Injection Of Balanced Salt Solution Research Articles

A randomized clinical trial of combined topical-intracameral anesthesia in cataract surgery

Objective To evaluate the level of patient discomfort during phacoemulsification and implantation of a foldable intraocular lens (IOL) while under topical lidocaine, alone or in combination with intracameral lidocaine. Design A prospective, randomized, controlled trial. Participants Between January and July 1997, a total of 162 patients (162 eyes) scheduled for cataract surgery were randomly assigned to either the placebo group (topical anesthesia with intracameral balanced salt solution [group 1, n = 81]) or the interventional group (combined topical-intracameral anesthesia [group 2, n = 81]). Interventions All patients underwent temporal clear corneal phacoemulsification and implantation of a foldable silicone IOL. All patients received a minimum total of five doses (two drops per dose) of 2% topical lidocaine hydrochloride. Three doses were administered before surgery into the superior and inferior cul-de-sac at 10 minutes, 5 minutes, and immediately before the initial corneal incision. One dose was administered before the commencement of phacoemulsification and another dose before implantation of the IOL. In addition, all patients received an intracameral injection immediately after entrance into the anterior chamber. Patients in group 1 received a 0.5-ml injection of balanced salt solution, and those in group 2 received a 0.5-ml injection of 1% lidocaine. Main outcome measure A 10-point visual analogue scale was used immediately after the surgery to assess each patient’s overall severity of pain intraoperatively. Results Ninety percent of patients in group 1 and 95% in group 2 assigned a score of 0 or 1 to the level of intraoperative discomfort. The mean pain score +/−1 standard deviation for group 1 was 0.63 ± 0.68 and for group 2 was 0.37 ± 0.58. The difference between the pain scores for the two groups was statistically significant ( P = 0.0053). A small but significant proportion (15%) of patients in group 1 expressed distress when the ciliary body was stretched or the iris was manipulated with instruments. Conclusion Although topical lidocaine alone provides adequate anesthesia for phacoemulsification and implantation of a foldable IOL, combined topical and intracameral administration of lidocaine can further minimize intraoperative discomfort.

Initial experience with the HydroSonics instrument to soften cataracts before phacoemulsification

An ultrasonically driven needle placed into the body of the nucleus, with subsequent injection of balanced salt solution (BSS), can be used to fragment the nucleus into sections or lamellae that can potentially be emulsified with greater ease and less ultrasound energy delivered to the eye. This separation of the nucleus has been designated hydrodelineation. The six surgeons participating in this study subjectively reported that the use of hydrodelineation facilitated phacoemulsification, on average, in 91 % of their cases. Review of study data indicated that significantly less ultrasound time and cumulative displayed energy were noted in phacoemulsification of grade 2+ and 3+ cataracts after hydrodelineation than in cases in which hydrodelineation was not performed. The results in cases performed with and without hydrodelineation were statistically equivalent in complications and postoperative patient outcomes.

Posterior Continuous Curvilinear Capsulorhexis: An Experimental Study with Clinical Applications

The posterior continuous curvilinear capsulorhexis technique has been advocated in cases of posterior capsule rupture during extracapsular cataract extraction. The authors compared posterior continuous curvilinear capsulorhexis with posterior capsular sharp-edged tears. Two different types of forces were experimentally created on the posterior capsule of 30 human eyes obtained after death: (1) implantation and dialing of posterior chamber intraocular lenses (PC IOLs) and (2) increased intravitreal pressure by injection of balanced salt solution. All posterior capsular tears extended toward the equator, causing major capsular defects. In contrast, the posterior continuous curvilinear capsulorhexis remained intact in all cases. This experimental study proves that in cases where an inadvertent posterior capsular tear occurs, a posterior continuous curvilinear capsulorhexis is useful in preventing further capsular damage. Also, in cases where a posterior capsulotomy is indicated, a smooth edge created by a posterior continuous curvilinear capsulorhexis may be useful to maintain the integrity of the capsular bag for PC IOL capsular implantation.

Multilamellar hydrodissection in phacoemulsification and planned extracapsular surgery

Multilamellar hydrodissection is the injection of balanced salt solution into multiple lamellae of the lens, cleaving it into a small nucleus and multiple layers of cortex. In phacoemulsification, the smaller nucleus reduces phacoemulsification time, and the thicker bed of cortex provides greater protection for the posterior capsule. In extracapsular extraction, the smaller nucleus can be more readily extracted, which is particularly advantageous when capsulorhexis is performed. Creation of multiple cortical lamellae facilitates their aspiration, either with the phacoemulsification or irrigation/aspiration tips. Multilamellar hydrodissection increases the predictability and safety of phacoemulsification and planned extracapsular cataract extraction.

Replacement of the liquid vitreus with sodium hyaluronate in monkeys: II. Long-term evaluation

Highly purified, large molecular weight fractions of Na-hyaluronate (Healon) dissolved in physiological buffer solution in 1% concentration form viscous pastes. When 1 ml of this paste was implanted into the vitreous space of 82 owl monkey (Aotus trivirgatus) eyes, no pathological changes could be observed months or years (up to 9 years) after implantation. Implantations were made as many as seven times into the same eye without observable pathological changes in the eye. Subcortical lenticular opacities occurred in 4% of all implantations and pigmented chorioretinal lesions occurred in 8% of all implantations. The chorioretinal lesions developed in some cases after injection of balanced salt solution (BSS). This pathology was studied with electronmicroscopy. No correlation could be found between the Na-hyaluronate implantation and the development of these lesions. This pathology is believed to be caused by the surgical trauma during the exchange of half of the total volume of the liquid vitreus with balanced salt solution. During this process a mechanical dislocation between the retinal pigment epithelium and the neuroretina can occur which triggers pigment cell proliferation and subsequent pathological changes. No evidence was found of any immunogenic reaction caused by the implantation of Na-hyaluronate. The increase in vitreous protein resulting from implantation of Na-HA was three times that found after implantation of either BSS or Healon. Neither Healon nor Na-HA caused significant changes in IOP.