Photic maculopathy after extracapsular cataract surgery. A prospective study

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.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

PURPOSE

To evaluate the potential toxicity of operation microscopes with halogen and light emitting diode (LED) light source on the rabbit eyes.

MATERIALS AND METHODS

Thirty-two eyes of 16 male New Zealand pigmented rabbits were involved in the study. The rabbits were divided into two groups according to the type of light source applied. Only one eye of each rabbit was exposed to illumination light, unexposed fellow eyes served as the control group. Experimental groups included group 1 exposed to halogen light for 2 h and evaluated 1 day and 1 week after the illumination, group 2 exposed to LED light for two hours and evaluated 1 day and 1 week after the illumination. On the first and seventh days after exposing the light, we evaluated the rabbit corneas using in vivo confocal microscopy (IVCM). At the end of the seventh day, the Hematoxylin-eosin staining and TUNEL staining were performed to investigate the presence of apoptosis in the retina and retina pigment epithelium.

RESULTS

Early IVCM findings revealed corneal epithelial cell ovalization and indistinct intercellular borders in the halogen light group. We also observed more increase in the keratocyte density index (23.7% vs 14.1%, p = 0.001, respectively) and the Bowman reflectivity index (12.4% vs 4.1%, p = 0.001, respectively) at first day of the light exposure in halogen light group compared to LED light group. However, late IVCM indicated that these findings disappeared one week later. No apoptosis was observed in the corneal and retinal layers in early and late examination groups.

CONCLUSION

The present experimental study demonstrated that both halogen and LED lights, which were commonly used for microscopic eye surgery, had no sustained adverse effect on the cornea and retina of the rabbits; however, halogen light had a temporary adverse effect on corneal epithelium and stroma, which resolved within 1 week.

Phototoxic maculopathy due to extreme usage of infrared illuminator-assembled night-vision handheld scope

Night-vision handheld scopes are of wide use in military operations at dark conditions. In some cases in the battlefield, as in our case report, if there is no light coming from any source (neither from Moon nor from Stars), infrared light-emitting diode illumination can be coupled with night-vision goggles. Reflected illumination from the target is mostly blue filtered through the night-vision goggles objective lens. Retinal damage induced by unfiltered blue light and visible light has been previously reported. We described a phototoxic maculopathy induced by night-vision handheld scope assembled with infrared light-emitting diode illuminator in two soldiers who are on duty at nights for nearly two-thirds of the last year. The phototoxic maculopathy can represent with typical optical coherence tomography findings such as intraretinal hyperreflective accumulation particularly located on the surface of outer retinal segments defect or presumably in the vicinity of the light passageway. Here, we presented a unique factor causing phototoxic maculopathy.

Photic maculopathy: A review of the literature (ii)

The human retina, as transducer of light energy, is especially exposed to light toxicity. Solar maculopathy has been the only form of photic maculopathy for millennia, often secondary to the observation of an eclipse. During the last century, technological advances have led to the appearance of new forms of photic maculopathy, related to the exposure to new forms of artificial light, such as welding devices and lasers. In recent years the general use of laser pointers has led to an upturn in interest in this pathology. The aim of this review is to offer an integrated view of the different types of photic maculopathy. Due to the extension of the topic, the review is presented divided into 2 parts. In this second part, atomic bomb maculopathy, laser maculopathy, iatrogenic forms of photic maculopathy, and foveomacular retinitis are presented.

Bilateral Photic Maculopathy Following Pterygium Excision: Spectral Domain Optical Coherence Tomography Findings

PURPOSE

To report high resolution spectral domain optical coherence tomography (SD-OCT) findings in a case with bilateral photic maculopathy and resultant central scotoma following pterygium excision.

CASE REPORT

A 38-year-old man with a history of pterygium excision complained of visual disturbance and annoying central scotoma in both eyes. Although he had subtle funduscopic and angiographic changes, SD-OCT precisely showed disruption of the photoreceptors inner segment/outer segment in the foveal center.

CONCLUSION

Phototoxic macular damage following ocular surgeries may be diagnosed with difficulty due to subtle funduscopic findings. SD-OCT is a precise imaging in revealing characteristic retinal alterations in different foveal injuries. Ophthalmologists should be aware of the possibility of photic maculopathy following various ophthalmic operations including pterygium surgery.

Wide-field Digital Ophthalmic Imaging in Infants using Nasal Endoscopic System

OBJECTIVE

To report the utility of nasal endoscopic system in viewing the iridocorneal angle and fundus using various nasal endoscopes and light sources and to determine which type suits best to image a given location in the eye.

METHODS

This is a prospective observational study of 20 eyes of 10 consecutive infants, who were scheduled for irrigation and probing for congenital nasolacrimal duct obstruction under general anesthesia. The pupils were dilated, viscoelastic gel was applied on the cornea and imaging was performed using nasal endoscopes. The endoscopes used were of 2.7 mm and 4 mm diameter, each with various angulations of 0(0), 30(0) and 70(0). Two different cold light illuminators (Xenon and Halogen) were used uniformly in all cases. Images were analyzed for their quality, clarity and extent of the fields captured.

RESULTS

In all the 20 eyes, nasal endoscope provided a clear circular view of the iridocorneal angle and wide-field fundus view in a single glimpse. The 4 mm endoscope offered a wider view while in-air disc analysis was better with the 2.7 mm endoscope. Angulated endoscopes were more useful in imaging the iridocorneal angle, peripheral retina up to the ora serrata and ciliary body. The image quality with the xenon and halogen light sources were found to be comparable. The time taken for a single eye examination did not exceed 5 min.

CONCLUSIONS

With good techniques and appropriate selection of nasal endoscopes, viewing of the iridocorneal angle and fundus is easy, possibly less expensive and very useful in infants.

Rapamycin attenuates visible light-induced injury in retinal photoreceptor cells via inhibiting endoplasmic reticulum stress

An extended exposure of the retina to visible light may lead to photochemical damage in retinal photoreceptor cells. The exact mechanism of retinal light damage remains unknown, and an effective therapy is still unavailable. Here, we demonstrated that rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), markedly protected 661W photoreceptor cells from visible light exposure-induced damage at the nanomolar level. We also observed by transmission electron microscopy that light exposure led to severe endoplasmic reticulum (ER) stress in 661W cells as well as abnormal endomembranes and ER membranes. In addition, obvious upregulated ER stress markers were monitored by western blot at the protein level and by quantitative reverse transcription-polymerase chain reaction (RT-PCR) at the mRNA level. Interestingly, rapamycin pretreatment significantly suppressed light-induced ER stress and all three major branches of the unfolded protein response (UPR), including the RNA-dependent protein kinase-like ER kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 (ATF6) pathways both at the protein and mRNA levels. Additionally, the inhibition of ER stress by rapamycin was further confirmed with a dithiothreitol (DTT; a classical ER stress inducer)-damaged 661W cell model. Meanwhile, our results also revealed that rapamycin was able to remarkably inhibit the activation of mTOR and its downstream factors eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), p-4EBP1, p70, p-p70, and phosphorylated ribosomal protein S6 kinase (p-S6K) in the light-injured 661W cells. Thus, these data indicate that visible light induces ER stress in 661W cells; whereas the mTOR inhibitor, rapamycin, effectively protects 661W cells from light injury through suppressing the ER stress pathway.

Adaptive multispectral illumination for retinal microsurgery

It has been shown that excessive white light exposure during retinal microsurgery can induce retinal damage. To address this problem, one can illuminate the retina with a device that alternates between white, and less damaging limited-spectrum light. The surgeon is then presented with a fully colored video by recoloring the limited-spectrum light frames, using information from the white-light frames. To obtain accurately colored images, while reducing phototoxicity, we have developed a novel algorithm that monitors the quality of the recolored images and determines when white light may be substituted by limited-spectrum light. We show qualitatively and quantitatively that our system can provide reliable images using a significantly smaller light dose as compared to other state-of-the-art coloring schemes.

Retinal light toxicity

The ability of light to enact damage on the neurosensory retina and underlying structures has been well understood for hundreds of years. While the eye has adapted several mechanisms to protect itself from such damage, certain exposures to light can still result in temporal or permanent damage. Both clinical observations and laboratory studies have enabled us to understand the various ways by which the eye can protect itself from such damage. Light or electromagnetic radiation can result in damage through photothermal, photomechanical, and photochemical mechanisms. The following review seeks to describe these various processes of injury and many of the variables, which can mitigate these modes of injury.

Prevention of suture exposure in transscleral intraocular lens fixation: an original technique

BACKGROUND

In this retrospective study, we evaluated our surgical outcomes of transscleral intraocular lens (IOL) fixation and introduced a simple, quick, and effective method to fixate and bury the sutures in the sclera to avoid suture exposure.

METHODS

Eyes were divided into 3 groups according to surgical technique. Half-thickness scleral flaps were prepared, and polypropylene suture ends were cut short in group 1 (12 eyes). Suture ends were left long without flaps in group 2 (47 eyes) and were buried into the scleral tunnel in group 3 (21 eyes).

RESULTS

The suture exposure rate was significantly lower in group 3 (0%) compared with group 2 (p = 0.006) and group 1 (p = 0.040). There was no significant difference in group 1 (25%) compared with group 2 (27.6%) (p = 1.000).

INTERPRETATION

Burying the suture ends into the scleral tunnel is a simple, safe, and effective technique for avoiding suture exposure in scleral-fixated IOL implantation.

Recovery from macular phototoxicity after corneal triple procedure

PURPOSE

Visual recovery from macular phototoxicity in 2 cases after prolonged exposure to operating microscope light from uncomplicated corneal triple-procedure surgery. Recovery is discussed in the context of repair and regeneration.

METHODS

Retrospective case reports.

RESULTS

Immediately postoperatively, both patients reported positive scotomata and were found to have macular retinal pigment epithelial depigmentation. In 1 case, the fovea was involved. By 6 to 12 months, the scotomata had disappeared despite large areas of retinal pigment epithelial hyperpigmentation remaining.

CONCLUSION

Recovery from macular phototoxicity occurs, although the mechanism remains unclear. Positive scotomata in these cases resolved over several months. The time scale of recovery was consistent with the time required for cellular replacement and possible differentiation from neural progenitor cells.

Comparison of Outcomes of Primary Scleral-Fixated versus Primary Anterior Chamber Intraocular Lens Implantation in Complicated Cataract Surgeries

OBJECTIVE

To compare the visual outcomes and complication profiles of primary scleral-fixated intraocular lens (SFIOL) versus primary anterior chamber intraocular lens (ACIOL) implantation in cataract surgeries complicated by inadequate capsular support.

DESIGN

Retrospective, interventional, comparative cases series.

PARTICIPANTS

Thirty-six eyes of 36 patients undergoing SFIOL implantation (group 1) and 46 eyes of 46 patients undergoing ACIOL implantation (group 2).

METHODS

Retrospective analysis of medical records of a consecutive series of complicated cataract surgeries with primary SFIOL or ACIOL implantation.

MAIN OUTCOME MEASURES

Postoperative best-corrected visual acuity (BCVA), intraoperative and postoperative complications, if any, and postoperative corneal endothelial cell counts. A multiple linear regression model was constructed with postoperative BCVA as the dependent variable and with IOL group (SFIOL vs. ACIOL), preoperative BCVA, surgeon's operative experience, planned operation, and patient's age as independent variables.

RESULTS

Fifty-eight percent (group 1) and 37% (group 2) of patients underwent phacoemulsification, whereas the rest underwent extracapsular cataract extraction. The mean postoperative follow-up was 33.4+/-17.9 months (range, 6-61 months). Postoperative Snellen BCVA of 20/40 or better was achieved in 47.2% (group 1) and 71.7% (group 2) of patients (P = 0.038). Regression analysis showed that primary ACIOL implantation was associated with a significantly better postoperative BCVA of -0.157 on the logarithm of minimum angle of resolution scale (95% confidence interval, -0.306 to -0.007; P = 0.040), compared with primary SFIOL implantation. Although both the number of eyes with complications and the total number of complications were higher in the SFIOL group, the differences in early (P = 0.073) and late (P = 0.377) complications were not statistically significant.

CONCLUSIONS

The results indicate that satisfactory results are achieved with primary implantation of current open-loop ACIOLs during cataract surgery complicated by loss of posterior capsule integrity. Eyes with these IOLs fared better than a cohort of eyes undergoing SFIOL implantation in a similar situation, at intermediate-term follow-up. Further prospective clinical trials with longer follow-up may help to evaluate the long-term visual outcomes and complication profiles after primary implantation of these lenses.

PHOTIC RETINOPATHY AFTER CATARACT SURGERY IN DIABETIC PATIENTS

PURPOSE

To report and emphasize photic retinopathy (PR) after cataract surgery in diabetic patients.

METHODS

The charts of 2,573 patients who underwent cataract surgery at Baskent University Hospital (Ankara, Turkey) between January 2001 and December 2003 were retrospectively analyzed for PR and diabetes mellitus (DM). All surgeries were performed using the same coaxial illuminated microscope. The diagnosis of PR was confirmed by fluorescein angiography, showing typical mottled fluorescein transmission in a well circumscribed area in each case. Statistical analyses were performed with chi2 and Mann-Whitney U tests.

RESULTS

Diagnoses of PR and DM were established in 16 cases (0.62%) and 382 cases (14.85%), respectively. DM was present in 7 (43.75%) of the PR cases. PR occurred more frequently in DM patients than in non-DM patients (7/382 vs. 9/2,191, respectively; P = 0.001; chi2= 10.64). All 16 patients with PR had received retrobulbar anesthesia (RA). RA was used in 61.21% of all surgeries and in 78.01% of the surgeries for DM patients. Occurrence of PR during RA was higher for DM patients than for non-DM patients (7/298 vs. 9/1,277, respectively; P = 0.011; chi2= 6.50). Mean operation times +/- SD for PR cases were 29.9 +/- 9.9 minutes and 38.2 +/- 5.3 minutes in DM and non-DM cases, respectively (P = 0.091). None of the photic lesions were sight threatening.

CONCLUSIONS

Diabetic patients may be more vulnerable to photic injury. Surgeons should take precautions to prevent PR when performing cataract surgery on diabetic patients.

Photochemical damage of the retina

Visual perception occurs when radiation with a wavelength between 400 and 760 nm reaches the retina. The retina has evolved to capture photons efficiently and initiate visual transduction. The retina, however, is vulnerable to damage by light, a vulnerability that has long been recognized. Photochemical damage has been widely studied, because it can cause retinal damage within the intensity range of natural light. Photochemical lesions are primarily located in the outer layers at the central region of the retina. Two classes of photochemical damage have been recognized: Class I damage, which is characterized by the rhodopsin action spectrum, is believed to be mediated by visual pigments, with the primary lesions located in the photoreceptors; whereas Class II damage is generally confined to the retinal pigment epithelium. The action spectrum peaks in the short wavelength region, providing the basis for the concept of blue light hazard. Several factors can modify the susceptibility of the retina to photochemical damage. Photochemical mechanisms, in particular mechanisms that arise from illumination with blue light, are responsible for solar retinitis and for iatrogenic retinal insult from ophthalmological instruments. Further, blue light may play a role in the pathogenesis of age-related macular degeneration. Laboratory studies have suggested that photochemical damage includes oxidative events. Retinal cells die by apoptosis in response to photic injury, and the process of cell death is operated by diverse damaging mechanisms. Modern molecular biology techniques help to study in-depth the basic mechanism of photochemical damage of the retina and to develop strategies of neuroprotection.

Bilateral retinal phototoxic injury during cataract surgery in a child

The intense illumination of the operating microscope has been implicated in photic retinopathy in patients and in animal studies. We report a case of bilateral macular phototoxicity occurring in an eleven-year-old child who underwent bilateral cataract surgery for radiation cataracts. We are unaware of other reports of retinal toxicity occurring during pediatric cataract surgery. We hypothesize that this child may have been predisposed to macular injury because of previous chemotherapy and radiotherapy exposure. Ophthalmic surgeons should be aware that light toxicity from the operating microscope might also occur in the pediatric population.

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.

Comparison of outcomes of primary and secondary implantation of scleral fixated posterior chamber intraocular lens

AIM

To assess and compare the results of primary and secondary implantation of scleral fixated posterior chamber intraocular lens (SFIOL).

METHODS

The medical records of a consecutive series of 55 eyes of 55 patients with SFIOLs implanted during (group 1) or after (group 2) complicated senile cataract surgery were retrospectively reviewed and analysed.

RESULTS

There were 30 and 25 eyes in group 1 and 2, respectively. Follow up was from 6 to 36 months. Mean logMAR postoperative best corrected visual acuity in group 1 was not significantly different (0.50 (SD 0.36)) from that of group 2 (0.36 (0.21)) (p=0.109). Postoperative best corrected visual acuity of 6/12 or better was achieved in 58.6% and 76.0% in group 1 and 2, respectively. The difference was not statistically significant (p=0.177). In group 1, 25 (83.3%) eyes had a total of 55 early complications, while in group 2, 16 (64%) eyes had 26 early complications (p=0.028). The difference in early complication was statistically significant. For late complication after 1 month, 21 (70.0%) eyes had a total of 37 complications in group 1, while 13 eyes (52.0%) had 19 complications in group 2 (p=0.077). The difference in late complication was not statistically significant.

CONCLUSION

Secondary implantation of SFIOL after cataract extraction seems to have a lower early complication rate than primary implantation in complicated cataract extraction although the final visual acuity and late complication rate are not significantly different.

Microscope-induced retinal phototoxicity in cataract surgery of short duration

OBJECTIVE

Microscope-induced retinal phototoxicity has been described after prolonged cataract surgery, usually in operations lasting longer than 100 minutes. The purpose of this study was to compare the features of microscope-induced retinal phototoxicity occurring in patients who underwent cataract surgery of short duration and long duration.

DESIGN

A retrospective nonrandomized comparative trial.

PARTICIPANTS

Thirty-four patients, whose medical records documented the development of phototoxic lesions in the retina as a result of cataract surgery, were divided into two groups: group A with 14 patients whose operating time was 30 minutes or less, and group B with 20 patients whose operating time was greater than 30 minutes.

INTERVENTION

All patients underwent either phacoemulsification or extracapsular cataract extraction (ECCE) with implantation of an intraocular lens.

RESULTS

The mean operating time was 23.1 minutes (range, 11-30 minutes) in group A, and 60.8 minutes (range, 34-123 minutes) in group B. Phacoemulsification was done more often in group A (P = 0.001) and ECCE in group B (P = 0.0003). A final refraction of +/- 1 D was achieved by 12 eyes (86%) in group A and by 12 eyes (60%) in group B (P = 0.11). The correlation between final refraction and duration of the operation was significant; the closer the final refraction approached to emmetropia, the shorter the duration of surgery (r = 0.53; P = 0.001). Diabetic retinopathy was more common in group A (P = 0.03).

CONCLUSIONS

Phototoxic lesions of the retina may occur during cataract surgery even when the duration of the operation is short. The most relevant associated factors found in this study were correction approximating emmetropia and diabetic retinopathy.

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.

Retinal photodamage

The retina represents a paradox, in that, while light and oxygen are essential for vision, these conditions also favour the formation of reactive oxygen species leading to photochemical damage to the retina. Such light damage seems to be multi-factorial and is dependent on the photoreactivity of a variety of chromophores (e.g., vitamin A metabolites, lipofuscin, melanin, flavins, porphyrins, carotenoids) endogenous to the retina. The aim of this article is to provide a detailed review of our current understanding of the photochemistry and photobiology of these chromophores and to consider how they may contribute to retinal ageing and pathology.

Is scleral fixation a safe procedure for intraocular lens implantation?

PURPOSE

No consensus currently exists on the optimal method for intraocular (IOL) implantation without capsular support. We evaluated the outcome and angiographic findings of eyes that underwent the implantation of scleral fixated IOLs.

METHODS

Iris and retinal fluorescein angiography were performed in 13 eyes that had received posterior chamber IOL implantation with scleral fixation. Follow-up examinations also assessed visual acuity (VA), intraocular pressure (IOP), IOL decentration and complications related to the procedure.

RESULTS

Mean visual acuity was 0.29 preoperatively and 0.71 postoperatively after a mean follow-up of 14.2 months. A best corrected visual acuity of 0.5 or better was obtained in 12 eyes. Iris fluorescein angiography did not show major vascular abnormalities. Retinal angiography showed 5 cases of macular edema. In 6 eyes light-induced retinal lesions occurred. Cellophane maculopathy was disclosed in 4 eyes. Macular edema was associated with photic injury in 4 cases and with cellophane maculopathy in 2 cases. Mean postoperative visual acuity was 0.6 in eyes with macular edema and 0.88 in eyes without (SD 0.18; range 0.5-1.0). Four of 5 eyes with macular edema had a postoperative visual acuity of 0.5 or better. There was no evidence of persistent IOP elevation or IOL decentration. No serious complications were recorded during surgery.

CONCLUSIONS

Transscleral fixation of posterior chamber IOLs provides adequate visual acuity in most patients. Macular edema was frequently associated with the procedure. Although this complication was a cause of low visual recovery after implantation, the majority of eyes with macular edema achieved a visual acuity of 0.5 or better. Light-induced retinal injury was a permanent complication.

Photic maculopathy after pterygium excision

PURPOSE

To report a patient who developed photic maculopathy after pterygium removal.

METHODS

A 27-year-old woman underwent pterygium removal with a conjunctival autograft after administration of retrobulbar anesthesia. A coaxial operating microscope was used, with an estimated retinal exposure of approximately 40 minutes.

RESULTS

On the first postoperative day, the patient noted a paracentral scotoma. A fluorescein angiogram on the fourth postoperative day documented a phototoxic lesion in the macula.

CONCLUSIONS

Phototoxic injury to the macula may occur after pterygium removal. Ophthalmologists should take precautions to minimize prolonged intense coaxial illumination of the retina while performing any ocular microsurgery.

Temporal sequence of changes in rat retina after UV-A and blue light exposure

Two spectral types of retinal light damage were induced in pigmented rats by irradiating small retinal patches at either 380 or 470 nm. The temporal sequence of changes in the retina was followed for up to 2 months by funduscopy and histology. For both damage types, fundus changes were best visible after 3 days. Histology showed that 380 nm specifically damaged photoreceptor cells, particularly the rods. All cell compartments of the rods, including the nucleus were affected already after 3 h. In the next days, damaged rods degenerated. At high doses (2.5 x the funduscopic threshold dose) all rods in the irradiated area were lost, resulting in a local photoreceptor lesion, which was still present at 2 months after the irradiation. At 470 nm, damage occurred both in the photoreceptor layer and in the pigment epithelium. Acute changes, at 1 h after irradiation, consisted mainly of damaged mitochondria in these layers. Next, the pigment epithelium showed swelling, an altered melanin distribution and, at high doses (2.5 x threshold), interruptions of the monolayer. Degeneration of photoreceptor cells was initially limited to a few scattered cells, but 3 days after high doses focal areas of massive degeneration were seen. At late stages, the cells of the pigment epithelium recovered and the photoreceptor layer showed a loss of cells. The results show that the spectral damage types are distinct in the early phases, indicating that different mechanisms are involved. Yet, the end effect of both damage types after exposure at doses up to 2.5 x the funduscopic threshold is remarkably similar and consists of local photoreceptor lesions.

Optical radiation safety of medical light sources

The phototoxicity of medical ultraviolet (UV) sources used in dermatology has long been recognized. Less obvious are potential hazards to the eye and skin from many other optical sources-both to the patient and to the health-care worker. To assess potential hazards, one must consider not only the optical and radiometric parameters of the optical source in question but also the geometrical exposure factors. This knowledge is required to accurately determine the irradiances (dose rates) to exposed tissues. Both photochemically and thermally induced damage are possible from intense light sources used in medicine and surgery; however, thermal injury is rare unless the light source is pulsed or nearly in contact with tissue. Generally, photochemical interaction mechanisms are most pronounced at short wavelengths (UV) where photon energies are greatest, and also will be most readily observed for lengthy exposure durations.

Prospective incidence of photic maculopathy after cataract surgery

PURPOSE/METHODS

To determine the incidence of photic retinal injury during cataract surgery, we studied 37 consecutive patients with intravenous fluorescein angiography within ten days after cataract surgery. The microscope irradiance was standardized for all cases.

RESULTS/CONCLUSIONS

Fluorescein evidence of photic retinal injury did not develop in any of the 37 cataract patients. Incidence rates for photic retinal injury induced by the surgical microscope vary considerably among ophthalmologists and most likely reflect differences in microscope brightness, surgical duration, and surgical technique.