Effect Of Prolonged Monocular Occlusion On Latent Nystagms

The authors recorded nystagmus during seeing with one eye in eight patients with latent nystagmus (LN) before and after two or three days of prolonged occlusion of the better eye (POBE). Before POBE, the slow-phase speed of the nystagmus (SPS) was usually higher when the better eye was covered. After POBE, the SPS during cover of the better eye had decreased and the SPS during cover of the poorer eye had increased (please note the time difference between ‘prolonged occlusion’ and ‘cover'). However, the sum of the two speeds (absolute values, for they were opposite in direction) remained the same in all cases. This indicates that the principal component of the LN, the difference between LN with right-and LN with left-eye cover, remained the same, but a drift towards the poorer eye had been added that decreased the SPS during cover of the better eye and increased the SPS during cover of the poorer eye. In three patients who had oscillopsia during POBE, the oscillopsia gradually decreased over days during POBE, indicating that the drift changes slowly, over a period of days. As regards occlusion therapy in children with amblyopia and latent nystagmus, based on these findings, it seems advisable to occlude the better eye during days per week, rather than during hours per day: Then there is more time for the nystagmus to decrease, so that amblyopia therapy can be more effective

In Graves' disease, increased muscle tension and reduced elasticity of affected muscles is primarily caused by active muscle contraction

In three patients with Graves' disease of recent onset, length-tension diagrams were made during surgery for squint under eyedrop anesthesia, while the other eye looked ahead, into the field of action, or out of the field of action of the muscle that was measured. The affected muscles were found to be very stiff when the other eye looked straight ahead. Unexpectedly, the affected muscle did not shorten any further (one case) or only 6-7 mm (two cases) when the other eye looked into the field of action of the muscle, whereas it lengthened 9-10 mm when the other eye looked out of the field of action of the muscle. This means that the raised muscle tension and reduced elasticity of affected muscles in these cases of Graves' disease of recent onset are caused by active muscle contraction. It has been found previously that hyperthyroidism, induced in rats, casues transitions from slower to faster myosin-heavy chain (MHC) types. The findings seem compatible with a transition of slow into fast muscle fiber types in Graves' disease

Endophthalmitis after strabismus surgery: incidence and outcome in relation to age, operated eye muscle, surgical technique, scleral perforation and immune state

Purpose: Identify risk factors for endophthalmitis after strabismus surgery (EASS) and relate these to incidence and outcome. Methods: Ophthalmologists, who had operated, diagnosed or treated EASS, completed a case record form with 71 questions in six domains: Preoperative, Surgery, Perforation, Postoperative, Outcome and Experts’ opinion. To estimate the age-specific incidence per number of strabismus operations in the Netherlands during 1994-2013, the age distribution of Dutch cases was compared with the age-specific rates of strabismus surgery in the Dutch Registry of Strabismus Operations and with population data. Exploratory data analysis was performed. The immune state was evaluated in six patients. Five enucleated eyes were studied histopathologically. Results: None of the 26 patients (27 eyes with EASS) were between 9 and 65 years old, except for one patient with retinal haemorrhage followed by endophthalmitis. In the Netherlands during 1994-2013, the rate of EASS was approximately one per 11 000 strabismus operations, but one per 4300 for children aged 0–3 and one per 1000 for patients 65 and older. Endophthalmitis was diagnosed on postoperative day 1–4 in children aged 0–3. In all 15 children aged 0–5, the 16 affected eyes were phthisical, eviscerated or enucleated. The involved eye muscle had been recessed in 25 of 27 cases. It was a medial rectus in 15 of 16 children aged 0–6. It was a lateral (6), inferior (2) or medial (1) rectus in elderly. Scleral perforation went unnoticed in all children (no record in three) and in two of seven elderly (no record in two). Histopathology showed transscleral scarring compatible with scleral perforation in four patients but, in a two-year-old girl who had EASS together with a transient medial rectus palsy, the sclera underneath the former suture tract was not perforated but did contain the long posterior ciliary artery. Conclusions: Endophthalmitis after strabismus surgery (EASS) affects children and elderly, with a grave outcome in young children. It occurs after recession of the medial rectus muscle in children, and it may occur without scleral perforation. Age and perforation influence many other parameters that determine the occurrence and fulminance of EASS