Light-induced maculopathy

Light as a drug: prospective randomized evaluation and comparison of the effect of decreased illumination on visual recovery after cataract surgery

PURPOSE

To compare the effect of decreased illumination on the rate of postoperative visual recovery, and the incidence of cystoid macular edema (CME) with surgical visualization achieved with a traditional analog operating microscope compared with a 3D digital visualization system.

SETTING

Ambulatory surgery center, New York.

DESIGN

Prospective, randomized, consecutive, single-surgeon series.

METHODS

Patients undergoing routine cataract surgery were randomized into either (1) visualization through the binoculars of a standard operating microscope ("traditional group") or (2) visualization through a 3D digital visualization system affixed to the same operating microscope ("digital group"). Note was made in each case of light intensity used, light exposure time, cumulative dissipated energy (CDE), femtosecond laser use, preoperative medical and ocular conditions, intraoperative and/or postoperative complications, and preoperative and postoperative visual acuities and optical coherence tomography confirmed CME.

RESULTS

The study comprised 118 eyes in the traditional group and 96 eyes in the digital group. There were no differences in preoperative visual acuity, light exposure time, CDE, or femtosecond laser use between groups, but the light intensity used in the digital group was significantly less (19.5% ± 0.5%) than in the traditional group (48.6% ± 0.6%; P < .001). Furthermore, the digital group achieved a better decimal postoperative day 1 visual acuity (0.60 ± 0.03) with less rates of CME (2.1%) when compared with that of the traditional group (0.51 ± 0.02, P = .03; and 9.2%, P = .03), respectively.

CONCLUSIONS

Visual recovery and CME rates were significantly better in patients who underwent cataract surgery assisted by the 3D digital visualization platform without an increase in complications or surgical time.

Efficacy of 3D digital visualization in minimizing coaxial illumination and phototoxic potential in cataract surgery: pilot study

PURPOSE

To compare the coaxial light intensity required during cataract surgery and rate of postoperative visual recovery, with surgical visualization achieved with a traditional analog operating microscope compared with a 3D digital visualization system.

SETTING

Weill Cornell Medical Center, New York Presbyterian Hospital, New York, New York.

DESIGN

Retrospective, consecutive, single-surgeon series.

METHODS

Patients undergoing femtosecond laser-assisted cataract surgery were retrospectively grouped into either: (1) visualization using the binoculars of a standard operating microscope (traditional group) or (2) visualization using a 3D digital visualization system affixed to the same operating microscope (digital group). Note was made in each case of light intensity used, light exposure time, intraoperative and/or postoperative complications, and postoperative visual acuities.

RESULTS

The study comprised 24 eyes in the traditional group and 27 eyes in the digital group. There were no intraoperative or postoperative complications in either group and no difference in mean light exposure time, but the mean light intensity used in the digital group was significantly less (18.5% ± 1.5%) than that in the traditional group (43.3% ± 3.7%; P < .001). Furthermore, the digital group achieved a postoperative day 1 visual acuity that was within 2 lines of the postoperative month 1 visual acuity a greater percentage of time than that in the traditional group (81.5% of eyes vs 54.2% of eyes; P = .04).

CONCLUSIONS

Light intensity was significantly decreased in patients who underwent cataract surgery assisted by the 3D digital visualization platform without an increase in complications or surgical time and possibly with a faster postoperative visual recovery.

Lux study: Contribution of a three-dimensional, high dynamic range, ultra-high-definition heads-up visualization system to a significant delivered light intensity decrease during different types of ocular surgeries

OBJECTIVE

To explore the hypothesis that using a large, three-dimensional (3D), ultra-high-definition (4K), heads-up display (HUD) system in a real-life setting may be associated with a significant reduction in light intensity (LI) delivered during various types of eye surgery.

METHODS

Single center, post-learning curve observational study of 142 independent consecutive cases: 73 cataracts and 69 vitrectomies (VR). For each group, the only variable setting was the LI. The LI delivered by each source was calibrated in lumens (lm).

RESULTS

In the VR group, the delivered LI dramatically decreased from the 80% reference to 27.8%±13.2% (P<0.0001) (4.3 to 1.5lm). Among these surgeries, 91.3% needed 40% or less LI (2.3lm). The corneal transparency and quality of pupil dilation showed some correlation with the results. In the cataract group, the difference was even more spectacular, from 80% to 15%±11.3% (P<0.0001) (2.5 to 0.3lm). Among these surgeries, 80.8% required less than 20% LI (0.5lm). The surgical time, LI variations and type of cataract seemed to influence the results, down to 9.6%±5.4% (P<0.0001) (0.22lm) for nuclear cataracts, which represented 63% of the cataract sample.

CONCLUSION

The digital signal amplification with this HUD system allows comfortable posterior as well as anterior segment surgery despite the decrease in incident light, suggesting an unprecedented reduction in the risk of phototoxicity compared to conventional systems as well as a likely improvement in patient comfort.

Iatrogenic retinal traumas in ophthalmic surgery

BACKGROUND

To describe the main retinal iatrogenic traumas possibly related to ophthalmic surgery and the precautions to be adopted to avoid them.

METHODS

The article reviews the main peer-reviewed literature concerning retinal injuries caused by surgically related maneuvers. Safety measures alleged to inhibit any possible iatrogenic damage are also evaluated.

RESULTS

Photochemical damage of the retina, retinal complications after strabismus surgery, retinal complications related to local anesthesia for ophthalmic surgery, retinal damage during cataract surgery and retinal damage during vitreoretinal surgery are the most common iatrogenic retinal injuries. Their incidence is related to risk factors peculiar to each condition.

CONCLUSIONS

Ophthalmic surgeons are aware that there are a number of circumstances in which several undesirable retinal iatrogenic injuries might occur, sometimes with serious consequences. This is why surgeons should take every precaution at each surgical step to avoid any possible retinal iatrogenic damage.

Phototoxic effects of commercial photographic flash lamp on rat eyes

BACKGROUND

To determine whether exposure of the cornea and retina of rats to flashes from a commercial photographic flash lamp is phototoxic.

METHODS

Sprague-Dawley rats were exposed to 10, 100, or 1,000 flashes of the OPTICAM 16M photographic flash lamp (Fujikoeki, Japan) placed 0.1, 1, or 3 m from the eyes. Corneal damage was assessed by a fluorescein staining score, and the retinal damage by eletroretinography (ERG) and histology before and 24 h after exposure.

RESULTS

Exposure of the eyes to 1,000 flashes at 0.1 m increased the fluorescein staining score significantly (P = 0.009, the Mann-Whitney test). Scanning electron microscopy (SEM) of the cornea showed a detachment of the epithelial cells from the surface after this exposure. The amplitude of the a-wave was decreased significantly by 23.0% (P = 0.026) of the amplitude before the exposure, and the b-wave by 19.7% (P = 0.0478) following 1,000 flashes at 0.1 m but not by the other exposures. TUNEL-positive cells were present in the outer nuclear layer only after the extreme exposure, but no significant decrease in retinal thickness was seen under any condition. The fluorescein staining score and ERGs recovered to control levels within 1 week.

CONCLUSIONS

Light exposure to a photographic flash lamp does not induce damage to the cornea and retina except when they are exposed to 1,000 flashes at 0.1 m.

Phototoxic maculopathy after secondary intraocular lens implantation

We report phototoxic maculopathy in 2 aphakic patients after secondary, scleral-sutured intraocular lens implantation. This rare complication may have been triggered by drugs that increased the photosensitivity of the tissue. Careful preoperative assessment is necessary to question the receipts of photosensitizing drugs and identify diseases that predispose patients to phototoxic injuries.

Study of the effect of involuntary user movement on the potential light hazards from some ophthalmic instruments

A study was undertaken to determine whether involuntary user movement provides a basis for relaxing the measurement conditions for evaluating the potential optical radiation hazards to the eye from slit lamps and indirect ophthalmoscopes. This was accomplished by assessment of the extent to which light from these devices can be maintained in focus on a 1-mm-diameter fiber-optic cable for 45 s. The results suggest that, although involuntary user movements can be significant, they do not provide a basis for relaxing the measurement conditions for evaluating the potential optical radiation hazards to the cornea and lens from slit lamps and indirect ophthalmoscopes.

Study of filtered light on potential retinal photic hazards with operation microscopes used for ocular surgery

There have been numerous reports of retinal photic injury from operation microscopes used during cataract surgery. The risk of injury has been associated with the intensity of the light directed into the eye, short-wavelength emission, user technique, exposure time, and direct axial lighting. We evaluated use of light transmission filters to modify a tungsten-halogen light source spectrum to reduce the risk of retinal photic injury. A two-light source filter combination was found with a color profile acceptable for intraocular surgery that reduces the risk of retinal photic injury by a factor of approximately 2.5.

Protecting the retina during MemoryLens insertion

BACKGROUND

To determine the light-scattering power of the folded MemoryLens(R).

SETTING

Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA.

METHODS

The focusing power of 10 unfolded MemoryLenses (Mentor Ophthalmics) was measured using an optical bench. The IOLs were then unfolded in a 37 degrees C distilled water bath and reexamined within 15 seconds of removal from the bath. Resolutions were read after the lenses were dried for 1 hour and cooled to room temperature and again after they were rehydrated and reheated in the water bath.

RESULTS

In the rolled state, all lenses diffused the illumination of the light source. After the IOLs were unfolded in the water bath at 37 degrees C, they gave readings of acceptable to high resolution. After the lenses were air dried for 1 hour and cooled to room temperature, the resolution of all lenses decreased. However, after the IOLs were rehydrated and reheated for 1 more hour, resolution was similar to that of the original hydrated lenses.

CONCLUSION

When folded, at a low temperature, or dehydrated, the MemoryLens may provide protection from the operating microscope by scattering light.

Principles of microsurgery

The surgical principles and techniques used in ophthalmic microsurgery differ considerably from those used in general surgery. Successful ophthalmic microsurgery requires that the surgeon understand not only the design and complexities of the operating microscope, but how tissues are affected by minute manipulations with microsurgical instruments. Furthermore, ophthalmic microsurgery requires a detailed understanding of how microsurgical techniques need to be adjusted to accommodate the unique features of ocular tissues such as conjunctiva, cornea, and lens. A diligent effort to master the principles of ophthalmic microsurgery is probably the single most important prerequisite to becoming an accomplished ophthalmic surgeon.

Updating on intraoperative light-induced retinal injury

We are presenting the state of knowledge concerning intraoperative light-induced retinal injury, considered to be a combination of photic retinopathy and retinal photocoagulation. It may arise from retinal light exposure to the operating microscope or to the fiberoptic endoilluminator. Ultraviolet and short-wavelength visible light are more dangerous than longer wavelength light. Many risk factors may facilitate the onset of this iatrogenic disease following surgery. Many aspects of the retinal damage are still poorly understood. Many mid light-induced retinal injuries probably remain undiagnosed in routine postoperative examination. Current appropriate light filters are not the definitive solution. Appropriate precautions should be taken during both anterior segment and vitreoretinal surgery.

Subclinical operating microscope retinopathy: the use of static perimetry in its detection

Focal retinal pathology and dysfunction as a sequel to manifest damage due to operating microscope illumination is well recognised. We wished to determine whether retinal dysfunction could be identified in the absence of clinically visible lesions. We therefore have conducted a prospective controlled study on 36 patients undergoing cataract surgery and 27 control subjects. A Wild M690 zoom operating microscope was used for each procedure. No filters were used. The Humphrey visual field equipment was employed to determine threshold retinal sensitivity at predetermined loci above and below fixation in both groups. No clinically visible retinal lesions were seen in any patient. However, post-operative investigation revealed a statistically significant depression in retinal sensitivity at points most exposed to operating microscope illumination (p < 0.05). This was most noticeable following longer total operating times and in patients with the longest time intervals between lens extraction and completion of the procedure. It is concluded that operating microscope position and centration, and the position of the eye, should be adjusted to place the image of the illuminating element away from the foveola. Also retinal illumination should be kept to a minimum, particularly after an intraocular lens has been implanted.

Retinal pigment epitheliopathy after macular hole surgery

BACKGROUND

Full-thickness idiopathic macular holes were previously considered untreatable, but surgical intervention has been proposed to collapse the hole and improve vision. This study evaluates the fluorescein angiographic changes that occur after macular hole surgery.

METHODS

Sixteen patients with stage III idiopathic macular holes underwent pars plana vitrectomy, removal of the posterior hyaloid, peeling of fine epiretinal sheets along the edges of the holes, and fluid-gas exchange. Preoperative fluorescein angiograms were performed, and best-corrected preoperative visual acuity was 20/200 or less in all eyes.

RESULTS

Postoperatively, the macular hole disappeared in 12 eyes (75%). In all 12 eyes, retinal pigment epithelial swelling was present, with a unique fluorescein angiographic appearance. This pattern slowly resolved over months, with gradual visual improvement but residual retinal pigment epithelial mottling. Systemic and periocular steroids had no significant impact on the process.

CONCLUSION

The combination of prolonged intraocular gas contact and light exposure exceeding threshold for an already compromised macula appears to be responsible for this pigmentary pattern. Depending on the severity of the pigment epithelial alteration, this unique pattern may portend a guarded visual prognosis in affected patients undergoing successful macular hole repair.

Photic maculopathy after extracapsular cataract surgery. A prospective study

Photic retinal injuries have been described after surgical exposure to the intense illumination systems of operating microscopes. The overall incidence of such injuries has been postulated at less than 10%. The authors prospectively studied 43 consecutive patients to determine the incidence of photic macular injuries during cataract surgery. Patients underwent complete ophthalmic examinations, fundus photography, and oral fluorography before and after surgery. Photic macular injuries developed in 12 of 43 eyes (28%) as a result of intraocular surgery. This incidence is much higher than previous estimates. The association with possible risk factors, cystoid macular edema, and the effect of these injuries on final visual acuity are discussed.

Pathologic findings of photic retinopathy in the human eye

The macular retina of a patient whose eye was scheduled for enucleation because of progressive growth of a malignant melanoma that had invaded the iris and filtration angle was exposed to unfiltered light from the operating-room microscope for 60 minutes. Photic maculopathy was documented with fundus photography and fluorescein angiography 67 hours after light exposure. Seventy-two hours after light exposure, the eye was enucleated, fixed in Trumpe's solution, and studied with light microscopy and electron microscopy. Findings included localized necrosis of the retinal pigment epithelium; loss of the apical villi, plasma membranes, and cytoplasmic organelles; extrusion of pigment granules; and extensive disruption of the outer lamellae of the photoreceptors. The inner segments of the photoreceptors were edematous and contained swollen mitochondria. Near the margins of the photic retinopathy, thinned retinal pigment epithelial cells appeared to have migrated under injured retinal pigment epithelial cells, suggesting early attempts at repair. Additional findings included Müller-cell swelling.

Operating microscope-induced retinal phototoxicity: pathophysiology, clinical manifestations and prevention

Retinal light damage is a poorly understood phenomenon, due to its multifactorial etiology and relatively infrequent recognition. It has been increasingly identified following ocular surgery involving the intense light of the operating microscope. The authors describe the clinical entity, review salient features of its pathophysiology and provide guidelines for prevention of retinal phototoxicity.

Evaluation of phototoxic retinal damage after argon laser iridotomy

We performed several visual function tests in 17 eyes (ten patients) before and after argon laser iridotomy in an effort to detect diffuse photochemical damage to photoreceptors caused by exposure to the intense, blue-green light that is transmitted into the posterior segment as the iridotomy is created and enlarged. No change was detected in static threshold sensitivity in the central 30 degrees of the field (Octopus perimeter), color sensitivity (Farnsworth-Munsell 100-Hue test), or visual acuity. Contrast sensitivity showed a small increase at low spatial frequencies and a small decrease at high spatial frequencies. The latter change was small and not necessarily laser related, but precautions to limit laser exposure of the posterior pole are prudent.

The site of operating microscope light-induced injury on the human retina

We determined the site of the focal illumination from the Zeiss OPMI-6 operating microscope on the retina of the phakic and aphakic human cadaver eye by directly observing the illuminating element image on the posterior scleral surface of the globe. With the eye straight ahead and the operating microscope level, the focal oval area of retinal illumination was located superior to the foveola in both the phakic and aphakic eye. Tilting the operating microscope 10 degrees toward the surgeon displaced the entire illuminating element image 0.50 mm below the foveola in the phakic eye and 0.25 mm below the foveola in the aphakic eye. Rotating the eye inferiorly 10 degrees displaced the entire illuminating element image 1.0 mm below the foveola in the phakic eye and 1.25 mm below the foveola in the aphakic eye. Centering the field of view superiorly (viewing the superior limbus) paradoxically displaced the illuminating element image inferiorly, resulting in central foveal illumination. Foveal light exposure was avoided in most eye positions by tilting the microscope at least 10 degrees toward the surgeon.

Microscope light-induced maculopathy in combined penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation

A characteristic retinal phototoxicity reaction was noted in four patients who underwent penetrating keratoplasty, extracapsular cataract extraction (ECCE), and intraocular lens (IOL) implantation. This complication has been well documented in association with other ocular procedures, but only one previous similar case has been reported. The authors bring this potential complication to the attention of corneal surgeons, discuss the risk factors, and offer suggestions on prevention.

Three cases with light-induced retinopathy

Three patients presented a characteristic retinopathy presumably induced by light arising from operating microscope during extracapsular cataract extraction combined with intraocular lens insertion. The operating microscope was equipped with video-recorder. Light sources were tungsten bulb. All cases were asymptomatic and an inspection at the post-operative control examination led to the detection of this type of retinopathy.

Light-induced maculopathy and cystoid macular edema

We present two patients with paramacular burns induced by the operative light microscope. In one case there was associated cystoid macular edema. Of the 34 total reported cases of paramacular burns, there have been only two cases of cystoid macular edema. Thus, although the total number of reported cases of light-induced maculopathy is small, this disorder does not appear to predispose to cystoid macular edema. Loss of visual acuity is mainly caused by the proximity of the burn to the fovea.

A model for predicting the site of paraxial retinal lesions secondary to "coaxial" operating microscope illumination systems

We measured a 15 +/- 2-mm displacement of the illuminating element of the coaxial operating microscope from the true optical center of the microscope. We further calculated the displacement of the image of the illuminating element of the operating microscope on the retina of the simplified schematic eye and found that the "coaxial" operating microscope would focus the light between 1.3 and 1.8 mm superior to the fovea of the eye, depending on the theoretical refractive status of the simplified eye. Actual measurements on a simulated retina (35-mm camera) confirmed the calculated displacements. The deviation varied with eye tilt and microscope position. We also found that the maneuvers commonly used by anterior segment surgeons of tilting the microscope and rotating the eye downward tended to displace the image of the illuminating element closer to the fovea, increasing the chance for symptomatic retinal damage. A combination of such maneuvers may reduce the potential for clinically significant retinal phototoxicity by displacing the light further inferior to the fovea.

Effects of yellow filter glasses on colour discrimination of normal observers and on the illumination level

Ten healthy young persons wearing yellow filter glasses were examined with the Farnsworth-Munsell 100-hue test using a Macbeth daylight illuminator. Results obtained with (Schott) filters GG 400, GG 420, GG 435 and GG 455 were within normal limits. Using filters GG 475, GG 495 and OG 515 the mean total error score was 123.9, 203.8 and 226.9, respectively, and the test diagram showed a tritan error axis. Illumination of the Macbeth daylight illuminator measured without filters was 1800 lux. Using yellow filters the illumination varied from 1650 to 1500 lux.

Effect of age on visual acuity after cataract extraction

The best Snellen visual acuity in the three months after cataract extraction was found to decline with the age of the patient. The relationship was identical in 111 patients who had extracapsular extraction and a Pearce tripod posterior chamber intraocular lens and in 50 patients who had intracapsular extraction with spectacle correction. Vision after operation varied from a mean value of 6/5 at 50 years to 6/12 at 90 years, a decline of 1 line per 13.4 years. In the intracapsular group, over a mean follow-up period of 14 years, the rate of fall in acuity with increasing age after operation was found to be statistically similar to that of the early postoperative acuity plotted against age for both types of operation. This suggests that the rate of decline with age is unchanged after a prolonged period of aphakia with presumed increased exposure to ultraviolet and blue light. The data were found to be similar to the decline in the neurosensory elements of vision with age measured experimentally in 20 phakic subjects by laser interferometry. This method of assessment of contrast sensitivity threshold effectively bypasses changes in the optical media. The findings indicate that the previously recognised drop in visual acuity with age is not related to changes in the aging crystalline lens and support the view that there is a decline in the neurosensory elements of vision. It is important to recognise this deterioration so that results of surgery or other treatment are adjusted to allow for the age of the patients.

The spectra, classification, and rationale of ultraviolet-protective intraocular lenses

I measured the spectral transmittance of 16 implantable intraocular lenses from 12 manufacturers and examined the rationale for using ultraviolet-absorptive intraocular lenses to protect pseudophakic individuals from photic retinopathy. Each ultraviolet-protective lens was classified by the wavelength at which its spectral transmittance fell to 10% in the blue or ultraviolet region of the spectrum. Current ultraviolet-protective intraocular lenses differ in the effectiveness of their protection against photic retinopathy, and product descriptions may be misleading.

Photic retinopathy from the operating room microscope

Photic retinopathy was produced in two patients after a 60-minute exposure to light from an operating room microscope (Zeiss OpMi 6). The first patient had a blind eye with clear (phakic) media and a normal-appearing retina. A 60-minute exposure produced an oval gray lesion in the posterior pole at the level of the pigment epithelium. With an ultraviolet-400 filter added for a second exposure, a second lesion was produced. The second patient received a 60-minute exposure (without an ultraviolet filter) 72 hours before enucleation for a malignant melanoma. This produced photic retinopathy that resulted in a slight decrease in central visual acuity and a dense paracentral scotoma. This conclusively establishes a cause-and-effect relationship between exposure to the light from an operating room microscope and a retinal lesion in the human eye.