In vivo analysis of wound architecture in 700 μm microphakonit cataract surgery

Safety and efficacy of gas-forced infusion (air pump) in coaxial phacoemulsification

PURPOSE

To evaluate the safety and efficacy of gas-forced infusion (air pump) in uncomplicated coaxial phacoemulsification.

SETTING

Dr. Agarwal's Eye Hospital, Chennai, India.

DESIGN

Comparative case series.

METHODS

Specular microscopy and optical coherence tomography were used to analyze the endothelium, central macular thickness (CMT), and peripapillary retinal nerve fiber layer (RNFL) thickness before and approximately 1, 7, 30, and 90 days after coaxial phacoemulsification with (infusion group) or without (control group) gas-forced infusion. Surgical time, surge, phaco energy, irrigation fluid volume, surgical ease, complications, and visual gain in the 2 groups were compared.

RESULTS

The mean endothelial cell loss was lower in the infusion group than in the control group (6.98% ± 8.46% [SD] versus 10.54% ± 11.24%; P = .045) and the irrigation/aspiration time significantly shorter (54 ± 39 seconds versus 105 ± 84 seconds; P = .0001). The surgery was rated as easier with gas-forced infusion (scale 1 to 10: mean 8.3 ± 2.1 versus 6.6 ± 1.6; P = .00002). However, the amount of irrigating fluid volume was higher in the infusion group (117 ± 37 mL versus 94 ± 41 mL; P = .003). No surge occurred in the infusion group; it occurred a mean of 3.00 ± 4.16 times in the control group (P<.0001). The rate of visual gain, CMT, peripapillary RNFL thickness, phaco time, and amount of phaco energy were comparable in the 2 groups.

CONCLUSION

Gas-forced infusion was safe and effective in controlling surge and increased the safety, ease, and speed of coaxial phacoemulsification.

Risk factors for endothelial cell loss after phacoemulsification: comparison in different anterior chamber depth groups

Purpose

To assess the risk factors for endothelial cell loss after phacoemulsification with implantation of intraocular lens according to anterior chamber depth (ACD).

Methods

This prospective study included 94 eyes of 94 patients undergoing phacoemulsification cataract surgery. To assess the risk factors for corneal endothelial cell loss, we examined seven variables at 1 day, 1 week, 6 weeks, and 12 weeks postoperatively in each ACD-stratified group.

Results

Multiple linear regression analysis showed that the only variable influencing the percentage decrease in corneal endothelial cell density throughout the postoperative follow-up period in the long ACD group (ACD III) was nucleosclerosis. The variables influencing the percentage decrease in corneal endothelial cell density in the short ACD group (ACD I) at one day and one week postoperatively were corneal incisional tunnel length and nucleosclerosis.

Conclusions

Risk factors for endothelial cell loss after phaoemulsification were different according to ACD. Long corneal tunnel length can be one of the risk factors for endothelial cell loss in short ACD eyes.

Perioperative modulating factors on astigmatism in sutured cataract surgery

Purpose

To evaluate the factors that affect postoperative astigmatism and post-suture removal astigmatism, and to evaluate the risk factors associated with astigmatism axis shift.

Methods

We performed a retrospective chart review of 130 eyes that had undergone uneventful phacoemulsification cataract surgery. Preoperative astigmatism was divided into four groups (Groups I, II, III, and IV) according to the differences between the axis of preoperative astigmatism (flattest axis) and the incision axis (105 degrees). We analyzed the magnitude and axis of the induced astigmatism after the operation and after suture removal in each group. We also analyzed the factors which affected the postoperative astigmatism and post-suture removal astigmatism in each sub-group of Groups I, II, III, and IV, excluding postoperative or post-suture removal axis shift (specifically, Group I_WAS, II_WAS, III_WAS, and IV_WAS). We identified the variables associated with the prevalence of postoperative astigmatism axis shift and those associated with the prevalence of post-suture removal axis shift.

Results

An increase in the magnitude of postoperative astigmatism was associated with an increase in the preoperative magnitude of astigmatism in Groups I_WAS, II_WAS, and III_WAS (p<0.05), and with an increase in the corneal tunnel length in Group I_WAS. A decrease in the magnitude of postoperative astigmatism was associated with an increase in the corneal tunnel length in Groups III_WAS and IV_WAS (p<0.05). An increase in the magnitude of post-suture removal astigmatism was associated with an increase in the magnitude of postoperative astigmatism in Groups I_WAS and IV_WAS (p<0.05), and with late suture removal in Group IV_WAS (p<0.05). A decrease in the magnitude of post-suture removal astigmatism was associated with late suture removal in Groups I_WAS and II_WAS. A logistic regression analysis showed that the prevalence of post-suture removal astigmatism axis shift was associated with increased corneal tunnel length, decreased magnitude of postoperative astigmatism, and early suture removal.

Conclusions

In order to reduce postoperative and post-suture removal astigmatism, we recommend a short corneal tunnel length and late suture removal in patients with Group I_WAS characteristics, late suture removal in Group II_WAS-like patients, long corneal tunnel length in Group III_WAS-like patients, and long corneal tunnel length and early suture removal in patients with characteristics of Group IV_WAS.

Comparison of fourier-domain and time-domain optical coherence tomography for assessment of corneal thickness and intersession repeatability

PURPOSE

To compare Fourier-domain optical coherence tomography (FD-OCT) with time-domain OCT (TD-OCT) for agreement in corneal pachymetry in the central (2-mm) zone and paracentral (2- to 5-mm) zone, minimum corneal thickness, and instrument intersession reliability in candidates with normal cornea.

DESIGN

Prospective comparative trial.

METHODS

The study was performed at a tertiary care ophthalmic hospital. One hundred normal candidates with no ocular pathology except mild refractive error were included. FD-OCT and TD-OCT were used for pachymetric analysis within 15 minutes of each other. Repeat testing on both machines was done on the next day. One eye from each patient was randomly selected for analysis of both comparison and reliability.

RESULTS

The mean thickness was significantly more for FD-OCT (difference being 5.8, 11.1, and 19.2 mum for central, paracentral, and minimal thickness). Highest correlation, best linear fit, and smallest range of 95% limits of agreement (LoA) was seen for central corneal thickness, followed by paracentral and minimum corneal thickness (R(2) values for the 3 best fit lines were 0.93, 0.86, and 0.58, respectively). In terms of intersession reliability, FD-OCT was better (coefficients of reliability <1.5% vs 4.5% of TD-OCT) with smaller 95% LoA range, suggesting its better performance.

CONCLUSIONS

The corneal thickness measurements between TD-OCT and FD-OCT were highly correlated but not similar. Conversion equations may be used for central and paracentral, but not for minimum, corneal thickness. Even though both the OCT instruments had good reliability, FD-OCT was better.