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Retina, technology updates highlight Hawaii 2003
High points of the meeting included the popular cataract and refractive complications panels chaired by Manus C. Kraff, MD, and Richard L. Lindstrom, MD, respectively.
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MAUI, Hawaii — More than 1,000 ophthalmic professionals, including more than 700 physicians, gathered here for Hawaii 2003: The Royal Hawaiian Eye Meeting last month.
In addition to escaping the record low temperatures that held sway over most of “the mainland” in January, attendees were treated to a full program that highlighted all aspects of clinical ophthalmology, as well as practice management and reimbursement issues.
The Retina 2003 meeting, also sponsored by SLACK Incorporated, publisher of Ocular Surgery News, and the Hawaii 2003 program, “Retina Update for the Anterior Segment Surgeon,” were well-attended, perhaps due interest in the expanding treatment options in development for retinal disorders.
Many faculty presented interim reports on technology and techniques in development, including customized ablation, new technologies in IOLs, new modalities for dry eye and other ocular ailments.
As in years past, the keynote presenter at Hawaii 2003 was an inspirational speaker. His story of achievement in the face of adversity set the tone for a week in which many of the most recent advances in ophthalmology were presented and discussed.
Being in a leadership role means making promises that may be hard to keep, but “you do it because it makes the team better,” said Jim “The Rookie” Morris, who gave the highlighted talk here at the meeting.
Originally a top baseball prospect, Jim Morris’ dream of becoming a major league player came to a halt when he suffered serious arm injuries in the minors.
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At the age of 35 and 11 years after retiring from the minor league, Mr. Morris made a bet with his last-place high school team that if they won the district championship, he would try out for a major league team. Mr. Morris’ story was immortalized in the movie “The Rookie.”
Mr. Morris told attendees, “What it came down to was, I made a promise I was going to live up to.” Packing up his three children and some of his pride, Mr. Morris drove an hour to try out for Tampa Bay’s minor league team.
When he had played in the minor leagues in his late teens, Mr. Morris pitched balls somewhere in the mid-80s. During this tryout, he was clocked throwing balls at 96 miles per hour.
“My first thought was, ‘Wow, I’m throwing at 96 miles per hour. I’m throwing baseballs at 96 miles per hour at high school kids. The lawyers are going to have a field day.’
“What makes me an inspiration to other people? I don’t honestly know,” he said. “Life is funny. It throws you curves. You gotta be able to do things and put forth an effort like anything else. You have to be able to hear ‘no,’ but not take ‘no’ as an answer. Being a team leader means showing what you’re made of. Dreams do exist and you can make them happen.”
If anything, Mr. Morris said the experience of trying out for a major league baseball team at the age of 35 taught him that “you have to be able to laugh at yourself. Other people are all too willing to stick a knife in your back to prevent you from achieving your goals.”
Speaking about the movie based upon his life, Mr. Morris said, “God had a plan for me. It’s not about me, it’s about an event. Enjoy what you have while you have it. And don’t take ‘no’ as an answer.”
Pharmacia supported the appearance by Mr. Morris.
| RETINA/VITREOUS |
Managing epiretinal mebranes
Diagnosing and managing epiretinal membranes and macular holes can be difficult, according to one surgeon.
“Epiretinal membrane problems are common in about 15% of patients, and about 70% have some form of epiretinal problems,” said Carmen A. Puliafito, MD, MBA. “I suspect that these problems are associated with postoperative cystoid macular edema.”
He added that epiretinal membranes are mostly associated with “relatively good vision and are not progressive; they’re stable over long periods of time. Some may require vitreous surgery and some are associated with macular edema.”
Dr. Puliafito acknowledged that there are “sleeper” cases that are difficult to manage and diagnose.
When it comes to fixing macular holes, “you need to tell your patients the facts,” Dr. Puliafito said. This includes the 100% incidence of cataract after vitrectomy, he added.
“Macular holes can be a very, very confusing syndrome,” he said. After a patient has had a macular hole for 2 or 3 years, surgery may be able to close the hole, but the patient’s vision will not improve, he said.
“Early stage macular holes are the ones we like to operate on,” Dr. Puliafito said. “You really want to operate on them when they’re 20/50 or 20/70.”
Higher resolution OCT
Ultrahigh-resolution optical coherence tomography represents “a very new technology that can improve the resolution and discriminate the clean layer to the retina by fivefold,” according to one presenter.
Ultrahigh-resolution optical coherence tomography (OCT) allows high-resolution cross-sectional optical imaging of ocular structures. It is a noncontact, noninvasive technique that uses short-wavelength coherent light to achieve improved resolution.
According to Joel S. Schuman, MD, although the technology is now in the laboratory stage and is not close to commercial availability, ultrahigh-resolution OCT will allow better evaluation of retinal anatomy and pathology in vivo.
Although ultrahigh-resolution OCT is not available, Dr. Schuman noted that there has been an update of OCT technology recently. The OCT 3, also called Stratus OCT, from Carl Zeiss Meditec, is an advancement over earlier versions of OCT because of its ability to achieve higher resolution, he said.
“The OCT 1 and OCT 2 have axial resolution of approximately 10 to 15 µm, but the OCT 3 has resolution of 8 to 10 µm,” he said.
“Ultrahigh-resolution optical coherence tomography is a exciting technique because practitioners have the capability to better view details,” Dr. Schuman said. He said it will represent a further improvement in resolution of 2 to 3 µm.
“The detail with the ultrahigh-resolution OCT allows ophthalmologists to actually see the photoreceptors and the possible abnormalities for each patient,” he said. “This is the first time that we’ve been able to accomplish such detail.”
| REFRACTIVE SURGERY |
ICL for high corrections
The STAAR Surgical ICL improves quality of vision in highly myopic and highly hyperopic patients, allows for additional refractive surgery and minimizes corneal complications, according to Howard V. Gimbel, MD, FRCSC.
The STAAR ICL requires only a 3-mm incision for implantation and can be removed through an incision of the same size if a cataract develops later in life, he said.
Dr. Gimbel discussed 251 patients (222 myopes and 29 hyperopes) implanted with the newest ICL model, the V4, over a 3-year period.
Early results of the lens for both myopic and hyperopic patients are “very promising,” Dr. Gimbel said. Few complications were seen, and stability was achieved early in the postoperative period, he said. Proper sizing and vaulting are paramount to success, he added.
“Vaulting can vary from patient to patient, and even from eye to eye for the same patient,” Dr. Gimbel said. “We’ve seen no anterior chamber opacity as we’ve gone to more aggressive vaulting.”
Lensectomy for hyperopes
Refractive lensectomy with multifocal implant is an alternative to refractive surgery for select presbyopic hyperopes and borderline cataract patients, said Frank A. Bucci Jr., MD.
“Key factors include careful patient selection accurate biometry and meticulous surgical technique,” he said.
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Dr. Bucci implanted the AMO Array multifocal IOL in 84 hyperopic eyes of 50 patients. He performed astigmatic keratotomy at least 3 weeks later for patients with 0.75 D or more of astigmatism. All eyes were 20/40 or better postoperatively, with more than 90% at J2 or better near vision.
These results demonstrate that hyperopic lensectomy with the Array multifocal implant is a safe and effective refractive procedure that provides patients with improvements in distance, intermediate and near vision, Dr. Bucci said.
“Managing the astigmatism is mandatory for patient satisfaction,” Dr. Bucci said. He prefers postoperative astigmatic keratotomy over an intraoperative technique.
“Surgeons should avoid patients with unrealistic expectations, those who are obsessive-compulsive types, highly introspective people, people with high demands for near work or night driving and people who already complain of glare preoperatively,” he said.
Dual lens system
A combination of two IOLs from STAAR Surgical may facilitate accommodation following clear lensectomy and cataract extraction, according to Raymond M. Stein, MD. He coined the term “DualFlex” to describe his double implantation technique.
“The DualFlex was initially developed to treat hyperopic patients who required more power than what was available in a single lens,” Dr. Stein said. In a small study, the double implants not only corrected hyperopia but also appeared to provide an accommodative effect, he said.
The study consisted of 24 eyes of 13 patients. Patients ranged from +5 to +16 D, and all underwent clear lens extraction. The surgeon placed a STAAR Surgical standard silicone plate-haptic lens in the capsular bag and a STAAR three-piece IOL in the sulcus.
Postoperatively, 15 of the 24 eyes (63%) had uncorrected visual acuity of 20/40 or better for distance vision, and 83% were J4 or better for near. Additionally, 71% could see J3 or better with only distance correction in place. Thirteen eyes (54%) were 20/40 or better for distance and J4 or better for near.
Near vision correction has remained stable in all patients who received the dual lens implants with an average of 13 months follow-up, Dr. Stein said.
Dr. Stein said further study will investigate the optimum power distribution of the IOL in the bag vs. the sulcus and whether satisfactory results can be achieved in myopic eyes.
Nomogram key in LASIK
An accurate nomogram is essential in maintaining a high standard of patient care in LASIK, according to Kerry D. Solomon, MD.
“A nomogram allows better results and earlier visual recovery,” Dr. Solomon said.
By minimizing risks associated with enhancements and reducing the number of office visits, surgeons can improve time and cost-efficiency in their practices, he said.
Several elements can improve one’s nomogram, Dr. Solomon said. A surgeon must have an effective software program and a well-educated staff willing to input, track and recheck data.
“Garbage in is garbage out, so all staff should be well trained,” Dr. Solomon said.
He also said the surgeon must take meticulous preoperative refractions, as well as refractions at 1 month, 3 months and later, if necessary. As much data as possible should be recorded, such as pachymetry and intraocular pressure, Dr. Solomon said.
Dr. Solomon suggested taking steps to ensure consistent surgery and paying careful attention to the nomogram.
Dr. Solomon also recommended close attention to proper fixation and centration. He said surgeons should consider increasing the flash rate of the fixation light to help patients stay focused and adding a reticle, which allows the surgeon to keep the eye centered.
Super-speed tracking
The CustomVis Solid State 213 nm laser showed promising results when used on three patients with irregular astigmatism, said John A. Vukich, MD.
The CustomVis laser is a diode pumped quintupled Nd:YAG laser with a gaussian 0.6-mm random spot and a 300 Hz pulse repetition rate.
Dr. Vukich said the laser makes super-speed tracking possible because of its dual eye trackers (analog and digital), 5 kHz sensing and 1 kHz total closed loop response. He said this makes the device 10 times faster than any other commercially available laser. The laser also features limbal tracking, which eliminates the need for pupil dilation.
Dr. Vukich presented results from three patients treated in September. In the first patient, the anterior surface was smoothed, with best corrected visual acuity (BCVA) improving from 20/30 to 20/20. Keratometric cylinder decreased more than 3 D.
In the second patient, at 1 week postop, uncorrected visual acuity (UCVA) was equal to preop BCVA (20/30) and keratometric cylinder decreased more than 3 D.
In the third patient, despite an overcorrection in spherical error, BCVA improved from 20/40 to 20/30, refractive cylinder decreased by 6.5 D, and keratometric cylinder by almost 8 D.
Artisan in high myopes
The Ophtec Artisan phakic IOL is a safe and effective device for correction of high myopia, according to Kerry K. Assil, MD. Preliminary results of a phase 3 Food and Drug Administration trial show that the lens has a low rate of complications. Follow-up to date in the U.S. trial is 3 years, Dr. Assil said.
The trial includes 971 eyes of 560 patients, he said. Preoperative error ranged from –5 D to –20 D.
“The stability of this lens was extreme,” Dr. Assil said.
LASIK can be “quite easily performed” on these patients with a low incidence of adverse events, he said.
According to Dr. Assil, UCVA improved postoperatively to 20/40 in all patients. No cases of IOP elevation, endothelial cell loss, loss of BCVA, pupil decentration, cataract formation or persistent uveitis have been reported, Dr. Assil said.
The key to successful surgery is to carefully choose patients, he added.
“Exclude those with protruding irises,” he said. “Surgeons need to be well-trained in this technique, but all the complications appear transient.”
Ketorolac for PRK
A clinical study evaluating a new formulation of ketorolac tromethamine confirmed that it treats ocular pain associated with photorefractive keratectomy.
John R. Wittpenn Jr., MD, said a new formulation of Acular (ketorolac tromethamine 0.4%, Allergan) is “safe and effective for pain control post-PRK.” The formulation provided significant relief of ocular pain, and its use also reduced the amount of oral narcotic analgesic needed.
Pain intensity was higher for patients who received vehicle alone than for those in the treatment group. The percentage of patients needing oral narcotic analgesics was significantly higher in the vehicle group.
The study design comprised two identical multicenter, randomized, double-masked, parallel-group studies using ketorolac tromethamine 0.4% or vehicle.
Each patient was dosed with either treatment four times a day for up to 4 days postoperative or until no pain was experienced. Patients were evaluated daily after surgery and were followed until re-epithelialization occurred. No adverse events were reported.
“There was a dramatic effect that persisted throughout the study,” Dr. Wittpenn said. “Stinging was much less in the treatment group than in the vehicle group.”
Larger optical zones
Surgeons should use large optical zones to reduce higher-order aberrations when performing customized ablation, according to Scott MacRae, MD.
Dr. MacRae said there are three important values to remember when performing customized wavefront: scotopic pupil diameter, wavefront aperture diameter and ablation optical zone diameter.
“Pupil size determination is critical in higher-order aberration correction,” he said.
He assessed 340 eyes that underwent customized LASIK with the Bausch & Lomb Zyoptix system to determine the correlation, if any, between pupil diameter and higher-order aberrations pre- and post-LASIK.
The mean scotopic pupil size was 6 mm, but “a greater aperture is recommended because many pupils are larger than 6 mm in real scotopic conditions,” he said. Dr. MacRae found 42% of patients had scotopic pupil sizes larger than 6 mm.
He said an optical zone between 6.5 mm and 7 mm is more effective at reducing higher order aberrations than optical zones smaller than 6 mm.
Gel-assisted LASEK
Gel-assisted and alcohol-assisted laser epithelial keratomileusis were equivalent in efficacy in a small study, said Marguerite B. McDonald, MD.
She presented early results in the first 15 patients of a 50-patient study to compare gel-assisted LASEK to alcohol-assisted LASEK. Dr. McDonald said gel-assisted LASEK involves stripping the epithelial layer mechanically without alcohol while the eye is briefly under suction from a microkeratome ring. The sheet is then manipulated with the aid of GenTeal Gel (Novartis). All eyes in her study were myopic or myopic with astigmatism and were randomized to receive either alcohol-assisted or gel-assisted surgery.
A greater percentage of gel-assisted eyes than alcohol-assisted eyes were within 0.5 D of emmetropia postoperatively.
Dr. McDonald said these interim results “demonstrated significant differences in favor of alcohol at 1 week, in favor of gel at 1 month and no significant treatment differences at 3 months.”
Topography pearls
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While the current hot topic in refractive surgery is wavefront, surgeons must not overlook the importance of corneal topography as a screening tool, said Stephen Klyce, PhD.
“The number of LASIK litigations has shot up, and the need for adequate screening with corneal topography has never been greater,” he said. He offered several pearls “to help keep a plaintiff-free zone around your practice.”
Buy smart, he said. Ensure that the topographer you select has adequate contrast between adjacent colors to make recognition of irregular astigmatism easier. Use the axial power map for routine clinical exams, he added. Keep it simple: Program the topographer to record “only what you really need to screen a patient,” he said.
He showed a preoperative corneal elevation map with a steep, red area. “If the cornea develops instability post-LASIK, can you testify this map was normal? It might be, but ‘might’ is never good enough in court,” he said.
Also make sure the topographer is calibrated correctly. “If you suspect abnormal topography behavior, go through the calibration exercise,” he said.
Dr. Klyce said regardless of what the topography will be used for, always examine both eyes. “One eye might look perfectly normal while the other is pathological. The pathology in one eye often forecasts emerging pathology in the other eye,” he said.
| PEDIATRICS/STRABISMUS |
Stereoacuity and alignment
The duration of misalignment affects the quality of stereoacuity in patients who develop stereopsis in the treatment of congenital esotropia, a study showed.
Malcolm R. Ing, MD, and colleagues compared Titmus stereoacuity results with the duration of alignment in a group of patients who underwent surgical alignment by 24 months of age.
“The purpose of our comparison was to determine whether the age at alignment or duration of misalignment before surgery affected the stereoacuity result,” Dr. Ing said. “The present study shows a larger time window for the development of Titmus stereoacuity.”
The age at alignment and duration of misalignment for 90 patients (mean age 9 years, 9 months) was correlated with the percentage of patients with stereopsis and quality of the stereoacuity result as determined by the Titmus vectograph overlay.
A smaller percentage of patients aligned after 12 months of age achieved stereopsis (P <.05, power 0.8), Dr. Ing said. The quality of stereoacuity was decreased for patients with a duration of misalignment longer than 12 months
(P = .001, power 0.8), he said.
In the study, 74% of patients demonstrated stereopsis. The quality of stereoacuity was 51% at 0 to 12 months, and this dropped to 19% at 13 to 21 months. “No patients throughout the study attained stereopsis after 18 months of misalignment,” Dr. Ing said.
| CATARACT/IOL |
Light-adjustable lens
A silicone IOL in early human testing may have the potential for highly precise refractive results following cataract surgery, according to Randall J. Olson, MD.
Dr. Olsen said the Light Adjustable Lens (LAL) from Calhoun Vision has the potential to correct lens power postoperatively and provide precise refractive results in cataract patients.
The LAL is a silicone lens containing unattached monomers that can be cross-linked to an underlying lens matrix using an appropriate amount of light, he said.
Dr. Olson cited studies by Nick Mamalis, MD, that show the accuracy for spherical correction with the LAL may be ± 0.1 D or better.
The lens is currently being developed for correction of sphere. However, Dr. Olson said cylindrical and multifocal corrections may also be possible.
Dr. Olson noted one drawback to using the lens is that once it receives its final adjustment the eye must be protected from significant amounts of light until the lens is “locked” to that adjustment.
Pupil size is also a consideration in patient selection.
“You need good pupil dilation to see the lens,” he said. “You can’t put it in a small-pupil patient.”
Reversing the Toric IOL
It is possible for the Toric IOL from STAAR Surgical to rotate in the eye, thereby decreasing the astigmatic correction it provides. However, a study shows reversing the IOL’s position may improve its stability.
Stephen S. Bylsma, MD, said he often reversed the IOL, front-to-back, to correct patients with astigmatism of less than the available cylindrical powers. In doing so, he found there was less rotation of the lens in these patients. Rotation occurs in 5% of patients with standard implantation, he said.
Dr. Blysma performed a study to determine whether the lens was more stable reversed than in its intended position. He retrospectively evaluated 124 eyes with Toric lenses in the standard position and 47 eyes with lenses reversed.
Of the 171 eyes evaluated, 83% had UCVA of 20/40 or better in the reversed position, Dr. Blysma said. In the standard position, 60% achieved the same results.
“The data reveals that regardless of the Toric power, position or model, (patients with the lens reversed) had a statistically significant improvement,” Dr. Bylsma noted.
Preventing PCO
The right IOL design and the right surgical technique can reduce the risk of posterior capsular opacification, said Steven H. Dewey, MD.
Dr. Dewey said he prefers the AMO Sensar OptiEdge lens, which has shown low incidence of PCO, photopsia and other complications. He recommends inserting the three-piece lens through incisions of 3 mm or smaller.
Dr. Dewey noted that PCO can be reduced with attention to six factors identified by David Apple, MD, three surgeon-related and three design-related.
The three surgical concerns include excellent cortical cleanup with hydrodissection. “IOL insertion is doomed to fail without thorough cortical removal,” he said. In-the-bag fixation and a capsulorrhexis diameter smaller than the optic diameter are the other two surgical factors that help prevent PCO.
Dr. Dewey said Dr. Apple identified biocompatibility, an IOL design that contacts the posterior capsule, and a square optic edge as the three IOL factors that reduce PCO.
Square-edged optics are the best advancement in preventing PCO and in developing micro-incision surgery, Dr. Dewey said. “These lenses offer a new standard in symptom-free visual rehabilitation after cataract surgery,” he said.
Technique for 4+ nucleus
Special techniques for removing the 4+ nucleus with phaco were discussed by Roger F. Steinert, MD.
“The 4+ nucleus is a real challenge. When I say 4+ nucleus, I mean the ones that basically look like molasses or Coca-Cola,” Dr. Steinert said.
He said the keys to 4+ nucleus phaco are visualizing the anterior capsule, minimizing capsular stress and protecting the posterior capsule and endothelium.
“Visualizing the capsule involves careful focus. Oblique illumination is still a wonderful adjunct at times,” Dr. Steinert said. “And capsule stains have revolutionized our ability to deal with these 4+ nuclei.”
The material that is currently available for capsule staining in the United States, indocyanine green, is expensive and requires a cumbersome dilution process, Dr. Steinert said. He said a less expensive option is VisionBlue (trypan blue, DORC), but this liquid stain is not currently available in the United States.
“Methylene blue should never be used. It is tempting because it looks the same,” Dr. Steinert said. Methylene blue is toxic to the endothelium as it is currently supplied, he said. Fluorescein, another option, is difficult to see without a cobalt blue filter, he added.
Because 4+ nuclei are thick, Dr. Steinert recommended using a sharp cutting chopper. He said the alternative is to groove the nucleus before the initial chop or to crack it before chopping.
The 4+ nucleus has a tough posterior layer. By using the chopper as a hook, surgeons can snap the bridging fibers to remove the nucleus, Dr. Steinert said.
The posterior capsule, which can be thin in these eyes, should be protected with an “artificial epinucleus,” to serve as a barrier against sharp fragments, he said. This can be created by injecting a retentive viscoelastic behind the remaining nucleus.
“Use a technique that is comfortable for you,” Dr. Steinert summarized. “Use a technique that you can use for your piece-of-cake cataract and your 4+ nucleus.”
Blue light phototoxicity
The Alcon AcrySof Natural IOL filters ultraviolet and blue light similar to a precataractous crystalline lens, according to Donald N. Serafano, MD.
“The AcrySof Natural IOL is designed to transmit light in order to approximate the human crystalline lens,” Dr. Serafano said. “The human lens and macular pigment are designed to filter hazardous UV and blue light. When the natural crystalline lens is removed during cataract surgery, the level of protection against UV and near-UV light decreases.”
Clinical studies have shown that the AcrySof Natural IOL is effective and safe, Dr. Serafano said. The addition of a yellow chromophore has not negatively affected visual outcomes.
“The yellow color of the chromophore gives ophthalmologists a better view of the inserted IOL,” he said.
In a recent clinical study, the AcrySof Natural IOL did not negatively impact color vision. There was also no significant difference in contrast sensitivity among various models of the AcrySof IOL.
Providing long-term protection against UV and blue light will be a standard for IOLs in the future, he said.
Reducing endophthalmitis
The rate of endophthalmitis is rising in the United States, said I. Howard Fine, MD. “We have to realize that when we’re doing more surgery, we’re going to see more complications,” he said.
Factors that influence the rise in postoperative endophthalmitis include higher rates of resistance to antibiotics and an emphasis on faster procedures.
“The best way to prevent endophthalmitis is to pay attention to detail,” Dr. Fine said. “In our practice, we have not have one incident of postoperative endophthalmitis in 4,000 cases over 5 years. I don’t think that this is due to good luck. I think it’s due to a concerted effort to pay attention to detail at the time of surgery.”
Dr. Fine said it is crucial that surgeons take their time and not be over-aggressive in their techniques. When performing cataract extraction, surgeons must carefully prepare the surgical field, select an appropriate viscoelastic and make an incision that will promote sealing.
| CORNEA/EXTERNAL DISEASE |
Omega-3 for dry eye
Supplementation of omega-3 fatty acids with enriched flaxseed oil can provide the foundation for a broad spectrum of therapies for dry eye, according to Jeffrey P. Gilbard, MD.
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“As a population we are omega-3 starved,” said Dr. Gilbard, founder and president of Advanced Vision Research, which makes tear supplements.
Omega-3, which must be obtained by the body through diet, addresses the root causes of meibomitis and dry eye by decreasing inflammation, he said.
“I see omega-3 taking a great role in treating dry eye and blepharitis,” he said.
Studies are under way with Thera Tears Nutrition (Advanced Vision Research), a patent pending enriched flaxseed oil, to evaluate its dry eye treatment possibilities.
Anti-infective effectiveness
The effectiveness of antibiotics can be determined by measuring the drugs’ minimal inhibitory concentration, studying its pharmacokinetics and determining the speed of bacterial killing, according to Richard J. O’Callaghan, PhD.
Dr. O’Callaghan said not only is a drug’s ability to inhibit bacterial activity important, but also its penetrability and its ability to resist being secreted.
A bacterial strain’s susceptibility to inhibition by an antibiotic is described by its minimal inhibitory concentration (MIC) value.
“The determinations of susceptibility by the MIC method provide ophthalmologists with data descriptive of the interaction of the drug with the bacterium isolated from a specific infection,” he said.
He added, “Effectiveness is the best measurement of what works best.”
Cytology of external disease
“Cytology has often been overlooked as a means to diagnose opportunistic organisms,” said Henry D. Perry, MD.
Confirmation of a clinical diagnosis can be easily completed by cytology, Dr. Perry said. Cytology is beneficial in determining differential diagnosis. In some cases it provides a specific cause, resulting in a new treatment plan.
In order to make cytology work in one’s practice, Dr. Perry said certain equipment is needed. A Kimura spatula has an “anvil-like” shape at the end. “The spatula is helpful for digging out debris from the edge of a corneal ulcer and for making scrapings,” he said.
A Coplin jar, methyl alcohol and cytology slides are also needed.
To illustrate the value of this diagnostic modality, Dr. Perry presented several cases including a 56-year-old black female who was treated for 2 years for superior limbic keratoconjunctivitis. A conjunctival scraping showed characteristics of inclusion conjunctivitis due to Chlamydia. The patient was then treated with systemic tetracycline, and within 1 week she was asymptomatic and showed resolution of her chronic keratoconjunctivitis.
“Cytology is something we should consider especially when we suspect a corneal problem is due to an opportunistic organism which would require a special, not easily available, medium to confirm diagnosis, or when culture confirmation may take up to several weeks,” Dr. Perry said. “I feel strongly that cytology can save eyes.”
Antibiotics and wound healing
The epithelial surface is a barrier to infection, but this surface may become compromised by preoperative and postoperative medications, as well as by surgery itself, said Robert W. Snyder, MD, PhD.
Dr. Snyder said antibiotics can delay epithelial healing after PRK, and patients with corneal ulcers treated with antibiotics may develop precipitates.
Additionally, ophthalmic preservatives have been shown to have toxic effects in animal studies.
Dr. Snyder warns that during LASIK excess anesthetic use can loosen the attachment of the epithelium to Bowman’s layer. Loose basal membrane can lead to sloughing during the microkeratome pass, putting the patient at risk for epithelial ingrowth and diffuse lamellar keratitis (DLK).
Epithelial problems can also be seen with laser epithelial keratomileusis (LASEK), Dr. Synder said. Ethanol and preoperative anesthetics can loosen surface epithelium attachments to Bowman’s layer.
“Prewarmed irrigation fluids and medications may enhance the weakening of epithelial attachments,” he said.
Postoperative nonsteroidal anti-inflammatory drugs (NSAIDs) and antibiotics should be used with caution, as these also delay healing, and preservatives in NSAIDs can result in ultrastructural changes in the corneal epithelium.
“I’m a big proponent of NSAID use because of the pain management aspect after cataract surgery,” Dr. Snyder said. “But you need to be wary of using these on patients with dry eye, those who are diabetic or immunocompromised patients.”
More to come
Look for further coverage of Hawaii 2003 in upcoming issues of Ocular Surgery News.
In the Practice Management section of our next issue (March 1) we will present updates from the meeting’s practice management sessions.