| Main text |
Glaucoma and cataract are the main causes of blindness in the world, glaucoma is in second place as a cause of irreversible blindness in developed countries. The prevalence of glaucoma and cataracts has been increasing with the aging of the population and will continue to do so.
Glaucoma is a defined multifactorial pathology with progressive damage to the optic nerve. According to its cause, it can be classified as primary or secondary glaucoma and according to the appearance of the anterior chamber as open-angle or closed-angle glaucoma.
Glaucoma and cataracts often coexist. It is complicated for the ophthalmologist to treat both pathologies. Glaucoma surgery is a risk factor for cataracts, and cataract surgery affects filtering bleb function. Although cataract surgery in patients with glaucoma may be associated with lowering IOP, it can be technically complicated, especially in patients with angle-closure glaucoma who typically have a shallow anterior chamber and short axial length.
Glaucoma treatment currently consists of reducing IOP, through medication, laser treatment or surgery. For open-angle glaucoma, medication is the first option, and it can be combined or replaced by laser treatment. If the medication fails to control the IOP, filtration surgery is performed. In patients with closed-angle glaucoma, this involves opening the anterior chamber angle. In the present study we evaluated the role of lens extraction and laser peripheral iridotomy to treat glaucoma.
The IOP-lowering effect of cataract surgery is mild in patients with open-angle glaucoma. The results published in the literature regarding IOP reduction are variable. However, everyone agrees that cataract surgery achieves a certain reduction in IOP and can be taken into account as a single procedure in patients with controlled pathology and without a significant visual field defect.
Some studies have indicated that the strongest predictor for a significant IOP reduction is an elevated preoperative IOP. Likewise, the duration of phacoemulsification and the anterior position of the lens may be associated with greater IOP reduction.
Cataract surgery in cases of pseudoexfoliative glaucoma usually has the effect of temporarily reducing IOP and reducing the need for medication. Phacoemulsification has also been recommended as an intervention to prevent the development and progression of glaucoma. However, the IOP-lowering effect in these cases is not long-lasting.
Peripheral laser iridotomy has been used as the main treatment for angle-closure glaucoma. In patients with cataracts and angle closure at the same time, lens extraction is effective and is associated with a significant reduction in IOP. Regarding acute angle closure, some studies have recommended lens extraction before peripheral laser iridotomy.
There is no evidence to support clear lensectomy in patients with open-angle glaucoma. In patients with angle-closure glaucoma, trabeculectomy is probably more effective than clear lensectomy in controlling IOP, but with more complications.
The EAGLE study compared 419 newly diagnosed participants with angle closure and IOP greater than 30 mmHg. or primary closed-angle glaucoma, undergoing clear lensectomy or peripheral laser iridotomy. Although the difference in IOP at three years was slightly in favor of clear lensectomy, there was a considerable reduction in the need for continued antiglaucoma medication or surgery and better quality of life after lensectomy. In addition, it is a less expensive procedure for health services.
Peripheral laser iridotomy is the first treatment for angle closure. Although iridotomy is considered a safe procedure, some studies have reported an increased risk of cataract progression in patients with angle closure undergoing peripheral laser iridotomy, especially women and elderly patients with a history of diabetes.
Potential complications are: endothelial cell damage, IOP spikes, anterior uveitis, pigment dispersion, hyphema, and other posterior segment complications. It is difficult to quantify the effectiveness of iridotomy in patients with primary angle-closure glaucoma. The presence of peripheral anterior synechiae and persistence of iridotrabecular contact are the main risks of not being able to control IOP. However, peripheral laser iridotomy is proven effective in preventing acute angle closure in the paired eye.
Laser iridotomy, on the other hand, is not effective in patients with primary open-angle glaucoma, nor have clinical benefits been found in patients with pigmentary glaucoma.
| Conclusions |
Cataract surgery has a recognized IOP-lowering effect, especially in eyes with pseudoexfoliative glaucoma and primary angle-closure glaucoma. The reduction in IOP appears to be moderate and reduces over time in open-angle glaucoma, while it is important and long-lasting in primary angle-closure glaucoma.
Cataract surgery is a logical option as the only procedure in eyes with cataracts and mild open-angle glaucoma or ocular hypertension. Clear lensectomy is not justified to treat open-angle glaucoma. Although peripheral laser iridotomy has been used as the first treatment against primary angle-closure glaucoma, clear lensectomy could be used as the first option in these cases.
