Implant lenses

A 0.1% ophthalmic preparation is recommended for prevention of postoperative ophthalmic inflammation and can be used after intraocular lens implantation and strabismus surgery. A topical gel containing 3% diclofenac is effective for solar keratoses. Diclofenac in rectal suppository form can be considered for preemptive analgesia and postoperative nausea. In Europe, diclofenac is also available as an oral mouthwash and for intramuscular administration. 

Tetracaine, an ester of para-aminobenzoic acid (PABA), has been widely used for topical anesthesia of the eye. It is currently available in a 0.5% solution. Its onset, intensity, and duration of anesthesia are comparable with those of proparacaine and benoxinate (Figure 6-2). Onset of anesthesia sufficient to permit tonometry or other minor procedures involving the superficial cornea and conjimc-tiva is 10 to 20 seconds, and duration of anesthesia is 10 to 20 minutes. It has been reported, however, that the 1% solution produces anesthesia lasting nearly an hour. Tetracaine 1% has also been used successfully to provide anesthesia during phacoemulsification cataract surgery and intraocular lens implantation. 

Intraocular dapiprazole has been shown to be clim-cally effective for reversing mydriasis during extracapsn-lar cataract extraction with lOL implantation. A stndy compared intraocnlar dapiprazole 0.25% with acetylcholine 1% and fitimd that after extracapsular cataract extraction with posterior chamber intraocmar lens implantation, 0.25% dapiprazole was effective in prodnc-ing a more persistent miosis without side effects. The drug also reduced the transient postoperative lOP increase. 

Ponte F, C.illino S, Faranda F, et al. Intraocular dapiprazole for the reversal of mydriasis after cataract extraction with intraocular lens implantation. J Cataract Refract Surg 1991 17 785-789. 

Hyaluronic acid is considered to have low inflammatory and antigenic potential, and has been used in various intraocular procedures. In addition to filtration bleb formation, it has been used to protect the corneal endothelium during intraocular lens implantation and keratoplasty, to reform the anterior chamber, to push back a bulging vitreous face, and in retinal detachment surgery as a vitreous replacement. 

A 63-year-old woman underwent phacoemulsification and lens implantation under sub-tenon block. After the local anesthetic was injected, the eye was prepared with an aqueous solution of povidone iodine and the surgery proceeded uneventfully. At the end, gentamicin and betamethasone were injected subconjunctivally. Over the next few days she developed orbital cellulitis, requiring intravenous antibiotics. 

A subsequent Phase II, multicenter, randomized, double-masked, placebo-controlled clinical trial was performed in patients undergoing phacoemulsification and intraocular lens implantation (18). Only one eye per patient was eligible for treatment and exclusion criteria included previous uveitis, concurrent anterior segment disease or intraoperative surgical complications. Patients were randomized in a 2 1 ratio into an active treatment group or a control group. Patients in the two... 

Saika et al. (79) reported on a group of 19 eyes that had pars plana vitrectomy, elevation of the posterior hyaloid, fluid gas exchange, and cataract extraction with intraocular lens implant. Ten of the 19 eyes had decreased in macular edema as identified on optical coherence tomography the mean thickness decreased from 383 to 208 pm. However, there was no statistically significant improvement in visual acuity. If only patients with more recent onset of branch retinal vein occlusion were included in the analysis, a visual improvement was noted. 

The lens of the eye sometimes becomes opaque (cataract formation), apparently due to cross-linking of its proteinaceous material, and must be removed to restore vision. Intraocular lens implants are normally made from poly(methyl methacrylate), although other materials. Including hydrogels, have been tried. In over 73% of the cases, vision of 20/40 or better can be achieved by these implants (67). The cornea is also subject to cataract formation and... 

Topical heparin eyedrops were effective for long-term reduction of fibrotic posterior capsule opacification after extracapsular cataract extraction with intraocular lens implantation (93). Implantation of a heparin drug delivery system into the posterior chamber of experimental animals maintained a significantly higher heparin level in the aqueous humor for a long period of time, suggesting the potential for effective prevention of posterior capsular opacification after phacoemulsification of the lens with no toxic or side effects (94). 

Ravalico G, Tognetto D, Baccara F. Heparin-surface-modified intraocular lens implantation in eyes with pseudoexfoliation syndrome. J Cataract Refract Surg 1994 20 543-549. 

Balazs EA, Miller D, Stegmann R. Viscosurgery and the use of Na-hyaluro-nate in intraocular lens implantation. In International Congress and First Film Festival on Intraocular Implantation, Cannes, France, 1979 l-6. 

Arshinoff SA, Khoury E. HsS versns a balanced salt solution as a corneal wetting agent during rontine cataract extraction and lens implantation. J Cataract Refract Surg 1997 23 1221-1225. 

Shirley, H.L. Chang, M.D. Gerald Lim, M.D. Secondary pigmentary glaucoma associated with piggyback intraocular lens implantation. Case report. J. Cataract Refract. Surg. 2004,30 (10), 2219-2222. 

D.P. DeVore, Long-tmn compatibihty of intraocular lens implant materials, J. Long Term Eff. Med. Implants 1 (1991) 205-216. 

G.D. Kymionis, M.A. Grentzelos, A.E. Karavitaki, P. Zotta, S.H. Yoo, LG. PaUikaris, Combined comeal collagen cross-Unking and posterior chamber tone implantable collamer lens implantation for keratoconus. Ophthalmic Surg. Lasers Imaging 42 (2011) e22-e25. 

In lens implantation, a viscoelastic substance is capable of giving more resistance than air or BSS (balanced salt solution). Furthermore, a viscoelastic offers other helpful properties, such as occupying and maintaining space and protecting the corneal endothelium. In the implantation of foldable lenses, the following rheologic characteristics are worth observing ... 

Following the polishing of the capsule, viscoelastic is injected to unfold and extend the capsular bag (Fig. 68) thereby occupying space to facilitate intraocular lens implantation. 

Following lens implantation, a thorough removal of viscoelastic is advised (Fig. 69, also compare Chapter 8, Aspiration of Viscoelastic). 

Alpar JJ, Alpar AJ, Baca J, Chapman D. Comparison of Healon and Viscoat in cataract extraction and intraocular lens implantation. Ophthalmic Surg 1988 19 636-642... 

Aron-Rosa D, Cohn HC, Aron J-J, Boquety C. Methylcellulose instead of Healon in extracapsular surgery with intraocular lens implantation. Ophthalmology 1983 90 1235-1238... 

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