[Blood-aqueous barrier after phacoemulsification with posterior chamber lens implantation; foldable acrylate lens vs PMMA lens-- a clinical study on 46 eyes]

Factors influencing aqueous flare after cataract surgery and its evaluation with laser flare photometry

Despite the refinement of modern cataract surgery, postoperative inflammation still constitutes a substantial amount of visual morbidity worldwide. A surrogate for intraocular inflammation and blood-aqueous barrier breakdown can be objectively quantified by Laser flare photometry (LFP). This review outlines the utility of LFP in assessing the assessment of post-cataract surgery inflammation. It highlights the impact of preoperative pathological states such as uveitis and diabetes, intraoperative techniques, including efficient phacoemulsification and direct comparisons between postoperative anti-inflammatory regimes. There is a large interobserver variation in the subjective flare measurement after cataract surgery and the continued use of LFP amongst other objective, noninvasive measurements of intraocular inflammation, particularly in the further development of cataract surgery, is recommended.

Laser flare-cell photometer: principle and significance in clinical and basic ophthalmology

A slit-lamp examination is an indispensable and essential clinical evaluation method in ophthalmology, but, it is qualitative subjective. To complement its weaknesses in making a quantitative evaluation of flare intensity and number of cells in the aqueous humor in the eye, we invented the laser flare-cell photometer in 1988. The instrument enables a non-invasive quantitative evaluation of flare intensity and number of cells in the aqueous with good accuracy and repeatability as well as maneuverability equal to slit-lamp microscopy. The instrument can elucidate the pathophysiology in the blood-aqueous barrier (BAB) function in a variety of ocular disorders. The accuracy of the instrument makes it possible to investigate not only the pathophysiology of intraocular disorders but also the effects of various drugs and surgical procedures in BAB. The instrument does not only lighten the burden on patients in clinical examinations and study but it also helps minimize the sacrifice of experimental animals and improves the reliability of the results by minimizing inter-individual variations through its good repeatability. Here I shall relate how the instrument has been applied to clinical and basic studies in ophthalmology and what novel knowledge its application contributed to pathophysiology in ophthalmology.

Quantification of blood-aqueous barrier breakdown after phacoemulsification in Fuchs' heterochromic uveitis

PURPOSE

To quantify the breakdown of the blood-aqueous barrier (BAB) following phacoemulsification with posterior chamber lens implantation in eyes with Fuchs' heterochromic uveitis (FHU).

PATIENTS AND METHODS

In this retrospective study, 19 eyes of 19 patients with FHU (mean age 38 +/- 14 years) and 35 eyes of 35 patients with senile cataracts (mean age 63 +/- 9 years) underwent phacoemulsification with one-piece PMMA posterior chamber lens implantation. Aqueous flare was quantified using the laser flare-cell meter (LFCM, Kowa FC-1000) following medical pupillary dilation preoperatively and 1, 3, and 5 days, then 1 and 6 weeks and 6 months postoperatively.

RESULTS

Mean preoperative aqueous flare (in photon counts per millisecond) in FHU vs. controls was 11.7 +/- 3.5 vs. 5.8 +/- 1.7. Following cataract surgery, mean aqueous flare increased to 27.8 +/- 4.4 vs. 16.0 +/- 4.5 on day 1, decreased to 23.6 +/- 4.0 vs. 11.8 +/- 3.5 on day 3, and to 18.0 +/- 3.0 vs. 9.5 +/- 1.7 on day 5. In FHU eyes, it was 13.9 +/- 2.7 after 1 week, and had returned to preoperative levels after 6 weeks (10.9 +/- 2.5) and remained stable for up to 6 months (mean 10.3 +/- 2.2). Pre- and postoperatively, aqueous flare values were 2-3 times higher in FHU eyes than in control eyes with senile cataract (p = 0.01). No postoperative complications such as fibrin formation, synechiae, macrophages on the intraocular lens optic or endophthalmitis were observed in any of the patients.

CONCLUSIONS

BAB breakdown following phacoemulsification with posterior chamber lens implantation is relatively mild in eyes with FHU and the BAB appears to be fully reestablished to preoperative levels 6 weeks postoperatively, explaining the usually good outcome of cataract surgery in this condition.

Results and complications of hydrophobic acrylic vs PMMA posterior chamber lenses in children under 17 years of age

PURPOSE

To compare results and complications of implantation of hydrophobic acrylic foldable intraocular lenses in children with those of polymethylmethacrylate (PMMA) intraocular lenses.

METHODS

In a retrospective study, we analyzed results of cataract surgery with posterior chamber lens implantation in 30 eyes of 30 patients aged 1-16 years. In 10 eyes, acrylic (Alcon AcrySof) intraocular lenses, and in 20 eyes, single-piece PMMA posterior chamber lenses were implanted. Indications for cataract surgery (blunt or penetrating trauma, zonular cataract, cataracta polaris posterior, posterior lenticonus) and mean age at implantation were comparable in the two groups. Mean patient age at surgery was 8.6+/-4.6 years (range 3-16 years) for the acrylic vs 6.3+/-4.3 years (range 1-16 years) for the PMMA group. Mean follow-up was 1.0+/-0.7 years (range 0.1-2.2 years) in the acrylic group and 1.8+/-1.5 years (range 0.1-5.7 years) in the PMMA group. Primary anterior vitrectomy was performed in 7 eyes in the PMMA group and in 3 eyes in the acrylic group. In addition, one additional posterior capsulorhexis without anterior vitrectomy was performed in each group. Primary outcome measure was the occurrence of postoperative "complications" (fibrin, synechiae, posterior capsular opacification). For statistical evaluation, the Fisher exact test was used.

RESULTS

When evaluating all complications together (at least one complication vs no complication), there were significantly less complications in the acrylic group (2 of 10 vs 15 of 20; p=0.007. For early complications (postoperative fibrin, synechiae) the difference was also significant (1 of 10 in the acrylic vs 11 of 20 in the PMMA group; p=0.02). The rate of posterior capsular opacification necessitating YAG capsulotomy was lower in the acrylic group (1 of 10 eyes) than in the PMMA group (7 of 20 eyes), but the difference did not reach statistical significance ( p=0.67). The postoperative time point of YAG capsulotomy was 21 months in the acrylic group and 19+/-10 months (range 6-33 months) in the PMMA group. IOL dislocation was not observed in any of the patients. Postoperative visual acuity was comparable in the two groups: 0.57+/-0.35 (0.03-1.0) in the acrylic vs 0.39+/-0.34 (0.001-0.9) in the PMMA group ( p=0.83).

CONCLUSIONS

Implantation of hydrophobic acrylic intraocular lenses in the capsular bag in children may be associated with less postoperative complications compared with implantation of PMMA lenses. This appears also to be true in children under age 6 years. The visual results seem comparable and correspond mainly to the underlying ocular pathology.

Short-term blood-aqueous barrier breakdown after implantation of the 1CU accommodative posterior chamber intraocular lens

PURPOSE

To quantify intraocular inflammation after phacoemulsification with implantation of an accommodative posterior chamber intraocular lens (IOL).

SETTING

Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen, Germany.

METHODS

Twenty cataractous eyes of 20 patients without preexisting blood-aqueous barrier (BAB) deficiencies or previous intraocular surgery were included in this study. The mean age of the patients was 64.6 years +/- 16.0 (SD). A single surgeon performed phacoemulsification through a superior sclerocorneal tunnel incision and implantation of a 1CU IOL (HumanOptics AG) though a 3.2 mm incision. The haptics of the single-piece acrylic 1CU lens are designed for anterior optic movement following ciliary muscle contraction. The postoperative treatment was standardized. Postoperative BAB breakdown was quantified by laser flare photometry (FC-1000, Kowa) at 1 day, 1 and 4 weeks, and 3 and 6 months.

RESULTS

The mean aqueous flare was 6.3 photons/ms +/- 3.0 (SD) (range 4.0 to 12.2 photons/ms) 1 day postoperatively, with 64% of patients having normal aqueous flare values (<8.0 photons/ms). One week after surgery, the mean aqueous flare was 5.3 +/- 2.8 photons/ms (range 2.0 to 10.5 photons/ms). Four weeks postoperatively, aqueous flare was normal in all patients and remained stable below the normal limit for up to 6 months (mean 3.3 +/- 1.2 months; range 2.0 to 5.4 months). The number of aqueous cells did not increase at any follow-up and was normal in all eyes. No postoperative complications such as fibrin formation, synechias, macrophages on the IOL optic, or endophthalmitis were observed.

CONCLUSIONS

Phacoemulsification with implantation of the 1CU accommodative IOL led to minimal and short-lasting BAB alteration. No signs of persistent inflammation or pigment dispersion were detected.