The influence of the incision length on the early postoperative intraocular pressure following cataract surgery

A comparative study of postoperative intraocular pressure changes in small incision vs conventional extracapsular cataract surgery

AIMS

To compare short- and long-term IOP changes in small incision cataract surgery (SICS) vs conventional extracapsular cataract surgery (CECS).

METHODS

A total of 232 eyes of as many patients undergoing cataract surgery were randomized to SICS or CECS. Sixteen eyes had to be excluded out of the study. IOP was recorded preoperatively and postoperatively on day 1, 2, and 7; and then after 1, 3, and 6 months. Only 160 eyes remained under 6-month follow-up, out of which 48 had CECS and remaining 112, SICS. Results were analysed statistically (repeated measure ANOVA, multiple comparisons).

RESULTS

A significantly higher IOP was observed on day 1, 2, and 7 in both types of surgeries as compared to mean preoperative IOP. Variation in rise was more pronounced in CECS (nearly twofold) than in SICS (P<0.05). Maximum decrease in IOP occurred during the first week and it was more rapid in SICS than CECS. At 3 months, IOP was significantly higher than baseline in CECS but significantly lower in SICS. From 3 to 6 months, there was no further decrease in IOP in either type of surgery.

CONCLUSIONS

IOP rises significantly on day one in CECS and SICS and thereafter comes down slightly by day 2 and rapidly by day 7. IOP rise is more pronounced in CECS than in SICS. After 1 week to 3 months, IOP decline is very gradual and thereafter ceases to decrease.

Relationship of immediate intraocular pressure rise to phaco-tip ergonomics and energy dissipation

PURPOSE

To evaluate the rise in intraocular pressure (IOP) after phacoemulsification using a straight microtip or a Kelman microtip and its relationship to phaco energy delivered to the eye.

SETTING

Iladevi Cataract & IOL Research Center, Ahmedabad, India.

METHODS

This prospective randomized study comprised 48 consecutive age- and sex-matched patients with senile cataract. Inclusion criteria included older than 45 years and presence of any type of cataract from grade I to III. The patients were divided into 2 groups: straight microtip and Kelman microtip. Each group comprised 13 men and 11 women. The mean age was 58.29 years +/- 6.46 (SD) in the straight microtip group and 60.05 +/- 8.45 years in the Kelman microtip group. The IOP was measured preoperatively and postoperatively with a pneumotonometer and applanation tonometer. One surgeon performed all operations using a standardized surgical technique and topical anesthesia. The intraoperative mean phaco power and ultrasound (US) time were noted. The effective phaco time (EPT), percentage of IOP rise, and wound-site thermal injury (mild, moderate, or severe) were calculated. The correlation between the EPT and percentage of rise in IOP was evaluated using correlation coefficients and the paired t test.

RESULTS

The mean preoperative IOP was 13.73 +/- 2.89 mm Hg in the straight microtip group and 15.14 +/- 2.60 mm Hg in the Kelman microtip group. The mean US time was 239.4 +/- 1.61 seconds and 238.2 +/- 1.48 seconds, respectively. The mean phaco power was 17.37% +/- 3.28% in the straight microtip group and 17.10% +/- 5.26% in the Kelman microtip group and the mean EPT, 39.06 +/- 2.28 seconds and 40.08 +/- 0.24 seconds, respectively (P =.412). The mean rise in IOP was 111.60% +/- 37.83% in the straight microtip group and 91.29% +/- 31.85% in the Kelman microtip group. The difference between groups was significant (P<.05). The correlation coefficient between the EPT and percentage of IOP rise was significant in both groups: 0.3823, straight microtip group (P<.05); 0.514, Kelman microtip group (P<.01). Wound-site thermal injury was noted in 3 patients in the straight microtip group and 1 patient in the Kelman microtip group.

CONCLUSIONS

Although the amount of phaco energy dissipated in the eye was the same between the 2 groups, the percentage of IOP rise was greater with the straight microtip. The rise in IOP was correlated with the dissipated phaco energy.

Intraocular pressure change after sutureless phacoemulsification and foldable posterior chamber lens implantation

PURPOSE

To investigate the effect on intraocular pressure (IOP) of sutureless scleral and corneal tunnel Kelman phacoemulsification (KPE) with foldable posterior chamber intraocular lens (IOL) implantation.

SETTING

Jules Stein Eye Institute, Los Angeles, California, USA.

METHODS

Preoperative and postoperative (1 and 6 weeks and 6 to 8 months) IOP measurements of 385 consecutive eyes having uneventful phacoemulsification and foldable posterior chamber IOL implantation were reviewed retrospectively. A subset of 193 eyes for which no IOP measurements were missing at any follow-up were analyzed separately.

RESULTS

Mean preoperative IOP was 15.8 mm Hg +/- 0.2 (+/- SE). It dropped postoperatively by 1.3 +/- 0.2 mm Hg at 1 week (P < .001), 2.5 +/- 0.2 mm Hg at 6 weeks (P < .001), and 2.2 +/- 0.2 mm Hg at 6 to 8 months (P < .001). Mean preoperative IOP for the subset without missing data was 16.0 +/- 0.3 mm Hg. It decreased by 1.1 +/- 0.3 mm Hg at 1 week (P < .001), 2.3 +/- 0.2 mm Hg at 6 weeks (P < .001), and 2.2 +/- 0.2 mm Hg at 6 to 8 months (P < .001). Wound construction (scleral versus corneal tunnel), anesthesia type (topical versus posterior orbital injection), the eye operated on, and patient age and sex did not significantly influence the postoperative pressure change. Patients with a preoperative diagnosis of glaucoma had significantly higher 1 week postoperative IOPs; however, the differences were statistically insignificant at 6 weeks and 6 to 8 months.

CONCLUSION

Sutureless KPE with foldable posterior chamber IOL implantation lowered IOP by 1.1 to 2.5 mm Hg for the 6 months immediately following surgery. Glaucoma patients had a statistically significant initial rise in IOP at 1 week.