26 Lens Management
26.1 Phaco-Vitrectomy
26.2 Pars Plana Lensectomy
26.3 Intraocular Lens Explantation
26.4 Secondary Intraocular Lens Insertion Clinical Scenarios & Clinical Decision Making
26.5 Sulcus Intraocular Lens
26.6 Anterior Chamber Intraocular Lens
26.7 Iris Fixated Intraocular Lenses
26.8.1 Scleral Sutured Intraocular Lens – Traditional 2 Point Fixation
26.8.2 Scleral Sutured Posterior Chamber Intraocular Lens 4 Point Fixation
26.8.3 Scleral Sutured Posterior Chamber Intraocular Lens – “Hoffman” Corneoscleral Pockets
26.8.4 Alternate Technique to Rescue a Dislocated IOL – Triangular Scleral Flap, Sutured IOL Technique
26.8.5 Suturing Without Exchanging the Intraocular Lens
26.9 Sutureless Scleral Fixation of an Intraocular Lens
26.1 Phaco-Vitrectomy
Phacovitrectomy may be useful in the following scenarios:
- Cataract impairs visualization of the fundus such that surgical goals cannot be achieved (e.g. poor view for macular membrane peeling)
- Removal of a cataract at the same time as removal of silicone oil tamponade following retinal detachment repair
- Crystalline lens inhibits the ability to perform peripheral work such as vitreous base shaving in rhegmatogenous retinal detachment, or access to anterior loop proliferation
- The patient is a poor surgical candidate for medical reasons, and concurrent phacoemulsification is used as a means of minimizing multiple operations.
- A diabetic non-clearing vitreous hemorrhage - concurrent phacoemulsification may allow for faster clearance of residual post-operative “shake-out” vitreous hemorrhage and also permits removal of the anterior retrolenticular vitreous hemorrhage
- As a surrogate for pars plana vitrectomy with pars plana lensectomy in cases in which migration of lens fragments posteriorly is costly
Advantages include faster visual rehabilitation, easier access for vitreous base shaving, and the potential for better visualization. Potential disadvantages include difficulties in performing accurate pre-operative lens calculations, increased post-operative inflammation, longer operative time, suboptimal refractive outcomes (typically myopic shifts, hyperopic if not using an endotamponade), corneal edema precluding operative visualization, post-operative hypotony, higher rates of post-operative endophthalmitis, and the risk for lens dislocation and/or malposition with use of a tamponade.
In general it is easiest to remove the cataract prior to performing the vitrectomy. This allows for the clearest visualization of the fundus. However, some surgeons do prefer to remove silicone oil prior to performing phacoemulsification since the oil can increase posterior pressure on the crystalline lens, making phacoemulsification more difficult.
Valved trocars can be placed prior to beginning the phacoemulsification procedure to allow for easier trocar insertion prior to clear corneal incision. The infusion in the pars plana may be visualized but should not be turned on until completion of the phacoemulsification procedure.
Key Considerations:
- Wound construction – Consider fashioning a posterior limbo-corneal tunnel and avoid excessive intra-corneal tunnel length, which may lead to corneal hydration and poor view during vitrectomy
- Capsulorhexis – should be approximately 5-5.5mm in diameter to avoid decentration of the intraocular lens after placement of a tamponade. If using trypan blue, note that it may migrate around the zonules and stain the vitreous gel
- Nuclear disassembly – consider using the technique that is safest, fastest, and most efficient in your hands. Avoid excessive manipulation within the bag to allow for stable placement of an intraocular lens. Phacodynamics with vitrectomy machines tend to be more prone to post-occlusion surge than dedicated phacoemulsification machines. Avoid excessive movement in and out of the eye with irrigating instruments to avoid corneal hydration
- Intra-ocular lens (IOL) choice – Consider a three-piece IOL, which are generally larger than single-piece IOLs. They tend to be more stable, especially when an intravitreal tamponade is required and when there is the potential for capsular phimosis and contraction post-operatively. A hydrophobic lens is preferred, as hydrophilic IOLs are more prone to opacification when vitrectomy is performed with a gas tamponade.
- IOL insertion –In cases of unstable lens position after placement of a tamponade, consider leaving a small amount of viscoelastic in the anterior chamber or adding acetylcholine chloride (Miochol™-E) to keep the IOL in the capsular bag
- Wound closure – minimally irrigate the paracenteses and the main wound to avoid impairing view to the fundus. If suturing, consider placing the 10-0 nylon while cohesive viscoelastic is still in the anterior chamber to ease passing the suture in a formed chamber, then waiting to tie it until the viscoelastic has been removed with the irrigation / aspiration hand piece
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Westmead Eye Manual
This invaluable open-source textbook for eye care professionals summarises the steps ophthalmologists need to perform when examining a patient.
