Manual nucleofragmentation and endothelial cell loss

Corneal Endothelial Characteristics, Central Corneal Thickness, and Intraocular Pressure in a Population of Chinese Age-Related Cataract Patients

Purpose

To describe corneal endothelial characteristics, central corneal thickness, and intraocular pressure in a population of Chinese age-related cataract patients and to determine the effects of age, gender, hypertension, and body mass index (BMI).

Methods

1551 eyes were examined preoperatively. The parameters measured were endothelial cell density (CD), average cell area (CA), coefficient of variation (CV), cell hexagonality (HEX), central corneal thickness (CCT), intraocular pressure (IOP), and axial length (AL).

Results

There were significant differences in CV and BMI between genders. There was a significant decrease in CD, CCT, and IOP and, conversely, an increase in CA and BMI with increasing age. The patients who suffered from hypertension had bigger CA, less CD, and lower HEX than the patients who did not suffer from hypertension. CD has a negative correlation with age and CV and a positive correlation with CCT, CCT has a positive association with CD and IOP, and IOP had a negative relationship with age and a positive relationship with CCT, CA, and HEX.

Conclusions

Normative data for the corneal endothelium, central corneal thickness, and intraocular pressure in the normal age-related cataract patients are reported which will serve as a baseline for comparative studies about cataract.

Phacoemulsification with posterior chamber intraocular lens versus extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens for age-related cataract

BACKGROUND

Age-related cataract is one of the leading causes of blindness worldwide. Therefore, it is important to establish the most effective surgical technique for cataract surgery.

OBJECTIVES

The aim of this review is to examine the effects of two types of cataract surgery for age-related cataract: phacoemulsification and extracapsular cataract extraction (ECCE).

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2013), EMBASE (January 1980 to May 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1970 to May 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 May 2013.

SELECTION CRITERIA

We included randomised controlled trials of phacoemulsification compared to ECCE for age-related cataract.

DATA COLLECTION AND ANALYSIS

Two authors independently selected and assessed all studies. We defined two primary outcomes: 'good functional vision' (presenting visual acuity of 6/12 or better) and 'poor visual outcome' (best corrected visual acuity of less than 6/60) at three and 12 months after surgery. We also collected data on intra and postoperative complications, and the cost of the procedures.

MAIN RESULTS

We included 11 trials in this review with a total of 1228 participants, ranging from age 45 to 94. The studies were generally at unclear risk of bias due to poorly reported trial methods. No study reported presenting visual acuity, so we report both uncorrected (UCVA) and best corrected visual acuity (BCVA). Studies varied in visual acuity assessment methods and time frames at which outcomes were reported. Participants in the phacoemulsification group were more likely to achieve UCVA of 6/12 or more at three months (risk ratio (RR) 1.81, 95% confidence interval (CI) 1.36 to 2.41, two studies, 492 participants) and one year (RR 1.99, 95% CI 1.45 to 2.73, one study, 439 participants). People in the phacoemulsification group were also more likely to achieve BCVA of 6/12 or more at three months (RR 1.12, 95% CI 1.03 to 1.22, four studies, 645 participants) and one year (RR 1.06, 95% CI 0.99 to 1.14, one study, 439 participants), but the difference between the two groups was smaller. No trials reported BCVA less than 6/60 but three trials reported BCVA worse than 6/9 and 6/18: there were fewer events of this outcome in the phacoemulsification group than the ECCE group at both the three-month (RR 0.33, 95% CI 0.20 to 0.55, three studies, 604 participants) and 12-month time points (RR 0.62, 95% CI 0.36 to 1.05, one study, 439 participants). Three trials reported posterior capsule rupture: this occurred more commonly in the ECCE group than the phacoemulsification group but small numbers of events mean the true effect is uncertain (Peto odds ratio (OR) 0.56, 95% CI 0.26 to 1.22, three studies, 688 participants). Iris prolapse, cystoid macular oedema and posterior capsular opacification were also higher in the ECCE group than the phacoemulsification group. Phacoemulsification surgical costs were higher than ECCE in two studies. A third study reported similar costs for phacoemulsification and ECCE up to six weeks postoperatively, but following this time point ECCE incurred additional costs due to additional visits, spectacles and laser treatment to achieve a similar outcome.

AUTHORS' CONCLUSIONS

Removing cataract by phacoemulsification may result in a better visual acuity compared to ECCE, with a lower complication rate. The review is currently underpowered to detect differences for rarer outcomes, including poor visual outcome. The lower cost of ECCE may justify its use in a patient population where high-volume surgery is a priority, however, there are a lack of data comparing phacoemulsification and ECCE in lower-income settings.

The effects of corneal parameters on the assessment of endothelial cell density in the elderly eye

BACKGROUND

The possible impact of corneal thickness, curvature, and size on the measurement of endothelial cell density (ECD) has largely been ignored in the normal eye. The aim of this study was to investigate the possible impact of the main corneal parameters on the analysis of ECD values at the central, superior, and temporal parts of the corneal surface.

METHODS

All 75 participants (52 females, 23 males) were assessed as part of a pre-cataract surgery investigation. The mean age was 75.7 (SD 10.9) years. Confocal microscopy was used to measure ECD and the percentage of six sided cells at the central, superior, and temporal parts of the cornea. The Orbscan II topography system was used to measure corneal thickness, topography, and horizontal corneal diameter.

RESULTS

The mean central ECD measured was 2488 (SD 301) cells/mm(2), compared with 2525 (SD 505) cells/mm(2) in the temporal cornea and 2639 (SD 398) cells/mm(2) in the superior cornea. The regional differences in ECD were not significant (p>0.14). The central ECD was significantly correlated to the central (mean 0.593 (SD 0.039) mm, p = 0.021) as well as the temporal (0.628 (SD 0.039) mm, p<0.001) and the superior corneal thickness (SD 0.644 (SD 0.048) mm, p = 0.018). The mean corneal curvature at the centre (7.7 (SD 0.34) mm, p = 0.002) as well as 3 and 5 mm from the apex was significantly related to ECD (p = 0.008 and p = 0.009, respectively).

CONCLUSIONS

The study suggests that in an older population, lower ECD values would be expected in thinner and/or steeper corneas.

Forceps-guided nuclear cleavage cataract extraction

We introduce a manual nuclear fragmentation technique, forceps-guided nuclear cleavage. A 5.5 to 7.0 mm superior scleral incision is started 1.5 mm posterior to the limbus. Two additional 1.0 mm paracenteses are made at 3 and 9 o'clock in clear cornea close to the limbus. A continuous curvilinear capsulorhexis (CCC) is created; in most cases, 4 to 5 radial relaxing incisions are made in the CCC. The anterior and equatorial cortex and epinucleus are removed with 2-handed irrigation/aspiration via the 2 paracenteses with the nucleus in the capsular bag. The nucleus is prolapsed into the anterior chamber. A nucleus hook is inserted via the 3 o'clock paracentesis and applied to the 6 o'clock nuclear equator to hold the nucleus. A nucleus cleaving forceps is inserted through the upper incision to the 12 o'clock equator of the nucleus and advanced to one-third depth of the nucleus. The forceps is relaxed while the nucleus is cleaved in half.

Behavior of corneal endothelial density over a lifetime

PURPOSE

To define a behavioral model of corneal endothelial density over a lifetime, determine its values, construct a graphic representation, and show the probabilities of occurrence using modified prognosis ranges.

SETTING

A private clinic in Brazil.

METHODS

This retrospective study comprised 784 corneal specular microscopy examinations without regard to race, sex, or age and without a history or pathologies that would alter the endothelium. Endothelial density results were grouped by decades according to patient age. Projections of mean densities and standard deviations by decade were calculated by adjusting the model by variable. The probability of occurrence of the endothelial densities was calculated (P <.05).

RESULTS

The endothelial density over time followed a decreasing linear model (correlation coefficient -0.993). As the endothelial density decreased, the standard deviation tended to increase. The probability of occurrence of an endothelial density of less than 2000 cells/mm(2) was higher from the seventh decade on.

CONCLUSIONS

Knowing the representative values of endothelial density and the probabilities of occurrence over a lifetime can help surgeons determine the risk to the cornea of anterior segment surgery. It can also be useful in following eyes with disease affecting the endothelium and in preparing and evaluating corneal specular microscopy reports.

Quarters extraction technique for manual phacofragmentation(1)

In the quarters extraction technique, the nucleus is manually split and the fragments then removed. A 5.5 to 6.5 mm sclerocorneal single-plane incision is made. After capsulorhexis, hydrodissection, hydrodelineation, and surface cortex aspiration, the edge of the nucleus is prolapsed into the anterior chamber. The front quarter of the nucleus is cut and removed with a nucleus puncher. A corner of the remaining three quarters of nucleus is wedged into the wound and rotated out with a claw vectis. Among the initial 120 cases, there were no posterior capsule ruptures, and the mean endothelial cell loss at 3 months was 8.7% +/- 6.5% (SD). Because there is no need to deeply insert instruments at the time of nuclear fragmentation, this technique can be performed safely and easily in most cases except in eyes with very large nuclei.

Small incision extracapsular cataract surgery with manual phacotrisection

PURPOSE

To evaluate the safety and efficacy of small incision extracapsular cataract extraction (ECCE) using the manual phacotrisection technique.

SETTING

Department of Ophthalmology, Turgut Ozal Medical Center, InönüUniversity, Malatya, Turkey.

METHODS

Fifty-nine eyes of 54 patients had small incision ECCE by the manual phacotrisection technique. Mean follow-up was 10 months. After capsulorhexis and hydrodissection were performed, the endonucleus was prolapsed into the anterior chamber and trisected using an anteriorly positioned triangular trisector and posteriorly placed solid vectis. Pieces were extracted with a forceps through a small incision.

RESULTS

Postoperatively, best spectacle-corrected visual acuity of 20/40 or better was achieved in 48 eyes (83%) and of 20/25 or better in 28 eyes (47%). The most frequent intraoperative complication was posterior capsule rupture (n = 5). Of eyes that developed posterior capsule rupture, 3 had vitreous loss and 2 had implantation of an anterior chamber intraocular lens (IOL). In 44 eyes, the IOL was implanted in the bag and in 12 eyes, in the ciliary sulcus. The most significant postoperative complication was transient corneal edema, which developed in 32 eyes (54%). No permanent complications (e.g., corneal endothelial decompensation) occurred in any case.

CONCLUSIONS

Manual phacotrisection has several advantages such as nucleus safety, less dependence on assistant personnel, the elimination of the phaco machine, and cost effectiveness.

Intraocular lidocaine in phacoemulsification: an endothelium and blood-aqueous barrier permeability study

OBJECTIVE

To evaluate the effects of intraocular lidocaine hydrochloride (HCI) on the corneal endothelium and of blood-aqueous barrier (BAB) permeability in ultrasound phacoemulsification.

DESIGN

Nonrandomized, comparative trial.

PARTICIPANTS

Sixty patients who underwent uneventful, single-surgeon, clear cornea phacoemulsification were studied prospectively.

METHODS

Sub-Tenon's anesthesia was administered to 30 patients (group 1), and intraocular lidocaine hydrochloride was administered to an additional 30 patients (group 2). An endothelial study of at least 120 cells per patient, using a noncontact specular microscope and a digital image analysis system, was performed before surgery and 1 month after surgery. Blood-aqueous barrier permeability was evaluated preoperatively and postoperatively (48 hours, 1 week and 1 month) using a laser flare meter.

MAIN OUTCOME MEASURES

Endothelial parameters (cell density, hexagonality, and coefficient of variation in cell area) and BAB permeability.

RESULTS

No significant differences were found between groups when comparing the postoperative changes produced in endothelial cell density (95% confidence interval [CI], 0.46, 4.7; P = 0.10), hexagonality (95% CI, -2.5, 3.5; P = 0.72), and coefficient of variation in cell area (95% CI, -8.3, 4.6; P = 0.57). A multivariate study detected no significant differences in mean flare values between groups during follow-up (P = 0.40). No clinically significant differences were found between mean preoperative and 1 month postoperative flare values in either group.

CONCLUSIONS

The recovery of BAB permeability 1 month after surgery seems to suggest that no additional inflammation was induced by intraocular lidocaine HCI. The fact that no differences in postoperative changes in endothelial parameters were found between groups indicates that no further corneal endothelial damage (other than that caused by surgical manipulation) was incurred. According to our results, intracameral lidocaine HCI appears to be safe for the average phacoemulsification patient in the absence of ocular pathologic conditions.

Manual tunnel incision extracapsular cataract extraction using the sandwich technique

Small incision extracapsular cataract extraction (ECCE) using the sandwich technique is described. After capsulorhexis, hydrodissection, and hydrodelineation, the endonucleus is moved into the anterior chamber and extracted by sandwiching it between the irrigating vectis and iris spatula. In a series of 37 eyes, most achieved a best corrected visual acuity of 5/10 or better postoperatively. Complications were posterior capsule rupture, vitreous loss, and transient corneal edema. Small incision ECCE using the sandwich technique is safe, easy, and does not require expensive instrumentation.