Cataract Surgery in the Glaucoma Patient
Table 1: Mean Intraocular Pressure Reductions of Phacotrabeculectomy versus Non-bleb Surgeries n Treatment
60 Phacotrabectomomy Jin et al.8 17 Phaco/IOL
25 Phaco/IOL iStent 48 Canaloplasty 54 Phaco/IOL
Canaloplasty
35 Trabectome 10 Phaco/IOL Trabectome
Minckler et al.13 Ferrari et al.14
IOL = intraocular lens; PO = post-operative.
Table 2: Characteristics and Intraocular Pressure Results of Non-glaucomatous Eye when Operated with Phaco/Intraocular Lens
Group Eyes (n) Age (Years) Post-operation FU (Years)
31–23 19 22–20 62 19–18 86 17–15 223 14–9
198 69
70.9 67.4 71.2 70.5
p-value — 0.57 All eyes 588
70.3
2.4 4.6 4.9 4.7 4.2
0.002 4.5
Sorted according to their pre-surgical intraocular pressure (IOP) group.16
17.8 15.8 15.5 14.6 13.1
Mean IOP (mmHg)
At surgery 1 year Post-operation Change at 1 Year Final 24.5 20.9 18.3 15.9 12.7
-6.7 -5.1 -2.8 -1.4 +0.4
<0.001 16.0
FU = follow-up.
occurs, the fistula’s lumen and bleb fails. Repeated needlings of the bleb sometimes salvage the outflow channel. If needling is unsuccessful, elevated IOP recurs, and the operation fails. Application of mitomycin C to the sclera decreases scarring and allows more fistulas and blebs to survive. However, in the short term, this treatment can retard healing too much causing hypotony, choroidal effusion, and macular edema. Long term, bleb rupture with hypotony, and sometimes endophthalmitis, can occur years later. The National Survey of Trabeculectomy III4
reported that
of 1,240 eyes following trabeculectomy, 46% had early complications and 42% had late complications.
Unsolved problems of trabeculectomy include acceleration of cataract formation and prolonged time until vision and IOP stabilize (i.e. six to 12 post-operative visits over two to four months). Continuous attention to aqueous flow during this time sometimes requires cutting flap sutures and bleb needlings. This effort makes post-operative follow-up tedious for both patients and surgeons.
In 1997, the ExPRESS X shunt5 was introduced to better control aqueous
flow. Its purpose is to create a scleral opening whose lumen is uniform size, i.e. 50µm, and does not change over time.6
A 2.42mm stainless steel
tube is inserted through a scleral opening made with a sapphire blade (Optonol), or a 25-gauge needle, and its back plate rests under a scleral flap; the same as a flap that is made for traditional trabeculectomy. This steel shunt decreases the short-term problems of irregular aqueous flow: hypotony, or bleb failure. However, longer-term bleb problems such as bleb failure resulting in elevated IOP and bleb rupture leading to hypotony or endophthalmitis still occur, although less frequently.
US OPHTHALMIC REVIEW
Impact of Phacoemulsification/Lens Implantation on Co-existent Cataract and Glaucoma In 1975 Charles Kelman7
<0.001 14.5
<0.001 -1.5
18.0 16.1 15.8 14.3 12.9
<0.001 14.4
Final Change (%) -6.5 (27) -4.8 (22) -2.5 (14) -1.6 (10) +0.2 (0) <0.001
-1.6 (10)
3.0 3.0
2.9 2.4
1.0 0.8
25.7 25.0
16.1 15.2
-9.6 -9.8
16.4 15.3
-9.3 -9.7
Poley et al.9
Spiegel et al.10 Lewis et al.11
Shingleton et al.12
Authors of Study PO Year Average Glaucoma Drops Before 1.6 1.3 1.5 1.9 1.5
3.0 4.5 1.0 1.0 1.0
After 0.2 1.0 0.5 0.6 0.2
14.5 18.7 15.8 15.3 13.7
-8.6 -6.0 -5.7 -8.6
Intraocular Pressure
Before surgery At 1 year 1-year Change At Final Final Change 23.1 24.7 21.5 23.9 24.4
-10.7
14.9 16.3 15.8 15.3 13.7
-8.2 -8.4 -5.7 -8.6
-10.7
introduced phacoemulsification (phaco) for
cataract removal. Today, this technique, together with artificial lens implantation, is the preferred technique for treating cataract. Since this technique leaves the lens capsule intact to separate vitreous from aqueous, and a clear corneal phaco incision now spares the conjunctiva for later filtering glaucoma surgery if needed, control of glaucoma with trabeculectomy is no longer necessary before cataract surgery with phaco/intraocular lens implantation (IOL). This new rationale led to the development of the combined procedure.
Combined Procedures
Cataract and glaucoma operations are now successively combined into one procedure, and are described as a combined procedure.8
A
combined procedure is a trabeculectomy, with or without an ExPRESS™ shunt, combined with phaco/lens implantation into one procedure. Another term for a combined procedure is phacotrabeculectomy. Patients are no longer required to endure two months of visual disability while the glaucoma operation heals before the cataract can be removed, since the two operations can be accomplished with one surgical procedure.
Non-bleb Glaucoma Surgery
Methods for non-bleb glaucoma surgery have been developed to decrease problems associated with phacotrabeculectomy, which entails a functioning conjunctival bleb. Table 1 compares IOP reductions of non-bleb procedures with those of phaco-trabeculectomy.
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