[Postoperative opacification of posterior chamber intraocular lenses - a review]

Long-term clinical results and scanning electron microscopic analysis of the aspheric, hydrophobic, acrylic intraocular lens CT LUCIA 611P(Y)

Purpose

The aim of this study was to evaluate the clinical outcomes of a novel designed hydrophobic, acrylic, monofocal, fully preloaded intraocular lens (IOL; CT LUCIA 611P) 1 year after implantation. Scanning electron microscopic analysis regarding the optic-haptic junction and sharp edges of the IOL was performed.

Patients and methods

This is a noninterventional, observational prospective study of cataract patients who underwent implantation of the CT LUCIA 611P. Ninety-six eyes of 54 subjects were enrolled. Follow-up included visual acuity assessment, slit lamp examination with special focus on appearance of glistenings and evaluation of posterior capsule opacification (PCO). Scanning electron microscopic analysis of the new designed optic-haptic junction and edges of the IOL was performed.

Results

Best-corrected distance visual acuity increased from mean 0.48 logMAR (range 0.86-0.34) preoperatively to mean 0.02 logMAR (range 0.14 to -0.10) 1 year after surgery. Thirty-eight of 42 subjects' eyes (90.5%), which underwent bilateral surgery with implantation of the IOL, never required glasses for distance again, while 4 (9.5%) required glasses only in rare cases (eg, driving at night). The spherical equivalent was within ±0.50 D in 88 of 96 subjects (91.7%) and within ±0.75 D in 96.9% of cases. Target refraction ±1.00 D was achieved in 100% of subject eyes. No glistenings were reported in any case. From the surgeons' perspective, the wider, thicker optic-haptic transition of the IOL resulted in significantly increased stiffness, which enabled improved centering of the IOL and enhanced rotational stability and refractive predictability and stability and PCO prevention.

Conclusion

The results of this long-term observational study demonstrate the safety and efficacy of the IOL. Because of the completely new designed thicker and stiffer optic-haptic junction regarding improved characteristics of the IOL (stability in the capsular bag), some special attention has to be addressed to the slightly different behavior of the lens during implantation and unfolding process.

Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

This preliminary report was attempted to compare the chemical components of mineral deposits on the surfaces of an opacified intraocular lens (IOL) and a calcified senile cataractous lens (SCL) by vibrational spectral diagnosis. An opacified intraocular lens (IOL) was obtained from a 65-year-old male patient who had a significant decrease in visual acuity 2-years after an ocular IOL implantation. Another SCL with grayish white calcified plaque on the subcapsular cortex was isolated from a 79-year-old male patient with complicated cataract after cataract surgery. Optical light microscope was used to observe both samples and gross pictures were taken. Fourier transform infrared (FT-IR) and Raman microspectroscopic techniques were employed to analyze the calcified deposits. The curve-fitting algorithm using the Gaussian function was also used to quantitatively estimate the chemical components in each deposit. The preliminary results of spectral diagnosis indicate that the opacified IOL mainly consisted of the poorly crystalline, immature non-stoichiometric hydroxyapatite (HA) with higher content of type B carbonated apatites. However, the calcified plaque deposited on the SCL was comprised of a mature crystalline stoichiometric HA having higher contents of type A and type B carbonate apatites. More case studies should be examined in future.

Opacification of a silicone intraocular lens caused by calcium deposits on the optic

We describe opacification of a plate-haptic silicone intraocular lens (IOL) caused by calcification in a diabetic patient with asteroid hyalosis. The IOL was explanted 48 months after uneventful phacoemulsification because opacification of the posterior surface was causing significant visual disturbance. Light and scanning electron microscopy and x-ray spectrometry of the explanted IOL showed the opacification consisted mainly of calcium and phosphate, presumably hydroxyapatite, in the form of precipitations on the posterior surface of the optic.

Ultraviolet radiation absorption of intraocular lenses

OBJECTIVES

To record and compare the spectral transmittance curves of intraocular lenses (IOLs) made out of polymethyl methacrylate (PMMA), acrylic, hydrogel, and silicone from different manufacturers; to evaluate their ultraviolet radiation absorption capacities; and to contrast the recorded transmittance curves with that of the natural lens.

DESIGN

Experimental study.

METHODS

We studied 17 different 21-diopter IOLs. A high-performance spectrophotometer with a diffuse transmittance accessory was employed to measure the transmittance of wavelengths from 200 nm to 800 nm through a 1.5-mm aperture.

MAIN OUTCOME MEASURES

Transmittance percentage and 10% transmittance cutoff wavelength.

RESULTS

All studied IOLs offered good ultraviolet radiation protection in the ultraviolet C (200-280 nm) and ultraviolet B (280-315 nm) ranges. A number of silicone, PMMA, and acrylic lenses showed different and, at times, only low degrees of absorption in the ultraviolet A (315-400 nm) range.

CONCLUSIONS

Intraocular lenses of different compositions have ultraviolet radiation absorption characteristics different from that of the crystalline lens.

Glare disability in patients with hydrophilic and hydrophobic acrylic intraocular lens implants

PURPOSE

To compare glare disability test results in patients with hydrophilic and hydrophobic acrylic intraocular lenses (IOL).

METHODS

Sixty eyes of 60 patients were studied in three groups of 20. Each eye in Group 1 had a single-piece hydrophilic acrylic (Bioacryl, Biotech, France) IOL implant, and each eye in Group 2 had a three-piece hydrophobic acrylic (AcrySof, Alcon, USA) IOL implant. Group 3 was the control group, and consisted of eyes without cataracts. Glare disability was tested using the Ophthimus glare sensitivity test (Ophthimus, Sweden). For each eye, we determined log contrast sensitivity values without exposure to glare source and with exposure to glare source. The difference between these values was recorded as the threshold contrast increase. An infrared camera was used to measure pupil diameter during glare disability testing, and pupil diameter greater than 4 mm was used as an exclusion criterion to eliminate edge design as a potential contributor to glare disability.

RESULTS

The respective mean log contrast sensitivity scores for Groups 1, 2, and 3 in the absence of the glare source were 0.80 +/- 0.03, 0.81 +/- 0.04, and 0.79 +/- 0.08. The corresponding findings with glare source were 0.84 +/- 0.07, 0.89 +/- 0.07, and 0.84 +/- 0.03. The threshold contrast increase in Group 2 (0.070 +/- 0.035) was significantly higher than that in both Group 1 (0.043 +/- 0.040) and the control group (0.045 +/- 0.026) (p < 0.05 for both comparisons). There were no significant differences between Group 1 and the control group regarding log contrast sensitivity values with glare source and threshold contrast increase (p > 0.05 for both comparisons).

CONCLUSIONS

The eyes with hydrophilic acrylic IOL showed better glare disability results than those with hydrophobic acrylic IOL. The superior performance of the hydrophilic acrylic IOL could be related to their lower refractive index and equi-convex design.