Maximizing the Use of the Crystalens HD In a Variety of Cases

Understand how this top surgeon managed patients preoperatively and postoperatively for optimal outcomes.

By John F. Doane, MD, FACS

The introduction of the Crystalens HD has had a tremendous impact on my refractive and cataract surgery practice. This accommodating IOL provides distance, intermediate and near visual acuity in a single eye. In a bilateral implantation, the synergistic effects are greater than the individual parts, giving credence to the adage "two eyes are better than one."

Simply implanting the Crystalens HD in and of itself is a new process, because it's a flexible hapticplate- optic platform. Aside from implanting the lens, the more important task involves understanding what patients want and expect from their surgery and managing key issues postoperatively.

With 10 years of experience implanting the Crystalens, I've learned many things about patient management. For example, a physician has to have the wherewithal to know he may have to employ a different surgical technique in each eye. Specifically, limbal relaxing incisions (LRIs) may be required in 30% of cases, and small laser vision correction adjustments of 0.50D of spherical equivalent may be needed in 20% to 25% of eyes to achieve patient satisfaction. With perseverance, surgeons can achieve this.

The following case studies demonstrate the diverse applications for the Crystalens HD in a 21st Century cataract and refractive surgery practice.

Case 1

A 72-year-old man presented with a 3-year history of decreasing distance and night vision. He had an approximate 10-year history of type 2 diabetes and was being treated for arthritis and hypertension. He had previously corrected to 20/15 in each eye separately but we tested him with bestspectacle correction at 20/25 minus in each eye.

His preoperative manifest refraction was −2.25 +0.5 x 045 OD and −3.0 +0.5 x 050 OS. Manual keratometry was OD 44.25 x 000 / 44.75 x 090, and OS 44.12 x 177 / 45.25 x 087. Pachymetry was 550 microns OD and 561 microns OS. IOL Master axial lengths were 25.73 OD and 26.15 OS. His scotopic pupil size was 6.1 mm OD and 6.3 mm OS.

Meeting Expectations

The patient led an active lifestyle. He wanted spectacle independence but no induced scotopic symptoms, so we implanted the Crystalens HD bilaterally during cataract surgery. Because I usually induce about 0.50D of corneal astigmatism 90° from my temporal incision, I decided to place a 5-mm LRI with a 600-micron blade setting at 270° OD and a 5-mm LRI with a 600-micron blade setting at 087° and 267°.

The target for the first eye (left) was −0.75D. The patient had a relatively long eye, normal K values but low myopia. The longer end-to-end length HD-520 lens was available, but I selected a 12.5D Crystalens HD-520 IOL, because the unadulterated Holladay 2 formula within the Holladay IOL Consultant predicted a −0.65 refraction. At 4 days post-op, his uncorrected distance vision was 20/20-1 and J-6 at near. The right eye underwent surgery 4 days after the left eye. I targeted −0.50D and selected a Crystalens HD-520 13.5D lens that predicted a −0.57 refraction with an unadulterated Holladay 2 formula.

Post-op Care

After surgery, I routinely prescribe prednisolone acetate (Pred Forte, Allergan Inc.) q.i.d. and taper it by day 28. I prescribe ketorolac (Acular, Allergan Inc.) q.i.d. for 28 days as well as gatifloxacin (Zymar, Allergan Inc.) q.i.d. for one week. At 5 months post-op, the patient's uncorrected distance vision is 20/25+2 OD, 20/25 OS and 20/20 OU. His uncorrected near vision at 14 inches is J-3 OD, J-3 OS and J-1 OU. His manifest refraction was −0.75 + 0.5 x 118 for 20/20 OD and −0.25 sphere for 20/20 OS and 20/20 OU. At 4 months post-op, he reported difficulty reading. I suggested he put a lamp by his favorite chair in which he reads, and this resolved the issue. Now, he's reading comfortably with no correction.

Case 2

I evaluated a 51-year-old sales executive who complained about being "burned out" when it came to wearing contact lenses and eyeglasses. His refraction was −2.25 −1.5 x 170 for 20/20 OD and −3.0 +0.5 x 005 for 20/20+ OS. His uncorrected near vision without distance correction was J-2 OD and J-3 OS. His distance corrected near vision without add was J-10 and J-5. His spectacle-corrected distance vision OS was undercorrected by −0.75D so he could function without a bifocal, which was his preference. He didn't want full monovision, and wasn't sure he wanted a target of −1.5 sphere in his nondominant eye. Because of the patient's expectations, the only solution I could offer was a presbyopia-correcting IOL.

Before surgery, I explained that he'd lose the excellent near vision he had with his contact lenses and eyeglasses if I targeted him for plano at distance. He understood this, but his priority was to improve his uncorrected distance vision. His manual keratometry was 41.5 sphere OD and 42.00 x 000 / 41.50 x 095 OS. His pachymetry was 520 OD and 530 OS. His axial lengths were 25.57 mm OD and 25.63 mm OS. His scotopic pupil size was 6.5 mm OD and 6.8 mm OS. Interestingly, he had flatter than average K readings and longer than average axial lengths. The patient was approximately 6 feet, 5 inches tall, so these measurements gave him an advantage for reading because of his long arms, as you'll see below.

IOL Selection

I selected a 17.0D HD-500 lens for the patient's left eye. I targeted −0.5 sphere in the left eye and predicted a −0.03 refraction with the unadulterated Holladay 2 formula within the Holladay IOL Consultant. At 1 week, the refraction was −1.0 +0.5 x 128 for 20/20+2, and his uncorrected near vision was J-5 at 24 inches. For the right eye, I selected a 17.0D HD-500 lens that predicted +0.33D postoperatively. At 1 week post-op, the patient's uncorrected distance vision was 20/20 OD; the uncorrected near vision was J-1 at 24 inches and the refraction was −0.25 +0.5 x 013 for 20/15-1 acuity. At 4 months post-op, the patient reported he was doing well. His uncorrected distance vision was 20/20-2 OD, 20/25-1 OS and 20/20 OU. His uncorrected near vision was J-3 in each eye and J-1 OU. He reported his near, intermediate and distance vision was good. The length of his arms allows him to read 20 inches out for near vision, but he requires no correction.

Case 3

A 49-year-old woman who was employed as a claims adjuster complained of decreased distance and near vision. Her ocular history included 16-cut RK OD and 12-cut RK OS in 1993. Her fogged manifest refraction was +1.75 +1.0 x 170 OD for 20/20-1 and +3.75 +0.5 x 130 for 20/25 OS. As with all RK cases, I perform an early morning (8 am), midday (noon) and late afternoon (after 4 pm) refraction to determine diurnal variation. The patient had no significant refractive change (> 0.75D spherical equivalent between most minus and most plus refractions). Two options were presented to her: a multifocal rigid contact lens or bilateral accommodative IOLs in a refractive lens replacement procedure. Her manual K readings were 37.12 x 005 / 39.00 x 095 OD and 36.75 x 042 / 36.37 x 132 OS. Her central pachymetries were 632 OD and 631 OS. The patient had normal bilateral endothelium. Her axial lengths were 24.55 mm OD and 24.62 mm OS. Her scotopic pupil sizes were 6.1 mm OD and 6.2 mm OS.

Calculating IOL Power

Based on the average central 2-mm optical zone K reading from the Humphrey Atlas topographer, I selected a K-true value. I subtract 1.0D from this value and insert this as the K-true reading for the IOL calculation. In this patient's case, the value for the left eye was 34.0D; the value for the right eye was 35.8D. The adjusted K-true value was 33.0D OS and 34.8D OD. For the left eye, I selected a 30.0D HD-500 lens. The unadulterated Holladay 2 formula predicted a −0.75 refractive error. Important note: If eight or more incisions are required, generally I'll choose a scleral tunnel wound construction to avoid rupturing the radial incisions. For six or fewer incisions, I'll choose a clear cornea technique.

Post-op Results

At 1 week post-op, the refraction was +1.5 sphere for 20/25+1 acuity OS. This was an excellent 1-week refractive end point. At 1 week, the cornea was artificially flat due to corneal edema. As the edema decreases, the cornea assumes its presurgical corneal value. At 1 to 2 months post-op, the eye stabilizes and presents the end refraction.

Keep in mind that if the patient is plano or minus at 1 day and 1 week post-op, you can expect progressively more minus to occur at 1 month and possibly 2 months after surgery. In a longer eye, my experience with the HD-500 is that I'll possibly get more minus than predicted by the unadulterated Holladay 2 IOL formula. In cases such as this, I'd prefer to be plano or slightly 1.0D to 2.0D hyperopic postoperatively, because these cases are much easier to get to plano with a hyperopic corneal laser vision correction than a flattening or myopic procedure. These corneas already are significantly flat and may not get any flatter with a myopic excimer laser ablation procedure.

For the patient's right eye, I selected a 29.0D HD-500 lens that predicted a −1.09 refractive error based on the unadulterated Holladay 2 formula. At 1 day post-op, the refraction OD was +1.50 +0.5 x 047 for 20/30+2. The uncorrected visual acuity was 20/30-2 OD, 20/30 OS and 20/25 OU. The uncorrected near was J-2+ OD, J-3+ OS and J-1 OU. The manifest refraction was −0.5 +0.75 x 043 for 20/25 OD and −0.5 +1.25 x 005 for 20/25 OS.

Interestingly, the near visual acuity with best distance correction was J-1 OD, J-2 OS and J-1 OU. The patient's average 2-mm optical zone average K value had returned to its pre-op reading, so I'm fairly certain there will be no significant change in the end result. It's possible the patient has completed treatment. In my experience, a patient who had previous radial keratotomy will require additional laser vision correction about 35% to 40% of the time to reach a refractive end point that allows spectacle independence. OM