas concentration.

METHODS

Twenty rabbit eyes were randomly divided into four groups (20%, 15%, and 10% C(3)F(8) gas groups, and an air control group). After injection of 0.3 ml of each gas concentration into the anterior chamber, endothelial damage was evaluated by specular microscopic analysis. The main outcome measurements were endothelial cell density, hexagonality, coefficient of variation, corneal thickness, and intraocular pressure (IOP) 1 day, 1 week, and 2 weeks after injection. Two weeks after injection, transmission electronic microscopy was performed to evaluate the structural integrity.

RESULTS

The 20% group had a significant decrease in endothelial cell density (P = 0.023), hexagonality (P = 0.031), and increase in corneal thickness (P = 0.045) from baseline to 2 weeks after injection, whereas the other groups exhibited no significant differences. The 20% group had a significant increase in IOP 1 week after injection (P = 0.041). Transmission electron microscopy revealed that the 20% group had a severe flat cell configuration with a damaged intracellular organization.

CONCLUSIONS

The risk of endothelial cell damage and elevation in IOP was greater in the 20% C(3)F(8) group than in the 15% or 10% C(3)F(8) groups. Therefore, an appropriate concentration of C(3)F(8) gas is needed for different surgical purposes.

Sulphur hexafluoride in the treatment of flat anterior chamber following trabeculectomy

The efficacy and side effects of sulphur hexafluoride (SF6) in the reformation of the flat anterior chamber (AC) after standard trabeculectomies were studied. Ten patients with lenticulocorneal touch following trabeculectomy were enrolled. All had water-tight conjunctival wounds with overflowing fistulas. In 5, one to four surgical attempts to reform the AC were unsuccessful. Two to seven days after trabeculectomy, the AC was reformed by a single injection of SF6/air mixture (20-40%). Gas was injected through the limbus at 3 or 9 o'clock. The AC remained deep after absorption of the gas in 2-7 days. All patients had stromal oedema in the first 4 days. This resolved and specular microscopy did not show any abnormality. After a mean follow-up of 2.5 years, all had normal intraocular pressure, 3 with one topical antiglaucoma treatment. Three patients developed cataracts before and 3 after reformation of the AC. The latter 3 were not anterior capsular cataracts as induced by gases. SF6/air mixture (20-40%) is inert and kind to the cornea and, as it is absorbed in less than 7 days, it exerts minimal damage to the crystalline lens. It is effective in the reformation of flat ACs.