Biomedical subjects

David J Apple

Publications and source records attributed to David J Apple.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Silicone plate-haptic posterior chamber intraocular lens implanted in the anterior chamber: report of a bilateral case and potential complications.

BACKGROUND AND OBJECTIVE: To evaluate possible complications associated with implantation of a posterior chamber (PC) intraocular lens (IOL) in the anterior chamber. MATERIALS AND METHODS: We analyzed a plate-haptic silicone IOL that had been explanted from the anterior chamber of an 83-year-old female. Additionally, the lens was experimentally reimplanted into the anterior chambers of 3 human cadaver eyes. After fixation of the eyes (Karnovsky's solution), the anterior-posterior length, the white-to-white diameter, the angle-to-angle diameter, and the sulcus-to-sulcus diameter were measured. Two different techniques to cut the eyes were used: sagittal section and corneal buttonhole technique. The plate-haptic silicone lens was then implanted in the anterior chamber and sulcus ciliaris of the eyes. A Kelman multiflex IOL was used as a control for anterior chamber implantation. RESULTS: This experiment demonstrated that the plate-haptic silicone IOL lens is too small and thick for implantation in the anterior chamber and in the sulcus. The lens could easily rotate in the anterior chamber and also dislocate inferiorly, obstructing the visual axis by its edge. The thickness of the lens theoretically could also cause endothelial cell damage and mechanical iris irritation resulting in chronic uveal inflammation. CONCLUSION: This case and experiment should help surgeons realize the risk and potential for IOL-missizing complications that may be caused if a lens design for the capsular bag is implanted in the anterior chamber, especially if a plate-haptic PC-IOL design is used.

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PubMedDate not supplied

Opacification of two hydrophilic acrylic intraocular lenses 3 months after implantation.

BACKGROUND AND OBJECTIVE: To report clinical, pathologic, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from two patients who had early visual disturbances caused by postoperative opacification of the lens optic. MATERIALS AND METHODS: Two hydrophilic IOLs were explanted from patients with decreased visual acuity. The patients became symptomatic 3 months after uneventful phacoemulsification and lens implantation. IOL optic opacification was associated with a fine granularity within the substance of the lens optic. The IOLs were examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red (a special stain for calcium). Some sections were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: Microscopic analyses revealed the presence of multiple fine, granular deposits of variable sizes within the optics of the lenses distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optics' surface. Extension of the opacification into the haptics of the IOLs could also be observed. The deposits stained positive with alizarin red. Energy dispersive x-ray spectroscopy of the internal substance of the IOLs also demonstrated the presence of calcium within the deposits. CONCLUSIONS: This is the first clinicopathologic report of optic and haptic opacification occurring with this hydrophilic acrylic IOL model only 3 months postoperatively. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.

Acrylic Resins↗

PubMedDate not supplied

"Special" intraocular lens designs: why do they sometimes fail?

A variety of new "special" intraocular lens models to optimize the visual performance after cataract surgery have been introduced. The majority of these new intraocular lens designs require a good centration within the capsular bag and/or capsular elasticity. Today, the main post-operative complications after cataract surgery still arise from retained lens epithelial cells within the capsular bag, resulting mainly in anterior and posterior capsule opacification. Some special intraocular lenses are not designed to be effective against proliferating lens epithelial cells. Although lens epithelial cells can never be completely removed from the capsular bag, surgical quality is a major factor for success or failure of these intraocular lens designs.

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