Complications of radial and transverse keratotomy

Implantation of a toric intraocular lens after repeated radial keratotomy procedures: A case report

Corneal alterations due to radial keratotomy (RK) complicate intraocular lens calculations, which may explain why there have been few reports of toric intraocular lens (TIOL) implantation after excessive or multiple operations. A 71-year-old male with a history of repeated RKs and at least 30 corneal incisions in each eye was referred for cataract surgery. Preoperatively, the best-corrected distance visual acuity was 0.7 decimal (0.15 logMAR) in the right eye and 0.9 decimal (0.05 logMAR) in the left eye. The refractive errors were -8.00 -3.00 × 80 and -6.00 -3.50 × 80, respectively. The total corneal cylindrical powers (real power; anterior and posterior) were, respectively, -0.90 D and -3.60 D at 9 a.m., compared to -1.60 D and -3.80 D at 1 p.m. Corneal astigmatism in the left eye was considered symmetric and diurnally stable; therefore, an XY1AT6 TIOL (Hoya, Tokyo, Japan; cylindrical power at the plane, +3.75 D) was implanted. A non-toric intraocular lens, the XY1 (Hoya), was implanted in the right eye. Six-month postoperative best-corrected distance visual acuities were 1.2 decimal (-0.08 logMAR) and 1.0 decimal (0.00 logMAR) in the right and left eyes, respectively. Post-operative manifest refractions were +0.00 -3.00 × 70 and -1.00 -2.00 × 85, respectively. The TIOL reduced refractive astigmatism in the left eye; therefore, we believe that even after multiple RKs, the TIOL can be a suitable candidate to correct astigmatism if the corneal astigmatism is diurnally stable and symmetric.

Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy

PURPOSE

To evaluate the outcome of sequential customized therapeutic keratectomy (SCTK) in reducing higher order aberrations (HOAs) and improving quality of vision in highly aberrated corneas consequent to previous radial keratotomy (RK).

METHODS

A retrospective review of patients undergoing SCTK treatment from January 2012 to October 2020 was conducted in the Eye Center, Humanitas Clinical and Research Center (Rozzano, Italy). Indications for treatment in patients who had RK were significantly and/or progressively reduced corrected distance visual acuity (CDVA) combined with visual symptoms critically affecting quality of life. Preoperative and postoperative CDVA, corneal topography and aberrometry, Scheimpflug tomography, and anterior segment optical coherence tomography were registered.

RESULTS

Thirty-four patients who underwent RK a mean of 26.62 ± 7.10 years before SCTK treatment were included. SCTK induced a significant improvement of CDVA from 0.44 ± 0.82 logMAR preoperatively to 0.15 ± 0.64 logMAR postoperatively (P < .001). No patient experienced worsening of CDVA, whereas 8 patients (23,50%) gained one line and 23 patients (67.65%) gained two lines or more. A significant decrease in corneal coma, trefoil, and spherical aberrations was also noted (P = .003, .003, and .004, respectively).

CONCLUSIONS

SCTK proved to be a safe and effective option to treat highly aberrated eyes following RK. The authors suggest the use of SCTK as a first-line approach for the treatment of HOAs after RK and avoiding more invasive procedures such as corneal transplantation or intraocular lens implantation. [J Refract Surg. 2023;39(12):808-816.].

Rare case of corneal keloid following radial keratotomy for myopia

An adult male in his 50s presented with complaints of glare and gradual, painless, progressive diminution of vision in the right eye (RE). Visual acuity in RE was noted to be 2/60, and slit lamp biomicroscopy revealed a pearly grey-white elevated corneal opacity measuring 4 mm × 3 mm, obscuring the visual axis. There was no history of ocular trauma or infection. The patient had undergone bilateral radial keratotomy for myopia correction 25 years ago. Anterior segment optical coherence tomography imaging demonstrated increased corneal thickness of 1080 µm at the site of lesion and the height of the epicorneal mass was noted to be 493 µm. The patient underwent fibrin glue-aided anterior lamellar keratoplasty. Histopathological examination of the excised host tissue confirmed the diagnosis of corneal keloid.

A rare case of infectious keratitis that developed 27-years after radial keratotomy

Purpose

To report a rare case of bacterial infectious keratitis that developed 27 years after radial keratotomy.

Observations

A 48-year-old female who underwent bilateral radial keratotomy (RK) 27-years previous presented at our department with pain and visual loss in her right eye after being diagnosed with bacterial keratitis by her primary care physician. Slit-lamp examination showed a focus at the deep layer of the cornea, endothelial plaque, and hypopyon. Treatment with topical fortified levofloxacin and cefmenoxime eye drops was initiated. However, at 2 days after the initiation of treatment, there was no improvement, so anterior chamber irrigation and a bacterial smear/culture were performed. The smear showed many gram-positive cocci, yet no organism was detected in the culture. We suspected the causative bacteria to be methicillin-resistant Staphylococcus aureus (MRSA) due to her job (i.e., nursing staff) and the treatment course. Thus, we initiated treatment with 0.5% arbekacin eye drops for the suspected MRSA keratitis, and it was effectively controlled.

Conclusions and Importance

The findings in this case indicate that the incisions used for RK are delicate/fragile and can easily open doors to infection, as they remain unstable for many years post surgery.

Accuracy and safety of partial thickness femtosecond laser radial and arcuate keratotomy incisions in porcine eyes

Background

To evaluate the accuracy and safety of micro radial and arcuate keratotomy incisions constructed by a femtosecond laser system with a curved contact patient interface in porcine eyes.

Methods

Partial thickness micro radial and arcuate keratotomy incisions were constructed in porcine eyes with a femtosecond laser system and evaluated for precision of depth, quality, and consistency. Optical coherence tomography was used to determine the accuracy and precision of incision depth. Corneal endothelial safety was assessed by a fluorescent live/dead cell viability assay to demonstrate laser-induced endothelial cell loss. Quality was evaluated by ease of opening and examination of interfaces.

Results

In two micro radial incision groups, intended incision depths of 50% and 80% resulted in mean achieved depths of 50.01% and 77.69%, respectively. In three arcuate incision groups, intended incision depths of 80%, 600 μm or 100 μm residual uncut bed thickness resulted in mean achieved depths of 80.16%, 603.03 μm and residual bed of 115 μm, respectively. No loss of endothelial cell density occurred when the residual corneal bed was maintained at a minimum of 85–116 µm. The incisions were easy to open, and interfaces were smooth.

Conclusions

A femtosecond laser system with curved contact interface created precise and reproducible micro radial and arcuate keratotomy incisions. Accuracy and precision of the incision depth and preservation of endothelial cell density demonstrated the effectiveness and safety of the system.

Outcomes of Femtosecond Laser-Assisted Cataract and Refractive Lens Surgery in Patients with Prior Radial Keratotomy

PURPOSE

To investigate outcomes of femtosecond laser (FL-) assisted cataract surgery (FLACS) and refractive lens exchange (RLE) in patients with prior radial keratotomy (RK).

SETTING

Single clinical practice.

DESIGN

Retrospective observational case series.

METHODS

All patients with prior RK undergoing FLACS- or FL-assisted RLE surgeries over a 6-year period were reviewed. Inclusion criteria were diurnal stability and stable manifest refraction. Exclusion criteria included any other incisional corneal surgery, macular or glaucomatous pathology, or vision loss from any other cause. Data collected included demographics, visual acuity, laser settings, and complications. Main outcome measures were intra- and postoperative complications and visual outcomes. Safety and efficacy indices were evaluated.

RESULTS

Sixteen eyes of 9 patients were included. Average age and follow-up time were 59.9 ± 9.9 years (range 44-75 years) and 3.3 ± 2.5 months, respectively. Average number of RK cuts was 11.8 ± 5.3 (range 8-20). Mean preoperative UDVA and CDVA were 0.9 ± 0.4 logMAR (Snellen 20/160) and 0.2 ± 0.3 logMAR (Snellen 20/30), respectively. Two intraoperative anterior capsule (AC) tears were identified. One postoperative IOL dislocation occurred. Postoperatively, the mean UDVA and CDVA were 0.2 ± 0.2 logMAR (20/30) and 0.1 ± 0.1 logMAR (20/25), respectively. Safety index was 1.6 and efficacy index was 1.2.

CONCLUSIONS

FLACS- or FL-assisted RLE surgery in RK patients has a high risk of anterior capsule tear and should be avoided. Thickened incisional scars are potential sources of incomplete laser penetrance. Toric lens implantation in RK eyes provide unpredictable astigmatic correction and should also be avoided.

Light Adjustable Intraocular Lens for Cataract Surgery After Radial Keratotomy

PURPOSE

To describe a case of light adjustable lens implantation after radial keratotomy.

METHODS

A patient with a 30-year history of radial keratotomy subsequently underwent phacoemulsification with implantation of intraocular light adjustable lenses. Serial refractions were performed at varying hours of the day postoperatively and were repeated for 3 months. The light adjustable lenses were adjusted twice, and the refractive power of the implant was eventually locked.

RESULTS

The patient was able to achieve uncorrected distance visual acuity of 20/25 in both eyes, improving from 20/125 in the right eye and 20/80 in the left eye, with no surgical complications.

CONCLUSIONS

The authors report the first case of light adjustable lens implantation after radial keratotomy, which has yielded promising results for mitigating intraocular lens miscalculations after radial keratotomy. [J Refract Surg. 2020;36(12):852-854.].

Finite Element Analysis of Air Gun Impact on Post-Keratoplasty Eye

Purpose

Due to the mechanical vulnerability of eyes that have undergone penetrating keratoplasty (PKP), it is clinically important to evaluate the possibility of corneal wound dehiscence by blunt impact. We have previously developed a simulation model resembling a human eye based on information obtained from cadaver eyes and applied three-dimensional finite element analysis (FEA) to determine the physical and mechanical response to an air gun impact at various velocities on the post-PKP eye.

Methods

Simulations in a human eye model were performed with a computer using a FEA program created by Nihon, ESI Group. The air gun pellet was set to impact the eye at three-different velocities in straight or 12° up-gaze positions with the addition of variation in keratoplasty suture strength of 30%, 50% and 100% of normal corneal strength.

Results

Furthermore to little damage in the case of 100% strength, in cases of lower strength in a straight-gaze position, wound rupture seemed to occur in the early phase (0.04-0.06 ms) of impact at low velocities, while regional break was observed at 0.14 ms after an impact at high velocity (75 m/s). In contrast, wound damage was observed in the lower quadrant of the suture zone and sclera in 12° up-gaze cases. Wound damage was observed 0.08 ms after an impact threatening corneoscleral laceration, and the involved area being larger in middle impact velocity (60 m/s) simulations than in lower impact velocity simulations, and larger damaged area was observed in high impact velocity cases and leading to corneoscleral laceration.

Conclusion

These results suggest that the eye is most susceptible to corneal damage around the suture area especially with a straight-gaze impact by an air gun, and that special precautionary measures should be considered in patients who undergo PKP. FEA using a human eyeball model might be a useful method to analyze and predict the mechanical features of eyes that undergo keratoplasty.

Hyperopic Shift after 4-8 Incision Radial Keratotomy: Eight-Year Follow-Up

PURPOSE

To evaluate the prevalence, amount and possible factors connected with the hyperopic shift after radial keratotomy.

BASIC PROCEDURES

We studied 86 eyes (51 patients) which underwent 4-8 incision radial keratotomy (delayed technique), consecutively performed by the same surgeon between February 1983 and November 1988. The diamond-bladed knife was set at 95% of the smallest paracentral ultrasonic corneal thickness measurement and the clear zone diameter was between 3.0 and 3.5 mm. Preoperative myopia ranged from -2.00 to -7.25 diopters (D). The average follow-up was 97.4 months (range 78 to 122 months).

MAIN FINDINGS

After eight years of follow-up, the cycloplegic spherical equivalent was satisfactory: 66.2% of the eyes showed a refractive error within 0.5 D, 17.4% were myopic by more than 0.5 D and 16.2% were hyperopic by more than 0.5 D. The mean refractive error was 0.02 D (SD +/- 0.75 D). Between six months and eight years after surgery a hyperopic shift of more than 0.5 D was found in 40.6% of the eyes. The mean hyperopic shift was higher (0.78 D) in the eyes which had keratometry less than 36 D six months after surgery. Compared to the eyes with keratometry greater than 36 D (mean hyperopic shift 0.38 D), the difference was statistically significant (p < 0.02).

CONCLUSIONS

These results show that keratometry, measured six months postoperatively, plays a fundamental role in the stability of postsurgical refraction, as the risk of hyperopic shift is higher in eyes with keratometry < 36 D.

Correction of hyperopia with astigmatism following radial keratotomy with daily disposable plus spherical contact lens: a case report

Purpose

To report the refractive correction in a case of hyperopia and astigmatism following radial keratotomy.

Methods

A case report.

Results

A 47-year-old woman, who had undergone refractive surgery for radial keratotomy in both eyes 22 years before the present study, presented to our clinic with blurred vision. Her best corrected visual acuity, with spectacle correction of +3.50 DS/−1.50 DCX130° in the right eye and +3.75 DS/−1.50 DCX80° in the left eye, was 0.2 logMAR and 0.3 logMAR, respectively. Her keratometric readings were 35.75 D/36.75 D at 74° and 35.25 D/36.25 D at 61°, respectively. Prompted by intolerance to glasses, the patient requested for contact lenses. First, we applied a rigid, gas-permeable contact lens. However, we noted poor fitting due to central corneal flattening. Subsequently, we applied a conventional plus spherical soft contact lens (PSSCL), which is thick in the center and can therefore correct hyperopia and low-grade astigmatism simultaneously. The conventional PSSCL showed slightly inferior decentration, with good movement, and the patient was satisfied with it. After ascertaining the patient’s living habits, we decided that a daily disposable soft contact lens would most meet her needs. The final prescription was a daily disposable PSSCL; the patient was satisfied with her corrected visual acuity of 0.0 logMAR in the right eye and 0.0 logMAR in left eye. Her daily disposable PSSCL-corrected visual acuity was stable during the 10-month follow-up.

Conclusion

For patients displaying hyperopia with astigmatism following radial keratotomy, the PSSCL may confer better corrected visual acuity and acceptability.

Clinical evaluation of the intraoperative refraction technique for intraocular lens power calculation

OBJECTIVE

To evaluate clinically the intraoperative refraction technique for intraocular lens (IOL) power calculation using 2 existing formulas proposed by Ianchulev and Leccisotti and to derive alternative formulas for this technique.

DESIGN

Comparative case series.

PARTICIPANTS

One hundred eighty-two eyes from 182 patients with cataract.

METHODS

Recruited patients were separated into a normal cornea group and a special group that included eyes with surgically altered corneas. Phacoemulsification was carried out for all cases. Intraoperative aphakic autorefraction using a portable autorefractor was performed. An IOL with power calculated before surgery then was implanted. In each eye, postoperative refraction was obtained. The IOL power that would have achieved emmetropia was calculated retrospectively. Aphakic autorefraction readings obtained during surgery were used to calculate the aphakic spherical equivalent (SE). The 2 formulas incorporating aphakic SE were applied to calculate the target IOL power. Comparison then was made to determine the accuracy of the formulas.

MAIN OUTCOME MEASURES

A difference (referred to as IOL difference) was calculated by subtracting the adjusted emmetropic IOL power determined by postoperative refraction from the emmetropic IOL power calculated by the 2 formulas using intraoperative aphakic SE.

RESULTS

One hundred forty-four patients were in the normal cornea group and 18 were in the special group. In the normal group, the Ianchulev formula showed a relatively accurate prediction for IOL power to achieve emmetropia over almost the full range of axial length except in extremely long eyes. The Leccisotti formula tended to overestimate IOL power and worked particularly poorly in short eyes. It worked best in long eyes. In the special group, neither of the 2 formulas was able to show superiority universally. Using data from the normal group, alternative formulas for IOL power calculation were derived. These new formulas then were validated on the special group that showed good estimation.

CONCLUSIONS

The Ianchulev formula could be applied to most eyes, with the exception of those in highly myopic subjects. The Leccisotti formula showed good performance in myopic patients. For eyes falling into the special group, an alternative formula, correction factor, or both, may be required. The new formulas reported herein may be an option.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Irregular astigmatism after cataract surgery resulting from inadequate clear corneal incision formation

A 66-year-old woman was referred to us due to visual complaints after cataract surgery. The patient's complaints were decreased visual acuity and a localized blur in her visual field. At slit lamp biomicroscopy, an unusually long and centrally located clear corneal incision was noted. Corneal topography revealed an irregular astigmatism in the optical axis, originating from the site of the incision. The patient's visual complaints were treated by fitting a rigid gas permeable contact lens, which increased her best corrected visual acuity to 20/16. This case report demonstrated that inadvertently long and centrally located corneal incisions should be avoided during cataract surgery to prevent high levels of irregular astigmatism. RGP contact lenses can lead to successful visual rehabilitation.

Traumatic epithelial downgrowth after radial keratotomy

A 40-year-old white man who had radial keratotomy (RK) in both eyes in 1993 experienced pain, extreme photophobia, and mild loss of uncorrected visual acuity in the right eye after being struck by a nail. The patient presented with a small, deep stromal lesion and was initially treated with a variety of antibiotic regimens without improvement in the lesion's appearance. Upon referral, confocal microscopy was performed and clearly demonstrated epithelial cells in the deep stroma and on the endothelial surface. After all medications were stopped, the mild symptoms resolved and the clinical appearance remained stable. Patients with RK incisions are at risk for traumatic epithelial downgrowth even many years after surgery. With confocal microscopy, epithelial downgrowth can be definitively diagnosed. Management of this condition remains controversial.

Pupil size and corneal laser surgery

PURPOSE OF REVIEW

The role of scotopic pupil size as a factor in predicting night vision complaints is controversial. This review summarizes reports in the literature, some that have found and some that have failed to find a correlation with scotopic pupil size and night vision complaints.

RECENT FINDINGS

Pupil-measuring devices are discussed along with informed consent issues and reports showing that wavefront aberrations increase with increasing pupil size. A new objective measuring device (Larson) showed a correlation with postoperative starbursts and pupil size and a decrease in starbursts with wavefront-guided treatments compared with conventional excimer laser treatments. Cortical adaptation allows many patients to adapt to their new night vision. Treatment options for those who remain symptomatic include drops to reduce pupil size and wavefront-guided retreatments.

SUMMARY

Reports in the literature are conflicting, and refractive surgeons would be wise to inform their patients that large scotopic pupil size is a potential risk factor for night vision complaints. By doing this they will follow the recommendations in recent patient information brochures of both VISX (Santa Clara, California) and Alcon (Orlando, Florida) and on the United States Food and Drug Administration web site.

A return to primitive practice? Radial keratotomy revisited

Recently, a refractive surgeon was quoted in the national and professional press as proposing that radial keratotomy (RK) is to be preferred over laser procedures, such as photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK). The rationale for this public recommendation was that the RK procedure achieves better visual results and fewer complications than the laser procedures. Peer reviewed literature on these refractive procedures was surveyed to establish the validity of such a statement and it was found that current data do not support the notion that RK results in better visual outcomes than PRK and LASIK The true incidence of complications is difficult to establish. However, when the post procedure chronic effects are compared between RK, PRK and LA SIK, it becomes apparent that the post-RK patient pays the highest price, by a large margin, in visual quality impairment and corneal health. Although the visual acuity outcomes for low to moderate myopes, when corrected by any of the three refractive procedures considered here, are not dramatically different, we concluded that RK is not the preferred methodology because of its associated chronic visual and corneal health complications.

Infectious Keratitis After Astigmatic Keratotomy in Penetrating Keratoplasty

PURPOSE

To present 3 cases in 2 patients of infectious keratitis of the astigmatic keratotomy (AK) site in patients who had previous penetrating keratoplasty.

METHODS

History, clinical examination, chart review, cultures, and laboratory results were obtained from 2 patients with infectious keratitis within the donor stroma of their graft after an AK was performed.

RESULTS

One patient had an early infiltrate of the AK site that was culture negative. This cleared with fortified antibiotics, and the patient had a final visual acuity of 20/30-2. The second patient developed 2 late infections, the first with coagulase negative Staphylococcus and the second infection with Pseudomonas aeruginosa. Both of these infections cleared with fortified antibiotics, and the final visual acuity was 20/25. Neither patient developed a rejection episode from the infections, and both grafts survived.

CONCLUSIONS

We report a series of 3 cases of infectious keratitis in 2 patients after AKs in corneal grafts. This, to the best of our knowledge, has not been previously reported. Patients who suffer infectious keratitis after AK in corneal grafts may have good visual outcomes if managed with appropriate antibiotic regimens and closely followed.

The effects of depowered airbags on eye injuries in frontal automobile crashes

The purpose of this study was to investigate eye injuries resulting from frontal automobile crashes and to determine the effects of depowered airbags. The National Automotive Sampling System database files from 1993 to 2000 were examined in a 3-part investigation of 22 236 individual crashes. Of the 2 103 308 occupants exposed to a full powered deployment, 3.7% sustained an eye injury compared to 1.7% of the 310 039 occupants exposed to a depowered airbag deployment. Occupants were at a significantly higher risk to sustain an airbag-induced eye injury when exposed to a full powered airbag compared with occupants exposed to a depowered airbag deployment ( P = .04). Approximately, 90% of the eye injuries in full powered airbag deployments were caused by the airbag, compared to only 35% of the depowered airbag eye injuries.

Rupture of Radial Keratotomy Incisions by Blunt Trauma 6 Years After Combined Photorefractive Keratectomy/Radial Keratotomy

PURPOSE

To report a case of traumatic corneal rupture that occurred 6 years previous, following combined radial keratotomy (RK) and photorefractive keratectomy (PRK).

METHODS

A 28-year-old man experienced a severe direct trauma to the right eye. Upon initial examination, a ruptured globe was diagnosed. Four of the eight radial incisions were ruptured with extrusion of intraocular tissues. The patient was also diagnosed with a fracture of the medial wall of the right orbit. The patient received immediate surgery during which the radial incisions that had been torn were stitched with a suture.

RESULTS

Following the postoperative period, the patient had visual acuity of light perception.

CONCLUSION

PRK, carried out on a cornea already treated with RK, may increase the likelihood of rupture in blunt trauma.

Combined laser in situ keratomileusis and radial keratotomy for the treatment of moderate to high myopia

PURPOSE

To evaluate the results of combining laser in situ keratomileusis (LASIK) and radial keratotomy (RK) for the correction of moderate to high myopia.

SETTING

Corneal Consultants of Colorado, Littleton, Colorado, and International Eye Care Laser Vision Center, Houston, Texas, USA.

METHODS

In a retrospective 2-surgeon interventional case series, outcomes in 60 eyes of 41 patients with moderate to high myopia were reported. All eyes had LASIK using a Visx Star S2 or Summit Apex Plus((R)) excimer laser. Residual myopia was treated with RK.

RESULTS

Of the 54 eyes corrected for distance, the mean refractive spherical equivalent was -8.09 diopters (D) preoperatively and -0.43 D after LASIK and RK. The mean follow-up was 15.4 months. At the last visit, the uncorrected visual acuity was 20/20 in 22 eyes (41%), 20/25 in 36 eyes (67%), and 20/40 in 51 eyes (94%). No eye lost 2 or more lines of best spectacle-corrected visual acuity.

CONCLUSIONS

Many patients previously considered poor refractive surgery candidates because of their degree of myopia or corneal thickness could be offered this safe and effective combined refractive technique.

Night vision disturbances after corneal refractive surgery

A certain percentage of patients complain of "glare" at night after undergoing a refractive surgical procedure. When patients speak of glare they are, technically, describing a decrease in quality of vision secondary to glare disability, decreased contrast sensitivity, and image degradations, or more succinctly, "night vision disturbances." The definitions, differences, and methods of measurement of such vision disturbances after refractive surgery are described in our article. In most cases of corneal refractive surgery, there is a significant increase in vision disturbances immediately following the procedure. The majority of patients improve between 6 months to 1 year post-surgery. The relation between pupil size and the optical clear zone are most important in minimizing these disturbances in RK. In PRK and LASIK, pupil size and the ablation diameter size and location are the major factors involved. Treatment options for disabling glare are also discussed. With the exponential increase of patients having refractive surgery, the increase of patients complaining of scotopic or mesopic vision disturbances may become a major public health issue in the near future. Currently, however, there are no gold-standard clinical tests available to measure glare disability, contrast sensitivity, or image degradations. Standardization is essential for objective measurement and follow-up to further our understanding of the effects of these surgeries on the optical system and thus, hopefully, allow for modification of our techniques to decrease or eliminate post-refractive vision disturbances.

Epithelial plugs in radial keratotomy: the origin of incisional keratitis?

PURPOSE

Incisions in radial keratotomy (RK) patients were examined histopathologically to explore the cause of delayed infections occurring following this procedure.

METHODS

Four corneas from two successful RK patients were obtained postmortem and 1 cornea from an unsuccessful RK was collected following lamellar keratoplasty. The tissue was prepared for light and transmission electron microscopy.

RESULTS

All incisions examined contained an epithelial plug. The average depth of the plugs for left and right corneas in the 2 successful cases were 142.58 microm (range: 36.46-183.04 microm) and 58.44 microm (range: 29.27-115.66 microm), whereas the unsuccessful case these measurements were 121.06 microm (range: 70.03-172.01 microm). In the successful cases, the plugs were on average 4.2 cells deep (range: 2-5) in one case and for the other the plugs were 8.78 cells deep (range: 1.5-11.5) and 2.72 cells wide (range: 2-4). In the unsuccessful case the plugs were on average 6.89 cells deep (range: 5-11) and 8.56 cells wide (range: 4-13). The average epithelial thickness, measured 200 microm on either side away from the plug, was 47.11 microm and 55.09 microm for the successful cases, and 27.52 microm for the unsuccessful case. Degenerate cells were often observed within the plug and along the overlying surface. Lamellae cut during surgery remained severed in all corneas observed. The stroma adjacent to the incision contained an elevated number of stromal cells (8%-78%).

CONCLUSIONS

Healing did not include repair of anterior limiting lamina or stromal lamellae, which all remained severed in all incisions observed. Epithelial plugs were invariably present in all incisions regardless of clinical outcome, thus, increasing the distance a basal cell travels to reach the epithelial surface by 2 to 4 times. Since the epithelial cell has a limited life, it is hypothesized that cells originating in the plug may die before reaching the surface, thus, leading to intermittent loss of surface integrity. The loss of the epithelial barrier allows invasion of microorganisms and the delayed onset of keratitis. The larger the plug the greater the possibility of surface defects and resultant infection.

Hyperopic laser in situ keratomileusis to treat overcorrected myopic LASIK

PURPOSE

To evaluate the safety and efficacy of hyperopic laser in situ keratomileusis (LASIK) in treating hyperopia caused by overcorrected myopic LASIK and to evaluate a new technique to place the hyperopic treatment after lifting the initial myopic flap.

SETTING

Open-access outpatient excimer laser surgical facility.

METHODS

A retrospective analysis was performed of 54 eyes in 47 patients who had spherical hyperopic LASIK by 21 surgeons for the treatment of significant hyperopia after overcorrected LASIK for myopia. In 42 eyes, the initial LASIK flaps were lifted and in 12 eyes, new flaps were cut. The mean age of the 25 men (53%) and 22 women (47%) was 48.2 years +/- 8.4 (SD). Outcome measures included refractive error, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications. The mean follow-up was 2.97 months.

RESULTS

In eyes in which postoperative emmetropia was attempted (n = 45), the mean spherical equivalent improved from +1.21 +/- 0.49 diopters (D) preoperatively to -0.38 +/- 0.50 D postoperatively (P <.001). The mean UCVA improved from 20/38.6 +/- 16.3 to 20/27.4 +/- 9.4 (P <.001). At the last follow-up, 69% of eyes were within +/-0.5 D and 96% were within +/-1.0 D of emmetropia; 42% had a UCVA of 20/20 and 96% had a UCVA of 20/40 or better. No eyes lost 2 or more lines of BSCVA. No vision-threatening complications occurred. Results in patients who had initial flaps lifted and those who had new flaps cut were statistically indistinguishable. On average, achieved hyperopic corrections were 18% greater than intended.

CONCLUSION

Hyperopic LASIK was safe, predictable, and effective in the treatment of hyperopia caused by overcorrected myopic LASIK. Results were similar whether the original flap was lifted or a new one was cut.

Comprehensive method of analyzing the results of photoastigmatic refractive keratectomy for the treatment of post-cataract myopic anisometropia

PURPOSE

To assess the efficacy, stability, and safety of photoastigmatic refractive keratectomy (PARK) in treating post-cataract myopic anisometropia to restore binocularity and to describe a comprehensive method for analyzing the results of refractive surgery.

SETTING

St. Paul's Eye Center, Royal Liverpool Hospital, Liverpool, United Kingdom.

METHODS

Nineteen patients (20 eyes) with post-cataract myopic anisometropia were treated with PARK using a VISX Twenty-Twenty laser and followed for 12 months. Cataract surgery had been performed between 10 and 144 months (mean 43.4 months) previously. A comprehensive method based on Long's matrix formalism and the vech operator of Harris, in addition to the nearest equivalent sphere and cylinder, was used to analyze the refractive data.

RESULTS

The mean preoperative refraction in the post-cataract eyes was -4.79 +1.17 x 0.2 and in the fellow eyes, +0.02 +0.31 x 166. Twelve months after PARK, the postoperative refraction in the post-cataract eyes was -0.90 +0.65 x 2, a significant reduction (P = .15). This postoperative refraction was not significantly different from that in the fellow eye (P = .93). The pretreatment mean uncorrected visual acuity was 0.12. It improved to 0.41 at 12 months, at which time 52% of eyes achieved a visual acuity of 0.5 or better without correction. All patients regained binocularity. At 12 months, 2 eyes (11%) showed clinically unacceptable regression; 1 eye with grade 2 haze lost 1 line of corrected visual acuity.

CONCLUSIONS

Photoastigmatic refractive keratectomy reduced post-cataract myopic anisometropia, allowing restoration of binocularity in all patients. Overall, the results in this elderly population with previous ocular surgery, posterior capsule thickening, and macular degeneration are not as satisfactory as those obtained from similar treatment of physiological myopia. Stability and postoperative complications are acceptable.

Recurrent anterior uveitis and glaucoma associated with inadvertent entry of ointment into the anterior chamber after radial keratotomy

Anterior uveitis and elevated intraocular pressure (IOP) occurred after radial keratotomy that was complicated by microperforation and penetration of antibiotic ophthalmic ointment into the anterior chamber. Anterior uveitis and IOP elevation were observed during the early postoperative follow-up and 41 and 61 months after surgery. All 3 attacks responded well to topical anti-inflammatory and antiglaucoma treatment. The probable causes of the uveitis and glaucoma in this case are discussed.

Early- versus late-onset infectious keratitis after radial and astigmatic keratotomy: clinical spectrum in a referral practice

PURPOSE

To compare the clinical characteristics of early- versus late-onset keratitis after radial keratotomy (RK) and astigmatic keratotomy (AK).

SETTING

Referral subspecialty practice.

METHODS

This retrospective review comprised 19 patients with infectious keratitis after RK and AK. Early- versus late-onset groups were analyzed for predisposing conditions; infiltrate location, size, and depth; microbiologic data; and final visual outcome.

RESULTS

Ten patients in the early-onset group developed keratitis within a mean of 7.4 days after surgery (range 3 to 14 days). Nine patients in the late-onset group developed keratitis a mean of 5.4 years after surgery (range 1.5 to 15.0 years). Staphylococcus aureus was the predominant organism in the early-onset group and Pseudomonas aeruginosa in the late-onset group. In the early-onset group, most infiltrates occurred in the paracentral aspect of the RK incision and extended to the middle or posterior stroma. In the late-onset group, most infiltrates occurred in the peripheral portion of the RK incision and were localized to the superficial stroma. A hypopyon was present in 7 of 10 ulcers in the early group and in 1 of 9 in the late group. Two patients in the early group developed endophthalmitis. Most patients in the late-onset group had incisional pseudocysts; 2 had other risk factors for keratitis. Final visual acuity was 20/40 or better in 7 of 10 patients in the early group and in 8 of 9 patients in the late group.

CONCLUSIONS

Early-onset corneal ulcers after incisional refractive keratotomy were usually paracentral and deep, whereas late-onset ulcers were usually peripheral and superficial. Despite the predominance of Staphylococcus and Pseudomonas in the early- and late-onset groups, respectively, a variety of organisms may be responsible for infections in keratotomy incisions.

Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy

Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A 56-year-old woman with mild dry-eye symptoms developed keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted for less than 1 day in the upper keratotomy incision. Corneal cultures yielded. Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the detection of keratitis. The inflammation was controlled with intravitreal, subconjunctival, topical, and systemic antibiotics. This case demonstrates the potential risk of endophthalmitis developing very shortly after late keratitis of AK incisions. Vigorous early treatment and close follow-up seem justifiable in any keratitis associated with a keratotomy incision.

Noncontact thermokeratoplasty to correct hyperopia induced by laser in situ keratomileusis

PURPOSE

To evaluate the efficacy and safety of noncontact holmium:YAG (Ho:YAG) laser thermokeratoplasty (LTK) for treating hyperopia induced by laser in situ keratomileusis (LASIK).

SETTING

Department of Ophthalmology, University of Alicante, Instituto Oftalmológico de Alicante, Alicante, Spain, and the University of Al-Azhar, Cairo, Egypt.

METHODS

Noncontact LTK was applied to 13 eyes (11 patients) with significant hyperopia after LASIK using a Ho:YAG laser (model gLase 210, Sunrise Technologies). Mean spherical equivalent before LTK was +4.60 diopters (D) +/- 1.40 (SD) (range +2.50 to +7.25 D). The results were evaluated 18 months after the LTK surgery.

RESULTS

A significant myopic shift developed in all eyes that gradually receded to emmetropia 6 to 8 weeks after LTK. After 12 months, refraction was relatively stable. At 18 months, there was a statistically significant difference between the mean uncorrected visual acuity (UCVA) before LTK (0.19 +/- 0.09) and mean postoperative UCVA (0.61 +/- 0.22) (P < .005). At the end of the study, there was a mean increase of 4.10 +/- 1.12 D in central keratometric power. Total regression did not occur in any eye.

CONCLUSION

Noncontact Ho:YAG LTK was safe and effective in correcting LASIK-induced hyperopia. The cutting of Bowman's layer and a thinner corneal center may contribute to the stability of LTK in such cases.

Surgical correction of moderate myopia: which method should you choose? I. Radial keratotomy will always have a place

This set of "Viewpoints" articles examines the relative merits of radial keratotomy (RK), photorefractive keratectomy (PRK), and laser assisted in-situ keratomileusis (LASIK). Drs. Rowsey and Morley review advances in RK techniques, long-term results, and complications, and explain why RK will remain a viable method for correction of moderate myopia, notably its minimal cost. Drs. Steinert and Bafna review both PRK and LASIK, discussing techniques and results and comparing their advantages and disadvantages with each other and with RK. Dr. Dutton, as "Viewpoints" section editor, summarizes clinical, technologic, and economic aspects of all three techniques, concluding that all will find a place among refractive surgeons for some time to come.

Minoxidil-induced alteration of corneal topography after radial keratotomy

PURPOSE

To determine the antiproliferative effect of minoxidil on human corneal epithelium (hCE) proliferation in vitro and to assess whether topical minoxidil can significantly alter corneal topography after radial keratotomy (RK) by inhibiting myofibroblast activity in the keratotomy wound.

SETTING

Corneal Research Laboratory, University of Chicago, Illinois, USA.

METHODS

In the in vitro evaluation, proliferating hCE was exposed to minoxidil (0.1 to 2.0 mM) for 96 hours to determine the minimum inhibitory dose. Human corneal epithelium cell proliferation was assessed by the incorporation of bromodeoxyuridine (BRDU) into DNA. In the in vivo analysis, eight New Zealand albino rabbits had an eight-incision bidirectional RK on one eye and were divided into two groups. The control eyes (n = 3) received tobramycin and dexamethasone (TobraDex), ciprofloxacin hydrochloride (Ciloxan), and balanced salt solution (BSS) drops four times a day for 3 weeks, while the treatment eyes (n = 5) received TobraDex, Ciloxan, and minoxidil 1.0 mM drops four times daily for 3 weeks. The net change in corneal curvature at 3 weeks was analyzed with corneal topography. Myofibroblast activity in the keratotomy wound was assessed using alpha smooth muscle actin staining techniques.

RESULTS

At concentrations of 1.0 mM and above, minoxidil caused a statistically significant, dose-dependent reduction in hCE cellular proliferation ranging from 29 to 44% (P < .05). Minoxidil (1.0 mM) caused a statistically significant central corneal flattening effect of 4.66 diopters (D) after RK in the treatment eyes compared with 1.11 D in the control eyes (P = .05). Histologically, minoxidil-treated keratotomy wounds lacked cells with contractile elements consistent with myofibroblast differentiation. Corneal epithelial wound healing was similar in both groups.

CONCLUSION

At the appropriate dose, topical minoxidil may be a useful adjunctive treatment that can reduce the number of undercorrections after mini-RK without apparent toxicity to the corneal epithelium.

Radial keratotomy for residual myopia after photorefractive keratectomy

PURPOSE

To evaluate the safety, efficacy, and complications of radial keratotomy (RK) after photorefractive keratectomy (PRK) for myopia.

SETTING

Laser Ultravision Institute. Montreal, Canada.

METHODS

Surgically induced refractive and visual acuity changes were retrospectively evaluated in 14 eyes of 10 patients treated with RK after PRK. All patients had simple myopia or compound myopic astigmatism. Minimum follow-up was 6 months.

RESULTS

Three eyes (21%) had one PRK, 7 (50%) had two treatments, and 4 (29%) had three. Eleven eyes (79%) required four-incision RK and 3 (21%), eight-incision RK. All patients had improved uncorrected visual acuity. Six months after the RK retreatment, there was a significant reduction in spherical equivalent of 2.93 diopters +/- 1.53 (SD) (P < .05). No intraoperative or postoperative complications occurred except overcorrection (two cases).

CONCLUSION

Radial keratotomy is an effective, safe method for treating undercorrected myopia after PRK. Further study and analysis of this series of patients are planned.

Dehiscence of a radial keratotomy incision during clear corneal cataract surgery

We report a case of dehiscence of a radial keratotomy (RK) incision caused by clear corneal cataract surgery. The patient had eight-incision RK in both eyes 9 months previously with enhancement surgery in the left eye 1 month later. Cataract surgery through a clear corneal incision was performed in the right eye and 1 month later, in the left. Surgery in the right eye was uneventful. However, during surgery in the left eye, dehiscence of one radial incision occurred. The wound dehiscence was closed with interrupted sutures, and the patient achieved 20/20, uncorrected visual acuity 1 week after surgery.

Photodynamic biologic tissue glue to enhance corneal wound healing after radial keratotomy

PURPOSE

To evaluate the effect of photodynamic biologic tissue glue (PBTG) on corneal wound healing after radial keratotomy (RK).

SETTING

Cornea Research Laboratory, The University of Chicago, Chicago, Illinois, USA.

METHODS

Bidirectional, eight-incision RK was done in one eye of eight Dutch pigmented rabbits. Then, PBTG was inserted into the RK incisions and activated with an argon blue-green laser in four treatment eyes. The rabbits were divided into three groups: early, in which corneal wound healing was assessed at 1 and 3 weeks; late, in which corneal wound healing was assessed at 8 weeks; enhancement.

RESULTS

The PBTG-treated keratotomy wounds had a more prominent epithelial healing response immediately after RK and a decreased propensity for wound dehiscence. Collagen fiber arrangement in the PBTG-treated incisions was sagittal to the keratotomy wound 1 to 3 weeks after RK and then changed to a transverse orientation across the keratotomy wound by 8 weeks. The control keratotomy wounds had a less prominent epithelial healing response and developed late disorganization of the posterior keratotomy wound at 8 weeks. Keratometry measurements 2 months after RK showed corneal flattening of 1.0 diopter (D) in the PBTG-treated eye and 6.5 D in the control eye, which is consistent with histologic studies showing more advanced wound healing in the PBTG-treated eyes. After RK enhancement, the PBTG-treated eye resisted further corneal flattening and had 4.5 D of corneal steepening; the control eye had 2.0 D of additional corneal flattening.

CONCLUSION

The nontoxic, laser-activated adhesive PBTG accelerated corneal wound healing after RK and simulated the placement of sutures into the RK wound. Thus, PBTG may be an alternative to sutures to correct hyperopia after RK in humans.

Etiology of ptosis after cataract surgery

PURPOSE

To determine whether using a lid speculum with a superior rectus bridle suture in cataract surgery results in levator rectus aponeurosis dehiscence caused by strong fascial attachments between the levator and superior rectus muscles.

SETTING

L.V. Prasad Eye Institute, Hyderabad, India.

METHODS

This study comprised 220 patients having cataract extraction with posterior chamber intraocular lens implantation. The patients were randomly assigned to one of two groups. In the first group (n = 108), a lid speculum was used during surgery. In the second group (n = 112), no speculum was used. All patients had a superior rectus bridle suture. The occurrence of ptosis was analyzed by a masked observer who was not involved in the surgery.

RESULTS

The incidence of ptosis was significantly higher in the speculum (44.4%) than in the no-speculum (23.3%) group (P = .0009).

CONCLUSION

The results indicate that the opposing forces created by the lid speculum and bridle suture can cause levator aponeurosis dehiscence because of the strong fascial attachments between the superior rectus and levator muscles. The occurrence of ptosis in the no-speculum group implies a multifactorial etiology, however.

Refractive outcome following radial keratotomy and combined radial and astigmatic keratotomy

PURPOSE

To determine whether the visual and refractive outcomes of combined astigmatic and radial keratotomy (AK/RK) procedures was different from that following RK for the correction of naturally occurring compound myopic astigmatism and spherical myopia.

SETTING

Private professional practice, San Diego, California, USA.

METHODS

The computer database of all incisional procedures performed by one surgeon over 10 years was reviewed to compare the visual acuity outcome of AK/RK and RK procedures. Enhancement procedures were excluded. Only data from the last office visits were analyzed to establish the relationship between visual acuity and type of keratotomy procedure performed. A multiple regression model was constructed, which included covariates of age, postoperative keratometric cylinder, and postoperative refraction.

RESULTS

After controlling for covariates, the AK/RK population had significantly lower postoperative uncorrected visual acuity levels than the RK population (P < .03) after one operation (prior to enhancement surgery).

CONCLUSIONS

Using the nomograms for myopia correction for unenhanced RK cases, combined AK and RK procedures appeared to reduce the expected visual results. Surgeons may consider modifying surgical nomograms to account for the expected spherical undercorrection that can occur when myopia and astigmatism are corrected simultaneously.

Delayed microbial keratitis following radial keratotomy

BACKGROUND

We report on the case of a 46-year-old female who presented with delayed microbial keratitis 10 years after uncomplicated radial keratotomy.

METHODS

The pre- and postoperative clinical record was reviewed following her presentation to the Corneal Clinic. Slit-lamp examination revealed a stromal inflammatory infiltrate at the site of an earlier radial keratotomy incision. The lesion was scraped and a coagulase-negative Staphylococcus aureus was cultured in enrichment broth.

RESULTS

The keratitis was treated successfully with combination fortified topical antibiotics without loss of vision.

CONCLUSIONS

Although microbial keratitis is a well documented complication of incisional refractive procedures, it is rarely encountered as late as one decade after surgery. Patients should be warned of this possibility and the need for prompt treatment.

Endophthalmitis after radial keratotomy enhancement

A 45-year-old man developed endophthalmitis after a radial keratotomy (RK) enhancement. He developed severe intraocular inflammation, hypopyon, and dense vitreous membranes 4 days after the enhancement surgery. Cultures of the corneal wound yielded a heavy growth of Streptococcus viridans. The inflammation subsided after treatment with intraocular, intravenous, and topical antibiotics. The patient subsequently developed a cataract and retinal detachment. This case demonstrates the risk of endophthalmitis after RK enhancement.

Correcting postoperative astigmatism using curved lamellating keratotomy

PURPOSE

To ascertain whether the change in refraction caused by paired lamellating corneal incisions in cadaver eyes could be achieved in living eyes and whether wound healing influences this effect.

SETTING

Virchow Hospital Eye Clinic, Humboldt University, Berlin, Germany.

METHODS

This prospective study included 45 patients who had a follow-up of 15 months. All had astigmatism of at least 2.00 diopters (D) induced by previous cataract surgery. Optical zones of 7.0 and 8.0 mm and chordal lengths of 3.0 and 5.0 mm were used. All incisions were paired.

RESULTS

Mean preoperative astigmatism measured with a keratometer was 3.64 D +/- 0.89 (SD). After 15 months, it was 1.00 +/- 0.76 D, and mean induced astigmatism was 3.18 +/- 1.30 D. The 7.0 mm group had a mean induced astigmatism of 3.93 +/- 1.52 D, which was significantly higher than that in the 8.0 mm group (mean 2.60 +/- 0.74 D) at a uniform chordal length of 3.0 mm. Mean uncorrected visual acuity was 0.26 +/- 0.14 preoperatively and 0.50 +/- 0.28 after 15 months; mean corrected visual acuity improved from 0.58 +/- 0.21 to 0.76 +/- 0.21. Mean endothelial cell count was 1799 +/- 595 cells/mm2 preoperatively and 1784 +/- 589 cells/mm2 after 6 months; the difference was not significant.

CONCLUSION

Curved lamellating keratotomy gives stable postoperative refractive results without significantly affecting endothelial cell count or visual acuity.

Correction of Hyperopia Induced by Photorefractive Keratectomy Using Non-contact Ho:YAG Laser Thermal Keratoplasty

PURPOSE

To evaluate the safety and effectiveness of non-contact holmium:YAG laser thermal keratoplasty in correcting hyperopia induced by photorefractive keratectomy (PRK).

METHODS

Non-contact holmium:YAG laser thermal keratoplasty was applied to 14 eyes with significant hyperopia induced by PRK. The mean spherical equivalent refraction before holmium:YAG laser thermal keratoplasty was +4.20 +/- 1.80 diopters (D) (range, +1.75 to +6.25 D). The results were evaluated 12 months after holmium:YAG laser thermal keratoplasty.

RESULTS

No sight-threatening complications occurred. Recovery of spectacle-corrected visual acuity took from 2 to 6 weeks. The immediate significant myopic shift that developed in all eyes gradually receded over 6 to 8 weeks. All eyes were relatively stable after 9 months. At 12 months, there was no statistically significant difference (p < .005) between the mean preoperative spectacle-corrected visual acuity (0.71 +/- 0.12) and the mean postoperative uncorrected visual acuity (0.65 +/- 0.28). At 12 months there was a mean increase of 4.60 +/- 1.20 D in central keratometric power. Total regression did not occur in any eye.

CONCLUSIONS

Non-contact holmium:YAG laser thermal keratoplasty offers a safe and effective alternative to correct PRK-induced hyperopia.

Photorefractive Keratectomy Following Radial Keratotomy

BACKGROUND

Excimer laser photorefractive keratectomy (PRK) has been used to correct residual myopia in eyes that have had refractive keratotomy.

METHODS

Nine eyes of eight patients were studied at a mean of 13 months after PRK. Previous procedures included radial keratotomy (9 eyes) and myopic keratomileusis (1 eye). PRK was performed using a Summit Technology excimer laser with a 5.0-mm diameter ablation zone.

RESULTS

Uncorrected visual acuity improved in 7 of 9 eyes. The refractive outcome was within 1.00 diopter (D) of attempted correction for 3 of 9 eyes. Spectacle-corrected visual acuity decreased 2 or more Snellen lines in 2 of 9 eyes. Subepithelial corneal stromal haze was seen 1 month postoperatively in 6 of 8 eyes and was present in 4 of 6 eyes at 1 year. Stromal haze was associated with regression of the refractive effect of the PRK.

CONCLUSIONS

PRK in eyes with previous radial keratotomy appears to be less predictable and may be associated with greater corneal haze and regression of refractive correction than in previously unoperated eyes. Activation of stromal fibroblasts in the previous corneal incisions may cause these findings.

Cyanoacrylate glue treatment for persistent aqueous leak following postkeratoplasty relaxing incisions with compression sutures

In spite of improvements in surgical techniques, donor materials and postoperative care, high astigmatism remains a quite common problem following penetrating keratoplasty [1]. Whenever the residual astigmatism cannot be corrected with spectacles or contact lenses, surgical treatment is required. Relaxing incisions combined with compression sutures is one of the most common methods used for this purpose [2, 3]. We report herein a case of persistent aqueous leak following relaxing incisions for the correction of postkeratoplasty astigmatism. The leak failed to respond to a bandage contact lens and resuturing and was eventually successfully treated with the use of cyanoacrylate glue. A marked regression of the surgical effect was observed in this case.

Eye Infections After Refractive Keratotomy

BACKGROUND

Ocular infections are serious and potentially vision-threatening complications of refractive keratotomy. We have performed an integrative review of published literature to address important issues concerning these complications.

METHODS

Articles in MEDLINE and published manuscripts and abstracts reporting previously unpublished cases of infections after refractive keratotomy were systematically identified and reviewed. Our review did not target patients treated with relaxing incisions for postkeratoplasty astigmatism. Pertinent data were abstracted and analyzed.

RESULTS

Forty-three cases (47 episodes: 42 keratitis and 5 endophthalmitis) of infection appeared in 26 published reports from 1975 to 1994. The frequency ranged from 0.25% to 0.70%. In 22 (47%) eyes, infection occurred before 2 weeks. Thirty-five (74%) infections were located in the inferior half of the cornea, and 22 (62%) were located in the inferotemporal quadrant. Thirty-one (66%) infections were bacterial (32% gram-positive, 23% gram-negative, 9% acid fast, 496 unknown), 5% fungal, 6% viral, 19% sterile, and 4% of unknown origin. Spectacle-corrected visual acuity after conservative treatment was 20/40 or better in 70% of eyes. Penetrating keratoplasty was performed in six cases. Potential associations included reoperations in 12 (26%) eyes, postoperative contact lens wear in 7 (15%), and intraoperative perforation in 7 (15%).

CONCLUSIONS

The published literature indicates that infections after refractive keratotomy may compromise visual function. Approximately half of the infections occur in the first 2 weeks. Reoperations, postoperative contact lens wear, and intraoperative perforations may be significant risk factors.

Endophthalmitis and orbital cellulitis after radial keratotomy

PURPOSE

To report the findings concerning three patients with endophthalmitis and one with panophthalmitis and orbital cellulitis radial keratotomy surgery.

METHODS

One man referred with panophthalmitis and orbital cellulitis and three women referred with endophthalmitis were treated.

RESULTS

After radial keratotomy surgery, during which no microperforation or macroperforation had been reported, a severe Pseudomonas panophthalmitis and orbital cellulitis developed in the man. All vision was lost in that eye. Staphylococcus epidermidis endophthalmitis developed in one woman, Streptococcus pneumoniae endophthalmitis in the second woman and Pseudomonas endophthalmitis in the third woman, after undergoing radial keratotomy procedures during which microperforations occurred. In the latter patient, bilateral simultaneous surgery was performed, but only one eye became infected. The latter two infections resulted in light perception and hand motion vision respectively. In three cases, an initial keratitis was located in the inferior cornea.

CONCLUSIONS

Severe bacterial endophthalmitis can occur after radial keratotomy surgery, even in the absence of microperforation during the procedure. Any evidence of postoperative keratitis must be regarded seriously and treated aggressively. Despite use of this approach, the effect on final visual acuity can be devastating.