Multipurpose Conical Orbital Implant in Evisceration

PURPOSE

To evaluate the safety and efficacy of the porous polyethylene multipurpose conical orbital implant for use in evisceration.

METHODS

A retrospective review of 31 eyes that underwent evisceration and received the multipurpose conical orbital implant. The orbits were evaluated at 1 week, 1 month, and 6 months after final prosthetic fitting for implant exposure, superior sulcus deformity, and prosthetic motility.

RESULTS

There were no cases of extrusion, migration, or infection. All patients had a good cosmetic result after final prosthetic fitting. Prosthetic motility was good in all patients. Exposure developed in one eye (3%) and a superior sulcus deformity developed in one eye (3%).

CONCLUSIONS

Placement of an multipurpose conical orbital implant in conjunction with evisceration is a safe and effective treatment for blind painful eye that achieves good motility and a good cosmetic result.

Image Processing Strategies Dedicated to Visual Cortical Stimulators: A Survey

Multi-electrode devices are constantly evolving toward a state where complexity and reliability are adequate for providing a breakthrough in visual cortical stimulation allowing the blind to recover partial vision. Yet few research teams have focused on the development of the front-end subsystem that transforms an input image from a camera into stimulation commands. This article collects state-of-the-art knowledge about the appearance and organization of phosphenes, and previous work in image processing dedicated to visual cortical stimulation. Observations and hypothesis about important issues are highlighted, and six image processing strategies that could be used in such a subsystem are presented, from the most optimistic that use brightness modulation to emulate grayscale to the most conservative that use only on/off phosphene evocation.

Surgical reversal of prolonged blindness from a metastatic neuroblastoma

BACKGROUND

Reports of tumor-related anterior visual pathway blindness that have resolved after surgical decompression are rare. The longest reported duration of tumor-related blindness completely reversed by optic nerve decompression is 3 days. We describe a pediatric patient with 7 days of no light perception who experienced reversal of blindness following tumor resection and optic nerve decompression.

CASE DESCRIPTION

A 33-month-old boy presented with a 4-day history of no light perception. Magnetic resonance imaging revealed a mass involving the sphenoid sinus, sella turcica, and clivus with significant optic nerve involvement. Loss of light perception and complete absence of a pupillary light reflex were documented for the next 72 h. A sluggish pupillary light reflex was regained 24 h after instituting intravenous steroids. An urgent bi-frontal craniotomy and optic nerve decompression were performed 7 days after the onset of blindness. Surgical pathology revealed metastatic neuroblastoma. Eleven days after optic nerve decompression, the child was able to count fingers and recognize faces and printed book characters.

CONCLUSION

Prolonged blindness secondary to tumor-related optic nerve compression may be reversible up to 1 week from onset in children presenting with no light perception.

Stem cells to replace the optic nerve

Methods that exist now and that might be developed are suggested to replace retinal ganglion cells and their axons in the optic nerve, ultimately to re-establish functional vision in eyes blind from glaucoma.

Visual outcome of blind eyes in pituitary apoplexy after transsphenoidal surgery: a series of 14 eyes

BACKGROUND

To study the visual outcome of patients who became blind after an episode of pituitary apoplexy and who subsequently underwent emergency transsphenoidal decompression of the optic apparatus, and to identify factors that may have a bearing on the visual outcome in such patients.

METHODS

Twenty-three patients underwent transsphenoidal surgery for pituitary apoplexy over a 5-year period at the All India Institute of Medical Sciences. Among them, 8 (35%) presented with visual deterioration to monocular (n = 2) or binocular (n = 6) blindness after the apoplectic episode. There were 7 males and 1 female with the average age of patients being 43 years. The mean delay between the apoplexy and neurosurgical consultation was 10 days, with a range of 4 to 30 days. The adenoma was classified as "giant" in 4 and multicompartmental in 2 patients. After surgery, all patients had a minimum follow-up of 3 months.

RESULTS

Four patients (50%) had improvement in vision to greater than 2/60 (Snellen's), including 2 patients whose vision improved to 6/6. All patients in whom there was improvement in vision had been operated on within a week of the apoplectic episode.

CONCLUSIONS

This study shows that even completely blind eyes may have remarkable improvement in vision if surgical decompression of the optic apparatus is undertaken early. Awareness regarding pituitary apoplexy and reversibility of vision loss needs to be increased among the medical community, especially ophthalmologists and physicians, so that timely neurosurgical intervention can occur.

Enucleation versus evisceration

The choice of enucleation and evisceration for removal of an eye remains controversial in certain circumstances. An international panel was asked to give their surgical management of two clinical cases that require either enucleation or evisceration. Case one follows multiple vitreoretinal procedures, and the risk of sympathetic ophthalmia is considered in the surgical management. Case two has had postoperative endophthalmitis, and the possibility of implant infection following insertion of an orbital implant with evisceration and enucleation is discussed.

Outcome of corneal transplantation

Corneal transplantation is a sight restoring surgery done for corneal blindness. The purpose of this retrospective preliminary study is to analyze the outcome of 54 corneal transplantations (for 32 females and 22 males) done in the Department of Ophthalmology between September 1998 and June 2002. The mean follow-up period was 13 months. Hundred percent (6/6) of the keratoconus (KC) and 85.4% of the nonkeratoconus grafts survived at a mean duration of 7.1 months and 16 months respectively. Seven of the 54 grafts (13%) have failed. The causes of graft failure were graft rejction in 4 and bacterial keratitis in 3 cases. Fifty of the 54 cases (92.6%) had a preoperative visual acuity of < 3/60. As a result of the transplantation, the percentage of blind eyes dropped from 92.6% to 21%. The data in this study confirms that corneal transplantation is a reasonably successful procedure in restoring sight for seleted cases of corneal blindness in Ethiopia.

Penetrating orbitocranial gunshot injuries

BACKGROUND

The aim of this study was to analyze the effect of a surgical management protocol and other important clinical features on the prognosis of patients who had penetrating orbitocranial gunshot injuries.

METHODS

Thirty-five patients (30 unilateral, 5 bilateral) who had penetrating orbitocranial gunshot injuries were analyzed. The wounds were mainly caused by shrapnel fragments or bullets. Craniotomy was the standard treatment in all patients. Investigated clinical features included Glasgow Coma Scale (GCS) score on admission, the mode and the extent of brain injury, and the presence of an intracranial retained foreign body. The prognostic importance of complications such as infection, intracranial hemorrhage, cerebrospinal fluid leak, and epileptic seizures was also investigated. The mechanism and the injury characteristics of the patients were evaluated by predicting the visual outcome of the victims according to a newer classification system as well as other variables pertinent to this specific clinical setting of severe eye trauma. Final visual acuities of the patients were also measured.

RESULTS

The outcome of 35 penetrating orbitocranial gunshot injured patients was as follows: death in 3 patients, vegetative state in 1, severe disability in 2, moderate disability in 2, and good recovery in 27 cases. Localization and extent of the injury and GCS score on admission were the most important indicator for good neurological outcome. The predictors for good visual outcome were type B, grade 1, zone I, and relative afferent pupillary defect-negative injuries. The predictors for poor outcome were type A, grade 5, zone III, and relative afferent pupillary defect-positive injuries.

CONCLUSION

The prognosis of the injury depends on the course of the bullet or shrapnel fragment and the interdisciplinary care. An extensive preoperative evaluation of penetrating orbital trauma and a combined ophthalmic and neurosurgical approach are recommended to minimize the morbidity of the patients. However, complete removal of the foreign material in a deep or ventricular localization is not mandatory because careful debridement and tight closure of dura provides desired outcome. Evaluation of trauma mechanism and injury characteristics according to the Ocular Trauma Classification System seems to predict accurately the visual outcomes in this series.

Diabetic retinopathy for general practitioners

The most significant complication of diabetes mellitus involves the eye and which develops 85% of all diabetics eventually to retinopathy. Diabetic retinopathy is the commonest cause of blindness between 4th and 7th decades. It is essentially a microangiopathy with two distinct stages during its evolution, the preclinical and clinical stages. Diabetic maculopathy is the commonest cause of visual loss in diabetics. Progression of the diseases can be retarded by early diagnosis and using appropriate measures. Well known risk factors are diabetes age, metabolic control of hypertension, associated renal disease and pregnancy. The management plan of the secondary level is early diagnosis and laser photocoagulation or surgical intervention. Vitreoretinal surgery is certainly of benefit in patients with advanced diabetic eye disease. The PROMPT factors can be applied to decrease diabetes mellitus related blindness.

Five year follow up of biocolonisable microporous fluorocarbon haptic (BIOKOP) keratoprosthesis implantation in patients with high risk of corneal graft failure

AIM

To study the anatomical and visual performance following implantation of a model of artificial cornea and to evaluate the postoperative long term complications.

METHODS

11 eyes of 11 patients with bilateral corneal blindness considered as potentially having high risk of failure of penetrating corneal keratoplasty were implanted with biocolonisable Kpro keratoprosthesis (BIOKOP I, FCI, Rantigny, France) in the period between January 1996 and May 1998. Only one eye was implanted in all patients and followed up for a period of 60 months. The visual outcome, anatomical and functional stability, complications, and the general performance of the keratoprosthesis were evaluated.

RESULTS

The keratoprosthesis (BIOKOP I) only 36.3% remained in position to date. In the patients' last visit five eyes (45.4%) were blind and one (9.0%) showed a slight improvement in the best corrected visual acuity (BCVA) in comparison to preoperative tests. Six eyes (54.5%) showed improved BCVA before having postoperative complications. Four eyes underwent replacement of a BIOKOP I Kpro with a BIOKOP II as a result of extrusion. The keratoprostheses remained anatomically in situ for a mean of 25.5 months and their functional performance period was limited to a mean of 22 months.

CONCLUSION

Corneal keratoprosthesis (BIOKOP I, II) does not provide a stable anatomical relation with the surrounding ocular structures. Its ability to restore vision is limited to a short postoperative period in eyes implanted with severe ocular surface disease.

Outcome of penetrating keratoplasty in patients with bilateral corneal blindness

PURPOSE

To evaluate the outcome of penetrating keratoplasty in patients with bilateral corneal blindness.

METHODS

Bilaterally blind patients who had undergone optical penetrating keratoplasty (PK) were evaluated on optical and refractive parameters and presence of complications if any. The results at 3 months, 6 months, and 1 year were compared with age-matched and indication-matched unilaterally blind controls.

RESULTS

The most common indication for surgery in both the groups was the presence of a corneoiridic scar. Best corrected visual acuity of > or =6/18 was seen in five (16.66%) patients in the study group and in 11 (36.66%) patients in the control group (P = 0.14). In all, 15 (50%) grafts in the study group and six (20%) in the control group failed (P = 0.03). The most common cause of failure was graft infection (40%) in the study group and post-PK glaucoma (20%) in the control group. The percentage of graft rejection as a cause of graft failure was the same in both the groups. A composite socioeconomic status scale based on family literacy and income suggested that 70% of the cases in the study group and 30% in the control group belonged to the low socioeconomic group (P = 0.004).

CONCLUSION

The outcome of optical penetrating keratoplasty in patients with bilaterally blinding corneal disease is poorer than those who are unilaterally blind. Low socioeconomic status may be a contributing factor for the poor outcome.

Retinal replacement--the development of microelectronic retinal prostheses--experience with subretinal implants and new aspects

BACKGROUND

Progress in the field of microelectronics has led to the development of visual prostheses for the treatment of blinding diseases. Different concepts of retinal replacement are currently under investigation. The aim of the retinal prostheses is to replace the function of lost photoreceptors in degenerative diseases, such as retinitis pigmentosa.

METHODS

Within the field of visual prosthetic developments mainly two retinal based concepts are under investigation. One of the concepts is the epiretinal implant which acquires images of an external camera and after preprocessing by a computer reading this visual information into the human visual system. In the subretinal prosthesis design concept an array of stimulation electrodes is placed in the subretinal space. True to the concept the image falling on the retina and its light impulses are converted into electrical currents by microphotodiodes and the retina is stimulated with these locally. To test the feasibility of the concepts the biocompatibility and to determine basic stimulation parameters a lot of animal experiments and first human experiments were carried out.

RESULTS

Currently the research conducted by teams in Germany, the USA and Japan into epiretinal and subretinal implants has reached the stage where clinical trials can now be performed. Individual pilot studies were carried out for both the epiretinal and the subretinal implant by different research groups.

DISCUSSION

The results achieved by the researchers indicate that cortical action potentials can be triggered by electric retinal stimulation with both concepts. The experimental work has highlighted a whole range of obstacles, not all of which have yet been fully resolved. These findings offer hope that coarse restoration of vision may be feasible by electrical stimulation.

Cosmetic globe surgery in the horse

Effects of traumatic injury or inflammation on the equine eye can be catastrophic. These ocular conditions can frequently result in blindness or chronic pain. In addition to blindness and pain, permanent unsightly cosmetic defects can occur. This article addresses options available for improved cosmetic outcome in horses with ocular scars or requiring enucleation. Many of these options have been described in detail previously. New information has been added to the discussion of each option where pertinent.

Enucleation versus preservation of blind eyes following plaque radiotherapy for choroidal melanoma

BACKGROUND

Currently available information about patients with posterior uveal melanoma treated by plaque radiotherapy is insufficient to determine what to do about eyes that become blind as a consequence of the tumour and its treatment. Should they be enucleated, or is ocular preservation just as good in terms of survival?

METHODS

We performed a retrospective survival analysis of secondary enucleation versus ocular preservation in patients with a posterior uveal melanoma treated by plaque radiotherapy whose irradiated eye became completely blind following that treatment. Of the 79 patients who fulfilled defined inclusion criteria, 25 underwent secondary enucleation of the blind eye, and 54 retained their irradiated blind eye.

RESULTS

Most of the baseline demographic and tumour-related variables evaluated were similarly distributed between the subgroups. The 5-year, 10-year and 15-year all-cause death rates in the secondary enucleation subgroup were 24.7%, 51.5% and 52.0% respectively, and those in the ocular preservation subgroup were 7.4%, 32.9% and 48.1% respectively. In spite of the apparent slight difference between the curves, the difference was not statistically significant (p = 0.41, Mantel-Haenszel test).

INTERPRETATION

Although a retrospective study of this type has several limitations, our results suggest that secondary enucleation is not likely to substantially improve survival of patients whose irradiated eye becomes totally blind following plaque radiotherapy for choroidal or ciliochoroidal melanoma.

Case payment and the adoption of new technology: an empirical study of cataract surgery in Taiwan

BACKGROUND

Case payment for cataract surgery with Government Employee Insurance (GEI) was implemented at Chang Gung Memorial Hospital (CGMH) in March 1994, and fee-for-service (FFS) was retained for cataract inpatients with or without other health insurance. We examined the impact of this change in the reimbursement policy from FFS to case payment on the health care provider's practice behavior towards a new emerging technology, using cataract surgery as an example.

METHODS

Secondary data analysis was performed using 1 year of CGMH data before (period 1, from March 1993 to February 1994) and after (period 2, from March 1994 to February 1995) implementing the new policy. Inpatient records for cataract surgery using either extracapsular cataract extraction (ECCE, the old technology) or phacoemulsification (Phaco, the new technology) were included. Logistic regression models were employed to assess how case payment affected the health care provider's adoption of new technology.

RESULTS

The percentage of cases treated using the new Phaco technology grew from period 1 (6.6%) to period 2 (23.6%) among all 4 study groups, despite Phaco being more expensive than ECCE. More importantly, the increment ratio of Phaco use from periods 1 to 2 was the smallest for GEI patients (3.26-fold) when compared with the other 3 groups (4.16-5.29-fold).

CONCLUSIONS

Both new technology and cost containment strategies should be taken into account when setting up a reimbursement policy.

[Blindness after nitrous oxide anesthesia and internal gas tamponade]

The authors describe the case of a patient with bilateral retinal detachment. Immediately after surgery for the second eye under general anesthesia with nitrous oxide, the patient reported severe visual loss in the first eye successfully treated surgically 2 weeks before, with a residual gas bubble (C3F8) of 50%. In this case, nitrous oxide had rapidly entered the gas bubble and induced a transient expansion of the gas tamponade with a dramatic increase in intraocular pressure. The consequence was a central retinal artery occlusion, which resulted in irreparable ischemic retinal damage and blindness, explaining the severe and sudden visual loss. Nitrous oxide is regularly used but contraindicated if intraocular gas is present, due to its potential threat to visual function. We suggest that patients anesthetized with nitrous oxide carry a card or a bracelet detailing the risks of intraocular gas tamponades combined with nitrous oxide and with travel to high altitudes. This would inform not only patients but also medical personnel caring for these patients.