Small Pupil--Big Problem: A Management Algorithm

Dilation devices in cataract surgery

PURPOSE OF REVIEW

Cataract surgery in the setting of small pupil represent a major challenge and it is associated with a higher risk of complications. When pharmacologic pupil dilation fails, mechanical pupil expansion devices are needed to obtain and maintain sufficient intraoperative mydriasis. The purpose of this review is to assess the pupil expansion devices currently available.

RECENT FINDINGS

A variety of pupil expansion devices are offered on the market. They differ for design, material, shape, size, cost, and easiness of insertion/removal, nonetheless they all seem to be effective in improving the pupil size and easing the cataract surgery.

SUMMARY

Mechanical pupil expansion can be effectively achieved with a variety of devices, which are well tolerated and can facilitate cataract surgery in the setting of poor mydriasis.

[Surgical treatment of hypermature cataract in patients with lens subluxation and small pupil]

Studying the possibilities of hybrid (femtosecond laser-assisted) phacoemulsification in complicated situations is a relevant problem in cataract surgery.

PURPOSE

To develop a technique for hybrid (femtosecond laser-assisted) phacoemulsification in patients with a combination of hypermature cataract, small pupil and lens subluxation.

MATERIAL AND METHODS

Hybrid (femtosecond laser-assisted) phacoemulsification of hypermature cataracts was performed in 36 patients (36 eyes) aged 63 to 78 years with grade I-II lens subluxation in combination with small pupil. The initial circular femtolaser capsulotomy was performed within the small pupil using the VICTUS system (Technolas Perfect Vision, Germany). After dilating the pupil with retractor hooks, the capsulorhexis was manually expanded to the required diameter.

RESULTS

In all cases, the resulting capsulorhexis had a regular round shape with a smooth edge, without radial ruptures. This made it possible to apply modern methods of fixation and centration of the capsular bag in case of lens subluxation and to perform intracapsular implantation of an intraocular lens (IOL). Complete intracapsular fixation of the IOL with optics edge fully covered by the edge of the capsulorhexis in the postoperative period was achieved in 34 (94.4%) cases. In 2 (5.6%) cases in the postoperative period, the edge of the capsulorhexis exceeded the edge of the IOL optics. The loss of corneal endothelial cells 3 months after surgery was 8.8±1.9%.

CONCLUSION

The use of the proposed combined technique of capsulorhexis made it possible to perform the most physiologically appropriate intracapsular IOL implantation in all patients with hypermature cataract, small pupil and lens subluxation.

Evaluation of a uniplanar pupil expansion ring in small-pupil cataract surgery: a feasibility study

PURPOSE

The aim of this study was to evaluate the effectiveness of a disposable uniplanar pupil expansion device in small-pupil cataract surgery.

METHODS

This is a feasibility study carried out at the Rothschild Foundation, Paris, France. Patients undergoing routine cataract surgery with a dilated pupil size < 6 mm, and who agreed to participate in the study were included. The trial enrolled 25 patients, of whom 21 proceeded to cataract surgery using the pupil expansion device to be evaluated. The pupil diameter was measured at defined stages during the cataract surgery, which was performed by a single surgeon, in a single center setting. The 1st generation Bhattacharjee pupil expansion ring was used if the preoperative pupil size was < 6 mm. Intraoperative and postoperative adverse events were recorded.

RESULTS

Pupil size immediately after the Bhattacharjee ring implantation was ≥ 6 mm for 15 eyes (71.4%). The mean dilated pupil size before ring insertion was 4.5 ± 0.8 mm (range 2.5-5.8 mm), and the mean pupil size after ring insertion was 6.1 ± 0.3 mm (range 5.9-6.8 mm). Mean pupil size following removal of the ring was 4.2 ± 0.8 mm (range 2.5-5.4 mm). Two adverse events occurred during the surgeries: 1 Bhattacharjee ring broke prior to implantation, and 1 implanted Bhattacharjee ring was unstable and removed before the end of the surgery. No postoperative adverse event was recorded.

CONCLUSIONS

The Bhattacharjee ring is an effective pupil expansion device, which facilitates stable pupil expansion during cataract surgery. This study was registered as a clinical trial at clinicaltrials.gov under the number NCT02434588.

The Relationship of the Urotensin-2 Level in the Aqueous Humor with Systemic Diseases and Pupil Size: Comparative Study

Purpose: To detect the presence of urotensin-2 (U-II) in the aqueous humor and evaluate the relationship between aqueous humor level and systemic diseases and pupil size. Methods: The study included 88 patients who underwent cataract surgery. Those with a pupil diameter (PD) of up to 4 mm were considered to have small dilation, those with 4-7 mm of dilatation were considered to have moderate dilation, and those with a PD of more than 7 mm considered to have large dilation. Patients with HT (hypertension) were classified as group 1, those with DM (diabetes mellitus) as group 2, and those with HT+DM as group 3, and those without any systemic disease as group 4. The U-II levels in humor aqueous samples taken from anterior chamber were measured. Results: When compared with the control group, it was observed that the level of U-II in the aqueous humor of the HT, DM, and DM+HT groups was significantly higher (P < 0.05). At the same time, when we compared the DM+HT group with the other groups, the level of U-II in the aqueous humor was significantly higher compared to the group with DM (P < 0.05). The U-II levels of the aqueous humor were higher in the patients with small pupils compared to the remaining groups (P < 0.005). Conclusion: U-II may play a role in small pupil pathophysiology. In addition, it was determined that patients with HT and/or diabetes had higher U-II levels in the aqueous humor than healthy individuals.

Intraoperative difficulties, complications and self-assessed visual function in cataract surgery

PURPOSE

To study associations between intraoperative difficulties and changes in patient-perceived and postoperative visual function and visual satisfaction after cataract surgery.

METHODS

Swedish multicenter, prospective, cross-sectional, nonrandomized, National Cataract Register study. A total of 10 979 patients (n = 10 979) who underwent cataract surgery from 2008 to 2011 completed the Catquest-9SF questionnaire before and 3 months postoperatively. Using Rasch analysis, we converted the nonparametric grading of the answers to parametric data and performed parametric statistical analyses. Multiple regression models were used to examine possible predictors associated with self-assessed visual function after cataract surgery.

RESULTS

Greater improvement in self-assessed visual function was seen in patients in whom trypan blue dye was used; those without a posterior capsular tear or an ocular comorbidity; and those who were younger, female and had low preoperative corrected distance visual acuity (CDVA) or high postoperative CDVA compared with their counterparts. Significantly higher self-assessed postoperative visual function was seen in patients in whom trypan blue dye was used and those with no posterior capsular tear or ocular comorbidity and no use of capsular hooks; and those who were younger and had low preoperative or high postoperative CDVA compared with their counterparts. The risk of general dissatisfaction after cataract surgery was significantly greater in patients with a posterior capsule tear, ocular comorbidity or low postoperative CDVA, and those in whom mechanical pupillary stretching was performed.

CONCLUSION

Several intraoperative difficulties, posterior capsular tear, ocular comorbidity, age, gender, and preoperative and postoperative CDVAs affect patient improvement and self-assessed visual function after cataract surgery.

[Mechanical dilation of the pupil and its possible applications in femtosecond laser-assisted cataract surgery]

In certain cases intraoperative pupil dilation during cataract surgery may be necessary to improve the visualization of intraocular structures and assure the atraumatic nature of surgical manipulations. The article reviews a wide range of pupil expanders, their historical aspects and possibilities of their application in modern cataract surgery.