Proposed mechanism for retinal tears after LASIK

Assessment of the biometric modifications of the eye in LASIK during suction

PURPOSE

To study the biometric modifications of the eyeball during suction in Laser assisted in Situ Keratomileusis (LASIK).

METHODS

Observational and cross-sectional study. We studied 43 patients who underwent surgery for myopia and myopic astigmatism. Mean age was 38.3 ± 11.5 years, and 19 were female (44.2%). Conventional LASIK surgery with a manual microkeratome was performed. Before and during the suction maneuvre the following parameters were measured using an 11 Mhz biometric probe: aqueous depth (AQD), lens thickness (LT), vitreous cavity length (VCL) and axial length (AXL). Paired t-test was used to compare the biometric measurements before and during suction.

RESULTS

The mean spherical equivalent refractive error was -4.5 ± 2.3 diopters. During suction, the AQD did not change significantly (p = 0.231). However, AXL and VCL increased by 0.12 mm and 0.22 mm respectively (p = 0.039 and <0.01) and LT decreased by 0.20 mm (p < 0.01). AXL increased in 42% of the eyes and decreased in 16%, VCL increased in 70% of the eyes and decreased in 9%, and the LT was reduced in 67% of the eyes.

CONCLUSIONS

Suction maneuvres during LASIK surgery produce changes of little magnitude in the eye globe, mainly a decrease in LT and an increase in VCL and AXL. Therefore, these modifications are expected to produce minimal anatomic alterations.

Controversies and Disparities in the Management of Age-Related Macular Degeneration

Age-related macular degeneration is a leading cause of blindness in patients aged 50 years and older. Prior to the 21^st century, there were no effective treatments for this devastating disease. However, the last 20 years have heralded the development of treatments for both the nonexudative and exudative forms. The invention of AREDS vitamin supplements and anti-VEGF therapies forever changed the treatment of dry and wet age-related macular degeneration, respectively. The rapid adoption and expansion of these vision preserving treatments has created controversy regarding their cost, burden of administration, development, and use of new technologies, genetic considerations, and observed societal disparities. Many of these controversies and disparities persist today and will require further research to resolve.

Changes in Retinal Vessel Flow after Small Incision Lenticule Extraction

Objective

In order to analyze changes in retinal vessel flow after small incision lenticule extraction (SMILE).

Methods

A total of 32 patients (62 eyes) who underwent SMILE were enrolled in this prospective study. Optical parameters, including vessel density (VD), and perfusion density (PD) of foveal, parafoveal, and perifoveal regions, respectively, were measured before surgery and at 1 day, 1 week, 1 month, and 3 months postoperation. Preoperative parameters and surgical parameters were recorded.

Results

Significant decreases in VD and PD on postoperative day 1 were detected in all quadrants, both in 3 mm and in 6 mm regions (P < 0.001). One month after surgery, VD returned to preoperative levels. None of the preoperative and surgical parameters were significantly correlated with the VD and PD fluctuations (all P > 0.05). Conclusion. VD may decrease significantly with regional disparity 1 day after SMILE while recovering at 1 month. Elevation of intraocular pressure due to suction may account for such changes.

Options and results in managing suction loss during small-incision lenticule extraction

Suction loss is an intraoperative complication in small-incision lenticule extraction (SMILE) that presents a management challenge for the refractive surgeon. The purpose of this review is to evaluate the visual, refractive, and wavefront outcomes after suction loss across the different stages of SMILE with various respective surgical treatments. Surgical management options include immediate re-SMILE by redocking or delayed re-SMILE, with or without adjustment of the laser parameters, conversion to femtosecond laser in situ keratomileusis, transepithelial photorefractive keratectomy, refractive lenticule extraction, or pseudo-SMILE. The restart treatment module on VisuMax provides appropriate retreatment recommendation. Most retreatment options for suction loss, immediate or delayed, resulted in effective, safe, and predictable outcomes, and patients were satisfied with their outcomes. Based on available level II evidence, immediate re-SMILE with or without adjustment to the laser settings achieve favorable visual and refractive outcomes in handling this intraoperative complication across all stages of SMILE.

Femtosecond-Laser Assisted Surgery of the Eye: Overview and Impact of the Low-Energy Concept

This article provides an overview of both established and innovative applications of femtosecond (fs)-laser-assisted surgical techniques in ophthalmology. Fs-laser technology is unique because it allows cutting tissue at very high precision inside the eye. Fs lasers are mainly used for surgery of the human cornea and lens. New areas of application in ophthalmology are on the horizon. The latest improvement is the high pulse frequency, low-energy concept; by enlarging the numerical aperture of the focusing optics, the pulse energy threshold for optical breakdown decreases, and cutting with practically no side effects is enabled.

First Experience in Small Incision Lenticule Extraction with the Femto LDV Z8 and Lenticule Evaluation Using Scanning Electron Microscopy

Purpose

To evaluate the specifications and technique properties of the new Femto LDV Z8 in creating intrastromal refractive lenticules during small incision lenticule extraction (SMILE).

Methods

Six enucleated porcine eyeballs were equally divided into two groups (Femto LDV Z8 or VisuMax) and were randomly assigned to three experienced refractive surgeons who performed SMILE on each group. Five intraoperative time parameters and surgeons' satisfaction on the surgical procedure were compared between two groups. Postoperatively, the roughness of the lenticule surfaces and the irregularity of edges were observed by scanning electron microscopy (SEM) and were also compared between the two groups.

Results

Longer time on suction peak pressure, total laser application, and total surgery were spent in the Femto LDV Z8 group as compared with the VisuMax group. The Femto LDV Z8 group applied OCT scanning and offsetting before performing the laser procedure, which expended more time for these crucial steps. The widest range of surgeons' satisfaction scores was found in the step of lenticule interface identification of the Femto LDV Z8 group. The roughness scores of the anterior and posterior lenticule surfaces were statistically less in the Femto LDV Z8 group than in the VisuMax group (anterior, ×180, p=0.039; anterior, ×250, p=0.337; posterior, ×180, p=0.006; and posterior, ×250, p=0.007).

Conclusions

Femto LDV Z8 showed promising performances as a novel SMILE equipment for the correction of myopia. It has special and unique features for SMILE procedures, which need more learning and researching processes. With its low-energy high-frequency nJ-level laser system, the Femto LDV Z8 provided smoother lenticule surface than VisuMax.

Changes in Retinal Vasculature and Thickness after Small Incision Lenticule Extraction with Optical Coherence Tomography Angiography

Purpose

To evaluate the changes in retinal vessel density and thickness after small incision lenticule extraction (SMILE) with optical coherence tomography angiography (OCTA) in myopic patients.

Methods

In this prospective study, SMILE surgeries were done in 46 eyes of 24 patients with spherical equivalent (SE) more than −6.0 diopters (D). Retinal vessel density and thickness at the macula and optic nerve were recorded with OCTA before and 1 day, 2 weeks, and 1 month after surgery. Intraocular pressure (IOP), uncorrected distance visual acuity (UDVA), and refraction were taken at the same time.

Results

The superficial retinal vessel density and deep foveal retinal vessel density 1 day after surgery were less than those before surgery; however, the changes at any timepoints were not statistically significant (p=0.2736 and p=0.1590, respectively). Both the superficial vessel density and deep vessel density at the parafoveal and perifoveal regions decreased significantly 1 day postoperatively (all p < 0.05) and then returned to the preoperative level at 2 weeks and stabilized thereafter. There were no significant changes in any of the 4 vessel densities in the area of peripapillary before and 1 day, 2 weeks, and 1 month after surgery (p=0.3345). No statistically significant differences between preoperative and postoperative retinal thickness were detected for the area of macula and optic nerve (all p > 0.5).

Conclusions

The vessel density at the parafoveal and perifoveal regions decreased at 1 day after SMILE with no effect on the visual acuity and relieved within 2 weeks. Decreased ocular blood flow in response to the spike in IOP may account for such changes.

Real-Time Intraocular Pressure Measurements in the Vitreous Chamber of Rabbit Eyes During Small Incision Lenticule Extraction (SMILE)

PURPOSE

To investigate real-time intraocular pressure (IOP) during small incision lenticule extraction (SMILE) in rabbit eyes for myopia correction.

METHODS

During SMILE, real-time IOP was measured in the vitreous cavity of rabbit eyes with an optic fiber pressure sensor (OFPS). Two groups (n = 6 for each) underwent surgery, one group for a -2.00 diopter (D) refractive spherical correction and the other for a -6.00 D correction.

RESULTS

During surgery, the IOP increased once the glass contact attached to the cornea (Pre-suction), and peaked 83.94 mmHg (SD ± 23.87 mmHg) for the -2.00 D group and 89.17 mmHg (SD ± 22.66 mmHg) for the -6.00 D group, both average values were less than 110 mmHg when suction was initiated to fix the glass contact onto the cornea (Suction on). It then fell to 74.81 mmHg (SD ± 20.64 mmHg) and 76.94 mmHg (SD ± 27.43 mmHg), respectively, and remained stable during lenticule creation (Cutting). After suction stopped (Suction off), IOP fell steeply. During lenticule separation/extraction, the change in IOP was 32.26 mmHg (SD ± 2.91 mmHg). Notably, the average duration of elevated IOP during the surgery was 166.05 s (no longer than 3 min).

CONCLUSIONS

The IOP fluctuations in the vitreous cavity using an OFPS in a rabbit model during SMILE showed that real-time IOP significantly was increased during Pre-suction, Suction on, Cutting, Suction off, and lenticule separation/extraction compared to baseline IOP, although, peaked at Suction on. Neither the degree of myopic correction nor central corneal thickness significantly affected these changes in IOP.

Outcomes of Vitreoretinal Surgery for Retinal Detachment after LASIK for Myopia

PURPOSE

To report and compare outcomes of vitreoretinal surgery for repair of retinal detachment in myopic patients with and without previous laser-assisted in situ keratomileusis (LASIK).

METHODS

This is a descriptive retrospective observational study with a control group for comparison that consisted of the analysis of clinical and surgical charts of patients who underwent vitreoretinal procedures for retinal detachment at the Fundación Oftalmologica Nacional between January 1995 and December 2002. The authors identified those myopic patients who had previous history of LASIK and an age- and myopia-matched control group without refractive surgery.

RESULTS

The sample contains 24 myopic eyes of 22 patients with previous LASIK and 23 myopic eyes without previous LASIK in the control group, matched by age and myopia. Mean refractive error was -9.4 D before LASIK for the cases group and -11.2 for the control group. Poor preoperative best-corrected visual acuity was present in 71% of cases and 61% of controls (p=0.489). Macula off retinal detachment was found in 17 eyes in both groups. Five eyes required at least two procedures, achieving 91% (20 eyes) reattachments at the end of follow-up in each group. Final best-corrected visual acuity was better than 20/100 in 15 eyes (62.5%) in the LASIK group and 17 eyes (74 %) in the control group (p=0.659).

CONCLUSIONS

Retinal detachment in patients with previous myopic LASIK has similar characteristics as in myopic patients without refractive surgery. Current vitreoretinal surgery is of good prognosis as the retina was successfully reattached in most cases in both groups.

Bilateral Simultaneous Rhegmatogenous Retinal Detachment following Laser in situ Keratomileusis

A 21-year-old woman developed simultaneous rhegmatogenous retinal detachment after laser in situ keratomileusis (LASIK) in both eyes. She underwent pars plana vitrectomy surgery combined with endolaser photocoagulation and silicone oil tamponade in the right eye. A week later, pneumatic retinopexy was done in the left eye. As the retinal tear did not seal, 360° scleral buckling surgery was performed and retina was attached. Bilateral simultaneous rhegmatogenous retinal detachment after LASIK for correction of myopia can be a serious complication. Patients should be informed about the possibility of this complication.

Characteristics of rhegmatogenous retinal detachment after refractive surgery: comparison with myopic eyes with retinal detachment

PURPOSE

To evaluate the characteristics of rhegmatogenous retinal detachment (RD) in patients with previous laser in situ keratomileusis (LASIK) and compare them to RD in patients with previous laser assisted subepithelial keratomileusis (LASEK) and myopic patients with no previous refractive surgery.

DESIGN

Retrospective, comparative case series.

METHODS

In 106 eyes of 106 patients with RD, patients with previous refractive surgery included 21 eyes after LASIK and 13 eyes after LASEK; 72 myopic patients with refractive errors of -3.0 diopters or less were grouped as the R (-) group. Characteristics of RD included distribution of RD and associated retinal breaks, location and number of retinal breaks, presence of lattice degeneration, and axial lengths.

RESULTS

The mean interval between refractive surgery and the onset of rhegmatogenous RD was 63.7 ± 43.5 months, occurring across a broad spectrum of time intervals. There were no significant differences among the LASIK group, the LASEK group, and the R (-) group in axial length (26.8 mm vs 26.4 mm vs 26.9 mm, respectively); in mean number of retinal holes/tears, (2.1/1.5, 0.9/1.4, 1.5/1.6, respectively); or in the presence of lattice degeneration (52.4% vs 46.2% vs 43.1%, respectively). Distribution of RD and associated retinal breaks were also not significantly different; retinal holes and tears were more prevalent in the temporal quadrants, and inferotemporal quadrants were the most commonly detached areas in both the LASEK and LASIK groups and in the R (-) group.

CONCLUSIONS

Myopia is a well-known risk factor for rhegmatogenous RD and may contribute more to the development of RD in myopic patients after refractive surgery, rather than refractive surgery itself.

Intraocular pressure measurements during flap preparation using 2 femtosecond lasers and 1 microkeratome in human donor eyes

PURPOSE

To evaluate and compare intraocular pressures (IOPs) during flap preparations performed using 2 femtosecond lasers and a mechanical microkeratome in human donor globes.

SETTING

University Medical Center Mainz, Mainz, and Euroeyes Clinic Stuttgart, Stuttgart, Germany.

DESIGN

Experimental study.

METHODS

A cannula was inserted through the optic nerve in human globes. The IOP was obtained continuously during flap preparation using the 60 kHz Intralase femtosecond laser, the 200 kHz Visumax femtosecond laser, or the Amadeus II microkeratome. For each experiment, a normal lamellar flap preparation (regular procedure) and a worst-case procedure (femtosecond laser interface was pressed against globe until docking maneuver was aborted) were performed.

RESULTS

During the regular procedure, the mean maximum IOP measured was 181.3 mm Hg (range 159.1 to 194.8 mm Hg) with the 60 kHz femtosecond laser, 77.6 mm Hg (range 58.1 to 100.3 mm Hg) with the 200 kHz femtosecond laser, and 198.1 mm Hg (range 162.8 to 299.6 mm Hg) with the microkeratome. During the worst-case procedure, the maximum measured IOP was 319.7 mm Hg (range 299.1 to 341.2 mm Hg) with the 60 kHz laser and 120.4 mm Hg (range 118.1 to 134.7 mm Hg) with the 200 kHz laser.

CONCLUSION

Maximum IOPs during corneal flap preparations in human enucleated eyes were lower during performance of a regular procedure and a worst-case procedure with the 200 kHz femtosecond laser than with the 60 kHz femtosecond laser and the mechanical microkeratome.

FINANCIAL DISCLOSURE

Dr. Sekundo is a member of the Scientific Advisory Board of Carl Zeiss Meditec AG, Jena, Germany. No author has a financial or proprietary interest in any material or method mentioned.

Retinal detachment after laser in situ keratomileusis

Purpose:

To report characteristics and outcome of rhegmatogenous retinal detachment (RRD) after laser in situ keratomileusis (LASIK) for myopia.

Materials and Methods:

A retrospective chart review of patients who presented with RRD after myopic LASIK over a 10-year period.

Results:

Fourteen eyes were identified with RRD. Of these, two of 6112 LASIK procedures were from our center. The mean age of patients with RRD was 35.43 years. The mean interval of RRD after LASIK was 37.71 months (range, 4 months to 10 years). The macula was involved in eight eyes and spared in six eyes. Retinal breaks included a macular hole in two eyes, and giant tear in two eyes. Multiple breaks (>2 breaks) occurred in 6 cases. Pars plana vitrectomy (PPV) was performed in 3 (21.4%) eyes, a scleral buckle (SB) was performed in 4 (28.5%) eyes and 7 (50%) eyes underwent combined PPV and SB. Mean follow-up was 15.18 months (range, 1 month to 7 years). The retina was successfully attached in all cases. The final visual acuity was 20/40 or better in 7 (50%) eyes, 20/40 to 20/60 in 4 (28.5%) eyes, and 20/200 or less in 3 (21.4%) eyes. Poor visual outcome was secondary to proliferative vitreoretinopathy, epiretinal membrane, macular scar and amblyopia.

Conclusion:

The prevalence of RRD after LASIK was low at our institute. Anatomical and visual outcomes were acceptable in eyes that were managed promptly. Although there is no cause-effect relationship between LASIK and RRD, a dilated fundus examination is highly recommended before and after LASIK for myopia.

Simultaneous measurement of intraocular pressure in the anterior chamber and the vitreous cavity

PURPOSE

To simultaneously measure, using manometry, the changes of intraocular pressure (IOP) in the anterior chamber and in the vitreous cavity of a single porcine eye, induced by an external column of water.

METHODS

We prospectively measured IOP simultaneously in seven freshly enucleated porcine eyes in both the anterior chamber and the vitreous cavity. Measurements were obtained through blood-pressure transducers connected to 21-gauge catheters. A third cannula was inserted into the anterior chamber to increase the IOP; when the cannula was connected to the water column, the pressure increased rapidly from 0 to 180 mmHg. Changes were registered every 5 seconds during the first minute. Statistical analysis was performed using the Wilcoxon signed-rank test. P ≤ 0.05 was considered significant.

RESULTS

Before the IOP was increased, the median basal IOP value was 18 mmHg in the anterior chamber and 23 mmHg in the vitreous cavity (P > 0.05). Sixty seconds after the end of the experiment, the median IOP value was 135 mmHg (range 122-145) in the anterior chamber and 55 mmHg (range 16-68) in the vitreous cavity (P < 0.01).

CONCLUSION

Cannulation of the anterior chamber measures the actual IOP; however, the IOP measured by cannulation in the vitreous cavity using the same catheter diameter was different, possibly because of the viscosity of the vitreous. The viscosity of the vitreous probably makes the cannulation method of IOP evaluation in the vitreous cavity inaccurate.

Comparison of real-time intraocular pressure during laser in situ keratomileusis and epithelial laser in situ keratomileusis in porcine eyes

PURPOSE

To compare real-time intraocular pressure (IOP) between laser in situ keratomileusis (LASIK) and epithelial LASIK (epi-LASIK) in porcine eyes during flap creation using a microkeratome or an epikeratome, respectively.

SETTING

Vissum Madrid, Madrid, Spain.

METHODS

In this prospective study, a Moria microkeratome was used in 1 eye (LASIK group) and an Epi-K epikeratome in the other eye (epi-LASIK group) to create a lamellar corneal flap and an epithelial flap, respectively, in freshly enucleated porcine eyes. The IOP changes during the procedures were recorded by direct cannulation using a reusable blood pressure transducer connected to the anterior chamber.

RESULTS

Each group comprised 17 eyes. In the LASIK group, the mean IOP was 113.65 mm Hg +/- 10.78 (SD) during suctioning and 112.35 +/- 11.51 mm Hg during cutting phases. The mean duration of the phases was 9.00 +/- 1.46 seconds and 6.06 +/- 1.14 seconds, respectively. In the epi-LASIK group, the mean IOP was 92.57 +/- 20.86 mm Hg during suctioning, 82.09 +/- 20 mm Hg during cutting, and 67.28 +/- 13.49 during low vacuum. The mean duration of the phases was 25.88 +/- 1.96 seconds, 33.82 +/- 2.81 seconds, and 29.71 +/- 3.29 seconds, respectively. The IOP values were significantly different between the 2 groups (all comparisons P<.05).

CONCLUSION

Real-time IOP measured during suctioning and flap creation by direct cannulation of the anterior chamber in freshly enucleated porcine eyes showed a significant increase in IOP during LASIK and epi-LASIK; the increase was lower in the epi-LASIK group.

Pneumatic trabeculoplasty vs latanoprost as adjunctive therapy to timolol in primary open-angle glaucoma or ocular hypertension

PURPOSE

To evaluate the efficacy and safety of pneumatic trabeculoplasty (PNT) compared with latanoprost 0.005%, in primary open-angle glaucoma (POAG) and ocular hypertension (OH) not controlled by timolol 0.5%.

PROCEDURES

In a randomized clinical study, 18 patients affected with primary open-angle glaucoma (POAG) or ocular hypertension (OH) with intraocular pressure (IOP) >20 mmHg after timolol 0.5% in one eye were treated with PNT; 18 control eyes received adjunctive therapy with latanoprost 0.005%. Visual acuity, IOP, visual field, biomicroscopy findings and fundus appearance were evaluated at each month. Patients with IOP >20 mmHg were excluded from the study. The study was continued until in one group no patients were left.

RESULTS

At 1 month, IOP had decreased significantly in both groups. In PNT-treated eyes the mean IOP decrease was 4.5 +/- 1.8 mmHg (19.1 +/- 7.8%) and in latanoprost-treated eyes was 6.6 +/- 1.3 mmHg (28.2 +/- 5.7%) (between two groups, P < 0.001). Eleven PNT-treated eyes (61%) and 17 latanoprost-treated eyes (94%) had an IOP reduction of more than 20% of baseline value (P = 0.049); two PNT-treated patients received additional therapy. At the following months, in the latanoprost group, IOP was stable: an IOP reduction of 20% or more was seen in 89% of the eyes. In some PNT-treated eyes IOP increased: at 2 months, an IOP reduction> or =20% was seen in 50%, at 3 months in 33%, and at 4 months in 17% of the eyes. (between the two groups, respectively, P = 0.03, P = 0.002, P < 0.001). The number of eyes that required therapy increased progressively in the PNT group, and at 8 months all eyes had required therapy, whereas one latanoprost-treated eye had had additional therapy. After PNT, no patients had visual acuity reduction or intraocular inflammation; three eyes had subconjunctival hemorrhage and five eyes a hyperemia that regressed within 1 week. No posterior segment changes or visual field progression were detected in either groups.

CONCLUSIONS

In eyes with glaucomatous damage that is not advanced, PNT can reduce the IOP in 60% of the eyes at 1 month, and in 33% of the eyes at 3 months, without significant side-effects. The indications, efficacy and safety of PNT retreatments remain to be investigated. IOP reduction is less and of shorter duration than that obtained by latanoprost adjunctive therapy.

Laser refractive surgery in a patient with a prepapillary arterial loop

PURPOSE

To present a patient with a prepapillary vascular loop, a congenital anomaly that has been associated with vitreous hemorrhage and retinal vascular occlusion, who underwent refractive surgery.

METHODS

A 45-year-old man with 2.00 diopters (D) of myopia and a unilateral prepapillary arterial loop presented with an interest in LASIK. After consideration of the theoretical risks of LASIK, the patient underwent photorefractive keratectomy with manual de-epithelialization and a scanning spot excimer laser.

RESULTS

Postoperatively, uncorrected visual acuity was 20/20, visual field testing was normal, and no complications occurred. Follow-up was 4 years.

CONCLUSIONS

Surface ablation was a safe method in a low myopic patient with a prepapillary vascular loop. This case emphasizes the importance of a thorough vitreoretinal examination in laser refractive candidates.

Undetected development of glaucoma after radial keratotomy

PURPOSE

To report a case of advanced glaucomatous optic atrophy years after bilateral radial keratotomy.

METHODS

Multiple intraocular pressure (IOP) measurements of both eyes in a 40-year-old woman who underwent previous bilateral radial keratotomy were obtained using Goldmann applanation tonometry as well as air-puff and Schiotz tonometry. In addition to regular eye examinations, corneal thickness, surface, and shape were examined using Orbscan and C-Scan.

RESULTS

The cornea of both eyes did not show signs of corneal thinning, but flattening of the corneal surface was observed. The decreased corneal curvatures precipitated a misjudgment of IOP readings measured by central applanantion tonometry (12 to 18 mmHg), whereas impression and non-contact tonometry revealed elevated IOP values (21 to 27 mmHg).

CONCLUSIONS

Changes of the corneal shape without corneal thinning can lead to falsely low IOP values. Therefore, in eyes that have undergone corneal refractive surgery, non-Goldmann measurement of IOP and continued examination of the optic nerve and possibly visual fields are recommended.

Immediate retinal detachment after laser in situ keratomileusis

PURPOSE

We report a case of rhegmatogenous retinal detachment immediately (first postoperative day) after the refractive surgery of laser in situ keratomileusis (LASIK).

CASE REPORT

A 50-year-old man underwent bilateral LASIK; on the first postoperative day, he presented with decreased visual acuity due to retinal detachment with vitreous hemorrhage in the left eye. There were two horseshoe tears posterior to the equator and one peripheral operculated hole, all temporally located. Four months later, he presented with vitreous hemorrhage and a horseshoe tear temporal posterior to the equator in the right eye.

RESULTS

Surgical treatment was done, and the retina reattached immediately after surgery and remained stable thereafter in both eyes. Six months after surgery, visual acuity was 20/30 in the left eye and 20/40 in the right eye.

CONCLUSION

Although the cause/effect relationship between LASIK and retinal detachment has not yet been established, occurrence of immediate postoperative retinal detachment may represent a strong temporal suggestion of its association.

Importance of fundoscopy in refractive surgery

PURPOSE

To examine the incidence, treatment, and outcomes of retinal lesions before and after refractive laser surgery.

SETTING

Private refractive surgery practice.

METHODS

A retrospective review was conducted of patients attending the laser clinic over a 3-year period. Examined were the incidence, type, management, and outcomes of the posterior segment abnormalities encountered.

RESULTS

Fifty two (1.1%) of 4800 patients had posterior segment pathology requiring intervention. Forty-five cases (0.86%) were detected preoperatively and had a mean refraction of -4.5 diopters (D) +/- 3.0 (SD). Seven cases (0.14%) were detected postoperatively at a mean follow-up of 19 +/- 18.3 months; none had preoperative pathology. The mean refraction in this group was -4.4 +/- 2.3 D. Ninety-five percent had myopic prescriptions. All maintained best corrected visual acuity postoperatively. The incidence of retinal detachment was 0.03% per year in the myopic candidates; however, no cases occurred after the refractive procedure.

CONCLUSION

Dilated fundus examination is an integral part of optimum clinical care in refractive patients, and shared preoperative assessment by a retinal specialist is advisable in those with predisposing retinal pathology.

Ocular Structure Changes During Vacuum by the Hansatome Microkeratome Suction Ring

PURPOSE

To evaluate whether the vacuum of a microkeratome suction ring induces ocular structure changes.

METHODS

A prospective case series using A-scan ultrasonography to measure anterior chamber depth, lens thickness, vitreous body, and axial length was performed. Measurements before and during application of a Hansatome microkeratome suction ring were performed on 69 eyes of 39 consecutive patients scheduled to undergo a first-time LASIK procedure with mechanical creation of a corneal flap.

RESULTS

Mean patient age was 43 +/- 12.1 years. Of the 69 eyes, 63 (91.3%) had refractive myopia with a mean spherical equivalent refraction of -2.93 +/- 1.56 diopters (D) and 6 (8.7%) had refractive hyperopia with a mean spherical equivalent refraction of 1.37 +/- 0.31 D. Overall, the mean spherical equivalent refraction of all eyes was -2.56 +/- 1.94 D. Ultrasound measurements during suction revealed a decrease in the anterior chamber depth of -0.06 +/- 0.36 mm (P < .05) and lens thickness by -0.14 +/- 0.45 mm (P < .05) whereas the vitreous body increased 0.25 +/- 0.36 mm (P < .05). Although insignificant, a trend toward increasing axial length was noted. No measurements changed over time during the application of vacuum.

CONCLUSIONS

Vacuum by a microkeratome suction ring induced a compression of the anterior chamber and lens with commensurate expansion of the vitreous body. The assessment of vacuum effects during LASIK suggests that measurements of intraocular compartments are more informative than axial length.

[Reactivation of ocular toxoplasmosis after laser in situ keratomileusis]

Laser in situ keratomileusis (LASIK) is a safe and efficient refractive surgical procedure that provides excellent results in most cases. Several complications have been reported, most of them related to the posterior segment of the eye. Although they are quite rare, a growing number of vitreoretinal pathologic conditions after LASIK have been reported. To date no article has reported an inflammatory or infectious disease of the posterior segment after a LASIK procedure. We report a case of reactivation of toxoplasmic chorioretinitis that occurred 5 days after a LASIK procedure. Clinical outcome was spontaneously favorable after 1 month, with no loss of vision. Although a causal effect between LASIK and toxoplasmic chorioretinitis reactivation cannot be proven with a single case report, we stress the importance of dilated fundus examination in LASIK preoperative assessment: our case suggests that in the presence of preoperative toxoplasmic chorioretinitis scars, increased retinal monitoring is required.

Rhegmatogenous Retinal Detachment After LASIK for Myopia

PURPOSE

To report the characteristics and incidence of rhegmatogenous retinal detachment in myopic eyes after LASIK.

METHODS

The medical records of 49 patients with rhegmatogenous retinal detachment after LASIK were reviewed. The incidence of rhegmatogenous retinal detachment after LASIK was determined and potential risk factors were evaluated.

RESULTS

LASIK was performed on 59,424 eyes with spherical equivalent refraction (SE) ranging from -0.75 to -26.50 diopters (D) (mean: -6.10 +/- 3.5 D). Forty-nine eyes developed rhegmatogenous retinal detachment between 1.5 and 76 months (mean: 27.3 +/- 21.7 months) after LASIK. The mean preoperative refractive error in these eyes was -8.6 +/- 3.9 D. Mean age of these patients was 38.2 +/- 11.2 years. Thirty-five (71.4%) patients were male. The cumulative incidence of rhegmatogenous retinal detachment was 0.082% (95% confidence interval [CI]: 0.061-0.109), and the yearly incidence was 0.032% (95% CI: 0.023-0.042) after LASIK. The most frequent location of the retinal breaks was the superior temporal quadrant (22.7%). Male sex, older age, and higher preoperative myopia were significantly related to the incidence of rhegmatogenous retinal detachment after LASIK (P<.001).

CONCLUSIONS

Based on the results of this study, following the treatment of high-risk peripheral retinal lesions, LASIK did not appear to be an additional risk factor for the development of rhegmatogenous retinal detachment after LASIK in our patients; however, patients should be informed of the possibility of this complication as a consequence of myopia. Patients who are male, older in age, and have high myopia preoperatively may be at increased risk.

Excimer laser surgery for correction of ametropia after cataract surgery

PURPOSE

To review the cases of patients who had excimer laser refractive surgery to correct unintentional or undesired ametropia after cataract extraction with intraocular lens (IOL) implantation.

SETTING

Wilmer Laser Vision Correction Center, Wilmer Eye Institute, Baltimore, Maryland, USA.

METHODS

In this retrospective noncomparative review of consecutive cases, the Wilmer Laser Vision Correction Center's database was searched for patients who had laser in situ keratomileusis or photorefractive keratectomy to correct ametropia after cataract extraction with IOL implantation.

RESULTS

Using the Visx Star excimer laser system (Visx, Inc.), 11 procedures were performed in 11 eyes of 10 patients a mean of 47 months (range 2 to 216 months) after cataract extraction with IOL implantation. Except for 1 patient with a silicone plate lens, all patients received 3-piece poly(methyl methacrylate) lenses. The mean age at time of excimer treatment was 75 years (range 70 to 81 years). Before laser surgery, the mean spherical equivalent of patient eyes was -3.76 diopters (D) +/- 2.50 (SD) (range -6.50 to +0.75 D), spherical refraction ranged from -9.00 D to plano, and the highest cylindrical refraction was +5.50 D. At last follow-up (mean 12.2 months; range 1 to 38 months), the mean manifest spherical equivalent was -0.88 +/- 1.43 D (range -2.75 to +2.13 D). Changes in mean manifest spherical equivalent were highly significant (P = .03, Wilcoxon signed rank test for paired values). There was no difference between targeted and achieved postoperative refraction (P = .34, Wilcoxon test). Increasing age was correlated with a hyperopic shift (r = 0.525, P = .05). All patients were satisfied with their final uncorrected visual acuity (UCVA), which improved in every case. Except for 1 patient in whom an epiretinal membrane developed, best spectacle-corrected visual acuity remained unchanged or improved.

CONCLUSIONS

In this series of patients, who were a few decades older than the typical excimer laser candidate, laser refractive surgery was a safe, effective, and predictable method to correct ametropia after cataract extraction with IOL implantation. It may be a viable, noninvasive alternative to intraocular surgery, which has potential complications. Although satisfactory for all patients, final UCVA was not as high as that reported in laser refractive surgery patients in general, and this result may be because of prior cataract extraction with IOL implantation or increased age.