Krypton red laser photocoagulation of the ocular fundus. 1982

The theoretical rationale, the histopathologic evidence, and the preliminary clinical studies related to krypton red laser (KRL) photocoagulation of the ocular fundus are reviewed. The authors report on their experience with currently available laser systems using this wavelength (647.1 nm) for photocoagulation of retinal vascular proliferative diseases and chorioretinal diseases associated with exudative manifestations. A histopathologic and clinical comparison of argon blue-green laser (ABGL), the pure argon green laser (AGL), and the krypton yellow laser (KYL), with reference to photocoagulation treatment of the ocular fundus is also discussed.

The Retina in Forensic Medicine

The retina reflects a variety of diseases in the living patient. However, the retina is not routinely examined in deceased persons, and therefore it is unknown if routine retinal examination would be a useful adjunct to the forensic autopsy. To examine this issue, the retinae of routine medical examiner cases were examined utilizing an ophthalmic endoscope. The results of the first 100 examinations are reported. Specific attention was given to changes that reflected the postmortem interval, the development of petechiae as related to cardiopulmonary resuscitation, and the association of retinal hemorrhages to subconjunctival hemorrhages. The procedure was helpful in cases of suspected shaken baby syndrome, exsanguination, and carbon monoxide poisoning and in cases with sudden increased intracranial pressure (Terson syndrome). It appears that lividity patterns exist in the retina, and this may be potentially useful in determining body position after death. Some natural disease processes, such as hypertension, were also identified. Finally, the utility of the ophthalmic endoscope as a means of circumventing the problem of corneal clouding is discussed, and ideas for further research using this technology are presented.

Management of macular holes that develop after retinal detachment repair

PURPOSE

To study the characteristics and management of macular holes that develop after prior rhegmatogenous retinal detachment (RD) repair.

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

The setting was a clinical practice. The case records of all of our patients (n = 12) who developed a new full-thickness macular hole after prior RD repair over an 8-year period were examined. Patients who developed a macular hole after prior RD repair were offered either surgical repair of the macular hole or continued observation. For eyes that underwent macular hole repair, main outcome measures included macular attachment status and postoperative visual acuity.

RESULTS

Twelve full-thickness macular holes were detected in a series of 2,380 eyes (0.5% prevalence), which had undergone surgery for prior primary RD. Ten macular holes developed after scleral buckling surgery, two after pneumatic retinopexy, and none were seen after primary vitrectomy. The fovea had been detached in 11 of the 12 eyes at the time of RD. The median time to macular hole diagnosis after RD repair was 3.4 months (range, 0.3-161 months). Eight of the eight eyes (100%) undergoing surgical repair achieved macular reattachment with a median of 3.5 lines of visual improvement at a median of 14.8 months of follow-up. Seven of these eight eyes had an improvement in visual acuity of at least 3 Snellen lines, and four of the eight had at least 20/40 visual acuity postoperatively. Four eyes with macular holes were observed.

CONCLUSIONS

Macular holes developed in less than 1% of eyes that had previously undergone repair of rhegmatogenous RD. In our series, these atypical holes were seen predominantly after macula-off detachments, most commonly occurring after scleral buckling procedures. They were effectively repaired using conventional pars plana vitrectomy with long-acting gas tamponade and a variety of adjuvant therapies. A good visual outcome is possible with this approach.

Lacquer cracks following laser treatment of choroidal neovascularization in pathologic myopia

BACKGROUND

Lacquer cracks are breaks in the retinal pigment epithelial-Bruch's membrane-choriocapillaris complex and are manifestations of pathologic myopia. Progressive posterior segment elongation, uveal scleral thinning, and retinal pigment epithelial degeneration are thought to create a predisposition for crack formation in these eyes. In turn, choroidal neovascularization (CNV) may develop within the cracks to produce disciform scarring of the macula. This study examined lacquer cracks as a possible consequence of laser photocoagulation of CNV.

METHODS

From the files of two retinal referral practices, five patients were located in whom lacquer cracks developed or expanded after laser photocoagulation for macular CNV in pathologic myopia. The mean age of the patients was 54.8 years. Four patients were treated with krypton red laser and one with an argon laser. Laser settings were available for only one of the patients.

RESULTS

After laser photocoagulation, lacquer cracks were noted to expand in one or two directions from the laser scar between 10 days and 3 months of the treatment. The cracks also served as a pathway for progressive or recurrent neovascularization.

CONCLUSIONS

Although lacquer cracks occur spontaneously in pathologic myopia, expansion, elongation, or simple development of a crack may occur as a result of laser photocoagulation of CNV. The new cracks also serve as a potential risk for recurrent neovascularization. This potential adverse complication should be considered in the management of CNV in pathologic myopia with laser treatment.

Microwave cyclodestruction: evaluation on human eyes

AIMS

The study was set up to evaluate the effect of microwave cyclodestruction on human eyes.

METHODS

Two human eyes were studied. For treatment a horn shaped 5.8 GHz microwave applicator and fibre optic thermometry were used. Just before enucleation, the rectangular (2 x 3 mm) microwave aperture was placed onto the conjunctiva at a position 1-2 mm posterior to the corneal scleral limbus. Each of three to four treatment spots was targeted to receive a thermal dose of 54 degrees C for 1 minute. Clinical, gross, and histopathological evaluations were performed.

RESULTS

Clinical evaluations of the treatment sites (immediately after microwave application) revealed no evidence of conjunctival or scleral damage. Trace fluorescein 2% uptake was noted within the targeted zones. The first eye was sectioned along the equatorial axis. Examination of the ciliary body and pars plana revealed whitening of the ciliary processes and depigmentation. Histopathological evaluations revealed ciliary epithelial necrosis with pigment dispersion. The vascularity of the ciliary processes showed focal disruption and haemorrhage. The underlying ciliary muscle and sclera appeared to be unaffected. No other findings could be attributed to microwave cyclodestruction.

CONCLUSION

The results of this phase I toxicity study suggest that microwave heating can be used to damage preferentially the epithelial layers of the human ciliary body.

Management of dislocated nuclear fragments after phacoemulsification

We examined 13 patients referred for management of dislocated lens fragments after phacoemulsification. Ocular findings included corneal decompensation, glaucoma, inflammation, and retinal tears and detachments. Eleven of the 13 patients underwent vitrectomy with removal of lens fragments. Surgical indications included the presence of large lens fragments, uncontrolled glaucoma, persistent and severe inflammation, and retinal detachment. Better visual acuity was observed in patients who had smaller lens fragments or when vitrectomy was delayed to allow medical treatment of intraocular inflammation and glaucoma. The results indicate that nucleus dislocation during phacoemulsification is an important visual complication, with seven of the 13 patients having a final visual acuity of 20/80 or less.

Management of macular puckers associated with retinal angiomas

Monocular visual loss in four patients was caused by epiretinal macular membranes associated with peripheral retinal capillary angiomas or angioma-like lesions. Three patients had solitary vascular lesions and one had two discrete vascular lesions. All patients were in good health, with no evidence of the von Hippel-Lindau syndrome. In three patients, spontaneous peeling of the macular membranes and visual improvement occurred 2 to 6 months after obliteration of the angioma-like lesions with cryotherapy (two patients), or cryotherapy combined with argon laser (one patient). The fourth patient underwent a vitrectomy 8 months after the macular pucker had failed to respond to treatment of the vascular lesion.

Perfluoropropane gas, modified panretinal photocoagulation, and vitrectomy in the management of severe proliferative vitreoretinopathy

Seventy-six consecutive patients with total rhegmatogenous retinal detachments and severe proliferative vitreoretinopathy underwent combined pars plana vitrectomy, lensectomy, panretinal photocoagulation, perfluoropropane gas (C3F8)/fluid exchange, and scleral buckling. Sixty-two (82%) of the patients had successful, sustained (greater than 12 months) posterior retinal reattachments at last examination. Of these 62 patients, 40 (65%) had complete retinal attachment, with no evidence of regrowth of periretinal membranes or redetachments following the initial procedure. In the remaining 22 cases with successful reattachment of the retina posterior to the equator, partial peripheral retinal detachments were observed. In 16 of the 22 cases, the detachments occurred entirely anterior to the boundary of the previously placed photocoagulation lesions. The posterior retina remained uninvolved, and no further treatment was needed. Reoperation was required in the other six patients to achieve sustained posterior retinal reattachment. Postoperative visual acuity ranged from 20/40 to bare light perception, with 69% of the anatomically successful cases obtaining functional visual acuity (greater than 20/400). Failures were related to reproliferation of fibrous membranes.

Acute frosted retinal periphlebitis

We examined three previously healthy young patients who suffered acute visual loss associated with diffuse bilateral retinal periphlebitis. Each patient developed thick, inflammatory infiltrates surrounding all of the retinal veins, creating the appearance of frosted tree branches. Initial visual acuities ranged from 20/20 to hand motions (median, counting fingers). All patients showed rapid improvement after starting oral corticosteroid therapy, and all but one of the six affected eyes regained a visual acuity of 20/20. The clinical appearance and course of these patients matched those of a condition previously described in Japan and labeled frosted branch angiitis. The term "acute frosted retinal periphlebitis" seems to describe more accurately the clinical findings.

Treatment of experimental methicillin-resistant Staphylococcus epidermidis endophthalmitis with intravitreal vancomycin

Endophthalmitis remains a dreaded complication of intraocular surgery and penetrating eye trauma. Subconjunctival, topical, and systemic antibiotics have been largely ineffective in the treatment of endophthalmitis, whereas intravitreal antibiotics have proved efficacious. Methicillin-resistant Staphylococcus epidermidis has become an important pathogen in many infections, including endophthalmitis. Toxicity, clearance, and efficacy of intravitreal vancomycin were evaluated in the treatment of experimental methicillin-resistant S. epidermidis endophthalmitis. No evidence of retinal toxicity was found and therapeutic levels were demonstrated six days after injection. The treated rabbit eyes showed a marked beneficial effect when compared to the untreated eyes. If experience confirms the safety of intravitreal vancomycin in human eyes, vancomycin should be considered the drug of choice for methicillin-resistant S. epidermidis endophthalmitis.

Krypton red laser photocoagulation for subretinal neovascularization

One hundred fifty-seven patients with subretinal neovascularization (SRN) were treated in a prospective, nonrandomized, consecutive study with the krypton red laser (KRL). The patients were analyzed with respect to age, etiology of the SRN, location of the SRN, and pre- and post-treatment visual acuity in patients with at least three months follow-up. Previous studies have not investigated KRL photocoagulation within the foveal avascular zone (FAZ). The results of this study compare favorably with other large series in which patients with SRN located outside the FAZ were treated with the argon blue-green laser (ABGL).

Recurrent subretinal neovascularization

A retrospective analysis of a consecutive series of patients treated with krypton red laser (KRL) photocoagulation for subretinal neovascularization (SRN) secondary to drusen-related macular degeneration (DMD) was carried out to investigate the frequency and nature of recurrent neovascularization (recurrence). A classification of various types of recurrences based on the clinical and fluorescein angiographic features and the onset of their appearance in the postoperative course was used in this study. Patient, fundus, and membrane variables were examined in search of relevant high risk factors predisposing to recurrences. The membrane's proximity to the fovea and its relative lack of pigmentation were individual factors which were associated with a high risk of recurrence (P less than 0.05 for distance and P = 0.005 for color). Multivariate analysis also indicated that a greater distance from the fovea (P less than 0.05) and a darker color (P = 0.002) were favorable features to the primary membrane, reducing the probability of a recurrence. Overall, 39% of the patients experienced recurrences (23% of the patients had treatable recurrences and 16% had non-treatable recurrences extending under the center of the fovea). The membranes recurred predominantly at the margin of the photocoagulation burn. The recurrences were also noted relatively early in the postoperative course, 65% within two months after photocoagulation of the primary membrane. The fluorescein angiographic and clinical nature of these membranes and the visual effect of retreatment are also discussed in the paper.

Peripheral retinal detachments and retinal pigment epithelial atrophic tracts secondary to central serous pigment epitheliopathy

Twenty-five patients with central serous pigment epitheliopathy (CSP), also known as central serous chorioretinopathy, have been observed to have inferior hemispheric retinal pigment epithelial atrophic tracts, presumptive of antecedent retinal detachments. Five of these patients were noted to have clinically discernible, dependent peripheral retinal detachments. The clinical and fluorescein angiographic features of these patients are reviewed. Alterations in the retina, the retinal pigment epithelium (RPE) and the choroid are also described. They include the commonly associated manifestations of CSP such as RPE leaks and macular detachment as well as some newly recognized disturbances such as retinal capillary dilatation (telangiectasia), retinal capillary leakage, retinal lipid deposition, cystoid macular edema, choriocapillaris atrophy, choroidal neovascularization and disciform scarring.

The microsurgical management of giant retinal tears with trans-scleral retinal sutures

Eight cases of retinal detachment from giant tears were followed from four months to two years. Patients were treated with a combined procedure, including pars plana vitrectomy, rotation of the patient with air-gas fluid exchange to bring the retina into its normal anatomic position, and trans-scleral retinal sutures, using an external rather than internal approach. Seven of the eight cases were reattached successfully. Methods, materials, and complications are described. Pre- and post-operative information regarding visual acuity and results are listed in tabular form.

Bilateral ocular melanocytosis with malignant melanoma of the choroid

A woman with bilateral ocular melanocytosis developed a malignant melanoma of the choroid in one eye. The ocular melanotic hyperpigmentation, present since childhood, clinically involved the conjunctiva and episcleral and uveal tract of both eyes. To our knowledge this is only the second reported case of a uveal malignant melanoma in a patient with bilateral ocular melanocytosis. There is evidence that patients with ocular of oculodermal melanocytosis have an increased incidence of malignant melanoma of the uvea. It is possible that patients with bilateral ocular melanocytosis have a greater chance of developing of uveal malignant melanoma than do those with unilateral involvement.