Refractive cataract surgery

Differential time-course tear film quantitative changes following limbal relaxing incisions

Background

The study aims at evaluating the time-course changes of pre-corneal tear film after simultaneous phacoemulsification and limbal relaxing incisions (LRIs) performed in 2 groups of patients; group-A had vertical and group-B had horizontal LRIs.

Methods

Fourty-two eyes of 28 patients with co-existing cataract and corneal astigmatism were studied before and after simultaneous cataract surgery and LRIs (at weeks 1, 4 and 12), patients were classified into 2 groups according to the orientation of LRIs; vertical (A) and horizontal (B) groups. Pre-corneal tear film stability was assessed by measuring the tear break-up time (TBUT) and the tear volume was determined using Schirmer’s I test (Basic Schirmer’s test; BST), both preoperatively and postoperatively.

Results

TBUT was significantly reduced in both the study groups (P = 0.001) without significant reduction regarding basic Schirmer’s test values except for the first postoperative week in the horizontal LRI group-B (P = 0.04).

Conclusions

Precorneal tear film stability is altered in the early postoperative period after simultaneous cataract and LRI incisions shown by TBUT measurement values. These changes do not appear to differ significantly depending on the orientation of LRI incisions.

Three Methods for Correction of Astigmatism during Phacoemulsification

PURPOSE

To compare the safety and efficacy of three methods for correcting pre-existing astigmatism during phacoemulsification.

METHODS

This prospective, comparative, non-randomized study was conducted from March 2010 to January 2011, and included patients with keratometric astigmatism ≥1.25 D undergoing cataract surgery. Astigmatism was corrected using the following approaches: limbal relaxing incisions (LRI) on the steep meridian, extension and suturing of the phaco incision created at the steep meridian (extended-on-axis incision, EOAI), and toric intraocular lens (tIOL) implantation. Keratometric and refractive astigmatism were evaluated 1, 8, and 24 weeks postoperatively.

RESULTS

Eighty-three eyes of 72 patients (35 male and 37 female) with mean age of 62.4 ± 14.3 (range, 41-86) years were enrolled. The astigmatism was corrected by using the LRI, EOAI and tIOL implantation methods in 17, 33 and 33 eyes, respectively. Postoperative uncorrected distance visual acuity (UDVA) was significantly improved in all three groups. The difference in postoperative UDVA was not statistically significant among the study groups throughout follow-up except at week 24, when UCVA was significantly better in the tIOL group as compared to the EOAI group (P = 0.024). There is no statistically significant difference of correction index and index of success between three groups at week 24 (P = 0.085 and P = 0.085 respectively).

CONCLUSION

There was no significant difference in astigmatism reduction among the three methods of astigmatism correction during phacoemulsification. Each of these methods can be used at the discretion of the surgeon.

Limbal Relaxing Incisions to Correct Corneal Astigmatism During Phacoemulsification

PURPOSE

To evaluate the safety and efficacy of limbal relaxing incisions for the correction of corneal astigmatism during phacoemulsification.

METHODS

Fifty eyes of 37 patients (mean age 66.5 years, range: 45 to 80 years) with cataract and coexisting topographic astigmatism were included in the study. Eyes were randomly divided into two groups: eyes that underwent cataract surgery with limbal relaxing incisions (cataract LRI group) and eyes that underwent cataract surgery only (control group). All limbal relaxing incisions were performed during phacoemulsification. Best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), and corneal topography were recorded preoperatively and 1, 3, and 6 months postoperatively.

RESULTS

A statistically significant improvement in BSCVA was seen in the cataract LRI eyes from 0.9 +/- 0.7 preoperatively to 0.1 +/- 0.1 at 1, 3, and 6 months postoperatively (P < .01). A statistically significant improvement in BSCVA was seen in control eyes from 0.8 +/- 0.6 before surgery to 0.2 +/- 0.2 at 1, 3, and 6 months after surgery (P < .01). No difference in postoperative BSCVA was noted between the groups. A statistically significant reduction in the mean topographic astigmatism was seen in the cataract LRI eyes from 1.93 +/- 0.58 diopters (D) preoperatively to 1.02 +/- 0.60 D 6 months postoperatively (P < .05). The control eyes did not show a statistically significant change in topographic astigmatism.

CONCLUSIONS

Limbal relaxing incisions performed during phacoemulsification surgery appear to be a safe, effective, and stable procedure to reduce pre-existing corneal astigmatism.

Choosing the location of corneal incision based on preexisting astigmatism in phacoemulsification

PURPOSE

To investigate the best location of clear-cornea incision in phacoemulsification, depending on preexisting corneal astigmatism.

DESIGN

Randomized clinical trial and noncomparative interventional case series.

METHODS

A total of 574 patients in five stages were assigned to the following incisions: superior or temporal (n = 89), superior (n = 141), superior or superior plus relaxing (n = 102), nasal or temporal (n = 156), and incisions based on applying conclusions of preceding and current studies (n = 86). Visual acuity, refraction, biomicroscopy, keratometry, and videokeratography (Fourier analysis) were performed before and after phacoemulsification and intraocular lens implantation (3.5-mm incision). main outcome measures: Corneal refractive and surface regularity index change between preoperative and 6-month postoperative examination. Visual acuity at 6 months.

RESULTS

In patients without corneal astigmatism, corneal changes induced were greater in superior than temporal incision. After a superior incision (preoperative steep axis at 90 degrees), a shift of the axis 90 degrees away was less likely with at least 1.5 diopters of astigmatism. A perpendicular relaxing limbal incision decreased corneal changes. Nasal incision induced greater corneal change than temporal incision (preoperative steep axis at 180 degrees). A shift of this axis 90 degrees away was more likely with astigmatism < 0.75 diopters in temporal incision and < 1.25 diopters in nasal incision.

CONCLUSIONS

Superior incision is recommended with at least 1.5 diopters of astigmatism and steep axis at 90 degrees. Temporal incision is recommended with astigmatism < 1.5 diopters and steep axis at 90 degrees, negligible astigmatism, or astigmatism < 0.75 diopters and steep axis at 180 degrees. Nasal incision is recommended with at least 0.75 diopters of astigmatism and steep axis at 180 degrees.

Topical anesthesia--a new approach to cataract surgery

Patients undergoing cataract surgery with the use of topical anesthesia experience less pain, can return home faster, and avoid the need for an eye patch, which can cause depth perception problems. Patient education performed by the perioperative nurse significantly affects patients' experience and recovery. This article discusses the history of cataract surgery, etiology of cataract formation, and traditional anesthetic choices. The patient selection process relative to topical anesthesia is defined, and the patient's experience throughout the perioperative phases of cataract extraction is described.

Videokeratoscopy of recipient peripheral corneas in combined penetrating keratoplasty, cataract extraction, and lens implantation

PURPOSE

We performed a prospective clinical trial to evaluate computerized videokeratoscopic analysis of the peripheral recipient cornea in intraocular lens power calculations for triple procedures: penetrating keratoplasty, cataract extraction, and intraocular lens insertion.

METHODS

Patients with Fuchs' dystrophy underwent consecutive triple procedures. Surgery was performed in 16 eyes by a single surgeon (O.N.S.) using a single technique. If videokeratoscopic analysis disclosed dioptric powers greater than 40 diopters in the circumference of the corneal map, the surgeon's average postoperative central corneal power of 46 diopters was used with the regression formula. If dioptric powers less than 40 diopters were detected in the circumference of the corneal map, 45 diopters was used to avoid postoperative hyperopic shifts and to decrease deviation from intended refractive error. Refraction and videokeratoscopic analysis were performed six months after suture removal (18 to 24 months postoperatively).

RESULTS

Analysis of covariance demonstrated that preoperative peripheral videokeratoscopic data of the recipient cornea correlated (P = .0001) with postoperative central corneal power, whereas preoperative central corneal power of the recipient cornea did not correlate (P = .35). Deviation from intended refraction (range, -2.54 to +1.22 diopters) was within 2 diopters in 14 eyes (88%) and within 3 diopters in all eyes. No patients had anisometropia greater than 3 diopters.

CONCLUSION

Preoperative data from computerized videokeratoscopic analysis of the recipient peripheral cornea correlated with postoperative central corneal power, and improved postoperative refractive outcomes compared with previously reported results of triple procedures.