Intraocular Lens Power Calculation after Refractive Surgery: A Comparative Analysis of Accuracy and Predictability

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation using conventional regression formulae or the American Society of Cataract and Refractive Surgery (ASCRS) IOL power calculator for previous corneal refractive surgery. METHODS: We retrospectively reviewed 96 eyes from 68 patients that had undergone cataract surgery after keratorefractive surgeries. We calculated the formula with two approaches: IOL powers using the ASCRS IOL power calculator and IOL powers using conventional formulae with previous refractive data (Camellin, Jarade, Savini, and clinical history method) or without prior data (0, 2 and, 4 mm total mean power in topography, Wang-Koch-Maloney, Shammas, Seitz, and Maloney). Two conventional IOL formulae (the SRK/T and the Hoffer Q) were calculated with the single K and double K methods. Mean arithmetic refractive error and mean absolute error were calculated at the first postoperative month. RESULTS: In conventional formulae, the Jarade method or the Seitz method, applied in the Hoffer Q formula with the single K or double K method, have the lowest prediction errors. The least prediction error was found in the Shammas-PL method in the ASCRS group. There was no statistically significant difference between the 10 lowest mean absolute error conventional methods, the Shammas-PL method and the Barrett True-K method calculated with using the ASCRS calculator, without using preoperative data. CONCLUSIONS: The Shammas-PL formula and the Barrett True-K formula, calculated with the ASCRS calculator, without using history, were methods comparable to the 10 most accurate conventional formulae. Other methods using the ASCRS calculator show a myopic tendency.

A Case of Tubulointerstitial Nephritis and Uveitis Syndrome in an Elderly Patient

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease entity usually occurring in children. In the present study a case of TINU syndrome in an elderly patient is described and relevant literature is reviewed. A 61-year-old man presented with bilateral flank pain, urinary frequency, and foamy urine. A kidney ultrasonography revealed an increase in kidney parenchyma echogenicity. Following a kidney biopsy, the patient was diagnosed with acute tubulointerstitial nephritis. An ophthalmology examination initially performed for floater symptoms, revealed anterior uveitis in both eyes. Acute tubulointerstitial nephritis and anterior uveitis in both eyes responded to treatment with oral prednisolone, furosemide, carvedilol, and a topical steroid. TINU syndrome can occur in the elderly and should be part of the differential diagnosis when seeing a patient who has uveitis in association with renal disease; any therapy should be managed by both an internist and an ophthalmologist.

Comparative Analysis of Corneal Refraction and Astigmatism Measured with Autokeratometer, IOL Master, and Topography

PURPOSE: To comparatively analyze the repeatability and consistency between different methods of measuring corneal refraction and astigmatism in order to precisely determine the toric intraocular lens target. METHODS: The medical records of 254 eyes of 192 persons were retrospectively reviewed to compare the repeatability of corneal refraction measured with autokeratometer, IOL Master, and topography. The axis and the amount of the astigmatism were compared between these methods. The differences between the estimated spherical equivalents using measured corneal refractive values and the actual spherical equivalents after cataract surgery were compared to evaluate the expected astigmatic error of each measurement. RESULTS: The average corneal refraction was greater with topography than with IOL Master or autokeratometer. Astigmatism calculated with IOL Master was greater than that measured with topography or autokeratometer. The mean coefficient of variation for mean corneal refraction was 0.19% with autokeratometer, which was smaller than that with IOL Master or topography. In patients with more than 1.5D of astigmatism, there were no significant differences in the axis measured by each instrument. The expected spherical error in IOL calculation was smaller with the measured values from IOL Master and autokeratometer than were those with topography. CONCLUSIONS: The repeatability of measurements for corneal refraction and astigmatism was significantly higher using the autokeratometer and IOL Master, with the highest astigmatic value observed with the IOL master. The axis of astigmatism for each method was consistent in the patients with more than 1.5D of astigmatism.

Presumed Necrotizing Viral Retinitis after Intravitreal Triamcinolone Injection: Case Report

A 56-year-old man presented with anterior chamber inflammation, increased intraocular pressure, peripheral retinal infiltration, and generalized retinal arterial obstruction suggesting acute retinal necrosis five months after intravitreal triamcinolone acetonide injection (IVTA). He was treated with intravenous antiviral agents and aspirin. Shortly after treatment, retinal infiltrations were resolved, and partial recanalization of the obstructed vessel was observed. Viral retinitis may occur as an opportunistic infection following IVTA due to the local immune modulatory effect of the steroid; hence, close observation following IVTA is necessary.

A Case of Alkali Burn Treated With Amniotic Membrane Graft and Forniceal Reconstruction

PURPOSE: To report a case of alkali burn treated successfully with early surgical intervention including amniotic membrane graft and forniceal reconstructionand the restored visual acuity. CASE SUMMARY: A 23-year-old woman was referred for alkali burn of her right eye after being splashed with a drop of 40% sodium hydroxide. Slit-lamp microscopic examination showed the patient's cornea was edematous, and hazy and limbal ischemia involved half of the cornea, which can supposedly lead to eyelid deformity and symblepharon. Debridement of all necrotic tissues, immediate amniotic membrane permanent graft and transient forniceal covering with amniotic membrane were conducted a day after the burn. Corneal and conjunctival epithelial defects were completely healed in five weeks, and visual acuity was restored to 20/20 in eight weeks. Additional surgeries for allogenic limbal transplantation and autologous oral mucosal graft were performed to resolve symblepharon.