How to Succeed with Presbyopic Patients Tips from the Trenches

BY RANDY MCLAUGHLIN, O.D., M.S.
APR. 1997

As if mail-order, managed care and mass marketing weren't enough, we must face yet another challenge as many of our patients enter presbyopia . . . helping them see with their aging eyes.

Why are presbyopic contact lens patients so important to me? I don't sell or dispense spectacles. My practice is limited to comprehensive eye examinations, contact lens prescribing and sports vision analysis. We're all aware of the competitive contact lens marketplace. Mail-order lens replacement, convenient commercial practice locations, managed care limitations and the static contact lens wearing population are only a few of the contributing factors.

Although most of us have modified our practices to deal with these issues, there's one issue many practitioners don't even recognize and innocently ignore -- age. Many previously satisfied contact lens-wearing patients reluctantly discontinue lens wear when presbyopic complaints are not satisfied with contact lenses.

Of course, the simplest solution is for these patients to wear inexpensive reading spectacles over their contact lenses. These 'readers' or 'cheaters,' as patients call them, will provide the best distance and near acuity for under $20.

However, vanity is one of the major reasons patients choose to wear contact lenses. How many times have you heard, "If I'm going to have to wear eyeglasses for reading, I might as well wear them all the time."? Our task is to prescribe a contact lens system that will keep patients satisfied in their lenses by comfortably correcting the distance and near vision.

MONOVISION METHODOLOGY

Monovision is a straightforward presentation, and because we have ready access to trial lenses from the manufacturers, we can trial fit at little or no added cost to the patient. For current contact lens wearers, fitting and materials charges should be comparable to the fees they paid for their previous lenses.

Generally, I prescribe the patient's habitual lenses for monovision, correcting the dominant eye for distance. To determine eye dominance, I ask which hand the patient uses to throw or write. (Usually, a right-handed individual is right eye dominant.) Then to confirm the dominant eye, I ask which eye he or she uses to sight a gun or take a picture.

I also consider the patient's prescription. For a patient with residual astigmatism in one eye, I might trial dispense a lens for near vision on that eye. Finally, I gain patient input about the vision.

A CRESCENT DESIGN TRANSLATING RGP BIFOCAL. USE TRUNCATION AND PRISM BALLASTING TO KEEP THE READING SEGMENT AT ABOUT THE 6 O'CLOCK POSITION.

FINE-TUNING MONOVISION

There's no question, monovision is more successful for early presbyopes (under +1.75D add). For the trial fitting, I usually prescribe the least amount of minus correction to achieve 20/20 in the distance eye and the smallest reading compensation over their current distance prescription in the non-dominant eye. Because of this technique, I believe hyperopic patients adjust to monovision better than myopic patients.

Remind all patients to insert their near lens first and remove it last. Hyperopic presbyopic patients especially appreciate a visibility or cosmetic tint to aid with lens insertion.

REINFORCE PATIENT SATISFACTION

Before monovision patients leave the initial fitting, I ask them to look at their watch. Generally, they report how clearly they see the dial, providing positive reinforcement of their vision correction before they leave my office.

At the one-week exam, based on the patient's response to my questions regarding vision and lifestyle, I'll know if the patient will be satisfied with this modality. At this visit, I may make slight adjustments to the prescription. I've found that patients in professions with a high near demand, such as accountants, jewelers and lawyers, generally don't embrace monovision as well as patients with basically equal distance and near tasks, such as homemakers or teachers.

Most patients will commit to monovision within two weeks. If they enjoy it, prescribe it! If they don't, then it's time to present the advantages and disadvantages of bifocal contact lenses.

CURRENT OPTIONS IN HYDROGELS

Hydrogel materials are the most instantly comfortable, so most presbyopic patients want soft bifocals. Unfortunately, hydrogel materials have two disadvantages for bifocal design when compared to rigid gas permeable lenses. Soft lenses don't transmit light (i.e., images) as sharply as rigid lenses. Furthermore, soft lenses don't move especially well on the cornea, so a translating lens with a near segment has not been achieved.

I use the following simultaneous bifocal soft lenses: Bausch & Lomb's Occasions aspheric lens; Ocular Sciences/American Hydron's Hydron Echelon diffraction grating lens, The LifeStyle Co.'s LifeStyle Xtra aspheric soft bifocal lens; and Sunsoft's Multifocal simultaneous lens. The B&L and LifeStyle lenses are available for frequent replacement, and the Sunsoft lens has a very good guaranteed fitting price. Most companies have guaranteed fit policies to help practitioners fit empirically with keratometry and refraction, or they provide complimentary trial lenses. Some companies do both.

Most soft multifocals are still a compromise of overall vision. Be sure that patients understand that the lenses may not be suitable for all occasions.

SIMULTANEOUS VISION WITH RGP LENSES

I initially tell my patients that rigid gas permeable lenses will provide the maximum vision at distance and near in a bifocal design. Previously adapted RGP wearers are the best candidates for bifocal RGPs.

Of the two RGP bifocal design types -- simultaneous and translating -- simultaneous vision involves a less complex fitting process and is an excellent first choice for early presbyopes. The LifeStyle Co.'s LifeStyle Gp, Conforma's VFL 3, Fused Kontact's aspheric Tangent Streak No Line multifocal, GBF's V/X aspheric multifocal, Unilens' aspheric multifocal and Polymer Technology's investigational aspheric RGP are a few of the more popular simultaneous designs.

All multifocal RGPs involve a lengthy fitting process, which requires more office visits and consequently, higher fitting and material fees. Nationwide, professional fees vary from $400 to $700 (excluding the comprehensive eye exam).

COMBINE EMPIRICAL & TRIAL FITTING FOR OPTIMUM SUCCESS

Fitting simultaneous bifocal RGPs may involve two philosophies -- empirical fitting and trial fitting. The initial bifocal order is rarely the final lens design dispensed, so be sure the lenses you order are warranted by the manufacturer. Most laboratories will support your efforts with guaranteed fit or warranty programs.

EVEN WITH TRUNCATION AND PRISM BALLASTING, A TRANSLATING RGP MAY STILL ROTATE, USUALLY NASALLY. IF THIS IS THE CASE, ALTER THE BASE OF THE PRISM UP TO 30 DEGREES TO COMPENSATE.

For empirical fitting, you must supply the keratometric reading, refraction and reading add required to determine the first order. These lenses will become the first diagnostic lenses for this individual when a trial fitting set is unavailable. Trial fitting has the advantage of screening out individuals who won't be able to tolerate simultaneous vision. Trial lenses worn with appropriate overcorrection in a trial frame will determine approximate quality of vision. If the vision is clearly unacceptable, I won't order lenses. I perform the overrefraction with the phoropter at distance. Then, I place this correction into a trial frame which is worn over the bifocal RGP contact lenses to give the patient the most natural viewing experience.

Before ordering the lenses, I explain my total fee. I emphasize that if I'm unable to finalize an acceptable lens, I'll refund the materials charge, minus sales tax. I make sure this is a positive presentation. I assure patients that I won't order lenses unless I feel they will meet the patient's visual expectations. I let patients know that my office is experienced in fitting this type of contact lens, and will supply references of satisfied patients.

When I order an empirically determined pair of simultaneous bifocal lenses, I require a deposit of the fitting fee at the initial visit. This minimizes the patient's financial burden, relieves any initial apprehension and, hopefully, improves the patient's confidence.

If vision with the initial lenses is acceptable for driving and for the workplace, I ask the patient to evaluate the lenses for one to two weeks. If vision is unacceptable at dispensing, I perform an overrefraction at distance and near and order a second pair of lenses under the bifocal warranty program.

RGP LENSES

Aspheric and other Simultaneous Vision Lenses:

• - Salvatori ACC Bivision, Multisite, ACX-Target
• - ConstaVu
• - PC Optical ACF
• - LifeStyle Co. Lifestyle GP
• - Metro Optics Metro Progressive Base
• - Ocutec Novalens Perception
• - Menicon SF-P Simultaneous
• - Unilens Simultaneous (also in high add)
• - Conforma VFL 3
• - GBF V/X, V/X 2 Crite, APA2
• - Breger Mueller Welt Zebra, Bullseye
• - Rand Scientific Transfocal
• - Univeral CL of FL New Image
• - Fused Kontacts Tangent Streak Multifocal
• - Danker DuraSil Bifocal, Visionall Multifocal
• - Concise Natural Vision
• - Abba Optical B-CAD
• - California Optics Cal Perm
• - C&H EP Vision
• - Contex MF-19, MF-23
• - Holo/Or Diffractive Lens (Israel)
• - Polymer Technology Corp. has three translating and four simultaneous investigational designs

Alternating Vision Bifocals:

• - C&H MP Vision
• - Paragon Vision Sciences FluoroPerm ST (various labs)
• - Contact Lens Technology Bi Perm T
• - Fused Kontacts Tangent Streak (included Trifocal)
• - Menicon SF-P Crescent or Decentered DeCarle
• - Metro Optics Metro-Seg
• - Salvatori ACC Translating and One Piece Crescent
• - Truform Solitaire I and II and Llevations
• - Universal CL of FL Translating
• - X-cel Solution

Note: Many other labs make RGP bifocals

HYDROGEL LENSES

Aspheric:

• - Adco Naturalvue
• - B&L PA-1 and Occasions
• - Blanchard Esstech
• - GBF V/X (and V/X toric)
• - LifeStyle LifeStyle 4-Vue, LifeStyle Xtra
• - Specialty UltraVision Frequency Progressive
• - Wesley Jessen (PBH) Hydrocurve II Bifocal
• - Preferred Optics ADDvantage
• - Premier Contact Lens Co. Fulfocus
• - Salvatori Allvue
• - Unilens Unilens Aspheric, SoftSITE
• - United Contact Lens UCL Multifocal (and UCL Multifocal Toric)

Concentric (cd = center distance, cn = center near):

• - Lombart BiSoft (cd)
• - OcuEase OcuFlex 53 (cn)
• - Sunsoft Multifocal (cn)
• - Unilens Simulvue (cn)
• - Westcon Horizon 55 BiCon, Horizon 55 BiCon Toric (cn)

Diffractive: Ocular Sciences/American Hydron Hydron Echelon

Note: there are no alternating vision soft bifocals.

ESTABLISH THE PATIENT'S COMMITMENT

At follow-up visits, I address any symptoms and record visual acuity. It may be necessary to reorder one or both lenses to accommodate the patient's desire for improved distance or near vision. At this visit, I establish the patient's commitment to the lenses and collect the remainder of the fee. If the patient is not happy with the vision provided by the simultaneous bifocal, I'll consider a translating design. Poor near acuity with acceptable distance vision is the main complaint with a simultaneous lens, especially among absolute presbyopes. If this is the case, I'll consider prescribing an alternating segment design, such as Paragon's Crescent bifocal or Fused Kontact's Tangent Streak.

ALTERNATING DESIGN OPTIONS WITH RGPs

The Tangent Streak alternating bifocal is a very successful design for absolute presbyopic patients. It provides good distance and near vision, but it's difficult to fit, expensive, and it sometimes compromises the cornea due to its thickness.

Alternating bifocal designs utilize a translating, near reading segment. While the reading add in spectacles is stable within the frame, the reading segment in a contact lens will move constantly if not stabilized. Truncation and prism are the primary methods of stabilizing a bifocal contact lens. For this reason and to determine segment height, I always trial fit alternating bifocal designs.

The position of the lens relative to the lower lid is critical in fitting an alternating RGP bifocal. The lower lid must be able to hold the lens and push it up upon down gaze to enable the patient to read through the near segment. Truncation and prism ballasting should help keep the reading segment at about the 6 o'clock position. Truncation will also help reduce lens rotation and aid
in smooth translation into the reading segment upon down gaze. Even with truncation and prism ballasting, the lens may still rotate, usually nasally. If so, alter the base of the prism up to 30 degrees to compensate for this rotation.

While upper lid attachment is usually desirable with simultaneous designs, lid capture in alternating designs will interfere with translation to the reading segment. Thinning the apex, flattening the cornea-base curve relationship and increasing prism will help reduce upper lid attachment. Increasing prism may reduce rotation and decrease upper lid attachment, but it will also increase the thickness of the lower edge of the lens which may contribute to 4 and 8 o'clock corneal staining.

The initial base curve selection should be flatter than normal to promote lens translation. Once you've selected a base curve, observe lens rotation. If rotation is minimal, determine segment height by calculating the difference between the segment height of the known trial lens and the desired segment placement within 0.3mm of the lower portion of the pupil in normal room illumination. To do this, use the calibrated illumination system of a slit lamp, making sure the beam is not so wide or so bright that it artificially constricts the pupil.

Once you've determined the segment height, perform the distance overrefraction. Your lens order should include base curve, truncated diameters, distance prescription, reading add, segment height, prism amount, prism rotation and lens material.

The initial dispensing of the alternating bifocal lens is exciting. Usually, the patient enjoys excellent distance and near vision. If the patient complains of a line in his vision, lower the segment either by increasing the truncation in the office or by reordering the lenses.

LID CAPTURE IN ALTERNATING DESIGNS WILL INTERFERE WITH TRANSLATION TO THE READING SEGMENT. THINNING THE APEX, FLATTENING THE CORNEA-BASE CURVE RELATIONSHIP OR INCREASING PRISM WILL HELP REDUCE UPPER LID ATTACHMENT.

CONFIRMING SUCCESS

At the two-week exam, I reevaluate distance and near vision and may reorder slight overrefractions. I also verify segment heights for translating designs and, most importantly, monitor corneal integrity. If there's desiccation staining adjacent to the lens, I may modify the lens edge and recommend rewetting drops to help decrease corneal staining and lens dryness. CLS

Dr. McLaughlin is an assistant professor of clinical ophthalmology at The Ohio State University in Columbus. His practice is limited to contact lenses and sports vision analysis.