Norihito Gotoh

Analysis of surface whitening of extracted hydrophobic acrylic intraocular lenses

PURPOSE: To identify the cause of light scattering on the surface (ie, whitening) of extracted AcrySof intraocular lenses (IOLs). SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. METHODS: Dislocated IOLs extracted from 3 patients were stored and the IOL surfaces examined under light microscopy. The effect of whitening on visual function was evaluated by measuring light transmission with a spectrophotometer. To determine the cause of opacification, the IOLs were examined for calcium phosphate deposits using an electron probe X‐ray microanalyzer. The IOL surface, including the presence of organic deposits and evidence of hydrolysis, was also examined by Fourier‐transform infrared spectrophotometry. The IOLs were then dried, immersed again in physiological saline, and serially examined for changes in opacification. RESULTS: The optic surfaces of all IOLs had opacification due to whitening. Light transmission in the visible range of 360 to 800 nm was 4% less than that of unused IOLs. The X‐ray microanalysis showed no calcium phosphate deposits. Fourier‐transform infrared spectrophotometry of the IOL optic material showed no evidence of hydrolysis. Opacification disappeared after the IOLs were dried and then reappeared over time when the IOL was immersed again in physiologic saline. CONCLUSIONS: The findings strongly suggest that whitening of the hydrophobic acrylic IOL was due to trace water molecules that infiltrate the optic. Within the 3‐dimensional network of the polymeric lens material, the molecules are too small to form observable voids but can form water aggregates of sufficient size to scatter visible light, causing opacification (ie, whitening).

Comparison of anterior capsule contraction between 5 foldable intraocular lens models.

PURPOSE: To compare anterior capsule contraction in cataract patients having implantation of 1 of 5 foldable intraocular lens (IOL) models and evaluate lens epithelial cell (LEC) adhesion to each model. SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. METHODS: This study comprised 115 patients (126 eyes) without systemic or ocular complications who had phacoemulsification with IOL implantation. The eyes were randomly assigned to receive 1 of the following IOLs: acrylic MA60BM (Alcon), SA60AT (Alcon), AR40e (Advanced Medical Optics), or YA‐60BBR (Hoya) or a silicone AQ310NV (Canon). Two weeks and 1, 3, and 6 months postoperatively, the anterior capsule opening area was measured using an anterior segment analysis system (EAS‐1000, Nidek) and the percentage of anterior capsule contraction was compared for each postoperative period and IOL. Cell adhesion to each IOL type was evaluated using LECs from albino rabbits. RESULTS: The mean age of the patients was 73.6 years ± 5.6 (SD). Eyes with the AQ310NV and AR40e IOLs had statistically significantly greater anterior capsule contraction. The rabbit study showed statistically significantly less LEC adhesion on these 2 IOL models. CONCLUSIONS: Anterior capsule contraction was significantly greater with the AQ310NV and AR40e IOLs than with the other IOLs. Results indicate that cell adhesion to the IOL is an important factor in preventing anterior capsule contraction.

Efficacy of ophthalmic nonsteroidal antiinflammatory drugs in suppressing anterior capsule contraction and secondary posterior capsule opacification

PURPOSE: To evaluate the efficacy of ophthalmic nonsteroidal and steroidal antiinflammatory drugs in preventing anterior capsule contraction and secondary posterior capsule opacification (PCO) using an experimental cataract model. SETTING: Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan. METHODS: Eight‐week‐old albino rabbits weighing about 2 kg each had phacoemulsification and intraocular lens implantation. After surgery, the rabbits were divided into 3 treatment groups: diclofenac sodium ophthalmic solution, bromfenac sodium ophthalmic solution, and betamethasone ophthalmic solution. In each group, the ophthalmic solution was applied to the left eye of each rabbit twice daily; the right eye served as an untreated control. To evaluate anterior capsule contraction, the percentage of incised anterior capsule opening area was calculated on diaphanoscopic images obtained with an EAS‐1000 anterior segment analyzer. For evaluation of PCO, a tissue section was stained with hematoxylin–eosin and observed under a light microscope. The PCO was quantified on the basis of the thickness of the lens epithelial cell layer on the central subcapsular area and compared among groups. RESULTS: Fifteen albino rabbits were used in the study. Treatment with diclofenac sodium and bromfenac sodium ophthalmic solution prevented progression of anterior capsule contraction and PCO. Treatment with bromfenac ophthalmic solution did not prevent either complication. CONCLUSION: Postoperative treatment with ophthalmic nonsteroidal antiinflammatory drug solutions prevented anterior capsule contraction and PCO in rabbit eyes.

Influence of intraocular lens implantation on anterior capsule contraction and posterior capsule opacification

Purpose To evaluate whether and how intraocular lens (IOL) implantation influences the development of anterior capsule contraction and posterior capsule opacification (PCO). Setting Department of Ophthalmology, Dokkyo Medical University, Mibu, Tochigi, Japan. Design Experimental study. Methods Phacoemulsification was performed in 8‐week‐old white rabbits. A hydrophobic acrylate IOL (12.5 mm) (YA‐60BBR) was implanted in 1 eye and no IOL was implanted in the fellow eye. Slitlamp microscopy and anterior segment analysis were performed to evaluate anterior capsule contraction after the surgery. Four weeks postoperatively, sections of the eyes were made, and the thickness of the proliferated lens epithelial cell (LEC) layer at the posterior capsule was measured to assess the PCO. In addition, LECs from white rabbits were cultured in medium containing 50% aqueous humor or in medium containing 50% saline to determine the influence of the aqueous humor on LECs and to compare the degree of LEC proliferation. Results Starting 2 weeks after surgery, anterior capsule contraction progressed more significantly in the IOL group than in the group without IOLs. Four weeks postoperatively, LEC thickness at the posterior capsule was significantly less in the group without IOLs than in the IOL group. In the culture study, LEC proliferation was more inhibited in the aqueous humor group than in the saline group. Conclusions Progression of anterior capsule contraction and PCO is less likely in aphakic eyes than in IOL‐implanted eyes. The mechanism of prevention may involve aqueous humor–induced inhibition of LEC proliferation. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.