Safety of Trypan Blue Capsule Staining to Corneal Endothelium in Patients with Diabetic Retinopathy

The effect of adrenaline and trypan blue used during cataract surgery on anatomical and functional outcomes in pseudoexfoliation syndrome patients

PURPOSE

To evaluate the effect of the intracameral adrenaline and trypan blue used during cataract surgery on corneal endothelial parameters in pseudoexfoliation syndrome (PEX) patients.

METHODS

The patients were divided into four groups according to intraoperative use of agents during cataract surgery: intracameral adrenaline (1/10,000, 0.1 ml) (group 1), trypan blue (0.6 mg/ml, 0.1 ml) (group 2), combination of adrenaline and trypan blue (group 3) and none (group 4).

RESULTS

Preoperative ECD, CV, HEX and CCT parameters were similar between the groups. A mean loss of 12.7% in ECD was observed at the postoperative third months compared to the preoperative. In group 3, ECD was found to be lower in the postoperative third months compared to the preoperative (p = 0.014). In the other groups, no statistically significant difference was found in preoperative and postoperative comparisons.

CONCLUSION

In conclusion, the utilization of intracameral adrenaline or trypan blue did not cause a significant difference in corneal endothelium in PEX patients. However, their combined use may have a negative effect on endothelial cell density. In a cataract surgery performed in the presence of PEX, the increased likelihood of endothelial damage should be taken into consideration, and appropriate precautions should be taken preoperatively and intraoperatively.

Corneal endothelial protection during manual small-incision cataract surgery: A narrative review

Cataract causes bilateral blindness in 20 million people globally, the vast majority of whom live in developing countries. Manual small-incision cataract surgery (MSICS) has emerged as an efficient and economical alternative to phacoemulsification, giving comparable results in terms of final visual gain. One of the important determinants of postoperative visual gain is the status of the corneal endothelium. Multiple factors such as corneal distortion, irrigation solution turbulence, mechanical trauma by instruments, nuclear fragments, intraocular lens contact, and free oxygen radicals, all have been implicated in causing corneal damage during cataract surgery. MSICS with posterior chamber intraocular lens implantation has been reported to cause an endothelial cell loss of 15.83%, which is comparable with other modes of cataract surgery like extracapsular cataract extraction and phacoemulsification. Thorough preoperative assessment of endothelial status and taking necessary steps for endothelial protection during surgery can decrease the endothelial cell loss and overall burden of pseudophakic bullous keratopathy. In addition to surgical techniques, the type of irrigating solutions, ocular viscoelastic devices, intracameral dyes, and drugs all affect the endothelial cell status. This review presents a summary of available literature on the protection of endothelial cells during different steps of MSICS. This is especially relevant for developing countries where large-scale MSICS cataract surgeries are performed to decrease the cataract blindness burden.

Corneal endothelial cell density loss following glaucoma surgery alone or in combination with cataract surgery: A systematic review and meta-analysis

TOPIC

Corneal endothelial cell density (ECD) loss following glaucoma surgery with or without cataract surgery.

CLINICAL RELEVANCE

Corneal ECD loss may occur due to intraoperative surgical trauma in glaucoma surgery or postoperatively with chronic endothelial cell trauma or irritation.

METHODS

Trabeculectomy, glaucoma filtration surgery or microinvasive glaucoma surgery in participants with ocular hypertension, primary and secondary open angle glaucoma, normal tension glaucoma and angle-closure glaucoma were included. Pediatric populations and participants with pre-existing corneal disease were excluded. Laser treatments and peripheral iridotomy were excluded. Electronic databases searched in December 2021 included MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov and The International Prospective Register of Systematic Reviews (PROSPERO), FDA PMA and FDA 510(k).

RESULTS

39 studies were included in quantitative synthesis. 12 months following suprachoroidal MIGS mean ECD loss was 282 cells/mm² (95% Confidence Interval (CI) 220 to 345; p <0.00001; Chi² = 0.06; I² = 0%; 2 studies; very low certainty). Mean ECD loss after Schlemm's canal implantable devices was 338 cells/mm² (95% CI 185 to 491; p<0.0001; Chi² = 0.08; I² = 0%; 2 studies; low certainty) at 12 months. When compared to phacoemulsification alone, Schlemm's canal implants combined with phacoemulsification showed statistically significant mean ECD reduction at 24 months; mean difference of ECD was -19% (95% CI -37% to -2%; p=0.03; Chi² = 3.04; I² = 34%; 3 studies; low certainty). Mean ECD loss was 64 cells/mm² (95% CI 21 to 107; p=0.004; Chi² = 4.55; I² = 0%; 6 studies; low certainty) following Schlemm's canal procedures (without implantable devices) at 12 months. At 12 months the mean ECD loss after trabeculectomy was 33 cells/mm² (95% CI -38 to 105, p=0.36, Chi² = 1.17; I² = 0%; moderate certainty). At 12 months mean ECD loss was 121 cells/mm² (95% CI 53 to 189; p=0.0005; Chi² = 3.00; I² = 0%; 5 studies; low certainty) after Express implantation. When compared to control fellow eye, aqueous shunt surgery reduced ECD by 5.75% (95% CI -0.93 to 12.43; p=0.09 Chi² = 1.32; I² = 0%; low certainty) and 8.11% ECD loss (95%CI 0.06 to 16.16 p=0.05; Chi²= 1.93; I²=48%) at 12 and 24 months, respectively.

CONCLUSIONS

Overall there is low certainty evidence to suggest that glaucoma surgery involving long-term implants has a greater extent of ECD loss than glaucoma filtration surgeries without the use of implants. The results of this review support long-term follow-up (beyond 36 months) to assess ECD loss and corneal decompensation following implantation of glaucoma drainage implants.

Ex-Vivo Method to Quantifiably Evaluate the Staining Effectiveness of Anterior Lens Capsule Dyes

Purpose

High frequency of cataracts and the requirements of new European Union regulations for medical devices require the availability of preclinical models to adequately evaluate anterior lens capsule dyes before their use in patients. Herein, we describe an ex vivo method to quantifiably evaluate the macroscopic and microscopic staining effectiveness of anterior lens capsule dyes using porcine eyes.

Methods

Commercially available trypan blue–based products or physiological saline solution (negative control) was injected into porcine eyes. Anterior pole and lens (after extraction) were macroscopically photographed, and the images were quantitatively analyzed. Lenses were histologically processed, and the staining intensity microscopically was semiquantified.

Results

Macroscopic evaluation of the anterior pole revealed bluish staining of the anterior capsule; however, this coloring cannot be macroscopically discerned after lens extraction. Quantitative image analyses showed significant (P < 0.01) staining of the lens capsule compared to the negative control, but not significant (P > 0.05) between the products tested. Quantitative analysis of dying on lens images could not be performed. Microscopic semiquantification of the capsule staining intensity allows us to appreciate differences between products.

Conclusions

The described method is a quick and useful tool for macroscopic evaluation by surgeons to choose an anterior capsule staining for use during everyday surgeries, and a more specific microscopic evaluation also allows us to determine the effectiveness and usefulness of these products.

Translational Relevance

This method satisfies preclinical effectiveness evaluations required by European Union regulations and complements the safety and toxicity evaluations that new products must guarantee before they enter the market and are used in clinical practice.

The effects of trypan blue use on the corneal endothelium during cataract surgery in patients with pseudoexfoliation syndrome (PEX)

PURPOSE

In the present clinical study, it was aimed to investigate the possible effects of Trypan blue (TB) use on the corneal endothelium during cataract surgery in eyes with pseudoexfoliation syndrome (PEX) during a three-month follow-up period using the contralateral eye control design.

METHODS

This prospective, randomised controlled, individual cohort study included 92 eyes of 46 patients with bilateral PEX and cataracts. While 1% TB was applied to one eye of the patients before capsulorhexis (study group), it was not applied to the other eye (control group). Both groups were compared preoperatively and postoperatively in terms of endothelial cell density (ECD), endothelial cell loss (%), pleomorphism, polymegathism and central corneal thickness (CCT) using specular microscopy.

RESULTS

Preoperative corneal ECD was measured as 2362.56 ± 253.27 in the study group, 2380.84 ± 220.54 in the control group, and 2145.58 ± 221.71 in the study group and 2184.97 ± 200.94 cells/mm² in the control group in the postoperative 3rd-month follow-up (p = 0.71 and = 0.37, respectively). In addition, there were no significant differences between the two groups in terms of the percentage of hexagonal cells, coefficient of variation (CV), and CCT both preoperatively and postoperatively 3 months later (p = 0.78, =0.39, =0.95 preoperatively and p = 0.31, =0.26, =0.83 postoperatively, respectively).

CONCLUSION

This study demonstrated that the injection of 1% TB into the anterior chamber for staining the anterior capsule during cataract surgery did not cause significant corneal endothelial changes at postoperative 3^rd months, despite the increased fragility of corneal endothelial cells in patients with PEX.