Remember when we referred for cataracts surgery when the vision is significantly subjectively affected by lens opacification (in other words, “Ripe”)? They met the magic limit of 20/40. No glare testing, no densitometry were used to qualify, and we used brightness acuity testers and potential acuity meters to demonstrate possible improvement in the acuity. We used manual keratometers and contact ultrasound A-scans for IOL measurement.
Now, we use glare testing to prove the cataract is the cause of the complaint. We do topography, possibly more than once, to obtain keratometry values, which may be refractive or simulated keratometry. We use noncontact A-Scan devices for IOL measurement, and perform aberrometry intraoperatively to reassess the math. Cataract surgery is now a refractive procedure with James Bond toys. Cataract procedures are no longer reserved for just cataracts. Several indications exist for referral for phacoemulsification.
One reason to refer is severe anisometropia resulting from a myopic shift. Cataract formation, particularly nuclear sclerosis, may change the index of refraction, causing a myopic shift. The refractive error may become significantly different if this change is asymmetrical. If it happens quickly, over 6-months for example, remaking the glasses become expensive and they may not be visually comfortable. Sending the case history with detailed information on the change in refraction to your preferred cataract surgeon for a phacoemulsification consult.
Another reason to refer is treatment for narrow-angle glaucoma. Removal of the crystalline lens directly addresses narrow-angle glaucoma by creating more room in the angle. Significant drop in intraocular pressure following phaco in cases of narrow angles have been reported. Phacoemulsification with intraocular lens implantation was compared to laser peripheral iridotomy as treatment for acute primary angle closure by Husain, et al. Less complications were reported in the phaco treatment group, and this group had a lower rate of defined IOP elevation at 2 years compared with the LPI group. However, the reduction in IOP was not found in all studies of narrow angles and phacoemulsification.
Intraocular pressure reduction following cataract surgery may occur in cases of primary open angle glaucoma as well. Mayer, et al studied predictive factors for IOP reduction following phacoemulsification, and found that at 12 months, pre-operative IOP and number of anti-glaucoma medications remained correlated with total IOP reduction following surgery. However, at 12 months, the IOP of the narrow-angle glaucoma and POAG groups were not significantly different.
Bilak, et al studied biometric parameters including axial length, anterior chamber depth and lens thickness relative to IOP. They reported decreased axial length and IOP with increased anterior chamber depth one month after cataract surgery. They suggested the best parameter for estimation of postoperative IOP reduction was preoperative IOP. Patients with higher IOP tend to do enjoy the largest decrease in IOP following phaco. Patients with higher IOPs would then be better candidates for cataract surgery and hopeful intraocular pressure reduction.
Medical necessity, such as limitation of mobility by vision reduction and loss of visualization of the retina in cases of glaucoma or retinopathy, would be a reason for cataract surgery. While inactive patients may feel their 20/50 vision is not hindering their sedentary lifestyle, if they cannot see curbs well and are at risk of falling, cataract surgery may be beneficial. Cataractous reduction in contrast sensitivity increases the risk of a fall and affects stability.
Cataract surgery has been reported to improve postural stability and decrease risk of falling. If the patient’s retinal specialist needs to assess their retina for diabetic changes, they may refer for phaco directly with a cataract surgeon so communication about phaco with all the patient’s doctors is important.
Dysfunctional Lens Syndrome (DLS) is a new term in the ophthalmic arena, but one that is growing in popularity as a reason to perform cataract surgery. DLS is typically used to describe patients who complain about their visual quality due to early changes in the lens.
A common example used by more progressive anterior segment surgeons is patients who underwent LASIK for distance and present to your office reporting their surgery “wore off”. While their lens changes may not warrant cataract surgery under current insurance guidelines, lens changes are causing a reduction in visual satisfaction.
They present to your office complaining of their vision being reduced, yet see 20/20, and no spectacle or contact lens correction is going to make them happy. LASIK enhancement is not advisable. Progressive surgeons will consider a refractive lens extraction in these case then may have ten years ago. This option is, of course, not covered by insurance. Low risk of complications with phacoemulsification combined with improved visual outcomes make this option more popular amongst those with the financial means.
Pursuing this option may require more patient education as well as more communication with your co-managing surgeon. Improvement in quality of life for these patients is worth the effort.