Retinal abnormalities

Patients who have had cataract extraction with implantation of an intraocular lens (lOL) often have pupils that dilate less well than they did preoperatively.The poorer pupillary response probably relates to the amount of iris trauma occurring at surgery. The difference in mydriatic response may affect evaluating and treating peripheral retinal abnormalities in aphakic and pseudophakic eyes. However, even with maximally dilated pupils often the capsulotomy is the limiting fector. 

Side effects of these drugs include CNS effects (e.g., headache, nervousness, insomnia, and others), rashes, dermatitis, pigmentary changes of the skin and hair, gastrointestinal disturbance (e.g., nausea), and reversible ocular toxicities such as cycloplegia and corneal deposits. Potentially serions retinal toxicity is uncommon when the currently recommended doses are used and is least common with hydroxychloroquine. However, because of the possibility of permanent damage associated with the retinopathy, an ophthalmologic evaluation should be done at baseline and every 3 months when chloroquine is used and every 6 to 12 months when hydroxychloroquine is used. If retinal abnormalities are noted, antimalarial therapy should be discontinued or the dose reduced. ... 

CNV secondary to pathologic myopia (distance correction of at least -6.0 D, spherical equivalent, or less myopic than -6.0 D with retinal abnormalities consistent with pathologic myopia, such as lacquer cracks, and an axial length at least 26.5 mm CNV under the geometric center of the foveal avascular zone Area of CNV at least 50% of the area of the total neovascular lesion Greatest linear dimension of lesion <5400 pm (not including any area of prior laser photocoagulation)... 

In several instances severe bone marrow depression occurred, characterized by neutropenia and thrombocytopenia. The clinical chemistry profile of these cases revealed hypocholesterolemia, hyperuricemia, and hypoproteinemia. In a few cases, slight disturbance of liver function was found with mild elevations of aminotransferases. In male subjects, azoospermia or abnormal spermatozoa and reduced motility of spermatozoa were observed. Some cases presented with postexposure lacrimation, hyperemia, and edema of the conjunctiva. There were instances of protracted reduction in visual capacity and reports of retinal abnormalities [45]. Lymphocytes from exposed subjects showed a considerable number of chromosomal aberrations [46,47]. 

Retinal abnormalities like those which are consistently observed in Tay-Sachs disease, and which occur frequently in Niemann-Pick disease, are not a feature of GD. Here, pinguecula-like formations are frequent which consist of yellowish proliferations of the bulbar conjunctiva near the sclero-corneal junction, usually on the nasal side. These changes which may be seen normally in elderly people, occur more frequently in Gaucher patients, where they have a dark-yellow to brownish color which deepens with increasing age. In this form they have been considered pathognomonic for GD by some authors (Pick 1926, Schettler 1955) and were described as early as 1901 in two siblings by Brill. A bilateral occurrence is found in about of patients with the disease (Fredrickson and Hofmann 1960/66). 

Interphotoreceptor retinoid binding protein (IRBP) occupies the space between the RPE and the rod outer segment (ROS), the interphotoreceptor matrix, and binds both llcROH and llcRCHO. Retinoids do not require IRBP for transfer between the two membranes, however, because IRBP null mice show no gross abnormalities of the visual cycle, even though they have severe retinal abnormalities. Although retinoids have very limited solubility in the aqueous phase, membranes of the RPE and ROS transfer retinoids between them in the absence of IRBP. 

Cardioembolism Cardioembolism accounts for approximately 30% of all stroke and 25-30% of strokes in the young (age <45 years)." AF accounts for a large proportion of these strokes (15-25%). Symptoms may be suggestive, but they are not diagnostic. Repetitive, stereotyped, transient ischemic attacks (TIAs) are unusual in embolic stroke. The classic presentation for cardioembolism is the sudden onset of maximal symptoms. The size of the embolic material determines, in part, the course of the embolic material. Small emboli can cause retinal ischemic or lacunar symptoms. Posterior cerebral artery territory infarcts, in particular, are often due to cardiac embolism. This predilection is not completely consistent across the various cardiac structural abnormalities that predispose to stroke, and may be due to patterns of blood flow associated with specific cardiac pathologies. 

Patients with abetalipoproteinaemia, a rare inborn disorder of lipoprotein metabolism, are totally deficient in vitamin E fiom birth and, if untreated, invariably develop a characteristic pigmentary retinopathy similar to that seen in retinitis pigmentosa and peroxisomal disorders. The same retinopathy has been observed in other patients with severe and chronic vitamin E deficiency. A essive vitamin E replacement therapy in all these patients has been shown either to prevent, to halt the progression of, or in some cases, to improve the characteristic visual abnormalities (Muller and Lloyd, 1982). 

Hydroxychloroquine may cause retinal toxicity, and patients must have their eyes examined at least annually to detect this abnormality. It is not associated with renal, hepatic, or bone marrow suppression and therefore may be an acceptable treatment option for patients with contraindications to other DMARDs because of their toxicities. 

Kowluru, R. A., B. Menon et al. (2008). Beneficial effect of zeaxanthin on retinal metabolic abnormalities in diabetic rats. Invest. Ophthalmol. Vis. Sci. 49(4) 1645-1651. 

Taurine deficiency is rare in adult humans but is common in domestic cats, due to poor absorption from tinned catfood. Consequences of taurine deficiency in cats are cardiomyopathy, retinal degradation, reproductive failure in females, developmental abnormalities and impairment of the immune system. It is possible that a chronic deficiency in humans may have similar effects. 

Visual abnormalities Retinal vascular thrombosis has been reported. Discontinue medication pending examination if there is sudden partial or complete loss of vision or a sudden onset of proptosis, diplopia, or migraine. 

Foscarnet (Foscavir) [Antiviral] Uses CMV retinitis acyclovir-resistant hCTpes Infxns Action -1- Viral DNA polym ase RT Dose CMV retinitis Induction 60 mg/kg IV qSh or 100 mg/kg ql2h X 14—21 d Meant 90-120 mg/kg/dIV (Moo.-Fiti ) Acyclovir-resistant HSV Induction 40 mg/kg IV q8-12h x 14—21 d use central line -1- w/ renal impair Caution [C, —] T Sz potential w/ fluoroquinolones avoid n hrotoxic Rx (cyclosporine, aminoglycosides, ampho B, protease inhibitors) Contra CrCl <0.4 mL/min/kg Disp Inj SE Nephrotox, electrolyte abnormalities Interactions T Risks of Sz W/ quinolones t risks of n hrotox W/ aminoglycosides, amphotCTicin B, didanosine, pentamidine, vancomycin EMS Known to cause electrolyte disturbances (extremity numbness paresthesia indicates electrol5rte unbalance) monitor ECG OD May cause extremity numbing, and Szs hydrate w/ IV fluids... 

Possible abnormalities that can be observed include microphthalmia/anophthalmia, retinal fold, dilated lateral ventricles, and hemorrhages affecting the brain. 

French J (2008) Retinal folding in the term rabbit fetus developmental abnormality or fixation artifact. Reprod Toxicol 26 262-266... 

Li 1, Patil RV, Verkman AS (2002) Mildly abnormal retinal function in transgenic mice without Muller cell aquaporin-4 water channels. Invest Ophthalmol Vis Sci 43 573—579 Ma T, Yang B, Gillespie A, Carlson El, Epstein Cl, Verkman AS (1997) Generation and phenotype of a transgenic knockout mouse lacking the mercurial-insensitive water channel aquaporin-4. 1 Clin Invest 100 957-962... 

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