Retinal detachment in the cat: the pigment epithelial-photoreceptor interface

Twenty-six cat retinae were surgically detached by injecting fluid into the subretinal space (SRS). The retinae were then studied by light and electron microscopy at detachment intervals ranging from 1/2 hr to 14 months. Degenerative and proliferative changes occur at the retinal pigment epithelial (RPE)-photoreceptor interface very soon after detachment, and the severity of these changes depends upon both the duration and height of the detachment. The specialized apical RPE processes that ensheath the outer segments are replaced by a uniform fringe of short, undifferentiated processes. The apical RPE surface becomes mounded, and this mounding becomes more pronounced at longer detachment durations. Labeling experiments with 3H-thymidine showed that some cat RPE cells enter a phase of stimulated DNA synthesis 12-24 hrs after detachment; RPE mitotic figures are first apparent 48 hrs after detachment. In the cat, discrete regions of proliferated RPE cells usually appear in one of several configurations. A number of different cell types, including polymorphonuclear neutrophils, monocytes at various maturational stages, photoreceptor cells, Müller cells, and RPE cells, appear in the expanded SRS of detached retinae. Rod and cone outer segments degenerate rapidly and become membrane bound sacs by 3 days postdetachment; the assembly of new outer segment membrane apparently does not stop completely even at moderately long detachment intervals (ie, 2 months). Degenerative changes in the inner segments do not take place with the same rapidity as those in the outer segments. The changes that occur at the RPE-photoreceptor interface are rapid, progressive, and sometimes irreversible events that have significant implications for photoreceptor recovery following retinal reattachment surgery.     

Retinal ganglion cell-inner plexiform and nerve fiber layers in neuromyelitis optica

AIM: To determine the thickness of the retinal ganglion cell-inner plexiform layer (GCIPL) and the retinal nerve fiber layer (RNFL) in patients with neuromyelitis optica (NMO). METHODS: We conducted a cross-sectional study that included 30 NMO patients with a total of 60 eyes. Based on the presence or absence of optic neuritis (ON), subjects were divided into either the NMO-ON group (30 eyes) or the NMO-ON contra group (10 eyes). A detailed ophthalmologic examination was performed for each group; subsequently, the GCIPL and the RNFL were measured using high-definition optical coherence tomography (OCT). RESULTS: In the NMO-ON group, the mean GCIPL thickness was 69.28±21.12 μm, the minimum GCIPL thickness was 66.02±10.02 μm, and the RNFL thickness were 109.33±11.23, 110.47±3.10, 64.92±12.71 and 71.21±50.22 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the NMO-ON contra group, the mean GCIPL thickness was 85.12±17.09 μm, the minimum GCIPL thickness was 25.39±25.1 μm, and the RNFL thicknesses were 148.33±23.22, 126.36±23.45, 82.21±22.30 and 83.36±31.28 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the control group, the mean GCIPL thickness was 86.98±22.37 μm, the minimum GCIPL thickness was 85.28±10.75 μm, and the RNFL thicknesses were 150.22±22.73, 154.79±60.23, 82.33±7.01 and 85.62±13.81 μm in the superior, inferior, temporal and nasal quadrants, respectively. The GCIPL and RNFL were thinner in the NMO-ON contra group than in the control group (P<0.05); additionally, the RNFL was thinner in the inferior quadrant in the NMO-ON group than in the control group (P<0.05). Significant correlations were observed between the GCIPL and RNFL thickness measurements as well as between thickness measurements and the two visual field parameters of mean deviation (MD) and corrected pattern standard deviation (PSD) in the NMO-ON group (P<0.05). CONCLUSION: The thickness of the GCIPL and RNFL, as measured using OCT, may indicate optic nerve damage in patients with NMO.     

Quantitative aspects of synaptic ribbon formation in the outer plexiform layer of the developing cat retina

The development of synaptic ribbons in rod and cone photoreceptor terminals of the cat retina was studied using quantitative electron microscopy. At the region of the area centralis, synaptic ribbon profiles are initially recognized at PCD (postconception day) 59. Synaptic ribbon density increases rapidly, reaching a peak of 0.55 ribbons/micron 3 at PCD 68 (postnatal day 3) and maintains approximately that value for an additional 8 d. Following PCD 76, ribbon density begins to decrease, to 0.37 ribbons/microns 3 at PCD 82 and 0.25 ribbons/microns 3 at PCD 102. Although ribbon density drops by approximately 50% during this 39-d period, the outer plexiform layer (OPL) volume at the area centralis increases by about 20%. Ribbon density continues to decrease gradually over a protracted period to reach a final adult value of 0.11-0.14 ribbons/microns 3. During the period of high ribbon density, rod spherules with two, or even three ribbon profiles, were routinely observed. In contrast, in the adult, spherules with more than one ribbon profile are only rarely encountered. During development, the length of synaptic ribbon profiles increases from a mean of 0.22 microns at PCD 62 to the 0.47 microns mean length found in the adult.     

Retinal detachment in pseudophakia

In a group of 2,281 eyes after extraction of a cataract and implantation of an iris clip lens (1,362 eyes after intracapsular extraction and 927 eyes after extracapsular extraction) motion of the retina occurred in 36 eyes (1.67%), incl. 27 after intracapsular extractions (1.98%) and 9 after extracapsular extractions (0.97%). In patients with pseudophakic retinal detachment after implantation of an iris clip lens the frequency of factors which might interfere with the development of this complication was investigated. The latter proved to be the following: prolapse of the vitreous body, luxation of the implanted lens, posterior uveitis and myopia. Detachment of the retina was preceded by: peroperative prolapse of the vitreous body in 34.21%, luxation of the implanted lens in 28.95%, posterior uveitis in 36.85% and myopia (up to -4.0 Ds) in 21.05%. Anatomical and functional results after operation of pseudophakic motion were evaluated in 38 eyes (36 eyes operated on account of cataract in the authors' department, two in other departments). The minimal follow up period after operation of retinal detachment was six months. Anatomical restoration of the retina was achieved in 23 eyes (60.53%), in 9 eyes a residual motion remained (23.68%) and in four eyes total motion (10.53%). In two eyes keratopathy developed (5.26%). Central vision 6/6-6/12 was achieved in 18.42%, 6/15-6/36 in 21.05%, 6/60-3/60 in 28.95% and less than 3/60 in 31.58%. In the poorer anatomical and functional results after operation of pseudophakic motions participate in addition to the above mentioned ones difficult visualization of the retinal periphery and the extent of surgical trauma during surgery of detached retinas.     

Retinal detachment in aphakia

In a prospective study five hundred consecutive cases of cataract operations were followed during ten years. Nine cases of retinal detachment were observed. In a retrospective study 77 cases with aphakic retinal detachment were studied according to type of cataract operation, interval between this operation and the onset of retinal detachment, refraction, area of detachment and results of treatment. About fifty percent of the cases of retinal detachment are observed during the first year after the cataract operation. At the first examination the detached area is usually larger in aphakic eyes than in phakic eyes. The anatomical and functional cure after detachment operation is probably less in aphakic than phakic eyes.     

Retinal detachment and sarcoidosis

A 27 year old patient with histologically proven conjunctival sarcoidosis developed a posterior uveitis with retinal giant tear and inversion of retina. The patient was treated systemically with steroids and the retinal detachment healed by usual operation, visual acuity 6/10.     

Retinal detachment and pseudophakia

Retinal detachments occur in up to 3.6% of pseudophakic patients. The intraocular lens makes it hard to see the peripheral fundus but the small pupil ophthalmoscope is a valuable help. The functional and anatomic success rates after operation are about 5% less than those of patients with aphakic retinal detachments matched for age and sex. I present fifteen cases of pseudophakic detachment. Any manipulation likely to induce contact between lens and cornea such as collapse of the globe after drainage of fluid or gas injections should be avoided. Careful examination of the fundus before and after cataract extraction and careful selection of paients for lens implantation are the only means of reducing the incidence of retinal detachment.     

Retinal detachment and pseudophakia

A consecutive series of pseudophakic retinal detachments was statistically compared with a matched group of aphakic retinal detachments. Distribution of breaks, anatomic results, and final visual acuities were tabulated. Success in reattachment was equal in the two groups, but final visual acuities were better in the aphakic group. Emphasis was placed on the intraoperative ophthalmoscopic examination of pseudophakic eyes with compromised peripheral fundus visibility.     

Retinal detachment in pseudophakia

Retinal detachment in an aphakic eye is a grave therapeutical problem. There exists some fears that cataract extraction with implantation of an artificial lens may increase the number of these complications. Three hundred and seventy cases of cataract extraction with implantation of an artificial lens performed in our department were analysed from the point of view of the incidence of retinal detachment. The cataract was extracted extra- and intracapsularly and the artificial lens was implanted in the anterior as well as in the posterior chamber. During the period of observation--4 months to 3 years--it was established that the number of the retinal detachment in pseudophakia was not larger than in aphakic eyes without implant.     

Retinal detachment and pseudophakos

With the increasing number of intraocular lensimplants the retina surgeon is more often confronted with retinal detachment after lensimplantation. The treatment of pseudophakic retinal detachment is mostly a problem of examination. The Panfunduskop of Schlegel is a very valuable aid and permits detection of most breaks situated anterior or on the equator. The article presents the results of 37 operated eyes.     

Retinal detachment in the mentally retarded

PURPOSE: To report the clinical features and surgical outcomes of retinal detachment in mentally retarded patients. METHODS: Retrospective review of records of mentally retarded patients who had retinal reattachment surgery at the authors' institutions between February 1994 and February 2000. There were 8 patients with 13 surgically treated eyes. Demographic and clinical data were abstracted from the patients' medical records. RESULTS: The retina of 12/13 (92%) eyes remained reattached after a follow-up ranging from 9 to 78 months. In 6 eyes of the 4 patients whose visual acuity (VA) could be determined, VA improved in 5 eyes of 3 patients. In the remaining 4 patients whose VA could not be determined, improved behavioral patterns suggesting a successful surgical outcome were observed in 3 patients with bilateral retinal detachment, although in one of these patients only unilateral retinal reattachment was achieved. The findings in the eyes in this study agree with the findings in reports on patients with traumatic retinal detachment. CONCLUSIONS: The retinal reattachment rate is fair in the mentally retarded compared with the rate in other segments of the population. Ophthalmological examinations should be provided regularly for mentally retarded persons to keep open the possibility for early sight-improving surgery.